@article{Wang2026, 
author = {Hui Wang and Gang Zeng and Chengwei Zhou and Yidi Li and Biaobiao Yang and Ruilin Lai and Chenying Shi and Dikai Guan and Hao Wang and Yujie Cui and Yunping Li},
title = {Heat treatment effects on microstructure, deformation mechanisms and mechanical response in additive friction stir deposited Mg-Gd-Y-Zr alloy},
year = {2026},
journal = {Journal of Magnesium and Alloys},
volume = {17},
number = {C},
keywords = {Additive friction stir deposition, Mg-rare earth alloy, Heat treatment, Microstructure, Mechanical properties},
url = {https://www.sciopen.com/article/10.1016/j.jma.2026.102019},
doi = {10.1016/j.jma.2026.102019},
abstract = {Additive friction stir deposition (AFSD), as a solid-state-additive manufacturing technique with a high deposition rate, provides an innovative route for fabricating high-performance magnesium (Mg) alloys while avoiding solidification defects. In this study, the effects of T6 heat treatment on the microstructure, mechanical properties, and deformation mechanisms of an AFSD Mg-9Gd-3Y-0.5Zr (wt.%) alloy were systematically investigated. The AFSD alloy exhibited a heterogeneous onion-ring microstructure composed of alternating fine grains (~3.9 µm) enriched with nanoscale cuboid Mg24(Gd, Y)5 precipitates and coarse grains (~10.6 µm) containing limited precipitates, which originated from the non-uniform precipitate distribution in the feedstock. The T6 heat treatment eliminated dislocation structures, introduced abundant nano-Mg7(Gd, Y) (β′) precipitates and coarsened the fine and coarse grains to ~7.3 and ~67.4 µm, respectively. Consequently, the AFSD and AFSD-T6 alloys achieved superior strength-ductility combinations compared to the feedstock, with yield strength/ultimate tensile strength/elongation of 293.5 MPa/330.3 MPa/8.1% and 366.8 MPa/374.3 MPa/5.1%, respectively. The heterogeneous grains induced pronounced hetero-deformation-induced hardening in both conditions, while basal 〈a〉 slip activity was progressively enhanced during deformation. However, extensive twinning, particularly double twinning in the coarse grains of the AFSD-T6 alloy, led to reduced ductility. Overall, this work demonstrates that coupling AFSD with tailored heat treatment enables effective microstructural heterogeneity engineering, offering a robust strategy for developing Mg-Gd-Y-Zr alloys with outstanding mechanical performance.}
}