Material removal mechanism of SiO2f/SiO2 composites in tangential ultrasonic-assisted scratching

Quartz fiber-reinforced silica ceramic matrix (SiO 2f /SiO 2 ) composites are advanced ceramic matrix composites (CMCs) that exhibit excellent high-temperature resistance, wave transmission, and mechanical properties, making them widely used in the aerospace field. Ultrasonic-assisted grinding (UAG) has proven to be an effective method for machining CMCs. However, due to differences in material composition and structure, the mechanism of UAG of SiO 2f /SiO 2 composites is unclear and requires further investigation. In this study, a single-particle diamond scratching test was carried out to investigate the material removal behavior and surface formation mechanism of SiO 2f /SiO 2 composites by comparing conventional scratching (CS) and tangential ultrasonic-assisted scratching (TAUS). The scratch trajectory characteristics of TAUS were analyzed. The scratch forces at different scratch depths and ultrasonic vibration amplitudes were measured and compared. Additionally, the profile characteristics of the scratch grooves, such as width and depth in different fiber orientations and the matrix, were analyzed. The surface micromorphology along normal fibers, longitudinal fibers, transverse fibers, and matrix of SiO 2f /SiO 2 composites was analyzed separately. Both ultrasonic vibration and fiber orientations significantly influence the removal behavior of SiO 2f /SiO 2 composites. Tangential ultrasonic vibration was proven to effectively reduce scratch force, improve material removal efficiency, and reduce machining damage. This study provides a reference for analyzing the mechanism of tangential ultrasonic-assisted scratching of SiO 2f /SiO 2 materials.