Unveiling wear property and multiscale tribological mechanism of laser cladding-nitriding synergistically enhanced high-entropy alloy coatings

Y Zhang and WF Yang and J Peng and AD Wang and WJ Fan and J Li, APPLIED SURFACE SCIENCE, 710, 163878 (2025).

DOI: 10.1016/j.apsusc.2025.163878

High entropy alloys (HEAs) have emerged as a revolutionary class of structural materials owing to their exceptional mechanical properties, compositional adaptability, and multi-element synergistic effects under extreme conditions. Here, laser cladding-nitriding composite treatment significantly enhances the wear resistance of HEA coating produced on the steel, yet the nanoscale deformation mechanisms and interfacial interactions governing its tribological behavior remain poorly understood. Here, we systematically investigate the wear behavior, friction evolution, and microstructure-property relationships of AlN- nitrided/FeCoCrNiAl0.5 HEA coated steel using atomic simulation and experimental analysis. The AlN nitride layer initially exhibits elastic deformation at low indentation depth, transitioning to microplasticity with characteristic force fluctuations arising from atomic rearrangement and localized amorphization. During the sliding, the friction force demonstrates hardening behavior beyond the sliding displacement of 6 nm, attributed to accumulated atomic pile-up and stress-induced AlN phase transformation. Stress distribution analysis reveals that the HEA coating effectively dissipates the shear strain through lattice distortion and dislocation interactions, while suppressing stress propagation to the steel substrate. The AlN-HEA interface forms gradient stress buffers via chemical bonding and modulus-matching design, reducing interfacial delamination risks compared to direct nitride/steel systems. Notably, the dislocation dynamics at heterointerfaces show stress-driven nucleation and constrained slip within HEA lattices, enhancing strain energy absorption. The synergistic combination of surface hardening in AlN nitrided layer, plasticity accommodation in HEA, and interfacial strain-gradient design collectively improves wear resistance, achieving a reduction in friction coefficient fluctuation amplitude relative to single-layer coatings. These findings elucidate the atomic-scale interplay between phase evolution, stress dissipation, and interface engineering in laser-clad composite systems, providing critical insights for designing wear-resistant multilayer coatings.

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