Enhancement of high-temperature strength of cemented carbide by in-grain nanoparticles

Abstract

Achieving enhanced high-temperature strength in cemented carbides was challenging via conventional methods. This study presents a significant advancement in achieving superior high-temperature strength and strain in cemented carbides by introducing nanoparticles within WC grains. By utilizing the in-situ synthesized WC-Co composite powder as a raw material, the W-Co-C nanoparticles formed in the WC grains in the resultant cemented carbide. A comprehensive microstructural analysis on representative samples indicated the precipitated nanoparticles exhibited an average diameter of 4.4 nm and possessed coherent interfaces with the WC matrix. Uniaxial compression tests were conducted over the temperature rang from room temperature to 600 °C. It was demonstrated that the cemented carbides showed the highest compression strength and exceptional strain at 600 °C. The enhanced strain was attributed to the deformation accommodation of WC grains, induced by the generation and motion of high-density dislocations within the WC grains. The strength enhancement originated from effective interactions between dislocations and nanoparticles. In particular, the shearing resistance between dislocations and nanoparticles creates a strengthening effect by impeding dislocation motion in the WC matrix. This work provides a new approach for improving the integrated mechanical properties of cemented carbides at high temperatures by enhancing the ceramic phase.