Study on grinding surface deformation and subsurface damage mechanism of reaction-bonded SiC ceramics

Abstract

In order to explore the grinding surface deformation and subsurface damage mechanism for reaction-bonded SiC ceramics, the grinding experiment for reaction-bonded SiC ceramics was carried out under the condition of different grinding depths using two different kinds of grain sizes of grinding wheel. The ground surface morphology of specimen was observed using the field emission scanning electron microscope (5000 ×), and the value of surface roughness Rz was measured by the confocal microscope, which found that there were the brittle removal region and the plastic removal region on the ground surface of reaction-bonded SiC ceramics and it could improve the ground surface quality and proportion of ductile region using the fine grinding wheel and reducing the grinding depth. The specimen was polished by the ion cross section polisher and the ground subsurface was analyzed by the field emission scanning electron microscope, which found that there were transgranular fracture, intergranular fracture, crack bifurcation, ladder-shaped crack and other phenomenon in the grinding process. And it could control the subsurface damage depth using the fine grinding wheel and reducing the grinding depth. The relationship between surface roughness and subsurface damage was analyzed based on the indentation theory, which found that the simulation results were close to the experiment results when the value of m is in the range of 1/8–1/4. When m is 0.2143 calculated by genetic algorithm, the simulation results are the best.