7050铝合金晶界偏析与应力腐蚀、腐蚀疲劳行为的研究

INVESTIGATION OF RELATION BETWEEN GRAIN BOUNDARY SEGREGATION AND BEHAVIOR OF STRESS CORROSION AND CORROSION FATIGUE IN 7050 ALUMINIUM ALLOY

研究了不同时效状态的７０５０铝合金晶界偏析与应力腐蚀开裂及湿空气环境下疲劳裂纹扩展的关系，并采用修正的化学方法计算了晶界偏析对断裂应力的影响。结果表明：随着时效程度的增加，晶界上Ｍｇ偏析浓度减小，捕获Ｈ的能力减弱，晶界断裂应力的百分数随之下降，因而合金的抗应力腐蚀和腐蚀疲劳性能提高。

The relationship between grain boundary segregation and crack growth of stress corrosion and corrosion fatigue in 7050 aluminium alloy was investigated under various aging conditions in moist air environment. The effect of grain boundary segregation on fracture stress was also calculated using modified quasi-chemical approach. The results indicated that with increasing aging degree, the concentration of Mg segregated on grain boundary decreased and the ability of grain boundary to capture hydrogen was weakened, thus resulting in the decreasing percentage of grain boundary fracture stress reduction. It implied that the stress corrosion cracking susceptibility of the high strength aluminium alloy decreased and its corrosion fatigue resistance was improved.