DE ZG 631 Materials Technology and
Testing
Lecture 01(Introduction).
BITS Pilani
Pilani Campus
Prof.P.Srinivasan.
Mechanical Engineering Department
Details of Presentation
Introduction to Materials Science
and Engineering.
Types of Engineering materials,
properties and Applications.
Advanced Materials.
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BITS Pilani, Pilani Campus
Materials Science and Engineering
Materials Science
-The discipline of investigating the relationships that exist between the structures
and properties of materials.
Materials Engineering
– The discipline of designing or engineering the structure of a material to produce a
predetermined set of properties based on established structure-property
correlation.
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Historical Evolution of Materials
Ages of “Man” we survive based on the materials we control
– Stone Age – naturally occurring materials
• Special rocks, skins, wood
– Bronze Age
• Casting and forging
– Iron Age
• High Temperature furnaces
– Steel Age
• High Strength Alloys
– Non-Ferrous and Polymer Age
• Aluminum, Titanium and Nickel (superalloys) – aerospace
• Silicon – Information
• Plastics and Composites – food preservation, housing, aerospace
and higher speeds
– Exotic Materials Age?
• Nano-Material and bio-Materials – they are coming and then …
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Basic Engineering Materials
Metals:
– Strong, ductile
– high thermal & electrical conductivity
– opaque, reflective.
Polymers/plastics: Covalent bonding  sharing of e’s
– Soft, ductile, low strength, low density
– thermal & electrical insulators
– Optically translucent or transparent.
Ceramics: ionic bonding (refractory) – compounds of metallic & nonmetallic elements (oxides, carbides, nitrides, sulfides)
– Brittle, glassy, elastic
– non-conducting (insulators)
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BITS Pilani, Pilani Campus
BITS Pilani, Pilani Campus
BITS Pilani, Pilani Campus
Examples of Metallic Materials.
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Examples of Ceramic
Materials.
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Examples of Polymeric
Materials.
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About structure of materials
It relates to the arrangement of its internal components.
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



Subatomic Structure
Atomic Structure
Crystal structure
Microscopic Structure
Macroscopic Structure
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Structure of materials and influence
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Four Major Components of Material Science
and Engineering:
– Structure of Materials
– Properties of Materials
– Processing of Materials
– Performance of Materials
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Structure, Processing, & Properties
• Properties depend on structure
ex: hardness vs structure of steel
Hardness (BHN)
(d)
600
500
400
(a)
(b)
4m
300
200
30m
(c)
30m
100
0.01 0.1
30m
Data obtained from Figs. 10.21(a)
and 10.23 with 4wt%C composition,
and from Fig. 11.13 and associated
discussion, Callister 6e.
Micrographs adapted from (a) Fig.
10.10; (b) Fig. 9.27;(c) Fig. 10.24;
and (d) Fig. 10.12, Callister 6e.
1
10 100 1000
Cooling Rate (C/s)
• Processing can change structure
ex: structure vs cooling rate of steel
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Materials of the Future
Smart Materials
– Able to sense the changes in their environment and respond to these
changes in predetermined manner. Following materials used for actuators.
– Shape Memory Alloy
– Piezoelectric Ceramics
– Magnetostrictive Materials
– Electro-rheological/ Magnetorheological Fluids
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Continued..
Nanotechnology
Top down approach
Bottom up approach
The study of properties of materials using
bottom up approach is called Nanotechnology.
“Nano” refers to the dimensions of the structural
entities are on order of a nanometer (10-9m) as a rule
less than 100 nanometers.
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BITS Pilani, Pilani Campus
Transportation
Reducing the weight of the transportation vehicle.
Increasing the Engine operation Condition.
New High strength, low density material remain to be
developed.
Materials that have high temperature capabilities, for use in
engine components.
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Continued..
To find new and economical source of energy and to use
present resource more efficiently.
Materials play significant role in these developments e.g.:
Solar Cells.
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Maintaining the Environmental Quality
Depends upon our ability to control air and water
pollution.
Need to improve the material processing and
refinements so that they produce less
environmental degradation.
In some materials manufacturing process, toxic
substances are produced and ecological impact
of their disposal must be considered.
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Continued..
Materials derived from Nonrenewable resources.
 Includes Polymers (made from oil and some metals)
 These nonrenewable resources are gradually depleting which necessitates
 Discovery of additional reservoirs.
 Development of new and comparable material
 Increased recycling efforts and development of
new recycling technology.
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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, vapor deposition, doping
forming, joining, annealing.
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Six Important Properties
Mechanical
Electrical
Thermal
Magnetic
Optical
Deteriorative.
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ELECTRICAL
• Electrical Resistivity of Copper:
6
From Fig. 17.8
Callister’s Materials Science and Engineering
Adapted Version.
(Fig. 17.8 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.)
(10-8 Ohm-m)
Resistivity, r
5
4
3
2
1
0
-200
-100
0
T (°C)
• Adding “impurity” atoms to Cu increases resistivity.
• Deforming Cu increases resistivity.
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THERMAL
--Silica fiber insulation
offers low heat conduction.
From chapter-opening
photograph, Chapter 19,
Callister’s Materials Science
and Engineering,
Adapted Version.
(Courtesy of Lockheed
Missiles and Space
Company, Inc.)
• Thermal Conductivity
of Copper:
--It decreases when
you add zinc!
Thermal Conductivity
(W/m-K)
• Space Shuttle Tiles:
Adapted from
Fig. 19.4W, Callister 6e.
(Courtesy of Lockheed
Aerospace Ceramics
Systems, Sunnyvale, CA)
(Note: "W" denotes fig.
is on CD-ROM.)
400
300
200
100
0
0
10
20 30 40
Composition (wt% Zinc)
From Fig. 19.4
Callister’s Materials Science and Engineering,
Adapted Version.
(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.)
100m
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MAGNETIC
• Magnetic Storage:
Magnetic Permeability
vs. Composition:
--Adding 3 atomic % Si
makes Fe a better
recording medium!
Magnetization
--Recording medium
is magnetized by
recording head.
•
Fe+3%Si
Fe
Magnetic Field
Fig. 18.23
Callister’s Materials Science and Engineering,
Adapted Version.
(Fig. 18.23 is from J.U. Lemke, MRS Bulletin,
Vol. XV, No. 3, p. 31, 1990.)
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’s Materials Science
and Engineering,
Adapted Version.
(Specimen preparation,
P.A. Lessing; photo by S.
Tanner.)
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DETERIORATIVE
• Stress & Saltwater...
crack speed (m/s)
--causes cracks!
slows
crack speed in salt water!
• Heat treatment:
10 -8
“as-is”
“held at
160ºC for 1 hr
before testing”
10 -10
From chapter-opening photograph, Chapter 16
Callister’s Materials Science and Engineering,
Adapted Version.
(from Marine Corrosion, Causes, and Prevention,
John Wiley and Sons, Inc., 1975.)
Alloy 7178 tested in
saturated aqueous NaCl
solution at 23ºC
increasing load
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)
From Fig. 10.31,
Callister’s Materials Science and Engineering,
Adapted Version.
(Fig. 10.31 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, vapor deposition, doping
forming, joining, annealing.
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SUMMARY
Course Goals:
• Use the right material for the job.
• Understand the relation between properties,
structure, and processing.
• Recognize new design opportunities offered
by materials selection.
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