Study on surface defect formation mechanism in ultrasonic vibration-assisted grinding of SiCp/Al composites

Ultrasonic vibration-assisted grinding (UVAG) is an effective method for high-quality and efficient processing of advanced composite materials. However, the material removal and defect formation mechanism of SiC particle-reinforced aluminum matrix (SiCp/Al) composites in UVAG processing are still unclear. This limits the application of UVAG in composite processing. In this work, a microstructure-based finite element model, in which the properties of SiC particle, Al matrix, and the interfacial layer between SiC particle and Al matrix are considered, has been developed in order to more accurately describe the deformation and failure behavior of SiCp/Al composites in the ultrasonic vibration-assisted grinding process. The influences of complex interactions between tool, particle, and matrix under different tool-workpiece contact modes on material removal and surface defect formation mechanism are analyzed based on the proposed model. Simulation results show that groove and pit defects are more likely to occur in the tool-workpiece continuous contact mode while voids and particle fractures often appear in the tool-workpiece intermittent contact mode. The validity of the proposed model is verified by the corresponding ultrasonic vibration-assisted scratching experiments in terms of surface morphology, defect characteristics, and scratching force. Experimental results are found to correspond well with the outcome of the simulation. The findings reported in this work provide a theoretical basis for exploring effective methods to reduce machining defects and improve the quality of machined surfaces.