High-entropy carbide-nitrides with enhanced toughness and sinterability  

具有高断裂韧性和易烧结性的高熵碳氮化物陶瓷

作　　者：Pan Zhang Xiongjun Liu Anhui Cai Qing Du Xiaoyuan Yuan Hui Wang Yuan Wu Suihe Jiang Zhaoping Lu 张盼;刘雄军;蔡安辉;杜清;袁小圆;王辉;吴渊;蒋虽合;吕昭平(State Key Laboratory for Advanced Metals and Materials,University of Science and Technology Beijing,Beijing 100083,China;State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China;College of Mechanical Engineering,Hunan Institute of Science and Technology,Yueyang 414000,China)

机构地区：[1]State Key Laboratory for Advanced Metals and Materials,University of Science and Technology Beijing,Beijing 100083,China [2]State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China [3]College of Mechanical Engineering,Hunan Institute of Science and Technology,Yueyang 414000,China

出　　处：《Science China Materials》2021年第8期2037-2044,共8页中国科学（材料科学（英文版）

基　　金：supported by the National Natural Science Foundation of China (51671021,51961160729,1179029,51871016 and 51971017);the Funds for Creative Research Groups of China (51921001);111 Project (B07003);the Program for Changjiang Scholars and Innovative Research Team in University of China (IRT14R05);the Project of SKLAMM-USTB (2019Z-01);the Project supported by the State Key Laboratory of Powder Metallurgy,Central South University,Changsha,China。

摘　　要：High-entropy ceramics (HECs) have attracted much attention due to their huge composition space,unique microstructure,and desirable properties.In contrast to previous studies,which have primarily focused on HECs with one anion,herein,we report a new family of ceramics with both multi-cationic and-anionic structures,i.e.,high-entropy carbide-nitrides (Ti0.33Zr0.33Hf0.33)(C0.5N0.5),(Ti0.25Zr0.25Hf0.25-Nb0.25)(C0.5N0.5) and (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)(C0.5N0.5).These as-synthesized HECs are mainly comprised of a face-centered cubic solid-solution phase accompanied by minor inevitable oxide phases.The formation mechanism of the solid-solution phase is discussed in terms of the lattice size difference and thermodynamic competition between configurational entropy and mixing enthalpy.It is found that the increment in the configurational entropy can effectively lower the sintering temperature and increase the fracture toughness.Particularly,the newly developed (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)(C0.5N0.5) exhibits a decent fracture toughness of 8.4 MPa m1/2and a low sintering temperature of 1750°C,making it promising for ultra-high temperature applications.Our work not only enriches knowledge regarding the HECs categories,but also opens a new pathway for developing HECs with multi-cationic and-anionic structures.高熵陶瓷由于具有巨大的成分空间、独特的微观结构和良好的性能而倍受关注.与现有高熵陶瓷研究主要集中在以单个阴离子和多个阳离子组成的混合结构不同,本文报道了一系列具有多阴离子和多阳离子混合而成的新型高熵陶瓷:(Ti0.33Zr0.33Hf0.33)-(C0.5N0.5),(Ti0.25Zr0.25Hf0.25Nb0.25)(C0.5N0.5)和(Ti0.2Zr0.2Hf0.2Nb0.2-Ta0.2)(C0.5N0.5).这类高熵陶瓷主要由面心立方固溶体相组成,同时伴随着少量不可避免的氧化物相.从晶格尺寸差、构型熵和混合焓的竞争关系对其形成机制进行了分析讨论.由于多阴离子带来的高熵效应,新开发的高熵陶瓷材料具有良好的断裂韧性和易烧结性.特别是,(Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)(C0.5N0.5)的断裂韧性高达8.4 MPa m1/2,具有作为超高温防护材料的应用前景.该工作不仅丰富了高熵陶瓷的种类,而且为开发具有多阴离子和阳离子结构的高熵陶瓷提供了新的思路.

关 键 词：high-entropy ceramics multi-cationic and-anionic structure high-entropy effect fracture toughness sintering temperature 

分 类 号：TQ174.758.12[化学工程—陶瓷工业]