International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

Two-layer diamond-hard alloy plate is the cutting element of the drill bit and consists of a layer of polycrystalline diamond compact (PDC) binded with the superhard alloy substrate (WC-Co).
In PDC cutter developed in FSBI TISNCM the plate of PDC, 2-3 mm thick and up to 18 mm in diameter, is bonded with a substrate of
WC-Co, forming the working element of the drill bit. PDC consists of a diamond frame with grains of 20-10 microns impregnated with a binder metal Co. The ratio of the diamond fraction and the binder metal, as well as the size of the diamond grains vary, depending on the specifications. The entire PDC cutter is manufactured using high pressure and high temperature technology. The surface of the PDC plate is ground and polished to the required values.
Full-scale tests of PDC cutters showed that their impact strength and wear resistance are determined by the quality of the contactlayer between the PDC and the substrate.
The paper presents the results of the study of the mechanical characteristics of PDC cutters, as well as the microstructure, element and phase composition and defects of the contact layer of PDC with substrate.

Nanostructured boron carbide/C₆₀ (B₄C/C₆₀) and cubic boron nitride/C₆₀ (c-BN/C₆₀) carbon-ceramic composites were prepared by a high-energy ball milled pre-treatment of the parent materials with the addition of a CS₂ solvent followed by a high-pressure/high-temperature (HPHT) treatment. Tthe elastic moduli were calculated based on the experimentally measured density and velocity values of the longitudinal and transverse bulk acoustic waves (BAW) in the specimens. The BAW velocities were measured with a pulse-echo method by laser optoacoustic excitation of ultrasonic pulses. Acoustic microscopy was used to visualize the bulk microstructure and internal defects and to measure the local values of BAW velocities of specimens on which the elastic moduli had been calculated and compared with the data defined by the pulse-echo method. The microhardness and flexural strength of the samples were measured also.