Effect of stress ratio on high cycle fatigue properties in Mg-6Zn-1Mn alloy
Effect of stress ratio on high cycle fatigue properties in Mg-6Zn-1Mn alloy
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DOI：
10.1016/j.msea.2017.10.082
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发表时间：
2018-01
期刊：
影响因子：
6.4
通讯作者：
Daliang Yu;Dingfei Zhang;Q. Dai;Wei Lan;J. Peng;Junyao Xu;Fugang Qi;F. Pan
中科院分区：
文献类型：
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作者：
Daliang Yu;Dingfei Zhang;Q. Dai;Wei Lan;J. Peng;Junyao Xu;Fugang Qi;F. Pan
研究了加载方式对Mg-6Zn-1Mn(ZM61)合金高周疲劳性能的影响。本研究采用挤压、T5处理和双时效ZM61合金。高周疲劳试验分别在零拉伸载荷(R=0)和全反拉压载荷(R=−1)下由伺服液压疲劳试验机进行。结果表明，三种合金在零拉伸载荷下的高周疲劳强度均高于拉压载荷下的高周疲劳强度。通过对疲劳后组织的观察，发现零拉伸试样中出现了大量的小角度晶界，而拉压加载试件中出现了{101̅2}孪晶。疲劳性能在零拉伸载荷和拉压载荷下的变化与不同载荷条件下的变形机制有关。在零拉伸载荷下，镁合金的疲劳变形机制主要是位错滑移，而在拉压载荷下，压缩半周内的{101̅2}孪晶的激活导致了疲劳强度的恶化。
This work investigated the effect of loading mode on high cycle fatigue properties in Mg-6Zn-1Mn (ZM61) alloys. Extruded, T5 treated and double-aged ZM61 alloys were used in this study. High cycle fatigue tests were carried by a servo-hydraulic fatigue testing system under zero-tension load (R= 0) and fully reversed tension-compression load (R=− 1), respectively. The results showed that all the three alloys exhibited more outstanding high cycle fatigue strength under zero-tension load than under tension-compression load. By observing microstructures of post-fatigued specimens, a large number of low angle grain boundaries appeared in zero-tension load specimens, but {10 1 ̅ 2} twins were found in tension-compression load specimens. The variations of fatigue properties in zero-tension load and tension-compression load were related to deformation mechanisms under different load conditions. The fatigue deformation mechanism in Mg-6Zn-1Mn alloy under zero-tension load was mainly dislocation slip, while under tension-compression load, the activation of {10 1 ̅ 2} twinning in compression half cycles resulted in the deteriorative fatigue strength.