Directional three-dimensional carbon-based foams are emerging as highly attractive candidates for promising electromagnetic wave absorbing materials(EWAMs)thanks to their unique architecture,but their construction usu...Directional three-dimensional carbon-based foams are emerging as highly attractive candidates for promising electromagnetic wave absorbing materials(EWAMs)thanks to their unique architecture,but their construction usually involves complex procedures and extremely depends on unidirectional freezing technique.Herein,we propose a groundbreaking approach that leverages the assemblies of salting-out protein induced by ammonium metatungstate(AM)as the precursor,and then acquire directional three-dimensional carbon-based foams through simple pyrolysis.The electrostatic interaction between AM and protein ensures well dispersion of WC_(1−x)nanoparticles on carbon frameworks.The content of WC_(1−x)nanoparticles can be rationally regulated by AM dosage,and it also affects the electromagnetic(EM)properties of final carbon-based foams.The optimized foam exhibits exceptional EM absorption performance,achieving a remarkable minimum reflection loss of−72.0 dB and an effective absorption bandwidth of 6.3 GHz when EM wave propagates parallel to the directional pores.Such performance benefits from the synergistic effects of macroporous architecture and compositional design.Although there is a directional dependence of EM absorption,radar stealth simulation demonstrates that these foams can still promise considerable reduction in radar cross section with the change of incident angle.Moreover,COMSOL simulation further identifies their good performance in preventing EM interference among different electronic components.展开更多
The rapid development of modern 5G technology has significantly increased the demand for multifunctional electromagnetic interference(EMI)shielding and wave-absorbing materials.Hence,a densification strategy was propo...The rapid development of modern 5G technology has significantly increased the demand for multifunctional electromagnetic interference(EMI)shielding and wave-absorbing materials.Hence,a densification strategy was proposed to fabricate multifunctional rigid polyimide(PI)composite foam.As a result,the composite PI foam exhibits excellent mechanical properties,with tensile and bending strengths of 4.7 and 21.1 MPa,respectively.Moreover,the composite PI foam achieves a promising EMI shielding performance with a high absorption coefficient(A)of 0.71,coupled with an X-band(8.2–12.4 GHz)EMI rating of 44 dB(2 mm)due to its high conductivity(20.29 ms/mm).Satisfyingly,the composite PI foam also has an optimal reflection loss(RL)of up to−46.4 dB and an effective absorption bandwidth(EAB)(RL<−10 dB)that covers the entire X-band.Meanwhile,the fabricated foam demonstrates a Joule heating performance of 89.2°C under supply voltages(3–9 V)and rapid response time(within 20 s)for stable and reproducible performance in long-term cycling.This work provides a versatile strategy for the development of lightweight and high-strength materials for EMI shielding and microwave absorption,demonstrating great potential for aerospace,microelectronics,and energy conversion applications.展开更多
Metal foams are a fascinating group of materials that possess distinct physicochEMIcal properties and interconnected strut features with high surface area-to-volume ratios, high specific strength and lightweight natur...Metal foams are a fascinating group of materials that possess distinct physicochEMIcal properties and interconnected strut features with high surface area-to-volume ratios, high specific strength and lightweight nature. These characteristics make them ideal for applications in vibration damping, heat insulation and weight reduction. In recent years, there has been increasing interest in the application of interfering energy conversion such as electromagnetic wave (EMW) and sound, where the metal foams could emerge as a solution. This paper will present a comprehensive review of the preparation methods as well as the interference energy converting mechanisms for metal foams. Typically, the progress and prospective aspects of metal foams for EMW absorption, electromagnetic interference (EMI) shielding and sound absorption have been emphasized. Through this review, we aspire to offer valuable insights for the development of multifunctional applications with metal foam materials.展开更多
This work explores the development of biodegradable laminar composite foams for cushioning applications.The focus lies on overcoming the inherent brittleness of starch foams by incorporating various paper types as rei...This work explores the development of biodegradable laminar composite foams for cushioning applications.The focus lies on overcoming the inherent brittleness of starch foams by incorporating various paper types as rein-forcement.Tapioca starch and glutinous starch were blended in varying ratios(100:0–0:100)to optimize the base material’s properties.The morphology,density,flexural strength,and impact strength of these starch blends were evaluated.The results revealed a trade-off between impact strength and density,with increasing glutinous starch content favoring impact resistance but also leading to higher density.The optimal ratio of tapioca to glutinous starch for achieving maximumflexural strength and modulus was determined to be 60:40.Theflexural strength of the composite material at this ratio reached a peak value of 5.3±0.6 MPa,significantly surpassing theflexural strength of pure tapioca foam,which was measured to be 3.5±0.4 MPa.Building on this foundation,novel lami-nar composite foams were fabricated using the 60:40 starch blend reinforced with mulberry paper,kraft paper,and newsprint paper.To enhance the interfacial adhesion between the starch matrix and paper reinforcement,a silane coupling agent was employed at a 10 wt%loading on the paper.The incorporation of paper reinforcement into starch foams was found to enhance their mechanical properties.Specifically,flexural strength values increased from 5.3±0.6 MPa for the unreinforced starch foam to 6.8±0.6 MPa,8.1±0.9 MPa,and 7.4±0.1 MPa when reinforced with mulberry paper,kraft paper,and newsprint paper,respectively.Notably,kraft paper reinforcement led to the most enhancements inflexural strength,flexural modulus,and impact strength.This research paves the way for developing sustainable cushioning materials with competitive mechanical properties using bio-based resources like starch and paper.展开更多
