简介：Fe3AlandCr18-Ni8steelwerebondedinvacuumandaninterfacewasformedbetweenFe3AlandCr18-Ni8steel.Stressdistributionatthediffusion-bondedinterfacewasresearchedbynumericalsimulationandfiniteelementmethod(FEM).TheresultsindicatedthatthepeakstressappearedattheinterfacenearCr18-Ni8steelside.Thisisthekeyfactortoinducecrackatthisposition.Withtheenhancementofheatingtemperature,thepeakstressatthebondedinterfaceincreases.Whenthetemperatureis1100℃,thepeakstressisupto65.9MPa,whichisbiggerthanthatat1000℃by9.4%.Inaddition,thepeakstressbecomesbiggerwiththeincreaseofthethicknessofbasemetalfrom1mmto8mm.Whilethethicknessismorethan8mm,thepeakstressvariesslightlywiththechangeofthethickness.

简介：ESD(electrosparkdeposition)isapromisingprocesstoproducehardandwear-resistingcoatingsonmetallicsubstrates.InthispapermicrostructureandinterfacialcharacteristicsoftheWC92-Co8coatedontitaniumandcarbonsteelarepresented.Ametallurgicalbondingbetweenthecoatingandsubstrateisobtained.TheTielementwasfoundtodistributeinWC92-Co8atthemetalpool,aswellastheinterfacebydiffusion.SomenewphaseswereproducedinthecoatinglayerduetothechemicalreactionduringtheESDprocess.ExperimentalobservationandthermodynamicanalysiswereutilizedtostudythemechanismofESD.

简介：TiC/Cr18Ni8steelbondedcarbidesweresynthesizedbyvacuumsinteringwithmixedpowdersofiron,ferrotitanium,ferrochromium,colloidalgraphiteandnickelasrawmaterials.Themicrostructureandmicrohardnessofthesteelbondedcarbideswereanalyzedbyscanningelectronmicroscope(SEM),X-raydiffraction(XRD)andRockwellhardometer.ResultsshowthatthephasesofsteelbondedcarbidesmainlyconsistofTiCandFe-Cr-Nisolidsolution.ThesynthesizedTiCparticlesarefine.Mostofthemarenotmorethan1μm.Withtheincreaseofsinteringtemperature,theporosityofTiC/Cr18Ni8steelbondedcarbidesdecreasesandthedensityandhardnessincrease,butthesizeofTiCparticlesslightlyincreases.Underthesamesinteringconditions,thedensityandhardnessofsteelbondedcarbideswithC/Tiatomicratio0.9arehigherthanthosewithC/Tiatomicratio1.0.TheTiCparticleswithC/Tiatomicratio0.9aremuchfinerandmorehomogeneous.

简介：Thefatiguepropertiesoffrictionstirwelded(FSW)buttjointandbasemetalofMB8magnesiumalloywereinvestigated.ThecomparativefatiguetestswerecarriedoutusingEHF-EM200K2-070-1AfatiguetestingmachineforbothFSWbuttjointandbasemetalspecimens.ThefatiguefractureswereobservedandanalyzedusingascanningelectronmicroscopeofJSM-6063LAtype.TheexperimentalresultsshowthatthefatigueperformanceoftheFSWbuttjointofMB8magnesiumalloyissharplydecreased.Theconditionalfatiguelimit(2×10~6)ofbasemetalandweldedbuttjointisabout77.44MPaand49.91MPa,respectively.Theconditionalfatiguelimit(2×10~6)oftheweldedbuttjointis64.45%ofthatofbasemetal.Themainreasonsarethattheweldingcanleadtostressconcentrationintheflasharea,tensileweldingresidualstressintheweldedjoint(Theresidualstressvaluewas30.5MPa),aswellasthegrainsizeisnotuniformintheheat-affectedzone.Thecleavagestepsorquasi-cleavagepatternspresentonthefatiguefracturesurface,thefracturetypeoftheFSWbuttjointbelongstoabrittlefracture.

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简介：近期,重庆市发改委公布了《重庆市2014年市级重点项目名单》（以下简称《名单》）,大量与城市发展、民生改善密切相关的重点项目惹人注目。市发改委表示,今年重庆市全年计划实施重点建设项目526个,总投资2万亿元,其中年度计划投资3500亿元,

简介：中国铁路总公司4月30日召开电话会议，再度调整今年的铁路固定资产投资计划，将今年铁路投资总额上调至8，000亿元人民币．仅次于2010年8426．52亿元的历史顶点。新项目从年初计划的44个飙升至64个，今年新投入运营的线路要确保达到7000公里以上，

简介：GB／T15579．5-2005《弧焊设备安全要求第五部分：送丝装置》和GB／T15579．7-2005《弧焊设备安全要求第七部分：焊炬（枪）》（以下简称新标准）已于2005年12月1日正式实施。自新标准实施之日起．JB/T9533-1999《焊机送丝装置：技术条件》、JB／T9526-1999《TIG焊焊炬技术条件》和JB／T9532-1999《MIG／MAG焊焊枪技术条件》（以下简称旧标准）废止。

简介：<正>由中华全国总工会、科学技术部、人力资源和社会保障部联合举办的第三届全国职工职业技能大赛于圆满地落下帷幕。大赛共设焊工、钳工、维修电工、速录师、数控车工、数控铣工、加工中心操作工、数控机床装调维修工8个工种的比赛,并产生了35名优秀选手、10个团体名次奖和8个优秀组织奖。2009年11月9日