简介:AdditionofAl-5Ti-1Balloytomoltenaluminumalloyscanrefineα-Algrainseffectivelyandtherebyimprovetheirstrengthandtoughness.TiAl3andTiB2inAl-5Ti-1Balloyarethemainsecondary-phaseparticlesforrefinement,whiletheunderstandingontheeffectoftheirsizesonα-Algrainrefinementcontinuestobefragmented.Therefore,Al-5Ti-1Balloyswithvarioussizesandmorphologiesofthesecondary-phaseparticleswerepreparedbyequalchannelangularpressing(ECAP).Evolutionofthesecondary-phaseparticlesduringECAPprocessandtheirimpactonα-AlgrainrefinementwerestudiedbyX-raydiffractionandscanningelectronmicroscope(SEM).ResultsshowthatduringtheECAPprocess,micro-cracksfirstlyappearedinsideTiAl3particlesandthengraduallyexpanded,whichresultedincontinuousrefinementofTiAl3particles.Inaddition,micro-distributionuniformityofTiB2particleswasimprovedduetotheimpingementofTiAl3particlestoTiB2clustersduringdeformation.ExcessivelylargesizesofTiAl3particleswouldreducethenumberofeffectiveheterogeneousnucleusandthusresultedinpoorgrainrefinementeffectiveness.Moreover,excessivelysmallTiAl3particleswouldreduceinhibitoryfactorsforgraingrowthQandweakengrainrefinementeffectiveness.Therefore,anoptimalsizerangeof18-22μmforTiAl3particleswassuggested.
简介:双相不锈钢1Cr18Ni11Si4AlTi由前苏联研制,目前在我国某些特殊行业中有重要的作用。根据我国现有标准GJB2294—95和GB/T1220—92组织生产,发现按标准中现行成分设计、热处理制度生产的产品与标准要求的力学性能(屈服强度σ0.2)需达到的规定值存在较大差异,很难达到所需要的屈服强度。通过完善相关成分和工艺参数,获得了满意的金相组织和优良的综合力学性能。通过试验探讨了生产实际与标准中的部分规定存在的差距。
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简介:Intrinsiccarrierconcentration(ni)isoneofthemostimportantphysicalparametersforunderstandingthephysicsofstrainedSiandSi1-xGexmaterialsaswellasforevaluatingtheelectricalpropertiesofSi-basedstraineddevices.Uptonow,thereportonquantitativeresultsofintrinsiccarrierconcentrationinstrainedSiandSi1-xGexmaterialshasbeenstilllacking.Inthispaper,byanalyzingthebandstructureofstrainedSiandSi1-xGexmaterials,boththeeffectivedensitiesofthestatenearthetopofvalencebandandthebottomofconductionband(NcandNv)at218,330and393KandtheintrinsiccarrierconcentrationrelatedtoGefraction(x)at300KweresystematicallystudiedwithintheframeworkofKPtheoryandsemiconductorphysics.ItisfoundthattheintrinsiccarrierconcentrationinstrainedSi(001)andSi1-xGex(001)and(101)materialsat300KincreasessignificantlywithincreasingGefraction(x),whichprovidesvaluablereferencestounderstandtheSibasedstraineddevicephysicsanddesign.
简介:利用水热法制备了不同Ni含量的ZnO(Zn1-xNixO)稀磁半导体材料,通过XRD、FESEM和VSM对产物的结构、形貌及磁性进行了分析与测试,探讨了反应时间对Zn1-xNixO材料结构及磁性的影响。结果表明,反应时间显著影响Zn1-xNixO的结构与磁性,随着反应时间的延长,样品的结晶质量下降,形貌由六方棒状结构转变为片状结构,同时磁性减弱。
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简介:Withpositronannihilationradiationonedimensionangular-correlationdevice,itismeasuredthatpositronannihilationradiationonedimensionangular-correlationcurvesofpolycrystalsodiumionconductorNa5Y1-xCrxSi4O12(NYCS)system.Afterelectronmomentumdistributioncurvesarenormalized,linearparametersarecalculated.TheparametersH,WandSshowthechangeofNa+ionvacancyconcentrationinNYCSseriessamples.TheresultsshowthatparametersH,WandSofonedimensionangular-correlationcurvesofthosesamplesvarygreatlywithCr2O3contents.WithCr2O3contentincreasing,HandSparametersincrease,butWdecreases,andreachesextremesatx=0.05;thenwithCr203addingcontinually,parametersHandSdecreasegradually,parameterWincreasesgradually.Thisshowsthat,inaddtiontoCr2O3,theconductivityhascloserelation
简介:导致流动的腐蚀在于电气化学、机械的components.Thepresent纸有到估计了氯化物离子的角色并且在为是的AA5083-H321铝镁合金的导致的腐蚀广泛地在高速度的船,潜水艇,气垫船,和脱盐系统的构造使用了的流动的电气化学的部件溶解了氧,在NaClsolutions.Electrochemical,测试在0,2,5,7和10m/s的流动速度被执行,在有不同氯化钠集中的充气并且使除去空气的NaCl答案。结果证明在水动力学条件下面的氧减小的高率在表面上在坑的密度引起增加。在流动条件下面的氯化物离子集中的增加加速阳极的反应的率,但是没在阴极的反应上有影响。在当前的工作,因此,在流动条件下面,由于在坑内的腐蚀产品的消除,合金的腐蚀电阻被增加,这被发现。