Fatigue of as-extruded AZ61A magnesium alloy
Fatigue of as-extruded AZ61A magnesium alloy
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DOI：
10.1016/s0921-5093(01)01411-3
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发表时间：
2002-02
期刊：
影响因子：
6.4
通讯作者：
T. Shih;Wen-Sun Liu;Ye Chen
中科院分区：
文献类型：
--
作者：
T. Shih;Wen-Sun Liu;Ye Chen
将由挤压态AZ 61 A棒材（直径18 mm）制备的样品用于旋转弯曲试验。建立了应力幅与失效循环次数之间的关系，以及在两个特定应力幅下的失效循环次数。还分析了在这两个特定应力水平下的失效概率。本研究最终提供了不同概率（10 - 90%）下107次循环的预测疲劳强度。断口分析表明，疲劳裂纹是由表面或次表面夹杂物引起的。这些夹杂物附近的表面作为应力集中和诱导集群的滑移带在旋转弯曲试验。启裂后，裂纹在主导剪切应力下扩展，导致大面积解理断裂。微观裂纹发生，导致从钝化过程中发展的诱导变形孪晶。因此，裂纹的扩展遵循微观裂纹的存在，并导致穿晶断裂。
Samples prepared from as-extruded AZ61A bars (18mm in diameter) were used in a rotating bending test. The relation between stress amplitude and cycles to failure has been constructed, as well as the cycles to failure at two specific stress amplitudes. The probability of failure at these two specific stress levels was also analyzed. This study finally provided the predicted fatigue strength at 107cycles with different probabilities (10 to 90%). A fractography study indicated that fatigue cracking initiated from subsurface or surface inclusions. These inclusions near the surface served as stress raisers and induced clusters of slip bands during the rotating bending test. After initiation, the cracks grew under the dominant shear stress and resulted in a cleavage fracture over a large area. Microscopic cracks occurred, resulting from the induced deformation twins that developed from the blunting process. Consequently, the propagation of cracks followed the existence of microscopic cracks and resulted in a transgranular fracture.