The effect of alloying element on the thermophysical properties of carbon fiber-graphite flakes/copper composites

In this study, carbon fiber-graphite flake/copper composites were prepared by powder metallurgy. The impact of the alloying elements Ti and Zr on the composites’ properties was investigated, and the influence of varying Zr contents on the phase structure and thermal conductivity of the composites was also explored. The results indicate that composites containing Zr exhibit better flexural strength and thermal conductivity compared to those containing Ti. When the volume fraction of carbon fiber is 2% and 2 wt% Zr is added to copper matrix, the carbide layer at the composite interface is uniform and has a thickness of 0.36 μm. The thermal conductivity of the composite material is up to 597.5 W/(m∙K). The mechanical properties of the composites are enhanced by the synergistic effect of adding carbon fiber and alloying matrix and the composite shows a remarkable flexural strength of 150.5 MPa, which is 58.3% higher compared to composites without carbon fiber. Furthermore, the strengthening mechanism of carbon fiber on the mechanical properties of the composites was examined. The thermal conductivity of the multiphase composites was effectively predicted using the Acoustic Mismatch Model (AMM) combined with the MF module of Digimat software, and the impact of Ti or Zr elements on the composites’ thermal conductivity was analyzed.