Effect of Cu/Ni coating on the interface and mechanical properties of Cf/2024Al composites

Abstract

To improve the interface between the carbon fiber and aluminum matrix, the carbon fibers were modified with Cu coating and Ni coating by using electroless plating. The Cu-coated and Ni-coated carbon fibers reinforced 2024Al matrix composites (denoted as Cf(Cu)/2024Al and Cf(Ni)/2024Al) were prepared by spark plasm sintering at 480 °C for 10 min under a uniaxial pressure of 30 MPa. Microstructure observations show that the interfacial reaction between carbon fibers and aluminum matrix can be efficiently obstructed by coating the carbon fiber with Ni, while it still proceeds as the carbon fibers were coated with Cu. The nanohardness of the interface for Cf(Cu)/2024Al composite is 2.68 GPa, which is 16.5% higher compared to Cf(Ni)/2024Al composite (2.30 GPa) due to the produced hard Al4C3 at the interface. The tensile strength and strain of Cf(Ni)/2024Al composites are 284 MPa and 6.4%, which are increased by 4.4% and 28.0% respectively compared to Cf(Cu)/2024Al composites. The Ni coating plated on the carbon fiber results in moderate interfacial bonding and avoids damage to the carbon fiber, which is efficient in deflecting cracks and increasing the crack propagation path, as well as consuming more fracture energy.