Development of cemented carbides with CoxFeNiCrCu high-entropy alloyed binder prepared by spark plasma sintering

Abstract

Cemented carbides is widely used in industrial fields, but it is difficult to meet the needs of the evolving modern industry due to the shortage of cobalt resources and the difficulty to balance hardness and toughness. In order to solve this problem, a high-entropy alloys (HEA) as the novel binder were used to fabricate WC-10CoxFeNiCrCu (x = 1, 1.5, 2, 2.5) cemented carbides. CoxFeNiCrCu (x = 1, 1.5, 2, 2.5) HEA powders were prepared by mechanically alloying and powder mixes of WC and the HEA were obtained by high energy ball-milling. Spark plasma sintering (SPS) was used to fabricate the WC-10HEA cemented carbides. Effects of Co content in the HEA binder and sintering temperature (1300 °C, 1350 °C, 1400 °C, 1450 °C) on the microstructure and properties of the resultant WC-10HEA cemented carbides were investigated. After SPS sintering at 1400 °C and 30 MPa for 8 min, the WC-10CoxFeNiCrCu cemented carbides had finer grain size and better mechanical properties then the conventional cemented carbides with cobalt as binder. The cemented carbides with Co1.5FeNiCrCu as binder had average WC grain size about 398(±67.94) nm, and Vickers hardness up to 2078.2 (±40.35) MPa and the fracture toughness was 11.636(±0.1) MPa∙m1/2. The present work indicates that HEA has the potential to replace conventional Co as a new binder, because of its finer grain and high hardness.