Material removal and damage formation mechanisms during ultrasonic vibration-assisted grinding of high volume fraction SiCp/Al composites

High volume fraction silicon carbide particle-reinforced aluminum matrix (SiC_p/Al) composites are applied in aerospace industries owing to their superior properties. However, the hardness, brittleness, and uneven distribution of SiC particles often lead to fluctuations in grinding force and surface damage during conventional grinding (CG). At high volume fraction, the overall brittleness of SiC particles increases, resulting in a higher grinding force and exacerbated machining defects. Ultrasonic vibration-assisted grinding (UVAG) has shown significant advantages in machining brittle and hard materials. In this study, comparative experiments were performed on SiCp/Al composites with 60 vol% SiC particles using a single abrasive grain under CG and UVAG conditions, aiming to reveal the material removal and damage formation mechanisms. The results indicate that UVAG reduced the normal grinding force F_n by 19.8 %–29.3 % and the tangential grinding force F_t by 21.3 %–30.1 %, while also decreasing the specific grinding energy by 26.7 %–35.4 % compared to CG. Additionally, the scratching quality was also improved, with the surface roughness S_a reduced by 16.0 %–23.2 % and the average pile-up ratio lowered by 17.1 %–20.8 %. UVAG also effectively suppressed radial crack propagation due to the dense interactions between SiC particles, which inhibited slip and reduced severe subsurface damage. This study promotes the practical application of UVAG in high volume fraction SiC_p/Al composites.