Multi-step circulation heat treatment method for improving mechanical performance of traditional cast gamma-TiAl alloy

The invention relates to a multi-step circulation heat treatment method for improving the mechanical performance of traditional cast gamma-TiAl alloy in order to solve the problems of a rough room temperature structure and poor plasticity of the cast gamma-TiAl alloy. The multi-step circulation heat treatment method comprises the steps of preparation of alloy, hot isostatic pressing treatment, homogenizing treatment, alpha2/gamma phase spheroidizing cycle heat treatment, equiaxed heat treatment and near-lamellar/full-lamellar heat treatment. According to the multi-step circulation heat treatment method, the structure development process is well controlled, a rough lamellar structure is converted into a fine equiaxed structure, and the room temperature performance of the gamma-TiAl alloy is effectively improved. According to the alloy treated through the method, the ductility is 1.9-2.3%, the yield strength is 430-450 Mpa, the breaking strength is 540-570 Mpa, and the aerospace application standards of the TiAl alloy are completely met.