SiC(w)/TZP+mullite陶瓷复合材料界面和组成设计与力学性能

Interfacial and Compositional Design and Mechanical Properties of SiC(w)/TZP+mullite(p) Composites

本文从理论上分析了 SiC(w)/TZP+mullite(p)复合材料界面残余热应力及其在基质内的分布规律.提出在SiC(w)表面涂复 Al_2O_3和在 PZT 中加入 mullite(p)联合作用来降低晶须/基质界面残余热应力的界面设计方案,导出 SiC(w)和 mullite(p)协同补强 PZT 的匹配条件.制备了 SiC(w)/TZP+mullite(p)复合材料并研究了 SiC(w)表面涂层 Al_2O_3厚度和 SiC(w)加入量对复合材料室温和高温力学性能的影响.SEM 断口观察表明 SiC(w)表面涂层 Al_2O_3和在 PZT 中加入 mullite(p)提高了晶须拨出效应.经 SiC(w)和 mullite(p)体积分数及直径的匹配优化,复合材料1000℃抗弯强度达470MPa,实现了协同高温补强.

Interfacial residual thermal stress and its distribution in the matrix were theoreticallyanalyzed for SiC(w)/TZP+mullite(p)composites.The idea of reducing residual thermal stressof the interface between SiC(w)and TZP by coating Al_2O_3 on SiC(w)and by adding mullite(p)in TZP was suggested.The critical coordinative conditions of whiskers and particulates werededuced for the synergistic reinforcement of TZP.The composites of SiC(w)/TZP+mullite(p)were prepared.The effects of Al_2O_3 coating thickness on the surface of SiC(w)and the addedvolume fraction of SiC(w)on the mechanical properties of the composites at room temperatureand 1000℃ were studied.The SiC(w)pull out phenomena were observed with SEM on thefracture surface of the composites.After the coordinative adjustment in volume fractions and inratio of diameters of SiC(w)and mullite(p),the maximal bending strength 470 MPa at 1000℃was obtained and the synergistic reinforcement via the whiskers and particulates was achieved.