TA15钛合金应力松弛行为研究

Research on stress relaxation behavior of TA15 titanium alloy

对TA15钛合金进行了高温单向拉伸试验,获得了试验用板材在不同温度和应变速率下的力学性能。在此基础上,开展了板材高温应力松弛试验,得到了该材料在600、650、700和750℃这4个典型温度下的应力松弛曲线。研究了温度对TA15钛合金应力松弛行为、松弛应力和松弛应变的影响,获得了应力松弛速率与时间的变化关系。结果表明:温度越高,保温时间越长,试样在卸除外载荷后,松弛应力和松弛应变较小。且温度范围700~750℃,保温时间5~8 min时,回弹消除彻底和高效,为降低回弹的较优工艺参数,研究结果可为热成形工艺、热校形工艺及紧固件的使用周期提供指导。

The high temperature one-way tensile test of TA15 titanium alloy was carried out,and the mechanical properties under different temperatures and strain rates of plate were obtained. Based on this,the high temperature stress relaxation experiment was carried out,and the stress relaxation curves of the material at four typical temperatures of 600,650,700 and 750 ℃ were obtained. The effects of temperatures on stress relaxation behavior,relaxation stress and relaxation strain of TA15 titanium alloy were studied,and the relationship between stress relaxation rate and time was got. The results show that the higher the temperature,the longer the thermal insulation time,the less the relaxation stress and relaxation strain after unloading. The parameters with temperature from 700 to 750 ℃,with heat preservation from 5 to 8 min are the optimal process parameters to eliminate springback thoroughly and efficiently. The results can provide guidance for hot forming,hot shape correction process and the service cycle of fasteners.