Role of binder phase on the microstructure and mechanical properties of a mechanically alloyed and spark plasma sintered WC-FCC HEA composites

Abstract

Mechanical behavior of the binder phase in a ceramic-metal (cermet) composite is critical for its overall properties, especially toughness and shock resistance. High entropy alloys (HEA) are promising binder phase materials owing to their excellent mechanical properties and impact on obtaining fine-grain cermet microstructure. In the current work, Co27.4Cr13.8Fe27.4Ni27.4Mo4 HEA designed via ICME approach was used as a binder to fabricate ultrafine WC-HEA composite by mechanical alloying and spark plasma sintering. The effect of an HEA binder on the microstructure and mechanical properties of WC-HEA composite are discussed in terms of experimental observation and Weibull modulus (9.7). Compared to a commercial WC-Co composite, a WC-10 wt.% HEA composite exhibits higher hardness and fracture toughness of 21 GPa and 10.5 MPa m1/2, respectively.