As modern communication and detection technologies advance at a swift pace,multifunctional electromagnetic interference(EMI)shielding materials with active/positive infrared stealth,hydrophobicity,and electric-thermal...As modern communication and detection technologies advance at a swift pace,multifunctional electromagnetic interference(EMI)shielding materials with active/positive infrared stealth,hydrophobicity,and electric-thermal conversion ability have received extensive attention.Meeting the aforesaid requirements simultaneously remains a huge challenge.In this research,the melamine foam(MF)/polypyrrole(PPy)nanowire arrays(MF@PPy)were fabricated via one-step electrochemical polymerization.The hierarchical MF@PPy foam was composed of three-dimensional PPy micro-skeleton and ordered PPy nanowire arrays.Due to the upwardly grown PPy nanowire arrays,the MF@PPy foam possessed good hydrophobicity ability with a water contact angle of 142.00°and outstanding stability under various harsh environments.Meanwhile,the MF@PPy foam showed excellent thermal insulation property on account of the low thermal conductivity and elongated ligament characteristic of PPy nanowire arrays.Furthermore,taking advantage of the high conductivity(128.2 S m^(-1)),the MF@PPy foam exhibited rapid Joule heating under 3 V,resulting in dynamic infrared stealth and thermal camouflage effects.More importantly,the MF@PPy foam exhibited remarkable EMI shielding effectiveness values of 55.77 dB and 19,928.57 dB cm^(2)g^(-1).Strong EMI shielding was put down to the hierarchically porous PPy structure,which offered outstanding impedance matching,conduction loss,and multiple attenuations.This innovative approach provides significant insights to the development of advanced multifunctional EMI shielding foams by constructing PPy nanowire arrays,showing great applications in both military and civilian fields.展开更多
Tannins are polyphenols widely present in the plant kingdom,commonly divided into two groups:condensed and hydrolysable tannins.Sustainable furanic bio-foams based on condensed tannins have been largely studied,but li...Tannins are polyphenols widely present in the plant kingdom,commonly divided into two groups:condensed and hydrolysable tannins.Sustainable furanic bio-foams based on condensed tannins have been largely studied,but little is described about the use of hydrolysable tannins for this material.This study examined the potential of hydrolysable chestnut tannin in comparison to condensed mimosa tannins to produce furanic foams by chemical expansion.Due to the low reactivity of the hydrolysable tannin,the use of an external source for its polymerization and curing was necessary.Through Fourier transform infrared spectroscopy(FTIR)chromatography,it was possible to observe that the new foams presented small differences in functional groups compared to the condensed tannin foams,presenting peaks related to carboxyl groups.In terms of physical properties,the chestnut foams showed an apparent density 36%higher than the conventional mimosa tannin foams and a superior hydrophilic character.In terms of thermal properties,both foams exhibit high thermal stability,with the acacia tannin foam being slightly superior.In summary,this research paves the way for new applications of hydrolysable tannins in bio-foams and materials science.展开更多
A single-phase anti-perovskite medium-entropy alloy nitride foams(MEANFs),as innovative materials for electromagnetic wave(EMW)absorption,have been successfully synthesized through the lattice expansion induced by nit...A single-phase anti-perovskite medium-entropy alloy nitride foams(MEANFs),as innovative materials for electromagnetic wave(EMW)absorption,have been successfully synthesized through the lattice expansion induced by nitrogen doping.This achievement notably overcomes the inherent constraints of conventional metal-based absorbers,including low resonance frequency,high conductivity,and elevated density,for the synergistic advantages provided by multimetallic alloys and foams.Microstructural analysis with comprehensive theoretical calculations provides in-depth insights into the formation mechanism,electronic structure,and magnetic moment of MEANFs.Furthermore,deliberate component design along with the foam structure proves to be an effective strategy for enhancing impedance matching and absorption.The results show that the MEANFs exhibit a minimum reflection loss(RL_(min))value of-60.32 dB and a maximum effective absorption bandwidth(EAB_(max))of 5.28 GHz at 1.69 mm.This augmentation of energy dissipation in EMW is predominantly attributed to factors such as porous structure,interfacial polarization,defect-induced polarization,and magnetic resonance.This study demonstrates a facile and efficient approach for synthesizing single-phase medium-entropy alloys,emphasizing their potential as materials for electromagnetic wave absorption due to their adjustable magnetic-dielectric properties.展开更多
To address the severe electromagnetic(EM)pollution and thermal exhaustion issues in modern electronics,C@Mn_(x)O_(y) foams were first reported as an advanced multifunctional filler with superior microwave absorption,R...To address the severe electromagnetic(EM)pollution and thermal exhaustion issues in modern electronics,C@Mn_(x)O_(y) foams were first reported as an advanced multifunctional filler with superior microwave absorption,Radar wave stealth,and thermal dissipation.They were synthesized using a simple one-step annealing route,in which PVP and in-situ generated gas bubbles play a crucial role in the foam formation.Our results show that the C@Mn_(x)O_(y) foams possess excellent electrical insulation and a large thermal conductivity of 3.58 W(m K)^(–1) at a low load of 5 wt.%.Also,they exhibit prominent microwave absorption capabilities(MWACs)with a strong absorption(–46.03 dB)and a wide bandwidth(11.04 GHz)in a low load(30 wt.%).When they are then used as a patch,the wideband Radar cross-section can be effectively reduced by up to 41.34 dB m^(2).This performance outperforms most other heterostructures.Furthermore,the mechanism of dielectric loss and thermal transfer at the atomic level is revealed by the First-principle calculations of the density of states(DOS)and the phonon density of states(PDOS).The combination of C,MnO,and Mn_(3)O_(4) disrupts local microstructure symmetry and induces extra electrical dipoles at the heterointerfaces,benefiting the enhanced MWACs of C@Mn_(x)O_(y) foams along with defect polarization and multiple scattering.Their enhanced TC could be credited to the co-transmission of low phonon-boundary/phonon-defect scattering and multiple-frequency phonons from C,MnO,and Mn_(3)O_(4).Overall,the C@Mn_(x)O_(y) foams are highly promising for application in EM protection,absorption,and thermal management.What is more,this study provides a theoretical guide for designing heterostructures as effective microwave absorbing and thermally conductive materials used in modern electronics.展开更多
Poly(vinylidene fluoride)(PVDF)foam has received widespread attention due to its high strength,and excellent combination of flame-retardancy,antibacterial performance,and chemical stability.However,the foaming ability...Poly(vinylidene fluoride)(PVDF)foam has received widespread attention due to its high strength,and excellent combination of flame-retardancy,antibacterial performance,and chemical stability.However,the foaming ability of conventional PvDF is severely limited by its rapid crystallization kinetics and poor melt strength.Although ultra-high molecular weight PVDF(H-PVDF)theoretically offers prolonged melt elasticity favorable for foaming,the extremely high melt viscosity poses substantial processing challenges,and its foaming behavior has remained largely unexplored.To address these issues,this study proposes a novel fabrication strategy combining solvent casting with microcellular foaming to prepare H-PVDF foams.Dynamic mechanical analysis and differential scanning calorimetry reveal that extensive chain entanglements in H-PVDF impose constraints on crystallization and significantly enhance melt strength.By tuning the processing parameters,the distinctive foaming be-havior of H-PVDF under various conditions is systematically elucidated.Remarkably,a record-high expansion ratio of 55.6-fold is achieved,ac-companied by a highly uniform and fine cellular structure.The resulting H-PVDF foams exhibit a low thermal conductivity of 31.8 mW·m^(-1).K^(-1),while retaining excellent compressive strength,flame-retardancy,and hydrophobicity.These outstanding properties highlight the great potential of H-PVDF foams as the thermal insulation materials for applications in aerospace,energy infrastructure,and other extreme environments.展开更多
