Comparison of Tensile Deformation Behavior of TA15 Alloy at Constant Strain Rate with High-Low Temperature

In order to further study the superplastic deformation behavior of titanium alloys, the tensile tests of TA15 alloy at constant strain rate were carried out with temperature ranging from 700 to 900 ℃,and strain rate changing from 1×10⁻² to 1×10⁻⁴ s⁻¹. The deformation behaviors were compared at different deformation temperatures and strain rates. The results show that the elongation of TA15 alloy rangs from 73.3% to 250.0% when the size of initial equiaxed α phase is 15 μm on average. The highest elongation is achieved at 850 ℃ and 1×10⁻⁴ s⁻¹. In the low temperature range of 700 to 750 ℃, the alloy demonstrates a higher peak stress. At 750 ℃, 1×10⁻⁴ s⁻¹ deformation, the elongation of TA15 alloy is 183.3%. Steady rheological stage of TA15 alloy only appears at high temperature and low strain rate. The longer the duration of this stage, the higher the elongation of the alloy. The microstructure after various deformation have grown up in different degrees, and the microstructure of the sample after deformation at high temperature and low strain rate has the most obvious coarsening.