MICROSTRUCTURE AND MECHANICAL PROPERTIES OF ULTRAFINE WC/Co CEMENTED CARBIDES WITH CUBIC BORON NITRIDE AND Cr₃C₂ ADDITIONS

This study investigates the microstructure and mechanical properties of ultrafine tungsten carbide and cobalt (WC/Co) cemented carbides with cubic boron nitride (CBN) and chromium carbide (Cr 3 C 2 ) fabricated by a hot pressing sintering process.This study uses samples with 8 wt.% Co content and 7.5 vol.% CBN content, and with different Cr 3 C 2 content ranging from 0 to 0.30 wt.%.Based on the experimental results, Cr 3 C 2 content has a significant influence on inhibiting abnormal grain growth and decreasing grain size in cemented carbides.Near-full densification is possible when CBN-WC/Co with 0.25 wt.% Cr 3 C 2 is sintered at 1350°C and 20 MPa; the resulting material possesses optimal mechanical properties and density, with an acceptable Vickers hardness of 19.20 GPa, fracture toughness of 8.47 MPa•m 1/2 and flexural strength of 564 MPa.60 (1) 85-90 (2016) Ceramics -Silikáty