Study on Tensile Deformation Behavior of TC21 Titanium Alloy

To investigate the tensile deformation behavior of TC21 titanium alloy wires, the isothermal tensile deformation tests were conducted by a Geeble-1500D simulator in the temperature range of 720-880 °C and strain rates of 0.01-10 s−1. The in situ tensile deformation behavior has been studied by SEM SURPA40. The stress–strain curves indicate that the flow stress has shown an inverse relationship with temperature and a direct relationship with strain rate. The flow stress immediately reached the peak value and, then, gradually decreased due to the dynamic softening induced by dynamic recovery and dynamic recrystallization. According to the hot processing maps, the temperatures ranging from 720 to 760 °C (corresponding to the strain rates of 0.01-0.032 s−1) and 800-840 °C (corresponding to the strain rates of 0.01-0.056 s−1) are suitable for processing. The in situ tensile results reveal that the cracks initiated at the pre-fabricated defects with the concentrated stress and mainly propagated in the transgranular mode.