e-ijpm: vol. 45/4 - cloud object storage | store ...s3.amazonaws.com/zanran_storage/ · 11 2009...

��

��

��

��

��

�� !�"��#��$��

"��%&�� '��%( ��&��$��)��'��

*� ��%)��'��!

+��,��

45/4

powdermetallurgy

international journal of

2009 PM Design Excellence AwardsThe PM Industry in North America—2009Laser-Engineered Net Shaping of Fe-Based Metallic GlassesExothermic Reactions During Sintering of Iron and

Aluminum

INTERNATIONAL

international journal of

powdermetallurgy

The International Journal of Powder Metallurgy (ISSN No. 0888-7462) is a professional publication serving the scientific and tech-nological needs and interests of the powder metallurgist and the metal powder producing and consuming industries. Advertisingcarried in the Journal is selected so as to meet these needs and interests. Unrelated advertising cannot be accepted.

Published bimonthly by APMI International, 105 College Road East, Princeton, N.J. 08540-6692 USA. Telephone (609) 452-7700. Periodical postage paid at Princeton, New Jersey, and at additional mailing offices. Copyright © 2009 by APMI International.Subscription rates to non-members; USA, Canada and Mexico: $100.00 individuals, $230.00 institutions; overseas: additional$40.00 postage; single issues $55.00. Printed in USA by Cadmus Communications Corporation, P.O. Box 27367, Richmond,Virginia 23261-7367. Postmaster send address changes to the International Journal of Powder Metallurgy, 105 College Road East,Princeton, New Jersey 08540 USA USPS#267-120

ADVERTISING INFORMATIONJessica Tamasi, APMI International105 College Road East, Princeton, New Jersey 08540-6692 USATel: (609) 452-7700 • Fax: (609) 987-8523 • E-mail: [email protected]

INTERNATIONAL

EDITORIAL REVIEW COMMITTEE P.W. Taubenblat, FAPMI, ChairmanI.E. Anderson, FAPMIT. AndoS.G. CaldwellS.C. DeeviD. DombrowskiJ.J. DunkleyZ. FangB.L. FergusonW. FrazierK. Kulkarni, FAPMIK.S. KumarT.F. Murphy, FAPMIJ.W. NewkirkP.D. NurthenJ.H. PerepezkoP.K. SamalD.W. Smith, FAPMIR. TandonT.A. TomlinD.T. Whychell, Sr., FAPMIM. Wright, PMTA. Zavaliangos

INTERNATIONAL LIAISON COMMITTEED. Whittaker (UK) ChairmanV. Arnhold (Germany)E.C. Barba (Mexico)P. Beiss, FAPMI (Germany) C. Blais (Canada)P. Blanchard (France)G.F. Bocchini (Italy)F. Chagnon (Canada) C-L Chu (Taiwan)O. Coube (Europe)H. Danninger (Austria)U. Engström (Sweden)O. Grinder (Sweden)S. Guo (China)F-L Han (China)K.S. Hwang (Taiwan)Y.D. Kim (Korea)G. L’Espérance, FAPMI (Canada)H. Miura (Japan)C.B. Molins (Spain)R.L. Orban (Romania)T.L. Pecanha (Brazil)F. Petzoldt (Germany)G.B. Schaffer (Australia)L. Sigl (Austria)Y. Takeda (Japan)G.S. Upadhyaya (India)

Publisher C. James Trombino, CAE [email protected]

Editor-in-Chief Alan Lawley, [email protected]

Managing EditorJames P. [email protected]

Contributing EditorPeter K. [email protected]

Advertising ManagerJessica S. [email protected]

Copy EditorDonni [email protected]

Production AssistantDora [email protected]

President of APMI International Nicholas T. [email protected]

Executive Director/CEO, APMI International C. James Trombino, CAE [email protected]

2 Editor's Note4 PM Industry News in Review7 PMT Spotlight On …Shawn Metcalfe9 Consultants’ Corner O. Grinder

11 2009 APMI Fellow Award12 2009 Poster Awards15 2009 PM Design Excellence Award Competition Winners20 Axel Madsen/CPMT Scholar Reports

ENGINEERING & TECHNOLOGY 23 State of the PM Industry in North America—2009

M. Paullin

RESEARCH & DEVELOPMENT 27 Processing and Behavior of Fe-Based Metallic Glass

Components via Laser-Engineered Net ShapingB. Zheng, Y. Zhou, J.E. Smugeresky and E.J. Lavernia

40 Exothermic Reactions During the Sintering of ElementalIron and Aluminum Powder MixesS. Józwiak, K. Karczewski and Z. Bojar

DEPARTMENTS45 Meetings and Conferences46 Instructions for Authors48 Advertisers’ Index

Cover: Grand Prize–winning parts from MPIF’s 2009 Design Excellence Awards Competition

Contents 45/4 July/August 2009

EDITOR’S NOTE

Volume 45, Issue 4, 2009International Journal of Powder Metallurgy 2

Notwithstanding the major global economic downturn, and its direct andindirect impacts on the PM industry, PowderMet2009 will go on recordas an unqualified success by the 600-plus delegates who experienced a

high-quality technical program embracing the PM and particulate materialsspectrum. The special interest program on developments in titanium PM drewa “standing room only” audience with the expectation that this technology ispoised for further commercialization and market penetration.

In this post-show issue of the Journal, the text of the “State of the PMIndustry in North America—2009,” presented by MPIF President Mark Paullin,is included. Also, Peter Johnson reviews the “2009 PM Design ExcellenceAwards Competition.” The Grand Prize–winning parts are shown on the frontcover.

As a further postscript to PowderMet2009, the four Axel Madsen/CPMTScholar reports again confirm the value of this program in encouraging students to learn more about PM technology and to consider a professionalcareer in the PM industry. In different ways, each of the grantees derived tangible and indirect benefits by attending the conference and exhibition.

International consultant Olle Grinder is the author of the “Consultants’Corner.” Readers’ questions he addresses focus on the projected growth of hotisostatic pressing (HIP), the mechanical properties of HIPed metals comparedwith their cast/wrought counterparts, and materials selection for PM tooling inthe compaction of soft magnetic materials.

In the “Research & Development” section, Jozwiak et al., examine theexothermic self-propagating high-temperature synthesis (SHS) reaction thatoccurs during the sintering of elemental mixes of iron and aluminum powder.The study confirms that the SHS reaction temperature and enthalpy are afunction of the aluminum content, and that formation of the intermetallics(FeAl3, Fe2Al5, and FeAl) is complex.

Recently, I read a paper published in Metallurgical and MaterialsTransactions on the processing, microstructure, and properties of iron-basedmetallic glasses utilizing laser-engineered net shaping. To the author’s knowledge, the study represents the first time that the fabrication of net-shaped bulk metallic glass components has been demonstrated by laser directdeposition. In light of its potential interest to readers of the Journal, the articleis reproduced in the “Research & Development” section.

I am usually cautious when opening e-mail communications from unknownsources. However, the title of a recent, somewhat macabre, entity “On theHighway to Heaven,” piqued my curiosity. Invented by Steve Radz, the idea ofa Mobile Cremation Urn came to him as an epiphany in a dream! An aspiringfuneral director, Radz developed the concept into a unique patented productwhich his company manufactures: galvanized, chrome- or nickel-plated, andpowder-coated urns in a variety of colors—clearly an opportunity here for themetal powder producers! These Final Ride Urns are made to last several lifetimes, braving the elements and the open road, keeping the memory of aloved one alive, close, and cruising. Though developed for the motorcycle, theurns can be mounted on any vehicle, for example, a golf cart. The rider can, ofcourse, also stay close to past four-footed friends with these urns. Happy riding. For more information visit: www.1FinalRide.com.

Alan LawleyEditor-in-Chief

2010 International Conference on Powder Metallurgy & Particulate Materials

June 27–30The Westin DiplomatHollywood (Ft. Lauderdale), Florida

For complete program and registration information contact:METAL POWDER INDUSTRIES FEDERATION ~ APMI INTERNATIONAL105 College Road East, Princeton, New Jersey 08540 USATel: 609-452-7700 ~ Fax: 609-987-8523 ~ www.mpif.org

INTERNATIONAL

Pow

derM

et2010

Pow

derM

et2

010


ijpm

PM INDUSTRY NEWS IN REVIEW

Höganäs Powder Sales Sag Swedish metal powder producerHöganäs AB reports first quarter2009 sales declined 42 percent toMSEK 916 (about $112 million).Production volumes fell sharply inall regions.

Chinese PM Industry Results PM parts production in Chinadeclined five percent to 102,048short tons last year, reports the PMAssociation of China, Beijing. Iron-base parts production declined to95,706 short tons while copperparts production weakened slightlyto 6,342 short tons.

New Resource for MetalInjection Molding Information The Metal Injection MoldingAssociation (MIMA), one of the sixfederated trade associations of theMetal Powder IndustriesFederation (MPIF), has launched anew industry-funded Web site,mimaweb.org, to promote the ben-efits of metal injection molding(MIM) as a part-manufacturingtechnology.

Miba Advances amid SofteningSales Miba AG, Laakirchen, Austria,announced a 2.1 percent increaseof fiscal year 2008–09 sales to 374.6 million (about $508 mil-lion), despite a sharply decliningfourth quarter. Based on the slow-down in the automotive market, theSinter (PM parts) Group reported a

15 percent sales drop to 135.4million (about $183 million).

New Powder Production LineIncreases CapacityTekna Plasma Systems Inc.,Sherbrooke, Québec, Canada, hasinstalled a new induction plasmaproduction line for metal andceramic powders. Chiefly devotedto spherical cast tungsten carbide(SWC) powder and customizedpowder treatments, the new lineincreases Tekna’s annual capacityto more than 250 metric tons.

GKN Sales Decline Automotive giant GKN plc,London, U.K., reports an eightpercent drop in first quarter salesto £1,085 million (about $1.6 bil-lion). However, excluding theacquisition of Filton from Airbus,group sales fell by 33 percent.

Kennametal Sells High-SpeedSteel Line to Chinese CompanyKennametal Inc., Latrobe, Pa., hasagreed to sell its high-speed drills,related product lines, and assetsto Top Eastern Drill Co., Ltd.(TDC), a member of the Top-Eastern Group, Dalian, China.The transaction includes fourfacilities in the U.S., Mexico, andChina, as well as 400 employees.

Metaldyne Joins BankruptcyParade Metaldyne, Plymouth, Mich., joinsa long line of automotive parts

suppliers filing for Chapter 11bankruptcy, a direct result of fal-tering North American vehiclesales and production. The filingdoes not include the company’snon-U.S. operations or Asahi TecCorp., its parent company.

H.C. Starck Signs RefractoryMetal Supply Agreement H.C. Starck Inc., Newton, Mass.,and Comet Network Co., Ltd.,Seoul, South Korea, have reacheda long-term agreement for thesupply of refractory metal forsputtering targets. Starck willsupply molybdenum materialsfrom its plant in Euclid, Ohio, andwill make additional capacityinvestment there as necessary tomeet Comet’s requirements.

New PM Development Facility TAT Technologies, Inc., Summit,N.J., will open a TechnologyDevelopment & Training Center ina recently acquired 5,000 sq. ft.building located in the Stackpolecomplex in St. Marys, Pa., reportsHarb S. Nayar, president. Thefacility will be used for technologydevelopment, new equipmentdemonstration, pilot-run process-ing, and hands-on training in sin-tering, delubing/debinding,annealing, and brazing and otherthermal processes.

High-Alumina Bricks for PMFurnacesSunrock Ceramics Cmpany, LLC,

The following items have appeared in PM Newsbytes since the previousissue of the Journal. To read a fuller treatment of any of these items, goto www.apmiinternational.org, login to the “Members Only” section, andclick on “Expanded Stories from PM Newsbytes.”



Chicago, Ill., offers 99.5 percentalumina bricks and othershapes for PM furnace applica-tions, which have been fieldtested recently in the U.S. andEurope. The high-density mate-rial, designated HPA-99, is idealfor hot-face linings in high-tem-perature hydrogen-atmospheresintering furnaces, the companyreports.

SCM Buys Brazing Business SCM Metal Products, Inc.,Research Triangle Park, N.C.,has purchased the brazing prod-uct line from Tricon Industries,Downer’s Grove, Ill. The assetpurchase included all of Tricon’sequipment, customer list, formu-lations of copper, copper alloyand nickel-based brazing pastes,and intellectual property.

Metallurgy & ParticulateMaterials. Mark C. Paullin, MPIFpresident, and C. JamesTrombino, MPIF executive direc-tor/CEO, welcomed the dele-gates at the opening general ses-sion on June 29.

Industry Recognition Awards C. James Trombino, MPIF exec-utive director/CEO, announcedthe MPIF Board of Governors’decision to rename the annualOutstanding Technical PaperAward in honor of the lateHoward Sanderow, well-knownconsultant and powder metallur-gist. “The Howard I. SanderowOutstanding Technical PaperAward recognizes excellence inscientific and technical writtencommunication and now carries,in perpetuity, the legacy of a

Automotive PM Parts MakerReports Sales and EarningsSlump Miba AG, Laakirchen, Austria,reports a 27 percent decline inits fiscal first quarter sales to74.3 million euros (about $103million). Earnings plunged to1.2 million euros (about $1.7million) compared to 13.3 mil-lion euros (about $18.5 million)during the same period in 2008.

Industry Leaders Meet in Las Vegas Executives, technical managersand researchers from metalpowder producers, PM parts andproducts makers, equipmentbuilders, and universities aregathered in Las Vegas for thePowderMet2009 InternationalConference on Powder

PURCHASER & PROCESSOR

Powder Metal Scrap

Green, Sintered, Floor Sweeps, Furnace & Maintenance Scrap

1403 Fourth St. • Kalamazoo, MI 49048 • Tel: 269-342-0183 • Fax: 269-342-0185Robert Lando

E-mail: [email protected]

Ferrous & Non-Ferrous Metals

(800) 313-9672Since 1946



truly great technical contributor to our conferences,”Trombino said. The award was presented to ChrisSchade and Thomas F. Murphy, Hoeganaes Corpora-tion, and Alan Lawley and Roger Doherty, DrexelUniversity, for their paper presented at the 2008 PMWorld Congress, “Development of a Dual-PhasePrecipitation-Hardening PM Stainless Steel.”

The MPIF Distinguished Service to Powder MetallurgyAward, which recognizes contributions of individualswho have done excellent work in the PM industry for atleast 25 years, was presented to the following industryprofessionals: Gary L. Anderson, John C. Hebeisen,Thomas J. Jesberger, Shiz Kassam, Lou Koehler,Kalathur S. Narasimhan, FAPMI, Charles L. Rose, JohnA. Shields, Jr., Thomas L. Stockwell, Jr., Ted A. Tomlin,and Robert F. Unkel.

PM Industry Trends In the annual State of the PM Industry presentation atPowderMet 2009 in Las Vegas, MPIF President Mark C.Paullin reports that North American iron powder ship-ments declined 19 percent in 2008 to 327,272 shorttons. Total metal powder shipments declined 18.4 percent to 415,427 short tons.

Outstanding PM Parts Applications Winners of the 2009 Powder Metallurgy DesignExcellence Awards Competition sponsored by the MetalPowder Industries Federation were announced atPowderMet2009. Receiving grand prizes and awards ofdistinction, the winning parts are outstanding examplesof powder metallurgy’s (PM) precision, performance,complexity, economy, and innovation.

Ametek Acquires Hoeganaes Stainless Steel PowderBusiness AMETEK Specialty Metal Powders (SMP), Eighty Four,Pa., has purchased the ANCOR® Specialties stainlesssteel powder business from Hoeganaes Corporation,Cinnaminson, N.J. The acquisition includes the cus-tomer list and an annealing furnace that will be movedto the Eighty Four plant.

New PM Machining Operation Opens Super Abrasive Machining Innovations LLC (SAMπ)offers machining services for as-sintered and as-heat-treated materials at its new 7,500 sq. ft. facility inRidgway, Pa., reports Rocco Petrilli, CEO of PrimaBusiness Specialists LLC and SAMπ. The company provides high-volume precision grinding at speeds andcosts similar to those generated by single-point machin-ing that will enhance net shaping. ijpm


Education:Chemical Engineering Technology Diploma, Mohawk

College, 2001

Why did you study powder metallurgy/particulatematerials?My job often involves the examination of the influenceof a specific material on an entire process. Thus, it wasnecessary to be aware of the wide variety of pertinenttechnologies and manufacturing steps. At the begin-ning, I found both the Basic PM Short Course and thePMT certification program to provide an excellent foun-dation.

