基于元胞自动机法的AA7075-T651铝合金在力-化学交互作用下腐蚀损伤特征演化规律研究

Evolution of Corrosion Damage Characteristics of AA7075-T651 Al-alloy Under Mechanical-chemical Interaction Based on Cellular Automata Method

为合理阐明力-化学交互作用下AA7075-T651铝合金腐蚀损伤特征的演化规律,本研究采用元胞自动机法和力学数值仿真软件联合方法,模拟了铝合金在不同载荷水平下的腐蚀损伤演化过程,系统地探究了机械应力对材料腐蚀生长速率及形貌特征演化的影响。研究结果显示,相较于无外加载荷作用下的材料腐蚀,力-化学耦合作用下材料腐蚀损失的元胞数量、最大腐蚀深度或宽度均明显增大,且从腐蚀损伤特征的最大腐蚀深度/宽度比值随着载荷水平的增加逐渐上升可以看出,拉伸应力造成腐蚀坑在纵向上呈现出更快的生长趋势,进而造成应力集中系数增加,使得腐蚀损伤特征底部由弹性变形转变为塑性变形,最终加速了金属的腐蚀进程。

The evolution of corrosion damage characteristics of AA7075-T651 Al-alloy under combined force-chemical interaction was clarified via a combination of cellular automaton method and mechanical numerical simulation software,aiming to simulate the evolution process of corrosion damage of Al-alloy under different load levels,and to revealing the effect of mechanical stress on the variation of corrosion growth rate and morphological characteristics evolution of the Al-alloy as well.The results show that compared with the corrosion of Al-alloy without external load,the number of cells lost due to the corrosion and the maximum corrosion depth or width under the action of force-chemical coupling are significantly increased,while the maximum ratio of corrosion depth to width of the corrosion damage characteristics are significantly increased.It can be seen that the ratio of depth to width gradually increases with the increase of load level.It can be seen that the tensile stress causes the corrosion pit to show a faster growth trend in the longitudinal direction,which in turn causes the stress concentration coefficient to increase,causing the bottom of the corrosion damage characteristic to change from elastic deformation to plastic deformation,ultimately accelerating the corrosion process of the Al-alloy.