超細鎢粉熱壓燒結(jié)致密化過程計算機模擬.pdf

1、上海大學碩士學位論文超細鎢粉熱壓燒結(jié)致密化過程計算機模擬姓名：賀新福申請學位級別：碩士專業(yè)：凝聚態(tài)物理指導(dǎo)教師：王傳珊尹邦躍20070501上海大學碩士學位論文ABSTRACTTungsten(W)hasthehighestmeltingpointofallmetals(3410“(2)，thelowestvaporpressureandagoodthermalconductivityithasbeenselectedasthearmo

2、rmaterialofIntemationalThermonuclearExperimentReactor(ITER)forthediverterbaffleareaRecentlyEuropeanUnionhaschoosingtungstenasthefirstwallmaterialsofDemonstrationreactor(DEMO)，whichfacedtheplasmaHoweverfortungsten’S11i曲es

3、tmeltingpointandlowestdiffusioncoefficient，itisverydifficultforpuretungsten’SsinteringSopreparationofpuretungsten、Ⅳithlli曲densitymicro—grainandhighphysicalpropertiesmakeagreatchallengeTheinfluenceoftheeffectivepressure，p

4、articlesizeanddistribution，impuritiesandgraingrowthduringthehotpressingprocessweremainlydiscussedinthispaperonthebasisofthesuperfinetungstenpowders’hotpressingpracticeandcomputersimulationAtfirst，thecomplicatedchangesoft

5、hematerialsduringthesinteringprocessareintroduced，thestate—ofthe—artaboutsinteringsimulationisprovided，andthecharacteristicoftungstenasthearmormaterialisalsodiscussedThenecessityandfeasibilityoftheresearchwereprovidedInt

6、hesecondpart，thesinteringmechanismswereintroducedandsomehotpressingmodelshavereviewedThenadensificationmodelcoupling、析tllgraingrowthbasedontheenergydissipationtheoryandvisco—plasticityWasdeveloped，andthemicroscopicviscos

7、itymodulesofthemetalpowderswhichdominantdiffusionmechanismsareboundarydiffusionandsurfacediffusionwerebrieflydiscussedItdemonstratedthattheviscositymodulesarefunctionsofrelativedensitygrainsizeandapparentviscosityButinFr

8、enkel’SsolidviscositytheorytherelativedensityandgrainsizewerenotconsideredTungsten’SgraingrowthmodelsduringsinteringalsointroducedinthispaperandRMGerman’SexperientialmodelWasimprovedinordertomodelingthesuperfinetungstens