异种铝合金搅拌摩擦焊与MIG焊焊缝的腐蚀性能对比

Comparsison of corrosion properties for aluminum alloy friction stir welding and metal inert-gas welding dissimilar weld

在室温0.2 mol/L NaHSO3+0.6 mol/L NaCl溶液中,通过动电位极化曲线测试,电化学阻抗谱(EIS)试验,静态失重试验,对铝合金搅拌摩擦焊(FSW)和MIG异种焊缝的腐蚀性能进行了对比。结果表明:FSW异种焊缝与MIG异种焊缝、两种母材相比,腐蚀电位Ecorr最大,腐蚀电流密度和平均腐蚀速率最小,极化电阻Rp最大。同时使用扫描电子显微镜(SEM)对失重后试样的表面形貌进行了观察,发现FSW异种焊缝表面平坦均一,而MIG异种焊缝表面比较粗糙。

In the ambient temperature 0. 2M NaHSO3 and 0. 6M NaCl solution,the corrosion properties for 5083 and 6082 aluminum alloy friction stir welding and metal inert - gas welding dissimilar weld were comparatively investigated by potentiodynamic polarization curve ,electrochemical impedance spectroscopy（EIS）and static weight loss experiment. The corrosion potentials of the FSW dissimilar weld were more positive than those of MIG dissimilar weld,meanwhile,the corrosion rate and the corrosion current density were less than those of MIG dissimilar weld and parent metals,Rp（polarization resistance）of the FSW dissimilar weld was larger than that of MIG dissimilar weld and parent metals. Scanning electron microscope（SEM）observation showed that a few shallow pits presented on the surface of the FSW dissimilar weld,however,a large number of deeper pits emerged on the surfaces of MIG dissimilar weld.