学科分类
/ 1
8 个结果
  • 简介:Athermalconductionmodelisappliedtospeedupthenumericalanalysisofthetemperaturedistributionandtheweldpoolgeometryoffullpenetrationingastungstenarc(GTA)welding.Withconsideringbothtopandbottomfreesurfacedeformationoffull-penetratedweldpool,three-dimensionalweldpoolwithmeltingfrontandsolidificationfrontispredicted.Weldingexperimentsareconductedtomeasurethemeltingfrontcurvesatthetopsurfaceandthelongitudinalsectionoftheweld.Itshowsthatthepredictedandmeasuredresultsareingoodagreement.

  • 标签: 钨电极惰性气体保护焊 GTA焊接 熔池 焊接正面 全焊透 数值分析
  • 简介:Reerystallizafionofcold-roUeddiscontinuousprecipitationmicrostructurewhichhasfinelaminarstructureinanAl-40%7m(atomfraction)binaryalloyisinvestigatedbyopticalmicroscopy,SEMandTEM.Itisfoundthattherearetwokindsofrecrystallizationmechanisms:continuouscoarsening(CC)anddiscontinuouscoarsening(DC).Thelattercanbedividedintocoarseningmainlydrivenbystoreddeformationenergyatcolonyboundariesandslipbandsandtheonemainlydrivenbyboundaryenergyintheareawithlittledeformation.ItisshownthattheadditionofCucanretardthenucleationofcoarseningcellsandtheirgrowth.X-RaydiffractionanalysisindicatedthemetastablephaseCuZn4transformedintoequilibriumphaseAl4Cu3Znduringtheheatingprocess.

  • 标签: 冷变形工艺 微观结构 AL-ZN 铝基合金 重结晶
  • 简介:"GasTransmittingFromWesttoEastProject"issignificant.Itshouldensuretheweldingqualityandsafetyofpipeline.Thetaskisveryarduoustoguaranteethequalityoftheprojectintheconditionoflongline,complexweatherandgeologyfeatures.Inthispaper,theweldingcoldcrackingsusceptibilityofdomesticX-70pipelinesteeladoptedbytheproject,whichisoneofthemostinterestingquestionsofweldingqualityaboutpetrolpipeline,wasstudiedbymeansofobliqueY-groovecrackingtest.Thecrackratioofsurfaceandsectionwastestedundertheconditionsofdifferentweldingmaterialsandpreheattemperature.TheX-70pipelinesteelhasgoodcrackresistance.Theresearchhasimportantvaluefortheconstructionoflarge-scalepipelineengineeringandtheapplicationofdomesticX-70pipelinesteel.

  • 标签: 预加热 倾斜 Y形开槽断裂测试 X-7D管道钢 冷裂磁化率 焊接质量
  • 简介:ThemicrostructuresandcrystallizationbehaviorofTi–47at%Ni–3at%Feshapememoryalloywireundertheconditionofseverecolddrawingatroomtemperatureanddifferentpost-deformationannealingprocesseswereintensivelyinvestigatedusingtransmissionelectronmicroscope(TEM)anddifferentialscanningcalorimetry(DSC).ItisindicatedthattheamorphousphaseisdominantintheTi50Ni47Fe3wireafterthecolddrawingof78%arealreduction.Thecriticaltemperatureforrecrystalizationisdeterminedatabout300°C.Theaveragegrainsizegrowsfrom7upto125nmwhenannealingtemperaturerisesfrom300to500°C.Post-deformationannealingprocessexertssignificantinfluenceonthecrystallizationtemperaturewhichclimbsupwiththeincreaseofannealingtemperature.

  • 标签: 结晶行为 严寒 透射电子显微镜 平均晶粒尺寸 退火工艺 扫描量热法
  • 简介:为在水样品的踪迹水银的分析的一个新方法被开发,基于用象由冷蒸汽的稳固的阶段提炼之物和决心的修改dithizone的纳米钛二氧化物(TiO2)的preconcentration/separation的联合原子吸附spectrometry(CVAAS)。Dithizone与酒精被溶解并且在缩放nano的TiO2粉末的表面上装载了由激动人心。修改dithizone的nanoparticles上的Hg2+的静态的吸附行为详细被调查。为Hg2+的优秀吸附比率能与15min,和3.5摩尔的5mL的一摆动时间在78的pH范围被获得,这被发现

  • 标签: 分析化学 水银 固体相位萃取 氧化钛纳米颗粒 吸附作用