A longstanding challenge in materials science has been the computational modeling of interfaces between materials with different lattice parameters.Traditional approaches using plane-wave basis sets require either int...A longstanding challenge in materials science has been the computational modeling of interfaces between materials with different lattice parameters.Traditional approaches using plane-wave basis sets require either introducing artificial strain through unified lattice parameters or constructing prohibitively large supercells to accommodate the mismatch.These limitations have often deterred researchers from investigating large,mismatched interfaces,creating a gap in the understanding of these important systems.This work introduces an innovative algorithm that adaptively tunes the plane-wave basis sets to match the periodic structure of each material across the interface.By eliminating the need for extensive supercells or compromised lattice parameters,this new method reduces computational costs while retaining reliable results.The ability to efficiently calculate the eigen-energies of such mismatched systems,a crucial step for full density functional theory(DFT)calculations,is demonstrated with two dimensional versions of InAs/Si and SiC/Si interface potentials.展开更多
Effective thermal transport across solid-solid interfaces which is essential in thermal interface materials(TIMs),necessitates both optimal thixotropy and high thermal conductivity.The role of filler surface modificat...Effective thermal transport across solid-solid interfaces which is essential in thermal interface materials(TIMs),necessitates both optimal thixotropy and high thermal conductivity.The role of filler surface modification,a fundamental aspect of TIM fabrication,in the influence of these properties is not fully understood.This study employs the use of a silane coupling agent(SCA)to modify alumina,integrating experimental approaches with molecular dynamics simulations,to elucidate the interface effects on thixotropy and thermal conductivity in polydimethylsiloxane(PDMS)-based TIMs.Our findings reveal that the variations of SCAs modify both interface binding energy and transition layer thickness.The interface binding energy restricts macromolecular segmental relaxation near the interface,hindering desirable thixotropy and bond line thickness.On the contrary,the thickness of the transition layer at the interface positively influences thermal conductivity,facilitating the transport of phonons between the polymer and filler.Consequently,selecting an optimal SCA allows a balance between traditionally conflicting goals of high thermal conductivity and minimal bond line thickness,achieving an impressively low interface thermal resistance of just 2.45-4.29 K·mm^(2)·W^(-1)at275.8 kPa.展开更多
The rapid development of the information era has led to in-creased power consumption,which generates more heat.This requires more efficient thermal management systems,with the most direct ap-proach being the developme...The rapid development of the information era has led to in-creased power consumption,which generates more heat.This requires more efficient thermal management systems,with the most direct ap-proach being the development of su-perior thermal interface materials(TIMs).Mesocarbon microbeads(MCMBs)have several desirable properties for this purpose,includ-ing high thermal conductivity and excellent thermal stability.Although their thermal conductivity(K)may not be exceptional among all carbon materials,their ease of production and low cost make them ideal filler materials for developing a new generation of carbon-based TIMs.We report the fabrication of high-performance TIMs by incorporating MCMBs in a polyimide(PI)framework,producing highly graphitized PI/MCMB(PM)foams and anisotropic polydimethylsiloxane/PM(PDMS/PM)composites with a high thermal conductivity using directional freezing and high-temperature thermal annealing.The resulting materials had a high through-plane(TP)K of 15.926 W·m^(−1)·K^(−1),4.83 times that of conventional thermally conductive silicone pads and 88.5 times higher than that of pure PDMS.The composites had excellent mechanical properties and thermal stability,meeting the de-mands of modern electronic products for integration,multi-functionality,and miniaturization.展开更多
As electronic devices continue to evolve toward higher power densities,faster speeds,and smaller form factors,the demand for high-performance electronic packaging materials has become increasingly critical.These mater...As electronic devices continue to evolve toward higher power densities,faster speeds,and smaller form factors,the demand for high-performance electronic packaging materials has become increasingly critical.These materials serve as the physical and functional interface between semiconductor components and their operating environment,impacting the overall reliability,thermal management,mechanical protection,and electrical performance of modern electronic systems.This study investigates the development,formulation,and performance evaluation of advanced packaging materials,focusing on polymer-based composites,metal and ceramic matrix systems,and nanomaterial-enhanced formulations.A comprehensive analysis of key performance metrics-including thermal conductivity,electrical insulation,mechanical robustness,and environmental resistance-is presented,alongside strategies for material optimization through interface engineering and processing innovations.Furthermore,the study explores cutting-edge integration technologies such as 3D packaging compatibility,low-temperature co-firing,and high-density interconnects.The findings provide critical insights into the structure-property-processing relationships that define the effectiveness of next-generation packaging materials and offer a roadmap for material selection and system integration in high-reliability electronic applications.展开更多
