Superplasticity of fine grained γ-TiAl based alloy synthesized by pulse current auxiliary sintering

Up to now, most TiAl alloys sintered from coarse particles via resistance sintering have been with coarse fully lamellar microstructures and not promising tensile properties. For the purpose of obtaining γ-TiAl based alloys with ideal mechanical properties, synthesis of coarse pre-alloyed powders was carried out on a self-built similar apparatus named pulse current auxiliary sintering. A dense micron-grained γ-TiAl based alloy was successfully synthesized with superplastic characteristics at over 900 °C in air. The maximum elongation obtained is 437%. The maximum m value reaches 0.8 and the mechanism for superplastic deformation in the alloy under study is determined as the grain boundary sliding accommodated by grain boundary diffusion.