Table of Contents

Introduction to Engineering Material and Types Of Engineering Materials

General Definition of Material :

According to Webster’s dictionary, materials are defined as ‘substances of which something is composed or made’

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)

Classification Of Materials :

It is the systematic arrangement or division of materials into groups on the basis of some common characteristic

1. According to General Properties

2. According to Nature of Materials

3. According to Applications

1. According to General Properties

(a). Metals (e.g. iron, aluminium, copper, zinc, lead, etc) Iron as the base metal.

(i). Ferrous: High alloy steel (< 50 % alloying elements), e.g. cast iron, wrought iron, steel, alloys like high-speed steel, spring steel, etc

(ii). Non-Ferrous: 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)

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)

(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

3. According to Applications

(a). Electrical 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). Optical Materials: e.g. glass, quartz, etc

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

Chart shows classification of engineering material

Factors Affecting Material Selection

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, strain rate effect, vibration resistance, wear.• Thermal: e.g. thermal conductivity, expansion coefficient, Resistivity, thermal shock resistance, thermal diffusivity.• Electrical: 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.

2. Constraints
• Design Requirements
• Existing Facilities
• Availability
• Compatibility
• Marketability
• Manufacturability (Fabricability / Castability / Formability / Machinability / Weldability)
• Cost (Material + Fabrication / Manufacturing)