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《mg-zn-al-(y)合金论文：准晶增强的mg-zn-al-（y）合金组织与力学性能研究》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。
1、Mg-Zn-Al-(Y)合金论文：准晶增强的Mg-Zn-Al-（Y）合金组织与力学性能研究【中文摘要】准晶相具有高硬度和强度且热稳定性良好,与镁基体具有良好的结合界面,能有效改善镁合金的室温和高温力学性能。准晶相还能使镁合金变形后的织构更加随机化,从而降低镁合金中常见的拉压不对称性。本文对铸态和挤压态Mg-Zn-Al-(Y)合金的显微组织和力学性能进行了研究,并通过热压缩模拟试验分析合金在热变形过程中流变应力变化规律,探讨了挤压态Mg-Zn-Al-(Y)合金织构和力学性能不对称性。Mg-Zn-Al-(
2、Y)合金主要由-Mg基体和二十面体准晶相组成,加入0.5at.%Y元素可使准晶相更细小弥散分布,细化晶粒组织。热压缩变形模拟试验发现,准晶可促进ZA84和ZAY8405合金动态再结晶,提高合金的塑性变形能力。热挤压后Mg-Zn-Al-(Y)合金组织进一步细化,准晶相依然存在,且在基体中形成更加弥散分布的细小颗粒。挤压温度为230℃,挤压比为10的条件下,ZA84合金的屈服强度、抗拉强度及延伸率分别为178MPa、300MPa和16.0%,ZAY8405合金服强度、抗拉强度及延伸率分别为178MPa、3
3、21MPa和19.3%。准晶相增强的ZA84和ZAY8405合金挤压后织构明显弱化,合金的屈服强度不对称性也明显低于AZ31,随着合金中织构弱化,晶粒取向更加随机化,从而拉伸和压缩过程中力学性能表现趋于一致。【英文摘要】Quasicrystallinephasecaneffectivelyimprovemechanicalpropertiesofmagnesiumalloysatbothroomtemperatureandelevatedtemperature,duetoitshighhardness
4、andstrengthandstrongcombinationwithMgmatrix.Quasicrysalisalsoeffectivetoweakenextrusiontexturesandyieldstrengthasymmetry.Microstructuresandmechanicalpropertiesofbothas-castandextrudedMg-Zn-Al-(Y)alloyswereinvestigated.Therelationshipbetweenflowstressand
5、strainrateofZA84andZAY8405alloysduringhotcompressiondeformationwasstudied.TexturesandyieldstrengthasymmetryofZA84andZAY8405alloyswerealsodiscussed.Mg-Zn-Al-(Y)alloyscontainedi-phaseasamainstrengtheningphase.The0.5at.%Yadditionwaseffectivefordecreasingth
6、esizeofi-phaseandtheincreasingthehomogeneityofitsdispersedstate.Deformationtwinninganddynamicrecrystalizationduringhotcompressionareeasiertotakeplace,duetothehighsymmetryofquasicrystalanditsdefiniteorientationrelationshipwith-Mgmatrix.Thequasicrystalpha
7、seisdispersedasparticlesinthematrixafterhotextrusionat230℃,withanextrusionratioof10.MechanicalpropertiesofMg-Zn-Al-(Y)alloyswerefurtherimproved.Ultimatetensilestrength,yieldstrengthandelongationofas-extrudedZA84alloywere178MPa、300MPaand16.0%,wichofZAY84
8、05alloywere178MPa、321MPaand19.3%.Quasicrystallinephasedispersedinthematrixduringhot-extrusioncanactivatenon-baslslipandrelativelyrandomtextureswerefoundinas-extrudedZA84andZAY8405alloys.YieldstrengthasymmetryofZA84andZAY8405alloy
