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1、材料物理2（Materialphysics2）Fillinthe.Nouninterpretation1.phonon:energyquantumofindependentharmonicoscillatorinlatticevibration.Wavecharacteristics:thepropagationmediumisnotconnectedwiththemedium.Itisthecrystallatticeoftheyard,ion,etc..Thelatticevibration
2、mode(waveisonthelatticethermalvibrationofatomscanbedescribedassimilartothemechanicalresultsofwavepropagation,thewaveiscalledlatticewave)Griffithcracktheory:Griffiththatmanytinycracksordefectsexistsinactualmaterial,undertheactionofexternalforce,andthe
3、secracksaroundthedefectwillproducestressconcentrationphenomenon,whenthestressreachesacertainlevel,thecrackbegantorupturepropagation.ThisisthefamoustheoryofGriffithmicrocracks.Themechanismofparticlereinforcedmaterialisthatparticlescanpreventdislocatio
4、nmovementinthematrixorabsorbpartoftheenergythroughplasticdeformationofparticles,thusstrengtheningthepurpose.Thereasonofthermalexpansionhysteresisincomplexisthattheexpansioncoefficientvariesgreatlyindifferentdirectionsbetweendifferentphasesorgrains,re
5、sultingingreatinternalstress,resultinginmicrocracks.Thereareseveraltypesofcrackpropagation:fracturetype(themaincauseoflowstressfracture)(ZhangKaihang,Itype),staggertype(slidingtype,IItype),tearingtype(IIItype)Thenatureofthermalbreakdown:amediuminanel
6、ectricfieldthatisheatedduetodielectriclossandmaybechargedfromaheatbalancestateofheatdissipationandheatingwhentheappliedvoltageishighenough.Iftheenergyemittedisgreaterthanthat,thetemperatureofthemediumwillbecomehigherandhigheruntilpermanentdamageoccur
7、s.Thecarriersinconductingmaterials:anysubstance,aslongastheexistenceoffreeparticlecharge,whichcanbeproducedintheelectricfieldtostorethecurrent[carriermetalconductoristhefreeelectron,inorganicmaterials(electronicnegativeelectron,ion(hole)ionsorvoids)a
8、scarrierionconductancesaidasacarrierforionicconductance,theelectronconductancecalledelectronicconductivity]Theformofforceanddeformationofinorganicmaterials;elasticdeformation;plasticdeformation;viscousflow;hightemperaturecreepThefactorscausingphonons
