Forming stability of an Al–Ti–Mo intermetallic compound and its dependence on microstructure

An Al–Ti–Mo experimental alloy was studied by compression tests at high homologous temperatures and different generalized strain rates. The material was processed to obtain two different starting microstructures, coarse and fine grained. The values of the experimental high-temperature deformation data T, ε̇, s (temperature, strain rate and stress, respectively) were analyzed by means of a newly developed algorithm. The different mechanisms controlling the creep process were identified. These mechanisms strongly depend on the microstructure present in the material. Garofalo’s relations for describing the material behavior of each starting microstructure were obtained. The materials constants that were determined for both equations are coherent. The apparent activation energy is slightly higher for the fine-grained material. On the other hand, a different stress exponent for each equation was related with a different mechanisms controlling the deformation process. Finally, a study of the material stability depending on the forming conditions was preformed. Stability zones were specified as a function of the starting microstructure.