Irradiation damage in (Zr0.25Ta0.25Nb0.25Ti0.25)C high-entropy carbide ceramics

Wang, Fei; Yan, Xueliang; Wang, Tianyao; Wu, Yaqiao; Shao, Lin; Nastasi, M.; Lu, Yongfeng; Cui, Bai

doi:10.1016/j.actamat.2020.06.011

Cited by 187 publications

(82 citation statements)

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“…Investigations on HEAs revealed that the unique combination of superior mechanical properties, corrosion resistance, irradiation tolerance made them promising for nuclear applications [199][200][201][202]. Motivated by the achievement in HEAs, the irradiation effects of high-entropy carbides were also investigated [169,203]. In contrast to ZrC, which is characterized by structural swelling (i.e., lattice parameter expansion) after neutron, proton, and ion irradiation [204], after 120 keV helium ion irradiation at 25 ℃, the coalescence of helium bubbles was significantly suppressed in (Hf 0.2 Zr 0.2 Ta 0.2 Nb 0.2 Ti 0.2 )C [203].…”

Section: Irradiation Resistancementioning

confidence: 99%

“…Motivated by the achievement in HEAs, the irradiation effects of high-entropy carbides were also investigated [169,203]. In contrast to ZrC, which is characterized by structural swelling (i.e., lattice parameter expansion) after neutron, proton, and ion irradiation [204], after 120 keV helium ion irradiation at 25 ℃, the coalescence of helium bubbles was significantly suppressed in (Hf 0.2 Zr 0.2 Ta 0.2 Nb 0.2 Ti 0.2 )C [203]. Wang et al [169] further investigated the irradiation damage of (Zr 0.25 Ta 0.25 Nb 0.25 Ti 0.25 )C. Through irradiation of 3 MeV Zr ions to 20 dpa at 25, 300, and 500 ℃, the rock-salt structure was maintained without phase transformation or amorphous formation, indicating good phase stability of (Zr 0.25 Ta 0.25 Nb 0.25 Ti 0.25 )C. About ~0.2% lattice expansion was revealed through XRD analysis.…”

Section: Irradiation Resistancementioning

confidence: 99%

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High-entropy ceramics: Present status, challenges, and a look forward

et al. 2021

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High-entropy ceramics (HECs) are solid solutions of inorganic compounds with one or more Wyckoff sites shared by equal or near-equal atomic ratios of multi-principal elements. Although in the infant stage, the emerging of this new family of materials has brought new opportunities for material design and property tailoring. Distinct from metals, the diversity in crystal structure and electronic structure of ceramics provides huge space for properties tuning through band structure engineering and phonon engineering. Aside from strengthening, hardening, and low thermal conductivity that have already been found in high-entropy alloys, new properties like colossal dielectric constant, super ionic conductivity, severe anisotropic thermal expansion coefficient, strong electromagnetic wave absorption, etc., have been discovered in HECs. As a response to the rapid development in this nascent field, this article gives a comprehensive review on the structure features, theoretical methods for stability and property prediction, processing routes, novel properties, and prospective applications of HECs. The challenges on processing, characterization, and property predictions are also emphasized. Finally, future directions for new material exploration, novel processing, fundamental understanding, in-depth characterization, and database assessments are given.

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Section: Irradiation Resistancementioning

confidence: 99%

Section: Irradiation Resistancementioning

confidence: 99%

High-entropy ceramics: Present status, challenges, and a look forward

et al. 2021

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“…Compared to conventional ceramics, HECs exhibit particular physical properties, such as low thermal conductivity, 6 high nanohardness, 18,19 good oxidation resistance, 5 and outstanding irradiation resistance 20 . Notably, under ion irradiation, the coalesce and growth of defect clusters are strongly suppressed in a (Nb 0.25 Ta 0.25 Ti 0.25 Zr 0.25 )C HEC, which is assumed as the result of the severer lattice distortion, thanks to the high‐entropy effects 20 . The lattice distortion in some HECs has been reported before 21–23 .…”

Section: Introductionmentioning

confidence: 99%

“…Among all the reported HECs, high‐entropy carbides have been intensively investigated due to their potentials for high‐temperature applications. Currently, the experimentally discovered single‐phase HEC carbides include (Nb 0.33 Ta 0.33 Zr 0.33 )C, 19 (Nb 0.25 Ta 0.25 Ti 0.25 Zr 0.25 )C, 20 (Nb 0.25 Ti 0.25 V 0.25 Zr 0.25 )C, 27 (Hf 0.25 Nb 0.25 Ta 0.25 Zr 0.25 )C, 7,28,29 (Hf 0.2 Nb 0.2 Ta 0.2 Ti 0.2 Zr 0.2 )C, 5–7 (Mo 0.2 Nb 0.2 Ta 0.2 V 0.2 W 0.2 )C, 26 and other five‐metal carbide systems 18,26,30 . These HEC carbides possess rock salt structures, with the cation positions occupied randomly by several refractory metal elements at an equal atomic ratio, and the anion positions occupied completed by C. The cations and anions form two FCC sublattices in the structures.…”

