Effect of Heat Treatment on Tribological Properties of SiCp/Al–Mg–Mn–Cu Aluminum Matrix Composites

The tribological behaviors of SiCp/Al–Mg–Mn–Cu aluminum matrix composites under solid solution (labeled as SS sample) and aging treatment (labeled as SA sample) were systematically investigated. The microstructures, tribological properties and wear mechanisms of worn surfaces were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM) and wear testing machine, respectively. The microscopy study showed the uniform distribution of reinforcements in the SiCp/Al–Mg–Mn–Cu composites. And a large number of fine CuMgAl₂ phases were observed in the untreated sample but dissolved in the SS sample to some extent. It can be confirmed that the size and number of some new precipitates and CuMgAl₂ phases were in the suitable state for the SA sample resulting from its excellent integrated mechanical properties. A good combination of strength and plasticity in SA sample was corresponding well with its much lower coefficient of friction (COF) and well abrasion resistance, with a COF of 0.25. The wear mechanisms of the untreated and SS samples have found to be the combination of abrasive and adhesive indicated by the presence of some wear debris and delaminated flakes, whereas the wear mechanism is changed to adhesive dominantly with slight delamination in case of SA sample.