Edge chipping characteristics in grinding SiCf/SiC composite

Abstract

Silicon carbide fiber-reinforced silicon carbide ceramic matrix composite (SiCf/SiC) is promising for manufacturing aero-engines because of its high-temperature resistance and lightweight. However, since SiCf/SiC is hard and brittle, the machining of SiCf/SiC has been suffering from uncontrolled machining-induced damages, such as edge chipping, cracks, fiber breakage. This paper studies the edge chipping characteristics of SiCf/SiC in brittle removal mode in single grain grinding. It is found that the edge chipping in grinding SiCf/SiC is complicated. The edge chipping in grinding the SiC matrix is dependent on the pre-existed defects rather than grinding parameters. While the edge chipping in grinding SiC fibers is dependent on both fiber orientation and grinding speed. The edge chipping in the grinding perpendicular to the fiber orientation is larger than that in the grinding along with the fiber orientation. It decreases with increasing grinding speed. Increasing grinding speed from 20 m/s to 50 m/s and 90 m/s, the width of the edge chipping area decreases by 30% and 60% respectively. While in the grinding along with the fiber orientation, edge chipping is minor and insensitive to grinding speed. Therefore, this study represents that increasing grinding speed would not enlarge the edge chipping but greatly increase the material removal rate, which is important for the surface finish and damage control of the machining of SiCf/SiC.