A multi-lattice kinetic Monte Carlo atomistic simulation method was used to simulate the austenite to ferrite interface-controlled transformation in pure Fe. By performing simulations with various amounts of so-called free volume at the interface, quantitative relationships between the activation energies for interface mobility, boundary self diffusion and bulk self diffusion were investigated. The effect of different interface orientations upon the distribution of free volume over the interface, as determined by interface crystallography, and its consequences for interface mobility activation energy was also evaluated. The essential role of thermal fluctuations in free-volume distribution at the interface was shown. The activation enthalpy for boundary diffusion was shown to be larger than the interface mobility activation enthalpy.

Atomistic Study on the Activation Enthalpies for Interface Mobility and Boundary Diffusion in an Interface-Controlled Phase Transformation. C.Bos, F.Sommer, E.J.Mittemeijer: Philosophical Magazine, 2007, 87[16], 2245-62