Grinding Characteristics and Surface Roughness Modeling of 2.5D Woven SiCf/SiC Ceramic Matrix Composites

SiCf/SiC ceramic matrix composites are considered highly promising for use in engine thermal structures due to their outstanding properties, including high temperature and corrosion resistance. Nevertheless, the challenging machinability of the material leads to difficulties in material removal, decreased grinding efficiency, and inferior grinding surface quality, prompting the need for further investigation. In this study, a prediction model is developed for the surface roughness of machined composites by integrating the properties of the composites and the maximum undeformed thickness. Furthermore, grinding experiments were performed on 2.5D woven SiCf/SiC composites to validate the model's reliability and thoroughly investigate grinding characteristics, such as grinding force, temperature, surface roughness, damage morphology, and material removal mechanism. The results demonstrate a low average error rate of 3.7% for the model, indicating its good reliability. Moreover, the machined surface quality is significantly affected by the grinding depth, which is attributed to the variations in maximum undeformed chip thickness and contact arc length. Increasing the feed speed and grinding depth results in higher grinding force and surface roughness. Conversely, the spindle speed has the opposite effect but leads to elevated grinding temperature. The primary removal mechanisms for this material include matrix cracking, fiber fracture, fiber abrasion or stripping, and interfacial debonding. This study presents valuable theoretical guidance for enhancing and controlling the processing quality of ceramic matrix composites.