The growth behavior of Ni3Al phase layer in the β/γ diffusion couple of Ni-Al binary system, including the shape evolution and growth kinetics, were simulated by using the KKS multiphase field model. The simulation results indicated that, when Ni3Al layer growth was completely controlled by volume diffusion, it could be regarded as parabolic growth. However, if fast grain boundary diffusion was taken into account, the growth rate of Ni3Al phase was accelerated, and the growth kinetics deviated from parabolic growth, which was consistent with experiments and other simulation results. The simulation results also demonstrated some details of shape evolution of grains, such as the uneven Ni3Al/γ and Ni 3Al/β interfaces and the grain boundary migration of Ni3Al grains caused by fast grain boundary diffusion.

Phase Field Modeling the Growth of Ni3Al Layer in the β/γ Diffusion Couple of Ni-Al Binary System. Tang, S., Wang, J., Yang, G., Zhou, Y.: Intermetallics, 2011, 19[3], 229-33