Due to environmental concerns and the oil crisis,biodegradable polymer foams have garnered increasing attention.Among all biodegradable materials,Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)(P(HB-co-HV))distinguishes ...Due to environmental concerns and the oil crisis,biodegradable polymer foams have garnered increasing attention.Among all biodegradable materials,Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)(P(HB-co-HV))distinguishes itself with the advantage of being biodegradable in all natural environments.However,preparing P(HB-co-HV)foam with a fine cellular structure remains challenging.Herein,P(HBco-HV)foams with a double melting peak structure were developed.P(HB-co-HV)samples were first heated briefly near the melting temperature to melt most of the crystals,followed by saturation and foaming at a lower temperature(foaming temperature).P(HB-co-HV)foams with cell sizes of 7.1-30.0μm and relative densities ranging from 0.3 to 0.9 were prepared,and the foaming temperature window was as wide as 16℃.The effect of heat treatment temperature and foaming temperature on the crystallization and cell structure was investigated through DSC and SEM.It was found that the high-melting temperature crystals generated during the saturation step significantly improved the cell structure of P(HB-coHV),since these crystals can enhance the heterogeneous cell nucleation and hinder the cell growth during foaming.The low-melting temperature crystals were formed during foaming.In situ WAXD analysis during heating showed that the high-and low-melting peaks corresponded to HV-unit-excluded and HV-unit-included PHB crystals,respectively.展开更多
In this study,two series of foams based on tannic acid(TA),furfuryl alcohol(FA),soybean protein isolate(SPI),and casein(CA),namely TA–FA–SPI(TS series)and TA–FA–CA(TC series)were developed,and their properties wer...In this study,two series of foams based on tannic acid(TA),furfuryl alcohol(FA),soybean protein isolate(SPI),and casein(CA),namely TA–FA–SPI(TS series)and TA–FA–CA(TC series)were developed,and their properties were enhanced by adding poplar fibers(WF).From the samples produced,a complete set of characterization was performed including possible crosslinking reactions,morphology,mechanical properties,flame retardancy,thermal insulation and thermal stability.Fourier-transform infrared spectroscopy(FTIR)revealed possible covalent crosslinking among the components and hydrogen bonding between WF and the matrix.Viscosity results indicated that lower prepolymer viscosity led to lower apparent density,while WF addition reduced even more the density.Mechanical tests showed that the maximum compressive strengths were good,while WF improved the compressive strength by up to 56%.Scanning electron microscopy(SEM)showed uniform cell structures,but small open pores were observed.Two-dimensional(2D)CT scan images confirmed the good compatibility between WF and the matrix,with low anisotropy in the material.Friability tests indicated that WF decreased the pulverization ratio of the materials by up to 42%.Thermogravimetric analysis(TGA)showed good thermal stability of the materials up to 328°C.Vertical burning tests showed that the materials were self-extinguishing without residue(dripping).The lowest thermal conductivity was 0.04 W/m·K.These results suggest that these novel formaldehyde-free,high biomass content(95%–96%)foams and composite foams have high potential to replace traditional phenolic foams(PF)in applications such as construction,transportation,packaging,and thermal insulation.展开更多
Flexible polymer-based foam sensors have significant potential for application in wearable electronics and motion monitoring.However,these prospects are hindered by the complex and unenvironmentally friendly manufactu...Flexible polymer-based foam sensors have significant potential for application in wearable electronics and motion monitoring.However,these prospects are hindered by the complex and unenvironmentally friendly manufacturing processes.In this study,we employed melt blending and supercritical carbon dioxide foaming to fabricate an ethylene-vinyl acetate copolymer(EVA)/low-density polyethylene(LDPE)/carbon nanotube(CNT)piezoresistive foam sensor.The cross-linking agent bis(tert-butyldioxyisopropyl)benzene and the conductive filler CNT were incorporated into the EVA/LDPE composite,successfully achieving a chemically cross-linked and physically entangled composite structure that significantly enhanced the storage modulus and complex viscosity.Additionally,the compressive strength of EVA/LDPE/CNT foam with 10 parts per hundred rubber(phr)CNT reached 1.37 MPa at 50%compression,marking a 340%increase compared to the 0.31 MPa of the CNT-free sample.Furthermore,the EVA/LDPE/CNT composite foams,which incorporated 10 phr CNT,were prepared under specific foaming conditions,resulting in an ultra-low density of 0.11 g/cm^(3) and a higher sensitivity,with a gauge factor of–2.3.The piezoresistive foam sensors developed in this work could accurately detect human motion,thereby expanding their applications in the field of piezoresistive foam sensors and providing an effective strategy for the advancement of high-performance piezoresistive foam sensors.展开更多
Two cross⁃sectional configurations of thin⁃walled square tubes partially filled with lightweight metallic foams are proposed,and termed as double⁃cell configuration partially filled with foam(DC⁃PF)and double⁃tube con...Two cross⁃sectional configurations of thin⁃walled square tubes partially filled with lightweight metallic foams are proposed,and termed as double⁃cell configuration partially filled with foam(DC⁃PF)and double⁃tube configuration partially filled with foam(DT⁃PF),respectively.The bending crashworthiness is investigated based on three⁃point bending tests using finite element ABAQUS/Explicit code.The two key mechanical indicators including Crash Load Efficiency(CLE)and Specific Energy Absorption(SEA)are introduced to evaluate the effect of foams in comparison with empty square tubes and fully filled square tubes.The numerical results show that the two partially filled configurations,especially DT⁃PF,display dramatically excellent bending crashworthiness compared with empty and fully filled square tubes.There exists a foam density threshold,beyond which the CLE of DT⁃PF achieves a maximum constant.In addition,there seems to be another foam density threshold,beyond which the SEA of DT⁃PF gets to the maximum value.It is also shown that the foam density threshold corresponding to the maximum SEA varies with the thickness of thin⁃walled square tubes.展开更多
