Revealing damage evolution and ablation behavior of SiC/SiC ceramic matrix composites by picosecond laser high-efficiency ablation

The picosecond laser was utilized to fabricate the slanting microholes efficiently on SiC/SiC ceramic matrix composites. The machining damage, material oxidation, and temperature field were mainly analyzed through static and in-situ detections. The damage evolution and ablation behavior of SiC/SiC composites were qualitatively and quantitatively revealed. The results showed that the lowest peak temperature of the slanting microhole was 282.6 °C. The heat accumulation effect and thermal stress that was tensile stress in nature present caused recasts, microcracks, fiber fracture, fiber debonding, and fiber stripping. Fibers and matrix underwent slight oxidation, forming SiO₂ recasts through the phase transition. The pulse energy, frequency, and inclination angle regularly affected the quantity, size, and distribution of microcracks, material removal rate (MRR), and hole wall roughness. The maximum MRR was about 2.5 mm³/s, corresponding to the minimum time was 0.9 s. The circularly polarized picosecond laser could process parallel striped laser-induced periodic surface structures (LIPSS) on the hole wall.