Some interesting aspects of displacive transformations in steels скачать в хорошем качестве

Some interesting aspects of displacive transformations in steels

This seminar is by Shiv Brat Singh of the Indian Institute of Technology Kharagpur, organised by Prakash Srirangam. Steels based on bainitic microstructure can potentially be used for a number of applications, some of which will be described in brief to set the scene for the talk. In the simplest terms, bainite can be defined as a non-lamellar aggregate of lath- or plate-shaped ferrite and carbide or untransformed austenite. Bainite usually forms at temperatures that are intermediate between those of reconstructive pearlite and displacive martensite, even though in some cases there may be some overlap and exhibits characteristic features of both pearlite and martensite transformation which make it difficult to understand the mechanism of transformation unambiguously. After a brief introduction to the mechanism of transformation, the talk will focus on two interesting aspects of the transformation. A number of studies, including in our group, have reported bainite transformation below the Ms temperature. Analysis of the kinetics of such transformation will be discussed to throw some light on the mechanism of the transformation. More recent studies on isothermal bainite transformation have shown that the amount of carbon in solid solution in bainitic ferrite could be much higher than expected from considerations of equilibrium between BCC ferrite and austenite. These results would be interpreted in terms of the displacive mechanism of transformation. Finally, an example of how these results can be used to optimize the amount of retained austenite in Quenched and Partitioned steel will be provided. Professor S B Singh is the Head of the Metallurgical Engineering Department as well as the Chairman of Steel Technology Centre at IIT Kharagpur, India. He completed his PhD in Metallurgical Engineering from the University of Cambridge in 1998. His research interests are in physical metallurgy, phase transformations and the thermomechanical processing of steels. His Ph.D. thesis is available from https://www.phase-trans.msm.cam.ac.uk...