Aluminum foams were fabricated by melt-based route using ZrH2 as a foaming agent. The factors which affected the foaming of aluminum foams during casting process were investigated. The powdered zirconium hydride with ...Aluminum foams were fabricated by melt-based route using ZrH2 as a foaming agent. The factors which affected the foaming of aluminum foams during casting process were investigated. The powdered zirconium hydride with content of 0.6%-1.4% （mass fraction） was added to the molten pure aluminum and the foaming condition was controlled in a temperature range from 933 to 1 013 K, Ca amount of 1.5%-3.0% （mass fraction）, stirring time of 0.5-2.5 min and holding time of 1.5-4.0 min to obtain homogeneous aluminum foams. The fabricated aluminum foams were characterized by XRD, SEM and Image-pro plus. The mechanical properties of the aluminum foams with different relative density were tested. The result indicates that the foaming agent （ZrH2） is suitable for the preparation of small aperture aluminum foams with average pore diameter of 1 mm. Inter-metallic compounds and Al2O3 have effect on the melt viscosity. The aluminum foams experience linear elastic, platforms and densification process and had a higher efficiency of energy absorption.展开更多
Based on A356 aluminum alloy,aluminum foams were prepared by gas injection foaming process with pure nitrogen,air and some gas mixtures.The oxygen volume fraction of these gas mixtures varied from 0.2%to 8.0%.Optical ...Based on A356 aluminum alloy,aluminum foams were prepared by gas injection foaming process with pure nitrogen,air and some gas mixtures.The oxygen volume fraction of these gas mixtures varied from 0.2%to 8.0%.Optical microscopy,scanning electron microscopy（SEM） and Auger electron spectroscopy（AES） were used to analyze the influence of oxygen content on cell structure,relative density,macro and micro morphology of cell walls,coverage area fraction of oxide film,thickness of oxide film and other aspects.Results indicate that the coverage area fraction of oxide film on bubble surface increases with the increase of oxygen content when the oxygen volume is less than 1.2%.While when the oxygen volume fraction is larger than 1.6%,an oxide film covers the entire bubble surface and aluminum foams with good cell structure can be produced.The thicknesses of oxide films of aluminum foams produced by gas mixtures containing 1.6%-21%oxygen are almost the same.The reasons why the thickness of oxide film nearly does not change with the variation of oxygen content and the amount of oxygen needed to achieve 100%coverage of oxide film are both discussed.In addition,the role of oxide film on bubble surface in foam stability is also analyzed.展开更多
To improve the oxidation resistance of boron-modified carbon foams, the B2O3 coating was prepared on boron-modified carbon foams by low-cost slurry method. The microstructures and phase compositions of the coated carb...To improve the oxidation resistance of boron-modified carbon foams, the B2O3 coating was prepared on boron-modified carbon foams by low-cost slurry method. The microstructures and phase compositions of the coated carbon foams were characterized by scanning electron microscopy and X-ray diffraction, respectively. Oxidation resistances of uncoated and coated boron-modified carbon foams were investigated at 873 K in air. The results showed that as-received B2O3 coating could protect boron-modified carbon foams from oxidation at 873 K. B2O3-coated carbon foam doped with 7% B2O3 （mass fraction） （BO-7） had better oxidation resistance, exhibiting mass loss of 17.40% after oxidation at 873 K for 120 min. The melting glass layer formed on the surface of BO-7 could prevent oxygen from diffusing into boron-modified carbon foams substrate during oxidation to some extent.展开更多
In the range of 620？710 °C, air was blown into A356 aluminum alloy melt to produce aluminum foams. In order to study the influence of temperature on the thickness of oxide film on bubble surface, Auger electron ...In the range of 620？710 °C, air was blown into A356 aluminum alloy melt to produce aluminum foams. In order to study the influence of temperature on the thickness of oxide film on bubble surface, Auger electron spectroscopy （AES） was used. Based on the knowledge of corrosion science and hydrodynamics, two oxidation kinetics models of oxide film on bubble surface were established. The thicknesses of oxide films produced at different temperatures were predicted through those two models. Furthermore, the theoretical values were compared with the experimental values. The results indicate that in the range of 620？710 °C, the theoretical values of the thickness of oxide film predicted by the model including the rising process are higher than the experimental values. While, the theoretical values predicted by the model without the rising process are in good agreement with the experimental values, which shows this model objectively describes the oxidation process of oxide film on bubble surface. This work suggests that the oxidation kinetics of oxide film on bubble surface of aluminum foams produced by gas injection foaming process follows the Arrhenius equation.展开更多
CO2-copolymer based polyurethane foams were synthesized and characterized in this paper. The foams were found to have higher strength and lower heat of combustion than the conventional polyether polyurethane foams. ...CO2-copolymer based polyurethane foams were synthesized and characterized in this paper. The foams were found to have higher strength and lower heat of combustion than the conventional polyether polyurethane foams. They may find wide applications in many fields.展开更多
The porosity of titanium foams obtained from the space holder technique was theoretically analyzed in the cases of volume shrinking, retaining and expanding during sintering. The relationship between porosity and spac...The porosity of titanium foams obtained from the space holder technique was theoretically analyzed in the cases of volume shrinking, retaining and expanding during sintering. The relationship between porosity and spacer content was compared under different conditions. The kind of volume change of macropores during sintering was discussed. The results indicate that the relationship between porosity and spacer content depends on the decreased volume of macropores and the volume of micropores in cell-walls in the first case, while the porosity will be greater than the spacer content for the other two cases. It proves that the volume change of macropores during sintering decreases based on theory and practice.展开更多
SiC/Al-based composite foams were prepared by a two-step foaming method.The influence of the SiC content and its distribution uniformity on the foaming stability,cell structure,and mechanical properties of the aluminu...SiC/Al-based composite foams were prepared by a two-step foaming method.The influence of the SiC content and its distribution uniformity on the foaming stability,cell structure,and mechanical properties of the aluminum foams was investigated.The macro/micro-features of the aluminum foams were characterized and analyzed.Results demonstrate that an appropriate increase in SiC content and the uniform distribution of SiC can improve the foaming stability,optimize the cell diameter and cell wall thickness,ameliorate the cell distribution,and enhance the hardness and compressive strength of the aluminum foams.However,either insufficient or excessive SiC leads to uneven distribution of SiC particles,which is unfavorable to foaming stability and good cell structure formation.With 6wt%SiC,both the foaming stability and cell structure of the aluminum foam reach the optimal state,resulting in the highest compressive strength and optimal energy absorption capacity.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.22475057 and No.52373262).
