module 1, intro to engg materials

8/12/2019 Module 1, Intro to Engg Materials

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Module 1

Introduction to Engineering Materials

Sanjib Jaypuria, SME, KIIT University


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2Sanjib Jaypuria, SME, KIIT University

1960s Engineering Materials Metals

Design Choice of Material

New Materials New Products

Number of Materials 40 80,000!

General Definition of Material

According to Websters dictionary, materials are defined as

substancesof which som eth ing is composed or made

Introduction

Stone Age: Naturally accessible materials, i.e. stone, wood, bone, fur

Gold was the 1s tmetal used by the mankind fo l lowed by copp er

Bronze Age: Copper and its alloy like bronze

Iron Age: Iron (sponge iron & later pig iron)


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Sanjib Jaypuria, SME, KIIT University 3

Engineering Material: Part of inanimate matter, which is useful to

engineer in the practice of his profession (used to produce

products according to the needs and demand of society)

Material Science: Primarily concerned with the search for basic

knowledge about internal structure, properties and processing of

materials and their complex interactions/relationships

Material Engineering: Mainly concerned with the use of

fundamental and applied knowledge of materials, so that they may

be converted into products, as needed or desired by the society

(bridges materials knowledge from basic sciences to engineering

disciplines)

Note:Mater ial scienc e is the basic kn ow ledge end o f mater ials kn ow ledge

spectrum , wh ere as, mater ial engineer ing is appl ied know ledge end and

there is no d emarcat ion l ine between the two sub jects of interest


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Evolution of Engineering Materials


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Why Material Science & Engineering is important to technologists?

Examples:

Mechanical engineers search for high temp material so that gas

turbines, jet engines etc can operate more efficiently and wearresistance materials to manufacture bearing materials

Electrical engineers search for materials by which electrical

devices or machines can be operated at a faster rate with minimum

power losses

Aerospace & automobile engineers search for materials having

high strength-to-weight ratio

Electronic engineers search for material that are useful in the

fabrication & miniaturization of electronic devices

Chemical engineers search for highly corrosion-resistant materials

Note: All these demands may be fulfilled when the internal structure

and engineering properties are known to an engineer or technologist


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Classification

It is the systematic arrangement or division of materials into

groups on the basis of some common characteristic

1. Ac cord ing to General Propert ies

2. Ac cord ing to Nature of Mater ials

3. Ac cord ing to App l icat ions


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1. According to General Properties

(a). Metals (e.g.iron, aluminium, copper, zinc, lead, etc)

Iron as the base metal, and range from plain carbon (> 98 % Fe) to

( i). Ferrous : high alloy steel (< 50 % alloying elements), e.g. cast

iron, wrought iron, steel, alloys like high-speed steel, spring steel,

etc

( i i). Non-Ferrou s: Rest of the all other metals and their alloys, e.g.

copper, aluminium, zinc lead, alloys like brass, bronze, duralumin,

etc

(b). Non-Metals (e.g. leather, rubber, asbestos, plastics, etc)


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2. According to Nature of Materials

(a). Metals: e.g. Iron & Steel, Alloys & Superalloys, Intermetallic

Compounds, etc

(b). Ceramics: e.g. Structural Ceramics (high-temperature load

bearing), Refractories (corrosion-resistant, insulating), Whitewares

(porcelains), Glass, Electrical Ceramics (capacitors, insulators,

transducers), Chemically Bonded Ceramics (cement & concrete)

(c).Polymers: e.g. Plastics, Liquid Crystals, Adhesives

(d). Electronic Materials: e.g. Silicon, Germanium, Photonic

materials (solid-state lasers, LEDs)


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(e). Composites: e.g. Particulate composites (small particles

embedded in a different material), Laminate composites (golf club

shafts, tennis rackets), Fiber reinforced composites (fiberglass)

(f). Biomaterials: e.g. Man-made proteins (artificial bacterium),

Biosensors, etc

(g). Advanced / Smart Materials: e.g. materials in computers

(VCRs, CD Players, etc), fibreoptic systems, spacecrafts,

aircrafts, rockets, shape-memory alloys, piezoelectric ceramics,

magnetostrictive materials, optical fibres,microelectromechanical (MEMs) devices, electrorheological /

magnetorheological fluids, Nanomaterials, etc


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3. According to Applications

(a). Electr ical Materials :e.g. conductors, insulators, dielectrics,

etc

(b). Electronic Materials: e.g. conductors, semi-conductors, etc

(c ). Magnetic Materials : e.g. ferromagnetic, paramagnetic &diamagnetic materials, etc

