Surface generation mechanism of WC/Co and RB-SiC/Si composites under high spindle speed grinding (HSSG)

The surface generation mechanisms of WC/Co and Reaction-bonded SiC/Si (RB-SiC/Si) composites under high spindle speed grinding (HSSG) were investigated in the present work, compared with quasi-static indentation test. The results showed that surface generation mechanism for WC/Co and RB-SiC/Si varied under both quasi-static indentation and dynamic grinding. Only plastic deformation occurred for WC/Co indicating its higher toughness, while pop-out effect induced by phase transformation in RB-SiC/Si would prompt the chipping at phase boundaries under indentation. Under dynamic grinding, WC/Co underwent plastic deformation, grain dislodgement and WC particles crush, while ductile removal, phase boundaries crack (along the grinding direction) and chipping fracture occurred for RB-SiC/Si with the increase of cutting depth. It was found that the binder in the bulk WC/Co and RB-SiC/Si played a decisive role on the material removal mode, and the mechanics of grain dislodgement for WC/Co and RB-SiC/Si were analyzed based on a geometrical model. Besides, three types of grinding wheel wear appeared, including grit dislodgement, flattening and splintering, which bear an obvious influence on the surface generation.