Fabrication Of Foams Research Articles

Rapid Fabrication of Polyvinyl Alcohol Hydrogel Foams With Encapsulated Mesenchymal Stem Cells for Chronic Wound Treatment.

Chronic wounds present a major healthcare challenge around the world, and significant hurdles remain in their effective treatment due to limitations in accessible treatment options. Mesenchymal stem cells (MSCs) with multifunctional differentiation and modulatory properties have been delivered to chronic wounds to enhance closure but have limited engraftment when delivered without a scaffold. In this study, hybrid porous hydrogel foams composed of modified polyvinyl alcohol and gelatin were developed that are suitable for rapid and facile MSC encapsulation, fully degradable, and supportive of wound healing. Rapid fabrication and encapsulation within porous foams was achieved using a cytocompatible gas blowing process. The hybrid hydrogels have tunable degradation rates based on chemistry, with complete mass loss achieved within 2-6 weeks, which is compatible with chronic wound closure rates. High encapsulated A375 epithelial cell and MSC viability with maintained cell functionality over 2 weeks reveals the potential of these hydrogels to serve as cell delivery systems for chronic wound treatment. An exvivo porcine skin wound model demonstrated enhanced healing after application of cell-laden hydrogel foams. Overall, hybrid hydrogel foams with encapsulated therapeutic cells have the capacity for robust wound healing and are a promising platform for chronic wound dressings.

Fabrication of polypropylene/carbon fiber/carbon black composite foam bonded with continuous carbon fiber reinforced polypropylene prepregs via high-pressure foam injection molding

The fabrication of polymer composite foams with several functions offers various advantages. Herein, we reported a highly efficient and mass-produced method for preparing polypropylene/carbon fiber/carbon black (PP/CF/CB) composite foams bonded with continuous CF reinforced PP prepregs. CFs were uniformly dispersed in PP via melt blending, but some agglomerations of CBs were observed owing to their little size. Compared with pure PP, the introduction of CB improved the thermal stability and flame retardance of composites. Owing to the homogeneity of polymer between composites and prepregs, they were well bonded by injection molding. The tensile strength of the samples bonded with prepregs was improved by 158.3–257.7 % for different filler contents. As CF and CB played the role of heterogeneous nucleation, and the high-pressure foam injection molding could easily tailor cellular structure by adjusting the holding time and mold temperature, composite foams bonded with two prepregs and with desired cells were successfully prepared. The injected foams with two prepregs had an enhanced electromagnetic interference shielding performance, which was 65.4 dB when the content was 10 wt% and 15 wt% for CF and CB, respectively. This work provides a universal approach for efficient and large-scale preparation of lightweight and multifunctional polymer composite foams.

Sustainable fabrication of lightweight geopolymer foams from silica-fume and zeolite tuffs: Utilizing Al as foaming agent for thermal insulation

In response to the increasing demand for eco-friendly thermal insulation materials in construction, this research focuses on the development of geopolymer foams with optimized thermal insulation properties. The study employs silica fume and zeolite tuff as primary raw materials, activated by sodium hydroxide and sodium silicate solution, and incorporates aluminum powder and sodium lauryl sulfate (SLS) as additives to enhance porosity and refine pore size distribution. A comprehensive analysis of technical properties, including compressive strength, porosity, bulk density, and thermal conductivity, is conducted to assess the influence of these additives. The findings demonstrate that SLS plays a main role in modifying the microstructure, resulting in more uniform and interconnected pores. The addition of moderate amounts of SLS (0.9 wt%) promotes the formation of consistent cell sizes and porosity, contributing to the overall structural integrity of the foams. The foams are predominantly amorphous, with some residual crystalline phases observed. Scanning electron microscopy (SEM) reveals the development of sodium aluminum silicate whiskers, which serve as reinforcement, enhancing the mechanical strength of the geopolymer matrix. The resulting geopolymer foams exhibit high porosity (64.36–81.32 %), low thermal conductivity (0.29–0.07 W/m·K), and sufficient compressive strength (0.96–2.71 MPa), indicating their potential as sustainable insulation materials for construction applications.