Phase change thermal interface materials(PC-TIMs)have emerged as a promising solution to address the increasing thermal management challenges in electronic devices.This is attributed to their dual mechanisms of latent...Phase change thermal interface materials(PC-TIMs)have emerged as a promising solution to address the increasing thermal management challenges in electronic devices.This is attributed to their dual mechanisms of latent heat absorption and phase change-induced interfacial wettability.This review explores the fundamental principles,material innovations,and diverse applications of PC-TIMs.The heat transfer enhancement mechanisms are first underlined with key factors such as thermal carrier mismatch at the microscale and contact geometry at the macroscale,emphasizing the importance of material selection and design for optimizing thermal performance.Section 2 focuses on corresponding experimental approaches provided,including intrinsic thermal conductivity improvements and interfacial heat transfer optimization.Section 3 discusses common methods such as physical adsorption via porous materials,chain-crosslinked network designs,and core-shell structures,and their effects on leakage prevention,heat transfer enhancement,and application flexibility.Furthermore,the extended applications of PC-TIMs in thermal energy storage are explored in Section 4,suggesting their potential in diverse technological fields.The current challenges in interfacial heat transfer research and the prospect of PC-TIMs are also discussed.The data-driven machine learning technologies will play an increasingly important role in addressing material development and performance prediction.展开更多
In integrated circuit packaging,thermal interface materials(TIMs)must exhibit high thermal conductivity and electrical resistivity to prevent short circuits,enhance reliability,and ensure safety in high-voltage applic...In integrated circuit packaging,thermal interface materials(TIMs)must exhibit high thermal conductivity and electrical resistivity to prevent short circuits,enhance reliability,and ensure safety in high-voltage applications.We proposed the thermal-percolation electrical-resistive TIM incorporating binary fillers of both insulating and metallic nanowires with an orientation in the insulating polymer matrix.High thermal conductivity can be achieved through thermal percolation,while electrical non-conductivity is preserved by carefully controlling the electrical percolation threshold through metallic nanowire orientation.The electrical conductivity of the composite can be further regulated by adjusting the orientation and aspect ratio of the metallic fillers.A thermal conductivity of 10 W·m^(-1)·K^(-1)is achieved,with electrical non-conductive behavior preserved.This approach offers a pathway to realizing“thermal-percolation electrical-resistive”in hybrid TIMs,providing a strategic framework for designing high-performance TIMs.展开更多
Biomass-derived carbon materials are favored for their abundance and sustainability,and ease of preparation and modification.By surface activation and modification they can have a good electrical conductivity,excellen...Biomass-derived carbon materials are favored for their abundance and sustainability,and ease of preparation and modification.By surface activation and modification they can have a good electrical conductivity,excellent catalytic activity,a remarkable adsorption capacity,and different interfacial physicochemical functionalities.Surface-modified biochars have found wide applications in energy storage,environmental remediation,and catalysis.However,achieving precise and controllable modification of their active sites remains a challenge.Recent advances and future prospects for controlling their surface morphology,defect engineering,and surface coating strategies,with particular attention to their means of fabrication,are reviewed.展开更多
The mechanical properties of the SiC fiber-reinforced Mg-Al metal matrix composite materials have been studied on internal microstructure by (scanning electron microscopy) SEM in-situ tensile test. The emergence and p...The mechanical properties of the SiC fiber-reinforced Mg-Al metal matrix composite materials have been studied on internal microstructure by (scanning electron microscopy) SEM in-situ tensile test. The emergence and propagation of the crack, and the fracture behavior in materials have been observed and studied. It is found that in the case of the tensile test, the crack emerged in SiC fiber initially. In the case of the strong cohesion of the fiber-metal interface, the crack propagated in the fiber, meanwhile the fibers in the neighborhood of the cracked fiber began to crack and the Mg-Al metal deformed plastically, and at last the material fractured. Otherwise the toughness of the materials grows in the case of the lower cohesion of the fiber-metal matrix interface.展开更多
Thermal resistance of low-melting-temperature alloy （LMTA） thermal interface materials （TIMs） was measured by laser flash method before and after different stages of heating. The results showed that the thermal pe...Thermal resistance of low-melting-temperature alloy （LMTA） thermal interface materials （TIMs） was measured by laser flash method before and after different stages of heating. The results showed that the thermal performance of the LMTA TIMs was degraded during the heating process. It is suggested that the degradation may mainly be attributed to the interfacial reaction between the Cu and the molten LMTAs. Due to the fast growth rate of intermetallic compound （IMC） at the solid-liquid interface, a thick brittle IMC is layer formed at the interface, which makes cracks easy to initiate and expand. Otherwise, the losses of indium and tin contents in the LMTA during the interfacial reaction will make the melting point of the TIM layer increase, and so, the TIM layer will not melt at the operating temperature.展开更多
