Experimental investigation on tool wear in ultrasonic vibration-assisted turning of SiC_f/SiC ceramic matrix composite

Silicon carbide fiber-reinforced silicon carbide matrix composites have attracted attention due to superior properties, such as low density, high strength, and high-temperature resistance. However, it often faces severe tool wear during cutting, with the fibers and matrix material being of high hardness and brittleness, which has an inevitable effect on the engineering application of this kind of material. In this paper, wear volume V_W is used to evaluate the tool wear through solid modeling and parameter measurement based on the tool wear topography in turning of SiC_f/SiC ceramic matrix composites. Conventional turning (CT), ultrasonic vibration-assisted turning (UVAT), and ultrasonic vibration-assisted turning with water cooling (W-UVAT) experiments are carried out using CBN, PCD, and PDC tools to investigate and analyze the cutting performance. In the meantime, the tool wear mechanism and form are studied based on the analysis of ultrasonic vibration on tool wear, the geometric position of wear, accumulation of cutting workpiece powders, and tool wear curve. Experimental results found that the PDC tool obtains the best cutting performance, which is more suitable for turning silicon carbide fiber-reinforced silicon carbide matrix composites. Within the experimental parameters, with the increased ultrasonic amplitude A, V_W decreases first and then increases, reaching a minimum at A which is 3 µm. The main wear mechanism of the PDC tool is abrasive wear, and the primary wear form is the spalling of polycrystalline diamond abrasive grains.