From diluted solid solutions to high entropy alloys: On the evolution of properties with composition of multi-components alloys

Overview & Synopsis

To study the evolution of structural and mechanical properties with composition, 10 CrxMnxFexCoxNi100-4x alloys were processed and characterized by X-ray diffraction and nanoindentation. Those alloys are all single-phase solid-solutions and their composition ranges from conventional diluted multi-component alloys (MCA) to high entropy alloys (HEA). The lattice parameter and the hardness were measured and were compared to existing models. The hardest studied alloy turns out to be the non-equimolar Cr10Mn10Fe10Co10Ni60. More precisely, it was shown that, when the composition evolves from diluted MCA to HEA: (i) the lattice parameter increases and follows a Vegard’s law up to 4x = 40 at. %; (ii) the hardness increases and follows a Mott-Nabarro-Labush law up to 4x = 40 at. % and then decreases. This breakpoint of the evolution of both lattice parameter and hardness at 40 at. % is proposed as the transition between conventional diluted multi-component solid solutions and HEA.