Vacancy effect on the preparation of high-entropy carbides

High-entropy carbides (HECs) are novel advanced materials composed of covalently bonded multicomponent transition metals and carbon. The transition metal atoms of all the precursor components are randomly distributed at the cation sublattice. Recently, a series of HECs with a non-stoichiometric comp...

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Bibliographic Details
Published in:Journal of materials science 2020-06, Vol.55 (16), p.6754-6760
Main Authors: He, Yu, Peng, Chong, Xin, Shengwei, Li, Kenan, Liang, Shuju, Lu, Xiaoqian, Kang, Ning, Xue, Hengxu, Shen, Xun, Shen, Tongde, Wang, Mingzhi
Format: Article
Language:English
Subjects:
Activation energy
Carbides
Carbon
Ceramics
Characterization and Evaluation of Materials
Chemistry and Materials Science
Classical Mechanics
Concentration gradient
Covalence
Crystallography and Scattering Methods
Diffusion
Entropy
Materials Science
Metal compounds
Nonstoichiometric compounds
Phase transitions
Polymer Sciences
Precursors
Solid Mechanics
Tantalum
Titanium
Transition metal alloys
Transition metal compounds
Tungsten carbide
Vacancies
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Summary:High-entropy carbides (HECs) are novel advanced materials composed of covalently bonded multicomponent transition metals and carbon. The transition metal atoms of all the precursor components are randomly distributed at the cation sublattice. Recently, a series of HECs with a non-stoichiometric compound (NSC) as one of the precursors have been synthesized. However, the effect of vacancies on the formation of HECs has not been addressed well. In this paper, NbC 0.5 was selected as the NSC to study the interfacial diffusion behavior of NbC 0.5 and other covalent transition metal compounds (MCs: M represents one of V, Ti, Ta, and W). The presence of vacancies resulted in a carbon concentration gradient, reduced the diffusion activation energy of metal atoms in NbC 0.5 –MC and increased the diffusion driving force. In addition, the diffusion process of WC in NbC 0.5 was analyzed. Phase transformation of WC to W 2 C was found during diffusion. The experiment proves that HECs may be easily prepared with the participation of the NSCs, and this work provides the theoretical basis for the alloying of covalent transition metal compounds.
ISSN:0022-2461
1573-4803
DOI:10.1007/s10853-020-04471-3