Research status of advanced forming technology for high performance titanium alloys

At present, according to the working temperature when plastic deformation occurs, metal-plastic deformation can be divided into cold forming (below the recrystallization temperature without recovery process), thermal deformation (above the recrystallization temperature), and warm deformation (between the above two). In the forming process of titanium alloy sheets, hot forming is the most mature and widely used forming technology, mainly including electric furnace heating, resistance heating, and induction heating. Titanium alloy hot forming technology is to heat the titanium alloy sheet to the appropriate forming temperature, and use the plastic deformation softening characteristics of titanium alloy at high temperature (the yield strength decreases and the elongation increases) to realize the forming of complex titanium alloy parts. At present, the research on titanium alloy hot forming mainly focuses on forming equipment, forming process, microstructure, formability, and forming limit.

Since the 1990s, scholars from various countries have carried out a large number of experiments and theoretical studies on the electro plasticity of Al, Ti, Ni, Cu, and other materials, and put forward a series of relevant theories on the electro plasticity effect. Compared with the Joule heat effect of traditional thermal assisted forming, currently assisted forming technology also has a pure electro-plastic effect, skin effect, magnetic compression effect, and so on, that is, the multi-field coupling effect of electric thermal force, which has an impact on the microstructure and mechanical properties of materials. At the same time, the current assisted forming process has the advantages of low equipment complexity, fast heating rate, high electro thermal conversion rate, and high heating uniformity. It has broad development prospects in the field of plastic processing of difficult to form metals at room temperature and is expected to be applied in bending, drawing, rolling, bulging, progressive forming, and other forming processes.