The molybdenum effect on the structure and properties of the quasi-high-entropy alloy of the Fe-Co-Cr-Ni-Mn-Nb system

The results of the study of the effect of molybdenum on the structure and properties of the quasi-high-entropy alloy (QHEA) of the Fe-Co-Cr-Ni-Mn-Nb system are presented in this paper. Together with pure metals, ferroalloys were also used in smelting experimental alloys. Due to pure metals and ferroalloys, the obtained experimental alloys were called QHEA in contrast to HEA (high-entropy alloys). It was found that solid solutions of the FCC type (Mn, Fe, Co, Ni) and ICC type (Nb, Mo), σ-phase (Cr, Mo), carbides Cr3C7, (Nb, Mo)C and Laves phases (Nb, Mo)(Fe, Ni, Mn)2 were formed in the final structure of the studied samples. For the first time, the presence of such phases as carbides Cr3C7 and (Nb,Mo)C was established in the alloy structure, which were not described in similar studies devoted to the effect of molybdenum on the properties of alloys of the Fe-Co-Cr-Ni-Mn-Nb system. Adding Mo in 5-15% by weight increased the hardness from 243 HV to 689 HV and the strength from 550 MPa to 980 MPa without changing the ductility values.