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Investigation of microstructure, mechanical, and tribological properties of solid self-lubricating copper hybrid composites processed by solid-state mixing technique

In this experimental study, Cu-5 wt% Gr-X wt% SiC (X = 0, 5, 10, and 15) metal matrix hybrid composites were successfully fabricated using solid-state mixing (powder metallurgy) technique through the conventional atmospheric sintering process. The effect of hard reinforcement SiC content on the microstructure, density, micro-hardness, wear resistance, and coefficient of friction of copper-based hybrid composites were investigated. The effect of the percentages of hard reinforcement, applied normal load (L), sliding distance (D), and sliding speed (V) on wear resistance and anti-friction properties of composites were estimated at room temperature under dry sliding conditions using a pin-on-disc apparatus. The tribological test with an investigational plan of six applied loads (10–60 N), six sliding distances (500–3000 m), and five sliding speeds (0.5–2.5 m/s) were performed to record the loss in mass due to dry sliding wear. The result illustrated that the wear loss of the composite containing 15 wt% of SiC were superior to that of the other composites and unreinforced copper. The sintered cylindrical pins have been characterized by X-ray diffraction. Optical microstructural studies showed that the distribution of the hard SiC and soft graphite reinforcements were uniform on the copper matrix. The worn surfaces and wear debris of worn surfaces were analyzed through a scanning electron microscope to identify the type of wear mechanism involved in copper-based hybrid composites.