Thermal residual stress of polycrystalline diamond compacts

Thermal residual stresses in polycrystalline diamond compact (PDC) cutter arising from the difference in thermal expansion between the polycrystalline diamond (PCD) and the supporting tungsten carbide substrate after sintering at high pressure and high temperature were investigated using finite element simulation, laboratory tests and theoretical analysis. The obtained results show that although compressive residual stresses exist both in the interface of PCD table and in the most region of PCD table surface, the tensile residual stress, which is a fatal shortage to PDC, can also occur near the outer diameter area of PCD table, and the maximum value is 690 MPa. Distribution of tensile stress in the PCD table is given through experimental results, which is well consistent with the numerical results. This finding may be significant in designing new PDC cutters with lower residual stress and high cutting behavior.