Download - ME -254 MATERIALS ENGINEERING - KSU
Chapter 1 -
ME -254
MATERIALS ENGINEERING
Dr. Md Irfanul Haque Siddiqui (Irfan)
Department of Mechanical Engineering
King Saud University, Riyadh, Saudi Arabia
Email: [email protected]
Office: 2C-69, Building 3
College of Engineering
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Chapter 1 -
MSE XXX: Introduction to
Materials Science & EngineeringCourse Objective...
Introduce fundamental concepts in Materials
Science & Engineering
You will learn about:• material structures
• 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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Chapter 1 -
Required text:• Materials Science and Engineering:
An Introduction, W.D. Callister, Jr. and D.G.
Rethwisch, 9th edition, John Wiley and Sons, Inc.
COURSE MATERIALS (with text)
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Chapter 1 -
Course Website: https://fac.ksu.edu.sa/msiddiqui2c• Syllabus
• Lecture notes
WEBSITES
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Chapter 1 -
GRADING
Midterm #1 XX%Tentatively scheduled for: Week 6th, Thursday 6/7 PM
Material covered:
Midterm #2 XX%Tentatively scheduled for: Week 12th, Thursday 6/7 PM
Material covered:
Final XX%Tentatively scheduled for:
Material covered:
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Chapter 1 -
Chapter 1: Introduction to
Materials Science & Engineering
ISSUES TO ADDRESS...
• What is materials science and engineering?
• Why are materials important?
• Why is it important for engineers to understand
materials ?
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Chapter 1 -
What is Materials Science & Engineering?
• Materials science– Investigate relationships between structures and
properties of materials
– Design/develop new materials
• Materials engineering– Create products from existing materials
– Develop materials processing techniques
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Chapter 1 -
Why Are Materials Important?
• Materials drive advancements in our society – Stone Age
– Bronze Age
– Iron Age
• What is today’s material age?– Silicon (Electronic Materials) Age?
– Nanomaterials Age?
– Polymer Age?
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Chapter 1 -
Why is it Important for Engineers to
Understand Materials?
• Products/devices/components that engineers design are all made of materials
• To select appropriate materials and processing techniques for specific applications engineers must– have knowledge of material properties and
– understand the structure-property relationships
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Chapter 1 -
• Processing (e.g., cooling rate of steel from high
temperature) affects structure (microstructure)
Data obtained from Figs. 10.32(a) and
10.33 with 0.4 wt% C composition, and
from Fig. 11.18, Callister & Rethwisch 10e.
Micrographs adapted from (a) Fig. 10.19;
(b) Fig. 9.30; (c) Fig. 10.34; and (d) Fig.
10.22, Callister & Rethwisch 10e. (Figures
10.19, 10.22, & 10.34 copyright 1971 by United
States Steel Corporation. Figure 9.30 courtesy
of Republic Steel Corporation.)
Relationships Among Processing,
Structure, & Properties
Ha
rdn
ess (
BH
N)
Cooling Rate (ºC/s)
100
200
300
400
500
600
0.01 0.1 1 10 100 1000
(d)
30 μm(c)
4 μm
(b)
30 μm
(a)
30 μm
• Structure in turn effects hardness
Property
Processing
Structure
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Chapter 1 -
Types of Materials• Metals:
– Strong, ductile
– High thermal & electrical conductivities
– Opaque, reflective
• Polymers/plastics: compounds of non-metallic elements
– Soft, ductile, low strengths, low densities
– Low thermal & electrical conductivities
– Opaque, translucent or transparent
• Ceramics: compounds of metallic & non-metallic elements (oxides, carbides, nitrides, sulfides)
– Hard, Brittle
– Low thermal & electrical conductivities
– Opaque, translucent, or transparent
Composites/ Semi-conductors/ biomaterials/ smart materials/ nanomaterials
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Chapter 1 -
1. For a Specific Application Determine Required Properties
• To provide required set of properties
• To produce component having desired shape and size
• Example techniques: casting, mechanical forming, welding,
heat treating
• Properties: mechanical, electrical, thermal,
magnetic, optical, deteriorative.
2. From List of Properties Identify Candidate Material(s)
3. Best Candidate Material Specify Processing technique(s)
Materials Selection
Engineers often solve materials selection problems.
Procedure:
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Chapter 1 -
Material Property Types
• Mechanical
• Electrical
• Thermal
Properties of materials fall into six categories as
follows:
• Magnetic
• Optical
• Deteriorative
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Chapter 1 -
Mechanical Properties
Fig. 10.31, Callister & Rethwisch 10e. [Data taken from Metals Handbook: Heat
Treating, Vol. 4, 9th edition, V. Masseria
(Managing Editor), 1981. Reproduced by
permission of ASM International, Materials Park,
OH.]
