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董鹏, 孙大千, 李洪梅, 王冰. 6005A铝合金搅拌摩擦焊接头的晶间腐蚀行为[J]. 焊接学报, 2014, 35(5): 105-108.
引用本文: 董鹏, 孙大千, 李洪梅, 王冰. 6005A铝合金搅拌摩擦焊接头的晶间腐蚀行为[J]. 焊接学报, 2014, 35(5): 105-108.
DONG Peng, SUN Daqian, LI Hongmei, WANG Bing. Intergranular corrosion behaviour of friction stir welded joints of 6005A aluminium alloy[J]. TRANSACTIONS OF THE CHINA WELDING INSTITUTION, 2014, 35(5): 105-108.
Citation: DONG Peng, SUN Daqian, LI Hongmei, WANG Bing. Intergranular corrosion behaviour of friction stir welded joints of 6005A aluminium alloy[J]. TRANSACTIONS OF THE CHINA WELDING INSTITUTION, 2014, 35(5): 105-108.

6005A铝合金搅拌摩擦焊接头的晶间腐蚀行为

Intergranular corrosion behaviour of friction stir welded joints of 6005A aluminium alloy

  • 摘要: 对6005A铝合金搅拌摩擦焊接头的晶间腐蚀行为进行了研究.结果表明,母材的晶间腐蚀倾向最大,热影响区(HAZ)次之,焊核区(NZ)和热力影响区(TMAZ)的晶间腐蚀倾向最低.结合场发射扫描电镜、高分辨透射电镜分析解释了接头不同区域的腐蚀行为:母材的晶间腐蚀是两组微电池效应的结果,即晶界析出相/沉淀无析出带(PFZ)和铝基体/PFZ;HAZ内晶界析出相的数量的减少、间距的变大及晶内Q'相的析出显著改善了该区的晶间腐蚀性,但晶内Q'相的析出也引起了点蚀的发生;NZ和TMAZ内绝大部分的合金元素固溶于基体,抑制了晶间腐蚀的发生.

     

    Abstract: The intergranular corrosion (IGC) behaviour of friction stir welded 6005A aluminium alloy was investigated. The results show that the base material(BM) is the most susceptible to IGC and the heat affected zone (HAZ) takes the second place,while the nugget zone (NZ) and thermo-mechanically affected zone (TMAZ) show high resistance to IGC. The corrosion behaviour in different zones could be well explained from microstructural observation by means of field emission scanning electron microscope (FE-SEM) and high-resolution transmission electron microscopy (HRTEM). IGC in the BM was caused by two microgalvanic couplings of precipitate free zone (PFZ,anode)/cathodic precipitates (Q and Si phases) and the PFZ (anode)/matrix. The coarsening of the intergranular precipitates as well as the precipitation of the intragranular Q' phases in the HAZ reduced the microgalvanic driving force causing IGC and introduced the pitting corrosion. The relatively homogeneous microstructure both in NZ and TMAZ restrained the occurrence of IGC.

     

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