High-entropy alumino-silicides: a novel class of high-entropy ceramics

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  • ReceivedJul 13, 2019
  • AcceptedAug 14, 2019
  • PublishedSep 19, 2019


High-entropy ceramics (HECs) are gaining significant interest due to their huge composition space, unique microstructure, and adjustable properties. Previously reported studies focus mainly on HECs with the multi-cationic structure, while HECs with more than one anion are rarely studied. Herein we reported a new class of HECs, namely high-entropy alumino-silicides (Mo0.25Nb0.25Ta0.25V0.25)(Al0.5Si0.5)2 (HEAS-1) with multi-cationic and -anionic structure. The formation possibility of HEAS-1 was first theoretically analyzed from the aspects of thermodynamics and lattice size difference based on the first-principles calculations and then the HEAS-1 were successfully synthesized by the solid-state reaction at 1573 K. The as-synthesized HEAS-1 exhibited good single-crystal hexagonal structure of metal alumino-silicides and simultaneously possessed high compositional uniformity. This study not only enriches the categories of HECs but also will open up a new research field on HECs with multi-cationic and -anionic structure.

Funded by

the National Key Research and Development Program of China(2017YFB0703200)

Young Elite Scientists Sponsorship Program by China Association for Science and Technology(2017QNRC001)

and the National Natural Science Foundation of China(51802100)


This work was supported by the National Key Research and Development Program of China (2017YFB0703200), Young Elite Scientists Sponsorship Program by China Association for Science and Technology (2017QNRC001), and the National Natural Science Foundation of China (51802100 and 51972116).

Interest statement

The authors declare that they have no conflict of interest.

Contributions statement

Chu Y conceived and designed the experiments. Chu Y and Liu H performed the experiments. Chu Y, Wen T, Liu H, Ye B and Liu D analyzed the data. Wen T performed the first-principles calculations. All authors commented on the manuscript.

Author information

Tongqi Wen is currently a PhD student at Northwestern Polytechnical University and jointly supervised in Ames laboratory, USA and South China University of Technology. His research interests include computational modeling, crystal structure prediction and materials discovery.

Honghua Liu is currently a Master student at South China University of Technology. His research focuses on the fabrication and characterization of high-entropy ceramics and related powders.

Yanhui Chu is as an associate professor at South China University of Technology. He received his PhD degree in materials science from Northwestern Polytechnical University in 2016. From January 2014 to August 2015, he was a visiting scholar at Harvard University. His current research interests include high-temperature coatings, high-entropy ceramics and related nanomaterials.


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  • Figure 1

    A simple schematic illustration of the atomic structure that does not take the lattice distortion into account of HEAS-1. (a) and (b) are two alternative views of the hexagonal unit cell showing the ABC stacking sequences.

  • Figure 2

    (a) Thermodynamics analysis of the possible chemical reactions during HEAS-1 synthesis process; (b) XRD patterns: A is for the as-synthesized product and B is for the mixture of the starting materials.

  • Figure 3

    SEM and TEM analysis of the as-synthesized HEAS-1. (a) SEM image; (b) TEM image; (c) SAED pattern; (d) HRTEM image; (e) STEM image and corresponding EDS compositional maps.

  • Table 1   Calculated equilibrium lattice parameters, space group and DFT energies of the ground-state crystal structures of different elementary substances








    Lattice parameters a (Å)







    Space group







    Energies E (eV atom−1)







  • Table 2   Calculated equilibrium lattice parameters, DFT energies, mixing enthalpy, mixing entropy, and the lattice size difference of the generated HEAS-1 and four individual metal alumino-silicides at and by chemical reaction ()







    Lattice parameter a (Å)






    Lattice parameter c (Å)






    Energies E(eV atom−1)






    Mixing enthalpy ΔHmix(n) (kJ mol−1)

    1.616 (n=6) −32.285 (n=7)

    −36.664 (n=2)

    −37.221 (n=3)

    −31.454 (n=4)

    −30.264 (n=5)

    Mixing entropy


    0.462R (n=6) 0.924R (n=7)

    0.462R (n=2)

    0.462R (n=3)

    0.462R (n=4)

    0.462R (n=5)

    Lattice size difference δ (%)






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