Effects of grinding speed on the material removal mechanism in single grain grinding of SiCf/SiC ceramic matrix composite

Abstract

Silicon carbide (SiC) fibers reinforced SiC ceramic matrix composite (SiCf/SiC) is an advanced material for aeroengines because of its high-temperature resistance and high specific strength. However, it is rather difficult to machine. Though there have been many methods available for machining SiCf/SiC, the material removal mechanism is not fully understood and the machining efficiency is still low. This paper studies the effects of grinding speed on the material removal mechanism of SiCf/SiC by single grain grinding. Results indicate that increasing speed grinding could embrittle the material and enhance the breakage of fibers. When grinding along the fiber longitude direction, fibers present brittle fracture and matrix is torn off in high speed grinding rather than the ploughing in fibers or the smearing in matrix in low speed grinding. When grinding transverse to the fiber longitude direction, fibers are removed completely without any residual cut-off fiber end which is common in low speed grinding. Both the groove surface quality and machining efficiency are improved by increasing speed grinding.