简介:镁为生物医学的应用作为革命可被细菌破坏的金属被建议了。然而,镁的腐蚀太快速,不能匹配织物愈合的率并且另外,展出局部性的腐蚀机制。因此为他们的实际使用控制镁的腐蚀行为是必要的。这篇论文包括地在代表性的镁的开发考察研究进步基于合金,包括象体积一样的Mg-Ca,Mg-Sr,Mg-Zn和Mg-REE合金系统金属性的玻璃。他们的微观结构,机械性质和腐蚀行为上的alloying元素的影响被总结。机械并且腐蚀性质做镁合金也演员组合金与那些比较被讨论。而且,这评论也盖住为生物医学的应用在镁合金上在可能减解的涂层的领域里执行的研究。钙磷酸盐和可被细菌破坏的聚合物涂层基于使用的不同准备技术被讨论。我们也在镁合金底层的腐蚀行为上比较不同涂层的效果。
简介:NanostructuredtitaniahavebeenintensivelyinvestigatedasanodematerialsofLi-ionbatteriesfortheirexcellenthighrateperformance.ThesizeeffectsofTiO2polymorphs(mainlyrutile,anataseandTiO2-B)ontheirelectrochemicalperformanceandthelatesteffortsinnanoengineeringtitaniaanodesthroughenhancingtheirionicorelectronictransportationorbotharereviewedinthiswork.Wesupposethatmicron-orsubmicronsizedporousstructuresassembledbyTiO2nanoparticles,nanowires/nanotubesornanosheetswithahighpercentageofexposinghighreactivefacetstogetherwithaconductivepercolatingnetworkareidealanodesnotonlyforhighratelithiumstoragebutalsoforhighpackingdensitiesoftheactivematerials.
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简介:Theadvancedfabricationofin-situdendrite/metallicglassmatrix(MGM)compositesisreviewed.Herein,thesemisolidprocessingandBridgmansolidificationaretwomethods,whichcanmakethedendriteshomogeneouslydispersedwithinthemetallicglassmatrix.Uponquasi-staticcompressiveloadingatroomtemperature,almostallthein-situcompositesexhibitimprovedplasticity,duetotheeffectiveblocktothefastpropagationofshearbands.Uponquasi-statictensileloadingatroomtemperature,althoughthecompositespossesstensileductility,theinhomogeneousdeformationandassociatedsofteningdominates.Highvolume-fractioneddendritesandnetworkstructuresmakein-situcompositesdistinguishinglyplasticupondynamiccompression.In-situcompositeexhibitshightensilestrengthandsoftening(necking)inthesupercooledliquidregion,sincethepresenceofhighvolume-fractioneddendriteslowerstherheologyoftheviscousglassmatrixathightemperatures.Atcryogenictemperatures,adistinguishingly-increasedmaximumstrengthisavailable;however,aductile-to-brittletransitionseemstobepresentbyloweringthetemperature.Besides,improvedtension—tensionfatiguelimitof473MPaandfour-point-bendingfatiguelimitof567MPaaregainedforZr58.5Ti14.3Nb5.2Cu6.1Ni4.9Be11.0MGMcomposites.Highvolume-fractiondendriteswithintheglassmatrixinduceincreasedeffectivenessonthebluntingandpropagatingresistanceofthefatigue-cracktip.Thefracturetoughnessofin-situcompositesiscomparabletothoseofthetougheststeelsandcrystallineTialloys.Duringsteady-statecrack-growth,theconfinementofdamagebyin-situdendritesresultsinenhancementofthetoughness.
简介:Variousfunctionalgroupshavebeensuggestedtoplayessentialrolesonbiomineralizationofcalciumcarbonate(CaCO3)innaturalsystem.2Dand3DmodelsofregularlyarrangedfunctionalgroupshavebeenestablishedtoinvestigatetheireffectonCaCO3crystallization,Thismini-reviewsummarizestherecentprogressandthefuturedevelopmentisprospected.
简介:Self-lubricatingcoatingshavebeenwidelyusedtoreducefrictioninmovingmachineassemblies.However,thetribologicalperformanceofthesecoatingsisstronglydependentontheservicetemperature.Inthispaper,anextensivereviewpertainingtotheinfluenceofoperatingservicetemperatureontribologicalperformanceofself-lubricatingcoatingshasbeencarriedout.Basedontheeffectivelubricatingtemperaturerange,theself-lubricatingcoatingsdevelopedinthepasthavebeendividedintothreegroups:lowtemperaturelubricantcoating(from-200℃toroomtemperature),moderatetemperaturelubricantcoating(fromroomtemperatureto500℃)andhightemperaturelubricantcoating(〉500℃).Ideasconcerningpossiblewaystoextendtheoperatingtemperaturerangeofself-lubricatingcoatingshavebeenpresentedasfollows:hybridizedtribologicalcoating,adaptivetribologicalcoatings,anddiffusionratelimitedsolidlubricantcoating,inaddition,anewself-lubricatingcoatingformulationforpotentialapplicationatawideoperatingtemperaturerangehasbeenproposed.
