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1、第29卷第3期硅酸盐学报Vol.29,No.32001年6月JOURNALOFTHECHINESECERAMICSOCIETYJune,2001SiC基层状复合材料界面层的选择121122袁广江,罗永明,陈大明,周洋,欧阳俊,潘伟(1.北京航空材料研究院先进复合材料国防科技重点实验室,北京100095;2.清华大学材料科学与工程系,北京100084)摘要:利用凝胶注模成型SiC基体层,以喷涂法、流延法、金属箔法、浸涂法分别加涂W,W-2%(质量分数,下同)Co,Ta,BN界面层,通过热压烧结制备了SiC/W,SiC/W-2%Co,SiC/Ta,SiC/BN层状复合材料.在
2、复合材料高温制备过程中,金属W,W-2%Co,Ta与SiC反应生成了碳化物和硅化物,失去了金属塑性,未能实现裂纹尾流区桥接、残余应力增韧等金属界面层层状复合材料赖以大幅度提高其强韧性的增韧机制,其增韧效果仅与BN陶瓷界面层的增韧效果相当.此外,研究表明,提高基体层力学性能可以显著提高层状复合材料的强韧性.制备的SiC/BN层状复合材料的室温三点弯曲强度为729.86114.02MPa、室温断裂韧性为20.582.77MPam1/2,其主要增韧机制包括裂纹分叉钝化、裂纹偏转、裂纹并行扩展以及裂纹尾流区片层拔出等.关键词:层状复合材料;界面层;金属;氮化硼;碳化硅中图分类号:TQ17
3、4.1;TQ174.758.2文献标识码:A文章编号:0454-5648(2001)03-0226-06SELECTIONOFINTERFACIALLAYEROFLAMINATEDSILICONCARBIDEMATRIXCOMPOSITES121122YuanGuangjiang,LuoYongming,ChenDaming,ZhouYang,OuyangJun,PanWei(1.NationalKeyLaboratoryofAdvancedComposites,BeijingInstituteofAeronauticalMaterials,Beijing100095;2.M
4、aterialScienceandEngineeringDepartment,TsinghuaUniversity,Beijing100084)Abstract:SiC/W,SiC/W-2%Co,SiC/Ta,SiC/BNlaminatedcompositesinwhichSiCmatrixlayerswerepreparedbygelcastingwerefabricatedbyhotpressingtechnique.W,W-2%Co,TaandBNlayerswhichwerepreparedbyspraying,doctorblading,gelcasting,etc.res
5、pectively,as_receivedfoilandcoatingwereusedasinterfacialmaterialsoflaminatedSiCmatrixcomposites.Athightemperaturethatwasneededforthepreparation,W,TareactedwithSiCtoformcarbideandsilicide,whichhadlittleplasticityandunabletoachievethetoughnessimprovementoflaminatedcompositesbymetalbridgingandresid
6、ualstrain.However,itisfoundthatthetoughnessandstrengthofthelaminatedcompositesaresignificantlyincreasedbyimprovingthepropertiesofthematrixmaterial.SiC/BNlaminatedcompositeswiththreepointbendingstrengthandnominalfracturetoughnessof729.86114.02MPaand1/220.582.77MPamrespectivelyareobtained.Thema
7、inmechanismofenhancingtoughnessisattributedtocrackbluntness,crackdeflexion,crackparallelpropagationandpull_outofmatrixlayer.Keyword:laminatedcomposites;interfaciallayer;metal;boronnitride;carbonsilicate陶瓷材料是一种本质脆性材料,在制备、机械
