Enhanced Mechanical Properties of High Temperature Titanium Alloy Components by Fast Gas Forming with In-Die Quenching

In this paper, Fast Gas Forming with in-die Quenching (FGFQ) of TC31 thin-walled components was developed to integrate gas forming and heat treatment together. This forming process consists of rapid resistance heating, fast gas forming, and in-die quenching. The heating rate and pressurization rate can reach up to 30 ℃/s and 20 MPa/s respectively. The whole forming cycle takes less than one minute, which can significantly improve the forming efficiency. The component possesses the best mechanical properties at the forming temperature of 1040 ℃ and the pressure of 15 MPa. The ultimate tensile strength of the component could reach up to 1292 and 837 MPa respectively at room temperature and 650 ℃, which are improved by 18.2% and 29.8% compared with the initial state. Moreover, the elongation of 11.2% and 16.5% could also remain. The rapid resistance heating and fast gas forming can effectively prevent prior β grains from coarsening during the forming process, which results in the formation of high-density fine martensite and therefore enhance the post-form strength. Also, the refinement of the martensite contributes to the great ductility.