Mechanical and wear properties of hybrid aluminum matrix composite reinforced with graphite and nano MgO particles prepared by powder metallurgy technique

In the present study, aluminum–5 wt% graphite self-lubricating composites with 0, 1.5, 2.5, 3.5, and 4.5 wt% of MgO nanoparticles were prepared by utilizing powder metallurgy route to achieve high mechanical and wear properties. The hybrid composites were characterized by using a scanning electron microscope (SEM) and X-ray Diffractometer (XRD). The dry sliding wear test was performed under various loads of 5, 10, 15 and 20 N at a constant sliding distance of 1810 m. It was found that increasing nano–MgO content results in a decrease in density and an increase in porosity. By increasing the weight fraction of MgO nanoparticles improved both the micro-hardness and diametral compressive strength, until an optimum value up to 2.5 wt% and then, the severe reduction was observed. The wear rate reduced with improving the amount of nano–MgO particles up to 2.5 wt% then increased for all applied loads and also the wear rate is still lower when the MgO content is 1.5 and 3.5 wt% compared with that without MgO nanoparticles. Additionally, the wear rate for all hybrid composites positively correlated with the applied loads. Lastly, the results revealed that the hybrid composites with 2.5 wt% MgO nanoparticles showed better mechanical and wear properties.