碳纳米管增强Nb/Nb5Si3复合材料的制备及强韧化机制研究

项目名称： 碳纳米管增强Nb/Nb5Si3复合材料的制备及强韧化机制研究

项目编号： No.51271091

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 一般工业技术

项目作者： 龙文元

作者单位： 南昌航空大学

项目金额： 80万元

中文摘要： Nb/Nb5Si3复合材料具有高熔点、高刚度、低密度和极高的高温强度等优点，同时其较差的室温韧性和冷加工能力阻碍了它作为高温结构材料的应用。碳纳米管（CNTs）具有超强的力学性能，可以极大改善复合材料的强度和韧性。在前期研究中发现掺杂CNTs对Nb/Nb5Si3复合材料的强度和断裂韧性都有一定的影响。因此，本项拟采用放电等离子烧结技术制备Nb/Nb5Si3复合材料，引入CNTs作为弥散相来提高Nb/Nb5Si3复合材料的强度和断裂韧性；研究CNTs增强Nb/Nb5Si3复合材料的制备、性能、显微结构以及断裂特征的相互关系；分析CNTs增强相的形态、尺寸、分布及不同相之间的界面结构，研究CNTs相与基体界面结合行为与特征；分析复合材料的断面形貌、压痕裂纹扩展情况，探讨CNTs对Nb/Nb5Si3复合材料增韧补强的作用效果与机制，为其在航空、航天和国防等领域高温结构材料中应用奠定基础。

中文关键词： 碳纳米管；放电等离子烧结；强韧化；桥联效应；拔出效应

英文摘要： Nb/Nb5Si3 in situ composite has high melting point, high stiffness, low density and excellent specific mechanical properties at high temperature. However, low fracture toughness at room temperature and poor deformability even at elevated temperature hinder their applications like many other intermetallic compounds. Carbon nanotubes have a very high theory strength, It was reported that the addition of carbon nanotubes could greatly improve the mechanical behaviors of metal-based composites. It is discovered in study at present that the addition of CNTs could improve the strength and fracture toughness of Nb/Nb5Si3 in situ composite. Therefore, the Nb/Nb5Si3 in situ composites will be fabricated by SPS in this project. The relationships between preparation, properties, microstructure and fracture characteristics of CNTs reinforced Nb/Nb5Si3 in situ composites are studied. The interface bonding behavior and characteristics between CNTs and matrix are investigated by analyzing the shape, size and the distribution of CNTs and interfacial structure.Toughening and reinforcing mechanism of CNTs on Nb/Nb5Si3 in situ composites are studied by analyzing fracture morphologies and crack propagation of the composites. The results made a base for thermo-structural material in aviation, aerospace and national defense industry

英文关键词： CNTs；SPS；Strengthening and Toughening；bridging；pullout