Fabrication, microstructure, and thermal conductivity of multilayered Cu mesh/AZ31 Mg foil composites

Abstract

In this study, multilayered Cu mesh/AZ31 Mg foil composites were designed and fabricated by diffusion bonding in a closed graphite mold at 400–445 °C. The effects of temperature on the microstructure of the joints formed and the thermal conductivity of the composite was evaluated. The mechanism responsible for the observed improvement in thermal conductivity was analyzed. After diffusion bonding, the thermal conductivity of the multilayered composite was as high as 122.3 W/m·K at room temperature (25 °C), which is 109.4% higher than that of the AZ31 Mg alloy (58.4 W/m·K) fabricated using the same process. Moreover, the fabricated Mg matrix composites had a maximum density of 2.21 g/cm3, indicating that they were lightweight. A continuous film-like structure composed of intermetallic compounds and α-Mg region with good contribution to heat conduction has been found, which has a reference for the design and fabrication of high-thermal-conductivity Mg matrix composites.

Keywords

• Mg-based composites
• Cu mesh
• Microstructure
• Thermal conductivity
• Diffusion bonding