Boosting Wear Performance and Corrosion Resistance by Grain Boundary Framework Reinforcement of NiCu Alloys

Abstract

A method to strengthen nickel-copper alloys involves introducing nanoparticulate phases to encourage a chain-like structure at grain boundaries. Wear resistance improves through grain refinement, dislocation hindrance, and hard reinforcing phases, while corrosion resistance benefits from blocked corrosion pathways. Nickel-copper (NiCu) and 3, 6, and 9 wt% nanotungsten carbide/nickel copper (WC/NiCu) deposition specimens are prepared by the directed energy deposition technique. Lattice dispersion strengthening, solid solution strengthening, and fine grain strengthening synergistically increase the microhardness of NiCu alloys, and the microhardness of 6 wt% nano-WC/NiCu is increased by 16.3% compared to NiCu-deposited specimens. The coefficient of friction is reduced by 11.1% and the amount of wear is reduced by 84.87% in the ring-block friction and wear experiments at a loading of 150 N. This increase in wear resistance is attributed to the increase in overall hardness and the formation of a hard protective layer of tungsten carbide (WC) within the composite-deposited specimen. The composite's corrosion resistance improves with 29.9% lower corrosion current and 111.2% higher polarization resistance, as precipitated carbides and dense grain boundaries block corrosion channels.