不同应力水平下2A12/40CrNiMoA的电偶腐蚀行为及其对材料性能的影响研究  

Research on Galvanic Corrosion Behavior of 2A12/40CrNiMoA Couple and Its Effects on Properties of Material Under Different External Stress

作　　者：史平安[1] 帅茂兵[2] 刘道新[3] 莫军[1] 尹益辉[1] 万方美[1] 周宏亮[1] 刘剑钊[1] 

机构地区：[1]中国工程物理研究院总体工程研究所,四川绵阳621900 [2]中国工程物理研究院表面物理和化学国家重点实验室,四川绵阳621907 [3]西北工业大学腐蚀与防护研究室,陕西西安710072

出　　处：《热加工工艺》2013年第12期1-6,共6页Hot Working Technology

基　　金：中国工程物理研究院重大基金资助项目(2009A0302018)

摘　　要：为研究外加应力对金属材料电偶腐蚀行为的影响,采用电化学法和浸泡法研究了不同应力水平下电偶对2A12/40CrNiMoA的电偶腐蚀行为,利用金相显微镜和扫描电镜对试样腐蚀后的表面形貌特征和腐蚀产物的结构进行观察。结果表明,2A12承受的应力水平增大,电偶电流密度增加,电偶腐蚀敏感性提高;无外加应力时,作为阳极的2A12铝合金表面的腐蚀形式是局部的点蚀,并伴有少量晶间腐蚀;外加应力增加到75%σs时2A12铝合金表面腐蚀明显加剧,大量孔蚀相连,形成严重均匀腐蚀。因此,应力对2A12铝合金腐蚀行为有较大影响。根据实验得到的不同腐蚀周期内2A12铝合金的腐蚀特征和质量损失率,建立了腐蚀损伤材料力学性能的预测模型。通过对理论计算和实验测试结果的对比,两者吻合较好,这证明了本模型和方法的可行性。The galvanic corrosion behaviors of 2A12 AI alloy coupled with 40CrNiMoA steel under tensile stress level were studied by galvanic method and immersion test. The surface morphologies of the samples were observed by SEM, and XRD was used to analyze the crystal corrosion products. The results show that the couple current density and galvanic corrosion sensitivity increases with the increase of external stress. The corrosion forms of the couple of 2A12/40CrNiMoA in 3.5%NaCI solution was general corrosion and localized corrosion including intergranular corrosion and pitting corrosion without the effect of external stress. As stress was applied to the alloy, the pits of 2A12 develops into larger dimension and the intergranular corrosion penetrates into the matrix when the external stress increases to 75%0% Based on the characteristics of corrosion metrics and micro-mechanics and the mass loss rate of the alloy in different external stress and corrosion time, a model was established to predict the mechanical properties of the alloy. The accuracy of the model and method is assured by comparing predicted results with those of tests.

关 键 词：外加应力 电偶腐蚀 质量损失率 力学性能 

分 类 号：TG113.231[金属学及工艺—物理冶金]