Thermal interface materials(TIMs)play a vital role in the thermal management of electronic devices and can significantly reduce thermal contact resistance(TCR).The TCR between the solid–liquid contact surface is much...Thermal interface materials(TIMs)play a vital role in the thermal management of electronic devices and can significantly reduce thermal contact resistance(TCR).The TCR between the solid–liquid contact surface is much smaller than that of the solid–solid contact surface,but conventional solid–liquid phase change materials are likely to cause serious leakage.Therefore,this work has prepared a new formstable phase change thermal interface material.Through the melt blending of paraffin wax(PW)and low-density polyethylene(LDPE),the stability is improved and it has an excellent coating effect on PW.The addition of aluminum(Al)powder improves the low thermal conductivity of PW/LDPE,and the addition of 15wt%Al powder improves the thermal conductivity of the internal structure of the matrix by 67%.In addition,the influence of the addition of Al powder on the internal structure,thermal properties,and phase change behavior of the PW/LDPE matrix was systematically studied.The results confirmed that the addition of Al powder improved the thermal conductivity of the material without a significant impact on other properties,and the thermal conductivity increased with the increase of Al addition.Therefore,morphologically stable PW/LDPE/Al is an important development direction for TIMs.展开更多
Interface engineering is proved to be the most important strategy to push the device performance of the perovskite solar cell(PSC) to its limit, and numerous works have been conducted to screen efficient materials. He...Interface engineering is proved to be the most important strategy to push the device performance of the perovskite solar cell(PSC) to its limit, and numerous works have been conducted to screen efficient materials. Here, on the basis of the previous studies, we employ machine learning to map the relationship between the interface material and the device performance, leading to intelligently screening interface materials towards minimizing voltage losses in p-i-n type PSCs. To enhance the explainability of the machine learning models, molecular descriptors are used to represent the materials. Furthermore,experimental analysis with different characterization methods and device simulation based on the drift-diffusion physical model are conducted to get physical insights and validate the machine learning models. Accordingly, 3-thiophene ethylamine hydrochloride(Th EACl) is screened as an example, which enables remarkable improvements in VOCand PCE of the PSCs. Our work reveals the critical role of datadriven analysis in the high throughput screening of interface materials, which will significantly accelerate the exploration of new materials for high-efficiency PSCs.展开更多
Thermal contact resistance plays a very important role in heat transfer efficiency and thermomechanical coupling response between two materials,and a common method to reduce the thermal contact resistance is to fill a...Thermal contact resistance plays a very important role in heat transfer efficiency and thermomechanical coupling response between two materials,and a common method to reduce the thermal contact resistance is to fill a soft interface material between these two materials.A testing system of high temperature thermal contact resistance based on INSTRON 8874 is established in the present paper,which can achieve 600 C at the interface.Based on this system,the thermal contact resistance between superalloy GH600 material and three-dimensional braid C/C composite material is experimentally investigated,under different interface pressures,interface roughnesses and temperatures,respectively.At the same time,the mechanism of reducing the thermal contact resistance with carbon fiber sheet as interface material is experimentally investigated.Results show that the present testing system is feasible in the experimental research of high temperature thermal contact resistance.展开更多
Developing advanced thermal interface materials(TIMs)to bridge heat-generating chip and heat sink for constructing an efficient heat transfer interface is the key technology to solve the thermal management issue of hi...Developing advanced thermal interface materials(TIMs)to bridge heat-generating chip and heat sink for constructing an efficient heat transfer interface is the key technology to solve the thermal management issue of high-power semiconductor devices.Based on the ultra-high basal-plane thermal conductivity,graphene is an ideal candidate for preparing high-performance TIMs,preferably to form a vertically aligned structure so that the basal-plane of graphene is consistent with the heat transfer direction of TIM.However,the actual interfacial heat transfer efficiency of currently reported vertically aligned graphene TIMs is far from satisfactory.In addition to the fact that the thermal conductivity of the vertically aligned TIMs can be further improved,another critical factor is the limited actual contact area leading to relatively high contact thermal resistance(20-30 K mm^(2) W^(−1))of the“solid-solid”mating interface formed by the vertical graphene and the rough chip/heat sink.To solve this common problem faced by vertically aligned graphene,in this work,we combined mechanical orientation and surface modification strategy to construct a three-tiered TIM composed of mainly vertically aligned graphene in the middle and micrometer-thick liquid metal as a cap layer on upper and lower surfaces.Based on rational graphene orientation regulation in the middle tier,the resultant graphene-based TIM exhibited an ultra-high thermal conductivity of 176 W m^(−1) K^(−1).Additionally,we demonstrated that the liquid metal cap layer in contact with the chip/heat sink forms a“liquid-solid”mating interface,significantly increasing the effective heat transfer area and giving a low contact thermal con-ductivity of 4-6 K mm^(2) W^(−1) under packaging conditions.This finding provides valuable guidance for the design of high-performance TIMs based on two-dimensional materials and improves the possibility of their practical application in electronic thermal management.展开更多
The barrel lifes of three small caliber rifles were tested by using the propellant with nanomaterial and the standard propellant respectively. The test results show that the service life increases observably due to ad...The barrel lifes of three small caliber rifles were tested by using the propellant with nanomaterial and the standard propellant respectively. The test results show that the service life increases observably due to adding nanomaterial to the propellant. Then, the influence of the nanomaterial on the tube was researched by splitting the two barrels tested and detecting their inner surfaces. It was found that the erosion of the barrel bore is reduced observably by using the propellant with nanomaterial. And it makes the volume and the size of the gun chamber change less. Therefore, the barrel life can be prolonged by adding the nanomaterial in the propellant.展开更多