When did your interest in engineering/science begin?I have always been interested in sci-ence. Even at a young age I was inter-ested in general science and the solarsystem. I did not realize that this wasto be my chosen career path until mylast years in high school. Under a gov-ernment co-op program I worked in acoal-fired hydro generating station.Working in an industrial laboratorywith hands-on experience in chemistrypersuaded me to continue my education in a relatedfield.

What was your first job in PM? What did you do? I assembled a small apparatus, which involved spread-ing powder mixes over a fine- mesh screen and thenexposing the powder to a gas stream. This was followedby analyzing the composition and the weight loss todetermine their impact on powder mixes during bothhandling and transportation.

Describe your career path, companies worked for,and responsibilities.Most of my work experience has been with Vale IncoLimited. I started as a technician for the Hydro-metallurgy Research Group on a one-year co-op term.The work focused on the extraction of nickel, cobalt,and precious metals from the ore. I found this chal-

lenging and interesting, as the entire industrial processwas reproduced on a laboratory scale. After completingcollege, I accepted a position at Vale Inco in electro-magnetic shielding research. This work focused ontechnologies for plating nickel onto carbon substratesand then incorporating the product into plastic injec-tion molding. I then transferred to the BatteryResearch Group which gave me my first experiencewith metal powders. My interest in this field grew and Itransferred to the PM group, and have been with thisgroup for four years. My work focuses on customersupport, product application development, and techni-cal support for our operations.

What gives you the most satisfactionin your career?I get the most satisfaction from theconstant learning experience providedby working on materials preparation,and the testing of PM steels, hardmet-als, diamond tool binders, and heavyalloys, involving practically every stepin PM manufacturing.

List your MPIF/APMI activities.Vale Inco Limited supports participa-

tion in short courses, and attendance and presentationof technical papers at MPIF conferences, as well as thePMT certification program.

What major changes/trend(s) in the PM industryhave you seen?The sharp rise in raw-materials prices a few years agoput pressure on the selection of alloying elements in

SPOTLIGHT ON ...

SHAWN METCALFE, PMT

Research Technologist Product Application and Technology DepartmentVale Inco Limited2060 Flavelle Blvd. Sheridan ParkMississauga, Ontario L5K 1Z9 Canada Phone: 905-403-4720Fax: 905-403-2401E-mail: [email protected]

SPOTLIGHT ON ...SHAWN METCALFE, PMT


high-strength steels. Now the situation hasreversed, with the world economy struggling andraw-materials costs at below historical averages.This presents high-strength PM steels with anopportunity to expand into parts that have histor-ically been uncompetitive with alternative metal-forming technologies. I see alloying content infuture PM parts being optimized to allow partsmanufacturers the ease of processing to higherdensities, which can grow PM’s advantage andmarket share.

Why did you choose to pursue PMT certification?PM is a broad field and with each project I waslimited in knowledge based on my experiencealone. PMT certification offered an avenue toexpand my knowledge across many scientificfields and to test myself. This has improved myability to communicate with customers and tomake me aware of the advantages and limitationsof the PM process, from start to finish.

How have you benefited from PMT certificationin your career?It has encouraged me to become familiar withareas of PM that are outside those of my workresponsibilities. This has helped me to bettercommunicate with customers and colleagues.

What are your current interests, hobbies, andactivities outside of work?I enjoy taking on renovation projects. These arefrequently not your normal projects, and oftenexpand into weeks of planning and work, andhave included building, with friends, an entirehouse, from the foundation up. When not reno-vating I generally spend time with my wife andclose family. ijpm

Would you like to be featured here? Have you been PMTCertified for more than 2 years? Contact Dora Schember([email protected]) for more information.

Which powder metallurgy (PM) technologywill achieve the highest growth in the next

five years? What is the projected growth ofselective net-shape hot isostatically pressed(HIPed) PM products over the next five yearsand what is driving this growth?

Before I answer this important and difficultquestion, it is appropriate to quote the

Swedish author Falstaff Fakir (pseudonym), who150 years ago stated: “It is difficult to foresee—especially about the future.”

I want to limit my forecast to the five dominantpowder-shaping and -compaction methods, i.e.,uniaxial pressing, metal injection molding (MIM),powder forging (PF), HIPing, and laser/electronbeam sintering. My firm belief is that the HIPing ofhigh-alloy PM steels will see the highest growthrate of these five methods in the next five years.The HIP production volume of billets, semi-fin-ished products, and near-net-shape (NNS) partswill continue to expand. There are several concur-rent reasons to support my selection:

• Significant improvements and important devel-opments in HIPing equipment, resulting in

° Larger HIP units with a maximum load >30mt

° Faster cycle times—now down to 12 h

° A 100% increase in the number of cycles/yr.over the last decade

° A 65% decrease in the relative cost of HIPingover the last two decades

• Extensive investments in large and modernproduction facilities, e.g., MEGA HIP units byBodycote Hot Isostatic Pressing AB, Sweden,and Kinzoku Giken, Japan, as well as in pro-duction facilities for inert-gas-atomized pow-ders by Erasteel Kloster AB, Sweden.

• The recent introduction of high-performancesteels developed specifically for the production(inert-gas atomization + HIPing) of nitrogen-

alloyed tool steelsand high-tempera-t u r e / o x i d a t i o n -resistant steels.

• New applications forn e a r - n e t - s h a p eparts and increasedknowledge on howto design the capsules and run the HIPingprocess in order to obtain NNS parts with opti-mal shape and properties.

Thus, the projected increase in production in thecoming five years is a direct result of improvedequipment and processes, new and better materials,new applications, and decreased production costs,enabling the PM route to be more competitive.

The world production of specialty PM steels byHIPing can be estimated for 2008 and forecast for2013, Table I.

For metals, how do the mechanical properties of HIPed PM parts compare withthose of cast or wrought products?The mechanical and functional properties ofHIPed PM metal parts are generally superior to

those of cast parts, if the latter have the samechemical composition and have been heat treatedin the same way as the HIPed PM parts. The castparts contain defects such as inclusions, small

Volume 45, Issue 4, 2009International Journal of Powder Metallurgy

CONSULTANTS’CORNER

9

*PM Technology AB, Global PM Consultants, Drottning Kristinas Vag 48, S-114 28 Stockholm, Sweden; E-mail: [email protected] and Associate Professor, Royal Institute of Technology, Stockholm, Sweden

OLLE GRINDER*Q

A

QA

TABLE I. FUTURE WORLD PRODUCTION OF HIPedSPECIALTY STEELS

Tons2008 2013

High-Speed Steels (HSS)and Tool Steels* 18,000 25,000 Stainless Steels** 5,000 10,000

*Billets, semi-finished products (bars, tubes)**NNS products

CONSULTANTS’ CORNER


cracks, residual porosity, and often segregation.The extent and the negative effects of these imper-fections vary from case to case and from metal tometal.

The HIP manufacture of NNS parts and semi-finished products exhibits several inherent advan-tages from a material perspective:

• A fine and homogenous microstructure• No segregation, which is important in carbide-

rich steels such as HSS and tool steels• Isotropic properties These microstructural advantages lead to an

improvement in both the mechanical and function-al properties of HIPed metals compared with thoseof cast metals of the same shape and composition.An important benefit of the HIPed metals is that,being isotropic, they can be subjected to qualitycontrol (QC) by ultrasonic testing.

It is well known that, frequently, the functionalproperties of PM steels manufactured by HIPingsurpass those of conventional steels. HIPed high-alloy duplex stainless steels have, in some cases,exhibited improved corrosion resistance as a directresult of the fine, homogenous microstructure. Ithas been reported that the risk of hydrogen-induced stress cracking (HISC) in subsea equip-ment can be eliminated by using a HIPed duplexstainless steel. Another, well-known example is theexcellent performance of PM HSS in cutting opera-tions. However, the negative effect of an inferiormicrostructure in cast metals can be reduced bysubsequent hot- and cold-forming operations. Thisis especially effective in carbide-rich HSS and toolsteels.

Of utmost importance is the fact that the HIPconsolidation of inert-gas-atomized powders canbe used in the development of new alloy systemswith unique chemical compositions, microstruc-tures, and functional properties. These alloys can-not be manufactured by conventional casting +forging due to their high alloy content, whichresults in segregation problems, or because ofthermodynamic restrictions. Some examples ofnew PM base-alloy systems are:

• Nitrogen-alloyed HSS and tool steel grades• Development of application-specific grades

with improved wear and corrosion resistance• High-temperature corrosion-resistant steels• Compound metal systems• Composite and dispersion-hardened alloys

Is there a preferred material for the punch-es in the compaction of soft magneticparts? The compaction pressure needed todensify to 7.30 g/cm3 is ~800 MPA.I refer to what I wrote in the “Consultants’Corner” two years ago (Int. J. of Powder

Metallurgy, 2007, vol. 43, no. 5, pp. 11–14) in rela-tion to the choice of tool-steel grades in order tomaximize tool life and to minimize tooling costs.

A number of parameters have a decisive influ-ence on the choice of tooling material; theseinclude:

• The shape of the part to be produced (will thetooling parts have thin sections, chamfers, orsharp corners?)

• Tolerances • Number of parts to be produced• Compaction pressure• Powder grade, e.g., tendency for the powder to

clad on the tool material• Mechanical and functional properties of the

tool steel or cemented carbide such as wearresistance, hardness, toughness, and machin-ability

• Material costsThus, the direct answer to your question is No.When you want to choose a tool steel, it is often

logical to begin with an analysis, based on previ-ous experiences, of the potential failure mecha-nism(s) of the punches while in operation (e.g., therisk of cracking), plastic deformation, abrasive/adhesive wear, or galling.

The next step is to choose a tool steel based onavailable data on the mechanical properties (hard-ness and toughness) of the steel. Two importantfigures are presented in the cited article and theserelate impact energy to the hardness of the steel,and abrasive-wear resistance to hardness. Thesefigures provide a guide on how to select your toolsteel.

Readers are invited to send in questions for future issues. Submit your questions to: Consultants’ Corner, APMI International, 105 College Road East, Princeton, NJ 08540-6692; Fax (609) 987-8523; E-mail: [email protected]

Q

A

ijpm


2009 FELLOW AWARD RECIPIENT

The award was presented at PowderMet2009 in Las Vegas, Nevada.

Animesh has made important contributions and iswidely recognized for his innovative work in materialsprocessing. Having dedicated more than 25 years to thePM industry, he is internationally acknowledged forhaving helped spread the technology of powder injectionmolding (PIM) globally through licensing and technologytransfer activities. He is also recognized for his contributions in alloy development, especially refractorymetals, carbides, hardmetals, intermetallic compounds,and other advanced materials.

Animesh completed his BTech in Metallurgical Engineering and PhD in Engineering(Powder Metallurgy) from Indian Institute of Technology, Kharagpur, in 1982. He isPresident and CEO of Materials Processing, Inc., a company he co-founded in 1999 that isinvolved in PIM of hardmaterials, cermets, and advanced ceramics. His journey to NorthAmerica commenced as Visiting Scientist, Rensselaer Polytechnic Institute, in 1985. Hehas been much traveled in his career including executive positions with ParmatechCorporation (director of R&D), Powdermet (executive VP), and Advanced MetalworkingPractices, LLC (general manager).

A member of APMI for over 23 years, Animesh is a past member of the APMI Board ofDirectors. He has served as co-chairman for several international conferences including 6MPIF conferences on tungsten, refractory, and hardmaterials. He has also been a memberof numerous technical program committees. Animesh has published over 115 technicalpapers, and authored/co-authored several books, including Injection Molding of Metalsand Ceramics. He is listed as inventor/co-inventor on 8 U.S. patents, 3 of which wereplaced under Government Secrecy Order due to their importance to national security. He is a member and Fellow of ASM International and a life member of PMAI (India).

A prestigious lifetime award recognizing APMIInternational members for their significant

contributions to the society and their high level of expertise in the science, technology, practice,

or business of the PM industry

INTERNATIONAL

ANIMESH BOSE


OUTSTANDINGPOSTER AWARD

SOLID LUBRICANT–INFUSED TIN BRONZE–BEARING MATERIALSPRODUCED BY POWDER METALLURGY

Gregory A. Vetterick, Iver E. Anderson, and D.J. SordeletIowa State University, Ames Laboratory

Ames, Iowa

OUTSTANDING POSTER AWARD


The International Journal of Powder Metallurgy would also like to recognize the Posters of Merit from PowderMet2009:

Effect of WC Particle Size on Microstructural and Mechanical Properties of WC-Reinforced Al Metal MatrixCompositesAhmet U. Söyler, Hasan Gokce, Mustafa L. Ovegoglu and Burak Ozal, Istanbul Technical University

Effects of Hot Deformation on Aluminum–Silicon Powder Metallurgy AlloysWinston G. Mosher, W.F. Caley, G.J. Kipouros and D. Paul Bishop, Dalhousie University and Ian W. Donaldson, GKN Sinter Metals

Comparison of Fatigue Resistance of Green-Machined Components vs. Components Machined After SinteringAlexandre Bois-Brochu and Bernard Tougas, Université Laval


GRAND PRIZE WINNERSThe five parts selected as the Grand Prize winners are shown in

Figure 1.The Grand Prize in the automotive—engine category goes to

Capstan, Inc., Carson, California, and its customer Jacobs VehicleSystems, a division of Danaher, Bloomfield, Connecticut, for a PMsteel manifold, Figure 2, assembled with a solenoid into the valve trainof a heavy-duty diesel I-6 truck engine. The part assists with the acti-vation of the “Jake Brake” system inside the engine cylinder head dur-

Winners of the 2009 PowderMetallurgy DesignExcellence AwardsCompetition, sponsored bythe Metal Powder IndustriesFederation (MPIF), wereannounced atPowderMet2009, the 2009International Conference onPowder Metallurgy &Particulate Materials.Receiving grand prizes andawards of distinction, thewinning parts are outstand-ing examples of powdermetallurgy’s (PM) precision,performance, complexity,economy, and innovation.The winning parts showhow customers from aroundthe world are taking advan-tage of PM’s remarkabledesign advantages. In addi-tion to traditional marketssuch as automotive and lockhardware, PM is expandinginto fiber optics, militaryproducts, and industrialapplications.

2009 PM DESIGNEXCELLENCE AWARDSCOMPETITION WINNERSPeter K. Johnson*

DESIGN EXCELLENCEAWARD WINNERS

*Contributing Editor, International Journal of Powder Metallurgy, APMI International, 105 College Road East, Princeton, New Jersey 08501-6692,USA; E-mail: [email protected]

The awards were presentedat PowderMet2009 in LasVegas, Nevada.Figure 1. Grand Prize winners


ing the exhaust cycle, reducing horsepower andperforming a braking action to slow the vehicle.Made to a minimum density of 6.7 g/cm3, themanifold has a minimum yield strength of 345MPa (50,000 psi) and an ultimate tensile strengthof 414 MPa (60,000 psi). Its complex design fea-tures include the variation in thickness levels andcylindrical radius. Secondary operations includemachining the solenoid bore and two port holes.The PM process provided an estimated 20% costreduction over the alternative casting process.

ASCO Sintering Co., Commerce, California,received the Grand Prize in the hardware/appli-ances category for a lockset retractor assembly,Figure 3. made for Best Access Systems–StanleySecurity Solutions, Indianapolis, Indiana. ThePM steel assembly functions as the heart of themechanism in a heavy-duty door lockset system.Its “3D puzzle” design of two identical halves notonly satisfied various functional force-transfermodes and geometry requirements, but allowedASCO to partner with equipment suppliers todevelop a pick-and-place “green” stage assemblyfrom two consecutive parts that allowed the cus-tomer to remove an entire riveting sub-assemblyline at an annual cost savings of $250,000. The“single jaw” design easily withstands therequired 2,222 N (500 lbf) load and meets anaxial pull requirement. Made to a net shape, theassembly has a density of 6.7 g/cm3, 414 MPa(60,000 psi) tensile strength, 862 MPa (125,000psi) transverse rupture strength, a fatigue limit of159 MPa (23,000 psi), and 73 HRB hardness.

