简介:Three-dimensionalfiniteelementmodelwasestablishedtosimulatetemperaturefieldsofT-jointtitaniumsheetsduringTIGweldingwithfiniteelementmethod(FEM)software.Temperaturedependentmaterialpropertiesandtheeffectoflatentheatwereconsidered.Atechniqueofelementbirthanddeathwasusedtosimulatetheprocessofweldedmetalfilling.DynamicvariationprocessoftemperaturefieldsduringTIGweldingwasachieved.Thesimulatedresultsagreedwellwiththemeasuredresults.
简介:氮(N)和磷(P)共同做锐钛矿TiO2nanosheets被与外国先锋做的高温度的P跟随的低温度的自我做的N-TiO2认识到。做过程的P能维持好TiO2nanosheets形态学与,这被发现暴露{001}方面。掺杂物的化学状态显示N和P原子在TiO2格子在O地点上代替O。与纯TiO2和做N的TiO2,N-P相比,共同做的TiO2nanosheets在可见轻政体展出更强壮的光吸收和染料分子的更高的降级率。提高的photocatalytic性质被归因于二个因素。一方面,N-P共同做能有效地从3.20~2.48减少TiO2的乐队差距?eV,在可见的光导致吸收的改进政体。在另一方面,存在暴露{001}TiO2nanosheets的方面能在反应导致photogenerated电子和洞的有效分离。
简介:Inthisstudy,atwo-stepheatingprocessisintroducedfortransientliquidphase(TLP)diffusionbondingforsoundjointswithT91heatresistantsteels.Atfirst,ashort-timehighertemperatureheatingstepisaddressedtomelttheinterlayer,followedbythesecondsteptocompleteisothermalsolidificationatalowtemperature.Themostcriticalfeatureofournewmethodisproducinganon-planarinterfaceattheT91heatresistantsteelsjoint.WeproposeatransitionalliquidphasebondingofT91heatresistantsteelsbythisapproach.Sincejointmicrostructureshavebeenstudied,wetestedthetensilestrengthtoassessjointmechanicalproperty.Theresultindicatesthatthesolidifiedbondmaycontainaprimarysolid-solution,similarcompositiontotheparentmetalandfreefromprecipitates.Jointtensilestrengthofthejointisnotlowerthanparentmaterials.Jointbend'sstrengthsareenhancedduetothehighermetal-to-metaljunctionproducinganon-planarbondlines.Nevertheless,thetraditionaltransientliquidphasediffusionbondingproducesplanarones.Bondingparametersofnewprocessare1260℃for0.5minand1230℃for4min.
简介:为了精确预测非理想条件下稀土金属溶剂萃取的平衡分配比,研究了溶于ShellsolD70中的P507溶剂对盐酸液中钇(Ⅲ)和铕(Ⅲ)的萃取平衡,建立化学基模型,并通过非线性最小二乘法确定萃取平衡常数。所建模型涉及了在低酸度区的离子交换反应和高酸度区的溶剂化萃取反应;模型还考虑了稀土金属与Cl-的配位反应,并用萃取剂的有效浓度代替[(HR)2],进而分别对水相和有机相(HR)2的非理想性加以修正。对稀土单元体系,在较宽的初始浓度范围内(稀土浓度最高至0.1mol/L,盐酸浓度0.07-3.00mol/L,萃取剂浓度0.25-1.00mol/L),由模型计算的稀土分配比与实验测得的数据吻合良好,验证了模型的有效性。对于稀土二元体系,该模型能以良好的精度对平衡分配比进行工程预测。
简介:Themicrostructureandmechanicalpropertiesoffrictionstirwelded2.5mm7050-77451aluminumalloynaturalaging72hand17520hwereinvestigated,respectively.Theuniaxialtensiletestshowedthatyieldstrength,tensilestrengthandelongationofthejoints17520hnaturalagingwereabout20%,12%and24%higherthanthosejointsnaturalaging72h.Hardnessprofileofnaturalaging17520hjointwitnessedsignificantenhancementinnuggetzone,comparedwith72hnaturalaging.Differentialscanningcalorimetry(DSC)andtransmissionelectronmicroscopy(TEM)testrevealedthatmoreGuinier-Prestonzone,η'andηphaseemergedinnuggetzoneasnaturalagingdurationincreased,highdensityofdislocationlocatedwithingrainboundaryinnuggetzoneofjointsnaturalaging72h.ItisconcludedthatnaturalagingwasfeasibletoenhancestrengthandplasticityofFSWjointssimultaneously.
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.