Creep strength of a binary Al62Ti38 alloy

Abstract

Al-rich Ti–Al alloys, as compared to Ti-rich γ-TiAl-based alloys, offer an additional reduction in density of 20%, better oxidation resistance and sufficient strength at high temperatures. High temperature creep of a binary Al62Ti28 alloy was studied in compression in the temperature range between 1173 K and 1323 K in air. It is shown that the alloy exhibits quite reasonable creep resistance at 1173 K, especially in view of its low density of around 3.8 g cm–3. Stress exponents calculated as the slope n = Δ log (strain rate)/Δ log (stress) = 4 were found to be relatively constant for the temperature and stress regime investigated. This indicates that dislocation climb may be the rate controlling creep mechanism. The values of the activation energies for creep for the as-cast and the annealed Al62Ti38 material coincides well with those found in the literature for interdiffusion of Al in γ-TiAl.