FMS Corporation, Minneapolis, Minnesota,and its customer Team Industries, Bagley,Minnesota, have earned the lawn & garden/off-highway Grand Prize for an assembly of five com-plex PM steel parts (two shift forks, two sectorgears, and a park pawl) that go into an all-terrain

vehicle transmission, Figure 4. The sector gearshave AGMA Class 6 splines. Four of the parts aremade from PM sinter-hardened steel to a densityof 7.2 g/cm3 and have a minimum ultimate ten-sile strength of 759 MPa (110,000 psi). One sectorgear, a net shape, is made from 4300 steel andhas a tensile strength of 1,103 MPa (160,000 psi)and a 30 HRC minimum hardness. The otherparts require only minimal machining for featuressuch as the integrated pins, undercuts, anddimensional qualification on one of the shifttracks. The customer saved an estimated 60% bychoosing PM over machined parts.

2009 PM DESIGN EXCELLENCE AWARDS COMPETITION WINNERS

Figure 2. Manifold

Figure 3. Lockset retractor assembly

Figure 4. ATV transmission sector gears, shift forks, and park pawl


FloMet LLC, Deland, Florida, won the handtools/recreation category Grand Prize for a 316Lstainless steel compressed-air nozzle, Figure 5,made for Silvent AB, Borås, Sweden. Fabricatedby the metal injection molding (MIM) process, thehollow nozzle consists of top and bottom halvesthat are molded separately and then joinedtogether into one piece during debinding and sin-tering. The nozzle’s air-flow capacity is tightlycontrolled to ensure optimum use of compressedair as well as to comply with U.S. and EuropeanUnion machine device noise regulations. It canwithstand high ambient temperatures and corro-sive environments, and meets hygienic require-ments of the food processing industry. Thecomplex part has a density of more than 7.6g/cm3, an ultimate tensile strength of 517 MPa(75,000 psi), yield strength of 172 MPa (25,000psi), a 50 percent elongation, 67 HRB hardness,and Charpy impact energy rating of 190 J (140ft.·lbf). After sintering, the seams where the twosections join together are laser welded for a leak-free seal. Significant cost savings result from theelimination of scrap, machining, and secondaryoperations.

Advanced Materials Technologies Pte Ltd.,Singapore, won the Grand Prize in theelectrical/electronic components category for a17-4 PH stainless steel MIM flagstaff nose or EMInose shield, Figure 6, which serves as an externalconnector for a high-performance fiber-optic mod-ule. The part has a density of 7.5 g/cm3, a tensilestrength of 897 MPa (130,000 psi), a yieldstrength of 731 MPa (106,000 psi), an eight per-cent elongation, and a 27 HRC as-sintered hard-ness. The intricate one-piece design would havebeen almost impossible to produce by any manu-

facturing process other than MIM. Secondaryoperations are limited to coining on the two latch-es and the application of a 0.5 µm gold coating forappearance and corrosion resistance. SpecifyingMIM gave the customer an estimated 40% costsavings.

AWARDS OF DISTINCTIONFour parts were selected for Awards of

Distinction, Figure 7.


Figure 5. Air-flow nozzle

Figure 6. Flagstaff nose

Figure 7. Award of Distinction winners


PMG Indiana Corporation , Columbus,Indiana, won the Award of Distinction in the auto-motive—engine category for three high-precisionPM steel parts—slide, housing, and rotor, Figure8—which operate in oil pumps in new largerhybrid SUVs. Choosing PM improved the oilpump’s efficiency in addition to reducing energyconsumption and lowering vibration. The vari-able-displacement vane pump delivers oil whenneeded on demand, eliminating unnecessary oilflow. All three parts are made to a net shape andonly require double-disk grinding for maintainingthickness and flatness tolerances. The parts havea density range of 6.5 g/cm3 for the housing, 6.6g/cm3 for the slide, and 6.8 g/cm3 for the rotor.They are made on an automated compacting–sin-tering–sizing flow line because of their complexityand fragility.

Porite Taiwan Co. Ltd., Taiwan, won theAward of Distinction in the hardware/appliancescategory for a copper-infiltrated PM steel weightbalance, Figure 9, used in a new compact com-pressor and manufactured for Taiwan HitachiCo. Ltd., Taiwan. Made to a density of more than7.2 g/cm3, the multi-level part has a tensilestrength of 600 MPa (87,000 psi), a yield strengthof 414 MPa (60,000 psi), and an 80–85 HRB hard-

ness range. The complicated final shape wasachieved by additional machining. Choosing PMover casting or machining provided a cost savingsof more than 70%.

Parmatech Corporation, Petaluma, California,captured the Award of Distinction in the handtools/recreation category for a MIM 420 stainlesssteel housing block used in a 45-caliber handgun,Figure 10. It contains the firearm’s spring mecha-nism and provides sliding action with othermechanical parts. The complex MIM part featureswings, undercuts, through-holes and blind holes,as well as thin and thick cross sections. Formedto a final density of 7.7 g/cm3, the part has a ten-sile strength of 1,800 MPa (261,000 psi), a yieldstrength of 1,503 MPa (218,000 psi), and a hard-ness range of 48–52 HRC. Choosing the MIMprocess offers a very significant savings overmachining.


Figure 8. SUV engine oil-pump components

Figure 9. Weight balance

Figure 10. Handgun housing block

e-mail: [email protected] web: www.acupowder.com

901 Lehigh Ave., Union, NJ 07083 908-851-4500, • Fax 908-851-4597

6621 Hwy. 411 So., Greenback, TN 37742 865-856-3021 • Fax 865-856-3083

ISO 9001 CERTIFIED ISO 14001 CERTIFIED

must beearnedmust beearned

For 90 years, ACuPowder has been delivering the finest quality powders and

the most conscientious service. Our customersknow that serving their needs and solving their

problems is our highest priority.

Bring us your toughest assignments. We want to earn your trust, too.

The finest powders are from ACuPowder: Copper,Tin, Bronze, Brass, Copper Infiltrant, BronzePremixes, Antimony, Bismuth, Chromium,

Manganese, MnS+, Nickel, Silicon, Graphite and P/M Lubricants.

TRUSTTRUST2009 PM DESIGN EXCELLENCE AWARDS COMPETITION WINNERS

Megamet Solid Metals Inc., Earth City,Missouri, received the Award of Distinction in theaerospace/military category for a handle bodyand yoke made by the MIM process for its cus-tomer, Colt Canada Corporation, Kitchener,Ontario, Canada. Made from 4140 low-alloy steelto a density of 7.4 g/cm3, the parts are core com-ponents in a folding-front-grip assembly thatattaches to the Picatinny Rail System used onmodern military rifles, Figure 11. Challenges pre-sented by the geometric complexity of the partsare efficiently and cost-effectively solved by theMIM process. The parts are sintered in a nitrogenatmosphere followed by post-sintering operationsthat include coining, reaming, and tapping. Thecomponents are quenched and tempered to a45–50 Rockwell C hardness range. Parts are sup-plied to the customer with a manganese phos-phate finish.

The awards were presented duringPowderMet2009 held in Las Vegas, Nevada, June28–July 1, sponsored by MPIF and APMIInternational. Past winners of the MPIF PMDesign Excellence Awards Competition can beviewed at www.mpif.org/designcenter/designcen-ter.asp?linkid=11.


ijpm

Figure 11. Rifle handle components


ALEXANDRE BOIS-BROCHULaval University,Quebéc City, Quebéc,Canada

It was most interesting to attend PowderMet2009and I would like to thank the Scholarships andGrants Committee of the Center for PowderMetallurgy Technology (CPMT) for a CPMT/ AxelMadsen Conference Grant. I would also like tothank my supervisor Professor Carl Blais for hissupport in the preparation of my poster. The firstthing I noted about PowderMet2009 is that it wasa great networking event. Representatives from allsectors of the powder metallurgy (PM) industrywere at the conference, either to present theirresults (thus maximizing the sharing of knowl-edge), or to promote a product. All of the confer-ence attendees had the opportunity to learn aboutadvances in PM, be they scientific or technologi-cal. This was impressive since it was my firstinternational conference.

PowderMet2009 was held in Las Vegas, a city inwhich everything is greater than reality. I arrivedon Friday, June 26, and my fellow students and Ihad time to visit parts of the city. Seeing theshows in front of the hotels, such as the volcano,and standing in the casinos was something spe-cial. The city is much more grandiose than is por-trayed in the movies.

The technical sessions in which I assisted pro-vided invaluable information that I will usethroughout my career. The value of this confer-ence was the variety of PM technologies that werediscussed. There were many captivating subjects

AXEL MADSEN/CPMT SCHOLARREPORTS

Axel Madsen/CPMT Conference Grants are awarded to deserving students with a serious interest in PM. The recipients were recognized at theIndustry Recognition Luncheon during PowderMet2009.

and, even though I planned my schedule careful-ly, I was forced to miss several concurrent techni-cal sessions. Of particular interest were thesessions on sinter hardening and titanium. In theformer, I learned about optimizing alloy composi-tion to obtain enhanced mechanical properties.The titanium sessions provided a completeoverview of the technology of PM titanium andattendant market possibilities.

In conclusion, I would like to reiterate thatattending PowderMet2009 was a great opportuni-ty. I had the chance to learn extensively aboutPM, and to develop new contacts that will be use-ful during my career.

ANDREW CHANDrexel UniversityPhiladelphia,Pennsylvania

I had never been to Las Vegas before and the heatwas a new experience; it soaked through myclothes but the dry heat was not particularlyuncomfortable. I arrived at The Mirage hotel and,after a long check-in process, I managed to settleinto my room. Afterwards I went downstairs to theconference area to register and set up my poster. Ireturned to my room to change into more casualclothes and went downstairs to the welcomingdinner. The dinner was fantastic with deliciousfood and plentiful beverages along with a dolphinpool as a backdrop. There was also Sigfried andRoy’s Secret Garden which housed a collection oflions and tigers adjacent to the dinner area. It was

PERSONALINSIGHTS

AXEL MADSEN/CPMT SCHOLAR REPORTS


great being able to chat with members of the PMindustry in a casual setting. I left the dinner areaand explored the casino before going to bed.

While enjoying breakfast, I looked over theConference Guide to select the presentations thatI wanted to attend. I attended the technical ses-sions on compaction processes and stainless steelsurface modification. After these sessions Iattended the Industry Recognition Luncheon andwas formally recognized for receiving aCPMT/Axel Madsen Conference Grant. The lunch-eon was great and I was able to converse with myfellow grant recipients, along with PM industrymembers and several Drexel University alumni.

Las Vegas is an eccentric city, to say the least. Iwalked in and out of several casinos to take in thesights. I regret not bringing my camera to takephotographs, but what I do not regret is taking acab to the “In and Out Burger” to enjoy a smallcelebratory dinner using my casino winnings. Iwish I had made it to one of my classmates’ pres-entation on pharmaceutical powder compactionbut was attending another session.

I would like to thank the Scholarships & GrantsCommittee of the Center for Powder MetallurgyTechnology (CPMT) for this award. It was eyeopening and informative to see the work on PMbeing conducted around the world and to seewhat engineers were really up to. Once again, Iam grateful for the grant and the experience itoffered me.

JENNIFER WALTERSArizona State UniversityTempe, Arizona

Although I have visited Las Vegas, Nevada, manytimes before, my trip in June 2009 was differentfrom those of the past. As always, I wasimpressed by the vastness of the strip, the archi-tecture of the hotels, and the throngs of peopleeverywhere, despite the heat—and the economy!

But this particular visit created a new sense ofexcitement in me. I was excited as to what I mightlearn and whom I might meet at PowderMet2009.

As this was my first professional conference, Iwas unsure what to expect. The opening nightevent in The Mirage’s Dolphin Habitat was a greatkick-off. The atmosphere was inviting, and I quick-ly learned that the PM industry is a tightly net-worked group with many members spending themajority of their careers in PM. It was great to seestanding friendships amongst the attendees fromdifferent companies and sectors of the industry.

During Monday’s keynote address, I was inter-ested to learn how closely the PM and automotiveindustries are tied. Despite the uncertain econom-ic climate, the atmosphere was surprisingly posi-tive. This was further evidenced by the conferenceattendance, though lower than usual. Thekeynote address reinforced the many opportuni-ties for PM developments in the future.

From the technical sessions, I began to appreci-ate the breadth of research occurring in PM.Though many of the sessions interested me, Ichose to attend those pertaining to my research.While the presentations were oftentimes quitespecific, the speakers were adept at concisely con-veying their research results and observations insuch a way that both novices, such as me, andexperts could benefit. I particularly enjoyed thefriendly debate on defining “cooling rate” duringthe sinter hardening sessions.

Over the course of the conference, I was contin-ually impressed with the PM community. Duringthe technical sessions and the social events, Iinteracted with people from many countries andfrom many areas of PM. The common thread thatI observed many times was that the PM communi-ty is passionate about their work and the oppor-tunities available in the field. The industry is bothinviting and exciting to a newcomer like me.

PowderMet2009 was an incredible experiencefor me. I am now revived for a return to myresearch and to contribute to the field. I wouldlike to thank the Scholarships and GrantsCommittee of the Center for Powder MetallurgyTechnology (CPMT) for a CPMT/Axel MadsenConference Grant and my research advisor,Professor Nikhilesh Chawla, for affording me theopportunity to attend the conference.


AXEL MADSEN/CPMT SCHOLAR REPORTS

GREGORY VETTERICKIowa State UniversityAmes, Iowa

I landed in Las Vegas a few days beforePowderMet2009 to the sound of rain on the tarmac.Water falling from the sky was most certainly notwhat I had expected toward late June in the Nevadadesert. It stuck with me through trips to the HooverDam and the Grand Canyon. As the conferenceapproached, however, the sun and heat returned.My trek in the hot sun (I regret the decision not totake a cab) from my original hotel to The Miragewas well rewarded. I was impressed with the clean-liness and upscale appearance of the hotel.

The opening night event in the Dolphin Habitatwas not only a great way to beat the heat, butalso a useful way to meet many of the faces in thePM world. In what seemed like a very short time, Iwas introduced to many people, some of whom Ihave consulted with or referenced while workingtoward my degree. It was comforting to be wel-comed so warmly and to be accepted into such atight-knit group.

For me, these social events—including theopening night event, luncheons, the main socialevent, and the industry trade exhibition—were

important components of the conference. Each ofthese functions allowed me to meet people fromthe companies and universities involved in PM. Iwas also able to understand what they do, and insome cases discover that they are very good at it,as exemplified at the Industry RecognitionLuncheon. The insight gained at the conferencewill prove invaluable as I near the end of myMaster’s work.

The technical portion of the conference wasinformative in its own right. I attended many pre-sentations on a variety of subjects throughout theconference. I was impressed with the SpecialInterest Programs. The sessions on PM titaniumgave an excellent summary of the current technol-ogy and expected future developments. Presentingmy first technical paper at PowderMet2009, inaddition to my poster, was an honor. Having akind, helpful audience was encouraging and madeit an enjoyable experience.

I am grateful that I was given the opportunity toexperience PowderMet2009. Receiving a CPMT/Axel Madsen Conference Grant afforded me theopportunity to attend. Without this grant, myindustry-sponsored research would have madetravel to the conference difficult in this slow econo-my. Having the opportunity to be recognized for myposter, networking at the conference, and learningmore about the PM industry was exceptional. I feelthat the CPMT/Axel Madsen Conference Grantdoes exactly as intended, namely, “to encouragestudents to learn more about PM technology andeventually pursue careers in the PM industry.” ijpm


THE BROAD PICTUREIHS Global Insight, an economic forecasting organization, reports

that most manufacturing surveys are beginning to show signs of stabi-lization, but also a very sharp reduction in inventories, which is driv-ing production lower. It expects that inventory adjustment in thesecond half of 2009 will become less turbulent. Nevertheless, overallmanufacturing production in the U.S. is expected to drop 12%, itsworst decline since 1946, followed by a small improvement next year.Many in the PM industry say we have finally hit the bottom but dis-agree about how long the bottom will last.

However, we should never forget that the PM industry was built dur-ing difficult times. Many of the early pioneers and entrepreneurs gottheir start during the Great Depression. Their spirit of innovation,hard work, and grit overcame mountains of obstacles in the years thatfollowed. That same spirit is still alive today, and will hopefully sustainthe industry during these current difficult times.

