Evaluation of microstructure, thermal and mechanical properties of Cu/SiC nanocomposites fabricated by mechanical alloying

Nano-sized silicon carbide (SiC; 0, 1wt%, 2wt%, 4wt%and 8wt%) reinforced copper (Cu) matrix nanocomposites were manufactured, pressed and sintered at 775 and 875°C in argon atmosphere. Both X-ray diffraction (XRD) and scanning electron microscope (SEM) were carried out to characterize microstructural evolution. The density, thermal expansion, mechanical and electrical properties were studied. XRD analyses showed that by increasing SiC contents, the microstrain and dislocation density increased, while crystal size decreased. It was found that the coefficient of thermal expansion (CTE) values of nanocomposites samples were lower than that of Cu matrix. The improvement of CTE with increasing sintering temperature may be due to the densification in their microstructure. Moreover, the mechanical properties of these nanocomposites showed noticeable enhancement by the addition of SiC and sintering temperatures where microhardness and apparent strengthening efficiency of nanocomposites contain 8 wt% SiC and sintered at 875 °C were 958.7 MPa and 1.07 1/vol%, respectively. Electrical conductivity of these samples slightly decreased with the addition of SiC contents and increased with sintering temperature. Based upon the aforementioned results, we can conclude that the prepared Cu-SiC nanocomposites possess good electrical conductivity, high thermal stability and excellent mechanical properties.