摘要
通过对分离式Hopkinson拉杆试验装置进行改进,在入射杆与透射杆上加入余波吸收器,消除了动态拉伸过程中反射余波对试件的二次加载,从而发展了动态拉伸复元试验技术。对TC11两相钛合金试件进行动态拉伸复元试验,获得了TC11合金在不同应变率下的等温应力-应变曲线,成功实现了材料的温度软化效应与应变硬化、应变率强化效应的解耦。并且对TC11钛合金开展了不同初始温度下的准静态拉伸试验,采用Johnson-Cook模型描述材料的温度软化效应,并引入绝热动态拉伸过程的绝热温升值对Johnson-Cook模型进行修正,当修正模型计算所得的绝热曲线与试验所得绝热曲线相互吻合时,可以确定TC11钛合金在不同应变率动态拉伸条件下塑性耗散功向热量的转化系数,并且发现了应变率500 s^(-1)下的转化系数要小于应变率190 s^(-1)下的转化系数。
Split Hopkinson tension bar system was improved by adding wave absorbers into the incident bar and the transmission bar, to eliminate the reflected waves in the input and output bar in dynamic tension experiments. The dynamic tension recovery technique was developed by adopting the improved bar system. Dynamic tension and recovery experiments were conducted to obtain adiabatic and isothermal stress-strain responses of the TC11 alloy at high strain rates. And the adiabatic softening effect was experimentally uncoupled from the strain-rate strengthening and strain hardening effects. The quasi-static tensile tests at different initial temperatures were also carried out to study the thermal softening effect which was described by Johnson-Cook model. The model was modified by introducing the value of adiabatic temperature rise in dynamic tensile process. When the adiabatic curves of the modified model and the experimental data are in good agreement, the conversion factors of plastic dissipation power to heat at different strain rates can be determined. And the conversion factor of the strain rate of 500 s^（-1） is found to be less than that of the strain rate of 190 s^（-1）.
作者
李云飞
曾祥国
Li Yunfei;Zeng Xiangguo(Sichuan University,Chengdu 610065,China;Institute of Systems Engineering,China Academy of Engineering Physics,Mianyang 621999,China)
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2018年第7期2056-2060,共5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)
