Interdiffusion in B2 Type Intermetallic Compound FeAl under High Pressures

Abstract

Interdiffusion coefficient in the B2 FeAl phase at 46–50 at%Al has been measured in the temperature range from 1173 to 1473K under the pressure from 0.1MPa to 5GPa. The activation volume for interdiffusion, ~ V , derived from the pressure dependence of interdiffusion coefficient is found to be 0.58–0.90Vm (Vm: molar volume of alloys), which is comparable to or larger than 0.4–0.6Vm for the monovacancy mechanism in bcc pure metals or random alloys. The value of ~ V increases with increasing temperature and also with deviating from stoichiometry, suggesting that divacancy contributes to the diffusion in higher temperatures and in the region of off-stoichiometry.