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1、譬塞鎏圣三塵耋三蘭堡圭簍堡篁蘭AZ91D鎂合金半固態(tài)觸變成形工藝研究摘要半固態(tài)金屬成形(SSP)其有近終藏形,成形零件致密、力學(xué)徑能良好、機(jī)械加工量少,模具壽命長,可制造復(fù)雜結(jié)構(gòu)件等獨(dú)特的優(yōu)點(diǎn),愈來愈受到世爨各霪熬重鞔。鎂合眾熔液由于易于氧化燃燒,常規(guī)成形加工困難,質(zhì)黛不易控制。而采用鎂合余半固念成形技術(shù),就可以很好地解決這一難題。本文利用應(yīng)變誘笈熔證激潘法(Strain-InducedMeltActivation,麓稼SlMA)髑餐出了AZ91D鎂合金半圃態(tài)坯料,并對(duì)AZ91D鎂合金半固態(tài)觸變成形時(shí)的翦切流變性縫和滾動(dòng)性錢傲了深入靜試驗(yàn)磷究和理論分李廳。本
2、文利用SIMA法,對(duì)細(xì)化和球化AZ91D鎂合金鑄件晶粒的機(jī)理作了細(xì)致的研究。分析了冷塑性變形率、半固態(tài)等溫溫度和半固態(tài)等溫時(shí)間與半固態(tài)坯料微觀組織的關(guān)系,得出了本試驗(yàn)條件下制備AZ91D鎂合金半固態(tài)坯料的最佳工藝參數(shù):冷塑性變形率7%~9%,半固態(tài)等溫溫度570±5℃,半固態(tài)等溫時(shí)間20min~30min。本文利用自制的模具,對(duì)AZ91D鎂合會(huì)半固態(tài)的剪切流變性能作了初步的研究。分析了570。C時(shí),不同的半固態(tài)等溫時(shí)間對(duì)AZ91D鎂合金半固態(tài)剪切流變性能的影響;得出了本試驗(yàn)條件下,AZ91D鎂合金半固態(tài)剪切流變的最佳工藝參數(shù):570℃,半固態(tài)等溫時(shí)問30mi
3、n。同時(shí)根據(jù)試驗(yàn)所發(fā)生的現(xiàn)象、得出的數(shù)據(jù),建立了AZ91D鎂合金半固態(tài)流變模型:Hl一(Nl/H2)一(N2/S)。而為了了解AZ91D鎂合金半固態(tài)下的觸變流動(dòng)性能,本文利用自制的模具,對(duì)AZ91D鎂合金570℃時(shí)的觸變流動(dòng)性能作了試驗(yàn)研究。分析了不同半固態(tài)等溫時(shí)間對(duì)AZ91D鎂合金半固態(tài)觸變成形時(shí)流動(dòng)性能的影響,揭示了AZ91D鎂臺(tái)金半固態(tài)下觸變流動(dòng)機(jī)理,得出了本試驗(yàn)條件下最佳的工藝參數(shù):570℃時(shí),半固態(tài)等溫時(shí)間為30min~45min。同時(shí)對(duì)AZ91D鎂合金半固態(tài)觸變流動(dòng)成形件作了拉伸試驗(yàn),結(jié)果表明:AZ91D鎂合金半固態(tài)成形件的力學(xué)性能要高于常規(guī)鎂合
4、金成形件的力學(xué)性能。關(guān)鍵詞AZ91D:半固態(tài)成形;SIMA;靜態(tài)剪切;流動(dòng)性能豎!鎏!些!.::耋!耋些!:蘭!蘭墮蘭!THESTUDYOFSEMI—SOLIDTHIX0.PROCESS0FAZ91DMAGNESIUMALLOYSAbstractSemi-solidmetalprocess(ssP)processisanewnearnetshapetechnology.Anditsdripmoldingiscompaction,highmechanicalproperty,littlemachiningandcomplex.So,itismoreandmor
5、etakenintoaccountinallovertheworld.Becausemoltenofmagnesiumalloysareeasytoburn,magnesiumalloysaredifficulttoconventionalprocessandcontrolquality.SinceSSPwasappliedonmagnesiumalloys,ithadsettledthekeypuzzle.ThispaperusedStrain—InducedMeltActivation(SIMA)topreparethesemi—solidblankof
6、AZ91Dmagnesiumalloys,andresearchedtheshear-rheologypropertyandthefluxionpropertyofthixo—processwithAZ91Dmagnesiumalloysbyexperiment.Thispaperresearchedtherefiningandspheroidizationmechanicsofthesemi—solidgrainsofAZ91DmagnesiumalloysbySMA.ttanalyzedtheeffectofcoolplasticdeformationr
7、atio,semi—solidtemperatureandholdingtimeonmicrostructureofsemi.solidblank.Theresultsindicatethat:underthisexperimentcondition,thebestprocessingparametersofthesemi—solidblankpreparationofAZ9tDmagnesiumalloysarecoolplasticdeformationratio7%~9%。semi—solidtemperature570±5℃,holdingtime2
8、0min~30min.Thispaperstudie