Material removal mechanism of SiC_f/SiC composites during ultrasonic-assisted scratching with vertical vibration

Ultrasonic-Assisted Grinding (UAG) is a novel manufacturing technology that shows promising promise for use in processing Ceramic Matrix Composites (CMCs). Nevertheless, analyzing the material removal process of CMCs with multidirectional structure during UAG is challenging, impeding the progress and improvement of the UAG process. This work examined the impact of ultrasonic vibration on the dynamic mechanical characteristics during processing. Additionally, we experimentally elucidated the material removal mechanism of CMCs during the scratching process under the influence of vertical vibration. The results indicate that the introduction of ultrasonic vibration causes a strain rate effect, resulting in a modification of the material removal mechanism, subsequently impacting the processing quality. Ultrasonic vibration increases the dynamic strength and brittleness of the fibers in CMCs, leading to more cracks at fracture, which changes from the original bending fracture to shear fracture. In addition, ultrasonic vibration can effectively inhibit the impact of scratching depth and anisotropy on the removal mechanism of CMCs, resulting in a more uniform surface of CMCs after processing.