Strain-Rate-Dependent Tensile Response of Ti-5Al-2.5Sn Alloy
Strain-Rate-Dependent Tensile Response of Ti-5Al-2.5Sn Alloy
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Ti-5Al-2.5Sn 合金应变率相关的拉伸响应
DOI：
10.3390/ma12040659
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发表时间：
2019-02-02
期刊：
影响因子：
3.4
通讯作者：
Li, Ziran
中科院分区：
文献类型：
--
作者：
Zhang, Bin;Wang, Jin;Li, Ziran
本文对Ti-5Al-2.5Sn合金在宽应变率范围内的拉伸响应进行了实验研究。利用液压驱动的MTS 810试验机和中等应变率试验系统，在10（-3）-10（1）s（-1）的应变率范围内进行单轴拉伸试验。采用分离式Hopkinson拉杆进行了高速单轴拉伸和拉伸回复试验，获得了动态加载条件下该合金的绝热和等温应力-应变响应。实验结果表明，初始屈服应力值随应变速率的增加而增大，但在高应变速率下，应变速率敏感性较大。等温应变硬化行为随应变速率变化不大，绝热温升是高应变速率拉伸时应变硬化速率降低的主要原因。电子背散射衍射（EBSD）分析表明，在准静态和高速拉伸载荷下，变形后的样品中存在形变孪晶。扫描电子显微镜（SEM）的变形后的样品的断裂表面的显微照片显示韧窝样的功能。对Zerilli-Armstrong模型进行了修正，使其考虑了高应变率下绝热温升的热软化效应，并描述了Ti-5Al-2.5Sn合金在准静态到1050 s（-1）应变率范围内的拉伸响应。
This study is an experimental investigation on the tensile responses of Ti-5Al-2.5Sn alloy over a wide range of strain rates. Uniaxial tension tests within the rate range of 10(-3)-10(1) s(-1) are performed using a hydraulic driven MTS810 machine and a moderate strain-rate testing system. The high-rate uniaxial tension and tension recovery tests are conducted using a split-Hopkinson tension bar to obtain the adiabatic and isothermal stress-strain responses of the alloy under dynamic loading conditions. The experimental results show that the value of the initial yield stress increases with the increasing strain rate, while the strain rate sensitivity is greater at high strain rates. The isothermal strain-hardening behavior changes little with the strain rate, and the adiabatic temperature rise is the main reason for the reduction of the strain-hardening rate during high strain-rate tension. The electron backscatter diffraction (EBSD) analysis of the post-deformed samples indicates that there are deformation twins under quasi-static and high-rate tensile loadings. Scanning electron microscope (SEM) micrographs of the fracture surfaces of the post-deformed samples show dimple-like features. The Zerilli-Armstrong model is modified to incorporate the thermal-softening effect of the adiabatic temperature rise at high strain rates and describe the tension responses of Ti-5Al-2.5Sn alloy over strain rates from quasi-static to 1050 s(-1).