The unclear interfacial characteristics of Ag/Cu interface during diffusion welding limit the improvement of mechanical properties of Ag/Cu bimetallic strips.The growth orientation and evolution of Ag and Cu crystals ...The unclear interfacial characteristics of Ag/Cu interface during diffusion welding limit the improvement of mechanical properties of Ag/Cu bimetallic strips.The growth orientation and evolution of Ag and Cu crystals between Ag and Cu strips were investigated by electron backscatter diffraction(EBSD)analysis,and the interfacial properties of various Ag/Cu interfacial configurations were calculated using first-principles calculations to elucidate the diversified interfacial characteristics.Three interface bonding states,including Ag(100)/Cu(100),Ag(110)/Cu(110)and Ag(111)/Cu(111),were preferentially formed in Ag/Cu bimetallic strips during roll bonding.The intensity of Ag(100)/Cu(100)interface increases with the increasing deformation amounts during cold rolling,accompanied by the decreased intensity of Ag(110)/Cu(110)and Ag(111)/Cu(111)interfaces.The largest adsorption work and lowest interface energy of Ag(100)/Cu(100)interface at the“center”position reveal the transition from Ag(110)/Cu(110)and Ag(111)/Cu(111)interfaces to Ag(100)/Cu(100)interface.展开更多
The atom (Ag,Cu) diffusion behavior and the effect of technology on the interface of rolled Ag/Cu composite contact were investigated. The concentration of Ag and Cu atoms near the interface was determined with electr...The atom (Ag,Cu) diffusion behavior and the effect of technology on the interface of rolled Ag/Cu composite contact were investigated. The concentration of Ag and Cu atoms near the interface was determined with electron probe. The bonding strength of composite interface was tested and the fracture in tensile sample was observed by SEM. The results show that there was inter diffusion of Ag and Cu atoms on the interface, which formed compact layer with high bonding strength of 98 MPa. The practical application proved that the Ag/Cu composite interface is reliable.展开更多
Thermal conduetances between Cu and graphene covered carbon nanotubes （gCNTs） are calculated by molecular dynamics simulations. The results show that the thermal conductance is about ten times larger than that of Cu...Thermal conduetances between Cu and graphene covered carbon nanotubes （gCNTs） are calculated by molecular dynamics simulations. The results show that the thermal conductance is about ten times larger than that of Cu- CNT interface. The enhanced thermal conductance is due to the larger contact area introduced by the graphene layer and the stronger thermal transfer ability of the Cu-gCNT interface. From the linear increasing thermal conductance with the increasing total contact area, an effective contact area of such an interface can be defined.展开更多
The reactive spread behaviour of Cu particles on the surJace of Al has been studied.The role of oxide film and the .formation mechanism of the joint during Al/Cu contacting reaction brazing have been discussed.
The fundamental thermal limitation of pure copper impedes progress in high-power devices,which is becoming more critical with advances in power electronics.The Cu/diamond composite becomes a promising candidate for th...The fundamental thermal limitation of pure copper impedes progress in high-power devices,which is becoming more critical with advances in power electronics.The Cu/diamond composite becomes a promising candidate for thermal management due to its excellent theoretical thermal conductivity and customizable coefficient of thermal expansion(CTE).Actually,the thermal conductivity of Cu/diamond composite is much lower than its theoretical value,for which a key bottleneck is interfacial thermal transport at the Cu/diamond interface.However,many atomic-level microscopic mechanisms of heat transport at Cu/diamond interfaces remain poorly understood at present.Especially when different interlayer materials are involved,theoretical studies become extremely complex and challenging.In this work,a machine learning potential for comprehensive simulations of thermal transport at Cu/diamond interfaces has been successfully constructed.The effects of key factors,such as interlayer material,temperature,strain,and crystal orientation,on heat transport at Cu/diamond interfaces have been studied.Furthermore,the underlying mechanisms are thoroughly analyzed and discussed.Finally,the insightful strategies are proposed to optimize and enhance the thermal properties of Cu/diamond interfaces.These advancements can lay a foundation and pave the way for further investigations into interfacial thermal transport at Cu/diamond interfaces as well as in other structures containing interlayer materials.展开更多
基金supported by the National Natural Science Foundation of China(No.52474401)the Project funded by the China Postdoctoral Science Foundation(No.2022M712919)+1 种基金Open Project of State Key Laboratory of Advanced Brazing Filler Metals and Technology(SKLABFMT-2021-03)Guangdong Basic and Applied Basic Research Foundation(2023A1515140124).
