alcu体系扩散过程的分子动力学分析word格式论文.docxVIP

扩散结合的影响，仅考虑温度的影响。研究表明：扩散结合过程中主要是铜原子向铝端扩散；扩散层的厚度依赖于温度，温度越高，扩散层越厚；扩散过程中扩散层结构呈现无序化，铜原子以较慢的速率扩散但可以深入铝晶格内部，铝原子以较快的速率扩散但难以进入铜晶格的内部。同时，本文还计算了扩散结合过程中铝和铜的扩散系数及扩散激活能，计算结果表明当温度处在750-800K之间时，铝-铜界面扩散结合的效果最好。最后，对铜原子在铝中的可能的扩散机制进行分析，分析表明，铜原子在铝中的主要扩散机制为第一近邻跃迁机制。关键词：分子动力学EAM势函数扩散铝-铜体系MOLECULARDYNAMICSSIMULATIONSOFDIFFUSIONFORAl-CuSYSTEMABSTRACTDiffusionisadynamicprocedureandplaysasignificantruleinvarious physicalandchemicalreactionprocesses,suchastheoxidationofmetals, sintering,carburizing,homogenizingandformationofsemiconductorPN junction;alloftheseprocessesarecloselyboundupwithdiffusion.Bothof aluminumandcopperarewidelyusedintheelectronicindustry,andthe aluminum-coppercompositestructuresalsohasawidelyapplicationinthefiled ofaerospaceandmicroelectronics.Thestudyofaluminum-copperjointsisthe keypointofachievingavailabilityofaluminum-coppercompositestructures. Thestudyoftheselfdiffusionofaluminum,copperandthediffusionofAl-Cu alloysareveryimportantforjointofAlandCu.Inthispaper,themolecular dynamics(MD)techniquewasemployedtosimulatetheprocessesof self-diffusionofaluminumandcopperandthediffusionbondingofAl/Cu interface incombinewiththeembeddedatomicmethod(EAM) potential.Forbulkdiffusion,molecularsimulationisconfrontedwithacertain difficulty,e.g.atlowtemperatures,theatomicjumpfrequencyistoolowto producethestatisticallysignificantatomicdisplacementwithinashorttimeand beyondtheacceptabletimescaleofthemolecularsimulation.Inthispaper,the methodofexcesspointdefectscreatedinthebulkwasusedtoovercometheshortcomingofMDfordiffusion.Thelinearexpansioncoefficient,vacancy formationandself-diffusionmigrationenergyofAlandCuwerecalculated. Thentheself-diffusionactivationenergywas obtainedbycorrectionofthe equilibriumdefectconcentration.Thesimulatedresultsindicatethatthemethod ofexcesspointdefectsissuitableformoleculardynamicssimulationofbulk diffusion.Fortheinterfacediffusion,theinterfaceresultsintheinterfacialatomswith ahighjumpfrequencyandrapiddiffusion.Themoleculardynamicssimulator, hence,canbestraight