化學細化法制備鋁合金的研究.pdf

1、浙江大學碩士學位論文化學細化法制備鋁合金的研究姓名：陳延紅申請學位級別：碩士專業(yè)：材料學指導教師：嚴密2001.3.1塑塹查堂堡主堂垡堡莖一一一——ABSTRACTSemi—solidprocessingisapromisingtechnologyinthefieldofmaterialsscienceandengineering，duetOitslowworkingtemperatures，lessdamagetomolds，refi

2、nedmicrostructures，goodmechanicalperformanceandhighproductivityThefabricationofvarioussemi—solidslurrysisthekeyfortherealizationofsemi—solidformingAmongvariouswaystoprocesssemisolidslurrys，chemicalrefiningpossessesalotof

3、advantages，suchasnotrequiringcomplexstirringsystemsInthispaperrecentresearchresultsonthesemi—solidprocessingandrheology，aswellasvariousrefiningmechanismsofaluminumaresummarizednIecrystallgraphicrelationshipsbetweenalumin

4、umandsomemetalliccompoundsorREelementsarediscussedTheapparentviscositiesandmierostructuralevolutionduringcoolingareinvestigatedTheeffectsofTi，B，K2TiF6，andgraphiteonthemicrostructureandviscosityofhypoeutecticAISialloysare

5、alsostudiedThemainresultsareasfollows：(1)SomeorientationrelationshipsexistbetweenTiAl3andaluminum，makingTiAl3agoodrefinerofaluminumZrAl3Canbeasubstrateforaluminumnucleation，whileZrB2iSapoorcatalystWhenZrpresentsinmoltena

6、luminumtogetherwithTi—B，it“poisons’’theTi—Brefinet(2)FromtheviewpointofgeometryREelementsCannotbethenucleationsubstrateofAlREmayrefineAIbyrestrainingthegrowthofAI(3)Fromstudyontheapparentviscositiesandmicrostructureofpur

7、eA1byadditionofK2TiF6itisshownthatacriticaltimeexistsforapparentviscositiesTheapparentviscositiesincreasesignificantlybeyondthecriticaltimevalueThegrainsarerefinedontheadditionofrefinerloweringtheapparentviscosity(4)Thee

8、ffectofTiontheapparentviscosityofpureA1islimited(5)TheadditionofrefinerscanincreasethecriticalvolumefractionofsolidatwhichtheapparentviscosityincreasesdrasticallyWhellTiBorTi—CrefinerisaddedintoAI—Sialloys，theeffectofref

9、inementisbetterthanthatwhenTiisaddedinaloneItwilllowertheslurryviscosityatthesamefractionofsolidSiaffectstherefiningeffectofTiandB1eadingtothechangeofapparentviscosityKeywords：Semi—solidslurry，AI—Sialloys，refiningmechani