文摘Directional three-dimensional carbon-based foams are emerging as highly attractive candidates for promising electromagnetic wave absorbing materials(EWAMs)thanks to their unique architecture,but their construction usually involves complex procedures and extremely depends on unidirectional freezing technique.Herein,we propose a groundbreaking approach that leverages the assemblies of salting-out protein induced by ammonium metatungstate(AM)as the precursor,and then acquire directional three-dimensional carbon-based foams through simple pyrolysis.The electrostatic interaction between AM and protein ensures well dispersion of WC_(1−x)nanoparticles on carbon frameworks.The content of WC_(1−x)nanoparticles can be rationally regulated by AM dosage,and it also affects the electromagnetic(EM)properties of final carbon-based foams.The optimized foam exhibits exceptional EM absorption performance,achieving a remarkable minimum reflection loss of−72.0 dB and an effective absorption bandwidth of 6.3 GHz when EM wave propagates parallel to the directional pores.Such performance benefits from the synergistic effects of macroporous architecture and compositional design.Although there is a directional dependence of EM absorption,radar stealth simulation demonstrates that these foams can still promise considerable reduction in radar cross section with the change of incident angle.Moreover,COMSOL simulation further identifies their good performance in preventing EM interference among different electronic components.
基金support from the Postgraduate Innovation Foundation of Xi'an Polytechnic University(No.chx2024034)the Natural Science Foundation of Shaanxi Province(No.2022JQ-362,2021JQ-677)the Scientific Research Program Funded by Shaanxi Provincial Education Department(No.21JK20180911).
文摘The rapid development of modern 5G technology has significantly increased the demand for multifunctional electromagnetic interference(EMI)shielding and wave-absorbing materials.Hence,a densification strategy was proposed to fabricate multifunctional rigid polyimide(PI)composite foam.As a result,the composite PI foam exhibits excellent mechanical properties,with tensile and bending strengths of 4.7 and 21.1 MPa,respectively.Moreover,the composite PI foam achieves a promising EMI shielding performance with a high absorption coefficient(A)of 0.71,coupled with an X-band(8.2–12.4 GHz)EMI rating of 44 dB(2 mm)due to its high conductivity(20.29 ms/mm).Satisfyingly,the composite PI foam also has an optimal reflection loss(RL)of up to−46.4 dB and an effective absorption bandwidth(EAB)(RL<−10 dB)that covers the entire X-band.Meanwhile,the fabricated foam demonstrates a Joule heating performance of 89.2°C under supply voltages(3–9 V)and rapid response time(within 20 s)for stable and reproducible performance in long-term cycling.This work provides a versatile strategy for the development of lightweight and high-strength materials for EMI shielding and microwave absorption,demonstrating great potential for aerospace,microelectronics,and energy conversion applications.
基金supported by the National Natural Science Foundation of China(No.52271180)the Leading Goose R&D Program of Zhejiang Province(2022C01110).
文摘Metal foams are a fascinating group of materials that possess distinct physicochEMIcal properties and interconnected strut features with high surface area-to-volume ratios, high specific strength and lightweight nature. These characteristics make them ideal for applications in vibration damping, heat insulation and weight reduction. In recent years, there has been increasing interest in the application of interfering energy conversion such as electromagnetic wave (EMW) and sound, where the metal foams could emerge as a solution. This paper will present a comprehensive review of the preparation methods as well as the interference energy converting mechanisms for metal foams. Typically, the progress and prospective aspects of metal foams for EMW absorption, electromagnetic interference (EMI) shielding and sound absorption have been emphasized. Through this review, we aspire to offer valuable insights for the development of multifunctional applications with metal foam materials.
基金funded by the Thailand Science Research and Innovation(TSRI)under Fundamental Fund 2023(Project:Advanced Materials and Manufacturing for Applications in New S-Curve Industries).
文摘This work explores the development of biodegradable laminar composite foams for cushioning applications.The focus lies on overcoming the inherent brittleness of starch foams by incorporating various paper types as rein-forcement.Tapioca starch and glutinous starch were blended in varying ratios(100:0–0:100)to optimize the base material’s properties.The morphology,density,flexural strength,and impact strength of these starch blends were evaluated.The results revealed a trade-off between impact strength and density,with increasing glutinous starch content favoring impact resistance but also leading to higher density.The optimal ratio of tapioca to glutinous starch for achieving maximumflexural strength and modulus was determined to be 60:40.Theflexural strength of the composite material at this ratio reached a peak value of 5.3±0.6 MPa,significantly surpassing theflexural strength of pure tapioca foam,which was measured to be 3.5±0.4 MPa.Building on this foundation,novel lami-nar composite foams were fabricated using the 60:40 starch blend reinforced with mulberry paper,kraft paper,and newsprint paper.To enhance the interfacial adhesion between the starch matrix and paper reinforcement,a silane coupling agent was employed at a 10 wt%loading on the paper.The incorporation of paper reinforcement into starch foams was found to enhance their mechanical properties.Specifically,flexural strength values increased from 5.3±0.6 MPa for the unreinforced starch foam to 6.8±0.6 MPa,8.1±0.9 MPa,and 7.4±0.1 MPa when reinforced with mulberry paper,kraft paper,and newsprint paper,respectively.Notably,kraft paper reinforcement led to the most enhancements inflexural strength,flexural modulus,and impact strength.This research paves the way for developing sustainable cushioning materials with competitive mechanical properties using bio-based resources like starch and paper.
基金supported by the Key Research and Development Program of Sichuan Province(Grant No.2023ZHCG0050)the Fundamental Research Funds for the Central Universities of China(Grant No.2682024QZ006 and 2682024ZTPY042)the Analytic and Testing Center of Southwest Jiaotong University.
