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The paper is dedicated to the enhancement of Polycrystalline Diamond Bits (PDC) designed for oil and gas industry. A novel diamond-reinforced composite was applied for cutting inserts, with the addition of 4 wt% chromium diboride to the WC-Co matrix. The addition of CrB2 ensured improvement of bending strength and fracture toughness by nearly 30% and 40%, respectively, and enhanced the diamond retention force. The efficiency of PDC bits was further improved by incorporating constructional features in both bottomhole and reaming parts. An analytical relationship between the feeding speed and geometrical parameters was found, including the wings and calibrating inserts numbers, as well as the rotational speed of the cutter. Under the conditions of rock fracture by reaming inserts, the approximate value of the required power was calculated.

The study is devoted to structure and mechanical properties of a diamond composite used for manufacturing of cutting tools applied in a wide range of technological fields. The sample tools were fabricated by cold-pressing technology followed by hot-pressing in vacuum of the 51Fe–32Cu–9Ni–8Sn matrix mixture with diamond bits, both in absence and presence of nano-VN additives. It was demonstrated that without VN addition, the diamond–matrix interface contained voids and discontinuities. Nanodispersed VN added to the matrix resulted in the formation of a more fine-grained structure consisting of solid solutions composed of iron, copper, nickel, vanadium and tin in different ratios and the formation of a tight diamond–matrix zone with no visible voids, discontinuities and other defects. Optimal concentrations of VN in the CDM matrix were found achieving the maximum values of nanohardness H = 7.8 GPa, elastic modulus E = 213 GPa, resistance to elastic deformation expressed by ratio H/E = 0.0366, plastic deformation resistance H3/E2 = 10.46 MPa, ultimate flexural strength Rbm = 1110 MPa, and compressive strength Rcm = 1410 MPa. As-prepared Fe–Cu–Ni–Sn–VN composites with enhanced physical and mechanical properties are suitable for cutting tools of increased durability and improved performance.