This document discusses different types of engineering materials. It covers metals, including ferrous and non-ferrous metals. It also discusses non-metals like timber, leather, and rubber. Additionally, it examines polymers, ceramics, composites and applications of thermoplastics and thermosets. Specific materials discussed include steel, aluminum, wood, plastics and epoxy resins. The document provides information on properties and common uses of these important engineering materials.

1. ENGINEERING
MATERIALS
By
Er. Sanjeev singh
Assistant Professor
Civil Engineering Department
Tawi Engineering college Shahpur kandi Pathankot

2. CLASSIFICATION OF
ENGINEERING MATERIALS

3. METALS AND NON-FERROUS METALS
A solid material which is typically hard, shiny, malleable,
fusible, and ductile, with good electrical and thermal
conductivity (e.g. iron, gold, silver, and aluminium, and
alloys such as steel).
Metals may conveniently be divided into ferrous
and non- ferrous metals.
ferrous metals contain iron e.g steel, carbon steel. Etc
Non ferrous matel. Metals containing elements other
than iron as their chief constituents are usually
referred to as non-ferrous metals. There is a wide
variety of non-metals in practice.

4. Non-metals- Non-metallic materials are also used in
engineering practice due to principally their low cost, flexibility
and resistance to heat and electricity. Though there are many
suitable non-metals, the following are important few from design
point of view:
Timber- This is a relatively low cost material and a bad
conductor of heat and electricity. It has also good elastic and
frictional properties and is widely used in foundry patterns and
as water lubricated bearings.
Leather- This is widely used in engineering for its flexibility
and wear resistance. It is widely used for belt drives, washers
and such other applications.
Rubber- It has high bulk modulus and is used for drive
elements, sealing, vibration isolation and similar applications.
Plastics are synthetic materials which can be moulded into
desired shapes under pressure with or without application of
heat. These are now extensively used in various industrial
applications for their corrosion resistance, dimensional stability
and relatively low cost.

5. Thermosetting plastics- Thermosetting plastics are formed
under heat and pressure. It initially softens and with increasing
heat and pressure, polymerization takes place. This results in
hardening of the material. These plastics cannot be deformed or
remolded again under heat and pressure. Some examples of
thermosetting plastics are phenol formaldehyde (Bakelite),
phenol-furfural (Durite), epoxy resins, phenolic resins etc.
Thermoplastics- Thermoplastics do not become hard with the
application of heat and pressure and no chemical change takes
place. They remain soft at elevated temperatures until they are
hardened by cooling. These can be re-melted and remolded by
application of heat and pressure. Some examples of
thermoplastics are cellulose nitrate (celluloid), polythene,
polyvinyl acetate, polyvinyl chloride ( PVC) etc.

6. POLYMERS
Polymers – Chain of H-C molecules. Each repeat unit of H-
C is a monomer e.g. ethylene (C2H4), Polyethylene – (–CH2
– CH2)n
Polymers:
Thermo plasts – Soften when heated and harden on cooling
– totally reversible.
Thermosets – Do not soften on heating
oPlastics – moldable into many shape and have sufficient
structural rigidity. Are one of the most commonly used class
of materials.
oAre used in clothing, housing, automobiles, aircraft,
packaging, electronics, signs, recreation items, and medical
implants.
oNatural plastics – hellac, rubber, asphalt, and cellulose.

7. APPLICATIONS OF SOME COMMON THERMOPLASTICS
Material Characteristics Applications
Polyethylene Chemically resistant, tough, low
friction coefficient, low strength
Flexible bottles, toys, battery
parts, ice trays, film wrapping
materials
Polyamide (Nylon) Good strength and toughness,
abrasion resistant, liquid absorber,
low friction coeff.
Bearings, gears, cams,
bushings and jacketing for
wires and cables
Fluorocarbon
(Teflon)
Chemically inert, excellent electrical
properties, relatively weak
Anticorrosive seals, chemical
pipes and valves, bearings,
anti-adhesive coatings, high
temp electronic parts
Polyester (PET) Tough plastic film, excellent fatigue
and tear strength, corrosion resistant
Recording tapes, clothing,
automotive tyre cords,
beverage containers
Vinyl Low-cost general purpose material,
rigid, can be made flexible
Floor coverings, pipe, electric
al wire insulation, garden
hose, phonograph records
Polystyrene Excellent electrical prop and optical
clarity, good thermal and
dimensional stability
Wall tile, battery cases, toys,
lighting panels, housing
appliances