2008: A YEAR REVIEW2008 was a painful year. We found ourselves in a declining industri-

al market and the beginning of an inflationary spiral. The PM businessyear began on a hopeful note but weakened in the second half, espe-cially in the final quarter. This was due primarily to a sharp decreasein automotive production in November and December.

The significant hikes in commodity prices, oil, and labor costsplayed havoc with our bottom lines. In addition, production in generaldeclined significantly, with durable goods orders off and vehicle pro-duction down 16%.

Metal powder shipments remain the most accurate barometer forour industry’s health. In 2008, iron powder shipments declined 19% to296,901 mt (327,272 st), with the PM parts share off by almost 22% to258,513 mt (284,957 st), Figure 1. Copper and copper-based powdershipments declined 13% in 2008 to15,785 mt (17,400 st), with the PMsegment declining 10.5% to 13,473 mt (14,851 st), Figure 2. We esti-mate that stainless steel powder shipments declined about 20% lastyear to 7,031 mt (7,750 st). We also estimate that total metal powdershipments in North America declined 18.4% to 376,875 mt (415,427st), Table I.

We can view the currentstate of the powder metal-lurgy (PM) industry throughshort-term fear-tinted glasses or as long-rangeopportunities. Just like U.S.manufacturing in general,the PM industry has beenimpacted negatively by thecurrent U.S. recession, sinking real estate prices,the banking crisis, plungingautomotive production, andhigh unemployment (9.4%nationally in May and over15% in St. Marys). Theseeconomic events, unprece-dented in modern times, aretesting the consumer publicand corporations alike.

STATE OF THE PM INDUSTRY IN NORTH AMERICA—2009 Mark Paullin*

ENGINEERING &TECHNOLOGY

*President, MPIF, and President, Capstan, 16100 S. Figueroa Street, Gardena, California 90248, USA; E-mail: [email protected]

Presented at PowderMet2009in Las Vegas, Nevada.


In contrast, European PM-grade iron powdershipments fell 11.2% to 177,071 mt (195,184 st)and copper and copper-based shipments dropped17% to 11,863 mt (13,077 st). In Japan, total ironpowder shipments declined about 1% in 2008 to225,861 mt (248,965 st), and copper powder ship-ments declined 4% to 8,573 mt (9,450 st).

2009 OUTLOOK Unfortunately, North American iron and copper

shipments continued deteriorating in the first half

of 2009, impacted severely by the sharp decline inlight-vehicle production as well as the shift awayfrom large cars and SUVs to smaller cars withfour-cylinder engines. Through May 2009, ironpowder shipments declined 44%.

From a national economy point of view, therewas also a significant decline in industrial pro-duction as the durable goods market collapsed.The only hope for the powder market is an expect-ed spike in production beginning in September,driven by a positive change in the automotive andhome building markets. Several PM industryobservers anticipate an improvement in the fourthquarter, and we hope they are right.

We do have some good news in commodityprices, which have declined drastically from thehyper-inflationary numbers experienced duringthe summer of 2008: remember the pain of$1.06/L ($4.00/gal) gasoline, $150/barrel oil,$882/mt ($800/st) steel scrap, $55/kg ($25/lb.)nickel, and $8.8/kg ($4.00/lb.) copper? While ris-ing somewhat, steel scrap is currently in the$495/kg to $550/kg ($225/lb. to $250/lb.) range,copper seems to be settling in the $5.1/kg to$5.5/kg ($2.30/lb. to $2.50/lb.) range and nickelis well below $22/kg ($10/lb.). This softening ofcommodity prices has certainly helped both ourcash flows and our bottom lines.

North American vehicle production plunged 45percent in May, the third lowest month in thepast 18 according to Automotive News, with U.S.production accounting for a 51.6% decline.Through June, the annualized production rate is7.2 million vehicles. Early estimates put the totalyear’s production at 8 million vehicles, a 36%drop from the 12.6 million produced in 2008 anda 46% drop from the 15 million vehicles manufac-tured in 2007.

A correlation between North American light-vehi-cle production and iron powder shipments since2002 puts things into stark perspective, Table II.

STATE OF THE PM INDUSTRY IN NORTH AMERICA—2009

Figure 1. North American iron powder shipments (1 st = 0.9072 mt)

Figure 2. North American copper and copper-base powder shipments (1 st = 0.9072 mt)

TABLE I. NORTH AMERICAN METAL POWDER SHIPMENTS*

2007 2008

Iron & Steel 404,650 327,272Stainless Steel 9,676 (E) 7,750 (E)Copper & Copper Base 19,992 17,400Aluminum 50,000 (E) 42,500 (E)Molybdenum 2,800 (E) 2,000 (E)Tungsten 4,650 (E) 4,000 (F)Tungsten Carbide 7,394 5,103 Nickel 9,190 (E) 8,650 (E)Tin 785 752

(E) estimate 509,137 st 415.427 st*(1 st = 0.9072 mt)

TABLE II. NORTH AMERICAN VEHICLE PRODUCTION

Vehicle Production (millions) Iron Powder Production (st)* Change (%)**

2009 8.0 (estimated) 215,000 (projected) -342008 12.6 327,272 -192007 15.0 404,649 -32006 15.2 416,828 -52005 15.7 439,090 -72004 15.7 473,804 —

*1 st = 0.9072 mt **year-to-year change in iron powder production


automotive applications representing more than750 total parts. These are conservative numbers:some estimates put the number at 1,000 or moreparts, taking into account applications not yetidentified.

MPIF will also shortly release the 2009 editionof Standard 35, Materials Standards for PMStructural Parts. The newly updated version con-tains new materials and mechanical property dataand new engineering information on hardenabilityand corrosion resistance. This new informationwill be helpful to automotive design engineers.

New applications exist in advanced transmis-sions such as dual-clutch designs and continu-ously variable transmissions (CVTs), as well as infive- and six-speed transmissions. Europe is wellon its way to unseat the dominance of manualtransmissions, which could open up new PMopportunities in automatics. The trend towardincreasing power in smaller engines with tur-bochargers offers potential applications in theturbo drive system and electric power generatorswhich use high rpm transmissions.

Diesel engines represent another potentialgrowth market for PM parts, especially for pow-der-forged connecting rods and high-alloy PMmaterials. Clean diesels offer 30% better fueleconomy and 25% fewer CO2 emissions.

The PM industry must also join the hybridbandwagon or be left behind. The Nikkei BusinessDaily recently reported that the global hybridvehicle market will grow to 11.28 million vehiclesby 2020. Potential applications in hybrids includeelectric traction drives and electric motor gears.

Finally, structural changes in the NorthAmerican automotive market, with the new GMand Chrysler organizations perhaps, could force anew wave in the consideration of cost savings andinnovative technologies intrinsic to PM. We canonly hope so.

DIVERSIFY OR DIE While the automotive market will still be impor-

tant for the PM industry, diversification into newmarkets is vital for our future. Renewable “green”energy presents opportunities for conventionalPM, metal injection molding (MIM), and nanotech-nology. Wind turbines use electric motors andtransmissions that need metal parts and bear-ings. For example, bearings in wind turbines arenoted for their high maintenance requirements: isit possible to make high-performance full-density

The big questions are, “When will the domesticautomotive market rebound, and will there still beparts suppliers in business when it does?” We cansay with confidence that those suppliers leftstanding will be leaner, stronger, better financed,and better prepared to compete in the global mar-ketplace. Those suppliers will be able to serve thegrowing industrial and automotive markets inNorth America.

CSM Worldwide, a well-known internationalautomotive forecaster and consulting organiza-tion, forecasts global light vehicle production toexceed 78 million vehicles by 2015, a 50%increase from the 52 million vehicles slated to beproduced in 2009, Table III. The forecast forgrowth in North America is still robust. Of theseven geographic regions, North America has thehighest projected increase of vehicle productionand is number two in percentage increase.

Taking this figure, we can project the averageestimated PM usage to range anywhere from 6.8kg to 10.5 kg (15 lb. to 23 lb.) globally, whichtranslates into a potential global PM automotivemarket of somewhere between 535,248 mt and816,480 mt (590,000 st and 900,000 st). Theaverage PM content in North American vehicles isexpected to remain at about 18.6 kg (41 lb.) pervehicle. North American PM companies must posi-tion themselves globally to capture a major shareof this market.

The PM industry still has much to offer carmanufacturers in conventional powertrains, indiesel engines, and in hybrids. We can offer inno-vative engineering/materials solutions, cost sav-ings, and a technology that is, for the most part,environmentally safe. For example, the MetalPowder Industries Federation (MPIF) has justreleased the PM Automotive Parts Catalog studythat has already identified more than 300 PM


TABLE III. CSM LIGHT-VEHICLE PRODUCTION FORECAST*

2009 2015 Increase (%)

China 8.0 11.6 45Europe 15.8 21.7 37Japan/Korea 10.7 14.6 36Middle East/Africa 1.6 2.5 56North America 8.2 14.6 78South America 3.4 5.3 56 South Asia 4.5 8.3 84

52.2 78.6 50

*Units in millions


PM bearings? Solar power is still another growingmarket for commercial and consumer applica-tions.

MIM remains a bright spot that serves diversemarket segments such as medical, dental, andelectronics applications. One observer suggeststhat quick-change tooling could open up newautomotive applications by helping MIM partsmakers compete more successfully with invest-ment casting.

To further promote MIM’s advantages to thedesign community, the Metal Injection MoldingAssociation (MIMA) this year launched a dedicat-ed Web site devoted to the benefits of using theMIM process. Visit www.mimaweb.org.

Still in their infancy, rapid prototyping and rapidmanufacturing are exciting technologies ready tohit the commercial production scene. There areseven companies worldwide that make machinesthat use metal powders. It is estimated that 100such machines are in use, with about 50% of themat academic institutions. However, a company inEurope is producing 10,000 hip replacement cupsannually via rapid manufacturing.

Nanotechnology is another promising area.According to a recent report in The Economist,MIT researchers have developed a nickel–tungstenalloy as a substitute for chrome plating. Addingtungsten to nanocrystalline nickel produces ahard material capable of being plated but moreenvironmentally friendly than chrome. Tests areunderway with the alloy on truck bumpers.

SUSTAINABILITY—NOTHING NEW TO PMGreen is hot. Products and manufacturing

processes that promote green products and envi-ronmentally sensitive material, that are non-pol-luting, and that conserve energy and naturalresources are economically sound. PM is a sus-tainable, net-shape manufacturing process thathas long been recognized as a green technology,for minimizing energy consumption and for recy-clability. Metal powders are produced from recy-

cled materials and most PM parts can be recycled.But we have not done a good job in promotingPM’s sustainability story.

This is about to change. MPIF is coordinating anew effort to promote PM’s sustainability. It is fea-tured in a new promotional campaign planned forrelease later this year or early next year. The cam-paign will include a new “PM Green Technology”logo to be used in advertisements, on membercompany material, boxes, letterheads, etc. Therewill be more details to come on this campaign.

INVESTING IN NEW TECHNOLOGY It is gratifying to note that many PM companies

are still investing in new technology. And whenthe marketplace returns to normalcy, thoseinvestments will reap rewards.

Metal powder suppliers are working on newmaterials to increase densities to 7.5 g/cm3 withsingle pressing (SP) and single sintering (SS). Theyare also aiming R&D at providing lower-cost alter-native materials to replace diffusion-bonded pow-ders and high-nickel grades. Specialty-powdermakers are developing cleaner prealloyed iron-,nickel-, and cobalt-base powders for high-per-formance parts. We must move beyond plain ironpowder to meet the demand for high-temperaturematerials that will open new markets. Copper-powder makers are also diversifying into extra-fine spherical powders for electronic applications.Green bullets, antimicrobial products, and anti-fouling paints are niche markets for copper pow-ders that offer additional promise.

While the PM industry faces many challenges,it will still be an important materials technologyand manufacturing process. As the current reces-sion subsides, the market will return and grow.The U.S. automotive and industrial markets willstill need innovative suppliers that offer precisionproducts and cost savings. PM companies thatremain will exit the recession much leaner andstronger and more capable of serving customersin the new economy.


ijpm


INTRODUCTIONin the past decade, a series of new bulk metallic glasses (MGs) with

a multicomponent chemistry and high glass-forming ability (GFA) havebeen developed, including Zr-, Mg-, La-, Pd-, Ti-, and Fe-based alloysystems,(1–4) using various solidification techniques; this has engen-dered interest in the synthesis and application of bulk MGs. In turn,the properties of these bulk MGs, the strength and anticorrosion prop-erties of which are typically superior to those of their crystallinecounterparts, have stimulated researchers to explore techniques tofabricate net-shaped bulk MG components. While some progress hasbeen documented,(5–8) significant breakthroughs have been hinderedby the less-than-optimum GFA and high viscosity that are typicallyassociated with MGs.

Compared with most other MGs, such as Zr- and Pd-based MGs,the advantages of Fe-based MGs include a much lower material costand excellent mechanical and physical properties.(8) The major obsta-cle to forming Fe-based MGs has traditionally been their limited GFA,although some progress has been documented in the literature.(8–11)

The high GFA value of these Fe-based MGs has been rationalized onthe basis of three empirical rules proposed by Inoue et al.:(12,13) (1)multicomponent alloy systems consisting of more than three con-stituent elements, (2) significantly different atomic size ratios, and (3)negative heats of mixing among the constituent elements. It was alsoreported that the addition of Mo increases the GFA of Fe-basedalloys.(11,14) The addition of Mo and W to Fe-based alloys can also

In this article, the laser-engineered net shaping(LENS) process is imple-mented to fabricate net-shaped Fe-based Fe-B-Cr-C-Mn-Mo-W-Zr metallic glass(MG) components. The glass-forming ability (GFA), glasstransition, crystallizationbehavior, and mechanicalproperties of the glassyalloy are analyzed to pro-vide fundamental insightsinto the underlying physicalmechanisms. Themicrostructures of variousLENS-processed componentgeometries are character-ized via scanning electronmicroscopy (SEM), X-ray dif-fraction (XRD), differentialscanning calorimetry (DSC),and transmission electronmicroscopy (TEM). Theresults reveal that the as-processed microstructureconsists of nanocrystallineα-Fe particles embedded inan amorphous matrix. Anamorphous microstructure is observed in depositedlayers that are located nearthe substrate. From amicrostructure standpoint,the fraction of crystallinephases increases with theincreasing number ofdeposited layers, effectivelyresulting in the formation of a functionally gradedmicrostructure with in-situ-precipitated particles in anMG matrix. The microhard-ness of LENS-processed Fe-based MG components hasa high value of 9.52 GPa.

PROCESSING ANDBEHAVIOR OF Fe-BASEDMETALLIC GLASSCOMPONENTS VIALASER-ENGINEERED NETSHAPINGB. Zheng,* Y. Zhou,** J.E. Smugeresky,*** and E.J. Lavernia****

RESEARCH &DEVELOPMENT

*Postdoctoral Researcher, **Associate Researcher, ****Provost and Executive Vice Chancellor, are with the Department of Chemical Engineering andMaterials Science, University of California, Davis, CA 95616, USA: E-mail: [email protected], ***Senior Staff Member, Sandia NationalLaboratories, MS 9402, Dept. 8724, Bldg. 940, Room 1191, 7011 East Avenue, Livermore, CA 94551, USA; E-mail: [email protected]

DOI: 10.1007/sll661-009-9828-y© 2009 The author(s). This article is published with open access at Springerlink.comREPRINTED FROM: METALLURGICAL AND MATERIALS TRANSACTIONS A 1236—VOLUME 40A, MAY 2009


enhance their corrosion resistance.(14–16)

Moreover, adding Zr significantly increases theglass transition temperature Tg, and adding Mndecreases the liquidus temperature and Curiepoint. At the same time, increasing the amount ofB can also enhance GFA.(1) In this study, gas-atomized Fe58Cr15Mn2B16C4Mo2Si1W1Zr1 (at. pct)powder was used for the laser processing of MGcomponents. The other elements (e.g., Cr, B, andSi) enhance thermal stability and provideincreased additional solid solution strengthening.

