简介:Fe-0.2C-l.5Si-l.67Mn钢受到熄灭并且划分(Q&P)进程,和在在提高的划分温度的马氏体和奥氏体之间的接口移植被观察。接口迁居在constrainedparaequilibrium(用户终端设备)被排除模型。基于“端点”由用户终端设备模型预言接口移植的热力学的条件被分析,也就是说,在在铁酸盐(martenisite)和奥氏体的铁的化学势的差别生产铁原子的驱动力从一个阶段移居到另外的阶段。另外,接口迁居罐头改变奥氏体部分;作为结果,在划分温度的奥氏体部分可能在通过接口移植熄灭温度比那高,但是这现象不能被用户终端设备模型解释。
简介:LowcarbonsteelswithBandPadditionswereremeltedbyelectromagneticlevitationandsolidifiedinavacuumdroptube.Thedropletvolumesweresettobe2mm×2mm×2mm(TM)and5mm×5mm×5mm(FM),respectively.Themicrostructureofrapidlysolidifiedsteeldroplets(cooledinsiliconoil)withPandbothBandPadditionwasobserved.ThemicrostructuresofB-bearingdropletsamplesweremoreuniformthanthoseofB-freeones,forbothTMandFMsamples.Thedistributionof℃andPalongthediameterofeachsamplewasdetected.Thewell-distributionof℃andPwasdetectedinB-bearingdropletsamples.SoitcouldbededucedthatBwasalsowelldistributedinthesteels.ItwasBatomsthatpromotedthewell-distributionof℃andP,whichfurtherimprovedtheuniformityofmicrostructureundertheconditionofrapidsolidification.Themicro-hardnessofBbearingsampleswashigherthanthatofB-freesamples,andthehardeningmechanismwasdiscussedindetail.
简介:PositronannihilationbehaviorshavebeenstudiedinthesinglephaseNd2Fe14BmagnetandthenanocompositeNd2Fe14B/α-Femagnet,preparedbymeltspinning.Theresultsshowedthatthenumberofvacancy-clusteratgrainboundariesincreaseswithincreasingannealingtemperatureforthebothtypesofmagnets.Theincreaseofthiskindofdefectcanimprovethecoercivityof
简介:MoleculardynamicssimulationusingauniversalforcefieldhasbeenemployedtodeterminethediffusioncoefficientsofO2andNa2SO4vaporintoB2O3andSiCfrom700Kto1273K,respectively.Einsteindiffusionwasobservedina250~300pssimulation.ThediffusioncoefficientfortheO2rangefromabout9.279×10-9cm2/sforB2O3to2.275×10-10cm2/sforSiCataloadingof32moleculespersimulationbox,thatfortheNa2SO4vaporrangefromabout9.888×10-7cm2/sforB2O3to1.837×10-10cm2/sforSiCataloadingof8moleculespersimulationbox.EnvironmentpropertiesofC/SiCcompositewillbeincreasedviatheB2O3preventingthediffusionofO2andNa2SO4vaporintothepyrolyticinterphaseandcarbonfibers.
简介:有alloying原子X=C,B,N,O和空缺的镁和它的合金的概括叠的差错(GSF)精力和表面精力用第一原则的方法被调查了。叠的差错精力上的alloying原子和空缺的占优势的减少效果在slip飞机附近在第一层从他们的位置被结果,这被发现。叠的差错精力是将近与纯镁一样当alloying原子和空缺被放在时第二,第三,第4,第5和第6层。O强烈减少Mg的GSF精力,这被显示出。alloying原子C,B和N增加表面精力,但是O和空缺减少Mg的表面精力。Mg和Mg合金的韧性被使用在表面精力和不稳定的叠差错精力之间的比率基于瑞斯标准讨论了。
简介:ExperimentswerecarriedouttostudytheinfluenceofsurfaceconditiononexpulsionduringthespotweldingofAZ31BMgalloy.AgeneralelectricalcontactresistancetheoryforconductiveroughsurfacesandtherelationbetweenmaximumtemperatureTminthecontactandvoltage-dropVacrossinterfaceoftwosurfaceswereemployedtounderstandthereasonofexpulsioninMgalloyspotwelding.Themainreasonofexpulsionisthatthehighelectricalcontactresistanceinducedbylargeroughnessofthesurfaceandoxidefilmcoveredonthesurfaceleadstolocalmeltingofmetalintheinterfaceoftwosurfaces,andliquidmetalofthelocalareaejectedfromthespecimenunderelectrodeforceformsexpulsion.