Microstructure‐Dependent Bonding of Wear Debris in 13Cr–4Ni Martensitic Stainless Steel: A Molecular Dynamics Study

The atomic‐scale consolidation of wear debris into a debris‐derived tribological layer is critical to the sliding response of martensitic stainless steel, yet the role of initial microstructure in debris bonding remains elusive. This study elucidates these mechanisms by coupling theoretical microstructural parameter calculations with molecular dynamics simulations across distinct quenched, tempered, and dual‐phase configurations. The results reveal that friction‐induced amorphization dominates the structural transformation. Lower martensitic dislocation density and lattice constant promote crystalline phase transformation but slightly suppress amorphization, whereas reversed austenite enhances amorphization and inhibits martensitic transition. The simulations reveal a progressive bonding pathway involving mechanical interlocking, short‐range atomic interaction, and atomic‐diffusion‐assisted interfacial bonding. The amorphous state enhances atomic mobility, with diffusivity following Ni > Cr > Fe > Si. The results further distinguish intrinsic atomistic bonding propensity from the macroscopic compactness of the worn surface layer, which is additionally controlled by deformation compatibility, oxide‐film rupture, debris generation, and local contact conditions. The superior deformability of the dual‐phase structure accelerates oxide‐film rupture and nascent surface contact, thereby promoting gap healing and layer densification. These findings provide theoretical guidance for designing high‐performance debris‐derived tribological layers more effectively through coordinated optimization of initial microstructural deformability and atomic‐scale bonding activity.