A study of the structure and strength properties of the WC–Co drill insert with different CrB2 content sintered by vacuum hot pressing

Abstract

The optimal ratios of the components of the WC–Co‒CrB2 system have been established, at which a finely dispersed structure is formed with a simultaneous improvement in physical and mechanical properties. It is shown that the introduction of CrB2 (in concentration CCrB2 = 4% wt) leads to a twofold increase in fracture toughness (from KIc = 4.4 MPa ∙ m1/2 to KIc = 9.8 MPa ∙ m1/2) with a slight decrease hardness (from H = 15.1 to 13.9 GPa), as well as to an increase in the ultimate bending (from σ = 2000 to 2500 MPa) and compression (from σ = 5300 to 6000 MPa) strength of sintered composite specimens. Creation of the WC–Co‒CrB2 composite materials with improved mechanical and operational properties is essential for optimizing the designs of drilling tools for various technological purposes, increasing their reliability, energy saving, and improving operational properties. Keywords: composite; composition; concentration; structure; hardness; fracture toughness.