14 research outputs found
AlCoCrCuFeNi-Based High-Entropy Alloys: Correlation Between Molar Density and Enthalpy of Mixing in the Liquid State
The density of the liquid equiatomic high-entropy alloys, namely, AlCoCrCuFeNi, AlCoCuFeNi,
and CrCoCuFeNi, as well as quaternary alloys AlCoCuFe and AlCoCrNi was
determined over a wide temperature range. The measurements were performed by a non-contact
technique combining electromagnetic levitation and optical dilatometry. The temperature and
composition dependencies of the density were analyzed and the molar excess volumes were
calculated. The integral enthalpy of mixing of multi-component alloys was predicted using
extended Kohler model, while the model of Miedema was used for binary sub-system alloys. It has
been found that a negative excess volume of the investigated Al-containing liquid alloys
correlates with a negative enthalpy of mixing. In contrast, a positive excess volume and an
endothermic reaction have been estimated for the liquid CoCrCuFeNi alloy. The change of the
excess volume in the Al-containing liquid alloys is affected by two basic effects, namely,
compression of the Al matrix and formation of compounds in the melt