稀土及鋯、鈣對耐熱鎂合金組織及性能的影響研究.pdf

1、哈爾濱理工大學(xué)碩士學(xué)位論文稀土及鋯、鈣對耐熱鎂合金組織及性能的影響研究姓名：遲大釗申請學(xué)位級別：碩士專業(yè)：材料學(xué)指導(dǎo)教師：吉澤升20040301哈爾濱理工大學(xué)工學(xué)碩士論文ResearchOfReAndZrCaEffectOnMicrostructureAndPropertyOfHeatResistanceMgAlloyAbstractInthispaperunderthecombinedfirepreventprotectionofRJ

2、2andBeMgNdZrZnMgYZrZnandMgAIMMCaalloysweresafelypreparedintheopenair.Bymeansofopticalmicroscopescanelectronmicroscope(SEM)electricalprobeefectsofNdZr丫Caonmicrostructureand250Cmechanicalpropertiesinrespectivealloywerestud

3、ied.Microstructureandelevatedtemperaturerupturesectionofthethreealloyswereanalyzed.Staplesofbest2500Cmechanicalpropertiesofthethreealloyswereascertained.Theresultsareasfollows:InMgNdZrZnalloyNdexistsingrainsandgrainbound

4、ariesinformofMg12Nd.WiththeincreaseoftheadditiveofNdtheelevatedtemperaturetensilestrengthofthealloyisimprovingandthenisnotremarkable.WhenthecontentofNdexceeds2.8%theelevatedtemperatureplasticiselevatedandthenreduced.Zris

5、soliddissolvedinMgandwiththeincreaseoftheadditiveofwhichtheelevatedtemperaturetensilestrengthandplasticityareallelevatedandthenreduced.Underthetemperatureof2500Cthewayinwhichthealloyrupturesismainlyplastic.Thereasonables

6、tapleofthealloyis:Mg(balance)Nd(2.8%)Zr(0.8%)Zn(0.35%).InMgYZrZnalloyYexistsingrainboundariesinformofMg24Y5whichdissolveinMgafterheattreatment.WiththeincreaseofadditiveofYtheelevatedtemperaturetensilestrengthofthealloyis

7、elevatedandtheplasticityofthealloyreduced.Underthetemperatureof2500Cthewayinwhichthealloyrupturesismainlyplasticincludingcertainbritlefracture.Thereasonablestapleofthealloyis:Mg(balance)Y(4.0%)Zr(0.8%)Zn(0.35%).InMgAIMMC

8、aalloyCamainlysoliddissolvesintheblendedphasesofMg17A112andAll1RE3whoseprinciplepartisMg37A112.CertainadditiveofCacanpromotetheheatstabilityofMg17A112andtheelevatedtemperaturetensilestrengthofthealloyofbothcastandheattre