Material removal mechanisms during ultrasonic vibration-assisted grinding of WC-10Co-4Cr coatings with a single diamond grain

WC-10Co-4Cr coatings are widely used in aerospace wear-resistant components due to their exceptional hardness, wear resistance, and corrosion resistance. WC-10Co-4Cr coatings produced by high-velocity oxygen fuel (HVOF) exhibit significant surface roughness of 4–6 µm, require grinding to meet service requirements. However, their extreme hardness poses challenges in conventional grinding, resulting in excessive grinding forces and poor surface quality. Ultrasonic vibration-assisted grinding (UVAG) has been demonstrated to improve the grinding performance of brittle materials by adding high-frequency vibration to the workpiece. In this paper, the material removal mechanisms of WC-10Co-4Cr coatings are discussed through single-grain diamond comparative experiments, including grinding forces, calculation of brittle removal proportion on groove surfaces, and measurement of subsurface crack depth beneath grooves. Results show that under high-speed conditions, ultrasonic can alter the coefficient of friction in wheel-workpiece contact zone and reduce grinding forces by 4.28%-61%. Ultrasonic vibration suppresses the generation of macro-fractures and generates more multi-level micro-cracks on the machined surface, produces smoother groove tracks, and decrease the brittle removal proportion in WC-10Co-4Cr coatings by 26.7%. UVAG alters the crack propagation pattern from predominantly radial to primarily lateral and reducing grinding-induced damage depth from 37 µm to 31 µm, and finally lead to enhanced surface quality.