铁元素对铝镁焊料晶间腐蚀的影响  

Effects of Fe Element on Intergranular Corrosion of Al-Mg Filler Metal

作　　者：路全彬[1] 龙伟民[1] 董显[1] 纠永涛[1] 轩庆庆 

机构地区：[1]郑州机械研究所新型钎焊材料与技术国家重点实验室,郑州450000

出　　处：《表面技术》2016年第5期201-206,共6页Surface Technology

基　　金：国家国际科技合作计划项目(2014DFR50820)~~

摘　　要：目的研究Fe对铝镁焊料晶间腐蚀的影响规律,确定Fe元素的最佳含量。方法制备不同Fe元素含量的铝镁合金并进行表面处理,在3%(质量分数)Na Cl+10 m L/L HCl溶液中(35℃)浸泡24h,进行晶间腐蚀实验。通过扫描电子显微镜和光学显微镜对晶间腐蚀形貌和合金相进行分析。结果随着Fe元素含量的增加,合金试样最大腐蚀深度由133μm增加到179μm;Fe元素质量分数超过0.2%后,合金发生晶间腐蚀倾向大幅增加。引入Fe元素后,铝镁焊料合金相由α(Al)基体相+Al3Mg2相转变为α(Al)相+Al3Mg2相+Fe Al3相。随着Fe元素含量的增加,合金中富Fe相(Fe Al3)析出量增加,Fe Al3相形貌由最初的骨骼状转变为针片状和针状。Fe Al3相的增加提升了合金发生晶间腐蚀的原动力,增加了合金发生晶间腐蚀的敏感性。结论在铝镁焊料合金中引入Fe元素后,合金组织发生改变,导致合金抗晶间腐蚀能力下降。为降低合金发生晶间腐蚀的敏感性,应将Fe元素质量分数控制在0.2%以下,且越低越好。Objective To research the influencing law of Fe element on intergranular corrosion of A1-Mg filler metal, and determine the desirable Fe content of filler metal. Methods In this paper, A1-Mg alloys with different Fe addition were prepared. The surface of alloys was modified and then immersed into 3%NaC1 （mass fraction）＋10 mL/L HC1 aqueous solution for 24 hours at 35 ℃ to perform intergrannlar corrosion （IGC） experiments. Their morphologies were studied by SEM and Optical mi- croscopy （OM）. Results Maximum intergranular corrosion depths of alloys were improved from 133 μm to 179 μm by adding Fe. The intergranular corrosion resistance obviously decreased when the Fe content exceeded 0.2%. The original phase compo-sition of alloys were transformed from a（A1）＋A13Mg2 into a（A1）＋A13Mg2＋FeA13 with increasing Fe content. The morphology of FeA13 phase changed from skeleton into needle. The A1-Mg filler metal possessed high intergranular corrosion susceptibility with the increase of Fe-rich phases, which increased the motive force of intergranular corrosion. Conelusion The addition of Fe element could lead to structure change and thus reduce the intergranular corrosion resistance of alloys. To obtain high intergra- nular corrosion resistance, the Fe content in the alloy should be further reduced below 0.2%, and the lower the better.

关 键 词：铝镁合金 晶间腐蚀 杂质 微观组织 Fe添加 针状相 焊料 

分 类 号：TG422[金属学及工艺—焊接]