Investigations on the material removal and damage formation mechanisms of WC-Co cemented carbide in hybrid laser softening and single-grain scratching processes

Abstract

Cemented carbide poses significant challenges in precision and damage-free machining due to its extreme hardness and brittleness. This study investigates the material removal mechanisms in Laser-Assisted Machining (LAM) through quasi-static and grinding-type Single-Grain Scratching (SGS) experiments on WC-Co cemented carbide (K10 grade). The effects of Laser Softening Degree (LSD), scratching modes, loads, and strain rates were systematically analyzed, focusing on friction/wear behavior and crack propagation. And the LSD was quantitatively characterized by the Heat-Affected Zone overlap ratio (O_HAZ). Results demonstrate that laser softening can effectively reduce the surface friction coefficient (by approximately 40 %) and scratching forces while inhibiting tool wear and surface damage. Acoustic emission signal reveals the formation of brittle chips and radial crack networks during scratching. Furthermore, grinding-type SGS shows a distinct transition from the deformation removal stage to the elastic contact stage. Notably, increasing LSD and scratching speed (4.45 m/s ∼ 40.08 m/s) can both significantly inhibit scratching surface wear and enhance the mechanical response rate of the subsurface microstructure. This work provides fundamental insights into thermal-mechanical coupling in LAM, offering practical guidance for controlling grains’ wear in the precision machining of cemented carbides.