Please join us for the inaugural lecture of MSE’s Distinguished Lecture Series
Nucleation Theory and the Austenite to Ferrite Transformation in Steels
The formation of the BCC ferrite phase from FCC austenite in steels is perhaps the most well studied example of solid-solid phase transformations, yet a complete understanding of the transformation remains elusive. In this work the nucleation of ferrite at grain boundaries in a polycrystalline system of austenite has been monitored using molecular dynamics simulations in a quasi-2D geometry. The pure Fe system was modeled using an embedded atom interatomic potential. Consistent with experiment we find that the critical nucleus always exhibits a special orientation relationship (OR) with the surrounding austenite matrix and the OR is consistent with either the Kurdjimov-Sachs or Nishiyama-Wasserman type. The critical nucleus size and shape is compared with predictions from classical nucleation theory and adequate agreement is found. Finally, we present evidence that under certain conditions a barrier free nucleation of ferrite is possible.
About the speaker
Professor Jeffrey J. Hoyt
Chair, Materials Science and Engineering Department, McMaster University
Professor Jeffrey Hoyt is the Chair of Materials Science and Engineering department at McMaster University. He is a world-known authority in the computational modeling of phase transformations in metallic systems, with more than 100 journal publications in this field. Professor Hoyt started his teaching career in the Department of Mechanical and Materials Engineering at Washington State University. From ten years starting in 1997, he worked at the Sandia National Laboratories in both Albuquerque, New Mexico and Livermore, CA. In 2007 he joined the MSE department at McMaster University and has served as Chair since 2012.