TC18合金动态力学行为的研究与分析

采用电子万能试验机对TC18合金进行了常温准静态压缩实验,得到合金在准静态下的实验数据,根据实验数据,选用分离式Hopkinson压杆对TC18合金在温度分别为298K、523K、773K和1023K,应变率分别为500s_-1、1000s_-1和1500s_-1下进行动态力学性能实验,得到了合金在高温动态压缩条件下的应力-应变曲线,分析了温度和应变率对TC18合金动态力学行为的影响。结果表明：在同一温度下,随着应变速率的增加,TC18合金的塑性应变明显增大,表现出一定的应变率增塑效应；在同一应变率下,随着温度的增加,材料的流变应力有显著的下降,表现出明显的热软化效应；在高应变率下的塑性变形过程中,应变率强化和热软化作用同时进行,当温度超过773K时,热软化作用大于应变率强化作用。

Study and Analysis on Dynamic Mechanical Behavior of TC18 Alloy

A quasi-static compression experiment was performed on the TC18 alloy using an electronic universal testing machine to obtain experimental data of the alloy under quasi-static condition. According to the data, the dynamic mechanical properties of TC18 alloy at 298K, 523K, 773K and 1023K with strain rates of 500s-1, 1000s-1 and 1500s-1 were tested using a split Hopkinson pressure bar. The stress-strain curves of the alloy under dynamic compression at high temperature were obtained. And effects of temperature and strain rate on the dynamic mechanical behavior of TC18 alloy were analyzed. The results showed that plastic strain of TC18 alloy increased obviously with the increase of strain rate at the same temperature, a certain strain-rate plasticizing effect was shown. The flow stress of TC18 alloy decreased significantly with the increase of temperature under the same strain rate, and the obvious thermal softening effect was shown. The strain rate strengthening effect and thermal softening effect were carried out simultaneously in the process of plastic deformation at high strain rate. And the thermal softening effect was greater than strain-rate strengthening effect when the temperature exceeds 773K.