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1、第8卷第4期材料与冶金学报Vol18No142009年12月JournalofMaterialsandMetallurgyDec12009包覆工艺制备C-SiC-B4C-TiB2复合材料的组织与性能喻亮,茹红强,左良,薛向欣(东北大学材料各向异性与织构教育部重点实验室,沈阳110004)摘要:以鳞片石墨,B4C,SiC,TiO2为原料,利用包覆工艺在不同热压温度下制备了w(C)=50%的C-SiC-B4C-TiB2复合材料,并详细研究了热压温度对复合材料显微组织和性能的影响规律.结果表明,当热压温
2、度高于1850℃时,复合材料由C,SiC,B4C和TiB2这四相组成;复合材料的体积密度、抗折强度和断裂韧性均随着热压温度的升高而增加.2000℃热压时,复合材料的体积密度、气孔率、抗折强度和断31/2裂韧性分别达到2141g/cm,3142%,176MPa和611MPa·m;热压温度升高,复合材料的碳相和陶瓷相逐渐致密,碳相最终形成了在陶瓷基体上镶嵌的直径为40μm橄榄球状和条状这两种形貌.碳/陶瓷相的弱界面分层诱导韧化和第二相TiB2与陶瓷基体之间热膨胀系数不匹配所致的残余应力使变形过程中微裂
3、纹的扩展路径发展变化,使复合材料的韧性提高1关键词:C-SiC-B4C;C鳞片;包覆工艺;显微组织;力学性能中图分类号:TB335文献标识码:A文章编号:167126620(2009)0420272204MicrostructureandpropertiesofC-SiC-B4CcompositespreparedbycoatingprocessingYULiang,RUHong2qiang,ZUOLiang,XUEXiang2xin(KeyLaboratoryforAnisotropyandTe
4、xtureofMaterials(MinistryofEducation),NortheasternUniversity,Shenyang110004,China.)Abstract:C-SiC-B4Ccarbon/ceramiccompositeswith50%(massfraction)contentofgraphiteflakewerepreparedfromgraphiteflake,B4C,SiCandTiO2bythecoatingandhot-pressingtechnologyat
5、differenttemperatures.TheeffectsofsinteringtemperatureonthemicrostructuresandpropertiesofC-SiC-B4Ccompositeswerestudied.ResultsshowthatC,SiC,B4CandTiB2existinthecompositewhenthetemperatureishigherthan1850℃.Thebulkdensity,flexuralstrengthandfracturetou
6、ghnessofthecompositesincreasewithhot-pressing3temperatureincreasing.Thebulkdensity,apparentporosity,flexuralstrengthandfracturetoughnessare2141g/cm,1/23142%,176MPaand611MPa·mrespectivelyat2000℃.Duringtheprocessofsintering,twokindsofmorphologyofthecarb
7、onphasehavebeenfound,olivaryshapedwithdiameter40μmandstriatedstructure.Carbon-ceramicweakboundaryconditionstratifycausedbythemicro-crackandthechangesinthemicro-crackpropagationrouteduetotheexistencetheresidualstressbythemismatchoftheheatexpansioncoeff
8、icientsbetweenthesecondphaseTiB2andceramicmatrixenhancedthetougheningofthecomposites.Keywords:C-SiC-B4C;graphiteflake;coatingprocessing;microstructure;mechanicalproperty[8～9][10]C-SiC-B4C复合材料可将炭素的耐热、导启忠等,颜冲等比较了石油焦和鳞片石墨电、润滑和耐腐蚀性等优点和陶瓷的机械强度高、分别作