Gas atomization (GA) is a practical and effectiveapproach for producing MG powder. However, thegas-atomized MG powder cannot be used directlyas a structural component. Accordingly, gas-atomized powder is generally processed through aseries of conventional powder metallurgy stepssuch as degassing, cold isostatic pressing or hotisostatic pressing, and extrusion to form densebulk materials, which are then machined intofinal components. In this article, we explore thepotential of using the LENS process to form fullydense, three-dimensional (3-D) net-shaped Fe-based MG components through laser deposition.Inspection of the technical literature reveals thatthe results obtained for the laser glazing(17–18) andlaser cladding of MGs(19–22) been reported,although these are concerned with surface treat-ments and coatings. To our knowledge, this workrepresents the first time that the fabrication ofnet-shaped bulk MG components has been inves-tigated by laser direct-deposition techniques.

Laser-engineered net shaping (LENS) provides anovel pathway for producing net-shaped bulkMGs. The LENS process is a laser-assisted, directmetal manufacturing process originally developedat Sandia National Laboratories (Albuquerque,NM).(23) The LENS process incorporates featuresfrom stereolithography and laser cladding, using acomputer-aided design file to control the formingprocess; a 3-D part can be generated point bypoint, line by line, and layer by layer via additiveprocessing. The LENS process can produce rela-tively high, localized cooling rates at each deposi-tion point due to the very small size of the meltpool and the conduction of thermal energy intothe substrate.(24,25) Therefore, it should be possi-ble to manufacture net-shaped MG componentsusing LENS, because the material is deposited assequential and cumulative layers. In addition, itshould be possible to optimize the cooling condi-tions for MG processing by controlling the pro-

cessing parameters such as the laser power andtravel speed.

The LENS process provides several advantagesfrom an engineering standpoint. The LENSprocess can be used to generate materials thatcontain multiple length scales, thereby facilitatingthe optimization of physical properties. In thecase of MGs, it should be possible to fabricatenet-shaped components with a high material yieldand attractive physical properties. In this article,Fe-based Fe-Cr-Mo-W-C-Mn-Si-Zr-B MG compo-nents were deposited via LENS processing. Theirmicrostructure was characterized via scanningelectron microscopy (SEM), X-ray diffraction(XRD), differential scanning calorimetry (DSC),and transmission electron microscopy (TEM). Themechanisms thought to be responsible for theobserved microstructure, GFA, and mechanicalproperties are discussed.

EXPERIMENTAL PROCEDURESGas-atomized Fe-based Fe58Cr15Mn2B16C4Mo2

Si1W1Zr1 (at. pct) powder with a size range of 10to 110 µm was selected as the starting material. Ahot rolled 304 stainless steel plate with a thick-ness of 6.35 mm was used as the substrate. TheLENS 750* system used in this study was manu-factured by Optomec, Inc. (Albuquerque, NM) andconsists of a continuous-wave mode Nd:YAG laseroperating up to 650 W, a four-nozzle coaxial pow-der feed system, a controlled-environment glovebox, and a motion control system. The nominallaser beam diameter is 6.3 mm and has a <0.5-mm diameter circular beam waist at the focalzone. The energy density used in the present arti-cle was in the range 2 × 104 to 1 × 105 W/cm2.

Three types of sample geometries were fabricat-ed for our study: shells (A, B, and C), solid cubes(D, E, F, and G), and coatings (H, I, J, and K), asshown in Figure 1, with different process parame-ters shown in Table I. In the case of the coatingand cubic samples, the area of each layer corre-sponded to 10 × 10 mm. The hatch space is 0.38mm and the layer thickness, ∆Z, is 0.25 mm. Thecoating samples were fabricated with differentnumbers of deposited layers (1 for H, 2 for I, 4 forJ, and 8 for K), to investigate the microstructureevolution during laser deposition. Successive lay-ers were deposited with the hatch lines of two

PROCESSING AND BEHAVIOR OF Fe-BASED METALLIC GLASS COMPONENTS VIA LASER-ENGINEERED NET SHAPING

*LENS 750 is a registered trademark of Sandia NationalLaboratories, Albuquerque, NM.


adjacent layers at an angle of 90 deg. The entireprocess was carried out in an Ar environment, toavoid oxidation during deposition. The oxygenlevel in the glove box was maintained below 10ppm during deposition.

The as-deposited Fe-based components weresectioned along the center axis and perpendicularto the laser travel trace on the top layer; they werethen mounted, ground, and, finally, finely pol-ished using the conventional techniques for met-allographic characterization studies. Scanningelectron microscopy coupled with energy-disper-sive X-ray (EDX) spectrum analysis, XRD with CuKα radiation, DSC, and TEM were used for themicrostructure characterization and phase anal-ysis of the deposited samples. The XRD scanswere performed on the free surfaces of the laser-deposited coatings. Microhardness measurementswere conducted using a Vickers indenter withBuehler MicroMet 2004 apparatus (Buehler Ltd.,Lake Bluff, IL) under a 100-g load on metallo-

graphically mounted cross sections of the laser-deposited samples.

RESULTS AND ANALYSISGas-Atomized Powder

The gas-atomized Fe-based Fe-Cr-Mo-W-C-Mn-Si-Zr-B alloy powder exhibited a lognormal sizedistribution. Observations of the powder withSEM secondary electrons revealed that most ofthe powder is spherical in shape, which is typicalfor a gas-atomized powder,(26) with variations inthe surface morphology, as shown in Figure 2(a).The surface of the smaller powder was generallysmoother than that of the larger powder, the asso-ciated roughness being attributed to solidificationshrinkage.(26,27) Moreover, the surface featureswere noted to be indicative of the microstructure:smooth in the case of the amorphous powder andrough in the case of the crystalline powder.

The cross-sectional microstructures of the dif-ferent powder sizes were studied using SEMbackscattered electrons (BSEs) and revealed thetypical microstructure shown in Figure 2(b). Thepowder <20 µm revealed a featureless microstruc-ture, indicating that no crystallization hadoccurred during GA. The featureless powder wasconsidered to be amorphous. The extent ofcrystallization was noted to increase with thepowder size, consistent with publishedresults.(28–30) It is important to note that,although a starting powder with a wide particlesize range (from 10 to 110 µm) and different ini-tial microstructures (from amorphous to crys-talline) was used in this work, all the particles willbe completely melted and resolidified duringLENS deposition. Therefore, the influence of theinitial microstructure of the starting powder onthe microstructure and properties of the laser-deposited layers was deemed to fall outside of the


TABLE I. PROCESS PARAMETERS USED FOR LASER DEPOSITION VIA LENS

Sample Number Laser Power, Travel Speed, Power Exposure, Powder FeedP(W) v (mm/s) P/v (J/mm) Rate (g/min)

Shell A 180 12.7 14.17 10B 280 8.47 33.06 6C 280 12.7 22.05 10

Cubic bulk D 180 12.7 14.17 10E 180 8.47 21.25 10F 296 8.47 34.83 10G 180 4.23 42.55 10

Coating S,T,U, and V 180 12.7 14.17 10

Figure 1. Laser-deposited Fe-based MG samples using LENS


scope of the present study. The primary consider-ations used to select the starting powder weremorphology (i.e., spherical), size (<150 µm), GFA,and laser energy absorption. For the irradiationwith Nd:YAG laser (wavelength 1.06 µm), theabsorptivity of Al (0.06 to 0.2) and Cu (0.04 to 0.3)alloys is much lower than that of Fe alloys (0.25to 0.35).(31)

Microstructure of LENS-Deposited SamplesThe material initially deposited on the cold sub-

strate during LENS experiences a high quenchingeffect; it is in this region that an amorphousmicrostructure is likely to be observed. The mag-nitude of the cooling rate during the first-layerdeposition can be estimated to be 103 to 104 K/son the basis of numerical simulations.(32,33)

Figure 3 shows a micrograph, imaged with SEMBSEs, of an initially deposited layer obtained with

a laser output power of 280 W and a travel speedof 12.7 mm/s. The features of the melt pool shapeand the overlap between subsequent depositedlines are clearly visible. The microstructure is fea-tureless, which suggests that the first layer isamorphous. This indicates that the cooling rateexperienced by the deposited materials was highenough to form an amorphous microstructure,consistent with that reported for these Fe-basedMGs.(19,34) The top surface contained some partlyunmelted particles that retained the original par-tially amorphous structure of the powder, asshown in Figure 3(a). These particles will be com-pletely melted and resolidified during the subse-quent layer deposition, because the surface of thepreviously deposited layer is always partiallyremelted by the laser beam during deposition.Only the surface of the final deposited layer con-


Figure 2. SEM micrographs of gas-atomized Fe-based alloy powder: (a) powdermorphology and (b) powder cross section

(a)

(b)

Figure 3. SEM (BSE) micrographs of first layer of laser-deposited Fc-bascd MGcoating via LENS


tains partly unmelted particles. The presence oflight-colored phases in the second layer suggeststhat melting and resolidification occurred in thisregion presumably under a low cooling rate, e.g.,approximately 102 to 103 K/s.(33,35)

In order to investigate any possible reactions ofthe deposited layer with the substrate, an identi-cal powder was deposited on an amorphous sub-strate using the same parameters as were usedfor deposition on the 304 SS substrate. Similar tothe case of a crystalline substrate, laser deposi-tion on the amorphous substrate made of Fe-based Fe-Cr -Mo-W-C-Mn-Si-Zr -B thickamorphous coatings (400 µm) on a 304 SS platevia high-velocity oxygen fuel thermal spraying(36)

also resulted in overlapping, amorphous meltzones. The absence of microstructural features inthese zones indicates that the region is initiallymelted by the laser beam and then resolidified asglass, regardless of the nature of the underlyingsubstrate. The absence of significant dilution orreaction products at the interface of the depositedFe glass and the 304 SS substrate is attributed tothe high solidification rates associated with LENSprocessing, which suppresses the diffusion-con-trolled phase transformations of crystallizationsuch that solute trapping will occur and large seg-regation no longer operates.

As the thickness of the deposited materialincreases, the microstructure coarsens and pre-cipitation becomes increasingly evident, particu-larly at the boundary of the melt pool region,which, for purposes of this discussion, may be

described as a heat-affected zone (HAZ). Thethickness and morphology of the HAZ stronglydepends on the LENS processing parameters. Thistrend is consistent with the decrease in the cool-ing rate that accompanies an increase in thenumber of deposited layers.

In the case of the LENS-deposited samples withcubic and shell geometries, the macroscale vari-ables that influence deposition are a buildup ofheight and melt depth into the previous layer. Toascertain the results of these samples, metallo-graphic cross sections of the deposited materialswere made. The height buildup was measuredfrom the substrate surface to the upper surface ofthe deposited material. Similarly, the melt depthwas taken to be the depth of the region in whichdissolution is evident. The measured melt depthtends to increase from a minimum value of 0.05mm to a maximum value of 0.25 mm withincreasing laser power and decreasing laser travelspeed. When the laser travel speed is low, there istime for powder accumulation, and slightly morepenetration occurs. In terms of geometrical con-siderations, the laser power and travel speed alsoplayed a significant role in the accumulation andremelting processes. The experimental resultssuggest that there was a strong correlationbetween the height buildup of the materials and aratio defined hereafter as the laser power expo-sure (laser power/laser travel speed). Figure 4shows the variation in the height buildup with thelaser power exposure. The overall thickness of thebulk cubic and shell samples increases withincreasing laser power exposure. The relationshipbetween the height buildup H and the processingparameter P/v was derived using curve-fittingtechniques; it is given as

H = 2.33 + 0.35(P/v) – 0.004 (P/v)2

for bulk geometries [1]

H = 3.48 + 0.14(P/v) – 0.001 (P/v)2

for shell geometries [2]

where P is the laser output power and v is thelaser travel speed. The thickness of the bulkgeometry is larger than that of the shells and canbe attributed to the fact that there is overlapbetween the deposition lines during the fabrica-tion of the former, whereas there is none duringthe deposition of the latter.

The typical microstructure of laser-deposited


Figure 4. Variation on build-up height of materials with laser power exposure


bulk cubic geometry is shown in Figure 5. Thissample was produced with a laser power of 280 Wand a travel speed of 12.7 mm/s. It is evident thatthe microstructure from the top layers is muchcoarser than that present in the bottom layers.The results from this sample confirm that thetemperature of the deposited materials increaseswith thickness during laser deposition, and thatthe cooling rate decreases with increasing dis-tance from the substrate. In addition, the heatgenerated by the subsequently deposited layerscan promote crystallization of the preceding lay-ers. Approximately two layers revealed a feature-less microstructure, which was considered to beamorphous.

Figure 6 shows the microstructure evolution inthe laser-deposited Fe-based MG shell componentprocessed with a laser output power of 280 W anda travel speed of 12.7 mm/s. As one moves fromthe bottom to the top layers, the microstructurevaries from amorphous to an MG matrix compos-

ite, effectively forming a functionally gradedmicrostructure. It is interesting to note that, ifone compares the microstructure of the shellsample to that of the corresponding location inthe cubic sample, it is shown that the former iscoarser than the latter (Figure 5). This differenceis attributed to the higher thermal conductivity ofthe bulk metal (cubic sample) as compared to theheat dissipated via convection into the environ-ment (shell sample). In the case of a given set ofprocess parameters, the microstructural evolutionduring LENS is primarily influenced by the con-duction of thermal energy through the depositedmaterial into the substrate, which effectivelybehaves as a heat sink. Convective and radiativelosses into the environment appear to have only alimited effect on the microstructural evolution. Anadditional factor that contributes to the observeddifference in microstructure between the shelland cubic samples is the fact that the time inter-val between two sequential layers is shorter for


Figure 5. SEM (BSE) micrographs of laser-deposited Fe-based MG cube


the shell sample than for the cubic sample.According to the experimental and numerical sim-ulation results,(24,25,33) the temperature at theend of each deposition cycle increases with adecreasing interval time, which corresponds to adecrease in the cooling rate during deposition. Inaddition, the accumulation of thermal energy thatis likely to develop during the deposition of multi-ple layers is also likely to promote crystallizationof the microstructure.

The energy-dispersive analysis line-scanningresults (Figure 7) show that the precipitated whitephase contained a higher concentration of Cr, W,and Mo relative to the matrix. During the initialstages of phase precipitation, the boundarybetween the precipitated phases and the matrix isnot well denned as the component atoms begin tosegregate and cluster. The phase morphology ofthe precipitated phases becomes as well definedas in the upper regions of the samples, becauseextensive precipitation has been facilitated by a

low cooling rate.Figure 8 shows the XRD patterns obtained from

the top surface of laser-deposited Fe-based MGcoatings with different numbers of deposited lay-ers. The XRD curve of the deposited first layerpresents a diffuse broad halo peak at around 2θ =44.4 deg, illustrating the amorphous nature of thespecimen. The broad diffraction peak becomesless obvious with increasing numbers of depositedlayers. The crystalline peaks appeared superim-posed on a broad diffraction peak for all the coat-ing samples, which is similar to the patternobtained from the gas-atomized powder. Eventhough the SEM BSE images of the first-layersample revealed a featureless microstructurewithin a molten pool region, some crystallinepeaks still appeared on the corresponding XRDcurve. In fact, these peaks were attributed to theprecipitated crystalline in the HAZ and partiallymelted powder, which retained the original par-tially amorphous structure. Three broad peaks at


Figure 6. SEM (BSE) micrographs of laser-deposited MG shell component


around 44.4, 64.5, and 81.7 deg, correspondingto the reflections of the nanocrystalline α-Fephase, can be observed together with a halo peak,which confirms the presence of precipitatednanocrystalline α-Fe embedded in an amorphousmatrix. The other phases presented are likely tobe γ-Fe, tetragonal Fe2B, cubic Cr23C6, and other,unidentified phases.

The microstructure of laser-deposited MG sam-ples was also observed using TEM. Although theinitial deposited layers appear featureless duringobservation with SEM, as shown in Figures 3, 5,and 6, some nanocrystallites of a-Fe with a size of5 to 20 nm, embedded in an amorphous matrix,were observed via TEM. This is illustrated inFigure 9(a), in which the bright-field image and itscorresponding diffraction pattern reveal the pres-

ence of α-Fe diffraction rings. The increased depo-sition thickness resulted in additional precipita-tion, as illustrated in Figure 9(b).

The TEM results also confirmed the observationof an increased degree of crystallinity with theincreased deposition thickness. This phenomenonis illustrated in Figure 9(b), which shows a bright-field image and its corresponding diffraction pat-tern from an upper layer.

