Study on multi-scale ablation behavior of C/SiC composites under high-energy CW laser irradiation

This work conducts ablation experiments and multi-scale numerical simulations of C/SiC composite materials under CW laser action. The highest surface temperature, macroscopic and microscopic ablation morphology, and approximate ablation threshold for C/SiC composites at different power densities were obtained. A multi-scale ablation calculation method for C/SiC composite materials under CW laser action was established using the level-set method. At the meso-scale, a macro-mesoscopic cross-scale surface ablation model was established, taking into account factors such as solid heat transfer, heat exchange of chemical reactions, differential temperature rise process between internal fibers and matrix, and differences in ablation behavior of two-dimensional plain weave fabrics. The experimental and microscale simulation results indicate that different ablation behaviors (oxidation and sublimation) occur in different regions, resulting in “shoot tip” fibers and residual matrix pore morphology. This work can provide theoretical and experimental basis for the design and precision machining of C/SiC materials.