Friction characterization of SiCp/Al composites by 3D ultrasonic vibration-assisted milling

Silicon carbide particle reinforced aluminum matrix composites (SiCp/Al) have excellent mechanical and physical properties and are widely used in the defense and military industry, aerospace, and so on. However, when machining SiCp/Al, due to the large difference in cutting properties between the particles and the base material, the compression and friction on the tool may cause fluctuations in the cutting force, resulting in poor machined surface quality. Therefore, the study of friction characteristics during machining is necessary and of great significance to improve the machining quality of SiCp/Al. A three-dimensional milling processing method with the help of ultrasonic vibration is proposed in this study. The friction-reducing effect of the processing method is then demonstrated by analyzing the friction characteristics of the tool-workpiece and the friction forms of the aluminum matrix and particles when extruded on each cutter surface. Also, four different volume fractions of SiCp/Al, namely 15, 25, 45 and 60%, were machined by milling to investigate the effect of different ultrasonic amplitudes on the friction coefficient, as well as to study the effect of friction coefficient on the milling force and the machined surface. The results show that the larger the volume fraction, the larger the friction coefficient and milling force. Moreover, an increase in amplitude leads to an increase and then a decrease in the friction coefficient. The friction coefficient is reduced by up to 83% compared to conventional milling, and an increase or decrease in the friction coefficient leads to an increase or decrease in the milling force and the roughness of the machined surface.