Department of Mechanical Engineering National Institute of Technology Calicut MATERIALS SCIENCE & METALLURGY
MATERIALS SCIENCE AND METALLURGY • IMPORTANCE OF METALS IN INDUSTRY • Eg: table, bench, spectacles, frames, watches, rackets, spikes etc. • INDUSTRY: More dependent- progress in technology calls for constant improvement in properties. • ALLOYS: Combinations of metals- effective use important. • In Engineering applications, their BEHAVIOUR & PROPERTIES to be CONSIDERED
WHAT IS METALLURGY? • ART AND SCIENCE OF PROCURING AND ADAPTING METALS TO SATISFY HUMAN REQUIREMENTS • MOTHER NATURE PROVIDES US WITH EVERYTHING- • METALS WITH NONMETALLIC PARTICLES- TO BE SEPARATED- • THIS FIELD IS EXTRACTIVE METALLURGY • CONVERTED TO USEFUL FORM BY CASTING, ROLLING, etc. TO BILLETS- • THIS FIELD IS MECHANICAL METALLURGY • Control of processes by tests and by application of basic principles- Thermodynamics, Physical Chemistry, Alloying- All these are related.- • PHYSICAL METALLURGY
STUDY OF CRYSTAL STRUCTURES OF METALS AND ALLOYS, THEIR EFFECTS ON PHYSICAL AND MECHANICAL PROPERTIES ETC. • ENGINEER MORE CONCERNED WITH MECHANICAL PROPERTIES AND ENGINEERING DESIGN.
REFRESH- • MATTER (composed of atoms, mechanical strength with forces of attraction between fundamental particles. DALTON’S ATOMIC THEORY (1805)- smallest unit of which matter is composed. • BASIC CHEMICAL CONCEPTS: ATOM, ELEMENT, COMPOUND, MIXTURE, ISOTOPES, PERIODIC TABLE, LIST OF ELEMENTS,BONDING- IONIC, METALLIC, COVALENT, etc; CALCULATION OF BREAKING STRENGTH etc.
Study of Materials Science: • Study of that part of matter which is useful for an engineer in his professional practice.
DIAMOND- • Mainly used by women as ornaments BUT Now, • Used to work as drives in electric cars and other applications. Ultra durable drill bits, semiconductors, optical instruments, etc. • Use of synthetic diamonds for more applications. • Synthetic Diamond Technology (SDT)- By Chemical Vapour Deposition (diamonds made through chemical reaction between gases); High Pressure High Temperature (HPHT) methods Wafer thin to thick made. • SDT not a threat to traditional mined gems (due to preference as ornaments)
MATERIALS: • SOLIDS - Properties:Mainly • (i)Toughness and • (ii)Hardness- (a)Ability to withstand bending or application of shear stresses without fracture (b) Resistance of a surface to abrasion (Brinell, Rockwell, K etc; Impact tests, DTs, NDTs )
PHYSICAL METALLURGY- Knowledge will not make a specialist in all uses of metal, but will provide a foundation for later specialization. A small number of essential ideas form the basis for all the various applications of metals. • Art and Science of metallurgy depend on techniques and principles of other subjects. Most chemical elements are metals.
CRYSTAL STRUCTURE • IMPERFECTIONS- DUE TO HETEROGENOUS NATURE. • EXPERIMENTS- TO DETERMINE PROPERTIES THROUGH STANDARDISED TESTS • ASTM; ASM; ASME; AWS; AMERICAN NATIONAL STANDARDS INSTITUTE (ANSI) • MILITARY SPECIFICATIONS (MIL) • BEHAVIOUR OF METALS- To be studied. • (like Human behaviour- temperament, IQ, Physical tests, Standards and experiments)
SMART MATERIALS- which adjust to the requirements • Also called intelligent materials or active materials • Describes a group of material systems with unique properties. • The field of “smart materials” is not transparent or clearly structured. • Evolved over the past decades with increasing pace during the 1990s
Smart materials, Intelligent Materials, Active Materials, Adaptive Materials and to some extent “actuators” and “sensors” used interchangeably. • Different terms really describe the same effect or property of a material. • Active materials divided into two groups. • The “classical” active materials • as viewed by the academic community and is characterized by the type of response these materials generate. • The second group- materials that respond to stimuli with a change in a key material property, for example electrical conductivity or viscosity
Medicines, • packed items which will indicate the life with change in time, environment, decay etc; • dress materials which will adjust with the human conditions etc. etc.