简介:奥氏体的热抵抗钢为先进supercritical锅炉,核反应堆,超级加热器和化学反应堆被认为候选人材料同样重要由于他们高力量的有利联合,腐蚀抵抗,完美的机械性质,可使用性和低费用。因为钢的降水行为将在在提高的温度的长期的服务期间导致机械性质的恶化,在钢的微观结构澄清第二等的阶段的进化是必要的。这里,在降水行为和变粗的机制的最近的进步的一篇摘要各种各样在奥氏体的钢在老化期间猛抛被做。各种各样的第二等的阶段在服务条件下面被形成,象MXcarbonitrides一样,M23C6碳化物,Z阶段,西格马阶段和洗分阶段执行。这被发现M23C6碳化物比MXcarbonitrides的高得多。以便理解热变丑机制,一个组成的方程能被建立,并且因此获得了处理地图对优化热处理参数有益,导致改进了热处理钢的性质。
简介:Inthepastfewdecades,manynovelnon-metaldopedZnOmaterialshavedevelopedhastyinterestduetotheiradaptablepropertiessuchaslowrecombinationrateandhighactivityunderthesolarlightexposure.Inthisarticle,wecompiledrecentresearchadvancesinnon-metal(S,N,C)dopedZnO,emphasizingontherelatedmechanismofcatalysisandtheeffectofnon-metalsonstructural,morphological,opticalandphotocatalyticcharacteristicsofZnO.ThisreviewwillenhancetheknowledgeabouttheadvancementinZnOandwillhelpinsynthesizingnewZnO-basedmaterialswithmodifiedstructuralandphotocatalyticproperties.
简介:在在参考书在中等Mn钢上总结相关研究以后,张力的性质上的二个新目标被定义。一个人两个都是那导致转变(旅行)并且导致双胞胎的粘性(缇)能与一个相对低的Mn内容为钢被认识到,它与更高的Mn内容展出类似的张力的性质到古典缇钢。其它将完成超离频的最终的张力的力量(>1.5?GPa)没有牺牲formability。达到这些目标,新设计策略为作文和处理线路被提出。特别地,因为前者能经由部分再结晶与不同形态学和尺寸生产保留的奥氏体谷物的混合物,温暖的滚动被采用而不是平常的热/冷的滚动过程。因而,保留的奥氏体谷物有大量技工稳定性以便他们能在变丑期间逐渐地转变到马氏体,导致提高的旅行效果然后改进技工性质。最后,它在在实验室生产这些指向的中等Mn钢被接替,他们中的一些甚至比我们的期望展出更好张力的性质。
简介:煤苍蝇灰是为精力生产在煤的燃烧期间产生的一个工业副产品。由于增加煤电源的年度消费和煤苍蝇灰的严肃的潜在的环境威胁,关于煤苍蝇灰的利用的研究的可观的数量全球被承担了。玻璃化似乎是为再使用这工业废物的最有希望的选择之一。这篇论文作为原料用煤苍蝇灰给出唯一的高效眼镜陶艺的生产的短概述。对为从煤苍蝇灰和主要水晶阶段,相应性质和那些材料的可能的用法的眼镜陶艺的合成的方法论的详细描述被介绍。调查揭示了那变换的煤苍蝇灰进高效眼镜陶器的材料是一条有希望的新途径改进这个工业副产品的利用。这变换不仅与处理减轻这些问题而且把废物材料变换成高增值可销售的商品。
简介:这评论调查Mg和Mg合金的当前的申请限制。妨碍是的可被细菌破坏的Mg合金的申请的关键问题植入是他们的快降级率和生物考虑。我们在基于Mg的合金的性质上讨论了一些选择alloying元素增加的效果,特别在人的滋养的元素(Zn,Mn,Ca,Sr)。不同谷物尺寸,阶段成分和分布因而影响Mg合金的机械性质。溶液加强并且降水加强被alloying元素的增加提高,通常改进机械性质。而且,热工作过程能也改进机械性质。不同的处理的步的联合被建议在基于Mg的合金的制造被收养。这些基于Mg的合金的腐蚀性质在vitro并且在vivo被测量了。降级机制也以包围纸巾的腐蚀类型,率,副产品和回答被讨论。而且,临床的反应和要求可能减解植入被介绍,特别为滋养的元素(Ca,Mn,Zn,Sr)。这评论提供与不同Mgalloying元素有关的信息并且介绍答应理想的候选人植入。
简介:Themartensitic/ferriticsteelshavebeenusedasboilerandturbinematerialsinpowerplants,andalsobeenselectedaspotentialmaterialsforstructuralmaterialsinnuclearreactors.Inthispaper,thekineticanalysisofthemartensiteformationandmicrostructuralcontrolofhigh-Crmartensitic/ferriticsteelsarereviewed.Amodularapproach,incorporatingFisherpartitioningnucleationandanisotropicgrowthforimpingement,wasproposedtodescribethemartensiteformationkineticsunderdifferentcoolingrates.Thekineticanalysissuggestedathermal-activatedgrowthfeatureoccurringduringthemartensitictransformationofmartensiticsteels.Themicrostructurecanbetunedbycompositionoptimizationandvariouscombinationsofheattreatmentparameters(temperature,time,severeandminordeformation).Fortheapplicationinpowerplant,thepotentialofboundary-design,refinementoforiginalaustenitegrainsizeandthefinalmartensiticlath,pinningeffectofstablecarbides,inimprovingtheperformancesofmartensitic/ferriticsteelsatelevatedtemperaturesshouldbeinvestigatedmorethoroughly.Furthermore,effortsshouldbemadetoexploretheeffectsofretainedausteniteontheimprovementofhigh-temperaturecreepstrength.Fortheapplicationofnuclearplants,attemptsshouldalsobemadetoproduceFepowderswithuniformlydistributedoxideparticlesbychemicalreactions.