Experimental and computational study of interdiffusion for fcc Ni-Cu-Cr alloys

The interdiffusion behavior of fcc Ni-Cu-Cr alloys has been studied by experiments and computational methods. The concentration profiles of binary fcc Ni-Cu diffusion couples annealed at 1123 and 1273 K and those of ternary fcc Ni-Cu-Cr diffusion couples annealed at 1173, 1273 and 1373 K have been measured by using electron probe microanalysis (EPMA). Then the interdiffusion coefficients were determined using the Sauer-Freise and Whittle-Green method based on the measured concentration profiles of binary and ternary diffusion couples, respectively. Based on the diffusion coefficients reported in the literature and those determined in the present work, the atomic mobilities for fcc Ni-Cu-Cr alloys have been assessed. To validate the present assessed mobilities, various diffusion coefficients (i.e., impurity, tracer and intrinsic diffusion coefficients), concentration profiles and diffusion paths of fcc Ni-Cu-Cr alloys were calculated and compared with the experimental data. Good agreements and predictions were obtained.