Synthesis and molecular dynamics investigation of Mg/SiCP composites with high thermal conductivity and low expansion

• The potential application of cast SiC/Mg composites in thermal management has been reported for the first time. This material demonstrates excellent thermal conductivity (178.5 W/m·K) and a low coefficient of thermal expansion (16.8 × 10⁻⁶/K), along with the ability to form large-sized ingots with uniform composition. • An in-depth investigation into the heat transfer behavior at the Mg/SiC interface revealed that introducing a Cr interlayer significantly enhances the interfacial thermal conductance, offering valuable insights for future research. • Novel parameters and sampling methods for phonon coupling at interlayer interfaces were proposed to accurately characterize the influence of the interlayer on the heat transfer behavior of the original interface. The critical challenge of chip thermal dissipation fundamentally constrains both power consumption and operational longevity, underscoring the imperative demand for advanced packaging materials exhibiting superior thermal conductivity coupled with ultralow thermal expansion. Magnesium-based packaging systems demonstrate considerable promise in this strategic domain; however, current research efforts remain notably sparse, particularly regarding SiC particulate (SiC P )-reinforced magnesium matrix composites. In this investigation, we prepared SiC P -reinforced magnesium matrix composites through optimized stir casting methodology and systematically investigated their thermophysical characteristics. Remarkably, the composite incorporating merely 25 vol.% SiC P exhibited exceptional thermal performance metrics: a thermal conductivity of 178.5 W/(m·K) and a coefficient of thermal expansion as low as 16.8 × 10 −6 K −1 . Furthermore, molecular dynamics simulations were employed to elucidate thermal transport mechanisms at Mg/SiC interfaces, revealing that chromium interlayer implementation substantially enhances interfacial thermal conductance compared to direct bonding configurations. This comprehensive study not only validates the efficacy of SiC P reinforcement in optimizing magnesium matrix composites’ thermophysical properties but also establishes Mg/SiC P composites as a cost-competitive solution for next-generation thermal management applications.