The forms and structures of the phases in Fe-Ni-Co-Nb-Ti-Si low expansion superal-loys have been studied using analytical electron microscopy, high resolution electron microscopy, chemical phase analysis, X-ray diffra...The forms and structures of the phases in Fe-Ni-Co-Nb-Ti-Si low expansion superal-loys have been studied using analytical electron microscopy, high resolution electron microscopy, chemical phase analysis, X-ray diffraction, etc. The effects of yttrium on the microstructures and properties in the superalloys have also been investigated. The results reveal that trace yttrium mainly located in the platelet precipitates makes the crystal structure changed. The platelet precipitates become smaller, denser and rather homogeneous with appropriate yttrium addition. Compared with the conventional low expansion superalloy, the misfit of the platelet phase with the matrix in the yttrium-containing low expansion superalloy decreases from 0.7% to 0.07%, which indicates very low stress at the interface.展开更多
The growing concern about thermal conductivityand electromagnetic shielding inelectronic equipment has promoted the development of interfacial film materials.In this work,polyvinylidene fluoride(PVDF)/graphene composi...The growing concern about thermal conductivityand electromagnetic shielding inelectronic equipment has promoted the development of interfacial film materials.In this work,polyvinylidene fluoride(PVDF)/graphene composite films with different graphene contents were fabricated by high-energy ball milling,cold isostatic pressing,scraping and coating,successively.High-energy ball milling is beneficial to the dispersion of graphene powder,while cold isostatic pressing can greatly enhance thermal conductivity and mechanical strength by reducing the voids in the film and increasing the contact area of graphene sheets.The thermal conductivity,tensile strength and electromagnetic shielding properties of the films were carefully investigated and compared.It was demonstrated that the thermal conductivity increased from 0.19 W·m^(-1).K^(-1) for pure PVDF to 103.9 W·m^(-1).K^(-1)for the composite film with PVDF:graphene=1:3.Meanwhile the electromagnetic shielding efficiency can reach 36.55 dB.The prepared PVDF/graphene composite films exhibit outstanding overall performance and have the potential for practical applications.展开更多
The atomic level structures of fcc/bcc interfaces in an Fe-9Ni alloy have been examined by means of HREM. It has been found that the orientation of γ prime /α interface had great effects on its atomic structure. T...The atomic level structures of fcc/bcc interfaces in an Fe-9Ni alloy have been examined by means of HREM. It has been found that the orientation of γ prime /α interface had great effects on its atomic structure. These interfaces with different orientations may be composed of only structural ledges, structural ledges with misfit dislocations, superledges with misfit dislocations or only misfit dislocations. A structural model of growth ledge was suggested. The terrace of growth ledge was composed of structural ledges or misfit dislocations. The atomic structure of the riser of growth ledge was the same as that of the side facet of γ prime lath, which is composed of superledges with misfit dislocations.展开更多
The influence of air-cooled blast furnace slag aggregates as replacement of natural aggregates on the water absorption of concrete and mortar was studied, and the mechanism was analyzed. The interface between aggregat...The influence of air-cooled blast furnace slag aggregates as replacement of natural aggregates on the water absorption of concrete and mortar was studied, and the mechanism was analyzed. The interface between aggregate and matrix in concrete was analyzed by using a micro-hardness tester, a laser confocal microscope and a scanning electron microscope with backscattered electron image mode. The pore structure of mortar matrixes under different curing conditions was investigated by mercury intrusion porosimetry. The results showed that when natural aggregates were replaced with air-cooled blast furnace slag aggregates in mortar or concrete, the content of the capillary pore in the mortar matrix was reduced and the interfacial structure between aggregate and matrix was improved, resulting in the lower water absorption of mortar or concrete. Compared to the concrete made with crushed limestone and natural river sand, the initial absorption coefficient, the secondary absorption coefficient and the water absorption capacity through the surface for 7 d of the concrete made from crushed air-cooled blast furnace slag and air-cooled blast furnace slag sand were reduced by 48.9%, 52.8%, and 46.5%, respectively.展开更多
Heat transport is a key energetic process in materials and devices. The reduced sample size, low dimension of the problem and the rich spectrum of material imperfections introduce fruitful phenomena at nanoscale. In t...Heat transport is a key energetic process in materials and devices. The reduced sample size, low dimension of the problem and the rich spectrum of material imperfections introduce fruitful phenomena at nanoscale. In this review, we summarize recent progresses in the understanding of heat transport process in low-dimensional materials, with focus on the roles of defects, disorder, interfaces, and the quantum- mechanical effect. New physics uncovered from computational simulations, experimental studies, and predictable models will be reviewed, followed by a perspective on open challenges.展开更多
基金support of The Boeing Company,as part of the Boeing-Technion Sustainable Aviation Fuel Innovation CenterWe sincerely thank Boeing for their valuable support and collaboration.This project was also conducted within the framework of the Guy Sella Memorial Project at Technion,established by SolarEdge Technologies LTD.Partial funding from The Israeli Sustainable Aviation Fuel Knowledge Center–iSAF,supported by The Israeli Ministry of Innovation,Science,and Technology,is gratefully acknowledgedThis article is based upon work from COST IG18234(NanoCatML),supported by COST(European Cooperation in Science and Technology)http://www.cost.eu.
