Three types of cBN-based composites with TaN binder—without whiskers, with Al2O3 whiskers, and with SiC whiskers—have been produced by the high

The results of thermodynamic modeling of superhard materials based on cubic boron nitride (cBN) with a tantalum nitride (TaN) binder and additions of alumi

High-purity, superhard, binderless polycrystalline cubic boron nitride (BL-PCBN) was obtained by direct hBN to cBN transformation in a toroid-type high-pressure apparatus at a pressure of 8.0 GPa and temperature of 2250 °C (HPHT-DCS; high-pressure, high-temperature direct conversion sintering). X-ray diffraction analysis revealed a prominent [111] axial texture in the sintered material when the axis was oriented perpendicular to the end surface of the sample. Vickers hardness tests conducted at a load of 49 N showed that BL-PCBN possessed an exceptional hardness value of 63.4 GPa. Finally, cutting tools made of BL-PCBN and SN-PCBN (Si₃N₄-doped cBN-based composite) reference materials were tested during the turning of a cemented tungsten carbide workpiece. The results of the cutting tests demonstrated that the wear resistance of the BL-PCBN material obtained with the HPHT-DCS process is 1.5–1.9 times higher compared to the conventional SN-PCBN material, suggesting its significant potential for industrial application.

This paper presents a comprehensive study of two tool materials designed for the machining of Inconel 718 superalloy, produced through two distinct sintering techniques: High Pressure–High Temperature (HPHT) sintering and Spark Plasma Sintering (SPS). The first composite (marked as BNT), composed of 65 vol% cubic boron nitride (cBN), was sintered from the cBN–TiN–Ti₃SiC₂ system using the HPHT technique at a pressure of 7.7 GPa. The second composite (marked as AZW) was fabricated from the Al₂O₃–ZrO₂–WC system using SPS at a pressure of 63 MPa. The final phase composition of BNT material differed significantly from the initial composition due to reactions occurred during sintering. In contrast, the phase composition of the AZW ceramic composite before and after sintering was similar. The materials exhibited high quality, as evidenced by a Young’s modulus of 580 GPa for BNT and 470 GPa for AZW, along with hardness of 26 GPa for BNT and 21 GPa for AZW. Both composites were used to prepare cutting inserts that were evaluated for their performance in machining Inconel 718 alloy. While both inserts showed durability comparable to their respective reference commercial inserts, they differed in performance and price relative to one another.

The structure, phase composition, and temperature dependence of electrical resistivity of the thermobarically sintered cBN–NbN composite are presente