Alloys with adjustable mechanical performance are of fundamental interest in material designs. Here, we investigate the magnetic- and chemical-ordering behavior of the ferromagnetic $\mathrm{Fe}\text{−}\mathrm{Cr}\text{−}\mathrm{Co}\text{−}\mathrm{Ni}\text{−}{\mathrm{Al}}_x$ $(1\le x\le 2.5)$ high-entropy alloys with the help of first-principle alloy theory. The lattice constants and the single- and polycrystalline elastic parameters for partially ordered and random structures are considered. In contrast to the trend found for the completely disordered phase, we demonstrate that ordering driven primarily by $\mathrm{Al}$ results in an enhanced Young’s modulus, especially at high-$\mathrm{Al}$ concentrations, which is in line with the observed increase of the hardness for systems with a body-centered-cubic underlying lattice. The results suggest that outstanding strength and ductility can be realized by proper control of the ordering level in single- and multiphase high-entropy alloys.

• Received 6 September 2017
• Revised 23 August 2018

DOI:https://doi.org/10.1103/PhysRevApplied.10.064033