Water-assisted laser ablation of silicon carbide: Damage evolution and underlying mechanisms

To address severe thermal damage in silicon carbide laser processing, this study employs molecular dynamics (MD) to investigate atomistic damage evolution following ultrafast energy deposition in SiC under vacuum and water-assisted conditions. The findings demonstrate that the aqueous medium significantly suppresses the heat-affected zone, yielding an approximately 43% reduction in damaged atoms in the present MD model. Through coupled rapid quenching and interfacial confinement, the water layer attenuates stress redistribution, restricts damage near the surface, and helps preserve a locally ordered near-surface layer while a localized subsurface phase-transformation zone remains. Furthermore, Partial radial distribution function analysis indicates that the water-assisted condition better preserves local Si–C coordination and medium-range sublattice correlations within the simulated time window. Within the present MD energy-input window, the simulated crater morphology exhibits a transition from depth-dominated to width-dominated growth between 6000 and 6500 eV/ps, indicating that lateral energy redistribution becomes increasingly dominant under water-assisted conditions. This research elucidates how the aqueous medium regulates energy partition and damage evolution via a synergistic “thermal dissipation-mechanical confinement-stress modulation” mechanism, providing atomistic-level mechanistic guidance for interpreting experimentally observable damage suppression and morphology evolution in water-assisted ultrafast laser processing of SiC.