LY12CZ铝合金型材的腐蚀动力学统计规律研究及日历寿命预测方法探讨

STATISTICAL STUDY OF CORROSION DYNAMICS LAW AND METHOD TO PREDICT CALENDAR LIFE FOR LY12CZ ALUMINUM ALLOY

以周期浸泡试验作为加速腐蚀试验 ,以最大腐蚀深度作为腐蚀损伤衡量指标 ,研究了 LY1 2 CZ铝合金型材腐蚀的统计规律和动力学规律。结果发现 :LY1 2 CZ铝合金型材的最大腐蚀深度符合 Gumbel统计规律 ;对于一定的面积 (一定的失效概率 ) ,最大腐蚀深度随时间变化的动力学曲线为 S形曲线 ,必须分为点蚀阶段 ( Sigmoidal( Boltzman)曲线 )、剥蚀阶段 (直线 )两部分进行拟合。在此基础上 ,提出了根据研究对象的面积、腐蚀损伤容限、周期浸泡试验的加速系数及最大腐蚀深度、面积。

In this article, alternate immersion tests were applied to bare 2024T3 alloy. Maximum corrosion depth was measured to evaluate the severity of corrosion. Since localized corrosion is a stochastic phenomenon, a statistic method was also used to deal with the data. The results showed that the maximum corrosion depth was consistent with the Gumbel distribution law. For certain area of the specimen, the dynamic variation curve of the maximum corrosion depth vs the test period must be divided into two stages to treat the data, i.e. pitting (sigmoidal curve) and exfoliation ( line), in order to make the simulation. The relationship among the maximum depth, the area and the test time was established. A new life prediction method for natural environmental service was proposed: according to the area of the object, the corrosion loss allowance, accelerated coefficient of alternate immersion test and the above function, the life of bare LY12CZ aluminum alloy can be predicted.