Diffusion simulation based on atomistic model and mobility determination via Kirkendall experiment for multi-component systems

Currently the multi-component diffusion kinetic databases, one of the key inputs for successful predictions of microstructural evolution, are by no means reliable since they are developed mostly by only seeking interdiffusion properties via diffusion-couple experiments but without considering the indispensable tracer or intrinsic diffusion coefficients. Estimating interdiffusion coefficients becomes challenging with the increasing number of components. In the present work, a mobility-extraction method is presented to directly determine atomic mobilities, which is in turn used to develop kinetic databases and then calculate all sorts of diffusion coefficients. It requires only one single-phase diffusion couple with Kirkendall markers to obtain the atomic mobilities in the marker position, with no limit on the number of components. This novel idea is realized on the basis of a new simulation scheme to solve diffusion equations in line with the atomistic model, which takes the Kirkendall effect into account intrinsically and efficiently.