Microstructure, Mechanical and Wear Properties of Short Carbon Fiber-Reinforced AM50 Magnesium Matrix Composite

The Ni-coated carbon fiber-reinforced AM50 magnesium matrix composites were fabricated utilizing a mechanical coupling electromagnetic stirring technique. The effects of carbon fiber addition amount on the hardness, compressive mechanical properties and wear resistance of Ni-Cf/AM50 composite materials were studied using hardness, compression and friction-wear experiments. The microstructures, interface bonding between the matrix and carbon fiber as well as the characterization of fracture surfaces and wear surfaces of the composite materials were analyzed using scanning electron microscopy and transmission electron microscopy. The results demonstrate that the Ni-coated carbon fibers are uniformly distributed throughout the matrix, and the presence of Ni coating improves the interfacial bonding between the carbon fibers and the matrix. The hardness, compressive strength and wear resistance of the composite material were improved compared to the AM50 alloy. When the addition amount of carbon fiber is 1.0 wt%, the composite material shows a hardness of 79.3 HV, compressive strength of 276 MPa, an average friction coefficient of 0.243 and a wear rate of 0.11%. These values indicate significant improvements of 69.8%, 17%, 13.21% and 85.53% over the AM50 alloy, respectively. The reason for the properties improvement of composite material can be attributed to the combined effect of the uniform distribution of carbon fibers, the good bonding between Ni-coated carbon fiber and the matrix interface and the excellent lubricating properties of carbon fibers.