TA15钛合金超塑变形量对变形后力学性能的影响

Effect of superplastic deformation magnitude on mechanical properties of TA15 titanium alloy

采用在920、初始应变速率为1.0×10-3 s-1和1.67×10-3 s-1的条件下对TA15钛合金进行超塑拉伸,在超塑变形后的试样标距里截取后续拉伸试样,分析超塑变形量对TA15钛合金在室温和500的力学性能影响规律,以及对金相组织变化的影响。试验结果表明,在延伸率不大的情况下（≤100%）,超塑变形对TA15钛合金在室温和500的力学性能的影响相对较小;当延伸率高于220%,变形后TA15钛合金的强度性能下降5~10个百分点,而延伸率由于晶粒尺寸的增大而大幅下降50个百分点或更多。

The superplastic tension tests of TA15 titanium alloy with initial strain rates of 1.0 × 10-3 s-1 and 1.67 × 10-3 s-1 were performed at 920 ℃. Subsequent tensile specimens were cut from the gauge of superplastically stretched specimens. The effect of superplastic deformation magnitude on mechanical properties of TA15 titanium alloy at room tempera- ture and 500 ℃ was studied. The optical microstructure was also discussed. The experimen- tal results show the superplastic deformation has a minor effect on mechanical properties of TA15 titanium alloy at room temperature and 500 ℃ when pre-elongation is less than 100%. When pre-clongation is more than 220%, the strength of TA15 titanium alloy decreases by 5-10% after deformation while the elongation significantly reduces by 50% and more due to the increase of grain size.