Computational simulation of voids formation and evolution in Kirkendall effect

An important phenomenon of Kirkendall effect is the presence of voids that formed during diffusion, which may crack the mechanical properties. In this paper, a cellular automaton (CA) based model is developed to simulate the voids formation and evolution process of Kirkendall effect. Firstly, this paper derives the critical radius of voids nucleation and the nucleation rate. Secondly, this paper derives the growth rate of Kirkendall voids, and the relationship between the movement of interface plane and the growth rate of voids. According to the formulas derived from this paper, the number of voids and the average radius of voids can be inferred by observing the shift velocity of interface plane between the different metals. Theoretical analysis is helpful for the fundamental understanding of the underlying mechanisms of Kirkendall voids, and is helpful for the study on suppressing the formation of Kirkendall voids. Thirdly, this paper presents a numerical simulation on Kirkendall voids formation and evolution process based on cellular automaton, which provides an intuitive visual process of Kirkendall voids growth and the movement of interface plane.