Transactions of Nonferrous Metals Society of China (中国有色金属学报)•2026•DOI: 10.1016/S1003-6326(26)67058-6
Twin-roll casting (TRC) Mg−3Al−1Sn−0.5Ca−0.2Mn (ATXM) alloys exhibit limited deformation resistance and inadequate corrosion performance, constraining their commercial deployment. This study integrates rare earth (RE) microalloying (Sm, Ce, or Y at 0.1 wt.%) with rolling to address the strength–plasticity–corrosion trilemma. Rolling reduces grain size from ~50 μm to below 5 μm and transforms Al8Mn5 secondary phases into Al8Mn4RE, modifying phase composition, dimension, and spatial arrangement. The rolled ATXM-0.1Y alloy achieves a yield strength of 238 MPa, tensile strength of 305 MPa, and elongation of 23%, coupled with a corrosion rate of approximately 1.7 mm/a—an ~80% reduction relative to TRC ATXM. Sm and Ce additions yield strengths of 238 and 232 MPa, elongations of 18% and 17%, and corrosion rates of 3.4 and 2.9 mm/a, respectively. Strengthening mechanisms are attributed to fine-grain and Orowan strengthening, while corrosion mitigation arises from reduced individual galvanic corrosion and enhanced protective corrosion product film quality. The work establishes a screening protocol for RE elements and processing parameters to synergistically improve mechanical and corrosion properties, facilitating commercial adoption of Mg alloys.
China Foundry•2026•DOI: 10.1007/s41230-026-5146-x
Wire-arc directed energy deposition (WA-DED) has attracted considerable attention for the fabrication of magnesium (Mg) alloys due to its high efficiency, low cost, and rapid prototyping capability for complex components. However, the inherent rapid solidification and complex thermal cycling associated with WA-DED often result in coarse columnar grains and pronounced mechanical anisotropy, which severely limiting its application potential. In this study, a novel spiral oscillation (SO) strategy was implemented during WA-DED AZ31 Mg alloy to refine the microstructure, reduce mechanical anisotropy, and achieve a strength-ductility synergy. Specifically, the yield strength (YS), ultimate tensile strength (UTS), and elongation (EL) are increased by 9.7%, 38.1%, and 147%, respectively. These improvements by the SO strategy are primarily attributed to the promotion of columnar-to-equiaxed transformation (CET), a 74.2% reduction in maximum texture intensity, and a more uniform distribution of second-phase particles. Second-phase particles are primarily composed of Al8Mn5 and Al8Mn4Y. This study provides a novel strategy for microstructural control aimed at improving the performance of WA-DED AZ31 Mg alloy components.
Transactions of Nonferrous Metals Society of China (中国有色金属学报)•2025•DOI: 10.1016/S1003-6326(25)66952-4
The effects of artificial aging (T6) on the creep resistance with tensile stresses in the range of 50−80 MPa at 175 °C were investigated for an extruded Mg−1.22Al−0.31Ca−0.44Mn (wt.%) alloy. The Guinier-Preston (G.P.) zones primarily precipitate in the sample aged at 200 °C for 1 h (T6-200°C/1h), while the Al2Ca phases mainly precipitate in the sample aged at 275 °C for 8 h (T6-275°C/8h). The T6-200°C/1h sample exhibits excellent creep resistance, with a steady-state creep rate one order of magnitude lower than that of the T6-275°C/8h sample. The abnormally high stress exponent (~8.2) observed in the T6-200°C/1h sample is associated with the power-law breakdown mechanism. TEM analysis illuminates that the creep mechanism for the T6-200°C/1h sample is cross-slip between basal and prismatic dislocations, while the T6-275°C/8h sample exhibits a mixed mechanism of dislocation cross-slip and climb. Compared with the Al2Ca phase, the dense G.P. zones effectively impede dislocation climb and glide during the creep process, demonstrating superior creep resistance of the T6-200°C/1h sample.