长时腐蚀过程中异种材料连接结构的失效机理与性能弱化机制

Failureand Degenerate Mechanism of Dissimilar Metal Connection Structures in Long-term Corrosion Process

电偶腐蚀是腐蚀环境下异种材料连接结构的重要失效形式。采用浸泡腐蚀试验开展了异种材料连接结构在3.5%NaCl溶液中的腐蚀行为研究,并通过扫描电子显微镜(scanning electron microscopy,SEM)和材料拉伸实验对试样的腐蚀形貌观察和力学性能测试,分析了长时腐蚀过程中异种材料连接结构的失效机理与性能弱化机制。研究结果表明,电偶因素和缝隙腐蚀因素联合作用使2A12铝合金的力学性能指标明显降低,但是对强度指标(屈服强度和断裂强度)的影响程度没有对塑性指标(延伸率和断面收缩率)的影响程度大。

Galvanic corrosion is an important failure forms of bonded dissimilar materials under corrosive environmental conditions.Galvanic corrosion behavior of dissimilar metal connection structure in 3.5%NaCl solution were conducted by using immersion corrosion tests,and the corrosion morphology and mechanical property were analyzed by scanning electron microscopy(SEM)and uniaxial tensile tests,which aimed to investigate failure and degenerate mechanism of dissimilar metal connection structures,respectively.The results showed that the coupling of galvanic corrosion and crevice corrosion can decrease the mechanical properties of 2A12 specimens,and the effects of corrosion on intensity index(yield strength and fracture strength)of 2A12 specimens is less than on plasticity index(elongation and cross-sectional shrinkage).