简介：Thisstudyanalyzestheevolutionofcarbidesinthetemperingprocessofanewlydevelopedsemi-highspeedsteelcoldforgedrollwithnitrogenadditionusingatransmissionelectronmicroscope(TEM)equippedwithanenergydispersiveX-ray(EDX).TheprecipitationsequenceofthecarbideswasidentifiedintheentiretemperingprocessanditcanbeexpressedasM3C→M3C+M(C,N)Ⅱ→M(C,N)Ⅱ+M7C3Ⅱ+M23C6.ThesecondaryhardeninginthetemperingprocesswasmainlyduetothedispersedprecipitationoffineM(C,N)Ⅱparticles.ThedissolutionofM3CtemperedathightemperaturesinducedtheprecipitationandcoarseningofM7C3ⅡandM23C6.

简介：Semi-solidAl2Y/AZ91magnesiummatrixcompositesslurrywaspreparedbyultrasonicvibration,effectofultrasonicvibrationtemperatureandtimeonmicrostructureofsemi-solidslurrywasinvestigated.Theresultsshowedthatwiththeultrasonicvibrationtemperaturedecreasingthesolidvolumefractionofsemi-solidslurryincreased.Thebestultrasonicvibrationtemperaturewas600oC.Withtheincreaseofultrasonicvibrationtime,theaveragegraindiameterofprimaryа-Mgparticlesdecreasedfirstly,thenincreased,theaverageshapefactorincreasedgraduallyanddecreasedslightlyafter90s,andafewrosettedendriteswereobservedafter120s.Thebestsemi-solidslurrywithaveragegraindiameterof75μmandshapefactorof0.7weregainedafterthemeltwastreatedbyultrasonicvibrationforabout60satnearliquidustemperature(600oC).Atlast,themicrostructureevolutionmechanismofsemi-solidmagnesiummatrixcompositesslurrywasanalyzedbythetheoriesofthermodynamicsandkinetics.