First-principles study, fabrication and characterization of (Zr0.25Nb0.25Ti0.25V0.25)C high-entropy ceramics
- South China Univ. of Technology (SCUT), Guangzhou (China)
- Northwestern Polytechnical Univ., Xi'an (China); Ames Lab., Ames, IA (United States)
- Ames Lab., Ames, IA (United States)
- Northwestern Polytechnical Univ., Xi'an (China)
- Ames Lab., Ames, IA (United States); Iowa State Univ., Ames, IA (United States)
The formation possibility of a new (Zr0.25Nb0.25Ti0.25V0.25)C high-entropy ceramics (ZHC-1) was first analyzed by the first-principles calculations and thermodynamical analysis and then it was successfully fabricated by hot pressing sintering technique. The first-principles calculation results showed that the mixing enthalpy of ZHC-1 was 5.526 kJ/mol and the mixing entropy of ZHC-1 was in the range of 0.693R–1.040R. The thermodynamical analysis results showed that ZHC-1 was thermodynamically stable above 959 K owing to its negative mixing Gibbs free energy. The experimental results showed that the as-prepared ZHC-1 (95.1% relative density) possessed a single rock-salt crystal structure, some interesting nano-plate-like structures, and high compositional uniformity from nanoscale to microscale. By taking advantage of these unique features, compared with the initial metal carbides (ZrC, NbC, TiC and VC), it showed a relatively low thermal conductivity of 15.3 ± 0.3 W/(m·K) at room temperature, which was due to the presence of solid solution effects, nanoplates and porosity. Meanwhile, it exhibited the relatively high nanohardness of 30.3 ± 0.7 GPa and elastic modulus of 460.4 ± 19.2 GPa and the higher fracture toughness of 4.7 ± 0.5 MPam1/2, which were attributed to the solid solution strengthening mechanism and nanoplate pullout and microcrack deflection toughening mechanism.
- Research Organization:
- Ames Lab., Ames, IA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division; USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- 2017YFB0703200; 51802100; 2017QNRC001; AC02-07CH11358
- OSTI ID:
- 1556116
- Alternate ID(s):
- OSTI ID: 1527144; OSTI ID: 1637034
- Report Number(s):
- IS-J-9930
- Journal Information:
- Acta Materialia, Vol. 170, Issue C; ISSN 1359-6454
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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