MS2084: Phase Transformations and Kinetics in Steels

Course Instructor

Associate Professor Aravind Dasari

Course AIMS

The fundamental understanding of phase transformations in materials is the key for tuning their structure and properties. This course will provide the necessary basic knowledge to relate bonding, diffusion, and temperature (heat treatment) in solids, particularly steel , to their evolution of structure/phase and properties . That is, it presents the connections between thermodynamic concepts, phase transformations and materials properties.  More specifically,  the students will have the opportunity to experience the fundamental concepts lectured in class through experimental work and analyzing/reflecting on the obtained data, and ultimately connecting with the concepts.

The students after listening to the content will work in the lab in groups on different carbon steel samples. They are expected to polish, etch, and understand the grain and microstructure along with their impact and hardness properties before subjecting to different heat treatment conditions. The students will be austenizing the samples and cool them using different cooling rates to achieve desired effect on properties.

Intended Learning Outcomes

By the end of this course, you (as a student) would be able to:

1. Identify carbon sites (interstitial positions – octahedral and tetrahedral) in both ferrite and austenite iron lattices; and illustrate the ir importance in terms of strength and hardness of the system.
2. Demonstrate the use of Time -Temperature Transformation (TTT) diagrams.
3. Describe the effects of changing process parameters on the microstructure of steels.
4. Explain the mechanisms of phase transformations in steels (based on diffusion and diffusionless transformations).
5. Describe martensitic and pearlitic transformations.
6. Explain the importance and types of cast iron, effects of cooling rate on the microstructure of cast iron, and significance of carbon equivalent.
   

Course Content

1. Introduction to phase transformations and kinetics
2. TTT charts  and the different types of transformations
3. Diffusionless transformations
4. Diffusion -based transformation
5. Cast iron
6. Laboratory – group project
7. Tutorials on the concepts discussed
   

Reading and References

Suggested reading:

• Phase Transformations in Metals and Alloys, 3rd edition, David A Porter, Kenneth E,Easterling, Mohamed Sherif, 2009, CRC Press, ISBN: 978-1-42006-210-6
• Theory of Transformations in Steels, 1st edition, H.K.D.H. Bhadeshia, 2021, CRC Press, ISBN: 978-1-00305-678-2
• Phase Transformations in Steels, Editors: Elena Pereloma and David V. Edmonds, Vol. 2,Woodhead Publishing Series in Metals and Surface Engineering, 2012, ISBN: 978-1-84569-970-3
• Fundamentals of solidification, 4th edition, W. Kurz and D.J. Fisher, 1998, Trans Tech Publications, ISBN: 978-0-87849-804-8
  

Additional reading:

• Materials science and engineering: an introduction, Willian D Callister, Wiley
• Introduction to the thermodynamics of materials, 5th edition by David Gaskell, Yaylor and Francis, 2008