introduction to engg materials
- 1. 1 Module 1 Introduction to Engineering Materials Dr. S. Singh, Dean, SME, KIIT University
- 2. Introduction Stone Age: Naturally accessible materials, i.e. stone, wood, bone, fur Gold was the 1st metal used by the mankind followed by copper Bronze Age: Copper and its alloy like bronze Iron Age: Iron (sponge iron & later pig iron) 1960’s Engineering Materials Metals Design Choice of Material New Materials New Products Number of Materials 40 – 80,000! General Definition of Material According to Webster’s dictionary, materials are defined as ‘substances of which something is composed or made’ Dr. S. Singh, Dean, SME, KIIT University 2
- 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: Material science is the basic knowledge end of materials knowledge spectrum, where as, material engineering is applied knowledge end and there is no demarcation line between the two subjects of interest Dr. S. Singh, Dean, SME, KIIT University 3
- 4. Evolution of Engineering Materials Dr. S. Singh, Dean, SME, KIIT University 4
- 5. 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 wear resistance 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 Dr. S. Singh, Dean, SME, KIIT University 5
- 6. Classification 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 Dr. S. Singh, Dean, SME, KIIT University 6
- 7. 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 (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) Dr. S. Singh, Dean, SME, KIIT University 7
- 8. 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) Dr. S. Singh, Dean, SME, KIIT University 8
- 9. (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 Dr. S. Singh, Dean, SME, KIIT University 9
- 10. 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 Dr. S. Singh, Dean, SME, KIIT University 10
- 11. Engineering Materials Dr. S. Singh, Dean, SME, KIIT University 11 Ceramics Alumina Diamond Magnesia Silicon Carbide Zirconia Composites Carbon Fiber Ceramic Matrix Glass Fiber Metal Matrix Electronic Materials Silicon Germanium Photonic Materials Solid-State Lasers LEDs Bio- Materials Man-Made Proteins Artificial Bacterium Biosensors Advanced / Smart Materials Shape-Memory Alloys Piezoelectric Ceramics Magnetostrictive Materials Optical Fibres Electrorheological Fluids Nanomaterials Metals Ferrous Cast Iron Carbon Steels Alloy Steels Stainless Steels Non- Ferrous Aluminium Brass Bronze Copper Lead Magnesium Nickel Tin Zinc Titanium Polymers Thermoplastic Thermosetting Elastomers ABS Acrylic Nylon Polyethylene Polystyrene Vinyl Epoxy Phenolic Polyester Butyl Fluorocarbon Neoprene Rubber Silicone Classification of Engineering Materials
- 12. Difference between Metals & Non-Metals Property Metals Non-Metals Structure Crystalline Amorphic State Generally solids at room Dr. S. Singh, Dean, SME, KIIT University 12 temp. Gaseous & solid at ordinary temp. Luster Metallic luster No metallic luster (except iodine & graphite) Conductivity Good conductors of heat & electricity Bad conductors Malleability Malleable Not malleable Ductility Ductile Not ductile Hardness Generally hard Hardness varies Electrolysis Form anions Form anioins Excitation of Easy Difficult valence electron by e.m.f. Density High Low
- 13. 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 Dr. S. Singh, Dean, SME, KIIT University 13 Decision making
- 14. Factors Affecting Material Selection 1. Material Performance (depend upon material properties): Adequate properties for anticipated operating conditions / performance 2. Constraints : Design, Availability, Cost etc Dr. S. Singh, Dean, SME, KIIT University 14
- 15. 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 Dr. S. Singh, Dean, SME, KIIT University 15
- 16. Types of Force / Stress System Dr. S. Singh, Dean, SME, KIIT University 16
- 17. • 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 Dr. S. Singh, Dean, SME, KIIT University 17
- 18. 2. Constraints •Design Requirements •Existing Facilities •Availability •Compatibility •Marketability •Manufacturability (Fabricability / Castability / Formability / Machinability / Weldability) •Cost (Material + Fabrication / Manufacturing) Dr. S. Singh, Dean, SME, KIIT University 18
- 19. 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 Dr. S. Singh, Dean, SME, KIIT University 19
- 20. Investigating relationship between Structure & Properties Materials Engineering Designing the structure to achieve the specific properties of the materials Dr. S. Singh, Dean, SME, KIIT University 20 Materials Science Investigating the relationship between structure and properties of the materials Processing Structure Properties Performance
- 21. 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 Dr. S. Singh, Dean, SME, KIIT University 21