High-Entropy-Alloy Binder for TiC-Based Cemented Carbide by SHS Method

International audienceHigh-entropy alloys represent a new class of materials exhibiting attractive physicomechanical properties [1, 2]. A basic idea is that five or more various atoms are capable of forming a simple (fcc of bcc) crystal lattice of single-phase alloy. Exceptional properties of such alloys are associated with their high configura-tional entropy. Of utmost interest is the so-called Can-tor alloy CoCrFeNiMn [3] that shows high fracture resistance at cryogenic temperatures [4, 5], high tensile properties and ductility [6-9], superplasticity [10], and good hardness and strength [8, 11, 12]. Recently, high-entropy alloys were used as a binder for cemented carbides [13, 14]. In this communication, we report on the one-step preparation of high-entropy-alloy binder CoCrFeNiMn for TiC-based cemented carbide (two in one) by SHS method. In combustion experiments, we used the following green compositions: where x was varied between 0.0 and 1.0. Mass fraction of CoCrFeNiMn binder (m b) was defined by the expression Preliminary thermodynamic calculations have shown (Fig. 1) that T ad gradually decreases with increasing m b and that SHS reaction is only possible when T ad exceeds the melting point of Ti. The latter holds true for m b < 55 wt %. At higher m b , combustion synthesis can be conducted in a mode of thermal explosion or reactive sintering. Commercial powders of Ti (PTM brand, particle size 2-100 μm), carbon black (P-803,