Resistance heating superplastic forming and influence of current on deformation mechanism of TA15 titanium alloy

摘要

The resistance heating is adopted in bulging process of TA15 titanium alloy to improve the heating efficiency and reduce the energy consumption. The experiments of TA15 titanium alloy resistance heating tension and bulging are performed to investigate the influence of current on titanium alloy hot deformation. Compared with conventional hot deformation, the current will lead to strain concentration due to resistance changing when the necking appears. The TA15 titanium alloy resistance heating superplastic bulging can be carried out with a current density of 7 A/mm(2) and the current can improve the forming property of material. The results show that the dynamic recrystallization takes place during hot bulging process. In deformation process, a part of a phase transforms into beta phase that makes the grains grow up and the beta phase changes into the basket weave structure in the subsequent cooling process. Under the action of current, the grain orientation of deformation titanium alloy shows directivity and the dislocation line is approximately in parallel with others with little tangle and screw that can strengthen the ability of the dislocation glide and enhance the deformation ability of TA15 titanium alloy. The resistance heating forming parts are obtained.