文摘A longstanding challenge in materials science has been the computational modeling of interfaces between materials with different lattice parameters.Traditional approaches using plane-wave basis sets require either introducing artificial strain through unified lattice parameters or constructing prohibitively large supercells to accommodate the mismatch.These limitations have often deterred researchers from investigating large,mismatched interfaces,creating a gap in the understanding of these important systems.This work introduces an innovative algorithm that adaptively tunes the plane-wave basis sets to match the periodic structure of each material across the interface.By eliminating the need for extensive supercells or compromised lattice parameters,this new method reduces computational costs while retaining reliable results.The ability to efficiently calculate the eigen-energies of such mismatched systems,a crucial step for full density functional theory(DFT)calculations,is demonstrated with two dimensional versions of InAs/Si and SiC/Si interface potentials.
基金financially supported by the National Natural Science Foundation of China(Nos.52373042 and 52103091)the National Key Research and Development Project of China(No.2022YFB3806900)the International Visiting Program for Excellent Young Scholars of SCU。
文摘Effective thermal transport across solid-solid interfaces which is essential in thermal interface materials(TIMs),necessitates both optimal thixotropy and high thermal conductivity.The role of filler surface modification,a fundamental aspect of TIM fabrication,in the influence of these properties is not fully understood.This study employs the use of a silane coupling agent(SCA)to modify alumina,integrating experimental approaches with molecular dynamics simulations,to elucidate the interface effects on thixotropy and thermal conductivity in polydimethylsiloxane(PDMS)-based TIMs.Our findings reveal that the variations of SCAs modify both interface binding energy and transition layer thickness.The interface binding energy restricts macromolecular segmental relaxation near the interface,hindering desirable thixotropy and bond line thickness.On the contrary,the thickness of the transition layer at the interface positively influences thermal conductivity,facilitating the transport of phonons between the polymer and filler.Consequently,selecting an optimal SCA allows a balance between traditionally conflicting goals of high thermal conductivity and minimal bond line thickness,achieving an impressively low interface thermal resistance of just 2.45-4.29 K·mm^(2)·W^(-1)at275.8 kPa.
文摘The rapid development of the information era has led to in-creased power consumption,which generates more heat.This requires more efficient thermal management systems,with the most direct ap-proach being the development of su-perior thermal interface materials(TIMs).Mesocarbon microbeads(MCMBs)have several desirable properties for this purpose,includ-ing high thermal conductivity and excellent thermal stability.Although their thermal conductivity(K)may not be exceptional among all carbon materials,their ease of production and low cost make them ideal filler materials for developing a new generation of carbon-based TIMs.We report the fabrication of high-performance TIMs by incorporating MCMBs in a polyimide(PI)framework,producing highly graphitized PI/MCMB(PM)foams and anisotropic polydimethylsiloxane/PM(PDMS/PM)composites with a high thermal conductivity using directional freezing and high-temperature thermal annealing.The resulting materials had a high through-plane(TP)K of 15.926 W·m^(−1)·K^(−1),4.83 times that of conventional thermally conductive silicone pads and 88.5 times higher than that of pure PDMS.The composites had excellent mechanical properties and thermal stability,meeting the de-mands of modern electronic products for integration,multi-functionality,and miniaturization.
文摘As electronic devices continue to evolve toward higher power densities,faster speeds,and smaller form factors,the demand for high-performance electronic packaging materials has become increasingly critical.These materials serve as the physical and functional interface between semiconductor components and their operating environment,impacting the overall reliability,thermal management,mechanical protection,and electrical performance of modern electronic systems.This study investigates the development,formulation,and performance evaluation of advanced packaging materials,focusing on polymer-based composites,metal and ceramic matrix systems,and nanomaterial-enhanced formulations.A comprehensive analysis of key performance metrics-including thermal conductivity,electrical insulation,mechanical robustness,and environmental resistance-is presented,alongside strategies for material optimization through interface engineering and processing innovations.Furthermore,the study explores cutting-edge integration technologies such as 3D packaging compatibility,low-temperature co-firing,and high-density interconnects.The findings provide critical insights into the structure-property-processing relationships that define the effectiveness of next-generation packaging materials and offer a roadmap for material selection and system integration in high-reliability electronic applications.
基金funding from the National Natural Science Foundation of China(Grant Nos.52306214,52425601,and 52276074)the Shanghai Chenguang Plan Program(Grant No.22CGA78)the National Key Research and the Development Program of China(Grant No.2023YFB4404104)。
文摘Phase change thermal interface materials(PC-TIMs)have emerged as a promising solution to address the increasing thermal management challenges in electronic devices.This is attributed to their dual mechanisms of latent heat absorption and phase change-induced interfacial wettability.This review explores the fundamental principles,material innovations,and diverse applications of PC-TIMs.The heat transfer enhancement mechanisms are first underlined with key factors such as thermal carrier mismatch at the microscale and contact geometry at the macroscale,emphasizing the importance of material selection and design for optimizing thermal performance.Section 2 focuses on corresponding experimental approaches provided,including intrinsic thermal conductivity improvements and interfacial heat transfer optimization.Section 3 discusses common methods such as physical adsorption via porous materials,chain-crosslinked network designs,and core-shell structures,and their effects on leakage prevention,heat transfer enhancement,and application flexibility.Furthermore,the extended applications of PC-TIMs in thermal energy storage are explored in Section 4,suggesting their potential in diverse technological fields.The current challenges in interfacial heat transfer research and the prospect of PC-TIMs are also discussed.The data-driven machine learning technologies will play an increasingly important role in addressing material development and performance prediction.
