Copper–graphite composites: Cross-property connections between electrical conductivity and thermal expansion coefficient for 0–90 vol% of graphite

Abstract

This paper focuses on the electrical conductivity and thermal expansion coefficient of copper–graphite composites in the range of 50–90 vol.% graphite. In the previous authors’ work, elastic and conductive properties for the range of 0–50 vol% graphite were studied and cross-property connections were established between (1) electrical and thermal conductivities and thermal expansion coefficient and (2) electrical resistivity and shear modulus. Copper–graphite composites are prepared using hot isostatic pressing from the mixture of copper and graphite powders. The microstructure of the composites consists of copper particles that are homogeneously distributed within the dominant graphite phase (50–90 vol% graphite). The density, electrical conductivity, and thermal expansion coefficients of copper–graphite composites for the range of 0–90 vol% graphite are measured. Cross-property connections between electrical resistivity and thermal expansion coefficients are modeled using various techniques of micromechanics that account for the volume fraction, shape, size, and orientation of composites’ constituents. Cross-property connections between the said properties are verified using the obtained experimental data.