Research status and prospect in hot forming techniques of TiAl alloys

Lightweight is the eternal theme in the aerospace field. TiAl alloy has a density of 3.9-4.2 g/cm3， which is 1/2 of nickel based superalloy. It has excellent properties of light mass and heat resistance and has important application value in the manufacture of hot-end components of aerospace equipment. However， TiAl alloy has inherent brittleness， low plasticity at room temperature and poor thermal deformation ability， which makes it difficult to process and form， high cost， and limits its large-scale application. Based on the review of the development and application status of TiAl alloy， the research progress of hot forming technology such as casting， powder metallurgy， thermoplastic forming， and additive manufacturing is reviewed. The thermoplastic forming technology， including canned-extrusion， isothermal forging， near-isothermal forging， and canned-rolling， is emphasized. The main problems of the existing plastic forming technology are poor plasticity， high forming difficulty， low forming efficiency， and insufficient performance. In the future， the development direction of plastic forming of TiAl alloy should be high efficiency and low cost near net forming， while improving the utilization rate and mechanical properties of the material.