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:一、石墨烯概述石墨烯是一种由SP2杂化轨道组成且只有一个碳原子厚度的六角型平面薄膜[1]。石墨烯从被发现到其性能得到重视、直至目前已进入了快速发展阶段:2004年,英国曼彻斯特大学AndreK.Geim带领研究成员从石墨中发现了世界上最薄的材料“石墨烯”,并对其特有的属性展开深入研究[2]。2010年10月,AndreK.Geim和KonstantinNovoselovAndre因其突破性实验而成为诺贝尔物理学奖的获得者。自此,石墨烯进入了高速发展阶段,并凭借其优异的特性逐渐走入世界各国学术研究者的眼界,即将在各大重要领域掀起一场新的革命。
简介:PositronannihilationbehaviorshavebeenstudiedinthesinglephaseNd2Fe14BmagnetandthenanocompositeNd2Fe14B/α-Femagnet,preparedbymeltspinning.Theresultsshowedthatthenumberofvacancy-clusteratgrainboundariesincreaseswithincreasingannealingtemperatureforthebothtypesofmagnets.Theincreaseofthiskindofdefectcanimprovethecoercivityof