Interdiffusion Coefficients in FCC Co-Rich Co-Ti-V Alloys at 1273, 1373 and 1473 K

Abstract

Based on 18 bulk diffusion couples, the composition-dependent interdiffusion coefficients in the FCC Co-rich Co-Ti-V alloys at 1273, 1373 and 1473 K were obtained from the intersection points of the diffusion couples by means of EPMA technique applied to Whittle and Green method. The reliability of the experimental interdiffusivities is validated via thermodynamic constraints. Taking Co as the solvent element, the present results show that when the temperature is from 1273 to 1473 K, the ternary interdiffusion coefficients increases from 10−16 to 10−14 m2/s and the diffusion of Ti is generally faster than V. The ternary main interdiffusion coefficients of $$\tilde{D}_{\text{TiTi}}^{\text{Co}}$$ and $$\tilde{D}_{\text{VV}}^{\text{Co}}$$ at different compositions of Ti and V at 1473 K were compared with the values obtained for boundary binary Co-Ti and Co-V systems in the literature. A composition-dependent decreasing-increasing tendency was found for $$\tilde{D}_{\text{VV}}^{\text{Co}}$$ .