View in EDS

Tailoring structural, mechanical, and electronic properties of (Ti0.25Ta0.25Zr0.25Nb0.25-xLax)C high-entropy carbide ceramics via rare-earth La incorporation: A comprehensive first-principles study.

Saved in:
Bibliographic Details
Title: Tailoring structural, mechanical, and electronic properties of (Ti0.25Ta0.25Zr0.25Nb0.25-xLax)C high-entropy carbide ceramics via rare-earth La incorporation: A comprehensive first-principles study.
Authors: Wang, Zhipeng1,2 (AUTHOR) wangzp1205@hnu.edu.cn, Yu, Zhaowen1 (AUTHOR), Zhang, Linkun3 (AUTHOR), Liu, Feng3 (AUTHOR), Huang, Lan3 (AUTHOR), Wang, Yan3 (AUTHOR), Tan, Liming3 (AUTHOR), Wang, Zi1,3 (AUTHOR) wangzi@csu.edu.cn, Ma, Li4 (AUTHOR), Tang, Pingying4 (AUTHOR)
Source: Ceramics International. Sep2025:Part A, Vol. 51 Issue 21, p33721-33730. 10p.
Subjects: Dislocation nucleation, Shear (Mechanics), Electron delocalization, Heat of formation, Vickers hardness
Abstract: High-entropy carbide ceramics (HECCs) exhibit exceptional material properties, but their underlying physical mechanisms are underexplored. This study utilizes first-principles calculations to examine the influence of rare-earth La on the structural, mechanical, dislocation, and electronic properties of (Ti 0.25 Ta 0.25 Zr 0.25 Nb 0.25- x La x)C (x = 0∼18.75 %) HECCs. Key parameters, including formation enthalpy, lattice distortion, elastic constants, mechanical modulus, and density of states, are systematically analyzed as a function of La content. Results show that La preferentially substitutes Nb sites, forming thermodynamically stable rock-salt structures. Increased La content induces severe lattice distortion, reduces resistance to bulk, elastic, and shear deformation, and enhances ductility while decreasing brittleness. La incorporation also lowers Vickers hardness and yield strength, weakening crack resistance. Notably, (Ti 0.25 Ta 0.25 Zr 0.25 Nb 0.0625 La 0.1875)C exhibits minimal energy factors and maximum dislocation width, facilitating dislocation nucleation and twinning. A rightward shift and reduced peak heights in valence band of total density of states curves with increasing La content indicate enhanced electron delocalization and reduced brittleness. These findings highlight the potential of La substitution to tailor structural, mechanical, and electronic properties in (Ti 0.25 Ta 0.25 Zr 0.25 Nb 0.25- x La x)C HECCs, offering insights for designing ductile HECCs. [ABSTRACT FROM AUTHOR]
Copyright of Ceramics International is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: Engineering Source
Description
Abstract:High-entropy carbide ceramics (HECCs) exhibit exceptional material properties, but their underlying physical mechanisms are underexplored. This study utilizes first-principles calculations to examine the influence of rare-earth La on the structural, mechanical, dislocation, and electronic properties of (Ti 0.25 Ta 0.25 Zr 0.25 Nb 0.25- x La x)C (x = 0∼18.75 %) HECCs. Key parameters, including formation enthalpy, lattice distortion, elastic constants, mechanical modulus, and density of states, are systematically analyzed as a function of La content. Results show that La preferentially substitutes Nb sites, forming thermodynamically stable rock-salt structures. Increased La content induces severe lattice distortion, reduces resistance to bulk, elastic, and shear deformation, and enhances ductility while decreasing brittleness. La incorporation also lowers Vickers hardness and yield strength, weakening crack resistance. Notably, (Ti 0.25 Ta 0.25 Zr 0.25 Nb 0.0625 La 0.1875)C exhibits minimal energy factors and maximum dislocation width, facilitating dislocation nucleation and twinning. A rightward shift and reduced peak heights in valence band of total density of states curves with increasing La content indicate enhanced electron delocalization and reduced brittleness. These findings highlight the potential of La substitution to tailor structural, mechanical, and electronic properties in (Ti 0.25 Ta 0.25 Zr 0.25 Nb 0.25- x La x)C HECCs, offering insights for designing ductile HECCs. [ABSTRACT FROM AUTHOR]
ISSN:02728842
DOI:10.1016/j.ceramint.2025.05.107