Diffusion of Cr and Fe in a High-Purity Fe-50 mass%Cr-8 mass%W Alloy

Abstract

Volume and grain boundary diffusivities of ⁵¹Cr and ⁵⁹Fe in a high purity Fe–50 mass%Cr–8 mass%W (Fe–50Cr–8W) alloy have been determined in the temperature range between 1023 and 1373 K with the sputter-microsectioning technique. The volume diffusion coefficients of Cr and Fe in the Fe–50Cr–8W alloy are smaller than those in a high-purity Fe–50 mass%Cr (Fe–50Cr) alloy. Linear Arrhenius lines for the volume self-diffusion coefficients of both tracers have been observed in the temperature range examined. The activation energies for the volume diffusion of both components in the Fe–50Cr–8W alloy are somewhat smaller than those in the Fe–50Cr alloy. On the other hand, the grain boundary diffusivities of Cr and Fe in the Fe–50Cr–8W alloy at 1123 K are about two orders of magnitude smaller than those in the Fe–50Cr alloy.