80
160
240
320
wt%C0 0.5 1
Brinell
hard
ness
Affect of carbon content on the hardness of a
common steel:
• Increasing carbon content increases hardness of steel.
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Chapter 1 -
Electrical Properties
Factors that affect electrical resistivity – for copper:
• Increasing impurity content (e.g., Ni) increases resistivity.
• Deformation increases resistivity.
Fig. 18.8, Callister & Rethwisch 9e. [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.]
T (°C)-200 -100 0
1
2
3
4
5
6
Resis
tivity,
ρ
(10
-8O
hm
-m)
0
• Increasing temperature increases resistivity.
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Chapter 1 -
Thermal Conductivity – measure of a material’s ability to
conduct heat
Thermal Properties
Composition (wt% Zinc)
Therm
al C
onductivity
(W/m
-K)
400
300
200
100
00 10 20 30 40
• Increasing impurity content (e.g., Zn in Cu) decreases
thermal conductivity.
Fig. 19.4, Callister & Rethwisch 10e. [Adapted from Metals Handbook: Properties
and Selection: Nonferrous alloys and Pure
Metals, Vol. 2, 9th ed., H. Baker, (Managing
Editor), ASM International, 1979, p. 315.]
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Chapter 1 -
Thermal Properties (continued)
Highly porous materials are
poor conductors of heat
Court
esy o
f Lockheed A
ero
space C
era
mic
s
Syste
ms, S
unnyvale
, CA
100μm Court
esy o
f Lockheed M
issiles a
nd S
pace
Com
pany, In
c.
• Ceramic Fibers:– significant void space
– low thermal conductivity
Material used for space
shuttle
• Demonstration:– low thermal conductivity
of this material
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Chapter 1 -
Magnetic Properties• Magnetic Permeability
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.)
Fig. 20.23, Callister & Rethwisch 10e.(Courtesy of HGST, a Western Digital Company.)
• Magnetic Storage:-- Recording medium is
magnetized by recording
write head.
Magnetic Field
Magnetizatio
n
Fe+3%Si
Fe
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Chapter 1 -
• The light transmittance of some materials depend on their
structural characteristics:(S
pecim
en p
repara
tion, P
.A. Lessin
g)
Optical Properties
Aluminum oxide single
crystal (high degree of
perfection)—is optically
transparent
Aluminum oxide
polycrystalline material
(having many small
grains)—is optically
translucent
Aluminum oxide
polycrystalline
material having some
porosity—is optically
opaque
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Chapter 1 -
Deteriorative Properties
• Small cracks formed in steel bar that was simultaneously
stressed and immersed in sea water
- Form of stress-corrosion cracking
Fig. 17.21, Callister & Rethwisch 10e. (from Marine Corrosion, Causes, and Prevention, John Wiley and Sons, Inc., 1975.)
Cracks
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Chapter 1 -
Deteriorative Properties (cont.)
• For stress-corrosion cracking, rate of crack growth is
diminished by heat treating
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.)“heat treated”
Cra
ck G
row
th R
ate
(m
/s) “as-received”
load
10-10
10-8
For Aluminum alloy 7178 that is stressed while immersed in a
saturated aqueous NaCl solution, crack growth rate is reduced by
heat treating (160C for 1 h prior to testing). 21
Chapter 1 -
Example of Materials Selection:
Artificial Hip Replacement
• Anatomy of a
human hip joint and
adjacent skeletal
features
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Chapter 1 -
Materials: Artificial Hip Replacement
(cont.)
Hip joint problems can be painful and disabling
• Joint deterioration (loss of cartilage) as one ages
• Joint fracture
X-ray of normal hip joint X-ray of fractured hip joint
arrows point to
ends of fracture line
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Chapter 1 -
Materials: Artificial Hip Replacement
(cont.)
• Damaged and diseased hip joints can be
replaced with artificial ones
• Materials requirements for artificial joints
– Biocompatible – minimum rejection by surrounding
body tissues
– Chemically inert to body fluids
– Mechanical strength to support forces generated
– Good lubricity and high wear resistance between
articulating surfaces
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Chapter 1 -
Materials: Artificial Hip Replacement
(cont.)
• Materials used- Femoral stem — titanium or CoCrMo alloy
- Head (Ball) — CoCrMo alloy or Al2O3 (ceramic)
- Shell — titanium alloy
- Liner — polyethylene (polymer) or Al2O3 (ceramic)
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Chapter 1 -
SUMMARY
• Appropriate materials and processing decisions
require engineers to understand materials and their
properties.
• Materials' properties depend on their structures;
structures are determined by how materials are
processed
• In terms of chemistry the three classifications of
materials are metals, ceramics, and polymers
• Most properties of materials fall into the following six
categories: mechanical, electrical, thermal, magnetic,
optical, and deteriorative.
• An important role of engineers is that of materials
selection.
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