SHS／HP合成的TiC-Ni／Mo／W体系耐热梯度夹层特性分析

Heat-Resistant Gradient Material of TiC-Mo/W System Synthesized in SHS/HP Method

摘要:

用自蔓延燃烧合成（SHS）结合水静压（HP）方法（简称SHS／HP法）合成大尺寸TiC-Ni／Mo／W体系耐热对称夹层梯度材料（梯度夹层），对合成产物进行X射线衍射（XRD）、扫描电镜（SEM）和透射电镜（TEM）等分析研究。XRD分析表明反应产物中只有TiC和Ni/Mo/W两相：TEM分析发现面板TiC陶瓷颗粒已经变成椭球状，尺寸细小且组织较均匀，其间为Ni／Mo／W芯子金属相；SEM形貌表明多金属相形貌为小岛状，成连续梯度云状分布。在适当的压力、温度环境下合成致密度、弯曲强度、断裂韧性、硬度值可满足实际应用背景的梯度夹层。在SHS／HP过程中，芯子层中Ni／Mo／W沿试样梯度方向向两层TiC中对称梯度分布。研究判断，夹层特性可能沿梯度方向、垂直梯度方向分别是各向异性和横观各向同性。

Abstract:

Such experimental researches as XRD, SEM and TEM were conducted on the synthesized ceramic heat-resistant gradient material of TiC-Mo/W system prepared by combining SHS with the new method of HP. The result of XRD shows that the reaction product is no other than TiC and Mo/W. TEM analysis finds that TiC ceramic particle becomes a ellipsoidal distribution, tiny and relatively even particle, with Mo/W metal phase in-between; SEM indicates that the shape of multi-metal phase appears to be island-like and distributes in continuous gradient clouds. The compacting density, bending strength, fracture toughness and rigidity value of the synthesis can be prepared to be applicable gradient material structure under suitable pressure and temperature. In the course of SHS/HP, Mo/W distributes into ceramics TiC in the manner of gradient clouds along the sample grade direction. According to the research, the characteristics of the material is anisotropic and transversally isotropic along the direction and vertical grade direction respectively.