Microstructure Analysis and Performance Study of Wood Lignin-Derived Carbon Foam Electrode for Sodium-Ion Batteries

Carbon foams (CF) offer a promising avenue for advancing energy storage systems due to their unique structure characterized by interconnected open-cell pores and surface-residing carbon nanofibers [1,2]. This structure provides tunability to the porosity, pore structure and size, which makes them ideal for high-energy dense electrodes for energy storage devices. Lignin-derived foams are particularly noteworthy as they utilize an abundant waste stream from paper products, offering a sustainable alternative to fossil-fuel-derived carbons often used in batteries. CFs can serve as electrodes or hosts for energy storage devices based on porosity, pore structure and size, and degree of graphitization, which significantly influences battery capacity, reversibility, and electrochemical reactions [3]. Utilizing natural CF from kraft lignin not only minimizes impacts compared to fossil-fuel-derived carbon sources [4] but also cuts production costs [2], making them an attractive option for large-scale energy storage systems.In this investigation, we examined lignin-derived CFs with differing porosity and pore structures, carbonized across a temperature range of 800°C to 1300°C. Various characterization techniques corroborated the transition from disordered to ordered carbon structure, escalating the graphitization with the increased carbonization temperatures. Pouch cells are assembled using a standard sodium-based electrolyte. Half-cells demonstrated reversible capacities surpassing 200 mAh/g at C/10, affirming the potential of lignin-derived CF-based Na-ion batteries for large-scale energy storage applications. The performance is studied as a function of CF microstructure, porosity, pore structure and size, particle size, and degree of graphitization for a fundamental understanding of the CF electrode. In conclusion, utilizing sodium and lignin, both abundant and low-cost materials, presents a promising avenue for the energy storage industry on a large scale. REFERENCES [1] F. Xu, Y. Gui, S. Zuo, J. Li, S. Wang, Preparation of lignin-based carbon foam monoliths with high strength and developed micrometer-sized cell/nano-sized porous structures using a self-bubbling method, J Anal Appl Pyrolysis 163 (2022).[2] Q. Yan, R. Arango, J. Li, Z. Cai, Fabrication and characterization of carbon foams using 100% Kraft lignin, Mater Des 201 (2021).[3] X.Y. Cui, Y.J. Wang, H.D. Wu, X.D. Lin, S. Tang, P. Xu, H.G. Liao, M. Sen Zheng, Q.F. Dong, A Carbon Foam with Sodiophilic Surface for Highly Reversible, Ultra-Long Cycle Sodium Metal Anode, Advanced Science 8 (2021).[4] S.F. Schneider, C. Bauer, P. Novák, E.J. Berg, A modeling framework to assess specific energy, costs and environmental impacts of Li-ion and Na-ion batteries, Sustain Energy Fuels 3 (2019) 3061–3070.

Biopolymer foams composed of hydroxypropyl cellulose: Fabrication, aqueous stability, and mechanical integrity

We describe the fabrication of biopolymer foams formed from aqueous solutions of hydroxypropyl cellulose, whereby freezing-induced phase-separation and solvent removal yields robust foam structures that are elastic in air and when wet, and that are stable to repeated compression when fully saturated with water. Through mechanisms of phase-separation, pore formation, and covalent crosslinking, we discovered effective methods to prepare microporous HPC foams that resist gelation even when exposed to water for long time frames (at least months). Employing multifunctional carboxylic acid crosslinkers allowed the foams to maintain their integrity when dry or wet, while the presence of α-cellulose as an additive further augmented their mechanical integrity and provided a means to adjust elasticity. The amount of crosslinker employed in the foaming process significantly impacted foam stability and water uptake, while polymeric crosslinkers enabled insertion of sulfobetaine zwitterionic moieties into the foams. Notably, the thermal transition characteristic of HPC solutions and gels proved operative in foam form, as seen in release of water from a saturated HPC foam using a combination of compressive and thermal mechanisms.

Enhancing Force Absorption, Stress-Strain and Thermal Properties of Weft-Knitted Inlay Spacer Fabric Structures for Apparel Applications.

The pursuit of materials that offer both wear comfort and protection for functional and protective clothing has led to the exploration of weft-knitted spacer structures. Traditional cushioning materials such as spacer fabrics and laminated foam often suffer from deformation under compression stresses, thus compromising their protective properties. This study investigates the enhancement of the force absorption, stress-strain, and thermal properties of weft-knitted spacer fabrics with inlays. Surface yarns with superior stretchability and thermal properties are used and combined with elastic yarns in various patterns to fabricate nine different inlay samples. The mechanical and thermal properties of these samples are systematically analyzed, including their compression, stretchability, thermal comfort, and surface properties. The results show that the inlay spacer fabric exhibits superior compression properties and thermal conductivity compared to traditional laminated foam and spacer fabrics while maintaining stretchability, thus providing better performance than traditional fabrics for protective clothing and wearable cushioning products. This study further confirms that the type of inlay yarn and inlay structure are crucial factors that significantly influence the thermal, tensile, and compressive properties of the fabric. This research provides valuable insights into the design and development of advanced textile structures to improve wear comfort and protection in close-fitting apparel applications.

