高温液态合金在真空环境下成分演化及烟雾形成机制分析.pdfVIP

QuestionNo.1

AliquidNi-Alalloysphereislevitatedwithaninductioncoilinanexcellentvacuumchamberat

1500C.Stirringofthedropletisintensesothatthemeltcompositionisuniformatanytime.Ifthe

spherehasaradiusofonecmandaninitialAlmolefractionof1%.Deriveanexpressionwhich

shoulddescribetheAlcontentofthedropletatanytime.Identifyanypropertiesorparameters

required.Stateyourassumptions.

Ifthevacuumwerepoor,asmoke(orfog)wouldbeobservedaroundthedroplet.Explainthe

mechanismofsmoke(orfog)formation.

IstherateofAllosshigherintheexcellentvacuumorupontheformationofsmoke?Why?

QuestionNo.2

Discusstheuseofstatisticalmechanicsforthecalculationofthermodynamicpropertiessuchas

entropy,internalenergy,andfreeenergy.Illustrateyouranswerbyreferencetoasimplediatomic

molecule.

QuestionNo.3

(a)(i)Demonstratethatthevariationofthechemicalpotentialofacomponentinamixturewith

appliedpressureatconstanttemperatureisgivenbythepartialmolarvolumeofthecomponentin

themixture.1.e.

u1TV1



P

(ii)Converttheprecedingexpressiontofindanexpressionfor:

lna1

T



P

Wherea1istheactivityofcomponent1withrespecttopure1.

(b)Foraparticularbinarysystem(manyalloysystemsexhibitthisbehavior)“retrograde

solubility”isestablishedasshownintheaccompanyingsketch.Notethatthesolubilityofin

isaminimumatTr,the“retrogradetemperature”.SketchGibbsenergy-compositioncurves

forthebinarysystematTrandslightlybelowTr.Canyoudrawanyconclusionsabouttherelative

stabilityofatlowertemperatures?

问题1

液态镍铝合金球在1500℃的优质真空室中通过感应线圈悬浮。液滴的剧烈搅拌使得熔体成

分在任何时候都是均匀的。如果球体的半径为1cm，初始Al摩尔分数为1%。推导一个

表达式来描述任意时刻液滴的Al含量。确定所需的任何属性或参数。陈述你的假设