A study of the back stress and the friction stress behaviors of Ti-6Al-4V alloy during low cycle fatigue at room temperature
A study of the back stress and the friction stress behaviors of Ti-6Al-4V alloy during low cycle fatigue at room temperature
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DOI：
10.1016/j.msea.2017.06.051
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发表时间：
2017-07
期刊：
影响因子：
6.4
通讯作者：
Haifeng Xu;Du-yi Ye;L. Mei
中科院分区：
文献类型：
--
作者：
Haifeng Xu;Du-yi Ye;L. Mei
在室温下对 Ti-6Al-4V 合金进行低周疲劳（LCF）试验。测定钛合金的疲劳硬化/软化。背应力 (X) 和摩擦应力 (σF) 均通过疲劳磁滞回线分析进行评估，并通过实验获得疲劳测试期间它们的循环相关行为。结果表明，钛合金的循环应力响应或疲劳硬化/软化实际上是疲劳循环过程中背部竞争效应和摩擦应力行为的结果。还获得了 εpa-2Nf 和 X-2Nf 图中的双斜率行为。借助疲劳失效样本在代表性应变幅度下的 OM 和 TEM 观察，进一步讨论了与背应力和摩擦应力行为以及 εpa-2Nf 和 X-2Nf 图中的双斜率行为相关的微观机制。在本研究中，还引入了 DIC 技术来定量表征钛合金晶粒尺度的循环变形不均匀性。
Low cycle fatigue (LCF) tests were performed on Ti-6Al-4V alloy at room temperature. The fatigue hardening/softening of the Ti-alloy were determined. Both the back stress (X) and the friction stress (σF) were evaluated from analysis of fatigue hysteresis loops and their cycle-dependent behaviors during fatigue tests were obtained experimentally. It is shown that the cyclic stress response or the fatigue hardening/softening of the Ti-alloy actually results from the competition effect of the back and the friction stress behaviors during fatigue cycling. A two-slope behavior in both theεpa-2Nfand theX-2Nfplots was also obtained. The micro-mechanisms associated with the back and friction stress behaviors as well as the two-slope behavior in theεpa-2NfandX-2Nfplots were further discussed with the help of OM and TEM observations of fatigue failure specimens at representative strain amplitudes. In this study, the DIC technique was also introduced to characterize quantitatively the cyclic deformation heterogeneity of the Ti-alloy at the grain scale.