[1]罗颐秀,王京阳.稀土双硅酸盐热学性能的基因与协同调控机制[J].中国材料进展,2019,(09):866-874.[doi:10.7502/j.issn.1674-3962.201906043]
Luo Yixiu,Wang Jingyang.Thermal Properties of RareEarth Disilicates:Material Genome and Coordinated Mechanism[J].MATERIALS CHINA,2019,(09):866-874.[doi:10.7502/j.issn.1674-3962.201906043]
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稀土双硅酸盐热学性能的基因与协同调控机制(
)
中国材料进展[ISSN:1674-3962/CN:61-1473/TG]
- 卷:
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- 期数:
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2019年第09期
- 页码:
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866-874
- 栏目:
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前沿综述
- 出版日期:
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2019-09-30
文章信息/Info
- Title:
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Thermal Properties of RareEarth Disilicates:Material Genome and Coordinated Mechanism
- 作者:
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罗颐秀; 王京阳
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（中国科学院金属研究所，辽宁，沈阳，110016）
- Author(s):
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Luo Yixiu; Wang Jingyang
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(Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China)
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- 关键词:
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稀土双硅酸盐; 多功能热障/环境障一体化涂层; 热导率; 热膨胀; 声子非简谐性
- Keywords:
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Rare-earth disilicate; Multifunctional thermal and environmental barrier coating (TEBC); Thermal conductivity; Thermal expansion; Phonon anharmonicity
- 分类号:
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V25
- DOI:
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10.7502/j.issn.1674-3962.201906043
- 文献标志码:
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A
- 摘要:
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在未来航空发动机先进技术中，以硅基陶瓷复合材料高温结构部件为基体，发展先进的多功能热障/环境障一体化涂层（TEBC）以实现有效防护是一个重要的研究方向。TEBC材料的发展和优化需满足低热导率（κL）和合适的热膨胀系数（CTE），以提高涂层体系的隔热性-RE2Si2O7（RE=Y, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu）多晶型材料的晶体结构、键合非均匀性、声子色散关系及非简谐性特征，计算了材料本征晶格热导率和热膨胀系数，揭示了控制材料低热导率和热膨胀系数大小的“基因”。研究发现，RE2Si2O7多晶型材料具有明显的低频光学-声学声子耦合效应，且低频声子较大的非简谐性是材料低热导率的根源。同时，晶格中Si—O—Si“桥”结构的线性或弯折形态导致了低频声子非简谐性的“正负”差异及体模量差异，是决定β-和γ-RE2Si2O7热膨胀系数远低于δRE2Si2O7的关键因素。研究结果阐明了低频声子非简谐性的“大小”和“正负”特征对RE2Si2O7多晶型材料热学性能协调机制的关键作用，为实现TEBC热学性能的优化设计提供了指导。
- Abstract:
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In the future of aeroengine technology, silicon based ceramic matrix composite (CMC) has important applications as structural materials for the hotsection components, which, in the combustion environment, needs to be protected by multifunctional thermal and environmental barrier coating (TEBC). The threshold requirements for the design of advanced TEBC system include low thermal conductivity, which protects the CMC substrates from thermal attack; and compatible thermal expansions with substrates, in order to minimize the thermal stress during thermal cycling. Therefore, a comprehensive understanding of the coordinated mechanism of thermal conduction and thermal expansion for candidate materials, from the perspective of “material genome”, is a key challenge. In this paper, the structural characteristics, heterogeneity of interatomic bonding, phonon dispersions and phonon anharmonicity for rareearth disilicates (β-, γ- and δ-RE2Si2O7, RE=Y, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) are studied based on firstprinciples calculations combined with lattice dynamics. Intrinsic lattice thermal conductivity (κL) and coefficient of thermal expansion (CTE) are calculated, and the “gene” that controls the thermal properties of RE2Si2O7 polymorphs are discussed. It is found that lowfrequency optical phonons are obviously coupled with acoustic phonons, and the high anharmonicity for lowfrequency phonons is the origin of low κL for β, γ- and δ-RE2Si2O7. Besides, the “gene” that controls the thermal expansions of RE2Si2O7 polymorphs are found to be the linear or bent configuration of Si—O—Si “bridge”, which determines the positive or negative anharmonicity for lowfrequency phonons, as well as the bulk modulus, and finally lead to obviously lower CTE for β- and γ-RE2Si2O7 as compared with δ-RE2Si2O7. These results highlight that, the anharmonicity for low-frequency phonons, i.e. the “magnitude” and the “positive or negative” values, is the key for coordinated tuning of κL and CTE for RE2Si2O7. These understandings bring new inspirations for the design and optimization of TEBC systems.
备注/Memo
- 备注/Memo:
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收稿日期：2019-06-29修回日期：2019-08-07 基金项目：国家科技重大专项项目（2017-VI-0020-0093)；国家自然科学基金资助项目（51772302）第一作者：罗颐秀，女，1990年生，博士研究生通讯作者：王京阳，男，1971年生，研究员，博士生导师，Email: jywang@imr.ac.cn
更新日期/Last Update:
2019-08-30