(d). Opt ical Materials : e.g. glass, quartz, etc

(e). Bio Materials: e.g. man-made proteins, artificial bacterium


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Engineering Materials

Ceramics

Alumina

Diamond

Magnesia

Silicon

Carbide

Zirconia

Composites

Carbon F iber

Ceramic

Matrix

Glass F iber

Metal M atrix

Electronic

Materials

Silicon

Germanium

Photonic

Materials

Solid-State

Lasers

LEDs

Bio-

Materials

Man-Made

Proteins

Artif icial

Bacterium

Biosensors

Advanced /

Smart

Materials

Shape-Memory Al loys

Piezoelectric Cerami cs

Magnetostri ctive Materi als

Optical Fi bres

Electrorheological Fl uids

Nanomaterials

Metals

Ferrous

Non-

Ferrous

Cast Ir on

Carbon Steels

Al loy Steels

Stain less Steels

Aluminium

Brass

Bronze

Copper

Lead

Magnesium

Nickel

TinZinc

Titanium

Polymers

Thermoplastic

Thermosetting

Elastomers

ABS

Acrylic

Nylon

Polyethylene

Polystyrene

Vinyl

Epoxy

Phenolic

Polyester

Butyl

Fluorocarbon

Neoprene

Rubber

Silicone

Classification of Engineering Materials


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Property Metals Non-MetalsStructure Crystalline AmorphicState Generally solids at room

temp. Gaseous & solid at ordinary temp.Luster Metallic luster No metallic luster (except iodine &

graphite)Conductivity Good conductors of heat &

electricityBad conductors

Malleability Malleable Not malleableDuctility Ductile Not ductileHardness Generally hard Hardness variesElectrolysis Form anions Form anioinsExcitation ofvalence electron

by e.m.f.Easy Difficult

Density High Low

Difference between Metals & Non-Metals


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Procedure for Selection of Materials (Engineering Applications)

Analysis of material application problem

Translation of material application requirements to material

property values

Selection of candidate materials

Evaluation of candidate materials

Decision making


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Factors Affecting Material Selection

1. Material Performance (depend upon material properties):

Adequate properties for anticipated operating conditions /

performance

2. Cons traints : Design, Availability, Cost etc


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1. Material Performance

Physical : e.g. appearance, shape, weight, boiling point, melting

point, freezing point, density, glass transition temperature,

permeability

Mechanical: e.g. strength (tensile, compressive, shear, torsion,

bending), elasticity, plasticity, ductility, malleability, rigidity,

toughness, hardness, brittleness, impact, fatigue, creep, strain

hardening, Bauschinger effect, strain rate effect, vibration

resistance, wear

Thermal: e.g. thermal conductivity, expansion coefficient,

resistivity, thermal shock resistance, thermal diffusivity


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Types of Force / Stress System


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Electr ical: e.g. conductivity, resistivity, dielectric strength,

thermoelectricity, superconductivity, electric hysteresis

Magnetic: e.g. ferromagnetism, paramagnetism, diamagnetism,

magnetic permeability, coercive force, curie temperature,

magnetic hysteresis

Chemical: e.g. reactivity, corrosion resistance, polymerization,

composition, acidity, alkalinity

Optical : e.g. reflectivity, refractivity, absorptivity, transparency,

opaqueness, color, luster

Metallurgical: e.g. grain size, heat treatment done / required,

anisotropy, hardenability


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2. Constraints

Design Requirements

Existing Facilities

Availability

Compatibility

Marketability

Manufacturability (Fabricability / Castability / Formability /

Machinability / Weldability)

Cost (Material + Fabrication / Manufacturing)


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Others Factors Affecting Material Performance

Structure-property -Processing Relationships

Hot Work, Cold Work,

Solid Solution Strengthening

Precipitation Hardening

Inclusions

Imperfections (Number of Dislocations)

Crystal structures: Crystalline vs Amorphous

Toughening

Heat treatment (Annealing, Normalizing, Quenching)

Residual Stresses


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Investigating relationship between Structure & Properties

Materials Engineering

Designing the structure

to achieve the specific

properties of the

materials

Materials Science

Investigating the

relationship between

structure and

properties of thematerials

Processing

Structure

Properties

Performance


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Competition among Materials

Factors causing material replacement: Cost (breakthrough in

processing cost) & development of new materials with specific

properties for some specific applications

Usage of material in US automobiles

module 1, intro to engg materials

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