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

Volume and grain boundary diffusivities of 51 Cr and 59 Fe 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.