片状组织TA15钛合金动态球化行为

利用热模拟试验机对片状TA15钛合金进行等温恒应变速率压缩试验,研究了应变速率为10-3～1 s-1、真应变为0.22～0.92、变形温度为900 ℃和950 ℃时片状组织的动态球化行为.结果表明,真应变对动态球化有较大影响,真应变从0.22增加到0.92时,α相的球化率最大增幅为40%;900 ℃和950 ℃变形时α相的球化率差别不大;当应变速率为10-3～10-1 s-1时,降低应变速率能够显著提高片状α相的球化率,但当应变速率大于10-1 s-1后,球化率随应变速率的变化并不明显.TA15钛合金的真应力-真应变曲线均呈"应变软化"型,这种软化行为主要是由片状α相的动态球化和弯折引起的.

Dynamic Globularization Behavior of TA15 Titanium Alloy with Lamellar Alpha Microstructure

Dynamic globularization behavior of lamellar structure in the TA15 alloy was examined by isothermal constant strain rate compression testing on thermal simulator with strain rate of 10~(-3)～1 s~(-1) and true strain of 0.22～0.92 at 900 and at 950℃. The results reveal that with increasing true strain from 0.22 to 0.92, the globularization rate of alpha phase is increased by 40%, showing obvious effects of true strain on dynamic globularization. At a given true strain and strain rates, globularization rate of alpha phase exhibits slight difference with deformation at 900℃ and at 950℃ , keeping in range of -7% ～7%. When strain rate is in range of 10~(-3) ～10~(-1) s~(-1), with decreasing in strain rate, globularization rate of lamellar alpha phase is greatly improved, while strain rate is more than 10~(-1) s~(-1), globularization rate is nearly independent of the change of strain rate. True strain-true stress curves of TA15 alloy are characterized by flow softening at different strain rates and temperatures, which is attributed to the dynamic globularization and kinking of lamellar alpha phase.