This document provides an introduction to technical materials. It discusses that materials have historically evolved from natural substances like stone and wood to more advanced materials developed through research. Materials can be classified into main categories including metals, polymers, ceramics, composites, and electronics. The properties and performance of a material depend on its structure and processing, and engineers must understand these relationships to select the optimal material for a given application.

1. TECHNICAL MATERIALS
AN INTRODUCTION

2. TECHNICAL MATERIALS
AN INTRODUCTION
Materials can be defined as anything which
satisfies the human needs
or
 Materials are substances of which some thing is
composed or made of.
 Since civilization materials are in use by people
to improve their standard of living.
 Materials are everywhere about us in the
shapes of products
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3. Historical Perspective
 Beginning of the Material Science –
 People began to make tools from stone – Start of the
Stone Age about two million years ago.
 Natural materials: stone, wood, clay, skins, etc.
 The Stone Age ended about 5000 years ago with
introduction of Bronze.
 Bronze is an alloy (copper + tin + other elements).
Bronze: can be hammered or cast into a variety of
shapes, can be made harder by alloying, corrode only
slowly after a surface oxide film forms.
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4. Historical Perspective
 The Iron Age began about 3000 years ago and
continues today.
 Use of iron and steel, a stronger and cheaper material
changed drastically daily life of a common person.
 Age of Advanced materials: throughout the Iron Age
many new types of materials have been introduced
(ceramic, semiconductors, polymers, composites…).
 Understanding of the relationship among structure,
properties, processing, and performance of
materials. Intelligent design of new materials.
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5. Historical Perspective
 A better understanding of
structure-composition
properties relations has lead
to a remarkable progress in
properties of materials.
 Example is the dramatic
progress in the strength to
density ratio of materials, that
resulted in a wide variety of
new products, from dental
materials to tennis racquets.
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6. ENGINEERING MATERIALS-AN
INTRODUCTION
 Commonly encountered materials are wood (timber),
concrete, bricks, steel. plastic, glass, rubber, aluminum,
copper and paper etc.
 If we look around we can easily realize that there are
many more kinds of materials.
 These new types of materials are being frequently
developed as a result of constant research and
development.
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7. The world of materials
Metals,
alloys
Ceramics,
glasses
Polymers,
elastomers
Hybrids,
composites
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8. The world of materials
Polymers,
elastomers
Ceramics,
glasses Hybrids,
composites
Metals,
alloys
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9. Technical materials
 The term technical materials is
specifically used to refer materials to
produce technical products
 However there is no limiting line
between the terms Materials and
Technical materials,
 they can be used interchangeably
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10. Engineers
Technical materials
design
 most of the products and
 their processing systems for the production of
these products.
 Products require materials &
 Engineers should have the knowledge of
engineering materials i.e.
 an engineer should be knowledgeable about the structure
and properties of the materials so that
 he is able to select the most suitable ones for each application
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and he is able to develop best processing methods.

11. Relationship b/w Structural level &
Engineering properties
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12. Relationship b/w Structural
level & Engineering properties
Subatomic level
 Electronic structure of
individual atoms that defines
interaction among atoms
(interatomic bonding).
Atomic level
 Arrangement of atoms in
materials (for the same atoms
can have different properties,
e.g. two forms of carbon:
graphite and diamond)
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13. Relationship b/w Structural
level & Engineering properties
Microscopic structure
 Arrangement of small
grains of material that
can be identified by
microscopy.
Macroscopic structure
 Structural elements that
may be viewed with the
naked eye.
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14. Structure-Property-Processing-Performance
Relationship
 Engineering activities depend upon the selection
of engineering materials whose properties match
the requirements of the application
 Primitive cultures were often limited to the
naturally occurring materials (stone wood, clay) in
their environment.
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15. Structure-Property-Processing-Performance
Relationship
 As civilization developed, the spectrum
of engineering materials expanded.
 Materials could be processed and their
properties altered and possibly
enhanced.
 The alloying and heat treatment of
metals can change the properties of a
material.
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16. Structure-Property-Processing-Performance
Relationship
 While earlier successes in altering materials were
largely the result of trial and error,
 But now
 we recognize that the properties and performance
of a material are the direct result of its structure
and processing
 If we want to change the properties, we will have to
induce changes in the material structure
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17. Classification of Technical materials
Most of the Technical materials can be
classified into main five categories as under:
1. Metallic materials
2. Polymeric materials
3. Ceramic materials
4. Composite materials
5. Electronic materials
6. Advanced materials
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18. cont…… Classification
 Metals
 Steel, Cast Iron,
Aluminum,
Copper, Titanium,
many others
 Ceramics
 Glass, Concrete,
Brick, Alumina,
Zirconia.
 Polymers
 Plastics, Wood,
Cotton (rayon,
nylon), “glue”
 Composites
 Glass Fiber-reinforced
polymers,
 Carbon Fiber-reinforced
polymers,
 Metal Matrix
Composites, e 12/12/14 WEC tc. 18

