High temperature deformation of a submicron grained Al-12 wt% Ti alloy

Compressive deformation behavior of a MA Al-12wt%Ti alloy has been studied at 623–773 K with strain rates from 4 × 10⁻⁵ to 1 × 10⁻¹s⁻¹. A high stress exponent was observed in the stress dependence of strain rate. By assuming that the presence of a threshold stress is the cause of the high stress exponent, the experimental data were analyzed and compared with existing models. The creep behavior of this alloy is found similar to the dispersion strengthened Al-Al₂O₃ alloys. It is suggested that the high temperature deformation of this alloy is mainly governed by the fine carbide and oxide strengthened aluminum matrix, which can be described by lattice-diffusion controlled creep with a “constant structure” 11]. In addition, a strong temperature dependence of the threshold stress was observed. It might be related to certain grain boundary processes and/or thermally activated deformation of strengthening particles.