8. APPLICATIONS OF SOME
COMMON THERMOSETSMaterial Characteristics Applications
Epoxy (Araldite) Excellent mechanical properties and
corrosion resistance, good electrical
prop., good adhesion and dimensional
stability
Electrical
adhesives,
coatings,
moldings, sinks,
protective
fiber reinforced
plastic (FRP), laminates
Phenolic
(Bakelite)
Excellent thermal stability (>150 C),
inexpensive, can be compounded with
many resins
Motor housings, telephones,
auto distributors, electrical
fixtures
Polyester
(Aropol)
Excellent electrical properties, low cost,
can formulated for room or high
temperature, often fiber reinforced
Helmets, fiberglass boats,
auto body components, chair
fans

9. CERAMICS
Ceramics Materials
•Refractory Materials
•Advanced Ceramics
• Abrasives
•Glass Ceramics

10. REFRACTORY MATERIALS
Zirconia - extremely high temperatures.
Sic and Carbon – also used in some very severe
temperature conditions, but cannot be used in oxygen
environment, as they will oxidize and burn.

11. ABRASIVE CERAMICS
o
o
Abrasives are used in cutting and grinding tools.
Diamonds - natural and synthetic, are used as
abrasives, though relatively expensive. Industrial
diamonds are hard and thermally conductive.
Diamonds unsuitable as gemstone are used as
industrial diamond
Either bonded to a grinding wheel or made into a
powder and used with a cloth or paper.
o

12. ADVANCED CERAMICS
Automobile Engine parts Advantages:
Operate at high temperatures – high efficiencies; Low
frictional losses; Operate without a cooling system;
Lower weights than current engines Disadvantages:
Ceramic materials are brittle; Difficult to remove
internal voids (that weaken structures);
Ceramic parts are difficult to form and machine
Potential materials: Si 3 N4 (engine valves, ball
bearings), SiC (MESFETS), & ZrO2 (sensors), Possible
engine parts: engine block & piston coatings

13. REFRACTORY MATERIALS
Refractory - retains its strength at high temperatures >
500°C.
Must be chemically and physically stable at high
temperatures. Need to be resistant to thermal shock,
should be chemically inert, and have specific ranges of
thermal conductivity and thermal expansion.
Are used in linings for furnaces, kilns,incinerators,
crucibles and reactors.
Aluminum oxide (alumina), silicon oxide (silica), calcium
oxide (lime) magnesium oxide (magnesia) and fireclays are
used to manufacture refractory materials.

14. COMPOSITES
A materials system composed of two or more
physically distinct phases whose combination
produces aggregate properties that are different from
those of its constituents
Examples:
Cemented carbides (WC with Co binder)
Plastic molding compounds containing fillers
Rubber mixed with carbon black
Wood (a natural composite as distinguished from a
synthesized composite)

15. WHY COMPOSITES ARE
IMPORTANTComposites can be very strong and stiff, yet very
light in weight, so ratios of strength-to-weight
and stiffness-to-weight are several times greater
than steel or aluminum
Fatigue properties are generally better than for
common engineering metals
Toughness is often greater too
Composites can be designed that do not corrode
like steel
Possible to achieve combinations of properties not
attainable with metals, ceramics, or polymers
alone

16. DISADVANTAGES AND
LIMITATIONS OF
COMPOSITE MATERIALS
Properties of many important composites are
anisotropic - the properties differ depending on the
direction in which they are measured – this may be an
advantage or a disadvantage
Many of the polymer-based composites are subject to
attack by chemicals or solvents, just as the polymers
themselves are susceptible to attack
Composite materials are generally expensive
Manufacturing methods for shaping composite
materials are often slow and costly