Grain refining heat treatment method for Ti-44Al-4Nb-4V-0.3Mo alloy

The invention relates to a hot working treatment technology for an titanium-aluminum alloy, in particular to a grain refining heat treatment technology for a Ti-44Al-4Nb-4V-0.3Mo alloy. A grain refining heat treatment method for the Ti-44Al-4Nb-4V-0.3Mo alloy comprises the steps that the Ti-44Al-4Nb-4V-0.3Mo alloy is heated to an alpha+beta two-phase region of a Ti-44Al alloy, isothermal high-temperature deformation is carried out on the Ti-44Al-4Nb-4V-0.3Mo alloy, then air cooling is carried out, and finally heat treatment is carried out on the air-cooled structure so as to obtain the fine and uniform fine-grain structure finally. The method has the advantage that the subsequent machining capability of the titanium-aluminum alloy can be improved.