2219铝合金搅拌摩擦焊接头晶间腐蚀分析

Analysis of intergranular corrosion of friction stir welded 2219 aluminium alloy

采用晶间腐蚀试验研究了2219铝合金搅拌摩擦焊接头的晶间腐蚀行为,结合接头显微组织、微观硬度、腐蚀形貌及腐蚀深度,分析母材与焊核区的差异,并对接头晶间腐蚀机理进行了初步的探讨.结果表明,焊核区为细小的等轴晶组织,且接头上表面焊核区的晶粒要大于下表面焊核区的晶粒;母材区硬度最高,下表面焊核区硬度最低;焊核区的耐蚀性优于母材,且上表面焊核区耐蚀性优于下表面焊核区,母材最大腐蚀深度为145.9μm,上表面焊核区及下表面焊核区最大腐蚀深度为46.3μm和84.1μm.

The intergranular corrosion behavior of friction stir welded 2219 aluminium alloy was investigated. Microstructure,micro-hardness,corrosion morphology and corrosion depth were studied to analyze the difference between BM and WNZ,and intergranular corrosion mechanism of FSW joint was preliminary discussed. The results show that WNZ consists of fine equiaxed grains,and the grain size on top surface is slightly bigger than that on root surface. The highest microhardness is located in the BM while the lowest in the WNZ on root surface. The corrosion resistance of WNZ is much superior than that of BM,and WNZ on top surface is slightly superior than that on root surface.The maximum corrosion depth in BM is 145. 9 μm while the maximum corrosion depths in WNZ on top surface and root surface are 46. 3 μm and 84. 1μm respectively.