材料科学与工程导论双语课件教学课件 作者 陈克正 王玮 刘春延 等编Chapter 4.ppt

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1、INTRODUCTIONTOMATERIALSSCIENCEANDENGINEERINGQingdaoUniversityofScience&TechnologyKezhengChenWeiWangChuntingLiu国家级双语教学示范课程CHAPTER4METALLICMATERIALS4.1MechanicalPropertiesofMetals4.2DislocationsandStrengthening4.3Failure4.4PhaseDiagramsandPhaseTransformationsinMetals4.5ApplicationsandProcessingo

2、fMetalAlloysMechanicalpropertiesElectricalandmagneticpropertiesThermalpropertiesOpticalpropertiesarethewaythematerialrespondstotheenvironmentandexternalforces4123PROPERTIESChemicalstability5PROPERTIESMechanicalproperties——responsetomechanicalforces,strength,etc.Electricalandmagneticproperties—

3、—responsetoelectricalandmagneticfields,conductivity,magnetization,etc.Thermalproperties——relatedtotransmissionofheatandheatcapacity.Opticalproperties——toabsorption,transmissionandscatteringoflight,refractionindex,etc.Chemicalstabilityincontactwiththeenvironment——corrosionresistance.4.1Mechanic

4、alPropertiesHowdometalsrespondtoexternalloads?Howdowedescribe“mechanicalbehavior”?Vocabulary:Stressandstrain,Hooke’slawClassesofbehavior:Elasticvs.plasticdeformationCharacteristicquantities:Stiffness,strength,ductility,toughness,hardnessGoal:Laythegroundworkfordiscussionofstrengtheningmechanis

5、msandmechanicalfailure.4.1.1IntroductionTounderstandanddescribehowmaterialsdeform(elongate,compress,twist)orbreakasafunctionofappliedload,time,temperature,andotherconditions,weneedfirsttodiscussstandardtestmethodsformechanicalpropertiesofmaterials.•Tensilestress,s:•Shearstress,t:Stresshasunits

6、:N/m2orlb/in2ENGINEERINGSTRESS•Tensilestrain:•Lateralstrain:•Shearstrain:Strainisalwaysdimensionless.ENGINEERINGSTRAINNotethatLisnegativewhenthesampleisintension,soLisalsonegative.5•Simpletension:cable•Simpleshear:driveshaftNote:t=M/AcRhere.Skilift(photocourtesyP.M.Anderson)COMMONSTATESOFSTR

7、ESS6•Simplecompression:Note:compressivestructuremember(s<0here).(photocourtesyP.M.Anderson)(photocourtesyP.M.Anderson)OTHERCOMMONSTRESSSTATES(1)7•Bi-axialtension:•Hydrostaticcompression:Pressurizedtanks<0h(photocourtesyP.M.Anderson)(pho