摘要
超高温陶瓷(UHTC)Ta_(4)HfC_(5)因其优异的热物理和热机械性能而成为适用于高超音速飞行器最有前途的候选材料之一.然而,较差的烧结能力限制了其潜在的使用.为了克服该障碍,采用Si_(2)BC_(3)N陶瓷对钽-铪碳化物固溶体进行了致密化处理.通过热压烧结合成了致密的Ta_(4)HfC_(5)-Si_(2)BC_(3)N陶瓷,所得复相陶瓷由Ta_(4)HfC_(5),SiC和BN(C)相组成.在2100℃下,随着晶粒的快速生长,陶瓷内形成了“蝌蚪”状的SiC和BN(C)连接相,断裂韧性提高到3.47±0.12 MPa m^(1/2).随着烧结温度的升高,Ta_(4)HfC_(5)晶粒的生长活化能从112.4 kJ mol^(−1)增加到250.7±29.3 kJ mol^(−1).
The ultrahigh-temperature ceramic(UHTC)Ta_(4)HfC_(5) is one of the most promising candidate materials suitable for the use in hypersonic aircrafts because of its ex-cellent thermophysical and thermomechanical performance.However,the poor sintering ability is one of the main reasons restricting its potential application.To overcome this obstacle,Si_(2)BC_(3)N ceramic was used to densify the tantalum hafnium carbide solid solution.Thus,dense Ta_(4)HfC_(5)-Si_(2)BC_(3)N ceramics were synthesized by hot-pressing sintering.The resulting composite ceramic was comprised of crystalline Ta_(4)HfC_(5),SiC and BN(C)phases.A“tadpole-like”shape of SiC and BN(C)connecting phase was formed accompanied by rapid grain growth at 2100℃,increasing the fracture toughness to 3.47±0.12 MPa m^(1/2).The growth mechanism of the Ta_(4)HfC_(5) grains gradually changed from grain-boundary sliding by volume diffusion to grain boundary diffusion,attributed to the grain growth activation energy changing from 112.4 to 250.7±29.3 kJ mol^(−1) with increasing sintering temperature.
作者
关景怡
李达鑫
周国相
段文久
杨治华
贾德昌
Ralf Riedel
秦少华
周玉
Jingyi Guan;Daxin Li;Guoxiang Zhou;Wenjiu Duan;Zhihua Yang;Dechang Jia;Ralf Riedel;Shaohua Qin;Yu Zhou(Institute for Advanced Ceramics,School of Materials Science and Engineering,Harbin Institute of Technology,Harbin 150000,China;Key Laboratory of Advanced Structural-Functional Integration Materials&Green Manufacturing Technology,Harbin Institute of Technology,Harbin 150001,China;Chongqing Research Institute of HIT,Chongqing 401135,China;Tsinghua Shenzhen International Graduate School,Tsinghua University,Shenzhen 518055,China;Institut für Materialwissenschaft,Technische Universität Darmstadt,Darmstadt D-64287,Germany;School of Materials Science and Engineering,Harbin Institute of Technology,Harbin 150001,China)
基金
financially supported by the National Natural Science Foundation of China(52002092,52172068,52232004)
Heilongjiang Natural Science Fund for Young Scholars(YQ2021E017)
Heilongjiang Touyan Team Program and Advanced Talents Scientific Research Foundation of Shenzhen
the financial support provided by the Research Training Group GRK 2561“Mat ComCom Mat:Materials Compounds from Composite Materials for Applications in Extreme Conditions”funded by the Deutsche Forschungsgemeinschaft(DFG),Bonn,Germany。
