Investigation on the material removal and damage suppression mechanisms of SiCp/Al composites by in-situ laser-assisted diamond cutting

In-situ laser-assisted diamond cutting presents a promising approach for ultra-precision machining of SiCp/Al composites. However, the material removal and damage suppression mechanisms under coupled thermo-mechanical effects remain insufficiently understood. In this study, a finite element model incorporating temperature-dependent material properties was developed to investigate the role of laser assistance in enhancing machining performance. The effects of laser power, depth of cut, and cutting speed on the material removal behaviour were systematically analysed, and corresponding experiments were conducted to validate the simulation results. The results demonstrate that laser assistance significantly improves the plastic deformability of the matrix. The cutting force and machining stress were reduced by up to 31% and 59.9%, respectively, while large defects associated with particle fracture and pull-out were effectively suppressed. An optimal surface roughness of 11.2 nm was achieved, compared with 78.9 nm obtained under conventional diamond cutting. In addition, subsurface defects, including amorphization, dislocations, and stacking faults, were markedly inhibited owing to the laser annealing effect. Appropriate laser power enhances material machinability, whereas excessive laser power reduces interfacial bonding strength and induces excessive matrix deformation. The depth of cut determines the interaction position between the cutting edge and the particles, with smaller depths of cutting favouring improved surface integrity. Cutting speed exerts opposing effects on surface integrity. Lower cutting speeds allow greater laser energy accumulation, which facilitates material softening. However, they also prolong material deformation time, leading to increased surface roughness. This study provides important theoretical guidance for the ultra-precision machining of SiCp/Al composites.