基金supported by the National Key R&D Program(Grant No.2022YFA1203-100)sponsorship by Shanghai Sailing Program(Grant No.24YF2713800)+2 种基金financial support from the Local College Capacity Building Project of Shanghai Municipal Science and Technology Commission(Grant No.20010500700)the Natural Science Foundation of Shanghai(Grant No.23ZR1424300)Shanghai Shuguang Program(Grant No.22SG56)。
文摘In integrated circuit packaging,thermal interface materials(TIMs)must exhibit high thermal conductivity and electrical resistivity to prevent short circuits,enhance reliability,and ensure safety in high-voltage applications.We proposed the thermal-percolation electrical-resistive TIM incorporating binary fillers of both insulating and metallic nanowires with an orientation in the insulating polymer matrix.High thermal conductivity can be achieved through thermal percolation,while electrical non-conductivity is preserved by carefully controlling the electrical percolation threshold through metallic nanowire orientation.The electrical conductivity of the composite can be further regulated by adjusting the orientation and aspect ratio of the metallic fillers.A thermal conductivity of 10 W·m^(-1)·K^(-1)is achieved,with electrical non-conductive behavior preserved.This approach offers a pathway to realizing“thermal-percolation electrical-resistive”in hybrid TIMs,providing a strategic framework for designing high-performance TIMs.
文摘Biomass-derived carbon materials are favored for their abundance and sustainability,and ease of preparation and modification.By surface activation and modification they can have a good electrical conductivity,excellent catalytic activity,a remarkable adsorption capacity,and different interfacial physicochemical functionalities.Surface-modified biochars have found wide applications in energy storage,environmental remediation,and catalysis.However,achieving precise and controllable modification of their active sites remains a challenge.Recent advances and future prospects for controlling their surface morphology,defect engineering,and surface coating strategies,with particular attention to their means of fabrication,are reviewed.
文摘The mechanical properties of the SiC fiber-reinforced Mg-Al metal matrix composite materials have been studied on internal microstructure by (scanning electron microscopy) SEM in-situ tensile test. The emergence and propagation of the crack, and the fracture behavior in materials have been observed and studied. It is found that in the case of the tensile test, the crack emerged in SiC fiber initially. In the case of the strong cohesion of the fiber-metal interface, the crack propagated in the fiber, meanwhile the fibers in the neighborhood of the cracked fiber began to crack and the Mg-Al metal deformed plastically, and at last the material fractured. Otherwise the toughness of the materials grows in the case of the lower cohesion of the fiber-metal matrix interface.
基金supported by the National Basic Research Program of China (No.2010CB631006)the National Natural Science Foundation of China (No.51171191)
文摘Thermal resistance of low-melting-temperature alloy （LMTA） thermal interface materials （TIMs） was measured by laser flash method before and after different stages of heating. The results showed that the thermal performance of the LMTA TIMs was degraded during the heating process. It is suggested that the degradation may mainly be attributed to the interfacial reaction between the Cu and the molten LMTAs. Due to the fast growth rate of intermetallic compound （IMC） at the solid-liquid interface, a thick brittle IMC is layer formed at the interface, which makes cracks easy to initiate and expand. Otherwise, the losses of indium and tin contents in the LMTA during the interfacial reaction will make the melting point of the TIM layer increase, and so, the TIM layer will not melt at the operating temperature.
基金supported by the National Natural Science Foundation of China,China(No.51874047)the Key Science and Technology Project of Changsha City,China(No.kq2102005)+1 种基金the Special Fund for the Construction of Innovative Province in Hunan Province,China(No.2020RC3038)the Changsha City Fund for Distinguished and Innovative Young Scholars,China(No.kq1802007)。
文摘Thermal interface materials(TIMs)play a vital role in the thermal management of electronic devices and can significantly reduce thermal contact resistance(TCR).The TCR between the solid–liquid contact surface is much smaller than that of the solid–solid contact surface,but conventional solid–liquid phase change materials are likely to cause serious leakage.Therefore,this work has prepared a new formstable phase change thermal interface material.Through the melt blending of paraffin wax(PW)and low-density polyethylene(LDPE),the stability is improved and it has an excellent coating effect on PW.The addition of aluminum(Al)powder improves the low thermal conductivity of PW/LDPE,and the addition of 15wt%Al powder improves the thermal conductivity of the internal structure of the matrix by 67%.In addition,the influence of the addition of Al powder on the internal structure,thermal properties,and phase change behavior of the PW/LDPE matrix was systematically studied.The results confirmed that the addition of Al powder improved the thermal conductivity of the material without a significant impact on other properties,and the thermal conductivity increased with the increase of Al addition.Therefore,morphologically stable PW/LDPE/Al is an important development direction for TIMs.
