Fatigue Life of 6061 Aluminium Alloy Welding Samples both in Atmosphere and Water

名义厚度为0.04英寸（1.02 mm）的6061-O和6061-T4铝合金板材在航空工业里广泛使用。将这些板材在氩弧焊后淬火时效热处理至T62态后制成标准试样。在频率为60 Hz、应力比为0.1条件下，分别在大气和潮湿环境中进行疲劳试验，且施加载荷方向垂直于焊缝。断裂形貌通过扫描电子显微镜（SEM）观察。结果表明：与大气环境中相比，焊缝在潮湿环境下疲劳性能急剧下降，而且疲劳带也不是很明显。焊缝在潮湿环境下断裂表面含氧量比在大气中高是可能的原因。

Fatigue Life of 6061 Aluminium Alloy Welding Samples both in Atmosphere and Water

6061-O and 6061-T4 aluminum alloy sheets with 0.04 inch (1.02 mm) nominal thickness are widely used in the aviation industry. After argon arc welding, the sheets were subjected to a solution heat treatment followed by a quenching and tempering treatment (T62 treatment), afterwards fabricated to specimens. The fatigue tests were carried out at 60 Hz, stress ratio of 0.1 both in atmosphere and water at room temperature, and loading direction was perpendicular to welding bead. The fracture morphologies were examined by scanning electron microscopy (SEM). The results show that the fatigue life in water is considerably decreased, and fatigue striation is not so clear compared with that in atmosphere, which might be attributed to the fact that the oxygen content on the fracture surface tested in water after dry treatment is much higher than that in atmosphere.