【摘 要】
：
采用扫描电镜和透射电镜对7075铝合金缸体出现的断裂现象进行了显微组织观察和失效分析。结果表明,7075铝合金缸体疲劳裂纹的萌生与阳极氧化膜有关,其表面的微孔洞在循环应力
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采用扫描电镜和透射电镜对7075铝合金缸体出现的断裂现象进行了显微组织观察和失效分析。结果表明,7075铝合金缸体疲劳裂纹的萌生与阳极氧化膜有关,其表面的微孔洞在循环应力作用下容易产生应力集中,从而成为疲劳裂纹形核的场所。防止措施:建议将过渡圆弧半径加大以降低应力集中,减少疲劳裂纹萌生的可能性。
The fracture phenomena of 7075 aluminum alloy cylinder was observed by microscopy and transmission electron microscopy. The results show that the initiation of fatigue crack in 7075 aluminum alloy cylinder is related to the anodic oxide film. The micro-cavities on the surface of the 7075 aluminum alloy cylinder are prone to stress concentration under the cyclic stress and become the sites of fatigue crack nucleation. Preventive measures: It is recommended to increase the transition arc radius to reduce stress concentration, reduce the possibility of fatigue crack initiation.
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