原位合成(TiB_2+TiC)/Ti_3SiC_2复相材料及其性能研究  

In-situ Synthesis and Mechanical Properties of (TiB_2+TiC)/Ti_3SiC_2 Composites

作　　者：顾巍[1] 杨建[1] 丘泰[1] 祝社民[1] 

机构地区：[1]南京工业大学材料科学与工程学院,南京210009

出　　处：《无机材料学报》2010年第10期1081-1086,共6页Journal of Inorganic Materials

基　　金：国家高技术研究发展863计划(2009AA05Z313);江苏省高校自然科学基础研究项目(07KJB430039)~~

摘　　要：在热力学分析的基础上,以TiH2粉、Si粉、石墨粉与B4C粉为原料,采用热压烧结法原位合成制备了(TiB2+TiC)/Ti3SiC2复相材料.采用X射线衍射、扫描电镜与透射电镜对材料的物相组成和显微结构进行了表征,研究了烧结温度对材料物相组成、烧结性能、力学性能与显微结构的影响.结果表明,1400～1600℃烧结温度范围内均能获得致密的(TiB2+TiC)/Ti3SiC2复合材料.随着烧结温度的升高,复合材料的强度、断裂韧性与显微硬度均逐渐提高,1500～1600℃烧结所得复合材料具有优化、微细的显微结构,抗弯强度与断裂韧性均分别高于700MPa与9MPa·m1/2,显微硬度为7.33～8.31GPa.原位合成的柱状TiB2与等轴状TiC协同作用,通过颗粒增强、裂纹偏转、晶粒拔出、晶粒细化等机制对Ti3SiC2基体起到了显著的补强增韧效果.Based on thermodynamic analysis,（TiB2＋TiC）/Ti3SiC2 composite ceramics were in-situ prepared by hot-pressing with TiH2,Si,graphite and B4C powders as raw materials.The phase composition and microstructure of the materials were characterized by XRD,SEM and TEM.Effects of sintering temperature on phase composition,sintering performance,microstructure and mechanical properties were investigated.The results indicate that fully densified（TiB2＋TiC）/Ti3SiC2 composite ceramics could be obtained after sintered at 1400-1600℃.With the increase of sintering temperature,the bending strength,fracture toughness and Vickers hardness of the composite increase gradually.The materials sintered at 1500-1600℃ show optimized microstructure and consequently excellent mechanical properties,i.e.,bending strength of above 700MPa,fracture toughness of above 9MPa·m1/2 and Vickers hardness of 7.33-8.31GPa.As reinforcing agents,columnar TiB2 grains and equiaxed TiC grains,were incorporated by in-situ reaction during hot-pressing process to increase the strength and toughness of Ti3SiC2 matrix dramatically by the synergistic action of the mechanisms such as particulate reinforcement,crack deflection,grain＇s pull-out and fine-grain toughening.

关 键 词：(TiB2+TiC)/Ti3SiC2 原位合成 热压烧结 力学性能 增韧机理 

分 类 号：TB332[一般工业技术—材料科学与工程]