TC21钛合金动态拉伸行为的率-热效应及其本构关系  

Effect of Strain Rate and Temperature on the Dynamic Tensile Behavior and Constitutive Model of TC21 Titanium Alloy

作　　者：李云飞[1,2] 曾祥国[1] Li Yunfei;Zeng Xiangguo(Sichuan University, Chengdu 610065, China;China Academy of Engineering Physics, Mianyang 621999, China)

机构地区：[1]四川大学,四川成都610065 [2]中国工程物理研究院,四川绵阳621999

出　　处：《稀有金属材料与工程》2018年第6期1760-1765,共6页Rare Metal Materials and Engineering

基　　金：国家自然科学基金委员会与中国工程物理研究院联合基金(U1430119)

摘　　要：对TC21两相钛合金材料在不同温度下从准静态到高应变率范围(0.001~1200 s^(-1))的动态拉伸力学行为进行了试验研究。通过静态试验机与分离式Hopkinson拉杆装置,获取了TC21钛合金在单轴拉伸载荷下的应力-应变响应曲线。同时通过动态拉伸复元试验方法得到了材料在高应变率下的等温应力-应变响应曲线。由试验结果可见,TC21钛合金的动态拉伸力学行为具备应变率-温度敏感特性,其初始屈服应力随应变率增加而增大,随温度升高而减小,通过引入2个敏感度系数对TC21材料的率-热效应进行了探究。同时根据等温试验数据对Johnson-Cook唯象本构模型进行修正来描述TC21钛合金率-热相关性的本构行为。对比模型预测结果与试验数据,二者吻合良好,验证了修正模型的准确性。The dynamic tensile behavior of a newly developed Ti-6Al-2Sn-2Zr-3Mo-1Cr-2Nb-Si alloy（referred as TC21） over a wide range of strain rates from quasi-static to dynamic regimes（0.001-1200 s-1） at different temperatures were experimentally investigated. Split Hopkinson tension bar apparatus and a static material testing system were employed to obtain the stress-strain response under uniaxial tension loading condition. The results indicate that the tensile behavior of TC21 titanium alloy is dependent on the strain rate and temperature. The initial yield stress increases with the strain rate increasing. The effects of strain rate and temperature on the initial yield behavior were studied by introducing two rate sensitivity parameters. The phenomenologically based constitutive model（Johnson-Cook model） was suitably modified to describe the dynamic tensile behavior of TC21 titanium alloy. The predicted results of the modified model are in good agreement with the experimental data in the investigating range of strain rates and temperatures.

关 键 词：两相钛合金 动态拉伸行为 率-热敏感性 本构模型 

分 类 号：TG146.23[一般工业技术—材料科学与工程] TG113.25[金属学及工艺—金属材料]