Phase Transformation And Heat Treatment

OBJECTIVES: To understand the physical metallurgy concepts involved in phase transformations and strengthening mechanisms. 










Introduction and classification of phase transformations. Diffusion in solids: phenomenological approach and atomistic approach. Nucleation and growth theories of vapour to liquid, liquid to solid, and solid to solid transformations; homogeneous and heterogeneous strain energy effect during nucleation; interface-controlled growth and diffusion controlled growth; overall transformation kinetics.


Principles of solidification, evolution of microstructures in pure metals and alloys. Precipitation from solid solution: types of precipitation reactions, crystallographic description of precipitates, precipitation sequence and age hardening, spinoidal decomposition.


Iron-carbon alloy system: iron-carbon diagram, nucleation and growth of pearlite, cooling of hypo-eutectoid, eutectoid, and hyper-eutectoid steels, development of microstructures in cast irons. Heat treatment of steels: TTT and CCT diagrams, bainitic transformation, martensitic transformation, hardenability, role of alloying elements in steels


Conventional heat treatment of steels. Massive transformation. Order-disorder transformation. Phase transformations in and heat treatment of some common non-ferrous metals and alloys  


Types of furnaces and furnace atmospheres; quenching  media;  types of quenching,  mechanism  of  quenching, quenching  characteristics, choice  of quenchants; surface hardening of steels- carburizing, nitriding, carbonitriding and others.. Various thermo-mechanical treatments; Designing for heat treatment, defects in heat treated parts, causes for the defects in heat-treated parts and remedies 




1      Raghavan V., ‘Physical Metallurgy- Principles and Practical’, Prentice Hall,  1983

  1. Rajan T. V.   ‘Heat Treatment - Principles and Practice’, 2nd Edition, Prentice Hall of India, 1996



1.     Avner S.H., ‘Introduction to Physical Metallurgy’, 2nd edition, Tata  McGraw Hill, 1984

2.     Lakhtin Y., ‘Engineering Physical Metallurgy’, 2nd   Edition, MIR Publishers, 1979

  1. Prabhu Dev K. H., ‘Handbook of Heat Treatment of Steel’, TMH,  1988