Diffusivities and atomic mobilities for fcc Cu–Ni–Sn alloys

Abstract

Utilizing five groups of bulk diffusion couples together with electron probe microanalysis technique, the composition-dependent ternary interdiffusion coefficients in fcc Cu–Ni–Sn alloys at 1023K were determined via the Whittle and Green method. The presently obtained interdiffusion coefficients at 1023K as well as our previously measured ones at 1073K were combined with the slightly modified thermodynamic descriptions of the fcc Cu–Ni–Sn phase to explore atomic mobilities of Cu, Ni and Sn in fcc Cu–Ni–Sn alloys within the CALPHAD framework. In order to be consistent with the thermodynamic description, atomic mobilities in binary fcc Ni–Sn alloys were re-evaluated in the present work. The quality of the assessed kinetic characteristics was confirmed by the comprehensive comparisons between various model-predicted diffusion behaviors and the experimental ones, including concentration profiles and diffusion paths.