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CollegeofMaterialsScienceandEngineering1FundamentalsofMaterialsScience郭福教授北京工业大学材料科学与工程学院CollegeofMaterialsScienceandEngineering——材料科学基础——CollegeofMaterialsScienceandEngineering2CollegeofMaterialsScienceandEngineeringCollegeofMaterialsScienceandEngineering3CollegeofMaterialsScienceandEngineeringCollegeofMaterialsScienceandEngineering4WarmingUp…Whatisconsideredasaneutecticreaction?Whatisconsideredasaneutectoidreaction?Whatisconsideredasaperitecticreaction?L+共晶反应+共析反应L+包晶反应CollegeofMaterialsScienceandEngineeringFe-Fe3CPHASEDIAGRAM—铁碳相图—CollegeofMaterialsScienceandEngineering6IMPORTANCEOFFe-Fe3CSYSTEMOfallbinaryalloysystems,theonethatispossiblythemostimportantisthatforironandcarbon.Bothsteelsandcastirons,primarystructuralmaterialsineverytechnologicallyadvancedculture,areessentiallyiron-carbonalloys.钢铁是现代机械制造业中应用最为广泛的金属材料。Thefocusofthislectureistostudythephasediagramforthissystemandthedevelopmentofmicrostructures.铁碳系统及其显微组织的演变Therelationshipsbetweenheattreatment,microstructure,andmechanicalpropertiesarebasedonthephasediagramofthissystem.CollegeofMaterialsScienceandEngineering7CollegeofMaterialsScienceandEngineering材料科学基础什么知识最重要?您要找的是不是:铁碳相图CollegeofMaterialsScienceandEngineering铁碳合金相图是研究铁碳合金的基础。它是研究铁碳合金的成分、温度和组织结构之间关系的图形。铁碳合金相图是人类经过长期实践并进行大量科学实验总结出来的。Let’sseehowTalkingTomsaysCollegeofMaterialsScienceandEngineering10Fe-Fe3CPHASEDIAGRAMIntheirsimplestform,steelsarealloysofIron(Fe)andCarbon(C).ACDEFGSPQ1147℃727℃LAL+A4.3%C2.14%C0.0218%C6.69%CFeFe3CLdLd+Fe3CⅠA+Ld+Fe3CⅡFA+FP0.77%CLd’K(P+Fe3C)P+Ld’+Fe3CⅡLd’+Fe3CⅠP+FP+Fe3CⅡ(F+Fe3C)A+Fe3CⅡL+Fe3CⅠ(A+Fe3C)CollegeofMaterialsScienceandEngineering11Fe-Fe3CPHASEDIAGRAMTheFe-CphasediagramisafairlycomplexoneACDEFGSPQ1147℃727℃LAL+A4.3%C2.14%C0.0218%C6.69%CFeFe3CLdLd+Fe3CⅠA+Ld+Fe3CⅡFA+FP0.77%CLd’K(P+Fe3C)P+Ld’+Fe3CⅡLd’+Fe3CⅠP+FP+Fe3CⅡ(F+Fe3C)A+Fe3CⅡL+Fe3CⅠ(A+Fe3C)CollegeofMaterialsScienceandEngineering12Fe-Fe3CPHASEDIAGRAMWewillonlyconsiderthesteelandcastironpartofthediagram,uptoaround7%Carbon.ACDEFGSPQ1147℃727℃LAL+A4.3%C2.14%C0.0218%C6.69%CFeFe3CLdLd+Fe3CⅠA+Ld+Fe3CⅡFA+FP0.77%CLd’K(P+Fe3C)P+Ld’+Fe3CⅡLd’+Fe3CⅠP+FP+Fe3CⅡ(F+Fe3C)A+Fe3CⅡL+Fe3CⅠ(A+Fe3C)CollegeofMaterialsScienceandEngineering13CollegeofMaterialsScienceandEngineeringCollegeofMaterialsScienceandEngineering14CollegeofMaterialsScienceandEngineeringCollegeofMaterialsScienceandEngineering15WHATDOYOUKNOWABOUTIRON?-ferrite铁素体-solidsolutionofCinBCCFe•Stableformofironatroomtemperature.•ThemaximumsolubilityofCis0.022wt%.