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《mgyznzr耐熱鎂合金組織和性能研究》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(kù)。
1、摘要鎂合金是實(shí)際應(yīng)用中最輕的金屬結(jié)構(gòu)材料，在汽車(chē)輕量化方面的作用日益受到人們的重視。但是，目前已有的鎂合金往往室溫力學(xué)性能較差或者高溫抗蠕變性能較差，這限制了它在汽車(chē)工業(yè)中的應(yīng)用。目前已有的MEZ（Mg-2RE-0.35Zn-0.3Zr）合金具有優(yōu)良的高溫抗蠕變性能，但室溫拉伸性能較差，本文通過(guò)用Y元素替代MEZ合金中的混合稀土，并在合金中增添少量的Zn元素，希望在保持合金優(yōu)良的抗蠕變性能的基礎(chǔ)上提高合金的強(qiáng)度。本研究首先研究了重力鑄造條件下Mg-Y-Zn-Zr合金的組織與性能，并在此基礎(chǔ)上采用Mg-Y-Zn-Zr合金成功的實(shí)現(xiàn)了汽車(chē)吸塵器底板的壓鑄試驗(yàn)，并對(duì)壓鑄合金的組織與性能進(jìn)行
2、了系統(tǒng)地研究。對(duì)重力鑄造Mg-Y-Zn-Zr合金的組織與性能進(jìn)行研究發(fā)現(xiàn)，Mg-0.8%Zn-0.35%Zr合金組織為單相α-Mg，在合金中添加Y元素，隨著添加的Y元素含量的增加，合金晶粒得到細(xì)化，晶界離異共晶相的數(shù)目增多，且出現(xiàn)了大量的層片狀關(guān)鍵詞：鎂合金；壓鑄；蠕變性能；釔；強(qiáng)度IAbstractAsthelightestmetalstructurematerial,magnesiumalloysofferhighspecificstrength,specificstiffness,superiordampingcapacity,excellentmachinabiltyandc
3、astability.Demandsfromautomotiveindustryforincreasinglylightweightcomponentshaveresultedinanincreasedinterestinmagnesiumalloy.However，mostdie-castmagnesiumalloyshavepoorstrengthorbadcreepresistantproperty,whichlimittheirapplicationinautomobilepowertraincomponents.ConsideringthatMEZalloy(Mg-2RE-
4、0.35Zn-0.3Zr)isanalloywithexcellentcreeppropertybutlowstrength,cerium-richmischmetalwassubstitutedbyyttriumandzirconiumwasaddedintothealloyinordertoimprovethetensilestrength.Theeffectsofyttriumonthemicrostructureandpropertiesofgravity-castingMg-Y-Zn-Zralloywerestudied,whichwasthebasisoftheresea
5、rchonthemicrostructureandpropertiesofdie-castingMg-Y-Zn-Zralloy.Itindicatedthatwithmoreyttriumaddedtogravity-castingMg-Zn-Zralloy,thegrainwasrefinedandtheamountofthesecondaryphaseonthegrainboundaryincreased,thereforthethensilestrengthatambientandelevatedtemperaturesaswellascreeppropertywereimpr
6、oved.Asresult,when3.5%Ywasadded,thetensilestrengthatroomtemperatureandelevatedtemperatureaswellasthecreepresistantpropertyreachedthepeak.ThenMg-2.64%Y-0.96%Zn-0.35%ZrandMg-4.51%Y-0.99%Zn-0.41%Zralloyswereusedinthedie-castingofautomobilesoleplate,whichwasprovedtobeagreatsuccess.Themicrostructure
7、andpropertyofthetwodie-castingMg-Y-Zn-Zralloywerestudied.Itwasshownthatthegrainwasrefinedandthesecondaryphaseonthegrainboundarymanifoldedinthedie-castingMg-Y-Zn-Zralloy,whichresultedtheimprovementofthethensilestrengthatambientande
