The effects of temperature and pressure on the physical properties and stabilities of point defects and defect complexes in B1-ZrC

Yang, Guanlin; Xiong, Meiling; Zhou, Yulu; Tao, Xinyong; Peng, Qing; Ouyang, Yifang

doi:10.1016/j.commatsci.2021.110694

Cited by 6 publications

(3 citation statements)

References 55 publications

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“…A similar effect was observed by Zhao et al [ 26 ] in pressureless sintering of ZrC with carbon and silicon used as sintering aids to form a ZrC-SiC alloy. Four ZrC starting powders were employed: (1) As-received ZrC, (2) ball-milled ZrC (MZ), (3) ZrC + 2 wt % graphite (ZC), and (4) ZrC + 20 vol % SiC (ZS).…”

Section: Discussionsupporting

confidence: 80%

“…This ultimately will lead to stress concentration and early failure of the material. Compounding the mechanical concerns, if the interstitial species are reactive, these defects could result in degradation of the chemical stability and oxidation behavior of ZrC, negatively impacting the expected performance of ZrC as an aerospace material [ 26 ].…”

Section: Introductionmentioning

confidence: 99%

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Zirconium Carbide for Hypersonic Applications, Opportunities and Challenges

Peterson,

Carr,

Marinero

2023

Materials

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At ultra-high temperatures, resilient, durable, stable material choices are limited. While Carbon/Carbon (C/C) composites (carbon fibers and carbon matrix phases) are currently the materials of choice, zirconium carbide (ZrC) provides an option in hypersonic environments and specifically in wing leading edge (WLE) applications. ZrC also offers an ultra-high melting point (3825 K), robust mechanical properties, better thermal conductivity, and potentially better chemical stability and oxidation resistance than C/C composites. In this review, we discuss the mechanisms behind ZrC mechanical, thermal, and chemical properties and evaluate: (a) mechanical properties: flexure strength, fracture toughness, and elastic modulus; (b) thermal properties: coefficient of thermal expansion (CTE), thermal conductivity, and melting temperature; (c) chemical properties: thermodynamic stability and reaction kinetics of oxidation. For WLE applications, ZrC physical properties require further improvements. We note that materials or processing solutions to increase its relative density through sintering aids can have deleterious effects on oxidation resistance. Therefore, improvements of key ZrC properties for WLE applications must not compromise other functional properties. We suggest that C/C-ZrC composites offer an engineering solution to reduce density (weight) for aerospace applications, improve fracture toughness and the mechanical response, while addressing chemical stability and stoichiometric concerns. Recommendations for future work are also given.

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Section: Discussionsupporting

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Zirconium Carbide for Hypersonic Applications, Opportunities and Challenges

Peterson,

Carr,

Marinero

2023

Materials

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“…Both types of interstitials have been reported in transition-metal nitrides [ 14 , 15 , 16 , 17 ] and transition-metal carbides [ 18 , 19 , 20 ], with tetrahedral sites having been considered more frequently in previous studies [ 21 , 22 , 23 , 24 , 25 ].The N <110> split interstitial is preferred over the tetrahedral interstitial sites in TiN [ 14 , 15 ], ScN [ 14 ], YN [ 14 ], LaN [ 14 ], VN [ 14 ], and MoN [ 14 ] and the <111> split interstitial in CrN [ 14 ] and WN [ 14 ]. In contrast, the tetrahedral site is the preferred configuration in TiC [ 18 , 20 ], ZrC [ 19 ], ZrN [ 14 ], HfN [ 14 ], NbN [ 14 ], and TaN [ 14 ].…”

Section: Introductionmentioning

confidence: 99%

A Novel Interstitial Site in Binary Rock-Salt Compounds

Mishra

Makov

2022

Materials

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The energetic and mechanical stability of interstitial point defects in binary rock-salt materials were studied using the first-principles method. A novel, stable, and energetically competitive interstitial site (base-interstitial) was identified for anion interstitials in rock-salts. The formation energies of base-interstitial defects were compared with well-explored tetrahedral (body-interstitial) and split interstitials and were found to be energetically highly competitive. For alkali halides and silver bromide, the lowest formation energies are associated with the base-interstitial site and the <110> split interstitial, which are therefore the predominant interstitial sites. However, split interstitials were found to be the energetically preferred configuration in metal monochalcogenide systems. Electronic band structures are affected by the presence of interstitial defects in rock-salt structures. In particular, the Fermi level is shifted below the valence band maxima for the body, base, and split interstitials in metal halides, indicating p-type conductivity. However, the Fermi level remains within the bandgap for metal monochalcogenides, indicating no preferred conductivity for base- and split-interstitial defects. Allowing the defects to be charged changes the relative stability of the interstitial sites. However, the new base-interstitial site remains preferred over a range of potentials for alkali halides. The anion base-interstitial is found to form a triatomic entity with the nearest lattice anions that affect the electronic structure relative to the body interstitial. The discovery of a new interstitial site affects our understanding of defects in binary rock-salts, including structure and dynamics as well as associated thermodynamic and kinetic properties that are interstitial dependent.

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