文摘As modern communication and detection technologies advance at a swift pace,multifunctional electromagnetic interference(EMI)shielding materials with active/positive infrared stealth,hydrophobicity,and electric-thermal conversion ability have received extensive attention.Meeting the aforesaid requirements simultaneously remains a huge challenge.In this research,the melamine foam(MF)/polypyrrole(PPy)nanowire arrays(MF@PPy)were fabricated via one-step electrochemical polymerization.The hierarchical MF@PPy foam was composed of three-dimensional PPy micro-skeleton and ordered PPy nanowire arrays.Due to the upwardly grown PPy nanowire arrays,the MF@PPy foam possessed good hydrophobicity ability with a water contact angle of 142.00°and outstanding stability under various harsh environments.Meanwhile,the MF@PPy foam showed excellent thermal insulation property on account of the low thermal conductivity and elongated ligament characteristic of PPy nanowire arrays.Furthermore,taking advantage of the high conductivity(128.2 S m^(-1)),the MF@PPy foam exhibited rapid Joule heating under 3 V,resulting in dynamic infrared stealth and thermal camouflage effects.More importantly,the MF@PPy foam exhibited remarkable EMI shielding effectiveness values of 55.77 dB and 19,928.57 dB cm^(2)g^(-1).Strong EMI shielding was put down to the hierarchically porous PPy structure,which offered outstanding impedance matching,conduction loss,and multiple attenuations.This innovative approach provides significant insights to the development of advanced multifunctional EMI shielding foams by constructing PPy nanowire arrays,showing great applications in both military and civilian fields.
基金supported by a grant overseen by the French National Research Agency(ANR),as part of the“Investissements d’Avenir”program(ANR-11-LABX-0002-01,Lab of Excellence ARBRE)supported by“Lorraine Universitéd’Excellence”Master Grant,ORION program and by the French Ministry of Foreign Office through EIFFEL program.
文摘Tannins are polyphenols widely present in the plant kingdom,commonly divided into two groups:condensed and hydrolysable tannins.Sustainable furanic bio-foams based on condensed tannins have been largely studied,but little is described about the use of hydrolysable tannins for this material.This study examined the potential of hydrolysable chestnut tannin in comparison to condensed mimosa tannins to produce furanic foams by chemical expansion.Due to the low reactivity of the hydrolysable tannin,the use of an external source for its polymerization and curing was necessary.Through Fourier transform infrared spectroscopy(FTIR)chromatography,it was possible to observe that the new foams presented small differences in functional groups compared to the condensed tannin foams,presenting peaks related to carboxyl groups.In terms of physical properties,the chestnut foams showed an apparent density 36%higher than the conventional mimosa tannin foams and a superior hydrophilic character.In terms of thermal properties,both foams exhibit high thermal stability,with the acacia tannin foam being slightly superior.In summary,this research paves the way for new applications of hydrolysable tannins in bio-foams and materials science.
基金supported by the National Natural Science Foundation of China(Grant No.52071294)the National Key Research and Development Program(Grant No.2022YFE0109800)the Natural Science Foundation of Zhejiang Province(Grant No.LY20E020015).
文摘A single-phase anti-perovskite medium-entropy alloy nitride foams(MEANFs),as innovative materials for electromagnetic wave(EMW)absorption,have been successfully synthesized through the lattice expansion induced by nitrogen doping.This achievement notably overcomes the inherent constraints of conventional metal-based absorbers,including low resonance frequency,high conductivity,and elevated density,for the synergistic advantages provided by multimetallic alloys and foams.Microstructural analysis with comprehensive theoretical calculations provides in-depth insights into the formation mechanism,electronic structure,and magnetic moment of MEANFs.Furthermore,deliberate component design along with the foam structure proves to be an effective strategy for enhancing impedance matching and absorption.The results show that the MEANFs exhibit a minimum reflection loss(RL_(min))value of-60.32 dB and a maximum effective absorption bandwidth(EAB_(max))of 5.28 GHz at 1.69 mm.This augmentation of energy dissipation in EMW is predominantly attributed to factors such as porous structure,interfacial polarization,defect-induced polarization,and magnetic resonance.This study demonstrates a facile and efficient approach for synthesizing single-phase medium-entropy alloys,emphasizing their potential as materials for electromagnetic wave absorption due to their adjustable magnetic-dielectric properties.
基金financially supported by the National Natural Science Foundation of China(No.52073260)the Zhejiang Provincial Natural Science Foundation of China(Nos.LGG21E020002 and LZ24E020004)the Major industrial projects of Jinhua City(No.2024A11011).
文摘To address the severe electromagnetic(EM)pollution and thermal exhaustion issues in modern electronics,C@Mn_(x)O_(y) foams were first reported as an advanced multifunctional filler with superior microwave absorption,Radar wave stealth,and thermal dissipation.They were synthesized using a simple one-step annealing route,in which PVP and in-situ generated gas bubbles play a crucial role in the foam formation.Our results show that the C@Mn_(x)O_(y) foams possess excellent electrical insulation and a large thermal conductivity of 3.58 W(m K)^(–1) at a low load of 5 wt.%.Also,they exhibit prominent microwave absorption capabilities(MWACs)with a strong absorption(–46.03 dB)and a wide bandwidth(11.04 GHz)in a low load(30 wt.%).When they are then used as a patch,the wideband Radar cross-section can be effectively reduced by up to 41.34 dB m^(2).This performance outperforms most other heterostructures.Furthermore,the mechanism of dielectric loss and thermal transfer at the atomic level is revealed by the First-principle calculations of the density of states(DOS)and the phonon density of states(PDOS).The combination of C,MnO,and Mn_(3)O_(4) disrupts local microstructure symmetry and induces extra electrical dipoles at the heterointerfaces,benefiting the enhanced MWACs of C@Mn_(x)O_(y) foams along with defect polarization and multiple scattering.Their enhanced TC could be credited to the co-transmission of low phonon-boundary/phonon-defect scattering and multiple-frequency phonons from C,MnO,and Mn_(3)O_(4).Overall,the C@Mn_(x)O_(y) foams are highly promising for application in EM protection,absorption,and thermal management.What is more,this study provides a theoretical guide for designing heterostructures as effective microwave absorbing and thermally conductive materials used in modern electronics.
基金supported by the National Natural Science Foundation of China(No.52175341)Shandong Provincial Natural Science Foundation(No.ZR2022JQ24)+2 种基金Funding Project of Jinan City's New Twenty Items for Colleges and Universities(No.202333038)Excellent Young Team Project of Central Universities(No.2023QNTD002)Qingdao Key Technology Research and Industrialization Demonstration Project(No.24-1-2-qljh-10-gx).
