Assessment of the diffusional mobilities in fcc Ni–Nb and fcc Ni–Mo alloys

The atomic mobilities of the fcc Ni–Nb and Ni–Mo binary system have been assessed on the basis of the available kinetic information and given as functions of temperatures and composition in the CALPHAD format using the DICTRA software package in this work. Good agreement between the calculated and reported experimental diffusion coefficients is obtained. By using optimized mobility parameters, the concentration profiles of the diffusion zone in the binary Ni–Nb and Ni–Mo diffusion couples can be predicted. The assessed atomic mobility parameters are an important part of the construction of mobility database in Ni based alloys, and are also useful in designing high-temperature Ni-based alloy.