The effect of carbide formation on the development of the bainitic type transformation was studied using phase field modeling. The phase field model incorporated the displacive structural transformation producing a misfitting product phase, long range elastic interactions, carbon partitioning from austenite and ferrite and the formation of carbides in ferrite modelled as carbon sinks. The results of the simulations performed for the systems with different carbide nucleation sequences demonstrate that initially, due to a slow nucleation of carbides and fast carbon partitioning, carbon diffusion to austenite was the dominant process leading to the decrease in the transformation rate. However, after some period of time, the effect of carbon depletion in the solid solution by carbides became more significant, which led to the reduction of the average concentration of carbon in the whole system and the acceleration of the structural transformation. The rate of carbide nucleation and the number of nucleated carbides controlled both the transformation rate and the period of time before the transformation acceleration.

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Computational Materials Science
Department of Mechanical and Aerospace Engineering

Elhigazi, F. (F.), & Artemev, A. (2021). The influence of carbide formation in ferrite on the bainitic type transformation. Computational Materials Science, 186. doi:10.1016/j.commatsci.2020.109961