中文摘要：

以Ti、B_4C和SiC晶须（SiC_w）为原料,采用自蔓延高温合成法制备了多孔TiB__2-TiC复合材料。讨论了SiC_w含量对TiB__2-TiC复合材料物相、组织形貌、孔隙率和抗压强度的影响。结果表明：不添加SiC_w时,复合材料中主要物相为贫硼相TiB和Ti_3B_4以及TiC和少量TiB__2;在5Ti＋B_4C体系中加入SiC_w后,贫硼相TiB和Ti_3B_4逐渐减少直至消失,而出现富硼相TiB__2和TiC的含量增加。随着SiC_w含量的增加,复合材料的孔隙率逐渐增加,由38.46%增加至5_2.78%。当SiC_w含量小于1.0时,随着SiC_w含量的增加,多孔TiB_2-TiC复合材料的抗压强度明显增加,当SiC_w含量为1.0时,复合材料的抗压强度达到最大值56.04MPa。Ti与SiC_w反应会生成TiC、Ti_3SiC_2和TiSi_2等物相,消耗一定量的Ti,使得与B4C反应的Ti量减少,从而促进富硼相TiB_2形成和TiC的增多。并且在SiC_w表面形成颗粒状TiC或者层片状Ti_3SiC_2,增加SiC_w与TiB_2-TiC基体之间的结合,更有利于发挥SiC_w的强化作用。

英文摘要：

Porous TiB_2-TiC composites were produced by self-propagating high-temperature synthesis method,with Ti,B4 C and SiC whiskers（SiC_w ）as raw materials.The effects of SiC_w content on phases,microstructures,porosity and compressive strength of TiB_2-TiC composites were studied.The results show that the composites are mainly composed of poor boron phases TiB and Ti_3B_4,TiC and a little TiB_2 when there is no SiC_w added.After adding SiC_w into 5Ti＋B4C system,the poor boron phases TiB and Ti_3B_4 decrease and even disappear,while the content of rich boron phase TiB_2 and TiC increase.With the increasing of SiC_w content,the porosity of composites gradually increases from 38.46%to 52.78%.When the content of SiC_w is less than 1.0,the compressive strength of porous TiB_2-TiC composites improves significantly with the increasing of SiC_w content and reaches to the maximum value of 56.04 MPa when the content of SiC_w is 1.0.A part of Ti is consumed by reacting with SiC_w to form TiC,Ti_3SiC_2 and TiSi2phases,so less Ti is remaining to react with B4 C.This promotes the formation of rich boron phase TiB_2 and TiC.Moreover some of the granular TiC or lamellar Ti_3SiC_2 grow around the surface of SiC_w ,which is beneficial to improve the bonding strength of SiC_w and TiB_2-TiC matrix,and the effect of SiC_w reinforcement.