Microstructure and properties of graphite-reinforced copper matrix composites

In this study, copper matrix composites reinforced with graphite (5, 10, 15 wt%) were produced using powder metallurgy process. Milled powders were compacted under 637 MPa pressure to produce cylindrical specimens of approximate dimension of 10 mm diameter and 30 mm length. Cylindrical specimens were sintered under vacuum at 900, 950, 1000 degrees C for 2 h holding time at highest temperature. Hardness and compression strength of composite samples were determined. The microstructures of specimens were investigated by optical microscope, scanning electron microscope and energy-dispersive spectroscopy. Homogeneous distribution of reinforcement phase in copper matrix composites was observed. Graphite reinforcement improved the compression strength of composites of around 108% with 5 wt%, around 34% with 10 wt% of reinforcement. However, significant decrease of compression strength was observed with 15 wt% of graphite reinforcement in the copper matrix. Reinforcement of graphite into copper matrix has improved the wear property of the composite materials.