简介:LaserTreatmentofOxideDispersionStrengthenedAlloysShaWei(沙维)(DepartmentofMaierialsScicnceandMetallurgy,UniversityofCambridge,U...
简介:IntroductionIMI829titaniumaloyisakindofhightemperaturenearαaloy.Itsservicetemperatureisupto580℃.IthasbeenusedinRB211525E4en...
简介:MoleculardynamicssimulationwascarriedouttoinvestigatetheliquidandamorphousmicrostructuresofbinaryAgx-Rh(100-x)(x=25,50,75inatomfraction)alloys.SegregationfeatureofhomogeneousinteratomicbindingofAg-Rhliquidwasfoundandprobed,whichcanberetainedintoamorphoussolidsuponrapidcooling.Homogeneousbindingmayoccurwhenthedifferenceintheelementalatomicsizesislessthan10%.Theicosahedrainliquidbeforetheformationofamorphousstateexistinastablestateandthenetworkformedby1551-clustersinmoltenalloyswouldinhibitthecrystallizationanddiffusionofatoms.Ahigherdegreeof1551-clusterswillbefavorabletoformmetallicglasses.
简介:X-raydiffraction(XRD)anddifferentialscanningcalorimetry(DSC)wereemployedtoinvestigatetheinfluenceofNicontentonthecrystallizationofamorphousZr70Cu30-xNix(atomfrationin%)alloys,ExperimentalresultsshowthatwiththeNicontentincreasingtheactivationenergiesforcrystallizationofamorphousZr70Cu30-xNixalloysincreasecorrespondingly,indicatingthatthethermalstabilityisgreatlyimproved.AlltheDSCtracesofamorphousZr70Cu30-xNixalloysexhibittwoexothermicpeaks,suggestingthatthecrystallizationprocessviaadouble-stageticles,whilethesecondonecorrespondstotheprecipitaionofnano-scaleZr2Niphaseandcrystallizationofresidualamporphousphase,ThemechanismonthecrystallizationofamorphousZr70Cu30-xNixalloyswasdiscussed.
简介:GaxIn1-xAs1-ySbyalloyshavebeengrownbyatmosphericpressureMOCVDonn-GaSb(Te-doped)substrate.Thesohdcompositionwasdeterminedbyusingelectronmicroprobe.ThealloysofGalnAsSbwithcompositioninmiscibilitygapweresuccessfullygrown.TheopticalpropertiesofGaxIn1-xAs1-ySbylaverswerecharacterizedbythephotoluminescenceandtheinfraredabsorption.Thespectralresponsesofp+-GaInAsSb/p-GaxIn1-xAs1-ySby/n-GaSbdetectorsshowedwavelengthcutoffat2.4μmanddetectivity-D*=5×108cmHz1/2/Watroomtemperature.
简介:ThehydrogenstoragepropertiesofTi1.2Fe+xCa(x=1%,3%and5%inmassfraction)alloyswasinvestigated.ResultsshowthatthemodifiedalloyscanbeactivatedwithoutanythermaltreatmentatroomtemperatureduetotheadditionofCaandexcessTiinthealloys.HydrogenstoragepropertiesofthesemodifiedalloysvarywithCaamountandreactiontemperature.Inaddition,theinfluencemechanismoftheadditionofCaandexcessiveTiontheactivationbehaviorandhydrogenstoragecapacityofthealloyswasdiscussed.
简介:MicrostructureandtextureofTi-Nb-Sibasedalloys,preparedbywaterquenchingfromβ-phasefield,coldrollingandrecrystallizationheattreatmentfollowedbywaterquenching,wereinvestigatedintermsofopticalmicrostructureandanalysisofX-raypolefigureresult.Inas-quenchedsample,relativelyrandomdistributionofpolefigurewasdetectedwithoutshowingaspecifictexturecomponent.Inas-coldrolledsample,however,itisfoundwell-developedseveraltexturecomponentsconsistingofrotatedcube,α-fiberandγ-fibertexturecomponentswhicharefrequentlyobservedinbcc-structuredmetalsandalloyswerefound.Therefore,texturecomponentsdevelopedinthepresentalloysarecloselyrelatedtothedeformationofβ-phaseeventhoughsmallamountofα″phaseco-existinthemicrostructure.Inrecrystallizedsample,α-fibertexturecomponentisweaklydetectedwhiletheothertexturecomponents,rotatedcubeandγ-fibercomponents,appearstoberelativelyunchanged.Noadditionaltexturecomponentsweredetectedbesidesthosetexturecomponentsobservedinthecoldrolledsamples.
