Sawing stress of SiC single crystal with void defect in diamond wire saw slicing

Abstract

At present, the diamond wire saw technology is applied to cut SiC single crystal. As a hard and brittle material, SiC slices may break in cutting due to local stress concentration and mutation. The void-defect, which is a typical defect inside the SiC single crystal can cause local stress concentration and stress field redistribution in wire sawing process. The degree of stress concentration is associated with the size and position of the defects, and understanding the sawing stress change of SiC single crystal with void defect during the wire sawing process is significant for the development of precision slicing technology. In this paper, a finite element model of wire sawing SiC single crystal containing spherical void defect was founded, and the stress concentration and sawing stress field distribution of SiC single crystal containing void defects of different relative positions and sizes have been analyzed. Numerical simulation results show that the stress concentration caused by the defects with different sizes at different relative positions in the cutting process is significantly different, and it does not always increase with the increase of defect size, but is relative to the ratio of defect size to kerf width or slice thickness. When the void defect is located inside the slice and infinitely close to the slice’s inner surface, this is the strongest influence of defect on slice stress concentration and stress field change during the sawing process, which means the possibility of slice breaking is large.