Some observations in grinding SiC and silicon carbide ceramic matrix composite material

The ceramic has extensive applications in aeronautics and transportation industry because of outstanding properties, but the processing performance is poor. The carbon fiber-reinforced SiC matrix composite (C_f/SiC) is proposed to improve machining performance. The carbon fibers have important effects on surface quality and forces when machining C_f/SiC materials. But there are few investigations about the related contents. To fill these gaps by comparing SiC and C_f/SiC composites is the main objective of this study. The C_f/SiC materials were machined in two different directions. To explore the grinding mechanism, some evaluation parameters were investigated. The extension of cracks is the main removal method during grinding process of SiC. While matrix craze, fiber fracture, and interfacial debonding are the main remove methods of Cf/SiC composites. While grinding 2.5 D C_f/SiC material, fiber pullout, outcrop, fractures, wear, interfacial debonding, and matrix cracks were the major failure forms. During machining, the roughness of the machined surface decreased with reducing grinding speed v_s, whereas the grinding depth a_p and feed speed v_w brought contrary effects. Meanwhile, the grinding forces gradually improved with increasing a_p and v_w, and decreasing v_s. On the basis of conclusions, the surface roughness and grinding forces of the SiC and 2.5 D C_f/SiC materials could be derived. This series of analysis and researches provides useful technical support on understanding the grinding mechanism of SiC and 2.5 D C_f/SiC material.