文摘Poly(vinylidene fluoride)(PVDF)foam has received widespread attention due to its high strength,and excellent combination of flame-retardancy,antibacterial performance,and chemical stability.However,the foaming ability of conventional PvDF is severely limited by its rapid crystallization kinetics and poor melt strength.Although ultra-high molecular weight PVDF(H-PVDF)theoretically offers prolonged melt elasticity favorable for foaming,the extremely high melt viscosity poses substantial processing challenges,and its foaming behavior has remained largely unexplored.To address these issues,this study proposes a novel fabrication strategy combining solvent casting with microcellular foaming to prepare H-PVDF foams.Dynamic mechanical analysis and differential scanning calorimetry reveal that extensive chain entanglements in H-PVDF impose constraints on crystallization and significantly enhance melt strength.By tuning the processing parameters,the distinctive foaming be-havior of H-PVDF under various conditions is systematically elucidated.Remarkably,a record-high expansion ratio of 55.6-fold is achieved,ac-companied by a highly uniform and fine cellular structure.The resulting H-PVDF foams exhibit a low thermal conductivity of 31.8 mW·m^(-1).K^(-1),while retaining excellent compressive strength,flame-retardancy,and hydrophobicity.These outstanding properties highlight the great potential of H-PVDF foams as the thermal insulation materials for applications in aerospace,energy infrastructure,and other extreme environments.
基金financially supported by the National Natural Science Foundation of China(No.51973097)S&T Innovation 2035 Major Special Programme of Ningbo(No.2024Z105)。
文摘Due to environmental concerns and the oil crisis,biodegradable polymer foams have garnered increasing attention.Among all biodegradable materials,Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)(P(HB-co-HV))distinguishes itself with the advantage of being biodegradable in all natural environments.However,preparing P(HB-co-HV)foam with a fine cellular structure remains challenging.Herein,P(HBco-HV)foams with a double melting peak structure were developed.P(HB-co-HV)samples were first heated briefly near the melting temperature to melt most of the crystals,followed by saturation and foaming at a lower temperature(foaming temperature).P(HB-co-HV)foams with cell sizes of 7.1-30.0μm and relative densities ranging from 0.3 to 0.9 were prepared,and the foaming temperature window was as wide as 16℃.The effect of heat treatment temperature and foaming temperature on the crystallization and cell structure was investigated through DSC and SEM.It was found that the high-melting temperature crystals generated during the saturation step significantly improved the cell structure of P(HB-coHV),since these crystals can enhance the heterogeneous cell nucleation and hinder the cell growth during foaming.The low-melting temperature crystals were formed during foaming.In situ WAXD analysis during heating showed that the high-and low-melting peaks corresponded to HV-unit-excluded and HV-unit-included PHB crystals,respectively.
基金funded by the Natural Sciences and Engineering Research Council of Canada(NSERC)for financial support,Grant Nos.CG125664 and GF136078.
文摘In this study,two series of foams based on tannic acid(TA),furfuryl alcohol(FA),soybean protein isolate(SPI),and casein(CA),namely TA–FA–SPI(TS series)and TA–FA–CA(TC series)were developed,and their properties were enhanced by adding poplar fibers(WF).From the samples produced,a complete set of characterization was performed including possible crosslinking reactions,morphology,mechanical properties,flame retardancy,thermal insulation and thermal stability.Fourier-transform infrared spectroscopy(FTIR)revealed possible covalent crosslinking among the components and hydrogen bonding between WF and the matrix.Viscosity results indicated that lower prepolymer viscosity led to lower apparent density,while WF addition reduced even more the density.Mechanical tests showed that the maximum compressive strengths were good,while WF improved the compressive strength by up to 56%.Scanning electron microscopy(SEM)showed uniform cell structures,but small open pores were observed.Two-dimensional(2D)CT scan images confirmed the good compatibility between WF and the matrix,with low anisotropy in the material.Friability tests indicated that WF decreased the pulverization ratio of the materials by up to 42%.Thermogravimetric analysis(TGA)showed good thermal stability of the materials up to 328°C.Vertical burning tests showed that the materials were self-extinguishing without residue(dripping).The lowest thermal conductivity was 0.04 W/m·K.These results suggest that these novel formaldehyde-free,high biomass content(95%–96%)foams and composite foams have high potential to replace traditional phenolic foams(PF)in applications such as construction,transportation,packaging,and thermal insulation.
基金supported by the National Natural Science Foundation of China(No.52473026)。
文摘Flexible polymer-based foam sensors have significant potential for application in wearable electronics and motion monitoring.However,these prospects are hindered by the complex and unenvironmentally friendly manufacturing processes.In this study,we employed melt blending and supercritical carbon dioxide foaming to fabricate an ethylene-vinyl acetate copolymer(EVA)/low-density polyethylene(LDPE)/carbon nanotube(CNT)piezoresistive foam sensor.The cross-linking agent bis(tert-butyldioxyisopropyl)benzene and the conductive filler CNT were incorporated into the EVA/LDPE composite,successfully achieving a chemically cross-linked and physically entangled composite structure that significantly enhanced the storage modulus and complex viscosity.Additionally,the compressive strength of EVA/LDPE/CNT foam with 10 parts per hundred rubber(phr)CNT reached 1.37 MPa at 50%compression,marking a 340%increase compared to the 0.31 MPa of the CNT-free sample.Furthermore,the EVA/LDPE/CNT composite foams,which incorporated 10 phr CNT,were prepared under specific foaming conditions,resulting in an ultra-low density of 0.11 g/cm^(3) and a higher sensitivity,with a gauge factor of–2.3.The piezoresistive foam sensors developed in this work could accurately detect human motion,thereby expanding their applications in the field of piezoresistive foam sensors and providing an effective strategy for the advancement of high-performance piezoresistive foam sensors.
基金Sponsored by National Natural Science Foundation of China (Grant Nos.12272064 and 12101086)University Natural Science Research Project of Anhui Province (Grant No.KJ2018A0481)+2 种基金Major Project of Basic Science (Natural Science) Research in Jiangsu Universities (Grant Nos.22KJA460001,23KJA580001)Changzhou Science and Technology Plan Project (Grant No.CE20235049)Changzhou Leading Innovative Talents C ultivation Project (Grant No.CQ20220092).
文摘Two cross⁃sectional configurations of thin⁃walled square tubes partially filled with lightweight metallic foams are proposed,and termed as double⁃cell configuration partially filled with foam(DC⁃PF)and double⁃tube configuration partially filled with foam(DT⁃PF),respectively.The bending crashworthiness is investigated based on three⁃point bending tests using finite element ABAQUS/Explicit code.The two key mechanical indicators including Crash Load Efficiency(CLE)and Specific Energy Absorption(SEA)are introduced to evaluate the effect of foams in comparison with empty square tubes and fully filled square tubes.The numerical results show that the two partially filled configurations,especially DT⁃PF,display dramatically excellent bending crashworthiness compared with empty and fully filled square tubes.There exists a foam density threshold,beyond which the CLE of DT⁃PF achieves a maximum constant.In addition,there seems to be another foam density threshold,beyond which the SEA of DT⁃PF gets to the maximum value.It is also shown that the foam density threshold corresponding to the maximum SEA varies with the thickness of thin⁃walled square tubes.
