Effect of cast tungsten carbide powders on microstructure and mechanical properties of polycrystalline diamond compact bit matrix

Polycrystalline diamond compact (PDC) bit matrix materials were fabricated by pressureless infiltration method using the cast tungsten carbide powders mixed with nickel powders as the skeleton powders. The effects of the morphologies, particle sizes and content of the cast tungsten carbide powders on the microstructure and mechanical properties of the PDC bit matrix were investigated in detail. The results show that the microstructure and mechanical properties of the prepared PDC bit matrix are significantly affected by the morphologies, particle sizes and content of the cast tungsten carbide powders. In contrast to the traditional cast tungsten carbide, the bit matrix, prepared by using spherical cast tungsten carbide powders with moderate particle size as the skeleton, shows a more homogenous and denser structure and obtained enhanced mechanical properties. The PDC bit matrix, prepared by using spherical cast tungsten carbide powder with particle size of 150-180 μm mixed with 13wt% nickel powders as the skeleton, exhibits better mechanical properties than that of the petroleum industry standard SY/T 5217-2000. Its hardness, impact toughness and bending strength were HRC 34 and 6.7 J/cm² and 820 MPa, respectively.