简介:Reerystallizafionofcold-roUeddiscontinuousprecipitationmicrostructurewhichhasfinelaminarstructureinanAl-40%7m(atomfraction)binaryalloyisinvestigatedbyopticalmicroscopy,SEMandTEM.Itisfoundthattherearetwokindsofrecrystallizationmechanisms:continuouscoarsening(CC)anddiscontinuouscoarsening(DC).Thelattercanbedividedintocoarseningmainlydrivenbystoreddeformationenergyatcolonyboundariesandslipbandsandtheonemainlydrivenbyboundaryenergyintheareawithlittledeformation.ItisshownthattheadditionofCucanretardthenucleationofcoarseningcellsandtheirgrowth.X-RaydiffractionanalysisindicatedthemetastablephaseCuZn4transformedintoequilibriumphaseAl4Cu3Znduringtheheatingprocess.
简介:作为La-Mg-Y系统的一个例子,方法怎么建立单个阶段的热力学的模型在热力学的优化的过程被介绍。答案阶段(液体,以身体为中心立方,以脸为中心立方、包装hexagonalclose、双六角形拥挤不堪)与Redlich-Kister方程被建模。Thecompound精力模型被用来在La-Mg-Y系统描述金属间化合的混合物的热力学的函数。在La-Mg-Y系统的混合物Mg_2Y,Mg_(24)Y_5,Mg_(12)La,Mg_(17)La_2,Mg_(41)La_5,Mg_3La和Mg_2La被当作公式(Mg,Y)_2(La,Mg,Y),Mg_(24)(La,Mg,Y)_4Y,Mg_(12)(La,Y),Mg_(17)(La,Y)_2,Mg_(41)(La,Y)_5,Mg_3(La,Mg,Y)并且Mg_2(La,Y)分别地。一个模型(La,Mg,Y)_(0.5)(La,Mg,Y)_(0.5)被使用由MgLa和MgY描述复合MgMformed以便在La-Mg-Y系统与CsCl类型结构(B2)应付在body-centeredcubic答案(A2)和MgM之间的顺序混乱转变。单个阶段的吉布斯精力在La-Mg被优化,躺并且由CALPHAD的La-Mg-Y系统技术。液体的Theprojection我们为La-Mg-Y系统的表面被预言。包括Mg,艾尔,Cu,Ni,Mn,Zn和稀土元素形成的36二进制代码和15三元系统的基于Mg的合金数据库元素在SGTE被安装标准。
简介:X-raydiffraction(XRD)anddifferentialscanningcalorimetry(DSC)wereusedtoinvestigatethecrystallizationprocessofamorphousAl90TMxCe10-x(atomfractionin%;TM=FeorNi;x=3,5)alloys.AgingeffectswereexaminedbyX-raydiffraction.ThestructurecorrespondingtotheprepeakfortheamorphousAl90Fe5Ce5alloyismorestablethantheamorphousmatrix,butitisnotstableforamorphousAl90Ni5Ce5alloyduringthefirstcrystallizationstageandevendecomposesatroomtemperature.AlthoughbothAl-NiandAl-Fehavestrongchemicalbonding,thecrystallizationonsettemperatureofamorphousAl-Fe-CealloysismuchhigherthanthatofamorphousAl-Ni-Cealloys,whichislikelycausedbythedifferentstabilityofthestructurecorrespondingtotheprepeak.ThecrystallizationonsettemperatureincreasesasCe/NiratioincreasesinamorphousAl90NixCe10-xalloys,whereasitdecreasesasCe/FeratioincreasesinamorphousAl90FexCe10-xalloys.AbetteratomicpackingproducesasCecontentincreasesbecauseofthesizemismatchinAlNi-CesystemsandasFecontentincreasesbecauseoftheincreasingFecentralstructuralunits.
简介:当一个中等稳定的阶段在内部反应期间外面被猛抛时,在散开地区以内的渗透的原子的行为能基于热力学的考虑被解释。在Ni-Cr合金at1125℃的内部nitridation期间向降水前面通过矩阵为“登高”证实渗透的种类的散开,6000块N_2压力被预言。氮的如此的行为对在瓦格纳的边界条件相反“对内部反应的s描述。与降水反应联系的一个体积变化导致了在合金表面和internalnitridation前面之间的一个压力坡度。应力消除主要由镍的运输发生了到气体/金属的接口。管子控制散开creep在nitriding期间是主导的压力住所机制冲淡在在流动NH_3+H_2煤气的混合物下面的700℃的Ni-Cr合金。
简介:Nuggetsplashduringaluminumalloysspotweldinghasadetrimentaleffectonweldnuggetintegrity,strengthanddurabilityoftheweldedjoints.Thisinvestigationisperformedtoidentifynuggetsplashfromvoltagesignalsbecausetheseareeasilyaccessibleon-line.Inthepresentwork,weproposeanovelmethodbasedonthewaveletpackettransformanditsenergyspectrumforpatternrecognitionofsplashsignal.Theresultdemonstratesthatthisnovelmethodismoreaccuracyandausefulwayofmonitoringthespotweldingquality.