•TransformstoFCC-austeniteat912oC奥氏体CollegeofMaterialsScienceandEngineering16WHATDOYOUKNOWABOUTIRON?-austenite奥氏体-solidsolutionofCinFCCFe•ThemaximumsolubilityofCis2.14wt%.•TransformstoBCCd-ferriteat1394oC•Isnotstablebelowtheeutectoidtemperature(727oC)unlesscooledrapidlyCollegeofMaterialsScienceandEngineering17WHATDOYOUKNOWABOUTIRON?d-ferrited-铁素体-solidsolutionofCinBCCFe•Thesamestructureas-ferrite•StableonlyathighT,above1394oC•Meltsat1538oCCollegeofMaterialsScienceandEngineering18WHATDOYOUKNOWABOUTIRON?Fe3C-ironcarbideorcementiteThisintermetalliccompoundismetastable,itremainsasacompoundindefinitelyatroomT,butdecomposes(veryslowly,withinseveralyears)into-FeandC(graphite)at650-700oC渗碳体CollegeofMaterialsScienceandEngineering19AFEWCOMMENTSABOUTFe-Fe3CCisaninterstitialimpurityinFe.Itformsasolidsolutionwith,,dphasesofiron.MaximumsolubilityinBCC-ferriteislimited(max.0.022wt%at727oC)-BCChasrelativelysmallinterstitialpositions.MaximumsolubilityinFCCausteniteis2.14wt%at1147oC-FCChaslargerinterstitialpositionsCollegeofMaterialsScienceandEngineering20MECHANICALPROPERTIESCementiteisveryhardandbrittle-canstrengthensteels.Mechanicalpropertiesalsodependonthemicrostructure,thatis,howferriteandcementitearemixed.CollegeofMaterialsScienceandEngineering21MAGNETICPROPERTIES-ferriteismagneticbelow768oC.Austeniteisnon-magnetic.CollegeofMaterialsScienceandEngineering22CollegeofMaterialsScienceandEngineeringCLASSIFICATIONOFFERROUSALLOYS—铁碳合金的分类—CollegeofMaterialsScienceandEngineering23CLASSIFICATIONOFFERROUSALLOYSCommerciallypureiron(C0.02%)Steel(C:0.02~2.14%)CastIron(C:2.14~6.70%)CollegeofMaterialsScienceandEngineering24CLASSIFICATIONOFFERROUSALLOYSEutectoidSteel(C=0.76%)共析钢Commerciallypureiron(C0.02%)Steel(C:0.02~2.14%)CastIron(C:2.14~6.70%)CollegeofMaterialsScienceandEngineering25CLASSIFICATIONOFFERROUSALLOYSCommerciallypureiron(C0.02%)Steel(C:0.02~2.14%)CastIron(C:2.14~6.70%)HypoeutectoidSteel(C0.76%)亚共析钢CollegeofMaterialsScienceandEngineering26CLASSIFICATIONOFFERROUSALLOYSCommerciallypureiron(C0.02%)Steel(C:0.02~2.14%)CastIron(C:2.14~6.70%)HypereutectoidSteel(C0.76%)过共析钢CollegeofMaterialsScienceandEngineering27CLASSIFICATIONOFFERROUSALLOYSCommerciallypureiron(C0.02%)Steel(C:0.02~2.14%)CastIron(C:2.14~6.70%)EutecticCastIron(C=4.3%)共晶白口铸铁CollegeofMaterialsScienceandEngineering28CLASSIFICATIONOFFERROUSALLOYSCommerciallypureiron(C0.02%)Steel(C:0.02~2.14%)CastIron(C:2.14~6.70%)HypoeutecticCastIron(C4.3%)亚共晶白口铸铁CollegeofMaterialsScienceandEngineering29CLASSIFICATIONOFFERROUSALLOYSCommerciallypurei