Towards development of a high-strength stainless Mg alloy with Al-assisted growth of passive film.

Zhu, Qingchun; Li, Yangxin; Cao, Fuyong; Qiu, Dong; Yang, Yao; Wang, Jingya; Zhang, Huan; Ying, Tao et al. · Nat Commun · 2022

basic_science · Level V

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Abstract

Magnesium alloys with high strength and excellent corrosion resistance are always sought-after in light-weighting structural components for automotive and aerospace applications. However, for most magnesium alloys that have a high specific strength, they usually have an inferior corrosion resistance and vice versa. In this work, we successfully develop a Mg-11Y-1Al (wt. %) alloy through conventional casting, solution treatment followed by extrusion. The overall properties of this alloy feature with a corrosion rate lower than 0.2 mm y<sup>-1</sup>, high yield strength of 350 MPa and moderate tensile elongation of 8%, the combination of which shows competitive advantage over other comparative magnesium alloys in the literature. It is found that a thin and dense protective film of Y<sub>2</sub>O<sub>3</sub>/Y(OH)<sub>3</sub> can be fast developed with the aid of Al<sub>2</sub>O<sub>3</sub>/Al(OH)<sub>3</sub> deposition to isolate this alloy from further attack of corrosion medium. Meanwhile, the refined grains, weak texture and activation of non-basal slip systems co-contribute to the high strength and good ductility. Our findings are expected to inspire the design of next-generation high performance magnesium alloys.