rjm, 8/7/06all photos and figures - copyright, prentice hall what is this class??? applied material...

RJM, 8/7/06 All photos and figures - Copyright, Prentice Hall

What is this Class???

• Applied material selection course– Some material science (text)

• Chemistry and Metallurgy

– Some material selection software (lab using CES software)

– A little corrosion and failure analysis (text and lab)

– + Capstone Projects!!

Goal: Intelligently select materials for design!!!


Chapter 1 – The Importance of Engineering MaterialsChapter 2 – Forming Engineering Materials from the Elements

• Origin of Engineering Materials

• The Periodic Table of Elements

• Overview: Metals, Ceramics, Polymers and Composites


History – the evolution of materials

The expansion of the materials world

James Stuart, Professor of Engineering at Cambridge

1875 - 1890

No polymers – now over 45,000

• Today: > 160,000 engineering materials• Creates two needs:

1 Education – how best to teach materials?

2 Industry – how manage materials information, consistency, etc.. ?

No light alloys – now several thousand

No composites – now hundreds ……

• In his day: a few hundred materials

Think about how materials impacted your life today, quality of life, drive to work/school, etc…

Composite wood, new thin glass for LCD/phone displays, semiconductors, diamond composite rock drills for deep sea drilling, new Mg alloys for automotive wheels, new inconel alloys for Yucca Mountain nuclear waste site, etc……………….


A Study in Polymers!!Football Helmet – 7 layers of various polymers:

Butyl elastomer bonded to g/f nylon

Composite mask (RTM)


Flight bars – PUR, abrasion resistance in extremely hostile environment

Drill Bit Isolators – high strength elastomer bonded to 4140 HT, carbide bitCaster wheel –

perfect marriage of steel, thermoplastic and elastomer


Seismic Mount (QC-19191)

Bearing Plate

Upright

Box Fabrication (Fail Safe)

Cross-Aisle

Down-Aisle

Seismic Isolation System:


Teaching materials to engineering students

Engineers make things. They make them out of materials, using processes.

The philosophy

The CES EduPack provides the resources to achieve this and gives students a tool they can use in their later profession (like CAD or FE tools)

What do they need to know to do this successfully?

• A perspective of the world of materials and processes

An ability to select those that best meet requirements of a design

Access to information and tools for comparison and selection

An understanding material properties and their origins


Mechanical properties illustrated (Ashby, 2005)

StiffStrongToughLight

Not stiff enough (need bigger E)

Not strong enough (need bigger y )

Not tough enough (need bigger Kic)

Too heavy (need lower )

All OK !

Need to improve on the selection of materials


Material Classifications (4 basic families):

• Metals • Ceramics

• Polymers • Composites

Applications: building frame, autos, heavy equipment, etc.

Key: cheap, strong and ductile, easily fabricated!!

Applications: Electronics, cutting tools, glass, building materials, etc.

Key: Extremely hard w/ high temp capability (little thermal expansion)

Applications: packaging, medical equipment, moderate load carrying applications, etc.

Key: Cheap, reasonably strong, variety of materials

Applications: Autos, aerospace, etc.

Key: high strength to weight ratio


Mechanical engineering

Ceramics,glasses

Hybrids, composites

Polymers,elastomers

Metals,alloys


Aerospace and motorsport

Hybrids, composites

Polymers,elastomers

Metals,alloys

Ceramics,glasses


Civil engineering and architecture

Hybrids, composites

Polymers,elastomers

Metals,alloys

Ceramics,glasses


Bio-engineering

Ceramics,glasses

Polymers,elastomers

Metals,alloys

Hybrids, composites


Product & industrial design

Hybrids, composites

Polymers,elastomers

Metals,alloys

Ceramics,glasses


Glass, stone, silicone carbide SiC

Wood/leather

CFRP, GFRP, aluminum silicone carbide Al/SiC


CES: Organising information: the MATERIALS TREE

Kingdom

Materials

Family

• Ceramics& glasses

• Metals & alloys

• Polymers & elastomers

• Hybrids

Class

Steels

Cu-alloys

Al-alloys

Ti-alloys

Ni-alloys

Zn-alloys

Member

1000

2000300040005000600070008000

A material record

Attributes

Density

Mechanical props.

Thermal props.

Electrical props.

Optical props.

Corrosion props.

Supporting information

-- specific

-- general

Density

Mechanical props.

Thermal props.

Electrical props.

Optical props.

Corrosion props.

Supporting information

-- specific

-- general

Structured

information

Unstructured

information


Optimized selection using charts

MρE1/2

23

MρE1/3

Results22 pass

Material 1 2230Material 2 2100Material 3 1950etc...

Ranked by Index /ρE1/2

1

MρE

Search area


Metals

Polymers

Ceramics

Composites

Chapter 1 Summary:


Chemistry Review (yuck)

• Just know basics…………………..


Basic Chemical Terms:

• Atom – smallest part of an element that retains the property of that element.

