Galvanic corrosion behavior of friction stir welded AZ31B magnesium alloy and 6N01 aluminum alloy dissimilar joints

摘要

The corrosion behavior and corrosion rate of friction stir welded AZ31B magnesium alloy and 6N01 aluminum alloy dissimilar joints were studied using real-time imaging, potentiodynamic polarization, EIS, and hydrogen evolution tests. The corrosion rate was found to increase, in order, Al base metal (BM-6N01) Mg base metal (BM-AZ31B) stirred zone. The galvanic coupling of the Mg phase to the other phases enhanced the corrosion of both BM-AZ31B and BM-6N01. Accompanying the intense corrosion at BM-AZ31B, water reduction on the cathodic particles of BM-6N01 elevated the interfacial pH to a level where the Al matrix corroded to AlO2-.