铝合金力学与电化学耦合点蚀扩展模型研究

Research on the Mechanical and Electrochemical Coupling Pitting Growth Model of Aluminum Alloy

点蚀是航空铝合金材料在服役环境下常见的损伤形式,作为承力构件,航空铝合金不仅承受环境腐蚀的作用,还承受应力作用。根据点蚀基本原理和力学化学效应计算推导出了铝合金在腐蚀介质中腐蚀深度随时间和应力的关系表达式,定量化揭示外力作用对金属腐蚀的影响。利用电位扫描技术及显微测量技术研究了腐蚀坑深度随时间和载荷的变化,并对腐蚀后试验件的损伤宏观形貌和微观形貌进行观察分析。模型计算与试验结果的对比证明了本方法的可行性与正确性。本研究将有助于提高结构件设计的可靠性,增加寿命预测的准确性,具有较高的实用价值和经济价值。

Pitting corrosion is one of the common damages of aviation aluminum alloy materials in service environment. As a bearing member, aviation aluminum alloy not only bears the effect of environmental corrosion, but also the stress. According to the basic principles of pitting corrosion and the calculation of mechanical chemical effects, the relationship between the corrosion depth of aluminum alloy in corrosive medium with time and stress was derived, which quantitatively revealed the influence of external force on metal corrosion. In addition, the potential scanning technique and micro - measurement technique were employed to study the depth variations of corrosion pits as time and load and observe the macro/micro damage morphologies of samples after corrosion. The comparison between the model calculation and the experimental results proved the feasibility and correctness of the proposed method. This study will help to improve the reliability of structural design and increase the accuracy of life prediction, which present high practical value and economic value.