A shear band decohesion model for small fatigue carck growth in an ultra-fine grain aluminium alloy
A shear band decohesion model for small fatigue carck growth in an ultra-fine grain aluminium alloy
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DOI：
10.1016/s0013-7944(99)00148-4
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发表时间：
2000-04
影响因子：
5.4
通讯作者：
J. Zhang
中科院分区：
文献类型：
--
作者：
J. Zhang
对超细晶粒铝合金 IN 9052 的小疲劳裂纹扩展行为进行了研究。在实验室空气中和场发射枪扫描电子显微镜的真空室中对样品进行 R∼0.1 张力-张力测试。在扫描电镜内进行加载和卸载实验，以研究裂纹面的位移、裂纹尖端的形状变化、裂纹尖端周围的剪切带以及疲劳裂纹扩展机制。原位SEM观察表明，裂纹尖端区域形成的剪切带与裂纹的扩展机制直接相关。剪切带将脱聚集中在裂纹尖端区域，并且观察到在载荷循环的加载部分期间发生沿着剪切带的裂纹。通过超细晶材料中小裂纹扩展的定性模型总结了承受循环载荷的裂纹尖端区域的整体行为。
A study of small fatigue crack growth behaviour of an ultra-fine grain size aluminum alloy IN 9052 has been carried out. Specimens were tested in tension–tension at R∼0.1 in laboratory air and in the vacuum chamber of a field emission gun scanning electron microscope. Loading and unloading experiments were carried out within the SEM to study the displacements of the crack faces, the shape change at the crack tip, the shear bands around the crack tip and the fatigue crack growth mechanism. The in-situ SEM observations revealed that shear bands formed in the crack tip region were directly associated with the growth mechanism of the crack. The shear bands localized the decohesion in the crack tip region and the cracking along the shear bands was observed to occur during the loading part of the load cycle. The overall behaviour of the crack tip region subjected to cyclic loading is summarized by a qualitative model for small crack growth in an ultra-fine grained material.