Upload
piers-powers
View
217
Download
1
Embed Size (px)
Citation preview
[email protected] • ENGR-45_Lec-01_Intro.ppt1
Bruce Mayer, PE Engineering-45: Materials of Engineering
Bruce Mayer, PELicensed Electrical & Mechanical Engineer
Engineering 45
Materials of Materials of EngineeringEngineering
- Introduction - Introduction --
[email protected] • ENGR-45_Lec-01_Intro.ppt2
Bruce Mayer, PE Engineering-45: Materials of Engineering
Course Goals SummarizedCourse Goals Summarized
Use the right material for the job• i.e.; Materials Application
Understand the relation between PROPERTIES, STRUCTURE, and PROCESSING• i.e.; Materials Science & Engineering
Recognize new design opportunities offered by materials selection• i.e.; Physical-Design Innovation
[email protected] • ENGR-45_Lec-01_Intro.ppt3
Bruce Mayer, PE Engineering-45: Materials of Engineering
Class Q: Materials Engineering Class Q: Materials Engineering & Technology → What is it?& Technology → What is it?
Investigating the Structures & Properties of Materials and Correlating these with the Design or Engineering or Technology Objectives
[email protected] • ENGR-45_Lec-01_Intro.ppt4
Bruce Mayer, PE Engineering-45: Materials of Engineering
The Evolution of MaterialsThe Evolution of Materials
[email protected] • ENGR-45_Lec-01_Intro.ppt5
Bruce Mayer, PE Engineering-45: Materials of Engineering
Materials Science & EngineeringMaterials Science & Engineering
Materials are ENGINEERED Structures• Not Black Boxes
Basic Material Structure Has Many Dimensions
Structural Feature Dimension (m)Atomic Bonding <10-10
Missing/Extra Atoms 10-10
Crystals (Ordered Atoms) 10-10 - 10-1
Second Phase Particles 10-8 - 10-4
Crystal Texturing >10-6
[email protected] • ENGR-45_Lec-01_Intro.ppt6
Bruce Mayer, PE Engineering-45: Materials of Engineering
Structure, Processing, & PropertiesStructure, Processing, & Properties PROPERTIES depend on STRUCTURE
• e.g.; The HARDNESS vs STRUCTURE of Steel
Cooling Rate (C/s)
100
200
300
400
500
600
0.01 0.1 1 10 100 1000
(a)
30m
(b)
30m
(d)
30m(c)
4m
Har
dnes
s (B
HN
)
PROCESSING can change STRUCTURE• e.g., STRUCTURE vs
Cooling-Rate for Steel
TemperedMartensite
UNtemperedMartensite
Ferrite +Cementite
G10380 +w/ Pearlite
[email protected] • ENGR-45_Lec-01_Intro.ppt7
Bruce Mayer, PE Engineering-45: Materials of Engineering
Classes of MaterialsClasses of Materials From Chem1A Recall The Periodic Table of Elements
Metals
CeramicsPolymers
SemiConductors
[email protected] • ENGR-45_Lec-01_Intro.ppt8
Bruce Mayer, PE Engineering-45: Materials of Engineering
MetalsMetals
May be Pure or Compounds (Alloys)• Along with Polymers The Most Common
Everyday Material
• Typically from the 1st Row of Transition Metals in Periodic Table (Fe, Cu, Ni, etc.)
• Have LARGE Numbers of NonBound Electrons – Makes them Good Electrical & Thermal
CONDUCTORS
• Strong but Deformable (Ductile)
[email protected] • ENGR-45_Lec-01_Intro.ppt9
Bruce Mayer, PE Engineering-45: Materials of Engineering
CeramicsCeramics
Basic Composition is the MINERAL Form of a Metal• Very Few Metals Exist in
PURE Form in Nature– Most That Do are Very Rare, e.g., Gold
Ceramics are Compounds of Metals and• Oxygen → Oxides (most Ceramics)
• Carbon → Carbides
• Nitrogen → Nitrides
[email protected] • ENGR-45_Lec-01_Intro.ppt10
Bruce Mayer, PE Engineering-45: Materials of Engineering
Ceramics cont.Ceramics cont.
Some Typical Properties• HARD & BRITTLE
• HIGHEST Temperature Resistance– Thoria (Thorium Oxide) Max Temp 3000 K
• Llttle Temperature-SHOCK Resistance
• Corrosion Resistant
• Electrically Resistive (Insulative)
• Difficult to Join– Do Not Weld
[email protected] • ENGR-45_Lec-01_Intro.ppt11
Bruce Mayer, PE Engineering-45: Materials of Engineering
PolymersPolymers
Many ChemUnits• MER A Basic Chemical Unit
• POLY Many
Chemical Compounds composed of, in VAST Majority, CARBON & HYDROGEN• Modified by the Presence of Other Elements
– O, Si, F, Cl, N, many others
Commonly Referred to as PLASTIC and/or (synthetic) RUBBER
[email protected] • ENGR-45_Lec-01_Intro.ppt12
Bruce Mayer, PE Engineering-45: Materials of Engineering
Polymers cont.Polymers cont.
