Cooling rate control combined with refractory Mo and/or V addition to enhance the mechanical properties of CoCrFeMnNi alloy

This work shows that optimum combination of cooling rate control and refractory Mo and/or V element addition to the CoCrFeMnNi (Cantor) HEA enables to develop novel high-strength hierarchical microstructures consisting of FCC, σ phase and finely dispersed precipitates obtained through . This has been achieved by casting developing CoCrFeMnNiV 0.5 , CoCrFeMnNiMo 0.5 and CoCrFeMnNiV 0.5 Mo 0.5 at. % HEAs casted at a cooling rate of ∼ 1000 K/s. Since this cooling rate is relatively fast, it enables to retain the Mo and/or V alloying elements in solid solution in the FCC phase. The phenomenon of solid solution hardening contributes to a decrease in the maximum indentation depth from 100 μm for CoCrFeMnNi, to ∼89 μm and ∼ 85 μm for the FCC and σ phases, respectively in the CoCrFeMnNiV 0.5 Mo 0.5 at. % HEA. The novel microstructures additionally improve the wear resistance, particularly regarding the scratch hardness number, from H s = 2.74 GPa for CoCrFeMnNi, to 4.19 GPa for CoCrFeMnNiV 0.5 , 4.78 GPa for CoCrFeMnNiMo 0.5 and 6.85 GPa for CoCrFeMnNiMo 0.5 V 0.5 thus making these alloys of potential interest for engineering components subjected to load and wear.