简介：Themicrostructureofstress-inducedmartensite(SIM)inthenanocrystallineNiTialloywasinvestigatedbymeansoftransmissionelectronmicroscopy(TEM).Theresultshowsthatthemulti-variantstructureofthemartensiteissuppressedandonlysingle-variantmartensitictwinsformaftertensiledeformationwhenthegrainsizeissmallerthan80nm.Thenormaldirectionsofthe(001)B190twinplanesareallwithintherangeof45°fromtheaxialdirectionofthewire.Theanglebetweentwincrystals(1'11)Mand(111)ToftheSIMisalsofoundtobesmallerthanthatofthermallyinducedmartensiteinnanocrystallineNiTi.

简介：ＥｆｆｅｃｔｏｆＴｗｏ－ｔｉｍｅｓＡｎｎｅａｌｉｎｇｏｎＣｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆＴｉＮｉＳｈａｐｃ－ｍｅｍｏｒｙＡｌｌｏｙＺｈａｎｇＪｉｎｂｏ，ＳｕｎＸｕ，ＷａｎｇＦｕｓｈｅｎｇａｎｄＨｅＹｏｎｇｊｉａｎ（张金波（孙序）（王福生）（何勇健）...

简介：Microstructuresandpropertiesofcapacitordischargewelded(CDW)jointofTiNishapememoryalloy(SMA)andstainlesssteel(SS)werestudied.Thefracturecharacteristicsofthejointwereanalyzedbymeansofscanningelectronmicroscope(SEM).MicrostructuresofthejointwereexaminedbymeansofopticalmicroscopeandSEM.Theresultsshowedthatthetensilestrengthoftheinhomogeneousjoint(TiNi-SSjoint)waslowandthejointwasbrittle.BecauseTiNiSMAandSSmelted,abrittleas-caststructureandcompoundwereformedintheweld.Thetensilestrengthandtheshapememoryeffect(SME)ofTiNi-SSjointwerestronglyinfluencedbythechangesofcompositionandstructureoftheweld.MeasuresshouldbetakentopreventdefectsfromformingandextrudingexcessivemoltenmetalintheweldforimprovingthepropertiesofTiNi-SSjoint.

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简介：Thispaperstudiesmechanicalpropertyandfractographyoftheweldedjointsobtainedindifferentweldingparameterssuchasweldingheatandweldingpresswith/withoutgasshieldinTiNishapememoryalloyprecisepulseresistancebuttweldingusingtensilestrengthtest,XRD,SEMandTEMmeasures.Theoptimumweldingparametersobtaininghightensilestrengthweldedjointaregot.Ontheconditionofweldingpressmagnetingcurrent2Aandweldingheat75%,thejointstrengthisthehighest.ThisisimportantfortostudyotherpropertiesofTiNishapememoryalloyfurther.Theexperimentalresultsstatethatargongasshieldhavedifferenteffectsondifferentweldingparameters,lessonweldingpress,butgreatonweldingheat.Butexcessiveweldingpressandweldingheathavegreateffectsonjointtensilestrength.Toohighweldingheatcanproducethenewintermetalliccompound,thisintermetalliccompoundleadtodislocationdensitytoincreaseandformthepotentialcrackinitiation,whichcaneasilymakethejointfractureunderstresseffectanddecreasetheshapememoryratioofjointforhighdensitydislocationgroupsexistinginthetwinnedmartensite.

简介：TheelectrochemicalbehaviorofCu-Zn-Alshapememoryalloy(SMA)withandwithoutelectrolessplatedNi-PwasinvestigatedbyelectrochemicalmethodsinartificialTyrode'ssolution.TheresultsshowedthatCu-Zn-AlSMAengendereddezincificationcorrosioninTyrode'ssolution.TheanodicactivecurrentdensitiesaswellaselectrochemicaldissolutionsensitivityoftheelectrolessplatedNi-PCu-Zn-AlSMAincreasedwithNaClconcentrationrising,pHofsolutiondecreasingandenvironmentaltemperatureuprising.X-raydiffractionanalysisindicatedthataftersurfacemodificationbyelectrolessplatedNi-P,anamorphousplatedfilmformedonthesurfaceofCu-Zn-AlSMA.ThisfilmcaneffectivelyisolatematrixmetalfromcorrosionmediaandsignificantlyimprovetheelectrochemicalpropertyofCu-Zn-AlSMAinartificialTyrode'ssolution.

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