Effect of rhenium addition on tungsten diffusivity in iron-chromium alloys

The Alloying effect of Re on the diffusivity of W in Fe-15 mol%Cr based alloys was investigated experimentally using the Fe-15Cr/Fe-15Cr-5W and Fe-15Cr-1Re/Fe-15Cr-5W diffusion systems. In these systems, a single ferrite phase existed stably at 1473 K, and Fe and W atoms interdiffused at 1473 K without any attendant changes in the Cr concentration of 15 mol% in them. The measured diffusion length of W atoms was shorter in the Re-containing diffusion system than the Re-free one. Following the binary Boltzmann-Matano method, an apparent interdiffusion coefficient at 1473 K was estimated to be 7.1 X 10(-15) m(2)/S in the Re-free diffusion system and 1.5 x 10-(15) m(2)/S in the Recontaining diffusion system. Thus, the presence of Re in the alloy worked to suppress the atomic diffusion of W in a ferrite phase.