Nanosecond UV laser-induced subsurface damage mechanism and mechanical responses for cemented tungsten carbide

Subsurface damage induced by laser processing critically influences the mechanical properties and service life of cemented tungsten carbide. To elucidate the mechanisms governing laser-material interactions, this study systematically investigates surface and subsurface damage in WC/12Co through nanosecond UV laser ablation, employing angle polishing, Vickers indentation, and multi-scale characterization techniques. The results demonstrate that the ablative morphology, characterized by re-solidified and deposition area, provides insights into subsurface damage mechanisms comprising micro-pores, broken, cracks and the heat-affected zone (HAZ). Effective laser pulse energy is a key parameter in determining ablation efficiency. In the HAZ, reductions in hardness and fracture toughness exhibit a gradient distribution, localized within the laser pulse energy diffusion range. These findings provide valuable insights for optimizing laser processing parameters to mitigate subsurface damage in cemented tungsten carbide.