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《半固態(tài)成形鋁合金材料研究》由會(huì)員上傳分享，免費(fèi)在線閱讀，更多相關(guān)內(nèi)容在學(xué)術(shù)論文-天天文庫。
1、y965197=l藝京有色金屬研究總院博士學(xué)位論文論文鼷瓣：半蠢態(tài)袋形銹舍金毒害瓣研究徐駿指導(dǎo)教師：至塑墅!堡特小黼員：——，一靴。瓷盤：撼交墨翔；2005年5月3,0器訖皮49辯日期：2005年6月30日答辯婁盟會(huì)主席t纛蘸夔蘧學(xué)位授予單位：=lE窳宥色金屬研巍鎣院jE家有色畿瘸研究惹端AbstractInvestigationofthealuminiumalloyforsemisolidprocessingSemi—solidmetal(SSM)processing，asanewnear-net·shape
2、technology，hasnotbeenwidelyappliedinindustryuptonow,owingtolackofacost—effectivealloywhichissuitableforsemisolidforming．Forthisreason，inthispaper，thecompositionsrangeinAl—Si—Mgsystemwhichislikelymoresuitableforsemisolidprocessingwereoptimizedandselectedbymea
3、nsofthermodynamiccalculationcombinedwimprincipleofSSM．AdesirablecompositionforSSMprocessinghasbeendeterminedbyexperiments．Ithasbeenshownthattherearetheadvantagesnotonlytosaveresearchperiodsandtoreducecostsbutalsotohavepracticalapplicationvaluebyusingthemetho
4、d．Onthebasisofanalysisoftherelationshipsbetweenthecharacteristicsofsemi-solidprocessingandthermodynamiccalculationforAi—Si—Mgsystem，theselectioncriteriaforsemi—solidaluminiumalloyshavebeenestablished．Theeffectsofsiliconandmagnesiumcontentsonsolidificationran
5、ge，quantitiesandspeciesofprimaryphases，temperaturesensitivityofsolidfraction，temperaturewindowofsemi-solidprocessandpotentialforagehardeninginAI—Si-Mgsystemweresystematicallystudied．FourpromisingalloyshavebeendesignedandselectedintherangeofAI-(4—6)Si一(2-3)Mg
6、．TheeffectsofsiliconandmagnesiumcontentsonSSMprocessinghavebeenstudiedbyful"therexperiments．Itwasfoundthatwitlltheincreasesofsiliconandmagnesiumcontents．theliquidus-solidusintervalandsemisolidprocessingtemperaturewindowdecreased，bringingliegtiveeffectstoSSMp
7、rocess．HoweveritwoulddecreasetemperaturesensitivityoffractionsolidandincreasethecontrollabilityofSSMprocesswhenthemagnesiumcontentincreasedproperly．ItWasalsofoundthattheprimeryMgaSicouldresultinpoormicrostmcturesandmechanicalpropegiesofalloys．ButwhenSi／MgWas
8、morethan3，therewouldbenOM92Siphasetooccur．OnthebasisofanalysisofexperimentsandcomparisionwithA356／357alloys，theA1Si6M92alloywasselectedfromfourpromisingalloysasmoresuitablealloyforSSMprocess．The
