碳化硼复合材料

MetalmatrixcompositesreinforcedbyB4Cboroncarbide-basedcomposites,Part1,MechanicalpropertiesandwearbehaviorofAl2wt.%CualloycompositesreinforcedbyB4Cnanoparticles,Fig.1.1.MorphologyoftheAlpowder.,Fig.1.2.TEMimageofthenanometerscaledB4Cparticles.,Fig.1.3.Morphologyofthepowdersafter20hofmilling:(a)Al(b)Al2wt.%B4Cand(c)Al4wt.%B4C.,Fig.1.4.SEMmicrographsoftheextrudedcomposites.(a)Al2wt%B4Cand(b)Al4wt%B4C.,Fig.1.5.CrystallitesizeofAlmatrixasafunctionofB4Ccontent,Fig.1.7.Uniaxialtensilestressstrainbehaviorofthesamplespreparedbymechanicalalloyingandhotextrusion.,Fig.1.6.Microhardnessofhotextrudedsamples.,Fig.1.8.Fracturesurfacesofthesamplesafterthetensiletest:(a)coarsegrainedAl(b)nanostructuredAl(c)Al2wt.%B4Cand(d)Al4wt.%B4C.,Fig.1.9.(a)ComparisonofwearrateofcoarsegrainedAl,nanostructuredAlandAlB4Cnanocompositesand(b)variationofwearrateasafunctionofnormalload.,Fig.1.11.SEMmicrographsofthenanostructuredAlunderanormalloadof50N:(a)wornsurfaceand(b)weardebrismorphologies.,Fig.1.10.SEMmicrographsofcoarsegrainedAlunderanormalloadof50N(a)wornsurfacesand(b)weardebrismorphology,Fig.1.12.SEMmicrographsofAl2wt.%B4C.(a)Wornsurfaceand(b)weardebrismorphologiesandAl4wt.%B4Cunderanormalloadof50N.(c)Wornsurfaceand(d)weardebrismorphologies.,Fig.1.13.Opticallongitudinalcross-sectionalmicrographsof(a)coarsegrainedAl,(b)nanostructuredAland(c)Al2wt.%B4Cnanocompositespecimens.,Part2,Thermo-physicalpropertiesofboroncarbidereinforcedcoppercomposites,Fig.2.1.XRDspectrumofasreceivedB4C.B4Cdenotesthepeakscorrespondingtoboroncarbidewithvaryingstoichiometry.,CommerciallyavailableB4C,B4Csurfacecleaning,B4Cacid-treatment,B4Cultrasoniccleaninginalcohol,activationinsalt-basedcolloidpalladium,Fig.2.2.XRDspectrumofthepretreatedB4Cpowders.B4Cdenotesthepeakscorrespondingtoboroncarbidewithvaryingstoichiometry.,Fig.2.3.SEMmicrographsofasreceivedB4C(a)andtheB4Cpowderspretreated(b).,CommerciallyavailableB4C,B4Csurfacecleaning,B4Cacid-treatment,B4Cultrasoniccleaninginalcohol,activationinsalt-basedcolloidpalladium,ElectrolessB4C/Cudeposition,Fig.2.4.XRDspectrumoftheB4Cpowderscoatedcopper(a)andB4Cpowderscoatedcopperaftertheprocessofhydrogenreduction(b).,CommerciallyavailableB4C,B4Csurfacecleaning,B4Cacid-treatment,B4Cultrasoniccleaninginalcohol,activationinsalt-basedcolloidpalladium,ElectrolessB4C/Cudeposition,Hydrogenreductiondeoxidizethecoppers,Fig.2.4.XRDspectrumoftheB4Cpowderscoatedcopper(a)andB4Cpowderscoatedcopperaftertheprocessofhydrogenreduction(b).,Fig.2.5.SEMmicrographsofCucoatingonasreceivedwashedB4Csamples,CommerciallyavailableB4C,B4Csurfacecleaning,B4Cacid-treatment,B4Cultrasoniccleaninginalcohol,activationinsalt-basedcolloidpalladium,ElectrolessB4C/Cudeposition,Hydrogenreductiondeoxidizethecoppers,SPSofcompositepowder,B4C/Cucomposites,Fig.2.6.SEMmicrographsofB4C/Cucompositessintered.,Fig.2.7.XRDspectrumofB4C/Cucompositessintered.,Fig.2.8.TemperaturedependenceofthermalconductivityofB4C/CucompositesandB4Ccermets.,Fig.2.9.Temperaturedependenceofcoefficientofthermalexpansi