载荷作用下5A06铝合金焊接试样的腐蚀敏感性

Aimed at the aluminum alloy welding effect on corrosion sensitivity, we have applied loading on the 5A06 aluminum alloy with the welds in different directions (vertical, cross) and studied the effects of stress loading on the corrosion behavior of the alloy in 3.5%NaCl solution at 50℃ and the electrochemical corrosion behavior of the welded joints. The results show that after being soaked for 110 days in brine solution, heat-affected zone is firstly corroded and both sides of the corrosion pits on the surface exhibited step and dimple features respectively, because of the different material structure. The stress corrosion sensitivity of the cross weld specimen is relatively low and the stress concentration exists at the corrosion pit tip with a sliding step. Vertical weld specimen has higher sensitivity to stress corrosion with the corrosion pits across the surface along the weld. Both sides of the corrosion pits on the vertical weld specimen tear parallelly. The electrochemical polarization curves indicate that the corrosion potential of the heat-affected zone, base-metal zone and weld zone are -1.369 V, -0.791 V and -0.740 V, respectively.