Improvement of thermal properties of Al/Cu/SiC composites by tailoring the reinforcement microstructure and comparison to thermoelastic models.

In the current investigation, Al/Cu/SiC composites with different reinforcement contents were prepared for thermal applications via powder metallurgy and hot pressing technique to study the effects of reinforcement content and structure on the thermal behavior of the samples. Microstructural characterizations showed that SiC and Cu particles were uniformly distributed, and a continuous Cu network structure was formed in the Al matrix. Density measurements revealed that the samples Al/15Cu/10SiC and Al/45Cu/20SiC had the highest and lowest relative density (97% and 90%), respectively. Microhardness evaluations displayed that the composite hardness improved as the Cu and/or SiC contents increased. Besides, the coefficient of thermal expansion of the composites increased nonlinearly by elevating the temperature and it reduced with increasing the SiC content. A comparison of thermal expansion coefficient values to the Turner and Kerner models showed a slight difference (lower that 8%) only for Al/15Cu/10SiC and Al/45Cu/20SiC samples. Thermal cycles examination exhibited that as the number of cycles increased, the thermal strain of the composites increased. Furthermore, the thermal expansion coefficient of Al/45Cu/20SiC reduced to values lower than 7 ppm that indicates the significance of Cu network structure. Image 1 • Al/Cu/SiC composites were prepared for thermal applications by powder metallurgy. • SiC particles were uniformly distributed and a continuous Cu network was obtained. • A comparison of CTE values to the thermoelastic models showed a slight difference. • CTE values lower than 7 ppm indicated the efficiency of reinforcement structure. [ABSTRACT FROM AUTHOR]