Microstructure and mechanical properties of MoNbW(TaC)x composites

In this study, novel MoNbW(TaC)x composites with eutectic-like structures were firstly prepared by arc melting. The composites consisted of body-centered cubic (BCC) structured high entropy alloy (HEA) and face-centered cubic (FCC) structured carbide (Mo, Nb, Ta, W)C. During the solidification, eutectic reaction occurred in the composites to form eutectic structures of BCC phase and subcarbide (Mo, Nb, Ta, W)2C, and then the subcarbide decomposed into eutectoid structures of BCC phase and carbide (Mo, Nb, Ta, W)C. So the composites exhibited a new eutectic-like structures composed of BCC phase and fine nanoscale eutectoid structures. The MoNbW(TaC)0.9 composite with a fully eutectic-like microstructure exhibited ultimate compressive strength of 2779 ± 37 MPa. The MoNbW(TaC)0.5 composite showed the highest plastic strain of 10.80 ± 0.56% with the compressive strength of 1803 ± 33 MPa. The strengthening mechanisms of the composites are mainly the second phase strengthening and the grain refinement. [Display omitted] •Novel MoNbW(TaC)x composites with eutectic-like structure were synthesized.•Eutectoid structures consist of BCC phase and MC carbide with good phase interface.•Proper TaC addition strengthens and toughens MoNbW(TaC)x composites simultaneously.•MoNbW(TaC)0.9 has high compressive strength of 2779 MPa and plastic strain of 7.46%.•Strengthening mechanism is mainly second phase and fine grain strengthening.