Some Typical Properties• Very LightWeight
• Very Corrosion Resistant– Best of ANY Class of Material
• Little, if any, Hi/Lo Temperature Resistance
• Little Structural Strength
• Very Deformable (ductile/flexible)
• Lowest $-Cost:Volume Ratio for Any Class of Material
[email protected] • ENGR-45_Lec-01_Intro.ppt13
Bruce Mayer, PE Engineering-45: Materials of Engineering
SemiConductorsSemiConductors
May be made CONDUCTIVE or INSULATIVE (or Something in-between) by the Addition of Miniscule Amounts of IMPURITIES• Current Techniques Allow Precise Control
over the AMOUNT and LOCATION of the Impurities
Semiconductors are Very Important Electronic Device Materials
[email protected] • ENGR-45_Lec-01_Intro.ppt14
Bruce Mayer, PE Engineering-45: Materials of Engineering
Semiconductors cont.Semiconductors cont.
Most SOLID STATE (no moving parts) Electronic Devices are Semiconductors
Major applications for Semi Transistors• Voltage Amplifiers
• On/Off switches
Additional Advantage: Semiconductor Electronic Devices can be constructed at Extremely SMALL Scales
SILICON is the Most Widely Used
[email protected] • ENGR-45_Lec-01_Intro.ppt15
Bruce Mayer, PE Engineering-45: Materials of Engineering
CompositesComposites
Materials that Consist of More than One Material Type• Goal is to Combine the Best
Features of Multiple Materials
Some Examples• FiberGlass = Glass (ceramic) + Polymer
– Strength + Flexibilty
• ReInforced Concrete = Steel + Concrete– Tension-Strength + Compression-Strength
[email protected] • ENGR-45_Lec-01_Intro.ppt16
Bruce Mayer, PE Engineering-45: Materials of Engineering
BioMaterialsBioMaterials
Defined as Those Materials Which Are compatible with Human Tissue• Classic Example = Stainless Steels
used For Bone repair (Screws, Staples, Plates, Hip-Joints)
At least a few of ALL other Classes of Materials are BioCompatible• Including Silicon
[email protected] • ENGR-45_Lec-01_Intro.ppt17
Bruce Mayer, PE Engineering-45: Materials of Engineering
Smart MaterialsSmart Materials
Smart Materials Materials That Can Sense Changes in the Environment and Respond with a Material Shape/Property Change• Example: "smart" materials that can be
attached to, or embedded in, structural systems – enable the structure to sense disturbances,
process the information and through commands to actuators, to accomplish some beneficial reaction
[email protected] • ENGR-45_Lec-01_Intro.ppt18
Bruce Mayer, PE Engineering-45: Materials of Engineering
Smart Materials, cont.Smart Materials, cont. Potential Applications – Structural Systems
• Machine Tools - Improve precision and increase productivity by controlling chatter
• Flexible robotics - enable faster motion with greater accuracy
• Photo-lithography - Enable the manufacture of smaller micro-electronic circuits by controlling vibration in the photo-lithography circuit printing process
• Biomechanical & Biomedical - artificial muscles, drug delivery systems and other assistive technologies
• Process Control - e. g., on/off shape control of solar reflectors or aerodynamic surfaces
[email protected] • ENGR-45_Lec-01_Intro.ppt19
Bruce Mayer, PE Engineering-45: Materials of Engineering
NanoTechnologyNanoTechnology
Most Materials are Statistical Devices• i.e., Their Properties are the Average of a
LARGE Number of Atoms or Molecules– A change in a Single NanoScale Particle does
NOT affect Material Characteristics
NanoScale Materials, on the Other hand, are built ONE NanoParticle at a time• Properties Can be PRECISELY Tailored
[email protected] • ENGR-45_Lec-01_Intro.ppt20
Bruce Mayer, PE Engineering-45: Materials of Engineering
MaterialsMaterialsApplicationApplicationChainChain
Processing
Structure
Properties
Performance
Selection
Field Application SELECTION is the Critical Step
for Physical-Design Engineers
[email protected] • ENGR-45_Lec-01_Intro.ppt21
Bruce Mayer, PE Engineering-45: Materials of Engineering
Materials SelectionMaterials Selection
1. Pick APPLICATION → Determine Required PROPERTIES
• Properties• Mechanical• Electrical• Thermal• Magnetic• Optical• Deteriorative
• Corrosion• Wear• Ageing• UV exposure, etc.
