Types of Material

IE 351

Lecture 3

Engineering Materials

Classification of Materials

• Metals

• Ceramics

• Polymers

• Composite Materials

Further Classification

• Metals– Ferrous– Non-ferrous– Super alloys

• Ceramics– Traditional ceramics– New ceramics– Glass

Further Classification

• Polymers– Thermoplastics– Thermosets– Elastomers

• Composite Materials– Metal Matrix Composites– Ceramic Matrix Composites– Polymer Matrix Composites

Metals

• Ferrous Metals– Cast irons– Steels

• Non-ferrous metals– Aluminum and its alloys– Copper and its alloys– Magnesium and its alloys– Nickel and its alloys– Titanium and its alloys

Metals

• Ferrous Metals– Cast irons

– Steels

• Superalloys– Iron-based

– Nickel-based

– Cobalt-based

• Non-ferrous metals– Aluminum and its alloys

– Copper and its alloys

– Magnesium and its alloys

– Nickel and its alloys

– Titanium and its alloys

– Zinc and its alloys

– Lead & Tin

– Refractory metals

– Precious metals

Heat Treatment of Metals

• Annealing– Full annealing– Normalising (faster rate of cooling)– Recovery annealing (longer holding time, slower

rate of cooling,)– Stress relieving (lower temperature)

• Martensite formation in steel– Austenitizing (conversion to austenite)– Quenching (control cooling rate– Tempering (reduce brittleness)

Heat Treatment of Metals

• Precipitation hardening– Solution treatment (-phase conversion)– quenching– precipitation treatment (aging)

• Surface hardening– Carburizing– Nitriding– Carbonitriding– Chromizing and Boronizing

Heat Treatment of Steel

Precipitation Hardening

Solution treatment

Quenching

Precipitation treatment

Furnaces for Heat Treatment

• Fuel fire furnaces– gas– oil

• Electric furnaces– batch furnaces

• box furnaces - door

• car-bottom furnaces - track for moving large parts

• bell-type furnaces - cover/bell lifted by gantry crane

– continuous furnaces

Furnaces for Heat Treatment

• Vacuum furnaces

• Salt-bath furnaces

• Fluidized-bed furnaces

Some of the furnaces have special atmosphere requirements, such as carbon- and nitrogen- rich atmosphere.

Surface Hardening Methods

• Flame hardening

• Induction heating

• High-frequency resistance heating

• Electron beam heating

• Laser beam heating

Surface Hardening Methods

Inductionheating

High frequencyresistanceheating

Ceramics

• Traditional ceramics– clays: kaolinite– silica: quartz, sandstone– alumina– silicon carbide

• New ceramics– oxide ceramics : alumina– carbides : silicon carbide, titanium carbide, etc.– nitrides : silicon nitride, boron nitiride, etc.

Glass

• Glass products– window glass– containers– light bulb glass– laboratory glass– glass fibers– optical glass

• Glass ceramics - polycrystalline structure

Polymers

• Thermoplastics - reversible in phase by heating and cooling. Solid phase at room temperature and liquid phase at elevated temperature.

• Thermosets - irreversible in phase by heating and cooling. Change to liquid phase when heated, then follow with an irreversible exothermic chemical reaction. Remain in solid phase subsequently.

• Elastomers - Rubbers

Thermoplastics

– Acetals– Acrylics - PMMA– Acrylonitrile-Butadiene-Styrene - ABS– Cellulosics– Fluoropolymers - PTFE , Teflon– Polyamides (PA) - Nylons, Kevlar– Polysters - PET– Polyethylene (PE) - HDPE, LDPE– Polypropylene (PP)– Polystyrene (PS)– Polyvinyl chloride (PVC)

Thermosets

• Amino resins

• Epoxies

• Phenolics

• Polyesters

• Polyurethanes

• Silicones

Elastomers

• Natural rubber

• Synthetic rubbers– butadiene rubber– butyl rubber– chloroprene rubber– ethylene-propylene rubber– isoprene rubber– nitrile rubber– polyurethanes– silicones– styrene-butadiene rubber– thermoplastic elastomers

Composite Materials

• Metal Matrix Composites (MMC)Mixture of ceramics and metals reinforced by strong,

high-stiffness fibers

• Ceramic Matrix Composites (CMC)Ceramics such as aluminum oxide and silicon carbide

embedded with fibers for improved properties, especially high temperature applications.

• Polymer Matrix Composites (PMC)Thermosets or thermoplastics mixed with fiber

reinforcement or powder.