文摘The unclear interfacial characteristics of Ag/Cu interface during diffusion welding limit the improvement of mechanical properties of Ag/Cu bimetallic strips.The growth orientation and evolution of Ag and Cu crystals between Ag and Cu strips were investigated by electron backscatter diffraction(EBSD)analysis,and the interfacial properties of various Ag/Cu interfacial configurations were calculated using first-principles calculations to elucidate the diversified interfacial characteristics.Three interface bonding states,including Ag(100)/Cu(100),Ag(110)/Cu(110)and Ag(111)/Cu(111),were preferentially formed in Ag/Cu bimetallic strips during roll bonding.The intensity of Ag(100)/Cu(100)interface increases with the increasing deformation amounts during cold rolling,accompanied by the decreased intensity of Ag(110)/Cu(110)and Ag(111)/Cu(111)interfaces.The largest adsorption work and lowest interface energy of Ag(100)/Cu(100)interface at the“center”position reveal the transition from Ag(110)/Cu(110)and Ag(111)/Cu(111)interfaces to Ag(100)/Cu(100)interface.
文摘The atom (Ag,Cu) diffusion behavior and the effect of technology on the interface of rolled Ag/Cu composite contact were investigated. The concentration of Ag and Cu atoms near the interface was determined with electron probe. The bonding strength of composite interface was tested and the fracture in tensile sample was observed by SEM. The results show that there was inter diffusion of Ag and Cu atoms on the interface, which formed compact layer with high bonding strength of 98 MPa. The practical application proved that the Ag/Cu composite interface is reliable.
基金Supported by the National National Science Foundation of China under Grant No 61131004the Fundamental Research Funds for the Central Universities under Grant No DUT14LAB11
文摘Thermal conduetances between Cu and graphene covered carbon nanotubes （gCNTs） are calculated by molecular dynamics simulations. The results show that the thermal conductance is about ten times larger than that of Cu- CNT interface. The enhanced thermal conductance is due to the larger contact area introduced by the graphene layer and the stronger thermal transfer ability of the Cu-gCNT interface. From the linear increasing thermal conductance with the increasing total contact area, an effective contact area of such an interface can be defined.
文摘The reactive spread behaviour of Cu particles on the surJace of Al has been studied.The role of oxide film and the .formation mechanism of the joint during Al/Cu contacting reaction brazing have been discussed.
基金funded by the National Natural Science Foundation of China(Grant Nos.92473102,52202045,62004141)the Shenzhen Science and Technology Program(Grant No.JCYJ20240813175906008)the Open Fund of Hubei Key Laboratory of Electronic Manufacturing and Packaging Integration(Wuhan University)(Grant No.EMPI2025007).The numerical calculations in this paper have been done on the supercomputing system in the Supercomputing Center of Wuhan University.
文摘The fundamental thermal limitation of pure copper impedes progress in high-power devices,which is becoming more critical with advances in power electronics.The Cu/diamond composite becomes a promising candidate for thermal management due to its excellent theoretical thermal conductivity and customizable coefficient of thermal expansion(CTE).Actually,the thermal conductivity of Cu/diamond composite is much lower than its theoretical value,for which a key bottleneck is interfacial thermal transport at the Cu/diamond interface.However,many atomic-level microscopic mechanisms of heat transport at Cu/diamond interfaces remain poorly understood at present.Especially when different interlayer materials are involved,theoretical studies become extremely complex and challenging.In this work,a machine learning potential for comprehensive simulations of thermal transport at Cu/diamond interfaces has been successfully constructed.The effects of key factors,such as interlayer material,temperature,strain,and crystal orientation,on heat transport at Cu/diamond interfaces have been studied.Furthermore,the underlying mechanisms are thoroughly analyzed and discussed.Finally,the insightful strategies are proposed to optimize and enhance the thermal properties of Cu/diamond interfaces.These advancements can lay a foundation and pave the way for further investigations into interfacial thermal transport at Cu/diamond interfaces as well as in other structures containing interlayer materials.
