Mechanical behaviors and precipitation transformation of the lightweight high-Zn-content Al–Zn–Li–Mg–Cu alloy

Abstract

Designing high-performance Al-based alloys based on the entropy concept offers a promising strategy for next-generation advanced structural materials. The main idea of entropy increasing is to increase the content of alloying elements. For traditional high-strength Al–Zn–Mg–Cu alloy, however, significantly increasing the content of alloying elements, especially when the Zn content is increased to above 10 at.% (atomic percent), leads to poor deformability and poor tensile property. Here, we overcome this trend by designing a quinary alloy based on the idea of high-entropy alloys. We fabricate a high-Zn-content Al80Zn14Li2Mg2Cu2 alloy with the Zn content above 10 at.%. It shows Zn, and Al–Zn precipitates in the as-cast state, and it is observed that Al3(Li, Mg), MgZn2, and Zn nano-precipitates form after rolling. The precipitation transformation contributes to high strength and high deformability. Our present findings provide not only a fundamental understanding of precipitation transformation in the high-Zn-content Al alloys but valuable guidance for the development of lightweight alloys as well.