Effect of ultrafine WC contents on the microstructures, mechanical properties and wear resistances of regenerated coarse grained WC-10Co cemented carbides

Abstract

The effects of ultrafine WC content on the microstructure, mechanical properties and wear resistance of regenerated coarse grained WC-10Co cemented carbides have been investigated by SEM, mechanical property tests and wear test. The results show that with the increase of ultrafine WC content, the average grain size of the regenerated cemented carbides increases first and then decreases. When the ultrafine WC content is 10%, the average grain size of the regenerated cemented carbides is the maximum (4.06 μm). Meanwhile, the irregular shape grain decreases and the growth of grain is improved. When the ultrafine WC content is 10%, the regenerated cemented carbides have the highest density (99.84%), which could alleviate the negative impact of coarse grains on hardness. The transverse rupture strength and fracture toughness of regenerated cemented carbides increases on account of crack deflection, crack branching, crack bridging, the increase of transgranular fracture of WC and dimple fracture of Co phase (TRS: 2520 MPa, KIC: 20.28 MPa·m1/2). Therefore, when the ultrafine WC content is 10%, the regenerated cemented carbides have more optimal mechanical properties. The addition of ultrafine WC particles balances the hardness and fracture toughness of the regenerated cemented carbides in the sliding wear experiment, which is found that the friction coefficient, wear rate, wear scar width and depth of regenerated cemented carbides are the smallest when the content of ultrafine WC is 15%.