Cyclic deformation and fatigue of extruded Mg–Gd–Y magnesium alloy
Cyclic deformation and fatigue of extruded Mg–Gd–Y magnesium alloy
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DOI：
10.1016/j.msea.2012.10.048
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发表时间：
2013-01
期刊：
影响因子：
6.4
通讯作者：
Fenghua Wang;Jie Dong;Yanyao Jiang;W. Ding
中科院分区：
文献类型：
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作者：
Fenghua Wang;Jie Dong;Yanyao Jiang;W. Ding
在应变幅值为0.275%~5.0%的挤压方向上进行了全逆应变控制的拉伸-压缩实验，研究了稀土镁合金挤压后的循环变形和疲劳行为。单调拉伸和压缩应力-应变曲线表现出从弹性变形到弹塑性变形的平稳过渡，并表现出相当屈服的对称性。与常规镁合金不同的是，在完全反向应变控制实验中，该材料表现出近对称的应力-应变滞后曲线和边缘循环硬化，平均应力几乎为零。随着加载循环次数的增加，当应变幅值大于2.0%时，拉伸和压缩方向的应力-应变响应都发生了从凹形向S形的转变。应变-寿命疲劳曲线显示出与常规镁合金相似的特征：在应变幅值为0.75%附近的拐点处，出现明显的从低周向高周的转变。讨论了GW83镁合金的循环变形和疲劳性能及其相关的循环变形机制，并与典型的常规镁合金进行了比较。
Cyclic deformation and fatigue of extruded rare-earth Mg–8.0Gd–3.0Y–0.5%Zr (GW83) magnesium (Mg) alloy were experimentally investigated by carrying out fully reversed strain-controlled tension–compression experiments along the extrusion direction with the strain amplitudes varying from 0.275% to 5.0%. Monotonic tension and compression stress–strain curves display a smooth transition from elastic to elastic–plastic deformation and exhibit a fairly yielding symmetry. Different from conventional Mg alloys, the material shows near-symmetric stress–strain hysteresis loops and marginal cyclic hardening with almost zero mean stress in the fully reversed strain-controlled experiments conducted. With increasing number of loading cycles, a transition of stress–strain response from concave-down shape to sigmoidal shape occurs in both tension and compression reversals when the strain amplitudes are larger than 2.0%. The strain-life fatigue curve displays a similar feature to that of conventional Mg alloys: A detectable transition from low-cycle region to high-cycle region occurs at a kink point in the vicinity of a strain amplitude of 0.75%. The cyclic deformation and fatigue properties of GW83 Mg alloy and the associated cyclic deformation mechanism are discussed and compared with those of a typical conventional Mg alloy.