In Situ Synthesized (Cr, Fe) 7 C 3 -Reinforced Composite Coatings via Laser Cladding Deposition of Fe-Based Alloys and Carbon Fibers

A (Cr, Fe)7C3 carbide-reinforced composite coating is fabricated via laser-irradiating cladding deposition of a Fe60 alloy powder and carbon fibers (CFs) mixture onto a 16Mn steel substrate surface. The microstructure, microhardness and wear resistance of the composite coating are investigated. High-hardness (Cr, Fe)7C3 carbides are uniformly embedded in the ductile γ-Fe/(Cr, Fe)23C6 lamellar eutectics matrix, with some B4C nanoparticles and unmelted CFs also present in the matrix. The composite coating possesses much higher microhardness, anti-friction and wear resistance properties than the steel substrate due to the combined action of the (Cr, Fe)7C3 carbides and γ-Fe/(Cr, Fe)23C6 lamellar eutectics. Micro-cutting and severe plastic deformation are the main wear mechanisms of the substrate, whereas micro-scratching is the predominant wear mechanism of the composite coating, with the formation of a lubricating film mitigating wear on the coating surface.