Microhardness and Texture Evolution of Ultralight Mg-Li Alloy Processed by Cold Rolling

Single beta-type Mg-12Li and Mg-12Li-1Al (wt %) alloy sheets were prepared by casting, followed by cold rolling. Microstructure and texture analysis were carried out on the alloy samples using optical microscopy, scanning electron microscope, X-ray diffractometry, and microhardness testing. The results indicated that cold-rolled alloys exhibited elongated grains in rolling direction with many slip lines and deformation bands. No recrystallization was observed during the whole cold rolling process. The microhardness was from 40 to 55 HV for Mg-12Li and 60 to 85 HV for Mg-12Li-1Al, indicating that the aluminum (Al) addition improved the strain hardening of Mg-12Li. Texture evolution analysis revealed that (111) [110] was the preferred orientation during deformation in both alloys, while the addition of Al in the as-cast Mg-12Li not only lowered the {200} pole figure intensity but also occupied the (111) [110] orientation in the alpha and gamma fiber maps.