Isolating intermediate Mg11Cu6Al12 phase in ternary Mg-Cu-Al alloy by electrolytic dealloying

While dealloying is widely used to create nanoporous materials, it has rarely been employed to isolate difficult-to-synthesize intermediate phases. Here we show how air-free, electrolytic dealloying at room temperature can be used to isolate the ternary intermetallic Mg11Cu6Al12 phase. We create a ternary Mg-Cu-Al parent alloy containing the Mg11Cu6Al12 compound and other phases, then subsequently remove these other phases via electrolytic dealloying to isolate the Mg11Cu6Al12 phase. Isolated Mg11Cu6Al12 phase exhibits ≈1 μm diameter rod-shaped microstructure. Phase and chemical analysis conducted using various techniques, including inductively coupled plasma and lab and synchrotron-based X-ray diffraction, show minimal impurities. This new approach to isolate the Mg11Cu6Al12 phase can unlock its use in fundamental research and can be applied to other difficult-to-synthesize intermetallic compounds.