• Composed of neutrons, electrons, and protons.

• All matter composed of atoms bonded together in different patterns and different types of bonds.

• Elements – pure substance that CAN NOT be broken down to a simpler substance.

• 90 elements occur naturally in the earth’s crust.

• 120 total elements including laboratory synthesized elements.


Classification of Matter:

(contain carbon)

(not derived from living things)


•Atomic number – Total number of protons in the nucleus of an atom.

Periodic Table:

http://en.wikipedia.org/wiki/Periodic_table


Periodic Table:

• Best: http://www.webelements.com/• Elements can be broadly classified as: metals,

metalloids and nonmetals.• Metals – solid at room temperature (Except mercury),

malleable, ductile, strong, conduct electricity, 1/2/3 valence electrons in outer shell – much more!

• Nonmetals (total of 17) – poor conductors of heat, mostly insulators, tend to be brittle and fracture easily.

• Metalloids or semimetals – have some properties like metals (i.e. conduct electricity) but share other properties with non-metals.

See suplemental notes on course data disk for elements!!


*


Oxygen Atom


What we really care about are material properties!! From CES Unit 3 – The elements:

Elements 127 records for 111 elements 52 fields Periodic table properties Structural properties Mechanical properties Thermal properties Diffusion data Surface energies Electrical and superconducting props. Magnetic properties Nuclear properties Approximate cost

The Periodic Table


Using the Elements DB Explore how properties change across the Periodic Table


Relationships between properties (1)

Modulus and melting point


Engineering materials – the same dependence



Expansion coefficient and melting point



Electrical and thermal conductivities

Electrical and thermal conduction

Wiedemann-Franz law



Wiedemann-Franz law

CERAMICS ARE THE EXCEPTION!!!


1.3 Forming Engineering Materails from the Elements

222 2 OHOH moleculeswaterfourOH 24

Atoms must be balanced!

2

Recall: atoms tend to combine so their outer electron shell contains 8 electrons!!


1.4 The Solid State

Crystalline structures (i.e. metals) atoms are arranged in unit cells – 4 common cells shown above


Several cells form a crystal, if many crystals are growing in a melt at the same time, where they meet = grain boundry as shown below:


1.5 The Nature of Metals:

Characterized by:

1. Valence electrons of 1,2 or 3 – see periodic table

2. Primary bonding between electrons called metallic bonding:

Valence electrons not “bonded” to particular atom but shared and free to drift through the entire metal

3. Properties include: good conductors of electricity and heat, not transparent, quite strong yet deformable!


How do metals fail???

If bonds are strong and metal is brittle get cleavage failure

a. Cleavage:


How do metals fail???

b. Slip due to dislocations


b. Slip due to dislocations


How to Strengthen Metals

• Alloying (aka: Solid Solution Strengthening) – larger impurity atoms impede dislocation motion.

• Cold working – adding more dislocations actually impedes motion of all dislocations!!

• Heat Treating (aka: Precipitation hardening) impurity atoms coalesce in matrix and form barrier to dislocation movement.

• Dispersion Hardening (aka: Quench hardening) – fine particles impede dislocation movement.


How to strengthen metals:


1.6 Nature of ceramics:

Characterized by:

1. Compounds between metallic and non-metallic elements.

2. Frequently oxides, nitrides and carbides (i.e. silicon carbide – SpinWorks)

3. Very strong covalent (sharing of electrons) or ionic (transfer of electrons) bonds.

4. Properties include:

• Strong but brittle

• Low fracture toughness

• Good insulators of electricity BUT good conductor of heat (i.e. comparable to metals have reasonably high thermal conductivity, k) – this is unique to ceramics.

• Excellent high temp properties

• Low coef of thermal expansion


Electrical Resistance:

Ceramics = good electrical insulators, but…


Selection: one-property indices

Good conductors: metals and ceramics

Good insulators: polymer foams, cork, wood, cardboard….

Good thermal conductors!


1.6 Nature of ceramics:

Example: Aluminum Oxide, Al2O3


1.7 Nature of polymers:

Characterized by:

1. Organic compound (i.e. chemically based on carbon, hydrogen or other nonmetallic element)

2. Covalent bond between atoms

3. Long chain repeating molecular structures

4. Properties include low density, highly flexible

5. Broadly classified into three groups: thermosets, thermoplastics and elastomers.


1.8 Nature of Composites:

Characterized by:

1. Combination of two or more materials

2. Designed to display a combination of the best characteristics of each material i.e. fiberglass acquires strength from glass and flexibility from the polymer.

3. Can have:

• High strength to weight ratio

• Excellent corrosion resistance

4. Used in aircraft, boats, automotive, fishing pools, tennis rackets, etc

rjm, 8/7/06all photos and figures - copyright, prentice hall what is this class??? applied material...

Documents

prentice hall slide

figures copyright

selection of materials

materials information

world of materials

evolution of materials

prentice hall chapter

prentice hall history