应力比对航空高强LD2CZ铝合金腐蚀疲劳裂纹扩展的影响

利用扫描电镜联合液压伺服试验机，并借助于Walker公式研究了应力比对预腐蚀不同时间航空高强LD2CZ铝合金疲劳裂纹扩展的影响，在应力比分别为0．05，0．5，0．7的条件下对预腐蚀0，15，30d的LD2CZ铝合金单边缺口板状试样进行了疲劳加载试验，得到了其疲劳裂纹扩展速率曲线，并拟合出了Walker公式中的材料常数。结果表明：裂纹扩展速率会随着应力比的增加以及腐蚀损伤的加深而增大，拟舍得到的Walker公式可用来定量化地表征应力比和腐蚀损伤对疲劳裂纹扩展速率的影响。

Effects of Stress Ratios on Aero High-strength LD2CZ Aluminum Alloy Fatigue Crack Growth with Corrosion Damage

The effects of stress ratios on fatigue cracks growth of aero high-strength LD2CZ aluminum alloy with corrosion damage were studied with Walker equation with the aid of SS550 scanning electron microscopy combined with server hydraulic fatigue test machine. Fatigue tests were executed at stress ratios of 0. 05, 0. 5, 0. 7 for specimens with corrosion damage equivalent to 0, 15, 30 days exposure in certain natural airport environment respectively. The fatigue crack growth curves were obtained, and based on that the parameters in Walker equation were computed out. The results indicate that fatigue cracks growth rate would increase with the increase of stress ratio and corrosion damage. According to the obtained Walker equation, the effects of stress ratios and corrosion damage on the fatigue cracks growth rate could be characterized quantitatively.