@article{Li2026, 
author = {Bing Li and Xinpeng Li and Meng Zhang and Xingkang Zheng and Yujie Wang and Zhaoming Yan and Changcai Zhao},
title = {Insight into the evolution of lamellar and block LPSO phase of Mg-Gd-Y-Zn-Zr alloy with laser welding after post-weld solution and aging treatment},
year = {2026},
journal = {Journal of Magnesium and Alloys},
volume = {16},
number = {C},
keywords = {Aging treatment, Laser welding, LPSO phase, Post-weld solution treatment},
url = {https://www.sciopen.com/article/10.1016/j.jma.2025.09.003},
doi = {10.1016/j.jma.2025.09.003},
abstract = {The paper systematically investigated the effect of laser welding parameters and post-weld heat treatment on morphology microstructure evolution and mechanical properties of weld joint of Mg-13Gd-4Y-2Zn-0.6Zr alloy consisting of lamellar and block long-period stacking ordered (LPSO) phases. Experimental results demonstrate that laser power and welding speed significantly influence weld geometry, with optimal parameters (600 W, 25 mm/s) achieving full penetration, stable keyhole dynamics, and minimal defects, while resulting in a narrow heat-affected zone (HAZ)(<100 µm) dominated by fine grains. The eutectic (Mg,Zn)3(Gd,Y) phase formed at fusion zone (FZ) and HAZ after laser welding, which was attributed to remelting process during laser welding. Furthermore, the post-weld solution and aging treatments were conducted on Mg-Gd-Y-Zn-Zr alloy with laser welding. The rare earth (RE) atoms from eutectic (Mg,Zn)3(Gd,Y) phases and block LPSO phases dissolved into α-Mg grains in the course of solution treatment, thus lamellar 14H-LPSO phase precipitated from grain boundaries into α-Mg grains along basal planes and equilibrium β phases precipitated at grain boundaries with reduced block LPSO. The lamellar 14H-LPSO phase precipitated across α-Mg grains as solution time further increased, and only the equilibrium β phase remained at grain boundaries. The finely dispersed β′ phase precipitated inside α-Mg grains after aging treatment, thus nano-sized and densely β′ phase contributed to dislocation pinning, which significantly improves microhardness. The ellipsoidal β′ phases precipitated perpendicular to 14H-LPSO lamellae within the α-Mg grains consisting of lamellar 14H-LPSO phase. However, the β′ phases precipitated in three directions with an angle of 120° to each other within α-Mg grain that is devoid of 14H-LPSO lamellae. The equilibrium β phases gradually declined with prolonged aging treatment. The precipitation of lamellar 14H-LPSO and nano-sized β′ phase contributed to grain boundary migration of α-Mg grains. The results provide fundamental principle for optimizing weld integrity and mechanical response in Mg-RE-Zn alloys with LPSO phase.}
}