Abstract: SiC particle reinforced aluminum matrix (SiCp/Al) composites are important lightweight metal matrix composites widely used in aerospace and precision instrument fields. However, the existence of SiC hard particles can easily lead to the severe wear of the bit in the process of drilling, and then deteriorate the surface quality of machining. In this paper, the machining characteristics of traditional and ultrasonic vibration assisted drilling of SiCp/Al composites under dry and wet cutting conditions, including burr damage at hole outlet, surface roughness of hole wall and tool wear, are studied, and a set of low damage drilling technology is established. The experimental results show that ultrasonic vibration assisted drilling can effectively reduce the drilling force in the cutting process. Compared with traditional drilling, the average cutting force is reduced by 8.32%. The outlet burr height can be reduced simply and effectively by installing the bottom plate of the workpiece. Both the introduction of cutting fluid and ultrasonic vibration assisted machining can improve the accuracy of hole machining. Compared with traditional dry cutting, the hole wall roughness under ultrasonic vibration assisted drilling is reduced by 27.3%, and the hole wall surface roughness can be reduced by 12.3% with the introduction of cutting fluid. For the drilling of the SiCp/Al composites, the tool wear mechanism can be divided into two-body particle wear, three-body rolling wear and adhesive wear. Ultrasonic vibration assisted machining can effectively reduce the tool wear and improve the tool life. The research in this paper can provide theoretical guidance for low damage hole making of SiCp/Al composites.

Key words: SiCp/Al composites, ultrasonic vibration assisted drilling, surface roughness, tool wear