基金supported by the National Natural Science Foundation of China (62075006)the National Key R&D Program of China (2018YFB1500200)。
文摘Interface engineering is proved to be the most important strategy to push the device performance of the perovskite solar cell(PSC) to its limit, and numerous works have been conducted to screen efficient materials. Here, on the basis of the previous studies, we employ machine learning to map the relationship between the interface material and the device performance, leading to intelligently screening interface materials towards minimizing voltage losses in p-i-n type PSCs. To enhance the explainability of the machine learning models, molecular descriptors are used to represent the materials. Furthermore,experimental analysis with different characterization methods and device simulation based on the drift-diffusion physical model are conducted to get physical insights and validate the machine learning models. Accordingly, 3-thiophene ethylamine hydrochloride(Th EACl) is screened as an example, which enables remarkable improvements in VOCand PCE of the PSCs. Our work reveals the critical role of datadriven analysis in the high throughput screening of interface materials, which will significantly accelerate the exploration of new materials for high-efficiency PSCs.
基金supported by the Fundamental Research Funds for the Central Universities(FRF-BR-10-007A and FRF-AS-09-001A)the National Natural Science Foundation of China(10872104)
文摘Thermal contact resistance plays a very important role in heat transfer efficiency and thermomechanical coupling response between two materials,and a common method to reduce the thermal contact resistance is to fill a soft interface material between these two materials.A testing system of high temperature thermal contact resistance based on INSTRON 8874 is established in the present paper,which can achieve 600 C at the interface.Based on this system,the thermal contact resistance between superalloy GH600 material and three-dimensional braid C/C composite material is experimentally investigated,under different interface pressures,interface roughnesses and temperatures,respectively.At the same time,the mechanism of reducing the thermal contact resistance with carbon fiber sheet as interface material is experimentally investigated.Results show that the present testing system is feasible in the experimental research of high temperature thermal contact resistance.
基金flnancial support by the National Natural Science Foundation of China (52102055, 5227020331, 52075527)National Key R&D Program of China (2017YFB0406000 and 2017YFE0128600)+8 种基金the Project of the Chinese Academy of Sciences (XDC07030100, XDA22020602, ZDKYYQ20200001 and ZDRW-CN-2019-3)CAS Youth Innovation Promotion Association (2020301)Science and Technology Major Project of Ningbo (2021Z120, 2021Z115, 2022Z084, 2018B10046 and 2016S1002)the Natural Science Foundation of Ningbo (2017A610010)Foundation of State Key Laboratory of Solid lubrication (LSL-1912)China Postdoctoral Science Foundation (2020M681965, 2022M713243)National Key Laboratory of Science and Technology on Advanced Composites in Special Environments (6142905192806)K.C. Wong Education Foundation (GJTD-2019-13)the 3315 Program of Ningbo for financial support
文摘Developing advanced thermal interface materials(TIMs)to bridge heat-generating chip and heat sink for constructing an efficient heat transfer interface is the key technology to solve the thermal management issue of high-power semiconductor devices.Based on the ultra-high basal-plane thermal conductivity,graphene is an ideal candidate for preparing high-performance TIMs,preferably to form a vertically aligned structure so that the basal-plane of graphene is consistent with the heat transfer direction of TIM.However,the actual interfacial heat transfer efficiency of currently reported vertically aligned graphene TIMs is far from satisfactory.In addition to the fact that the thermal conductivity of the vertically aligned TIMs can be further improved,another critical factor is the limited actual contact area leading to relatively high contact thermal resistance(20-30 K mm^(2) W^(−1))of the“solid-solid”mating interface formed by the vertical graphene and the rough chip/heat sink.To solve this common problem faced by vertically aligned graphene,in this work,we combined mechanical orientation and surface modification strategy to construct a three-tiered TIM composed of mainly vertically aligned graphene in the middle and micrometer-thick liquid metal as a cap layer on upper and lower surfaces.Based on rational graphene orientation regulation in the middle tier,the resultant graphene-based TIM exhibited an ultra-high thermal conductivity of 176 W m^(−1) K^(−1).Additionally,we demonstrated that the liquid metal cap layer in contact with the chip/heat sink forms a“liquid-solid”mating interface,significantly increasing the effective heat transfer area and giving a low contact thermal con-ductivity of 4-6 K mm^(2) W^(−1) under packaging conditions.This finding provides valuable guidance for the design of high-performance TIMs based on two-dimensional materials and improves the possibility of their practical application in electronic thermal management.
文摘The barrel lifes of three small caliber rifles were tested by using the propellant with nanomaterial and the standard propellant respectively. The test results show that the service life increases observably due to adding nanomaterial to the propellant. Then, the influence of the nanomaterial on the tube was researched by splitting the two barrels tested and detecting their inner surfaces. It was found that the erosion of the barrel bore is reduced observably by using the propellant with nanomaterial. And it makes the volume and the size of the gun chamber change less. Therefore, the barrel life can be prolonged by adding the nanomaterial in the propellant.
