Characterization of Kinetics of Deformation-Enhanced Transformation in a Low Carbon Steel
Quantitative characterization of microstructural development during deformation enhanced transformation in a low carbon steel was investigated on a Gleeble 1500 machine. General conclusions of the features of austenite transformation kinetics during deformation-enhanced transformation were formulated. It was shown that the process of deformation-enhanced transformation can be divided into three stages according to the characteristics of transformation kinetics: The kinetics equations of two early stages fitted well in J-M-A equation. The kinetics of the first stage obeys Cahn’s site saturation mechanism, with the value of kinetics parameter n of 4. Ferrite nucleates at austenite grain boundaries and triple points during the first stage. Kinetics of the second stage doesn’t obey Cahn’s theory, with the value of kinetics parameter n of 1-1.5, corresponding to ferrite nucleation repeatedly at areas with high stored energy in front of the ferrite/austenite interface. The kinetics doesn’t obey the law of J-M-A equation any more in the final stage, and only few nucleation sites left at this moment.
Z.Y. Zhong, H. Saka, T.H. Kim, E.A. Holm, Y.F. Han and X.S. Xie
J. J. Qi et al., "Characterization of Kinetics of Deformation-Enhanced Transformation in a Low Carbon Steel", Materials Science Forum, Vols. 475-479, pp. 73-76, 2005