Towards development of a high-strength stainless Mg alloy with Al-assisted growth of passive film
Qingchun Zhu, Yangxin Li, Fuyong Cao, Dong Qiu, Yao Yang, Jingya Wang, Huan Zhang, Tao Ying, Wenjiang Ding, Xiaoqin Zeng
Abstract
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 −1 , 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 2 O 3 /Y(OH) 3 can be fast developed with the aid of Al 2 O 3 /Al(OH) 3 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.