[email protected] • ENGR-45_Lec-01_Intro.ppt22
Bruce Mayer, PE Engineering-45: Materials of Engineering
Materials Selection cont.Materials Selection cont.
2. PROPERTIES → Identify candidate Material(s)
• Properties Follow• COMPOSITION as Identified by
CHEMICAL CONTENT• STRUCTURE as Determined by
Material-Formation Processing; e.g.:• Amorphous vs PolyCrystalline vs FullyCrystalline• Second (and perhaps Tertiary) Phases
• Type• Quantity• Size• Distribution
[email protected] • ENGR-45_Lec-01_Intro.ppt23
Bruce Mayer, PE Engineering-45: Materials of Engineering
Materials Selection cont.2Materials Selection cont.2
3. MATERIAL → Identify PROCESSING to Obtain Required Structure, and Hence Properties
• Processing Changes STRUCTURE or SHAPE, but NOT Composition• e.g.:
• Casting • Sintering• Thin Film Deposition (CVD, Sputtering, Evap, etc.)• Forming or other Cold-Working• Joining• Annealing, Tempering, or other Heat Treatment• Etc.
[email protected] • ENGR-45_Lec-01_Intro.ppt24
Bruce Mayer, PE Engineering-45: Materials of Engineering
Material PropertiesMaterial Properties
Mechanical load deformation, stress, strain
“structural matls” modulus/stiffness, strength, toughness
Envt./Chemical chemicals, temp (aqueous solution)
corrosion passivity, pollution
Electrical electrical field conductivity “electronic matl.s” semiconductors, resistivity, dielectric
Magnetic magnetic field magnetism magnets, hysteresis, moments
Thermal heat conductivity heat capacity, thermal expansion
Optical radiation (em, light)
color, transparency
index of refraction, reflectivity
Property Stimulus Result Terms
Material performance depends on material properties
[email protected] • ENGR-45_Lec-01_Intro.ppt25
Bruce Mayer, PE Engineering-45: Materials of Engineering
Basic Material PropertiesBasic Material Properties
General
Weight: Density , kg/m3
Expense: Cost/kg Cm, $/kg
Mechanical
Stiffness: Young’s modulus E, GPa
Strength: Elastic limit y , MPa
Fracture strength: Tensile strength ts , MPa
Brittleness: Fracture toughness KIc , MPa·m1/2
Thermal
Expansion: Expansion coeff. , 1/K
Conduction: Thermal conductivity , W/m·K
Specific Heat (Capacity), cp or cv, J/kg·K
Electrical
Conductor? Insulator? Conductivity σ, S/m
Dielectric Capacity, F/m
Young’s modulus, E
Elastic limit, y
Strain
Str
ess
Ductile materials
Brittle materials
Young’s modulus, E
Tensile (fracture) strength, ts
Strain
Str
ess
Thermal expansion
o
Expansion coefficient,
Temperature, T
Th
erm
al s
tra
in
x
T1 To
Q joules/secArea A
Thermal conduction
Mechanical properties
Thermal conductivity,
(T1 -T0)/x
He
at
flux,
Q/A
[email protected] • ENGR-45_Lec-01_Intro.ppt26
Bruce Mayer, PE Engineering-45: Materials of Engineering
Mechanical Properties ExampleMechanical Properties ExampleStiffStrongToughLight
Not stiff enough (need bigger E) modulus of elasticity
Not strong enough (need bigger y ) yield strength
Not tough enough (need bigger KIc)fracture toughness
Too heavy (need lower ) density
All OK !