The size of the precipitated crystals that are evi-dent in this figure is approximately 100 nm. In allof these cases, a primary crystallization reactionoccurs and starts with the formation of nanocrys-talline α-Fe grains. Further growth of these parti-cles and the appearance of new grains ensued asadditional layers were deposited.

Figure 10 shows the DSC trace curve of thefirst layer of the laser-deposited Fe-based MGcoating, as determined with a heating rate of20°C/min. With increasing temperature, thecurve shows an amorphous transition, followed bythe appearance of a supercooled liquid region andcrystallization. The glass transition temperatureTg corresponds to the temperature at which thecurvature of the endothermic reaction on the DSCcurve is maximum, while the crystallization onsettemperature Tx is defined as the temperature atwhich the tangential lines between the super-cooled liquid and the exothermic peak intersecteach other. The temperature interval of the super-cooled liquid region ∆Tx, defined by the difference


Figure 7. Element distribution around white phase with EDX line scanning

Figure 8. XRD patterns of laser-deposited Fe-based MG coatings with differentnumbers of layers



between the glass transition temperature and theonset temperature of crystallization, ∆Tx = Tx – Tg,is as large as 110°C. In addition, the Tg/Tm valueis 0.37. The large supercooled liquid regionimplies a high thermal stability of the supercooledliquid against crystallization. Generally, the GFAincreases with increasing ∆Tx and Tg/Tm.(3, 37)

Mechanical PropertiesThe microhardness of the LENS-deposited Fe-

based Fe-Cr-Mo-W-C-Mn-Si-Zr-B MG componentwas measured using a 100-g load with a Vickersmicrohardness tester; the results are summarizedin Figure 11. The results show the variation inmicrohardness at the center of the cubic sampleas a function of distance from the substrate sur-face in the height buildup direction. The varia-

tions in microhardness of the cubic MG sample inthe transverse direction, as well as in the centerof a shell sample, as a function of the distancefrom the substrate surface were also measured.No significant variations in microhardness wereobserved in the cases of the transverse measure-ments for the cubic sample and the center meas-urements for the shell sample, despite obviousdifferences in the degree of devitrification. Thevariation in microhardness values obtained fromthe bottom region is significantly smaller thanthat of the upper region, as a result of the pre-dominantly amorphous structure present nearthe bottom region.

The variations in microhardness summarized in

Figure 9. TEM micrograph and its diffraction pattern of (a) first layer of laser-deposited Fe-based MG and (b) coarse microstructure of laser-deposited Fe-based MG

(a)

(b)

Figure 10. DSC curve of the first layer of laser-deposited Fe-based MG

Figure 11. Variation in microhardness at the center of the bulk sample with distance from substrate (Z direction) and laser power exposure



Figure 11 can be attributed to the extent of pre-cipitation throughout the deposited material. It isalso interesting to note that the microhardness ofthe deposited materials was slightly higher for thehigher laser travel speed, which corresponds to adecrease in the interaction time of the laser mate-rials and the associated high cooling rate duringdeposition. The microhardness of laser-depositedFe-based MG materials is approximately 900 HV(9.5 GPa), with a corresponding tensile strength(~1/3 hardness) of approximately 3.1 GPa, whichis significantly higher than the values for conven-tional steels, e.g., 276 to 1882 MPa for carbonsteels, 758 to 1882 MPa for alloy steels, 515 to827 MPa for stainless steels, and 640 to 2000MPa for tool steels.(38) The variation in the aver-age microhardness of the LENS-deposited bulkMG samples with laser exposure is also shown inthe inset of Figure 11. It was found that the aver-age microhardness decreases almost linearly withincreasing laser exposure (laser power/laser trav-el speed), which corresponds to a decreasing cool-ing rate during deposition. The relationshipbetween the average microhardness MH and thelaser exposure P/v was derived by curve fitting,and is given as

MH = 846.7 – 0.23 (P/v) [3]

where P is the laser output power and v is thelaser travel speed.

DISCUSSIONThe microstructure evolution of laser-deposited

Fe-based Fe-Cr-Mo-W-C-Mn-Si-Zr-B MG materi-als during LENS processing is complex, because itnot only depends on the thermal history but it isalso a function of the alloy system. Due to thelayer-additive nature of the LENS process, thethermal behavior associated with the LENSprocess involves numerous reheating cycles.Thus, the assessment of the microstructure evo-lution necessitates an understanding of theresponse of the alloy to these cycles. As shown inprevious numerical and experimental stud-ies,(25,32,33) the thermal behavior associated withthe LENS process involves a series of wave-shaped thermal cycles. Each peak represents alaser heating event as the laser beam passes overa layer and effectively reheats layers that weredeposited previously. The thermal excursionsdampen out when the laser energy source moves

away during the deposition of subsequent layers.After reaching an initial peak temperature, theheat is quickly conducted away for the first layer,which experiences rapid heating and cooling, non-equilibrium conditions. Because of rapid heat lossthrough the substrate during initial deposition,this initial thermal transient results in a highcooling rate (103 to 104 K/s(33,35)) during solidifi-cation and can produce a glassy microstructurein the case of glass-forming alloys, as shown inFigures 3 and 9(a). However, each subsequentpass reheats the previously deposited layers suchthat after several layers are deposited, the initialdeposited layers continue to experience thermalexcursions. When the reheating temperature ishigher than the crystallization onset temperatureTx, new phases will precipitate, implying MGdevitrification. However, the time it takes adeposited upper layer to reheat a lower layer to atemperature above Tx is very short (<0.05 s) foreach deposition sequence, and the thermal energyis rapidly dissipated into the lower layers. Ourmicrostructural analysis shows that a heatingtime as short as this was not sufficient to fullycrystallize the lower layers.

The accumulation of thermal energy duringcomponent fabrication is likely to promote devitri-fication. The accumulation of thermal energy atthe end of each cycle causes the temperature tobe somewhat higher than that at the end of theprevious cycle. Accordingly, the temperatureincreases monotonically with the increasingdeposited material thickness, as confirmed vianumerical and experimental results.(24,33) It thenfollows that the cooling rate decreases with thedeposition thickness, consistent with the observa-tion that the microstructure coarsens from thebottom to the top layers, as illustrated in Figures5, 6, and 9(b). Only when the deposited sampleattains a sufficient thickness will the temperatureof a lower layer exceed Tx and complete crystal-lization occur. From our modeling results,(33) thestable temperature for a 25.4-mm distance fromthe substrate can reach 400°C, when the overalldeposited material is approximately 50.8 mm.This complex thermal cycling will influence notonly the microstructure but also residual stressesas the material is tempered or aged.

There are two key parameters of the LENSprocess, laser output power and travel speed, thatdirectly determine the local thermal conditions(temperature and cooling rate) and therefore con-


trol the resulting microstructure of depositedMGs. These two parameters can be combined intothe energy intensity of a laser beam, which can bedetermined by dividing the power of the beam bythe spot area:

pI = —— [4]

vd

where P is laser output power, v is laser travelspeed, and d is the laser beam spot size in diame-ter on the substrate. For a given laser power,increasing the laser spot size and scanning speedwill decrease the intensity, while a high laserpower will increase the intensity. This thermalenergy input melts the injected powder and thesurface layer of the substrate; it also heats theunderlying material. Both the depth of the meltzone and the thickness of the HAZ increase withincreasing heat input. A fast laser-scanning speedleads to a short interaction time between the laserbeam and the material, which can also promotehigh quenching and lead to the higher strength ofthe deposited Fe-based MGs, as shown in Figure11. The process parameters of laser output power,travel speed, and initial temperature of the sub-strate have significant influences on the thermalhistory of the deposited materials; the coolingprocess can be controlled by changing these vari-ables. The present results suggest that a combi-nation of a laser power of 150 W and a travelspeed of 12.7 mm/s with a powder feed rate of 10g/min appears to be close to ideal for forming amelt pool necessary for powder incorporationwithout causing much crystallization in the initialdeposition.

The behavior of MGs synthesized via LENSlaser deposition depends on both the processparameters and the alloy composition. The Fe-based Fe-Cr-Mo-W-C-Mn-Si-Zr-B alloy used inthe present article has a limited GFA, as is evi-denced by the microstructure of both the gas-atomized and LENS-deposited samples (Figures 2and 3 and 4 through 8). The basis of the presentalloy is the Fe-Mn-Cr-B system,(2,9–11) which sat-isfies the three empirical rules.(12,13) The additionof Mo, W, Zr, C, and Si can cause an increase inthe atomic size difference and the generation ofnew atomic pairs with various negative heats ofmixing. For a multicomponent MG consisting of nconstituent elements, the criterion of the ratio ofthe atomic size difference λn has been used to

evaluate the optimum solute concentration forhigh a GFA;(39) λn is defined as

n–1 rB3

λn = Σ (——) –1 ·CB [5]B=1

rA

where rA and rB are the solvent and solute atomradius, respectively, and CB is the solute concen-tration (at. pct) of element B. It is found that thevalues of λn of bulk MG formers with a great GFAin Zr-, Pd-, Mg-, Nd- and Fe-based systems areapproximately constant of 0.18. The λn is 0.21 forthe composition corresponding to theFe58Cr15Mn2B16C4Mo2Si1W1Zr1 (at. pct) alloy. Thelarge atomic size difference in the multicompo-nent system can result in the highly dense andrandomly packed structure of MG alloys. Thenucleation and growth of the crystalline phasemay be suppressed in the supercooled liquid byinhibiting the long-distance diffusion and increas-ing the melt viscosity. It is also very difficult forthe multiple elements in the alloy to simultane-ously satisfy the composition and structuralrequirements of the crystalline compounds. Minoralloying additions are frequently added to MGs, toimprove GFA and effectively "tune" the mechani-cal and physical properties of bulk MGs.(40) Theaddition of metalloid elements such as B, C, andSi has a significant effect on the GFA, thermalstability, and properties of Fe-based MG-formingalloys. Proper additions of small atomic-sized ele-ments such as B, C, and Si can tighten the alloystructure and stabilize the alloy against crystal-lization. Minor additions of Zr enable this alloy tobehave as a liquidlike structure at low tempera-tures and to remain amorphous as it solidifies,due to the strong affinity Zr has for O. However,the as-received alloy used in the present investi-gation shows a limited GFA. Recently, Fe-basedalloys with a high GFA have been developed (e.g.,Fe-Cr-Mo-Y-C-B) and should be of interest forLENS studies, because results show that a fullyamorphous structure in the gas-atomized powdersize range 40 to 150 µm were obtained.(41)

The observed Fe-based Fe-Cr-Mo-W-C-Mn-Si-Zr-B amorphous phase in the laser-deposited samplescan be attributed to the rapid solidification thatoccurs during rapid cooling as the thermal energyis transferred into the substrate. In this case, thenucleation and growth of crystallites are hinderedby the local rapid drop in temperature. Beyond the



initial layers, however, the temperature of thedeposited material constantly increases as addi-tional layers are added, which results in a decreasein the cooling rate and, hence devitrification, asshown in Figures 5 and 6. According to the experi-mental and modeling results,(25,33) the temperaturecould increase to a value of approximately 150°C atthe end of the second-layer deposition, and thecooling rate would decrease to approximately 10-2

K/s for the third-layer deposition. This indicatesthat a constant cooling rate of at least >10-2 K/s isrequired for depositing this type of Fe-based MGsvia the LENS process, based on the absence ofcrystallization.

The inherent variation in the cooling rate dur-ing LENS processing can lead to the formation ofgraded materials with an in-situ-formed MGmatrix composite, as shown in Figures 5 and 6. Itis interesting to note that this type of microstruc-ture has been reported to be beneficial forstrength and fracture toughness.(7,42) In thesemicrostructures, fracture may be suppressed bylimiting strain localization by the precipitatedreinforcing phase. The precipitated phases canalso help distribute both shear bands and microc-racks, limit shear band extension, suppress shearband opening, and avoid crack development.

These preliminary research results on LENS-deposited MG components indicate their flexibilityin processing novel materials, even those in whichthe thermal and solidification conditions mustmeet certain conditions. The cracks that were evi-dent in the deposited MGs, as shown in shellsample C in Figure 1, are attributable to the lackof ductility of MGs and to residual stress develop-ment, which is an intrinsic outcome of incremen-tal deposition processes such as LENS.(43)

SUMMARYThe microstructure of the gas-atomized Fe-

based alloy Fe-Cr-Mo-W-C-Mn-Si-Zr-B powderused in the present work was not fully amor-phous. During the initial stages of deposition withLENS processing, significant rapid quenchingoccurs and two Fe-based predominantly amor-phous layers are created. With an increasingdeposit thickness, new crystal phases precipitatedand the microstructure coarsens due to the impo-sition of reheating cycles in combination with adecreasing cooling rate. The number of α-Fe parti-cles and other precipitated phases increases withthe increasing number of deposited layers, forming

graded composites with in-situ-precipitated parti-cles in an MG matrix. The microhardness of thedeposited Fe-based Fe-Cr-Mo-W-C-Mn-Si-Zr-BMGs is approximately 900 HV (9.52 GPa), a valuethat is attractive for engineering applications.

ACKNOWLEDGMENTSThis work was sponsored by the National

Science Foundation (NSF DMR00-76498). Theauthors thank Professor Julie M. Schoenung ofthe University of California, Davis, for construc-tive technical discussions on LENS processing.

OPEN ACCESSThis article is distributed under the terms of

the Creative Commons Attribution Non-commercial License which permits any noncom-mercial use, distribution, and reproduction in anymedium, provided the original author(s) andsource are credited.

REFERENCES1. A. Peker and W.L. Johnson: Appl. Phys. Lett., 1993, vol.

63, pp. 2,342–44.2. A. Inoue: Mater. Trans. JIM, 1995, vol. 36, pp. 866–75.3. W.L. Johnson: MRS Bull., 1999, vol. 24, pp. 42–56.4. W.H. Wang, Z.X. Bao, C.X. Liu, and D.Q. Zhao: Phys. Rev.

B, 2000. vol. 61, pp. 3,166–69.5. Y.H. Liu, G. Wang, R.J. Wang, D.Q. Zhao, M.X. Pan, and

W.H. Wang: Science, 2007, vol. 315, pp. 1,385–88.6. J. Zhang and Y. Zhao: Nature, 2004, vol. 430, pp. 332–35.7. D.C. Hofmann, J.-Y. Suh, A. Wiest, G. Duan, M.-L. Lind,

M.D. Demetriou, and W.L. Johnson: Nature, 2008, vol.451, pp. 1,085–89.

8. Z.P. Lu, C.T. Liu, J.R. Thompson, and W.D. Porter: Phvs.Rev. Lett., 2004, vol. 92, pp. 245,503–245,511.

9. C.T. Liu, M.F. Chisholm, and M.L. Miller: Imermetallics,2002, vol. 10, pp. 1,105–12.

10. Z.P. Lu and C.T. Liu: Phys. Rev. Lett., 2003, vol. 91, pp.115,505–115,511.

11. A. Inouc, T. Masumoto, S. Arakawa, and T. Iwadachi:Mater. Trans., JIM, 1978, vol. 19, pp. 303–04.

12. A. Inoue, T. Zhang, and T. Masumoto: Mater. Trans., JIM,1989, vol. 30, pp. 965–72.

13. A. Inoue, T. Zhang, and T. Masumoto: J. Non-Crvst. Solids,1993, vols. 156-158, pp. 473–80.

14. H. Habazaki, A. Kawashima, K. Asami, and K. Hashimoto:J. Electrochem. Soc., 1991, vol. 138, pp. 76–81.

15. K. Kobayashi, K. Hashimoto, and T. Masumoto: Res. Inst.Tohoku Univ., A, 1981, vol. 29, pp. 284–95.

16. H. Habazaki, A. Kawashima, K. Asami, and K. Hashimoto:Corros. Sci., 1992, vol. 33, pp. 225–36.

17. T.R. Anthony and H.E. Cline: J. Appl. Phvs., 1978, vol. 49,pp. 1,248–55.

18. Y.-W. Kirn, P.R. Strutt, and H. Nowotny: Metal/. Trans. A,1979, vol. 10A, pp. 881–86.

19. Q. Zhu, S. Qu, X. Wang, and Z. Zou: Appl. Surf. Sci.,2007, vol. 253, pp. 7,060–64.



20. T.T. Wong and G.Y. Liang: Mater. Characl., 1997, vol. 38,pp. 85–89.

21. X. Wu, B. Xu, and Y. Hong: Mater. Lett., 2002, vol. 56, pp.838–41.

22. T.M. Yuc, Y.P. Su, and H.O. Yang: Mater. Lett., 2007, vol.61. pp. 209–12.

23. C.L. Atwood, M.L. Griffith, L.D. Harwell, D.L. Greene, D.E.Reckaway, M.T. Ensz, D.M. Keicher, M.E. Schlienger, J.A.Romero, M.S. Oliver, P.P. Jcantette, and J.E. Smugcrcsky:Sandia Report No. SAND99-0739, Sandia NationalLaboratories, Albuquerque, NM, 1999, pp. 1–31.

