MENG 201: Materials Science
Course Objective...
Introduce fundamental concepts in Materials Science
and Engineering
You will learn about:
• material structure
• how structure dictates properties
• how processing can change structure
This course will help you to:
• use materials properly
• realize new design opportunities with materials
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Historical perspective
• Civilization strongly linked with materials
• Stone age, ceramics age, bronze age, iron age, nuclear age,
information age
• The earliest humans had access to only a very limited number of
materials e.g: wood, clay, skin, stone
• Then man learned that material’s properties can be altered by
heat treatment and by addition of other substances (alloying)
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Why we study material science
1) Important to understand
capabilities and limitations of
materials.
The following are just a few examples
of catastrophic failure caused by a
lack of fundamental understanding
of materials, their properties, and
failure modes:
• Tacoma Narrows Bridge
Collapse (1940)
“poor design”
Liberty ships (WWII) BCC Fe (metal)
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Challenger (1986)
failure of an O-ring seal (polymer)
Hyatt Regency (KC)
walkway collapse (1981)
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Why we study material science
(2) An understanding of Materials Science helps us to design
better components, parts, devices, etc.
1) how do you make something stronger or lighter?
2) how do elements come together to form alloys?
3) why do some materials have vastly different properties than
others?
(3) It is interesting and helps to make you a more informed
person
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Chapter 1: Introduction
• Materials Science consists of four components:
• By manipulating these components, materials can be designed
for human need
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Structure
Performance
Properties
Processing
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Materials Science and Engineering
• Material Science: involves investigating the relationship
between the structure and properties of the material.
• Material Engineering: Is designing or engineering the
structure of a material to produce a predetermined set of
properties (based on the structure-property relationship)
• Structure: is the arrangement of the material’s internal
components, which can be divided several levels
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Structure and Properties
• STRUCTURE: Many levels (or dimensions) of structure
exists in engineering materials
Sub-atomic: Electrons within an individual atom and interaction with the
nuclei
Atomic: Organization of atoms or molecules relative to one another (Cubic,
hexagonal …etc)
Phase level (microscopic): Certain arrangement (or crystal structure) of
atoms prevail throughout certain area of the material which makes it
homogenous in that structure arrangement and properties, it is called
phase.
Macroscopic: (observed by naked eye)
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Structure and Properties
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Level of Structures
Materials are...
engineered structures...not blackboxes!
Structure...has many dimensions...
Structural feature
atomic bonding
missing/extra atoms
crystals (ordered atoms)
second phase particles
crystal texturing
Dimension (m)
< 10 -10
10-10
10 -8 -10-1
10 -8 -10-4
> 10 -6
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• PROPERTIES:
– Properties determine response of material to external stimuli which is able to
provoke different responses
– Properties are independent of Materials shape and size
PROPERTY
STIMULUS or INPUT
EXAMPLES/TYPES
Mechanical
Load or Force
Elastic Modulus
Strength
Electrical
Electric Field
Electrical Conductivity
Dielectric Constant
Thermal
Heat
Heat Capacity
Thermal Conductivity
Magnetic
Magnetic Field
Magnetization
Optical
Electromagnetic or Light
Radiation
Index of Reflection
Deteriorative
Chemical/Electrochemical
Reactions
Index of Refraction
Corrosion Rate
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Structure, Processing, & Properties
• Properties depend on structure
ex: hardness vs structure of steel
Hardness (BHN)
(d)
600
500
400
(c)
(a)
(b)
4m
300
200
30m
30m
100
0.01 0.1
30m
1
10 100 1000
Cooling Rate (C/s)
• Processing can change structure
ex: structure vs cooling rate of steel
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ELECTRICAL
• Electrical Resistivity of Copper:
Adapted from Fig. 18.8, Callister 6e.
(Fig. 18.8 adapted from: J.O. Linde,
Ann Physik 5, 219 (1932); and
C.A. Wert and R.M. Thomson,
Physics of Solids, 2nd edition,
McGraw-Hill Company, New York,
1970.)
• Adding “impurity” atoms to Cu increases resistivity.
• Deforming Cu increases resistivity.
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THERMAL
• Space Shuttle Tiles:
--Silica fiber insulation
offers low heat conduction.
• Thermal Conductivity
of Copper:
Fig. 19.0, Callister 6e.
(Courtesy of Lockheed
Missiles and Space
Company, Inc.)
--It decreases when
you add zinc!
Adapted from
Fig. 19.4W, Callister
6e. (Courtesy of
Lockheed Aerospace
Ceramics Systems,
Sunnyvale, CA)
(Note: "W" denotes
fig. is on CD-ROM.)
Adapted from Fig. 19.4, Callister 6e.
(Fig. 19.4 is adapted from Metals Handbook:
Properties and Selection: Nonferrous alloys
and Pure Metals, Vol. 2, 9th ed., H. Baker,
(Managing Editor), American Society for
Metals, 1979, p. 315.)
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MAGNETIC
• Magnetization
vs. Composition:
--Adding 3 atomic % Si
makes Fe a better
recording medium!
Adapted from C.R. Barrett, W.D. Nix, and
A.S. Tetelman, The Principles of
Engineering Materials, Fig. 1-7(a), p. 9,
1973. Electronically reproduced
by permission of Pearson Education, Inc.,
Upper Saddle River, New Jersey.
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OPTICAL
• Transmittance:
--Aluminum oxide may be transparent, translucent, or
opaque depending on the material structure.
single crystal
polycrystal:
low porosity
polycrystal:
high porosity
Adapted from Fig. 1.2,
Callister 6e.
(Specimen preparation,
P.A. Lessing; photo by J.
Telford.)
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DETERIORATIVE
• Stress & Saltwater...
--causes cracks!
Adapted from Fig. 17.0, Callister 6e.
(Fig. 17.0 is from Marine Corrosion, Causes,
and Prevention, John Wiley and Sons, Inc.,
1975.)
• Heat treatment: slows
crack speed in salt water!
Adapted from Fig. 11.20(b), R.W. Hertzberg, "Deformation and
Fracture Mechanics of Engineering Materials" (4th ed.), p. 505,
John Wiley and Sons, 1996. (Original source: Markus O.
Speidel, Brown Boveri Co.)
--material:
4m
7150-T651 Al "alloy"
(Zn,Cu,Mg,Zr)
Adapted from Fig. 11.24,
Callister 6e. (Fig. 11.24 provided courtesy of G.H.
Narayanan and A.G. Miller, Boeing Commercial
Airplane Company.)
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The Materials Selection Process
1. Pick Application
Determine required Properties
Properties: mechanical, electrical, thermal,
magnetic, optical, deteriorative.
2. Properties
Identify candidate Material(s)
Material: structure, composition.
3. Material
Identify required Processing
Processing: changes structure and overall shape
ex: casting, sintering, forming, joining, annealing.
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Next chapter
Classification of Materials
•
There are FOUR basic classes of materials; based on (a)
Chemical make-up and (b) Atomic Structure; these are:
1.
2.
3.
4.
Metals and Alloys
Ceramics and Glasses
Polymers
Composites
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