Microstructural and mechanical characteristics of hybrid SiC/Cu composites with nano- and micro-sized SiC particles

Abstract

Hybrid Cu-SiC composites have been highly considered in order to achieve a combination of electrical and thermal properties along with high strength and wear resistance. However, limited investigations have ever been conducted over the effects of using hybrid (combination of nano and micro size) particles on the wear resistance behavior of these composites. Hence, in the present study, Cu-SiC nanocomposite with 4 vol% nanosize and 4 vol% microsize SiC, and Cu-SiC microcomposite with 8 vol% micro- SiC were fabricated through mechanical milling and hot pressing process. Results revealed the homogeneous dispersion of SiC particles in the matrix, high densification, and ultrafine-grain matrix for the samples. The hybrid nanocomposite showed higher wear resistance, lower friction coefficient and enhanced compressive strength in comparison to the microcomposite. The presence of hybrid particles caused a significant decrease of 61% in the matrix grain size, 53% decrease in the width of wear track, and 35% increase in the compressive strength compared to the nanostructured Cu sample. Investigation of the worn surfaces showed that delamination is the predominant wear mechanism in the Cu-SiC composites. Using hybrid SiC led to decreasing the formation of cracks and pits, and plastic deformation in the worn surfaces.