Section: Introductionmentioning

confidence: 99%

Lattice distortion in high‐entropy carbide ceramics from first‐principles calculations

Zhao

2021

J Am Ceram Soc

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The idea of high‐entropy alloys (HEAs) has profoundly stimulated the recent development of novel entropy‐stabilized ceramics. Herein we explore the local lattice distortion, one of the core effects in HEAs responsible for their extraordinary properties, in typical high‐entropy ceramic (HEC) carbides with single‐phase rock salt structures. We first quantify the local distortions based on first‐principles calculations, and then investigate their influences on the structural properties, lattice stability, electronic structures, mechanical deformation, defect energetics, and thermodynamic properties. Our results show that carbon generally exhibits the most substantial distortion. On average, large local distortion is found in (NbTiVZr)C and (MoNbTaVW)C. Such distortion plays a crucial role in stabilizing HECs by lowering their enthalpy of formation. The electronic structure of HECs depends strongly on the local distortion, which can enhance charge transfer between transition metals and carbon atoms. We further show that distortion makes HECs soft and ductile due to the delocalization of electronic charges. The formation energies of C vacancies decrease significantly due to local distortion, resulting in high concentrations of C vacancies. The presence of high‐concentration C vacancies release distortion and helps to retain the high strength of HECs. Finally, we show that lattice distortion has a great impact on the thermodynamic quantities of HECs, such as thermal expansion coefficient and Debye temperature.

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“…高熵概念来源于高熵合金，它以多元组分固溶来增加构型熵从而获得固溶体相结构上的稳定。高熵会带来热力学上的高熵效应、结构上的晶格畸变效应、动力学上的迟滞扩散效应以及性能上的"鸡尾酒"效应 [1] ，将高熵概念引入到陶瓷材料的研究已受到越来越多的关注。自 2015 年 Rost 等 [2] 发现(MgNiCoCuZn)O 高熵氧化物陶瓷中熵能驱动多相和单相之间的可逆变化之后，高熵氧化物 [3][4][5][6][7] 、高熵硼化物 [8][9][10][11] 、碳化物 [12][13][14][15] 、硅化物 [16][17][18] 、MAX 相 [19][20] 、阴离子高熵陶瓷 [21] 及高熵陶瓷基复合材料 [22][23][24][25] 等相关研究陆续被报道。过渡金属碳化物和硼化物具有高熔点、高硬度、优异的高温力学性能和化学稳定性，被广泛应用于航空航天领域 [26][27][28] ，并在核工业领域具有良好的应用前景 [29][30] 。面对高温、高应力、强辐照和强腐蚀等极端工作环境对性能的要求，通过高熵设计来提高陶瓷材料的性能是目前研究的热点。有研究报导，高熵碳化物(TaHfZrNb)C 陶瓷在高温(1400 ℃和 1600 ℃)下的稳态蠕变速率约为其中任意组成元素的二元碳化物陶瓷 90%，具有更高的抗高温蠕变特性 [31] 。高熵碳化物(HfTaZrNb)C 陶瓷 [32] 以及高熵二硼化物 (HfZrTaCrTi)B2 、 (HfMoZrNbTi)B2 、 (HfMoTaNbTi)B2 陶瓷都表现出比其组成元素的二元化合物更高的硬度 [33] 。高熵碳化物 (ZrTaNbTi)C 陶瓷用 20dpa 剂量的 3 MeV Zr 离子辐照后，仍能保持晶格完整，晶胞膨胀仅 0.2%，具有良好的抗辐照损伤特性 [34] 。然而高熵碳化物(HfZrTaNbTi)C 由于阳离子亚晶格扭曲，增强了声子散射，导致其热导率低于其组元的二元碳化物 [35] 。高熵带来的性能提升或下降与其引起的微纳结构变化有着十分密切的关系。透射电子显微镜(TEM)能够在纳米及原子尺度给出材料的结构、元素分布和价态信息，这有助于深刻理解高熵固溶结构的形成机制以及结构与性能之间的内在关系。Zhang 等 [36] 利用 TEM 高分辨像在三元合金 CrCoNi 中发现了短程有序结构，短程有序结构可以增大层错能并提高硬度。 Lei 等 [37] 利用球差校正透射电子显微镜 (ACTEM) 的环形明场像 (ABF) 在高熵合金 TiZrHfNb 中发现了含氧化合物构成的纳米短程序结构，改变了位错剪切模式，丰富了位错滑移体系，增强了强度和延展性。Ding 等 [38] [41][42] 。这种浓度波动或者类似的原子分布不均匀的现象，将减小按照均匀分布计算的混合...…”

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