Effects of mechanical milling time on densification, microstructural characteristics and hardness of Cu-SiC nanocomposites prepared by conventional sintering process

In this study, effects of the milling time on densification, microstructural characteristics and mechanical properties of Cu-SiC nanocomposite produced by high energy mechanical milling and conventional sintering process are investigated. Cu-SiC powder was milled for different durations and then cold compacted under 800 MPa pressure followed by conventional sintering at 900 degrees C under argon atmosphere for 1 h. The microstructural characterization was conducted by x-ray diffraction (XRD), scanning electron microscope (SEM), and scanning transmission electron microscope (STEM). The highest densification for the composite powder was obtained at a short milling time, where the powder showed flake morphology and lower strain-hardening. By increasing the milling time, the size of the Cu matrix grains refined and the level of microstrain and microhardness of the nanocomposite improved. The incorporation of the nanoparticles in the Cu matrix increased the microhardness of the copper. This effect was more evident in lower milling durations.