Microstructural evolution, hot workability, and mechanical properties of Ti-43Al-2Cr-2Mn-0.2Y alloy.

This study systematically investigated the microstructural evolution, hot workability, and mechanical properties of the β-γ TiAl alloy Ti-43Al-2Cr-2Mn-0.2Y. The as-cast alloy had a wide hot working window and excellent hot workability. A crack-free pancake was obtained through one-step canned forging with an initial deformation condition of 1200 °C/0.1 s- 1. The coarse lamellar microstructures of the as-cast alloy were broken down into fine γ grains after forging. Residual lamellae were hardly observed even near the edge of the pancake. Dynamic recrystallization of γ grains was the main softening mechanism during hot forging. Tensile tests showed that the as-forged alloy exhibited better room temperature tensile properties than the as-cast alloy because of microstructural refinement and homogenization. The ultimate tensile strength of the as-forged alloy at 700 °C was maintained at 496 MPa, and elongation was 10%. The ductile-brittle transition temperature was between 700 and 750 °C. In addition, the nano-hardness values of the β0 and γ phases were 5.6 and 4.6 GPa, respectively. The hardness of the β0 phase was lower than that of the β0 phase in TNM alloys, indicating that the hardness of the β0 phase highly depended on alloying elements. [ABSTRACT FROM AUTHOR]