时效状态对新型Al-Cu-Li系合金剥落腐蚀性能的影响

研究了一种新型Al-Cu-Li系合金在T6、T8两种时效状态的剥落腐蚀行为,根据电化学阻抗谱,结合显微组织形貌分析了其腐蚀机理.研究表明,两种时效状态的合金几乎同时发生点蚀,T8态合金剥落腐蚀要比经T6态合金发生晚.着重讨论了合金中T1相对腐蚀的影响,实验表明,时效前的预变形(6%)使T1相析出细小、均匀,有利于提高该合金的抗剥落腐蚀性能.

Study on exfoliation corrosion of T6 aged T8 aged of a new type Al-Cu-Li alloy

Exfoliation corrosion of T6 aged and T8 aged of a new type Al-Cu-Li alloy was studied. The investigation showed that spot corrosion of the alloy with different aging treatment occurred almost at the same time, and the exfoliation of samples with T8 aged took was shorter than that of T6 aged alloy. The EIS of samples in EXCO solution was comprised by a depressed capacitive arc at high frequency and an inductive arc at low frequency without exfoliation while after exfoliation the EIS was comprised of two capacitive arcs at high frequency and at low frequency, respectively. The mechanics and phenomenon of corrosion was analysised with microstructure, which showed that the smaller capacity and homogenous distribution of precipitates in T8 alloy because of the deforming before aging can hindrance the occurring of exfoliation effectively.