Hydrogen quantum effects in hydride LaNi5H7J. Appl. Phys. 110, 063533 (2011) Accurate determination of the Gibbs energy of Cu-Zr melts using the thermodynamic integration method in Monte Carlo simulations J. Chem. Phys. 135, 084502 (2011) Efficient calculation of -and -nitrogen free energies and coexistence conditions via overlap sampling with targeted perturbation J. Chem. Phys. 135, 044125 (2011) An incremental mean first passage analysis for a quasistatic model of polymer translocation through a nanopore J. Chem. Phys. 134, 154905 (2011) The effect of pressure on the phase transition behavior of tridecane, pentadecane, and heptadecane: A Fourier transform infrared spectroscopy study J. Chem. Phys. 134, 144503 (2011) Additional information on J. Appl. Phys. Phase stability is an important topic for high entropy alloys (HEAs), but the understanding to it is very limited. The capability to predict phase stability from fundamental properties of constituent elements would benefit the alloy design greatly. The relationship between phase stability and physicochemical/thermodynamic properties of alloying components in HEAs was studied systematically. The mixing enthalpy is found to be the key factor controlling the formation of solid solutions or compounds. The stability of fcc and bcc solid solutions is well delineated by the valance electron concentration (VEC). The revealing of the effect of the VEC on the phase stability is vitally important for alloy design and for controlling the mechanical behavior of HEAs.

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High-entropy alloys (HEAs) can have either high strength or high ductility, and a simultaneous achievement of both still constitutes a tough challenge. The inferior castability and compositional segregation of HEAs are also obstacles for their technological applications. To tackle these problems, here we proposed a novel strategy to design HEAs using the eutectic alloy concept, i.e. to achieve a microstructure composed of alternating soft fcc and hard bcc phases. As a manifestation of this concept, an AlCoCrFeNi2.1 (atomic portion) eutectic high-entropy alloy (EHEA) was designed. The as-cast EHEA possessed a fine lamellar fcc/B2 microstructure, and showed an unprecedented combination of high tensile ductility and high fracture strength at room temperature. The excellent mechanical properties could be kept up to 700°C. This new alloy design strategy can be readily adapted to large-scale industrial production of HEAs with simultaneous high fracture strength and high ductility.

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This paper summarises existing phase selection rules for cast high entropy alloys. Essentially, they are almost all based on the parametric approach, utilising various descriptors comprising mixing enthalpy, configuration entropy, mismatch entropy, melting points, atomic size mismatch, electronegativity and valence electron concentration. The overview starts from phase selection rules for solid solutions, intermetallic compounds and the amorphous phase in high entropy alloys. Further discussions are relevant to selection rules for solid solution phases in high entropy alloys, more specifically, for face centred cubic and body centred cubic type solid solutions. Finally, some challenges and future prospects of phase selection rules for high entropy alloys are addressed.