Enhanced mechanical properties of Mg-1Al-12Y alloy containing long period stacking ordered phase

In this study, a systematic investigation on the effect of solution treatment time (2-8 h) at 540 degrees C on the microstructure and mechanical properties in as-cast Mg-1Al-12Y (AY112, wt.%) alloy was performed. The results showed that the solution treatment did not cause the growth of grains and the change of texture; however, the mechanical properties had been significantly improved, which was mainly attributed to the precipitation of 18R long period ordered stacking (LPSO) phase in the solution-treated alloys. In addition, the dissolution of beta-Mg24Y5 phase and the diffusion of solute atoms during the solution treatment were both beneficial to the mechanical properties. When the as-cast alloy was solution-treated at 540 degrees C for 4 h (T4-4h alloy), the mechanical properties of the alloy are optimal. Compared with the as-cast alloy, the ultimate tensile strength (UTS) and elongation of the T4-4h alloy are increased by similar to 23% and similar to 179%, respectively. The deformation of the T4-4h alloys was dominated by a combination of basal a> slip and non-basal <a> slip, and the presence of the LPSO phase effectively inhibited the nucleation of extension twin. Besides, the LPSO phase can also hinder the activation of basal <a> dislocations and the movement of non-basal a> dislocations. Therefore, the LPSO phase simultaneously improves the strength and plasticity of the alloy. (c) 2022 Chongqing University. Publishing services provided by Elsevier B.V.