Focusing on the relationship between the precipitated phases and the pitting corrosion of ZL101A aluminum alloy

The pitting corrosion behavior of ZL101A aluminum alloy in simulated marine environment was investigated for guiding the composition design. The Volta potential of the precipitated phases was mainly characterized via the in situ SKPFM technique. The obtained results indicated that the precipitated phases of ZL101A were composed of Al-Si phase, Si-Mg-Fe phase and Si-rich/Al-poor phase, accelerating the formation of corrosion pits during immersion test. Both Al-Si phase and Si-Mg-Fe phase accelerated the corrosion process through the self-dissolution and the galvanic effect, respectively, which can be contributed to the high corrosion sensitivity of the two phases. Si-rich/Al-poor phase presented high corrosion resistance, which should be related to the deficiency of impure elements such as Mg and Fe.