Atomistic Simulations of Interface-Controlled Phase Transformations

摘要

A multi-lattice kinetic Monte Carlo method has been used for an atomistic study on moving interfaces in interface-controlled phase transformations. Depending on the driving force of the transformation a continuous or a plane-by-plane lateral growth mode occurs. In case of plane-by-plane growth 2-dimensional nucleation is required to accomplish the transformation. To study the activation energy of the interface mobility for an fcc to bcc massive transformation in a single element system, lateral growth mode simulations have been performed. Series of unfavourable atomic jumps control the transformation rate because atoms on the fcc lattice in general cannot jump directly to bcc lattice sites since neighbouring atoms block the empty bcc sites. The magnitude of the difference between the mobility activation energy and the activation energy for diffusion is determined by the interface structure.