The design of high-strength and high-thermal-conductivity magnesium alloy sheets is challenged by the inherent contradiction between strength and thermal conductivity, as well as the complex variables involved in the rolling process. In this study, Mg-xZn-0.5Gd-0.5Y (at.%) (1/x = 0.5, 1.0, 1.5) alloys were developed by adjusting the atomic ratio of rare earth (RE) elements to Zn. In the subsequent multi-pass hot rolling process, the influence of various factors on the microstructure and comprehensive properties of alloys with different compositions was obtained. With the decrease of RE/Zn atomic ratio, the W phase gradually dominates, which ensures the high thermal conductivity throughout the preparation process. Additionally, the thickness reduction per pass plays a decisive role in the properties of alloys by affecting the precipitates, dislocations and grains. The reheating between passes plays a coordinating role in the whole rolling process through the twin-induced static recrystallization mechanism. The findings indicate that leveraging the advantages of large thickness reduction per pass and effectively coordinating strain accumulation is a viable strategy for progressively enhancing the strength of high-thermal-conductivity magnesium alloys, ultimately leading to superior comprehensive performance. This study provides systematic research results for the composition design and process optimization of high-strength and high-thermal-conductivity magnesium alloy rolled sheets, which is helpful to promote the performance breakthrough and application expansion in this field.

This study elucidates the non-thermal mechanism of dislocation density reduction in a Mg-Y-Nd-Gd-Zr alloy under continuous electropulsing (6.67–15 A/mm²) at ultra-low temperatures (−150 °C to −196 °C) through tripartite characterization and first-principles analysis. Electron backscatter diffraction (EBSD) reveals a 15.2 % decrease in geometrically necessary dislocation (GND) density with increasing current, while X-ray line profile analysis (XLPA) confirms the inverse correlation between current intensity and overall defect density. Transmission electron microscopy (TEM) directly visualizes the dissolution of entangled dislocation clusters into isolated lines under high-current treatment (15 A/mm²), corroborating the statistical trends. First-principles calculations demonstrate that localized charge accumulation at defect sites reduces Mg vacancy formation energy by up to 2.8 %, lowering lattice resistance to dislocation glide. This charge-state-dependent vacancy proliferation provides a mechanistic link between electron flow and dislocation annihilation. The reduction of vacancy formation energy is a significant factor in the electron-induced dislocation evolution effect at ultra-low temperatures. These findings provide direct evidence for electron-induced dislocation annihilation mechanisms independent of Joule heating, advancing the understanding of electroplasticity in hexagonal close-packed alloys, and providing a novel approach for rapid, non-oxidative microstructural and property tuning of magnesium alloys.

The addition of effective nucleating particles in the melt to achieve grain refinement has become the most widely used method for the casting industries. In this study, a novel GNP@MgO particle with a nanocomposite structure was prepared by utilizing an in-situ reaction of the carbon source gas with Mg melt. The results showed that the particles can significantly reduce the average grain size of Mg-9Al alloy from 130.4 µm to 13.1 µm, and achieve an ultra-high grain refinement efficiency of 90%. The refinement mechanisms are that the Al₄C₃ phase can act as a heterogeneous nucleation site for α-Mg grains due to the orientation relationship as (001)_Al4C3//(002)_Mg. Meanwhile, the particle distribution model shows that the velocity of MgO particles is much higher than the growth rate of α-Mg grains. Therefore, it is pushed to the vicinity of grain boundaries during solidification, effectively limiting the growth of α-Mg grains. The remarkable grain refinement effect was achieved through the synergistic modulation of Al₄C₃ and MgO particles. This work may provide new insight into designing high efficiency grain refiners for Mg-Al alloys.

Converting CO₂ to valuable materials is attractive in environmental protection and resource utilization. In this study, a vapor–liquid interface reaction system for mass production of high-quality graphene is reported. The graphene obtained has high crystallinity and few defects during the reaction of CO₂ and Mg melt. The growth mechanism of graphene is demonstrated in vapor–liquid interface area by combining the CO₂ bubbles as a soft template to guide growth with the confinement effect of dense MgO nanoparticles. The quality of the graphene is verified by epoxy composites with high electromagnetic shielding effectiveness. Additionally, the V–L reaction method ingeniously solves the dispersion of graphene in metal, providing a preparation strategy of Mg matrix composites with structure and function integration.