24. B. Zheng, Y. Lin, J.E. Smugeresky, Y. Zhou, and E.J.Lavernia: TMS Lett., 2005, vol. 4, pp. 113–14.

25. M.L. Griffith, M.E. Schlienger, L.D. Harwell, M.S. Oliver,M.D. Baldwin, M.T. Ensz, M. Essien, J. Brooks, C.V.Robino, J.E. Smugeresky, W.H. Hofmeister, M.J. Wert,and D.V. Nelson: Mater. Des., 1999, vol. 20, pp. 107–13

26. E.J. Lavernia and Y. Wu: Spray Atomization andDeposition, John Wiley & Sons, Inc., West Sussex, UnitedKingdom, 1996, pp. 70–77.

27. S. Annavarapu and R. Doherty: Int. J. Powder Metall.,1993, vol. 29, pp. 331–44.

28. K.R. Cardoso, A.G. Escorial, M. Lieblich, and W.J. Botta:Mater. Sci. Eng.. A, 2001, vol. 315, pp. 89–97.

29. A. Zambon, B. Badan, G. Vcdovato, and E. Ramous:Mater. Sci. Eng., A, 2001, vols. 304-306, pp. 452–56.

30. Y. Liu, Z. Liu, S. Guo, Y. Du, B. Huang, J. Huang, S. Chen,and F. Liu: Intermetallics, 2005, vol. 13, pp. 393–98.

31. J.F. Ready and D.F. Farson: LIA Handbook of LaserMaterials Processing: Laser Institute America, MagnoliaPublishing, Orlan-do, FL, 2001, pp. 181–82.

32. R. Ye, J.E. Sraugeresky, B. Zheng, Y. Zhou, and E.J.Lavernia: Mater. Sci. Eng., A, 2006, vol. 428, pp. 47–53.

33. B. Zhcng, Y. Zhou, J.E. Smugeresky, J.M. Schocnung,and E.J. Lavcrnia: Metall. Mater. Trans. A, 2008, vol. 39A,pp. 2,228–36.

34. A. Basu, A.N. Samant, S.P. Harimkar, J.D. Majumdar, I.Manna, and N.B. Dahotre: Surf. Coat. Technol, 2008, vol.202, pp. 2,623–31.

35. W. Hofmeister, M. Wert, J.E. Smugeresky, J.A. Philliber,M. Grif fith, and M. Ensz: JOM-e, available onlineat:http://www. tms.org/pubs/journals/JOM/9907/Hofmeister/Hofmeister-9907. html, 1999, vol. 51.

36. B. Zheng, L. Ajdelsztajn, J.M. Schoenung, and E.J.Lavernia: 4th ISEC, St. Paul, MN, 2005, p. 9.

37. T. Egami: Mater. Trans., JIM, 2002, vol. 43, pp. 510–17.38. eFunda: http://www.efunda.com/materials/alloys/

alloy_home/steels_ properties.cfm.39. Z.J. Yan, J.F. Li, S.R. He, and Y.H. Zhou: Mater. Res. Bull.,

2003, vol. 38, pp. 681–89.40. W.H. Wang: Prog. Mater. Sci., 2007, vol. 52, pp. 540–52.41. B. Zheng: Ph.D. Dissertation, University of California,

Davis, CA, 2006, pp. 242–43.42. M.L. Lcc, Y. Li, and C.A. Schuh: Ada Mater., 2004, vol. 52,

pp. 4.121–31.43. J. Beuth and N. Klingbeil: JOM, 2001, vol. 53, pp. 36–39.


ijpm


INTRODUCTIONThe heating of iron-and-aluminum powder mixes is accompanied by

heat generation, due to the exothermic nature of the material.Initiation of an exothermic reaction in the compacted iron-and-alu-minum powder mix is termed self-propagating high-temperature syn-thesis (SHS), or combustion synthesis.1–5 In combustion-synthesisreactions, the mix of reactant powders is compacted and subsequentlyignited, either locally or by heating the entire compact to the ignitiontemperature of the exothermic reaction.

Compared with conventional sintering, the primary advantages ofSHS are:

• A short exothermic reaction time• The generation of a high reaction temperature that can volatilize

low boiling-point impurities and result in enhanced purity • A high thermal gradient and rapid cooling that can give rise to new

nonequilibrium or metastable phases• The opportunity for simultaneous synthesis and densificationThe main disadvantage of SHS is the relatively high level of porosity

in the final product, resulting in densities that can exceed 50% of thepore-free level.1–4,6 To reduce or eliminate porosity, the use of elemen-tal iron-and-aluminum powder mixes with prealloyed intermetallicpowders has been proposed.1 Others have described the application ofpressure during combustion or sintering, which adds to the complexityof the overall process.2–4,7–10

Joslin et al.3,4 analyzed the fabrication of iron–aluminum alloys anddetermined that several factors affect the progress and timing of theattendant synthesis reactions. Powder-particle size, reaction atmos-phere, heating rate, and composition all play a role. Ultimately, these

The influence of chemicalcomposition on the intensityof the self-propagating high-temperature synthesis (SHS)reaction accompanying thesintering of iron-and-aluminum powder mixeshas been evaluated.Processing parameters werecorrelated with the reactionenthalpy and starting temperature of the SHSreaction. Differential scanning calorimetry (DSC)reveals that the SHS reaction enthalpy undergoesmonotonic changes over thealuminum range studied.The maximum enthalpy isattained in stoichiometricFeAl at the lowest SHS ignition temperature.

EXOTHERMICREACTIONS DURING THE SINTERING OFELEMENTAL IRON-AND-ALUMINUM POWDERMIXESStanislaw Józwiak*, Krzysztof Karczewski**, and Zbigniew Bojar***

RESEARCH &DEVELOPMENT

*Assistant Professor, **Post Doc., ***Professor, Department of Advanced Materials and Technology, Faculty of Advanced Technology andChemistry, Military University of Technology, Kaliskiego 2, 00-908 Warsaw, Poland; E-mail address: [email protected]

EXOTHERMIC REACTIONS DURING THE SINTERING OF ELEMENTAL IRON-AND-ALUMINUM POWDER MIXES


factors affect heat generation and accumulation,the processes that govern the outcome of thereaction.

In our previous work,11,12 a 50 mm dia., 100 gcylindrical compact was sintered under a load of50 kN. The load measurement was carried outunder compression in an Instron Model #8802.Figure 1 shows that there is a significant changein the loading curve during the SHS reaction. Thisis indicative of the generation of high reactionenergy and is believed to be the source of porosityin the sintered compact. The work presented herewas undertaken to elucidate details of the reac-tions in the iron–aluminum binary system.

EXPERIMENTAL PROCEDUREElemental powders of iron (99.8 w/o) with an

average particle size of 200 µm and aluminum(99.6 w/o) with an average particle size of 70 µmwere combined to give the following compositions:Fe-40 a/o Al (24.4 w/o Al), Fe-45 a/o Al (28.3 w/oAl) and Fe-50 a/o Al (32.6 w/o Al). The powderswere mixed utilizing ball milling and were subse-quently cold compacted uniaxially.

Compacts were fabricated at a pressure of1,000 MPa and cut into standard cylindrical DSCspecimens (2 mm dia. and 70 mg weight) by sparkmachining. Thermal analysis was performed uti-lizing a DSC/thermogravimetric (TGA) instrumentwith a heating rate of 10°C/min from room tem-perature to 750°C in flowing argon (16 ml/min).The heating rate of 10°C/min was the same asthat used during sintering in our previouswork.11,12 DSC was used to determine the start-ing temperature of the SHS reaction and thechange in heat evolution during the SHS reaction.

Microstructural evaluation and chemical analy-

ses in sintered areas were carried out utilizing aPhilips XL30 (LaB6) scanning electron microscope(SEM) integrated with X-ray energy dispersivemicroanalysis (EDAX). X-ray diffraction (XRD)phase analysis was performed on a 3003TTSeifert diffractometer with access to a PDF-2database. Cu K∝ 1 radiation (λ = 0.15405 nm), atan accelerating voltage of 40 kV and a current of40 mA, was used in this study. The scan rangewas from 2θ = 20 to 120° with a scan time of 3 sand a step size of 0.02°.

Microindentation hardness measurements werecarried out at room temperature using aShimadzu Vickers tester with a 100 g load and 5 sdwell time.

RESULTS AND DISCUSSIONDSC traces for the Fe-40 a/o Al, Fe-45 a/o Al,

and Fe-50 a/o Al powder mixes are shown inFigure 2. The corresponding DSC reaction param-eters are cited in Table I.

Figure 3 shows changes in the microindenta-tion hardness of the iron-and-aluminum con-stituent powders after heating the compact at arate of 10°C/min. Cold work, as a result of defor-mation of the compact under 1,000 MPa pressure,caused an increase in the microindentation hard-ness of the aluminum powder from 26HV0.1 to

Figure 1. Change in load during SHS reaction in Fe 50 a/o Al

Figure 2. Calorimetric curves of iron–aluminum mixes (heating rate10°C /min)



52HV0.1 and of the iron powder from 52HV0.1 to123HV0.1. Supplying thermal energy to the com-pact resulted in a decrease in the microindenta-tion hardness of the aluminum at 250°C and ofthe iron at 400°C, due to recovery and recrystal-lization.

Microindentation hardness increases afterheating at temperatures >500°C for the aluminumpowder and 550°C for the iron powder; however, itdoes not reach the same hardness as that ofdeformed iron and aluminum powders. Figure 4illustrates the microstructure of a compact after

heating to 600°C. No changes are visible in thecompact compared with the microstructure of thepressed samples. Etch pits in the iron powderparticles are the result of polygonization.

Figure 5 is a representative microstructure of acompact subjected to interrupted sintering at610°C. At some contact points of the iron and alu-minum particles, precipitates of Fe2Al5 are visible.Based on the binary Fe-Al equilibrium diagram,and in conformity with Fick’s laws of diffusion,the formation of FeAl3 should precede the forma-tion of Fe2Al5; however, FeAl3 was not observed.

TABLE I. DSC REACTION PARAMETERS*

Aluminum Measurement Onset of Peak #1 Maximum of Onset of Peak #2 Maximum of Offset Total Enthalpy Enthalpy of Enthalpy ofContent Number (°C) Peak #1 (°C) (°C) Peak #2 (°C) (°C) (mW*s/mg) Peak #1 Peak #2

(a/o) (mW*s/mg) (mW*s/mg)

1 601.0 617.2 639.2 642.1 645.8 350.8 118.6 232.32 607.4 622.4 638.8 642.0 644.3 364.2 85.5 278.7

40 3 603.9 620.1 637.7 641.1 644.2 273.8 76.5 197.0Average 604.1 619.9 638.6 641.7 644.8 329.6 93.5 236.0

SD 3.2 2.6 0.8 0.6 0.9 48.8 22.2 41.0

1 589.2 612.4 627.6 631.1 632.4 436.1 120.3 315.72 590.5 619.4 625.7 629.2 631.0 407.7 137.3 270.4

45 3 591.2 616.2 627.4 630.8 632.6 443.6 113.9 329.7Average 590.3 616.0 626.9 630.4 632.0 429.1 123.8 305.3

SD 1.0 3.5 1.1 1.0 0.9 18.9 12.1 31.0

1 586.7 609.8 622.0 625.2 627.1 440.1 142.7 297.42 582.4 615.9 622.5 626.2 629.1 510.6 177.3 396.8

50 3 582.6 604.8 624.7 628.8 630.0 497.0 176.5 320.5Average 583.9 610.1 623.1 626.7 628.7 482.6 165.5 338.3

SD 2.4 5.6 1.5 1.8 1.5 37.4 19.7 52.0

*Refer to Figure 2

Figure 3. Microindentation hardness of Fe-50 a/o Al powder mix after heating ata rate of 10°C/min.

Figure 4. Representative microstructure of Fe-50 a/o Al compact after heating to600°C temperature



The strain hardening of iron and aluminumafter heating above 400°C suggests that theincrease in microindentation hardness can beattributed to the precipitation of intermetallicswith a high aluminum content and which have alarger lattice parameter than does iron and alu-minum. The formation of FeAl3 precipitates andthe transformation in Fe2Al5 is reflected in theheat generation observed in the DSC curves(Figures 2 and 3).

The exothermic processes involving the forma-tion of FeAl3 and Fe2Al5 precede the SHS reaction(Figures 2 and 3) and influence the changes in thethermodynamic parameters cited in Table I dur-ing sintering of the compact. The release of inter-nal energy resulting from the formation of FeAl3and Fe2Al5 is considered to be a fundamental fac-tor in influencing the starting temperature of theSHS reaction. A higher aluminum content in thestarting powder mix decreases the temperature offormation of the two intermetallics (Figure 6), anddecreases the SHS start temperature (Figure 7).The increase in the formation enthalpy of FeAl3and Fe2Al5 (Figure 8) is reflected in an increase inthe total energy of the compact; this allows theSHS reaction to initiate with lower external ener-gy, i.e., at the lower heating temperature of thecompact (Figure 7). According to theGibbs–Duhem equation,13 the increase in alu-minum content is responsible for the increase inenergy released during the SHS reaction, Figure9. This assumes that the enthalpy generated dur-ing the SHS reaction of the intermetallics remainsapproximately constant.

The thermodynamic parameters show monoto-

nic changes during diffusion preceding the SHSreaction, and are dependent on the aluminumcontent (Figures 6, 7, 8, and 9).

The results of the XRD phase analysis areshown in Figure 10. These show that iron, FeAl3,Fe2Al3, and FeAl are present after the SHS reac-tion. A quantitative determination of the propor-tions of each constituent was not made.

SUMMARY AND CONCLUSIONSA DSC investigation of iron-and-aluminum

powder mixes reveals that the reaction enthalpyundergoes monotonic changes over the aluminumrange evaluated. The maximum enthalpy isattained in the stoichiometric composition FeAl.The analysis confirms the complexity of the Fe-Alintermetallic formation, which influences the pri-

Figure 5. Microstructure of Fe-50 a/o Al compact after heating to 610°C Figure 6. Influence of aluminum content on reaction temperature for formation ofFeAl3 and Fe2Al5

Figure 7. Influence of aluminum content on SHS ignition temperature



mary SHS reaction parameters. Precipitation atthe contact points of the iron and aluminum pow-der particles, observed prior to the SHS reaction,is an example of this complexity.

REFERENCES1. S. Gedevanishvili and S.C. Deevi, “Processing of Iron

Aluminides by Pressureless Sintering Through Fe + AlElemental Route”, Materials Science and Engineering,2002, vol. 325, no. 1–2, pp. 163–176.

2. J.L. Jordan and S.C. Deevi, “Vacancy Formation andEffects in FeAl”, Intermetallics, 2003, vol. 11, no. 6, pp.507–528.

3. D.L. Joslin, D.S. Easton, C.T. Liu, S.S. Babu and S.A.David, “Processing of Fe3Al and FeAl Alloys by ReactionSynthesis”, Intermetallics, 1995, vol. 3, no. 6, pp.467–481.

4. D.L. Joslin, D.S. Easton, C.T. Liu and S.A. David,“Reaction Synthesis of Fe-Al Alloys”, Materials Science andEngineering, 1995, vol. 192–193, part 2, pp. 544–548.

5. Z. Bojar, T. Durejko, S. Józwiak, T. Czujko and R.A. Varin,”Microstructure and Wear Resistance of SinteredIntermetallics in Fe-Al System”, 25th Canadian MetalChemistry Conference, Sudbury, 2001.

6. K. Karczewski, S. Jó zwiak, Z. Bojar and T. Durejko,”Material/y na Oosnowie faz Mmiedzymetalicznych z Ukl/aduFe–Al z Udzial/em Al2O3”, Archiwum Odlewnictwa, 2003,vol. 3, no. 7, pp. 301–312.