基金Chinese foundation of aeronautical science( N o.96 G2 10 0 3)
文摘The forms and structures of the phases in Fe-Ni-Co-Nb-Ti-Si low expansion superal-loys have been studied using analytical electron microscopy, high resolution electron microscopy, chemical phase analysis, X-ray diffraction, etc. The effects of yttrium on the microstructures and properties in the superalloys have also been investigated. The results reveal that trace yttrium mainly located in the platelet precipitates makes the crystal structure changed. The platelet precipitates become smaller, denser and rather homogeneous with appropriate yttrium addition. Compared with the conventional low expansion superalloy, the misfit of the platelet phase with the matrix in the yttrium-containing low expansion superalloy decreases from 0.7% to 0.07%, which indicates very low stress at the interface.
基金This work was supported by the National Natural ScienceFoundationofChina(No.U22B2066,No.12064044)the Major Science and Technology Projects of Anhui Province(No.202103a05020016)+1 种基金the open competition project to select the best candidates to undertake major science and key research projectsofTonglingcity,AnhuiProvince(No.202101JB002)A proportion of this work was supported by the High Magnetic Field Laboratory of Anhui Province and Academician workstation of Hangzhou Xingyu Carbon Environmental Tech Co.,Ltd.,and the Hefei Institutes of Physical Science Director's Fund(No.YZJJ-GGZX-2022-01).
文摘The growing concern about thermal conductivityand electromagnetic shielding inelectronic equipment has promoted the development of interfacial film materials.In this work,polyvinylidene fluoride(PVDF)/graphene composite films with different graphene contents were fabricated by high-energy ball milling,cold isostatic pressing,scraping and coating,successively.High-energy ball milling is beneficial to the dispersion of graphene powder,while cold isostatic pressing can greatly enhance thermal conductivity and mechanical strength by reducing the voids in the film and increasing the contact area of graphene sheets.The thermal conductivity,tensile strength and electromagnetic shielding properties of the films were carefully investigated and compared.It was demonstrated that the thermal conductivity increased from 0.19 W·m^(-1).K^(-1) for pure PVDF to 103.9 W·m^(-1).K^(-1)for the composite film with PVDF:graphene=1:3.Meanwhile the electromagnetic shielding efficiency can reach 36.55 dB.The prepared PVDF/graphene composite films exhibit outstanding overall performance and have the potential for practical applications.
文摘The atomic level structures of fcc/bcc interfaces in an Fe-9Ni alloy have been examined by means of HREM. It has been found that the orientation of γ prime /α interface had great effects on its atomic structure. These interfaces with different orientations may be composed of only structural ledges, structural ledges with misfit dislocations, superledges with misfit dislocations or only misfit dislocations. A structural model of growth ledge was suggested. The terrace of growth ledge was composed of structural ledges or misfit dislocations. The atomic structure of the riser of growth ledge was the same as that of the side facet of γ prime lath, which is composed of superledges with misfit dislocations.
基金Funded by the National Natural Science Foundation of China(Nos.51778003 and 51308004)the Project of Anhui Provincial Education Department for Sending Visiting Scholars to Research Abroad(No.gxfx ZD2016134)+1 种基金the Anhui Province Higher Education Revitalization Program Talent Project([2014]No.11)the National Key Research and Development Plan(No.2017YFB0310001)
文摘The influence of air-cooled blast furnace slag aggregates as replacement of natural aggregates on the water absorption of concrete and mortar was studied, and the mechanism was analyzed. The interface between aggregate and matrix in concrete was analyzed by using a micro-hardness tester, a laser confocal microscope and a scanning electron microscope with backscattered electron image mode. The pore structure of mortar matrixes under different curing conditions was investigated by mercury intrusion porosimetry. The results showed that when natural aggregates were replaced with air-cooled blast furnace slag aggregates in mortar or concrete, the content of the capillary pore in the mortar matrix was reduced and the interfacial structure between aggregate and matrix was improved, resulting in the lower water absorption of mortar or concrete. Compared to the concrete made with crushed limestone and natural river sand, the initial absorption coefficient, the secondary absorption coefficient and the water absorption capacity through the surface for 7 d of the concrete made from crushed air-cooled blast furnace slag and air-cooled blast furnace slag sand were reduced by 48.9%, 52.8%, and 46.5%, respectively.
基金supported by the National Natural Science Foundation of China(11222217)the State Key Laboratory of Mechanics and Control of Mechanical Structures,Nanjing University of Aeronautics and Astronautics(MCMS-0414G01)
文摘Heat transport is a key energetic process in materials and devices. The reduced sample size, low dimension of the problem and the rich spectrum of material imperfections introduce fruitful phenomena at nanoscale. In this review, we summarize recent progresses in the understanding of heat transport process in low-dimensional materials, with focus on the roles of defects, disorder, interfaces, and the quantum- mechanical effect. New physics uncovered from computational simulations, experimental studies, and predictable models will be reviewed, followed by a perspective on open challenges.
