Microstructural evolution and corrosion mechanism of Cu-Y alloys: The role of Cu ₆ Y precipitate phase

The microstructure and corrosion behavior of the Cu-Y alloys were investigated. It was found that with increasing Y content, Cu ₆ Y gradually precipitated in a network morphology along grain boundaries, resulting in a phase composition of α + Cu ₆ Y + (α+Cu ₆ Y) _eutectic . The alloy with an Y addition of approximately 0.08 wt.% exhibited the best corrosion resistance among all the studied samples. The flat and dense deposition layer was identified as key to inhibiting the continued corrosion of the Cu-Y alloy. The beneficial effect of Cu ₆ Y can be demonstrated that its preferential corrosion provided sacrificial anode-like protection for the entire sample, while the released Y ³⁺ participate in the formation of the passive film, thereby inhibiting the corrosion process.