拉应力与电偶因素对2E12铝合金腐蚀行为的影响

Effect of the Tensile Stress and Galvanic Factors on the Corrosion Behavior of 2E12 Aluminum Alloy

为探讨应力和电偶双重因素对2E12-T3铝合金腐蚀行为的影响,采用应力腐蚀试验,电偶腐蚀试验以及电化学阻抗技术、金相技术、扫描电镜分析技术,研究了应力和电偶双重因素对铝合金腐蚀行为的作用机理。研究结果表明:2E12-T3在NaCl-H2O2溶液中具有很高的应力腐蚀敏感性。未偶接不锈钢时,随着所受外加拉应力水平的提高,铝合金表面阻抗略有降低,合金抗腐蚀能力下降,外加拉应力提高了铝合金的腐蚀敏感程度。偶接不锈钢后,同应力条件下的阻抗值较偶接前低很多,并且相同应力水平下的断裂时间缩短为未偶接时的1/3,电偶因素起到了很大的作用。在应力因素和电偶因素的共同作用下,铝合金腐蚀敏感性非常高。

In order to study the effect of the stress and galvanic factors on the corrosion behavior of 2E12-T3 alumi- num alloy, the stress corrosion experiment, galvanic corrosion experiment, electrochemical impedance techniques, metallography techniques and scanning electron microscope （SEM） were used to study the mechanism. The results show that： in NaC1-H202 solution, the corrosion resistance of 2E12-T3 is low and the aluminum alloy has high stress corrosion sensitivity. When the aluminum alloy is not coupled to stainless steel, with increase of the tensile stress, the surface impedance of aluminum alloy is slightly reduced, and the resistance to corrosion fell. The tensile stress increases the corrosion degree of aluminum alloy. When coupled to stainless steel, at the same stress condi- tions, the impedance of the aluminum alloy is lower than that not coupled to stainless steel. After coupled to stain- less steel, the aluminum alloy＇s fracture time is shorten 1/3. The galvanic factors play a significant role. Under the condition of stress and galvanic, the corrosion sensitivity of aluminum alloy is very high.