Coaxial Laser Cladding of Novel Wear-Resistant Alloy Coatings on 60CrMnMo Steel Surface.

Fe-Cr-Nb-Al-C alloy coatings were firstly fabricated on a high-carbon forged steel surface via coaxial laser cladding. The morphological evolution with varying Nb contents and wear mechanisms of the coatings were systematically investigated through comprehensive analysis. The results indicate that Nb content critically governs the coating microstructure and mechanical properties. At low Nb levels, coarse grain-boundary networks of (Fe,Cr) solid solution embrittled by Cr23C6 are formed. Moderate Nb addition produces finely dispersed rod-shaped NbC precipitates. At higher Nb levels, the morphology evolves into a segregated martensite-ferrite dual-phase structure. The coating wear rate exhibits a parabolic dependence on Nb content, initially decreasing with moderate addition and then increasing with further Nb. Consequently, optimal wear resistance is achieved at a critical Nb content (3 wt.%) that establishes an optimal balance between NbC precipitation and phase uniformity, thereby minimizing debris generation and spalling.