Development of highly corrosion-resistant Mg-Al-Y extruded alloy via regulating the Mg17Al12 phase

A highly corrosion-resistant AW90 extruded alloy (Mg-9Al-0.2Y wt.%) was developed via alloying and solution-aging treatment (PW = 0.14 mm/y). The solution-treated AW90 alloy exhibits the most severe localized corrosion due to the strong micro-galvanic acceleration effects. The finely dispersed Mg17Al12 phase promotes the strong quasi-passive behavior and uniform corrosion of the aged AW90 alloy due to the formation of a dense and uniform corrosion product film. The high corrosion resistance of the aged AW90 alloy is attributed to the formation of a Mg-Al layered double hydroxide film, which has stronger resistance to chloride ions.