Transcript WATKINS - Chabot College

Engineering 45
Materials of
Engineering
- Introduction Bruce Mayer, PE
Licensed Electrical & Mechanical Engineer
[email protected]
Engineering-45: Materials of Engineering
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
Course 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
Engineering-45: Materials of Engineering
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
Class Q: Materials Engineering
& Technology → What is it?
 Investigating the Structures
& Properties of Materials
and Correlating these with
the Design or Engineering
or Technology Objectives
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
The Evolution of Materials
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
Materials Science & Engineering
 Materials are ENGINEERED Structures
• Not Black Boxes
 Basic Material Structure Has Many
Dimensions
Structural Feature
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
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Dimension (m)
>10-6
Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
Structure, Processing, & Properties
 PROPERTIES depend on STRUCTURE
• e.g.; The HARDNESS vs STRUCTURE of Steel
(d)
Hardness (BHN)
600
500
400
Ferrite +
Cementite
(a)
G10380 +
w/ Pearlite
200
100
0.01 0.1
4m
30m
Tempered
Martensite
 PROCESSING can
change STRUCTURE
1
10 100 1000
Cooling Rate (C/s)
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UNtempered
Martensite
(b)
300
30m
30m
(c)
• e.g., STRUCTURE vs
Cooling-Rate for Steel
Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
Classes of Materials
 From Chem1A Recall The Periodic Table of Elements
Polymers
Ceramics
SemiConductors
Metals
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
Metals
 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)
Engineering-45: Materials of Engineering
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
Ceramics
 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
Engineering-45: Materials of Engineering
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
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
Engineering-45: Materials of Engineering
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
Polymers
 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
Engineering-45: Materials of Engineering
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
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
Engineering-45: Materials of Engineering
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
SemiConductors
 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
Engineering-45: Materials of Engineering
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
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
Engineering-45: Materials of Engineering
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
Composites
 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
Engineering-45: Materials of Engineering
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
BioMaterials
 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
Engineering-45: Materials of Engineering
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
Smart 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
Engineering-45: Materials of Engineering
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
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
Engineering-45: Materials of Engineering
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
NanoTechnology
 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
Engineering-45: Materials of Engineering
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
Materials
Application
Chain
Processing
Structure
Properties
Performance
Selection
Field Application

SELECTION is the Critical Step
for Physical-Design Engineers
Engineering-45: Materials of Engineering
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
Materials Selection
1. Pick APPLICATION → Determine
Required PROPERTIES
•
Properties
•
•
•
•
•
•
Mechanical
Electrical
Thermal
Magnetic
Optical
Deteriorative
•
•
•
•
Corrosion
Wear
Ageing
UV exposure, etc.
Engineering-45: Materials of Engineering
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
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
Engineering-45: Materials of Engineering
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
Materials 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.
Engineering-45: Materials of Engineering
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
Material Properties
Property
Stimulus
Result
Mechanical
load
deformation,
stress, strain
Envt./Chemical
chemicals, temp
corrosion
Terms
“structural matls”
modulus/stiffness,
strength, toughness
passivity, pollution
(aqueous solution)
“electronic matl.s”
semiconductors,
resistivity, dielectric
magnets, hysteresis,
moments
Electrical
electrical field
conductivity
Magnetic
magnetic field
magnetism
Thermal
heat
conductivity
heat capacity,
thermal expansion
Optical
radiation
(em, light)
color,
transparency
index of refraction,
reflectivity
 Material performance depends on material properties
Engineering-45: Materials of Engineering
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
Basic Material Properties
Mechanical properties
Thermal expansion
General
Density , kg/m3
Expense:
Cost/kg Cm, $/kg
o
Mechanical
Ductile materials
Strength:
Elastic limit y , MPa
Fracture strength: Tensile strength ts , MPa
Brittleness: Fracture toughness KIc , MPa·m1/2
Young’s modulus, E
x
Conduction: Thermal conductivity , W/m·K
 Tensile (fracture)

Specific Heat (Capacity), cp or cv, J/kg·K
ts

Young’s
modulus, E
Electrical
Conductor? Insulator? Conductivity σ, S/m
Dielectric Capacity, F/m
Strain 
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Thermal conduction
Thermal
Brittle materials
strength,
Expansion
coefficient, 
Temperature, T
Expansion: Expansion coeff. , 1/K
Strain 
Stress 
Young’s modulus E, GPa
To
T1
Area A
Q joules/sec
Heat flux, Q/A
Stress 
Elastic limit,y
Stiffness:

Thermal strain 
Weight:
Thermal
conductivity, 
(T1 -T0)/x
Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
Mechanical Properties Example
Stiff
Strong
Tough
Light
All OK !
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
Engineering-45: Materials of Engineering
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
Electrical Structure/Properties
 Electrical Resistivity of Copper
 Note: Resistivity,
= 1/Conductivity
• Resistivity → ρ
(Ω-m)
• Conductivity → σ
(S/m)
 Adding “impurity” atoms to Cu increases resistivity
 Deforming Cu increases resistivity
Engineering-45: Materials of Engineering
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
Thermal Structure/Properties
 THERMAL Conductivity of Copper
 Adding “impurity” atoms to Cu (zinc to make a
BRASS) Decreases Thermal conductivity
Engineering-45: Materials of Engineering
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
Magnetic Structure/Properties
 Magnetic Permeability vs. Composition for Iron
 Adding 3 atomic % Si makes Fe a Much BETTER
magnetic recording medium
Engineering-45: Materials of Engineering
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
Optical Structure/Properties
 Aluminum Oxide Light Transmittance
single crystal
polycrystal:
low porosity
polycrystal:
high porosity
 may be transparent, translucent, or opaque
depending on the material structure
Engineering-45: Materials of Engineering
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
Deteriorative Structure/Properties
 SaltWater and
STRESS can Cause
Cracks in Metals
 Heat treatment:
slows crack
formation speed in
salt-water exposed
metal
Engineering-45: Materials of Engineering
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
Materials Information for Design
The 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.
Stat/Math
analysis
Data
capture
Selection of
material and process
Economic analysis
and business case
Mechanical Properties
Bulk Modulus
Compressive Strength
Ductility
Elastic Limit
Endurance Limit
Fracture Toughness
Hardness
Loss Coefficient
Modulus of Rupture
Poisson's Ratio
Shear Modulus
Tensile Strength
Young's Modulus
Test
Test data
Characterization
Engineering-45: Materials of Engineering
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4.1 55 0.06 40 24 2.3 100 0.00950 0.38 0.85 45 2.5 -
4.6 GPa
60 MPa
0.07
45 MPa
27 MPa
2.6 MPa.m1/2
140 MPa
0.026
55 MPa
0.42
0.95 GPa
48 MPa
2.8 GPa
Design data
$
Potential
applications
Successful
applications
Selection and implementation
Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
© 2002, M.F. Ashby and D. Cebon
Goals of Matls Engineering & Technology
 Select the Best
Material for the Job
 Understand InterRelationships of
•
•
•
•
 If something goes
wrong (“failure”)
• Understand Why
• Fix & Prevent
processing
structure
properties
performance
Performance
Processing
Structure
Properties
 Open new design opportunities with new materials
Engineering-45: Materials of Engineering
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
WhiteBoard Work
 Problem Summary Here
• List problem
– Features
– Constraints
– Criteria
– Goals
Engineering-45: Materials of Engineering
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
IBM-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.
Engineering-45: Materials of Engineering
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt
IBM-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/studen
topps/nsfstudent/NSFapplic.html
Engineering-45: Materials of Engineering
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Bruce Mayer, PE
[email protected] • ENGR-45_Lec-01_Intro.ppt