Wear Resistance of Hard Particle Reinforced Copper Alloys Generated by Laser Melt Injection

Abstract

Highly conductive copper alloys are used for several tools in casting and welding technology. In order to improve the poor wear resistance of these alloys, metal matrix composite (MMC) layers were generated by laser melt injection (LMI). During LMI, a weld pool is induced on a substrate by a laser beam and a wear-resistant filler material is injected into this weld pool by a powder nozzle. In contrast to laser cladding, the filler material remains in the solid state and the substrate works as matrix material. Thereby, specific material properties of the substrate - e.g. a high thermal conductivity - can be provided not only in the core of the part but also within the coating. Fused tungsten carbide (FTC) was used as reinforcing material. It was shown that homogeneous MMC layers out of the copper alloy Hovadur® CNCS and FTC can be produced by laser melt injection. High process velocities of 8.75 m/min could be reached. For assessing the wear resistance, oscillating wear tests with counterparts made of steel were carried out and the wear height and the wear volume were determined. The particle reinforcement lead to a significant increase in wear resistance. Only one wear mechanism - abrasion - was identified.