Open AccessComputationally-driven engineering of sublattice ordering in a hexagonal AlHfScTiZr high entropy alloy
Author(s) -
Łukasz Rogal,
Piotr Bobrowski,
Fritz Körmann,
Sergiy V. Divinski,
Frank Stein,
Blazej Grabowski
Publication year - 2017
Publication title -
scientific reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.24
H-Index - 213
ISSN - 2045-2322
DOI - 10.1038/s41598-017-02385-w
Subject(s) - alloy , high entropy alloys , phase diagram , hexagonal crystal system , materials science , configuration entropy , entropy (arrow of time) , statistical physics , transmission electron microscopy , lattice (music) , intermetallic , thermodynamics , computer science , phase (matter) , crystallography , nanotechnology , physics , chemistry , metallurgy , quantum mechanics , acoustics
Multi-principle element alloys have enormous potential, but their exploration suffers from the tremendously large range of configurations. In the last decade such alloys have been designed with a focus on random solid solutions. Here we apply an experimentally verified, combined thermodynamic and first-principles design strategy to reverse the traditional approach and to generate a new type of hcp Al-Hf-Sc-Ti-Zr high entropy alloy with a hitherto unique structure. A phase diagram analysis narrows down the large compositional space to a well-defined set of candidates. First-principles calculations demonstrate the energetic preference of an ordered superstructure over the competing disordered solid solutions. The chief ingredient is the Al concentration, which can be tuned to achieve a D0 19 ordering on the hexagonal lattice. The computationally designed D0 19 superstructure is experimentally confirmed by transmission electron microscopy and X-ray studies. Our scheme enables the exploration of a new class of high entropy alloys.