Microstructure and Anisotropy of Mechanical Properties of Al-3Li-1Cu-0.4Mg-0.1Er-0.1Zr Alloys Prepared by Normal Rolling and Cross-Rolling

Abstract

The influence of normal rolling and cross-rolling on the microstructure, mechanical properties, and anisotropy of Al-3Li-1Cu-0.4Mg-0.1Er-0.1Zr alloy was investigated. With an increase in the rolling reduction amount, both the strength and plasticity of the alloy are enhanced. Among them, the alloy in the normal rolling state with a deformation amount of 90% exhibits the best properties, with a tensile strength of 362 MPa and an elongation of 19.1% along the rolling direction. During the rolling process, the intergranular Cu-containing phase in the alloy is continuously broken and dissolved, leading to a decrease in both size and quantity, turning from continuous distribution along grain boundaries to a granular distribution. Moreover, a large quantity of the Al3Li phase and Al3(Er, Zr, Li) core–shell composite phase are precipitated in the alloy. Recrystallization occurs mainly through the particle stimulated nucleation (PSN) mechanism. Cross-rolling eliminates the brass-type texture <111> produced by normal rolling and enhances the brass R-type texture {111}<112>. The index of plane anisotropy (IPA) of the strength decreases from 10.1% for normal rolling to 5.5% for cross-rolling, and the IPA of elongation decreases from 12.8% to 3.3%. Cross-rolling provides an effective method to reduce the anisotropy of Al-Li alloys.