Identifying the causes of residual stress in polycrystalline diamond compact (PDC) cutters by X-Ray diffraction technique

Abstract

An attempt was made to identify the sources of residual stress in polycrystalline diamond compact (PDC) cutters by X-ray diffraction (XRD) technique. PDC retains residual stress after sintering and this residual stress plays an important role for cutter performance. X-ray diffraction method of residual stress measurement is very common because it is nondestructive. Residual stress was measured in a finished 16 mm PDC cutter and changes in residual stress were observed as the substrate was removed by grinding. Residual stress was also measured after full removal of cobalt from the diamond table by leaching. Comparison was made between the as-pressed PDC cutter, after removing the substrate, and after removing the cobalt to understand the relative contribution of geometry and cobalt binder to overall residual stress. An additional measurement was made under High Pressure High Temperature (HPHT) compacted diamond powder in the absence of cobalt to evaluate the contribution of high temperature deformation of diamond particle on residual stress.