Ceramic matrix composites have complex structures. For exploring the impact factors of machined surface quality and material removal mechanism, its internal structure must be decoupled, and then a unidirectional C/SiC composite was designed and fabricated in this paper. Through a series of representative surface grinding experiments, the machined surface of the composites was characterized by 3D profile test, and the microscopic characteristics and material removal mechanism of the grinding surface were discussed in detail. The results showed that the fiber orientation had a significant effect on the surface quality, and the order of 3D surface roughness was longitudinal > normal > transverse. On the basis of the systematic analysis of the microscopic characteristics of the machined surface, the brittle fracture was the dominant form of material removal in grinding process. Further, combined with 3D surface profile and surface micromorphology, the effect of fiber orientation on the removal mechanism of composites was revealed. The results not only enrich the machinability and improve the surface quality of unidirectional C/SiC composites, but also provide some guidance for grinding of the woven composites.

No abstract