基金Project (2004AA33G060) supported by the National High-tech Research and Development Program of China
文摘Aluminum foams were fabricated by melt-based route using ZrH2 as a foaming agent. The factors which affected the foaming of aluminum foams during casting process were investigated. The powdered zirconium hydride with content of 0.6%-1.4% （mass fraction） was added to the molten pure aluminum and the foaming condition was controlled in a temperature range from 933 to 1 013 K, Ca amount of 1.5%-3.0% （mass fraction）, stirring time of 0.5-2.5 min and holding time of 1.5-4.0 min to obtain homogeneous aluminum foams. The fabricated aluminum foams were characterized by XRD, SEM and Image-pro plus. The mechanical properties of the aluminum foams with different relative density were tested. The result indicates that the foaming agent （ZrH2） is suitable for the preparation of small aperture aluminum foams with average pore diameter of 1 mm. Inter-metallic compounds and Al2O3 have effect on the melt viscosity. The aluminum foams experience linear elastic, platforms and densification process and had a higher efficiency of energy absorption.
基金Project(51371104)supported by the National Natural Science Foundation of China
文摘Based on A356 aluminum alloy,aluminum foams were prepared by gas injection foaming process with pure nitrogen,air and some gas mixtures.The oxygen volume fraction of these gas mixtures varied from 0.2%to 8.0%.Optical microscopy,scanning electron microscopy（SEM） and Auger electron spectroscopy（AES） were used to analyze the influence of oxygen content on cell structure,relative density,macro and micro morphology of cell walls,coverage area fraction of oxide film,thickness of oxide film and other aspects.Results indicate that the coverage area fraction of oxide film on bubble surface increases with the increase of oxygen content when the oxygen volume is less than 1.2%.While when the oxygen volume fraction is larger than 1.6%,an oxide film covers the entire bubble surface and aluminum foams with good cell structure can be produced.The thicknesses of oxide films of aluminum foams produced by gas mixtures containing 1.6%-21%oxygen are almost the same.The reasons why the thickness of oxide film nearly does not change with the variation of oxygen content and the amount of oxygen needed to achieve 100%coverage of oxide film are both discussed.In addition,the role of oxide film on bubble surface in foam stability is also analyzed.
基金Projects(51072107,51272213,51221001)supported by the National Natural Science Foundation of ChinaProject(B08040)supported by the Program of Introducing Talents of Discipline to Universities of China("111" Project)
文摘To improve the oxidation resistance of boron-modified carbon foams, the B2O3 coating was prepared on boron-modified carbon foams by low-cost slurry method. The microstructures and phase compositions of the coated carbon foams were characterized by scanning electron microscopy and X-ray diffraction, respectively. Oxidation resistances of uncoated and coated boron-modified carbon foams were investigated at 873 K in air. The results showed that as-received B2O3 coating could protect boron-modified carbon foams from oxidation at 873 K. B2O3-coated carbon foam doped with 7% B2O3 （mass fraction） （BO-7） had better oxidation resistance, exhibiting mass loss of 17.40% after oxidation at 873 K for 120 min. The melting glass layer formed on the surface of BO-7 could prevent oxygen from diffusing into boron-modified carbon foams substrate during oxidation to some extent.
基金Project(51371104)supported by the National Nature Science Foundation of China
文摘In the range of 620？710 °C, air was blown into A356 aluminum alloy melt to produce aluminum foams. In order to study the influence of temperature on the thickness of oxide film on bubble surface, Auger electron spectroscopy （AES） was used. Based on the knowledge of corrosion science and hydrodynamics, two oxidation kinetics models of oxide film on bubble surface were established. The thicknesses of oxide films produced at different temperatures were predicted through those two models. Furthermore, the theoretical values were compared with the experimental values. The results indicate that in the range of 620？710 °C, the theoretical values of the thickness of oxide film predicted by the model including the rising process are higher than the experimental values. While, the theoretical values predicted by the model without the rising process are in good agreement with the experimental values, which shows this model objectively describes the oxidation process of oxide film on bubble surface. This work suggests that the oxidation kinetics of oxide film on bubble surface of aluminum foams produced by gas injection foaming process follows the Arrhenius equation.
基金This project was supported by the National Natural Science Foundation of China(No.20274053).
文摘CO2-copolymer based polyurethane foams were synthesized and characterized in this paper. The foams were found to have higher strength and lower heat of combustion than the conventional polyether polyurethane foams. They may find wide applications in many fields.
基金Project(51174243)supported by the National Natural Science Foundation of ChinaProject(106112015CDJZR135502)supported by the Fundamental Research Funds for the Central Universities,China
文摘The porosity of titanium foams obtained from the space holder technique was theoretically analyzed in the cases of volume shrinking, retaining and expanding during sintering. The relationship between porosity and spacer content was compared under different conditions. The kind of volume change of macropores during sintering was discussed. The results indicate that the relationship between porosity and spacer content depends on the decreased volume of macropores and the volume of micropores in cell-walls in the first case, while the porosity will be greater than the spacer content for the other two cases. It proves that the volume change of macropores during sintering decreases based on theory and practice.
基金Doctoral Startup Fund(20192066,20212028)Laijin Excellent Doctoral Fund(20202021)+1 种基金Scientific and Technological Innovation of Colleges and Universities in Shanxi Province(2020L0342)Fundamental Research Program of Shanxi Province(202303021222178)。
文摘SiC/Al-based composite foams were prepared by a two-step foaming method.The influence of the SiC content and its distribution uniformity on the foaming stability,cell structure,and mechanical properties of the aluminum foams was investigated.The macro/micro-features of the aluminum foams were characterized and analyzed.Results demonstrate that an appropriate increase in SiC content and the uniform distribution of SiC can improve the foaming stability,optimize the cell diameter and cell wall thickness,ameliorate the cell distribution,and enhance the hardness and compressive strength of the aluminum foams.However,either insufficient or excessive SiC leads to uneven distribution of SiC particles,which is unfavorable to foaming stability and good cell structure formation.With 6wt%SiC,both the foaming stability and cell structure of the aluminum foam reach the optimal state,resulting in the highest compressive strength and optimal energy absorption capacity.
