Stress analysis in scratching of anisotropic single-crystal silicon carbide

Abstract

An expression for the stress distribution around an indenter in scratching of anisotropic single-crystal silicon carbide is derived by the superposition of the elastic stress field and residual stress field. It is an extension of isotropic materials. The elastic stress field can be obtained from the solutions of a point force problem in semi-infinite anisotropic materials using Green's function method. The calculation of residual field due to plastic deformation adopts a center of dilatation model. The plastic deformation zone beneath the indenter is simplified to a hemisphere based on the crystal-plasticity theory for single-crystal silicon carbide. The dilatation of the hemi-spherical plastic zone attached on the free surface of a semi-infinite solid is solved by a doublet force system. The values of stresses obtained from this calculation method match well with those calculated using classical solutions when the problem degenerates into isotropic materials. In addition, the stress field when scratching on the (0001) plane of 4H-SiC with a conical diamond indenter is presented using the new calculation method. In previous studies, the 4H-SiC was usually simplified as isotropic materials. However, it is found that the values of tensile stresses along the c-axis leading to median cracks are 1.4 times higher than those in isotropic materials. Therefore, it is not appropriate to simplify the single-crystal silicon carbide as an isotropic material when analyzing the scratching-induced stress field.