简介:SolderingofLD31aluminumalloysusingSn-PbsolderpasteafterelectricbrushplatingNiandCucoatingswasnvestigated.ThetechnologyofelectricbrushplatingNiandCuwasstudiedandplatingsolutionwasdeveloped.Themicrostructureofthecoatings,solderedjointandfracturefacewereanalyzedusingopticmicroscopy,SEMandEDX.Theshearstrengthofsolderedjointcouldreachashighas26.83MPa.Theresultsshowedthatreliablesolderedjointcouldbeobtainedat230℃,theadhesionofcoatingsandLD31aluminumalloysubstratewashighenoughtobearthethermalprocessinthesoldering.
简介:Theeffectsoflow-CoAB5typehydrogenstoragealloyspreparedbyquenchingandannealingontheperformancesofMH-Nibatterieswereinvestigated,andthecharacteristicsofthelow-CoAB5typehydrogenstoragealloyswerecomparedwiththoseofthehigh-CoAB5typehydrogenstoragealloyaswell.Theresultsshowedthatthefasterthecoolingofthelow-Cohydrogenstoragealloyis,thebetterhomogeneityofthechemicalcompositionforthealloyandthelongercyclelifeofthebatteryare,buttheelectrochemicaldischargecapacityandhigh-ratedischargeabilityarereduced.Thehigh-ratedischargeabilityandchargeretentionofMH-Nibatteriesfortheconventionalas-castannealedlow-Cohydrogenstoragealloyweresuperiortothosefortherapidlyquenchedlow-Cohydrogenstoragealloyandthehigh-Cohydrogenstoragealloy,butalittleinferiorinthecyclelife.
简介:在二种铝锂alloys2090和2090+Ce的脱臼的微观结构借助于TEM技术被观察。到力量的8''和T_1precipitates的贡献被使用量的金属组织学的结果和微变丑的行为的分析独立计算;三角洲的共同加强的效果“andT_1猛抛被学习。结果证明三角洲共同加强的增加的关系“并且T_1根据1.4以近的山峰条件形成的q=,即,三角洲tau_p~(1.4)=三角洲字形物_(三角洲“)~(1.4)+三角洲字形物_(T_1)~(1.4);但是增加的关系是近似一种线性关系(q=1)以未成年的条件并且成为抛物线形式什么时候over-aged(q=2)。共同加强的增加的关系三角洲的贡献“并且显然依赖于老化时间的T_1is。
简介:InordertoimprovetheelectrochemicalcyclestabilityofLa-Mg-Nisystem(PuNi3-type)hydrogenstoragealloy,NiinthealloyswaspartiallysubstitutedbyM(M=Cu,Al,Mn).AnewLa-Mg-NisystemelectrodealloysLa0.7Mg0.3Ni2.55-xCo0.45Mx(M=Cu,Al,Mn;x=0,0.1)werepreparedbycastingandrapidquenching.Theeffectsofelementsubstitutionandrapidquenchingonthemicrostructuresandelectrochemicalperformancesofthealloyswereinvestigated.TheresultsbyXRD,SEMandTEMshowthatthealloyshaveamultiphasestructure,includingthe(La,Mg)Ni3phase,theLaNi5phaseandtheLaNi2phase.Therapidquenchingandelementsubstitutionhaveanimperceptibleinfluenceonthephasecompositionsofthealloys,butbothchangethephaseabundanceofthealloys.Therapidquenchingsignificantlyimprovesthecompositionhomogeneityofthealloysandmarkedlydecreasesthegrainsizeofthealloys.TheCusubstitutionpromotestheformationofanamorphousphaseintheas-quenchedalloy,andareversalresultbytheAlsubstitution.Theelectrochemicalmeasurementindicatesthattheelementsubstitutiondecreasesthedischargecapacityofthealloys,whereasitobviouslyimprovesthecyclestabilityofthealloys.ThepositiveinfluenceofelementsubstitutiononthecyclelifeofthealloysisinsequenceAl>Cu>Mn,andnegativeinfluenceonthedischargecapacityisinsequenceAl>Mn>Cu.Therapidquenchingsignificantlyenhancesthecyclestabilityofthealloys,butitleadstoadifferentextentdecreaseofthedischargecapacityofthealloys.
简介:ThestructureandelectrochemicalpropertiesofanewlowcobalthydrogenstorageelectrodealloysLa1-xLixNi3.2Co0.3Al0.3(0≤x≤0.2)wereinvestigatedwithadifferentadditionsofLiinreplacementofLa.WiththeincreaseofLicontentsthemaximumdischargecapacityincreasesfrom240mAh·g-1(x=0)to328.4mAh·g-1(x=0.1)andthecyclestabilityisimprovedcorrespondingly.ThecapacitydecaycanremaiN28.6%(x=0.2)after230charge/dischargecycles.Thehighratedischarge(HRD)abilityofthealloys(x≤0.1)isimprovedandthebestHRDis34.1%(x=0.1)underthedischargecurrentdensity1200mA·g-1.ItisfoundthatthepreparedalloysarebasicallycomposedofLaNi5asmatrixphaseandLaNi3assecondphase(x≤0.1).ButtheabundanceofLaNi3phasedramaticallydecreaseswithincreasingx.Whenx=0.2,anewphaseAl(NiCo)3isformed.