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ByS.Muthurajan

LecturerDepartment of Mechanical Engineering

Salalah College of Technology

Salalah

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Introduction

Materials science and engineering plays a vital role in this modern age of science

and technology. Various kinds of materials are used in industry, housing,

agriculture, transportation, etc.

Engineering materials used to manufacture of articles or products, dictates whichmanufacturing process or processes are to be used to provide it the desired shape.

The basic knowledge of engineering materials and their properties is of great

significance for a design and manufacturing engineer.

A large numbers of engineering materials exists in the universe such as metals andnon metals (leather, rubber, asbestos, plastic, ceramics, organic polymers,

composites and semi conductor).

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Classification Of Engineering Materials

Metals Ferrous Metal

Non ferrous metal

Polymers Thermoplastics

Thermoset plastics

Elastomers

Ceramics Alumina

Glass

Carbides

Composites Fiber Reinforces plastics

Steel reinforced concrete

Semi conductors

Silicon Germanium

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Metals and alloys

Pure metals possess low strength and do not have the required properties. So,

alloys are produced by melting or sintering two or more metals or metals and a

non-metal, together.

Alloys may consist of two more components. Metals and alloys are further

classified into two major kind namely ferrous metals and non-ferrous metals.

(a) Ferrous metals are those which have the iron as their main constituent,

such as pig iron, cast iron, wrought iron and steels.

(b) Non-ferrous metals are those which have a metal other than iron as

their main constituent, such as copper, aluminium, tin, silver , zinc etc.

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Different types of Materials

Now find what is the material used here to make wire

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Ferrous Metals

Ferrous metals are iron base metals which include all variety of pig iron,

cast iron wrought iron and steels.

The ferrous metals are those which have iron as their main constituents.

The ferrous metals commonly used in engineering practice are cast iron,

wrought iron, steel and alloy steels.

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Main Types of Iron

Cast Iron

White Cast iron

Grey Cast iron

Malleable Cast iron

Ductile Cast iron

Steel

Plain Carbon Steel

Eg : Mild Steel

Alloy Steel

Eg : Stainless Steel

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Cast Iron

Cast iron is basically an alloy of iron and carbon

The carbon content in cast iron varies from 1.7% to 6.67%. It also contains

small amounts of silicon, manganese, phosphorus and sulphur in form of

impurities elements.

Cast iron is very brittle in nature and weak in tension.

It has low cost, good casting characteristics, high compressive strength, high

wear resistance and excellent machinability

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Machine tool structures such as bed, frames, column etc.

Man holes covers.

Rolling mill and general machinery parts.

Cylinder blocks and heads for I.C. engines.

General machinery parts.

Cast Iron

White CI is used to produce malleable iron castings.

For manufacturing those component or parts which require a hard, andabrasion resistant surface such as rim of car.

Railway brake blocks.

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Cast Iron products

http://www.castgrills.com/cast-iron-furniture.html

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Steel

It is an alloy of Iron and Carbon .

Carbon content varies from 0 to 2% .

Mild steel also called as low carbon steel having 0.8% of C

It is ductile in nature.

Stainless steel is an alloy of iron, carbon, chromium, manganese

etc.,

Stainless steel have good corrosion resistance because the presence

of chromium. It is useful for making kitchen vessels.

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Steel products

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Aluminium & its alloys

Aluminium is less in weight

It has good corrosion resistance and strength

It is used in aircraft, electric cable, can for cool drinks etc.,

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Polymers

Polymers consist of carbon chemically combined with usually with hydrogen, oxygen or

other non- metallic substances. They are formed by polymerization reaction in whichsimple molecules are chemically combined into long chain molecules.

Plastics are commonly known as synthetic resins or polymers. In Greek terminology, the

term polymer comprises poly means many and mers means parts.

Examples: Nylon, Teflon, Polyethylene, PVC, Terylene, Cotton etc.

Applications

Polymers are used in making packing's, pipes, covers and insulating materials etc.

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Types of Polymers

Thermoplastics

Those plastics which can be easily softened again and again by heating are called

thermoplastic. Eg:- Polyethylene, Nylon, PVC

Plastic covers, plastic pipes, toys etc.,

Thermosets

Those plastics which are hardened by heat, effecting a non-reversible chemical change,

are called thermo-setting. Eg:- Polyesters, Bakelite

Electric plugs, Furniture material etc.,

Elastomers

Highly elastic in nature. Eg:- Rubber

It is used to make rubber products like tyres, tubes etc.,

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Nylon Rope

Nylon fabric

PVC Pipes

Polyethylene Bags

PET Bottles Electric Switches

Tyre

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Ceramics

Ceramic materials are in organic, non-metallic material made of inorganic compounds

such as oxides, nitrides, borides and carbides.

Theses materials are fabricated by first shaping the powder with or without the

application of pressure into a compact form and after that it is subjected to high

temperature.

Ceramics possesses electrical, magnetic, chemical and thermal properties which are

exceptionally good.

Examples: MgO, SiC, Al2O3, glass, cement, garnets, concrete etc.

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Glasses

It is based on silicon dioxide or silicate.

It is mixed with other oxides of sodium, calcium and boron to improve some

properties.

It is very brittle.

It is used mostly in kitchen appliances.

Glass Silica stone Silica sand

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Domestic ceramics

They are made from Clay

Clay is a naturally occurring aluminium silicate composed primarily of fine-grained

minerals.

It can be mixed with water to get a paste. After giving shape, the water will be dried offand then heated to high temperature.

Aluminium Silicate Aluminium Silicate powder

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Earthenware: Flower pots, house bricks, roof tiles

Vitreous china: Kitchen items, sanitary ware etc.,

Cement : It is made of crystalline particles of CaO, silica and alumina. It becomes very

hard when treated with water.

Wash Basin House Bricks Roof tiles

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Engineering Ceramics

Alumina : High thermal and electrical resistance used as a cutting tool and highquality thermal and electrical insulation

Carbides : Tungsten and Titanium carbides are very hard materials used for

cutting tools

Nitrides : Silicon nitrides and Boron nitrides used in engine parts and cutting

tools

Alumina Grinding wheel Alumina Electrical

insulator

Alumina & Silicon nitride

cutting tools

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Natural Ceramics

It is available in the nature as a result of biological or geological processes

Carbonaceous materials : Chalk, Lime stone and marble

Silicaceous materials : Granite and Basalt

Marbles Granite Basalt Limestone

http://pangea.gr/img/cobblestones/basalt.jpg

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Semi conductors

Semiconductors are solid materials, either non-metallic elements or compounds which

allow electrons to pass through them. These materials occupy intermediate position

between conductors and insulators.

They are neither good conductors or bad conductors.

This is suitable for electronic applications like diodes, transistors, capacitors etc.,

Examples : Silicon and Germanium

Integrated Circuit chip Germanium Diode

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Composite materials

It is made up of two or more materials.

In composites, the base material is called as matrix material.

There are three types of composites :

Polymer matrix composite

Metal matrix composite

Ceramic matrix composite

The other materials are added into this matrix as particles or fibers.

FRP is a composite have the plastic as a base metal and carbon fibers or glass fibers as

sub metal

Examples: Vinyl coated steels, steel reinforced concrete, fiber reinforced

plastics, carbon reinforced rubber etc.

Applications

These materials are used for making aircraft structures, automobile parts, sports items,

structures, and electrical devices.

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Carbon Fiber Reinforce Plastics

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Steel Reinforced Concrete (RCC)

RCC Fencing poles RCC Pipes RCC Slab