This document provides an introduction to engineering materials. It discusses the importance of studying engineering materials and outlines the course outcomes. The key classes of materials covered include ionic crystals, covalent materials, metals and alloys, semiconductors, superconductors, polymers, composite materials, and ceramics. Examples are provided for each class and their properties and applications are summarized. Catalysts are also introduced. The document concludes by outlining some of the mechanical, thermal, electrical, magnetic, optical and chemical properties of engineering materials.

1. INTRODUCTION TO
ENGINEERING MATERIALS
BY GANESH
KULKARNI

2. Why should WE study Engineering
Materials?
The world is in the middle of a
materials revolution.
Materials science and engineering has
transformed every aspect of modern
living.
 Advances in engineered materials are
crucial to the continued vitality of

3. COURSE OUTCOMES
o Describe the role of engineering materials in the design
of systems and their selection strategy.
o Apply the knowledge of crystal structure and
deformation behaviour to select appropriate material.
o Discuss how engineering materials respond to applied
mechanical loads in both a macroscopic and
microscopic sense at ambient temperature and high
temperature applications.

4. Evolution of engineering materials

6. CLASSES OF MATERIALS
Ionic crystals
Covalent materials
Metal & alloys
Semiconductors
Superconductors
Polymers
Composite materials
Ceramics
Inorganic glasses
Catalysts

7. IONIC CRYSTALS
Ionic Bond is Formed by transfer of
electrons
Example: NaCl,KCl,MgCl2 etc
Properties of Ionic Crystals
1.Solid Crystals have high melting
point.
2.They Conduct electricity in molten
state.
3.Low thermal conductivity.
4.Soluble in polar solvents.

8. APPLICATION OF IONIC
CRYSTALS
Nacl is used for cooking purpose which make
food tasty.
 Preservation of cheese, dairy products, meat,
pickles and sauces.
 Cacl2 salt is used as Road salt to remove
snow fallen on road in Cold countries. It
lowers the freezing point water.
 Potassium chloride produced is used for
making fertilizer

9. COVALENT
MATERIALS
Covalent bond formed by the sharing of
electrons
Example: Diamond, Graphite, Fullerene
etc
DIAMOND
• Highest hardness and thermal
conductivity of any bulk material.
• A diamond is a transparent crystal of
tetrahedral bonded carbon
atoms(sp3)
• Diamond lattice face centered cubic
structure

10. GRAPHITE
 Graphite has a layered, planar structure with
hexagonal lattice of Carbon atoms (SP2).
 Graphite powder with clay mixed in as a
binding agent are used in synthesis of
pencil.
FULLURENE
 Fullerene is molecule composed entirely of
carbon, in the form of a hollow sphere.
 Carbon is sp2 hybridization.
 Fullerenes consist of 20 hexagonal and 12
pentagonal rings
 Fullerenes are currently applied in cosmetics
and sports goods industries.
 Fullerenes are also used in slow drug

11. METAL AND ALLOYS
• Metallic bonding is the
bonding between atoms
within metals.
• Alloy is homogenous
mixture of two or more
elements
Example: copper, aluminium,
brass, stainless steel etc.
Properties of metals and
alloys
1. High tensile strength.

12. APPLICATION OF METALS AND
ALLOYS
Due to their electric properties they are
used in electric wire and electrical
devices.
Stainless steel alloy is milled into coils,
sheets, plates, bars, wire and turbing to be
used in cookware, hardware, surgical
instruments.
Brass can be used for the
metallic coatings of several
lock, Watch etc.

13. SEMICONDUCTORS
 The bonding is covalent (electrons are shared
between atoms). Their electrical properties depend
strongly on minute proportions of dopants.
Examples: Si,Ge etc
Dopants:
Boron (3rd group element)
Phosphorus (5th group element)
Properties of semiconductors
1. They are crystalline properties lie In-between
insulator and conductors.
2. Their conductivity varies with temperature.

14. Application of semiconductors
Semiconductor memory uses semiconductor-
based integrated circuits to store information
Si wafer in photovoltaic cells to convert
light energy to electric energy.
A transistor is a semiconductor device
used to amplify and switch electronic
signals

15. SUPERCONDUCTORS
An element , intermetallic alloy or
compound that will conduct electricity
without resistance below certain
Temperature.
Example: Pb(-265.83˚C)etc
Properties of superconductors
1. Meissner effect: Superconductors are
diamagnetic compounds which repel
magnetic field.
2. Josephson effect: When 2
superconductors sheets are separated
by small thin insulating material the

16. APPLICATION OF
SUPERCONDUCTORS
Based on Meissner effect trains can be made to “float” on strong
superconducting magnets, virtually eliminating friction between
the train and its tracks.
Speed: 581 Kph in shanghai.

17. SYTNHETIC POLYMERS
Polymer: Hgih molecular weight molecule made up of a small repeat
unit(monomer).
Example : polyster, nylon Bakelite etc.
Types of polymers:
1. Thermoplastics: can be processed by melting (several cycles of
heating and cooling are possible for thermally stabilized polymers)
Example:PVC,PET etc
2. Thermosets: cannot be melted or dissolved to be processed
:Chemical decomposition occurs before softening.
Example: Vulcanized rubber Bakelite.

18. APPLICATION OF SYNTHETIC
POLYMER
Polypropylene the polymer we are using from morning to night

19. COMPOSITE MATERIALS
Two inherently different maerials that when combined together produce a
material with properties that exceed the constituent materials.
Composites materials consist of two main materials.
Reinforcement(Strong load carrying material) EX: carbon,fiberglass
Tensile Properties
Stiffness
Impact Resistance
Matrix (imbedded weaker material)EX: polypropylene, polyvinyl chloride
etc.
Transfer Load to Reinforcement
Temperature Resisitance
Chemical Resisitance

20. APPLICATION OF COMPOSITE
MATERIALS
Carbon fiber composites with polymer
matrices,have become the advanced composite
materials for aerospace, due to their high
strength,high Modulus and low cost.
Helmet and bullet proof
jacket made up of
Aramide Composite
material
Fiber-reinforced plastics have reached the stage
where they could be used for making wheels.

21. CERAMICS
Ceramic is an inorganic, nonmetallic
solid prepared by the action of heat
and subsequent cooling.
Example:clay,Mixed oxides like
alumina Zirconia etc.
Properties Of Ceramics
1. Ceramics are strong solid inert
materials.
2. They withstand chemical erosion
due to acid and caustic.
3. These can withstand high
temperature of about 1000C to
1600C.

22. CATALYST
Catalyst is substance which alters the rate of reaction without
itself undergoing any chemical change in the reaction
Acid catalyzed reaction usually catalyzed by acids
Ex: H2SO4,Hcl,Alcl3,HF,BF3etc
Solid Acid catalyst
Zeolites
Heteropolyacids
Sulfated zirconia
Mixed oxides

23. MECHANICAL
PROPERTIES

24. THERMAL PROPERTIES

25. ELECTRICAL, MAGNETIC AND OPTICAL
PROPERTIES

26. CHEMICAL
PROPERTIES