[email protected] • ENGR-45_Lec-01_Intro.ppt27
Bruce Mayer, PE Engineering-45: Materials of Engineering
Electrical Structure/PropertiesElectrical Structure/Properties Electrical Resistivity of Copper
Adding “impurity” atoms to Cu increases resistivity Deforming Cu increases resistivity
T (°C)-200 -100 0
Cu + 3.32 at%Ni
Cu + 2.16 at%Ni
deformed Cu + 1.12 at%Ni
1
2
3
4
5
6
Resi
stiv
ity,
(1
0-8 O
hm
-m)
0
Cu + 1.12 at%Ni
“Pure” Cu
Note: Resistivity, = 1/Conductivity• Resistivity → ρ
(Ω-m)
• Conductivity → σ (S/m)
[email protected] • ENGR-45_Lec-01_Intro.ppt28
Bruce Mayer, PE Engineering-45: Materials of Engineering
Thermal Structure/PropertiesThermal Structure/Properties THERMAL Conductivity of Copper
Adding “impurity” atoms to Cu (zinc to make a BRASS) Decreases Thermal conductivity
Composition (wt%Zinc)Therm
al C
onduct
ivit
y
(W/m
-K)
400
300
200
100
00 10 20 30 40
[email protected] • ENGR-45_Lec-01_Intro.ppt29
Bruce Mayer, PE Engineering-45: Materials of Engineering
Magnetic Structure/PropertiesMagnetic Structure/Properties Magnetic Permeability vs. Composition for Iron
Adding 3 atomic % Si makes Fe a Much BETTER magnetic recording medium
Magnetic FieldMagneti
zati
onFe+3%Si
Fe
[email protected] • ENGR-45_Lec-01_Intro.ppt30
Bruce Mayer, PE Engineering-45: Materials of Engineering
Optical Structure/PropertiesOptical Structure/Properties Aluminum Oxide Light Transmittance
may be transparent, translucent, or opaque depending on the material structure
single crystalpolycrystal:low porosity
polycrystal:high porosity
[email protected] • ENGR-45_Lec-01_Intro.ppt31
Bruce Mayer, PE Engineering-45: Materials of Engineering
Deteriorative Structure/PropertiesDeteriorative Structure/Properties SaltWater and
STRESS can Cause Cracks in Metals
Heat treatment: slows crack formation speed in salt-water exposed metal
“held at 160C for 1hr before testing”
increasing loadcrack
sp
eed
(m
/s)
“as-is”
10-10
10-8
Alloy 7178 tested in saturated aqueous NaCl solution at 23C
[email protected] • ENGR-45_Lec-01_Intro.ppt32
Bruce Mayer, PE Engineering-45: Materials of Engineering
Materials Information for DesignMaterials Information for DesignThe goal of design:“To create products that perform their function effectively, safely, at acceptable cost”
What do we need to know about materials to do this? More than just test data.
Test Test data
Data capture
Stat/Mathanalysis
Design data Successful applications
$
Economic analysisand business case
Selection ofmaterial and process
Potential applications
Mechanical Properties
Bulk Modulus 4.1 - 4.6 GPaCompressive Strength 55 - 60 MPaDuctility 0.06 - 0.07Elastic Limit 40 - 45 MPaEndurance Limit 24 - 27 MPaFracture Toughness 2.3 - 2.6 MPa.m1/2
Hardness 100 - 140 MPaLoss Coefficient 0.009- 0.026Modulus of Rupture 50 - 55 MPaPoisson's Ratio 0.38 - 0.42Shear Modulus 0.85 - 0.95 GPaTensile Strength 45 - 48 MPaYoung's Modulus 2.5 - 2.8 GPa
Characterization Selection and implementation
© 2002, M.F. Ashby and D. Cebon
[email protected] • ENGR-45_Lec-01_Intro.ppt33
Bruce Mayer, PE Engineering-45: Materials of Engineering
Goals of Matls Engineering & TechnologyGoals of Matls Engineering & Technology
Select the Best Material for the Job
If something goes wrong (“failure”)• Understand Why
• Fix & Prevent
Understand Inter-Relationships of• processing
• structure
• properties
• performance
Structure
Processing
Properties
Performance
Open new design opportunities with new materials
[email protected] • ENGR-45_Lec-01_Intro.ppt34
Bruce Mayer, PE Engineering-45: Materials of Engineering
WhiteBoard WorkWhiteBoard Work
Problem Summary Here• List problem
– Features
– Constraints
– Criteria
– Goals
[email protected] • ENGR-45_Lec-01_Intro.ppt35
Bruce Mayer, PE Engineering-45: Materials of Engineering
IBM-Almaden InternshipIBM-Almaden Internship Target Audience
• Projects and the program are designed for sophomores and juniors with majors in chemistry, physics, chemical engineering and related sciences
Program Details Duration: 10 weeks, beginning June 7 or June 21, 2004. Stipend: Students $4500 for 10 weeks (not bad...). Eligibility: Undergraduate (pre-graduate school) standing,
with preferably two years of chemistry. Requirements vary by project, but outstanding candidates at any level and technical major in science or engineering are encouraged to apply. Preference is given to chemistry, chemical engineering, and materials science majors. Participants must be citizens or permanent legal residents of the US.
[email protected] • ENGR-45_Lec-01_Intro.ppt36
Bruce Mayer, PE Engineering-45: Materials of Engineering
IBM-Almaden InternshipIBM-Almaden Internship
The BAD News → A Pretty Nasty Set of Application Documents• Two App Forms
• Two Letters of Req– I can Help
• Personal Essay
For the Forms see• http://www.almaden.ibm.com/st/info/
studentopps/nsfstudent/NSFapplic.html