超導(dǎo)強(qiáng)磁場下Bi-Mn包晶合金凝固行為.pdf

1、8219乏2中心分類號：密級：單位代號：11903學(xué)號：02720048F萬萬孿⑨碩士學(xué)位論SHANGHAIUNIVERSITYMASTER’STHESIS作者學(xué)科專業(yè)導(dǎo)師完成日期向石鋼鐵冶金任忠鳴教授二零零五年四月文E海人學(xué)碩士學(xué)位論文AbstractThcsolidificationbehaviorofBi—Mnperitecticalloyinthehighmagneticfieldwasinvestigatedexperimen

2、tallyinthispaperTheeasymagneticaxisturnedtothedirectionofmagneticfieldandaggregatedalongthedirectionofmagneticfieldwhenapplyingthehighmagneticfield；andtheflakephaseseparateswiththehighmagneticf01_ceBasedonthemagnetizatio

3、ntheoryandcrystalgrowththeorythesolidificationbehaviol“ofprimaryphaseMnBiofBi—MnalloywasanalyzedwiththemagneticanisotrophismandthegrowthanisotrophismTheout—seperationofMnBiphaseinthehighmagneticfieldwasinvestigated：whent

4、healloywassolidifiedat4600C，MnBigrainswasdottedinBirandomlyinsmallgobbetshapeanditgatheredtogetherintolargeblockshapewiththetemperaturegettingdown；whenthetemperaturedroppedattheperitecticreactiontemperature，thegrainbecam

5、elooseandseparatedfromblockshapeintoflakeshapeandthec—axisturnedtothedirectionofmagneticfield；fromthex—raydiffraction，itfoundthatMnBigrainorientedalongthedirectionofmagneticfieldTherelationshipbetweenorientationdegreeand

6、magneticintensityorholdingtimeinthemagneticfieldgotfromtheexperimentsThemagnetizationofthemagneticfieldresultsinthechangeoftheinternalenergyinthesystem，whichwillchangethethermodynamicstateofthesystemDuringthesolidificati

7、onofalloytheapplyingofthehighmagneticfieldwithenoughhighintensitywillinfluencethesolidificationtemperatureButuptonOW，ithasnotbeenreportedyetAccordingtotheforceinthegradientmagneticfieldandtherelatedmagnetictheorythephase

8、transformationwasinvestigatedbymeasuretheforceofthealloyinthemagneticfieldHence，thephasetransformationtemperatureillthemagneticfieldwithdifferentintensitywasmeasuredandtheinfluenceofhighnmgneticfieldonthephasetransformat

9、ionwasanalyzedthermodynamicallyItwasfoundthatthephasetransformationtemperatureincreasedwiththeincreaseofmagneticfieldintensity；thephasetransformationtemperatureincreasedby20℃intile1OTmagneticfield：themagnetizationofthehi