Tensile behaviors of fine-grained γ-TiAl based alloys synthesized by pulse current auxiliary sintering

Micro-grained γ-TiAl based alloy obtained via pulse current auxiliary sintering exhibits good room temperature ductility with the common influence of fine grain size and inner twinning microstructure. Superplastic behavior at relatively low temperatures is also observed. It is also noted that the tensile strength of the studied alloy manifests anomalous hardening from room temperature to approximately 600 °C as a result of the controlling of dislocations slip, and softening above 600 °C due to thermal activation. Based on calculation, the superplastic deformation mechanism in the present work is determined as the grain boundary sliding accommodated by grain boundary diffusion.