简介:Microstructureofthematrixdirectlyinfluencestheperformanceandtheapplicationofmetalmatrixcomposites.Byusingvacuumcasting-infiltrationmethodtomanufacturecastingtungstencarbideparticlereinforcedcomposite,theadditionofNicanalterthemicrostructureofthematrixofcomposite.Highcarbonchromiumsteelwaschosenasthesubstrate.Thecastingprocesswasachievedat1580℃withvacuumdegreeof0.072—0.078MPa.Paddingofthemoltensteelineachpartofthepreformwasdifferent,andthesolidificationofeachpartofthecompositewasdifferent,too.Microstructureofthematrixwasvariousindifferentpartsofthecomposite.TheNiadditionhadenlargedtheaustenitezoneinmatrix,whichwouldimprovethecorrosionresistanceofthecomposite.ThephaseidentificationofthecompositewasperformedbyX-raydiffractiontechnique.TheresultshowedthatFe3W3Cwastheprimaryprecipitatedcarbideanditscompositionhadadirectlinkwiththedecompositionofthecastingtungstencarbideparticles.Thehardnessofthematrixmainlydependedonthereinforcedcarbide,i.e.Fe3W3C.
简介:TheagingbehaviorsofirradiatedtungstenbyhighenergySi3+andH+ionsaremainlyinvestigatedusinginternalfriction(IF)methodcombinedwithSEMtechnology.TheSEManalysisindicatesthatmoresevereirradiationdamageappearsinthesurfaceofsimultaneousdualSi3+H+irradiatedspecimenthanthatinthesequentialdualSi3+H+irradiatedspecimenorthesingleSi3+irradiatedspecimensbecauseofthesynergisticeffectofSiandHirradiation.TheIFbackgroundoftheirradiatedsampleisaboutoneorderofmagnitudehigherthanthatoftheunirradiatedsampleowingtotheexistenceofhighdensityfreshdislocationsinducedbySi/Hirradiation,InthesequentialdualSi3+andH+irradiatedspecimen,thehydrogenSnoek-Ke-Koster(SKK)peakassociatedwiththemovementofdislocationsdragginghydrogenatomsisobservedanditsheightdecreaseswithagingtimeatroomtemperature.AsforthesimultaneousdualSi3+H+irradiatedspecimen,however,thereisnosuchhydrogenSKKpeak.Thereasoncanbeexplainedashydrogendiffusionandpinningeffectofdislocations.