Effects of Beryllium Addition on Microstructure, Mechanical and Corrosion Performance of Al-Mg-Li Alloys

Abstract

The Al-Mg-Li alloy is ideal for ultra-lightweight aircraft components, and its further performance improvement is of great interest in the aerospace industry. In this study, the effects of various beryllium (Be) additions (Be-free, 0.1, 0.25, 0.50 wt.%) on the microstructure, mechanical, and corrosion performance of the Al-Mg-Li alloys were systematically investigated. The optimal tensile property was obtained in the alloy which added 0.1 wt.% Be with an ultimate tensile strength (UTS), yield strength (YS), and elongation (El) of 530 MPa, 370 MPa, and 9.2%, respectively. Trace Be addition promotes the grain refinement of the as-cast alloy ingot and contributes positive effects to the recrystallization, bringing improvement of the tensile property. Meanwhile, the best anti-corrosion behavior is also presented at 0.1 wt.% Be is added, due to its potential to reduce the width of precipitates free zone (PFZ). As the Be content increases to an excessive level, the comprehensive performance decreases. Therefore, it is strongly recommended that adding trace Be elements into Al-Mg-Li alloys has a positive effect on the comprehensive service performance.