As highly integrated circuits continue to advance, accompanied by a growing demand for energy efficiency and weight reduction, materials are confronted with mounting challenges pertaining to thermal conductivity and lightweight properties. By virtue of numerous intrinsic mechanisms, as a result, the thermal conductivity and mechanical properties of the Mg alloys are often inversely related, which becomes a bottleneck limiting the application of Mg alloys. Based on several effective modification methods to improve the thermal conductivity of Mg alloys, this paper describes the law of how they affect the mechanical properties, and clearly indicates that peak aging treatment is one of the best ways to simultaneously enhance an alloy's thermal conductivity and mechanical properties. As the most frequently used Mg alloy, cast alloys exhibit substantial potential for achieving high thermal conductivity. Moreover, recent reports indicate that hot deformation can significantly improve the mechanical properties while maintaining, and potentially slightly enhancing, the alloy's thermal conductivity. This presents a meaningful way to develop Mg alloys for applications in the field of small-volume heat dissipation components that require high strength. This comprehensive review begins by outlining standard testing and prediction methods, followed by the theoretical models used to predict thermal conductivity, and then explores the primary influencing factors affecting thermal conductivity. The review summarizes the current development status of Mg alloys, focusing on the quest for alloys that offer both high thermal conductivity and high strength. It concludes by providing insights into forthcoming prospects and challenges within this field.

An ultra-high strength and toughness as-cast Mg-10Gd-1.7Y-1Zn-0.5Zr (wt.%) alloy was prepared via special ultrasonic melt treatment, and the peak-aged (200 ℃ for 48 h) ultimate tensile strength (UTS), yield strength (YS) and elongation (EL) at room temperature reaches 430 MPa, 324 MPa, and 13.6%, respectively. The ultrasonic treatment during semi-solid conditions refines the grains and hinders the growth of the divorced eutectic phases (α-Mg + Mg₃Gd) during casting. During the solution treatment, the refined Mg₃Gd phase suppresses the formation of cubic-shaped GdY phases and block 14H long period stacking structure (14H-LPSO) phases, and further increases solute concentration in the matrix. More solute atoms promote the growth of β’ plates with an increased aspect ratio of 8:1, which can increase critical resolved shear stress (CRSS), YS and work hardening rate. It is that found the aspect ratio of β’ plates are mainly responsible for the improvement in the strength of the alloy under the same composition and heat treatment conditions.

Since the introduction of Tesla’s Giga-Casting process, the automotive industry has widely accepted the concept of super-sized structural components due to their significant potential for enhancing the light-weighting of both electric and internal combustion engine vehicles. These super-sized components can be further lightened by using Mg alloys because of their exceptional lightweight characteristics, with a density only two-thirds that of aluminium alloys and one-fourth that of steel. This outstanding attribute offers the attractive prospect of achieving significant weight reduction without compromising structural integrity. This review examines studies on the Mg-alloy High-Pressure Die Casting (HPDC) process, providing insights into the future prospects of incorporating Mg alloys into super-sized automotive HPDC components.

Designing and developing the Mg alloys with low cost and high performance is of the great significance. Novel Mg-1Bi-xMn (x = 0, 1 and 2 wt.%) extruded alloys, in this work, were fabricated at different extrusion temperatures (220, 250 and 300 ℃). The effects of extrusion temperature and Mn addition on the microstructures and mechanical properties of extruded alloys at room temperature were investigated. The results showed that decreasing the extrusion temperature could refine the average grain size, weaken the basal fiber texture intensity and improve the microstructural homogeneity of extruded alloys. When the Mn element was added to the Mg-1Bi alloy, the average grain size further reduced. Simultaneously, the number fraction of low angle grain boundaries (LAGBs) increased, along with the occurrence of regions without dynamic recrystallization (unDRX). The combined effects of grain refinement and coarse unDRXed structure made the textures of the extruded Mg-1Bi-xMn alloys never obviously change. Besides few large size un-dissolved second phases, fine Mg₃Bi₂ and α-Mn phases were precipitated in the extruded Mg-1Bi-xMn alloys and partial nano-scale α-Mn particles pined at grain boundaries (GBs) to effectively impede the migration of GBs for grain refinement. Microstructural variations determined the extruded Mg-1Bi-2Mn alloy to exhibit the highest yield strength of ~ 319.2 MPa with the appropriate elongation-to-failure of ~ 13% at the extrusion temperature of 220 ℃, and they enabled the extruded Mg-1Bi-1Mn alloy to show the highest elongation-to-failure of ~ 26% without the obvious loss of yield strength of ~ 252.1 MPa.