LD10铝合金搅拌摩擦焊接头的腐蚀特性

Corrosion performance of friction stir welding joint of LD10 aluminum alloy

利用搅拌摩擦技术对LD10铝合金板材进行焊接,观察了搅拌摩擦焊接头搅拌区、热机械影响区、热影响区及母材区的微观组织。通过浸泡试验、盐雾腐蚀试验、动电位极化和电化学阻抗谱评估了接头的腐蚀特性,分析了LD10铝合金搅拌摩擦焊接头腐蚀机理。发现搅拌摩擦焊接头区域的开路电位高于母材区,同时腐蚀电流密度小于母材区,且接头区域的容抗弧半径比母材区更大。LD10铝合金搅拌摩擦焊焊接接头耐蚀性好于铝合金母材,这同搅拌区晶粒细小和Cu Al2析出相分布均匀有关。

LD10 aluminum alloy was welded using friction stir welding( FSW) technique. Microstructure of the stir zone( SZ),thermomechanically affected zone( TMAZ),heat affected zone( HAZ) and the base metal( BM) of the FSW joint was observed. The corrosion performance of the FSW joint was evaluated by the immersion test,salt spray test,potentiodynamic polarization and electrochemical impedance spectroscopy. The corrosion mechanism of FSW joint of LD10 alloy was analyzed. The results show that,the FSW joint of LD10 alloy has higher open circuit potential,lower corrosion current density and higher impedance comparing to the LD10 base metal,thus the corrosion resistance of FSW joint of the LD10 alloy is higher than that of LD10 base metal,which is ascribed to the fine grain and uniform distribution of Cu Al2 precipitated phase in stir zone of the alloy.