Study on the removal mechanism of SiC_f/SiC composites by ultrasonic vibration rotational scratching

SiC_f/SiC composites are important advanced materials in aerospace and energy fields, but their hard and brittle properties lead to severe machining damage during conventional machining, which limits their application performance. In this study, ultrasonic vibration rotary scratching experiments using single crystal diamond particles were conducted to characterize the scratching force and post-machining surface morphology, and to investigate the effect of ultrasonic vibration on the material removal mechanism. The results show that the axial force shows significant fluctuations with the fiber orientation angle, following the pattern of ASF 0° (transverse) ≫ ASF 0° (longitudinal), ASF 30°> ASF 45°. At scratch depths of 30 μm and 40 μm, the average axial force of ultrasonic vibratory scrubbing decreased by 21.61% and 8.80%, and the average tangential force decreased by 25.27% and 15.91%, respectively, compared with the normal planar scrubbing force. In the conventional rotational rubbing, the material surface showed characteristic skewing phenomenon and debonding phenomenon, and the width of the fiber fracture zone after rubbing was large and irregular. All of them were effectively suppressed after the introduction of ultrasonic vibration. This indicates that ultrasonic vibration significantly reduces the processing force and surface damage by changing the material removal mechanism, providing technical support for the precision manufacturing of advanced equipment.