Material removal and surface formation mechanism in laser assisted milling of Cf/SiC

Laser-assisted milling (LAM) is proposed as an effective strategy for improving the machinability of carbon fiber-reinforced silicon carbide (C f /SiC) ceramic matrix composites. This study investigates the material removal mechanisms and surface formation behavior during LAM of C f /SiC, with a focus on the interaction between laser-induced thermal effects and the composite microstructure. Experimental results demonstrate that LAM significantly reduces cutting forces—from 1548.8 N in conventional milling to 805.4 N—corresponding to a 48.0 % reduction. This is attributed to laser-induced thermal softening of the SiC matrix and pre-ablation of surface material, which collectively lower the mechanical resistance during chip formation. Moreover, surface integrity is markedly improved. Surface roughness (Ra) decreases from 17.427 μm to 1.464 μm, representing a 91.6 % improvement. SEM and EDS analyses reveal that LAM suppresses fiber pull-out and matrix fragmentation. Although superficial oxidation occurs during laser irradiation, the oxidized layer is subsequently removed by the milling process, resulting in a clean, defect-free surface. These findings elucidate the fundamental mechanisms underlying the enhanced machinability of C f /SiC during LAM and provide a scientific basis for optimizing process parameters in precision machining of brittle composites.