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采用剥蚀试验和动电位极化曲线测试对2219铝合金母材、搅拌摩擦焊(FSW)和钨极氩弧焊(TIG)焊接头的腐蚀行为进行了研究。通过腐蚀失重测试、电化学试验与剥蚀后表面及深度方向腐蚀微观形貌观察,对三者的腐蚀形式和机理进行了分析。结果表明:母材腐蚀速率最大,自腐蚀电位最低,而腐蚀电流密度最大;两种接头焊缝/焊核的耐蚀性总体接近,都优于母材的,FSW焊核的耐蚀性最优。合金母材的腐蚀形式为层状剥蚀,TIG焊缝为晶间腐蚀,深度较小,FSW焊核为点蚀。三者的腐蚀均与析出相有关,母材的析出相粗大,与基体之间的电偶效应最明显;TIG焊缝析出相沿枝晶晶界排列,但析出相尺寸小,电偶作用弱于母材;FSW焊核析出相尺寸由于机械搅拌而变小且分布弥散,腐蚀性能有所改善。
The corrosion behavior of 2219 aluminum alloy base metal, FSW and TIG welded joints was studied by using the erosion test and the potentiodynamic polarization curve test. The corrosion morphology and mechanism of the three were analyzed by corrosion weightlessness test, electrochemical test and corrosion micro-morphology observation of surface and depth direction. The results showed that the corrosion rate of the base metal was the highest, the corrosion potential was the lowest, and the corrosion current density was the highest. The corrosion resistance of the two joints was close to that of the base metal, and the corrosion resistance of the FSW excellent. The corrosion pattern of alloy base metal is lamellar denudation, the TIG weld is intercrystalline corrosion, the depth is small, and the FSW weld core is pitting corrosion. The corrosion of the three is related to the precipitation phase, the precipitation of the base metal coarse, the most obvious galvanic effect between the matrix; TIG weld precipitation phase along the dendrite grain boundaries, but the precipitated phase size is small, the role of galvanic weak Base metal; FSW weld nuclei precipitated phase size due to mechanical stirring and smaller distribution and dispersion, corrosion performance improved.