鎂合金高溫變形力學行為和組織演變規(guī)律研究.pdf

1、湖南大學碩士學位論文鎂合金高溫變形力學行為和組織演變規(guī)律研究姓名：欒娜申請學位級別：碩士專業(yè)：材料加工工程指導教師：李落星20080201鎂合會高溫變形力學行為和組織演變規(guī)律研究AbstractMagnesiumalloyshaVeagreatpotentialforwideapplicationsintheautomotiVeindustrybecauseoftheirhighstrength—to—graVityratiosAtpr

2、esent，theVastmajorityofmagnesiumproductsfortheautomotiveapplicationsareinthefonnofdiecastingsWroughtmagnesiuma110yshaVesofarfoundvery1imitedusage，althou曲theyareexpectedtohaVehigherstrengthandductilitythanthecastcounterpa

3、rtsOneofthebarrierstotheapplicationsofwroughtmagnesiumalloysistheirlowworkability，asaresultofhexagonalcrystalstructureTheref6re，itisnecessarytoexplorethehotworkingpotentialofthiskindofmaterialsThepresentstudyaimstoiIⅣest

4、igatemenows仃essbehaViorandmicrostmctureeVolutionofAZ3l鋤dAZ80a110ysInthepresentstudy，hotcompressiontestsofAZ3landAZ80magnesiumalloywereperformedonGleeble3500atstrainratesbetweenO0150s。1andO0390s。Ianddefomationtemperatures

5、between300—500℃，respectiVelyTheinnuenceoftheparametersonthestressstfaincurveswasanalyzedtodeteminetheconstantsintheconstitutiVeequationsThemicrostructuresofmagnesiuma110yduringcompressionwereobserVedbyusingMM一6horizontal

6、opticalmicroscope(OM)ofLeitZCompanyLimitedof、vestGermanandtransitionelectronmicroscope(TEM)ofH一800TheresultsshowedthatasthetemperaturewasincreasedaIldthestrainratewasdecreased，theflowstressdecreasedAthighstrainrates，duet

7、otheincreasingt鋤peratureofthesamplesduringthedefon】艙tionprocess，thetmenowstressshouldbecorrectedCorrectionresultsshowedthatthecorrectednowsnessesweregenerallyhigherthanmeuncorrectedValuesInaddition，meconstalltsofconstitu

8、tiveequationswerealsoobtainedTheinnueIlceoft鋤peratllreandstainrateonthemicrostmctllred謝ngthedeforTIlationprocesswaSdiscussedGenerally，thedef0咖ed筍ainsizeincreaSedwithmeincreasingofdefo肌ationtemperatureandthedecre嬲ingofstr

9、ainrateButat10wtemperatureandahi曲strainrate，thedef0rmedgrainswerecoarserthanthoseatmiddlestrainratesasaresultofthesignificanttemperatureduringthedeformationForAZ80alloy，Twinningwasthedominatedefomationmechanicatmediatedt

10、emperaturesTheprimarygrainswerediVidedbytheintersectiontwinningsThedef：Dmedgrainboundarieswerestraightandthedistributionofgrainsizewasnon_homogeneousDynamicrecrystallizationoccurreddufingthedefomationofthealloyathightemp