19. Metallic materials
 These are inorganic substances which are
composed of one or more metallic elements.
 Examples of metallic elements are Iron, Copper,
Aluminum.
 Non-metallic elements such as Carbon,
Nitrogen and Oxygen may also be contained in
the metallic materials.
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20. Metallic materials
 Metals: valence electrons are detached from atoms,
and spread in an 'electron sea' that "glues" the ions
together.
 Crystalline structure
 Strong, ductile
 high thermal & electrical conductivity
 reflective. shiny if polished
 Can be plastically deformed on the application of
load
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21. Metallic materials
 Metallic materials are further classified into
ferrous, and non-ferrous materials.
 Ferrous materials contain large percentage
of iron such as steels and cast irons and
 Non-ferrous materials that do not contain
iron or only relatively small amount of iron.
Example of non-ferrous metals are Al, Cu,
Zn, Ti, & Ni.
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22. Several uses of steel and pressed
aluminum.
Metals
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23. Polymeric materials
 The word polymer is actually taken from two
Greek words, Poly = many and
 mer = repeating units or parts.
 Polymeric materials are usually long organic
molecular chains i. e., compounds of C & H.
 So the polymeric materials are organic
compounds having many repeated units, e.g.,
Teflon, Nylon 6,6, Polythene etc.
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24. Polymeric materials
 Polymers/plastics:
 Covalent bonding  sharing of e’s
 Soft, ductile, low strength, low density
 thermal & electrical insulators
 Optically translucent or transparent.
 cheap
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25. Polymers
Polymers include “Plastics” and rubber materials
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26. Ceramic materials
 The word ceramics actually is taken from the Greek word
“ Keramos “ = burnt stuff / Clay.
 Ceramics are inorganic materials consisting of metallic &
non-metallic elements (oxides, carbides, nitrides, sulfides)
chemically bonded together unlike metallic materials.
 They may be crystalline, non-crystalline or mixtures, e.g.,
glass, refractories.
 Hard, Brittle, glassy, elastic
 non-conducting (insulators)
 Difficult to process, low fracture toughness
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27. Ceramics
Examples of ceramic materials ranging from household to high performance
combustion engines which utilize both metals and ceramics.
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28. Composite materials
 Composite materials are mixtures of two or more
materials to produce properties that are not produced
in a single material, e.g., Fiber glass, concrete,
plywood etc.
 The useful properties which can be produced in such
materials are strength, stiffness, hardness,
temperature resistance, corrosion resistance,
conductivity etc.
 High cost
 Delamination, etc
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29. Composites
Polymer composite materials: reinforcing glass
fibers in a polymer matrix.
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30. Electronic materials
 Semiconductors: the bonding is covalent (electrons
are shared between atoms).
 Their electrical properties depend strongly on
minute proportions of contaminants. Examples: Si,
Ge, GaAs
 Electronic materials are used in electronics, especially
microelectronics, e.g., Silicon, Germanium & Gallium
Arsenide etc.
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31. Si wafer for computer chip
devices.
Semiconductors
Micro-Electrical-Mechanical
Systems (MEMS)
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32. Types of Materials- summary
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33. 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, machining, sintering, vapor deposition, doping
forming, joining, annealing.
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34. Material selection: Properties/performance and cost
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35. But:
Properties depend on Structure
(strength or hardness)
Hardness (BHN)
(c)
4 mm
(b)
30 mm
Cooling Rate (ºC/s)
600
500
400
300
200
100
(d)
30 mm
(a)
30 mm
0.01 0.1 1 10 100 1000
And: Processing can change structure! (see
above structure vs Cooling Rate)
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36. Properties
Properties are the way the material responds to the
environment and external forces.
Mechanical properties – response to mechanical
forces, strength, etc.
Electrical and magnetic properties - response
electrical and magnetic fields, conductivity, etc.
Thermal properties are related to transmission of heat
and heat capacity.
Optical properties include to absorption, transmission
and scattering of light.
Chemical stability in contact with the environment -
corrosion 12/12/14 resistance.
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42. Future of materials science
Design of materials having specific desired characteristics
directly from our knowledge of atomic structure.
• Miniaturization: “Nanostructured" materials, with
microstructure that has length scales between 1 and 100
nanometers with unusual properties.
•Electronic components, materials for quantum computing.
• Smart materials: airplane wings that adjust to the air flow
conditions, buildings that stabilize themselves in earthquakes…
•
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43. Future of materials science
•Environment-friendly materials: biodegradable or
photodegradable plastics, advances in nuclear waste
processing, etc.
• Learning from Nature: shells and biological hard tissue can
be as strong as the most advanced laboratory-produced
ceramics,
• Materials
• for lightweight batteries with high storage densities,
• for turbine blades that can operate at 2500°C,
• room-temperature superconductors?
• chemical sensors (artificial nose) of extremely high
sensitivity,
• cotton shirts that never require ironing…
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44. Advanced Materials
 Materials used in "High-Tec" applications,
usually designed for maximum performance,
and normally expensive. Examples are:
 titanium alloys for supersonic airplanes,
 magnetic alloys for computer disks,
 special ceramics for the heat shield of the space
shuttle, etc.
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45. Advanced Materials
 Modern Material's Needs
 Engine efficiency increases at high temperatures: requires high
temperature structural materials
 Use of nuclear energy requires solving problem with residues,
or advances in nuclear waste processing.
 Hypersonic flight requires materials that are light, strong and
resist high temperatures.
 Optical communications require optical fibers that absorb light
negligibly.
 Civil construction – materials for unbreakable windows.
 Structures: materials that are strong like metals and resist
corrosion like plastics.
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46. Thanks