Small crack initiation and early propagation in an as-extruded Mg-10Gd-3Y-0.5Zr alloy in high cycle fatigue regime
Small crack initiation and early propagation in an as-extruded Mg-10Gd-3Y-0.5Zr alloy in high cycle fatigue regime
复制标题
挤压态 Mg-10Gd-3Y-0.5Zr 合金在高周疲劳状态下的小裂纹萌生和早期扩展
DOI：
10.1016/j.msea.2018.10.015
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发表时间：
2019-01-28
期刊：
影响因子：
6.4
通讯作者：
Chen, Qiang
中科院分区：
文献类型：
--
作者：
He, Chao;Shao, Xiaohong;Chen, Qiang
对挤压态Mg-10 Gd-3 Y-0.5Zr合金进行了高周疲劳试验，研究了其疲劳裂纹萌生和早期扩展行为。实验结果表明，在低循环应力幅下，只有基底滑移被激活。疲劳裂纹从滑移带沿着基面萌生，导致断口上解理状小面的形成。在高周疲劳状态下，裂纹萌生点附近刻面的形成消耗了绝大部分的循环载荷，而小裂纹的扩展则受到邻近晶粒局部微观结构不均匀性的显著阻碍。这可能是由于低循环应力下的非协调变形，导致滑移带在孤立的晶粒内局部化。
High cycle fatigue testing was performed on an as-extruded Mg-10Gd-3Y-0.5Zr alloy to investigate its fatigue crack initiation and early propagation behaviors. Experimental results showed that only basal slip was activated at a low cyclic stress amplitude. Fatigue crack initiated from the slip bands along the basal plane, leading to the formation of cleavage-like facets on the fracture surface. The formation of facets around the crack initiation sites consumed a vast majority of the cyclic loadings in high cycle fatigue regime, and small fatigue crack propagation was significantly retarded by local microstructure heterogeneity of neighboring grains. This can be ascribed to the incompatible deformation at low cyclic stresses, resulting in the localization of slip bands within isolated grains.