ML3007 Phase Transformations Syllabus:
ML3007 Phase Transformations Syllabus – Anna University Regulation 2021
COURSE OBJECTIVES:
The main learning objective of this course is to prepare the students for:
• Acquiring knowledge on the diffusion mechanisms and the various phase transformations that happen due to diffusion.
• Understanding the significance and importance of phase transformations and its influence on the mechanical behaviour.
• Gaining Knowledge on the diffusion less transformations that occurs in ferrous and non-ferrous materials.
• Understanding the concepts involved in the precipitation processes.
• Getting an insight on the concepts of recovery, grain growth and recrystallisation in detail.
UNIT I DIFFUSION MECHANISMS
Basics of thermodynamic & kinetics: equilibrium – configurational entropy – free energy of mixing – miscibility gap – chemical potential. Diffusion – uphill diffusion – downhill diffusion – atomic mechanisms of diffusion, Fick’s 1st
and 2nd law – solution to the diffusion equation – error functions – application of the non-steady state diffusion, spinodal decomposition
UNIT II DIFFUSION CONTROLLED PHASE TRANSFORMATIONS
Nucleation and growth – types of nucleation – concept of free energy during solidification – thermodynamics and kinetics of homogeneous and heterogenous nucleation – critical nucleus size and critical free energy change – nucleation rate and growth rate – overall transformation rate, concept of activation energy – Arrhenius equation – Johnson-Mehl-Avrami equation, Pearlitic transformations.
UNIT III DIFFUSIONLESS PHASE TRANSFORMATIONS
Martensite transformation – definition – characteristic features of Martensitic transformation in steels – morphology of Martensite – lath and acicular martensite – crystallography of martensitic transformation – martensite in non-ferrous systems – thermoelastic martensite – shape memory effect – examples and applications of shape memory alloys.
UNIT IV PRECIPITATION REACTIONS
Precipitation reaction – thermodynamic considerations, structure and property during ageing– sequence of ageing – formation of G-P zones and intermediate precipitates, theories of precipitation hardening – effect of time, temperature and alloy compositions – precipitation free zones, crystallographic aspects of transformation, coarsening kinetics.
UNIT V RECOVERY, RECRYSTALLISATION AND GRAIN GROWTH
Cold working and hot working, recovery – polygonisation and dislocation movements in polygonisation, recrystallisation – effect of time, temperature, strain and other variables – Mechanism of nucleation and growth, grain growth – grain growth law, geometrical collisions, preferred orientation, secondary recrystallisation.
TOTAL: 45 PERIODS
COURSE OUTCOMES:
Upon Completion of the course the students will be able to:
1. Explain the various diffusion mechanisms and the thermodynamic and kinetic principles.
2. Classify the various diffusion controlled transformations and infer the effect of various parameters on the kinetics and growth of nucleation
3. Compare the differences between the diffusion controlled and diffusionless transformations and explain the diffusionless transformations in steels and non-ferrous alloys.
4. Interpret the thermal cycle on the alloys and the effect of time, temperature and composition during precipitation hardening.
5. Recall the concept of recovery, recrystallization and grain growth in cold worked and hot worked steels.
TEXT BOOKS
1. David A. Porter, Kenneth E. Easterling, Mohamed Y. Sherif, “Phase Transformations in Metals and Alloys”, CRC Press, New York, 3rd edition, 2009.
2. Jena, A.K., and Chaturvedi, M., “Phase Transformations in Materials”, Prentice-Hall, 1993.
REFERENCES
1. Anil Sinha, “Physical Metallurgy Handbook”, McGraw-Hill Professional; 1st edition, 2002.
2. Reed Hill. R. E., “Physical Metallurgy Principles”, Affiliated East West Press, New Delhi, 1992.
3. Romesh C. Sharma, “Phase Transformation in Materials”, CBS Publishers & Distributors, New Delhi, 2002.