在碳化物陶瓷中构筑金属原子层分相共生结构  

Establishment of Symbiotic Structure with Metal Atomic-layer Phase-separation in Carbide Ceramics

作　　者：鲍伟超 郭晓杰 辛晓婷 彭湃 王新刚[1] 刘吉轩 张国军 许钫钫[1] BAO Weichao;GUO Xiaojie;XIN Xiaoting;PENG Pai;WANG Xingang;LIU Jixuan;ZHANG Guojun;XU Fangfang(State Key Laboratory of High Performance Ceramics and Superfine Microstructure,Shanghai Institute of Ceramics,Chinese Academy of Sciences,Shanghai 200050,China;State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,Institute of Functional Materials,Donghua University,Shanghai 201620,China;Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院上海硅酸盐研究所,高性能陶瓷和超微结构国家重点实验室,上海200050 [2]东华大学功能材料研究中心,纤维材料改性国家重点实验室,上海201620 [3]中国科学院大学材料科学与光电子功能中心,北京100049

出　　处：《无机材料学报》2025年第1期17-22,共6页Journal of Inorganic Materials

基　　金：国家自然科学基金(52032001,52102081);上海市无机非金属材料分析测试表征专业技术服务平台(19DZ2290700)。

摘　　要：在保持结构陶瓷高硬度的同时提高其韧性和塑性,可以显著拓展其在极端环境中的应用前景,其中微结构设计是一项重要策略。本工作研究了在碳化物陶瓷中构筑金属单原子层分相共生结构的可行性。以过渡金属单质、石墨和少量Al为原材料,采用放电等离子体烧结工艺在1900℃和30 MPa压力下制备不同组元数的过渡金属碳化物陶瓷,发现只有高熵(TiZrHfNbTa)C陶瓷形成了Al原子层分相共生结构。该结构不是长程序的单相化合物(如MAX相),而是一种无周期性的碳化物和金属单原子层交叉堆叠的复合物。通过纳米至原子尺度的球差校正透射电子显微镜和能谱表征,揭示了少量Al单原子层无周期性地嵌入高熵碳化物面心立方结构的{111}面。结合第一性原理计算,发现形成原子层分相共生结构的关键因素不是Al在不同碳化物晶格中的扩散差异,而是高熵带来的热力学稳定性、晶格畸变和迟滞扩散效应等。本研究有助于推动结构陶瓷中原子尺度微结构的设计和调控,从而获得硬度-强度-韧性综合力学性能优异的结构陶瓷。Microstructural design is a promising strategy to enhance the toughness and plasticity of structural ceramics while maintaining their inherently excellent hardness,which can facilitate their applications in extreme environments.In this work,the possibility of establishing a symbiotic structure with metal atomic-layer phase-separation(MALPS)in carbide structural ceramics was investigated.The carbide ceramic samples were synthesized from raw materials comprising transition metals with different component numbers,graphite powders,and a small amount of aluminum by spark plasma sintering at 1900℃and under a pressure of 30 MPa.It was found that Al-MALPS structure was observed exclusively in the high-entropy(TiZrHfNbTa)C ceramic,which was not a MAX phase with long-range-order but rather a composite featuring a non-periodic cross-stacking of single metal atomic layers within the carbide matrix.Characterization by spherical aberration correction transmission electron microscopy and energy dispersive spectroscopy from nanometer to atomic scales revealed that the single Al atomic layers were sparsely embedded onto the{111}planes of the carbide face-centered cubic structure.Combined with the first-principles calculations,the formation of MALPS structure was found to be driven by thermodynamic stability,lattice distortion,and sluggish-diffusion effect of high entropy,rather than the differential diffusion of Al in various carbide lattices.This work could promote the design and regulation of atomic-scale microstructures in structural ceramics,aiming for high performance with synergetic high hardness-strength-toughness.

关 键 词：结构陶瓷 高熵碳化物陶瓷 金属原子层分相 共生结构 

分 类 号：TQ174[化学工程—陶瓷工业] P575[化学工程—硅酸盐工业]