7. T. Durejko, Z. Bojar and S. Józwiak, “Structure andProperties of FeAl Sinters Resistant to Abrasive Wear”,International Journal of Applied Mechanics andEngineering, 2002, vol. 7, Special Issue: SITC 2002, pp.347–350.

8. J. Bystrzycki, R.A. Varin and Z. Bojar, ”Postepy wBadaniach Stopów na Bazie Uporzadkowanych fazMiedzymetalicznych z Udzial/em Aluminium”, Inz·ynieriaMaterialowa, 1996, vol. 5, pp. 137–145.

9. S. Józwiak, T. Durejko and Z. Bojar, “Structure andProperties of Fe-Al Based Heterogeneous IntermetallicMaterials”, Acta Metallurgica Slovaca, 2002, Special Issue:2/2002 (2/2), pp. 421–426.

10. H. Bakker, G.F. Zhou and H. Yang, “Mechanically DrivenDisorder and Phase Transformation in Alloys”, Progress inMaterials Science, 1995, vol. 39, no. 3, pp. 159–241.

11. S. Józwiak, K. Karczewski and Z. Bojar, “The Changes ofSHS Reaction Parameters in Sintering Process of Iron andAluminum Elemental Powders”, SHS 2007 IX InternationalSymposium on Self-Propagating High-TemperatureSynthesis, Faculté des Sciences, Université de Bourgogne,Dijon, France, 2007, T2_P05 p. 2.

12. S. Józwiak, K. Karczewski and Z. Bojar, “SHS Reaction inSintering Process of FeAl-Based Intermetallics”, ibid,T2_P06 p. 2.

13. E. Tyrkiel, Termodynamiczne podstawy material/oznawst-wa, Oficyna Wydawnicza Politechniki Warszawskiej,Warszawa, 2005.

Figure 8. Influence of aluminum content on enthalpy of formation of FeAl3 andFe2Al5

Figure 9. Influence of aluminum content on enthalpy of SHS reaction

Figure 10. Analysis of constituents in Fe-50 a/o Al after SHS reaction

ijpm


2009

SDMA 2009/ICSF VII—4TH INTERNATIONAL CONFERENCEON SPRAY DEPOSITION AND MELT ATOMIZATION/7TH INTERNATIONAL CONFERENCEON SPRAY FORMING

September 7–9Bremen, Germanywww.sdma-conference.de/

EUROMAT 2009EUROPEAN CONGRESS ANDEXHBIITION ON ADVANCEDMATERIALS & PROCESSES

September 7–10Glasgow, UKwww.euromat2009.fems.eu

25TH ASM HEAT TREATINGSOCIETY CONFERENCE ANDEXPOSITION

Co-located with AGMA GearExpo 2009

September 14–17Indianapolis, INwww.asminternational.org/he

attreat

EURO PM2009INTERNATIONAL POWDERMETALLURGY CONGRESS &EXHIBITION

October 12–14Copenhagen, Denmarkwww.epma.com/pm2009

HIGHMATTECH 2009INTERNATIONAL CONFERENCE

October 19–23Kiev, Ukrainewww.hmt.kiev.ua

CERAMITEC 200911TH INTERNATIONAL TRADE FAIRFOR MACHINERY, EQUIPMENT,PLAN, PROCESSES AND RAWMATERIALS FOR CERAMICS ANDPOWDER METALLURGY

October 20–23Munich, Germanywww.ceramitec.de

96TH ASM ANNUAL MEETING ATMS&T 2009

October 25–29Pittsburgh, PAwww.matscitech.org

PM COMPACTING/TOOLINGSEMINAR

October 27–28Cleveland, OHMPIF*

2009 CHINA (SHANGHAI) POWDERMETALLURGY & ADVANCEDCERMAICS EXHIBITION &CONGRESS

November 9–10Shangahi, Chinawww.china-pmexpo.com/en

2010

INTERNATIONAL CONFERENCE &EXHIBITION ON POWDERMETALLURGY PROCESSING OFPARTICULATE MATERIALS ANDPRODUCTS & 36TH ANNUALTECHNICAL MEETING

January 28–30Rajasthan, Indiawww.pmai.in

POWDERMET2010: MPIF/APMI INTERNATIONALCONFERENCE ON POWDERMETALLURGY & PARTICULATEMATERIALS

June 27–30Hollywood (Ft. Lauderdale), FLMPIF*

PRICM 77TH PACIFIC RIM INTERNATIONALCONFERENCE ON ADVANCEDMATERIALS AND PROCESSING

August 1–5Cairns, Australiawww.materialsaustralia.com.

au/scripts/cgiip.exe/WService=MA/ccms.r?PageID=19070

ILASS 201023RD ANNUAL CONFERENCE ONLIQUID ATOMIZATION AND SPRAYSYSTEMS

September 6–8Brno, Czech Republicwww.ilasseurope2010.org

7TH INTERNATIONAL SYMPOSIUMON ALLOY 718 & DERIVATIVES

September 10–13Pittsburgh, PAwww.tms.org

PM2010 WORLD CONGRESS October 10–14Florence, Italy

MEETINGS ANDCONFERENCES

*Metal Powder Industries Federation105 College Road East, Princeton, New Jersey 08540-6692 USA

(609) 452-7700 Fax (609) 987-8523Visit www.mpif.org for updates and registration. Dates and locations may change

http://www.mpif.org/Meetings/Conference.asp?linkid=14#PowMet2010


INSTRUCTIONSFOR AUTHORS

The Journal reports on scientific and technologicaldevelopments worldwide in the powder metallurgy andparticulate materials industries. Articles cover boththe scientific/theoretical and practical aspects of thetechnology. Subjects addressed include: powder pro-duction and characterization; compaction; sintering;consolidation to full density; powder injection mold-ing; consolidation to full density; and hybrid particu-late processes such as spray forming and thermalspraying. The Journal also embraces review articles,PM industry news, company profiles, a consultants’corner, newsmakers, conference reports and bookreviews.

The Journal’s audience includes: powder metallur-gists, engineers, researchers, educators, students,technical managers, and users of powders, PM partsand particulate materials.

Manuscript Requirements1. The primary author should be a member of APMI

International. 2. a. All manuscripts must be typewritten, double

spaced and on one side of the paper only. Authorsshould limit manuscripts to 10 printed pages inthe Journal. For guidance, this is roughly 30 double-spaced pages—including text, references,figures and tables.

b. Authors must submit their manuscript on CD, inMicrosoft Word, and include three printed copiesof the manuscript. All images should be digital, injpg or tif format, and at least 300 dpi at 4x6 inch-es. Please include digital images in separate files,as well as included in the text of the manuscript.

c. Micrographs must include a magnification mark-er in the lower right-hand corner.

d. Tables and figures must include completedescriptive captions.

e. Equations, tables, references and figures shouldbe numbered separately and consecutivelythroughout the text.

f. Papers must be in English, be original and not bepublished elsewhere. Translated papers pub-lished in other languages will be considered pro-vided the author receives permission and sub-mits a copyright release from the publicationinvolved. Particular attention should be given togrammar/syntax; the Journal is not in a positionto assist foreign authors in technical writing.

3. Authors and co-authors must provide completenames, mailing addresses, job titles and affilia-tions, as they wish them to appear in the Journal.A letter accompanying the manuscript shouldgive the name, complete address, telephone num-ber, fax number and e-mail address of the authorto whom correspondence should be sent.

4. Each paper must include an abstract of approxi-mately 100 words that summarizes concisely thepaper’s objectives, methods, results, observa-tions, mode of analysis and conclusions.

5. Système International (SI) units are mandatory. Ifindustrial practice dictates the use of other sys-tems of units, such units must be included inparentheses. As a guide for authors, frequentlyused SI units and the corresponding conversionfactors are provided overleaf.

6. Weight percent, atomic percent and volume percent should be given as w/o, a/o and v/o,respectively.

7. References must be numbered, placed at the endof the paper, and must adhere to the followingformat:JournalT. Le, R. Stefaniuk, H. Henein and J-Y. Huôt,“Measurement and Analysis of Melt Flowrate inGas Atomization”, Int. J. Powder Metall., 1999,vol. 35, no. 1, pp. 51–60.BookR.M. German, Powder Metallurgy Science, SecondEdition, 1994, Metal Powder IndustriesFederation, Princeton, NJ.Article in Book/Conference ProceedingsS.H. Luk, F.Y. Chau and V. Kuzmicz, “HigherGreen Strength and Improved Density byConventional Compaction”, Advances in PowderMetallurgy & Particulate Materials, compiled byJ.J. Oakes and J.H. Reinshagen, Metal PowderIndustries Federation, Princeton, NJ, 1998, vol.3, part 11, pp. 81–99.PatentI.L. Kamel, A. Lawley and M-H. Kim, “Method ofMolding Metal Particles”, U.S. Patent No.5,328,657, July 12, 1994.ThesisD.J. Schaeffler, “High-Strength Low-CarbonPowder Metallurgy Steels: Alloy Development withTransition Metal Additions”, 1991, Ph.D. Thesis,Drexel University, Philadelphia, PA.Technical ReportT.M. Cimino, A.H. Graham and T.F. Murphy, “TheEffect of Microstructure and Pore Morphology onMechanical and Dynamic Properties of FerrousP/M Materials”, 1998, Hoeganaes TechnicalData, Hoeganaes Corporation, Cinnaminson, NJ.Web Site ContentJ.R. Dale, “Connecting Rod Evaluation”, MetalPowder Industries Federation, http://www.mpif.org/design/conrod.pdfPrivate Communication P.W. Taubenblat,1999, Promet Associates, Highland Park, NJ, private communication.

International Journal of Powder MetallurgyInstructions for Authors

INSTRUCTIONS FOR AUTHORS


SYSTÈME INTERNATIONAL UNITS (SI) AND CONVERSION FACTORSAdapted from: R.M. German, Powder Metallurgy Science, Second Edition,

Metal Powder Industries Federation, Princeton, NJ 1994

The author(s) will be sent a copyright form, whichmust be returned before the paper can be published.A reprint order form will also be sent to the author(s).All manuscripts submitted to the Journal should besent to the Editor-in-Chief, who will make an initialdecision on the paper’s suitability for external review.Papers are then subject to review by two members ofthe Editorial Review Committee. Papers are acceptedwith the understanding that they may be returned tothe author(s) for revision, based on the reviewer’s rec-

ommendations. They may also be edited by theJournal’s staff for clarity and conciseness.

Articles should be submitted to:Dr. Alan LawleyEditor-in-ChiefInternational Journal of Powder Metallurgy105 College Road EastPrinceton, NJ 08540-6692 USA

Questions may be e-mailed to: [email protected]

Length Conversions:1 m = 39.4 in. (inch)1 m = 3.28 ft. (foot)1 m = 1.09 yd. (yard)1 cm = 0.394 in. (inch)1 mm = 0.0394 in. (inch)1 µm = 39.4 µin (microinch)1 nm = 10 Å (angstrom)Area and Volume Conversions:1 cm2 = 0.155 in.2 (square inch)1 m2 = 1,550 in.2 (square inch)1 cm3 = 0.061 in.3 (cubic inch)1 m3 = 35 ft.3 (cubic foot)1 L = 1,000 cm3 (cubic centimeter)1 L = 0.264 gal. (gallons)1 L = 1.06 qt. (quart)Amount of Substance Conversion:1 mol = 6.022·1023 moleculesDensity Conversions:1 Mg/m3 = 1 g/cm3

1 g/cm3 = 0.0361 lb./in.3 (pound per cubic inch)1 kg/m3 = 10-3 g/cm3

Temperature Conversion:to convert K to °F (fahrenheit), multiply by 1.8 then

subtract 459.4°Fto convert °C to °F (fahrenheit), multiply by 1.8 then

add 32°FHeating and Cooling Rate Conversions:1 K/s = 1°C/s = 1.8°F/s1 K/min = 1.8°F/minMass Conversions:1 g = 0.035 oz. (ounce)1 kg = 2.2 lb. (pound)1 Mg = 1.1 ton (ton = 2,000 pounds)Force Conversions:1 N = 105 dyne1 N = 0.225 lbf (pound force)Pressure, Stress and Strength Conversions:1 Pa = 0.0075 torr (millimeter of mercury)

1 Pa = 10 dyne/cm2 (dyne per centimeter square)1 kPa = 0.145 psi (pounds per square inch)1 MPa = 9.87 bar (atmosphere)1 MPa = 145 psi (pounds per square inch)1 MPa = 0.145 kpsi (thousand pounds per square inch)1 Gpa = 145 kpsi (thousand pounds per square inch)Energy Conversions:1 J = 9.48 ·10-4 btu (British thermal unit)1 J = 0.737 ft.·lbf (foot pound force)1 J = 0.239 cal (calorie)1 J = 107 erg1 J = 2.8 ·10-7 kw ·h (kilowatt hour)1 J = 6.24·1018 eV (electron volt)1 J = 4.83 hp·h (horsepower·hour)1 J = 1 W·s (watt second)1 J = 1 V·C (volt coulomb)1 kJ = 0.239 kcal (kilocalorie)Power Conversions:1 W = 0.737 ft.·lb./s (foot pound per second)1 W = 1.34 ·10-3 hp (horsepower)Thermal Conversions:1 J/(kg·K) = 2.39 ·10-4 btu/(lb .·°F) (British thermal unit

per pound per degree fahrenheit)1 J/(kg·K) = 2.39 ·10-4 cal/(g ·°C) (calorie per gram per

degree celsius)1 W/(m·K) = 0.578 btu/(ft.·h·°F) (British thermal unit

per foot per hour per degree fahrenheit)1 W/(m·K) = 2.39 ·10-3 cal/(cm·s ·°C) (calorie per

centimeter per second per degree celsius)Viscosity Conversions:1 Pa·s = 1 kg/(m·s)1 Pa·s = 10 P (poise)1 Pa·s = 103 cP (centipoise)Stress Intensity Conversion:1 MPa·m1/2 = 0.91 kpsi·in.1/2 (kilopounds per square

inch times square root inch)Magnetic Conversions:1 T = 104 G (gauss)1 A/m = 1.257·10-2 Oe (oersted)1 Wb = 108 Maxwell


ADVERTISERS’INDEX

Need more information on products or services seen in this issue? Complete the form below and fax to the advertiser(s) of your choice. Fax numbers are listed in the advertisers’ index above.

To:___________________________________ Fax #: ____________________________________________________________________

Company: _______________________________________________________________________________________________________

Please send me more information on: __________________________________________________________________________

__________________________________________________________________________________________________________________

as advertised in the __________ issue of the International Journal of Powder Metallurgy.

Please send information to:

Name: Title:______________________________________________________________________________________________________

Company: _______________________________________________________________________________________________________

Address: _________________________________________________________________________________________________________

City:____________________________ State:_______________ Postal Code: ____________________________________________

Country: _________________________________________________________________________________________________________

Phone:___________________ Fax:___________________ E-Mail: ______________________________________________________

ADVERTISER’S REQUEST FOR INFORMATION FAX FORMinternational journal of

powdermetallurgy

ACE IRON & METAL CO. INC._____________(269) 342-0185 _______________________________________________________________5

ACUPOWDER INTERNATIONAL, LLC _______(908) 851-4597 ___________www.acupowder.com _________________________________19

CERAMITEC 2009 ______________________(212) 262-6519 ___________www.ceramitec.de/en__________________________________8

GLOBAL TITANIUM _____________________(313) 366-5305 ___________www.globaltitanium.com ______________________________39

HOEGANAES CORPORATION _____________(856) 786-2574 ___________www.hoeganaes.com_________________INSIDE FRONT COVER

PIM INTERNATIONAL ___________________+44 (0)1743 369660 _______www.pim-international.com____________________________14

SCM METAL PRODUCTS, INC.____________(919) 544-7996 ___________www.scmmetals.com __________________INSIDE BACK COVER

QMP ________________________________(734) 953-0082 ___________www.qmp-powders.com ______________________BACK COVER

UNION PROCESS ______________________(330) 929-3034 ___________www.unionprocess.com ________________________________6

ADVERTISER FAX WEB SITE PAGE

e-ijpm: vol. 45/4 - cloud object storage | store ...s3.amazonaws.com/zanran_storage/ · 11 2009...

Documents