Composite Materials

1D fibre

Woven fabric

Random fibre

Composite Materials

Material Selection

Ashby,: Material Selection in Mechanical Design

Taxonomy of Materials Selection

Ashby,: Material Selection in Mechanical Design

Material Specification

• Chemical composition

• Mechanical properties – Strength, hardness (under various conditions: temperature, humidity, pressure)

• Physical properties – density, optical, electrical, magnetic

• Environmental – green, recycling

Typical Selection of Carbon and Alloy Steels for Various Applications

TABLE 5.1Product Steel Product SteelAircraft forgings,

tubing, fittingsAutomobile bodiesAxlesBall bearings and racesBoltsCamshaftsChains (transmission)Coil springsConnecting rodsCrankshafts (forged)

4140, 8740

10101040, 4140521001035, 4042, 48151020, 10403135, 314040631040, 3141, 43401045, 1145, 3135, 3140

Differential gearsGears (car and truck)Landing gearLock washersNutsRailroad rails and wheelsSprings (coil)Springs (leaf)TubingWireWire (music)

40234027, 40324140, 4340, 87401060313010801095, 4063, 61501085, 4063, 9260, 615010401045, 10551085

Mechanical Properties of Selected Carbon and Alloy Steels in Various Conditions

TABLE 5.2 Typical Mechanical Properties of Selected Carbon and Alloy Steels in the Hot-Rolled,Normalized, and Annealed ConditionAISI Condition Ultimate

tensilestrength(MPa)

YieldStrength(MPa)

Elongation in50 mm (%)

Reduction ofarea (%)

Hardness(HB)

1020

1080

3140

4340

8620

As-rolledNormalizedAnnealedAs-rolled

NormalizedAnnealed

NormalizedAnnealed

NormalizedAnnealed

NormalizedAnnealed

448441393

1010965615891689

1279744632536

346330294586524375599422861472385357

363536121124192412222631

596766172045575036495962

143131111293293174262197363217183149

AISI Designation for High-Strength Sheet Steel

TABLE 5.3Yield Strength Chemical

CompositionDeoxidation

Practice

psi x 103 MPa

35404550607080

100120140

240275310350415485550690830970

S = structural alloy

X = low alloy

W = weathering

D = dual phase

F = killed plus sulfide inclusion control

K = killed

O = nonkilled

Room-Temperature Mechanical Properties and Applications of Annealed Stainless Steels

TABLE 5.4 Room-Temperature Mechanical Properties and Typical Applications of Selected AnnealedStainless Steels

AISI(UNS)

Ultimatetensile

strength(MPa)

Yieldstrength(MPa)

Elongationin 50 mm

(%) Characteristics and typical applications303(S30300)

550–620 240–260 53–50 Screw machine products, shafts, valves, bolts,bushings, and nuts; aircraft fittings; bolts; nuts;rivets; screws; studs.

304(S30400)

565–620 240–290 60–55 Chemical and food processing equipment,brewing equipment, cryogenic vessels, gutters,downspouts, and flashings.

316(S31600)

550–590 210–290 60–55 High corrosion resistance and high creep strength.Chemical and pulp handling equipment,photographic equipment, brandy vats, fertilizerparts, ketchup cooking kettles, and yeast tubs.

410(S41000)

480–520 240–310 35–25 Machine parts, pump shafts, bolts, bushings, coalchutes, cutlery, tackle, hardware, jet engine parts,mining machinery, rifle barrels, screws, andvalves.

416(S41600)

480–520 275 30–20 Aircraft fittings, bolts, nuts, fire extinguisherinserts, rivets, and screws.

Basic Types of Tool and Die Steels

TABLE 5.5Type AISIHigh speed

Hot work

Cold work

Shock resisting

Mold steels

Special purpose

Water hardening

M (molybdenum base)T (tungsten base)H1 to H19 (chromium base)H20 to H39 (tungsten base)H40 to H59 (molybdenum base)D (high carbon, high chromium)A (medium alloy, air hardening)O (oil hardening)SP1 to P19 (low carbon)P20 to P39 (others)L (low alloy)F (carbon-tungsten)W

Processing and Service Characteristics of Common Tool and Die Steels

TABLE 5.6 Processing and Service Characteristics of Common Tool and Die Steels

AISIdesignation

Resistance todecarburization

Resistance tocracking

Approximatehardness(HRC) Machinability Toughness

Resistance tosoftening

Resistance towear

M2 Medium Medium 60–65 Medium Low Very high Very highT1 High High 60–65 Medium Low Very high Very highT5 Low Medium 60–65 Medium Low Highest Very highH11, 12, 13 Medium Highest 38–55 Medium to high Very high High MediumA2 Medium Highest 57–62 Medium Medium High HighA9 Medium Highest 35–56 Medium High High Medium to

highD2 Medium Highest 54–61 Low Low High High to very

highD3 Medium High 54–61 Low Low High Very highH21 Medium High 36–54 Medium High High Medium to

highH26 Medium High 43–58 Medium Medium Very high HighP20 High High 28–37 Medium to high High Low Low to

mediumP21 High Highest 30–40 Medium Medium Medium MediumW1, W2 Highest Medium 50–64 Highest High Low Low to

medium

Source: Adapted from Tool Steels, American Iron and Steel Institute, 1978.