Exceptional thermal conductivity and superior modulus of magnesium alloys via carbon fiber incorporation

Magnesium (Mg) alloys as the lightest metallic structural materials are strongly embraced in 3C products and 5G communications. Yet, their unsatisfactory thermal conductivity and stiffness fail to meet the progressively stringent demands for thermal management and extreme thinness. Herein, the Mg matrix composites with diverse volume fractions of the carbon fiber (CF) were fabricated by the differential speed stir casting followed by hot extrusion. The exceptional thermal conductivity (163.8 W/(m center dot K), surpassing pure Mg) and superior modulus (55.8 GPa) were realized with 14 vol% CF. The thermal conductivity and modulus were elevated to 188.3 % and 126.5 % of the respective values for AZ31 Mg alloys commonly employed in 3C structural components. The heatconduction behaviors were scrutinized utilizing the scanning thermal microscopy (SThM) and actual microstructural finite element (FE) simulations. The pronounced microscale temperature differential between the CF (60.3 degrees C) and Mg matrix (65.6 degrees C) demonstrated that the CF can effectively ameliorate the thermal conductivity of the Mg matrix. This improvement was realized by constructing the most efficient pathway for heat flux. The inherent high modulus of the CF (205.3 GPa) contributed to the enhancement in the modulus of the Mg matrix. Thermal mismatch, grain refinement, and load transfer strengthening mechanisms co-contributed to the enhancement in yield strength. This work bridges the exceptional thermal conductivity and superior modulus of Mg matrix composites, paving the way for modern high-performance smart terminals and communication devices.