One-Step Spraying Strategy for Fabricating Bioinspired, Graphene-Based, and Multifunctional-Integrated Coatings on Structural Steel with Good Water Repellency, Fireproofing, Anticorrosion, and Durability.

Traditionally, many coatings were merely concentrated on settling the inherent fire protection problem of steel structures, while surface contamination and corrosion susceptibility should also be considered. Concurrently addressing these problems in fireproof efficiency and surface multifunctionality has become an issue of great significance in further expanding the application value in industrial and daily scenarios. Based on this condition, ecofriendly, graphene-based, and superhydrophobic coatings with multifunctional integration were constructed on steel via a one-step spraying method. The as-prepared coatings mainly consist of epoxy resin (EP), silicone resin (SR), a cyclodextrin-based flame retardant (MCDPM), expandable graphite (EG), and multilayered graphene (MG). The results demonstrate that the water contact angle (WCA) and water sliding angle (WSA) of as-prepared coatings can reach 156.8 ± 1.6 and 5.8 ± 0.7°, respectively, revealing good water repellency and self-cleaning properties. The coatings can also exhibit adequate adaptability for various substrates including wood, polyurethane foam, and cotton fabrics. Besides, good durability and robustness of coatings have been also verified via acid/alkali immersion, outdoor exposure, O2/plasma etching, and linear abrasion tests. Simultaneously, the coatings can exhibit excellent anticorrosion capacity for steel materials via a double barrier effect. Most importantly, the coatings have exhibited the lowest backside temperature (234.5 °C) during fire impact tests, suggesting excellent fireproof and heat insulation performance. This fact can be ascribed to the conjunct action between the physical/chemical charring process of flame retardants and the remarkable thermal stability of graphene. Consequently, this article can be expected to further promote the development and application of multifunctional-integrated coatings for steel structures in more fields.

Morphology of Copper Nanofoams for Radiation Hydrodynamics and Fusion Applications Investigated by 3D Ptychotomography.

The performance of metal and polymer foams used in inertial confinement fusion (ICF), inertial fusion energy (IFE), and high-energy-density (HED) experiments is currently limited by our understanding of their nanostructure and its variation in bulk material. We utilized an X-ray-free electron laser (XFEL) together with lensless X-ray imaging techniques to probe the 3D morphology of copper foams at nanoscale resolution (28 nm). The observed morphology of the thin shells is more varied than expected from previous characterizations, with a large number of them distorted, merged, or open, and a targeted mass density 14% less than calculated. This nanoscale information can be used to directly inform and improve foam modeling and fabrication methods to create a tailored material response for HED experiments.

Fabrication of lightweight polyethersulfone foams with enhanced surface quality and high specific flexural properties using micro‐opening microcellular injection molding

AbstractPolyethersulfone (PES) is distinguished by its exceptional comprehensive properties, making it a highly valued engineering plastic employed in various cutting‐edge fields. However, the high cost of PES limits its wider application in industrial fields. Considering the cost‐reduction advantages of polymer foaming, PES foams were successfully prepared in this work using microcellular injection molding (MIM) and micro‐opening microcellular injection molding (MOMIM) foaming methods. Compared with the MIM foaming method, the PES foam samples prepared by the MOMIM foaming method have better microcellular structure and surface quality. As the micro‐opening distance increased, the cell density of the PES foam samples showed a gradual rise before plateauing, with the cell size remaining relatively constant. As a result, the density of the PES foam sample dropped to 1.07 g/cm3, which is 80.5% of the solid PES sample. Meanwhile, the mechanical properties of the PES foam samples remained robust, with both the specific flexural modulus and the specific flexural strength showing increases as the micro‐opening distance increased. The knowledge obtained from this study provides a method for preparing high‐performance PES foam materials, which will facilitate the application of PES in more civilian fields.

Fabrication of multifunctional polyimide foams with co-polymerized benzimidazole moieties for excellent thermal insulation and flame retardancy applications

In this study, heterocyclic diamine 2-(4-aminophenyl)-5-aminobenzimidazole (APBIA) was employed as a co-polymerization component to improve the properties of polyimide foams (PIFs) which were synthesized from 3,3′,4,4′-benzophenone tetracarboxylic acid dianhydride (BTDA) and 4,4′-diaminodiphenyl ether (ODA). The rheological behavior of polyester ammonium salt (PEAS) precursors was regulated by introducing APBIA moieties to the chain backbones, which affected the foaming behavior of PEAS and the microstructure of corresponding PIFs. Anisotropic porous structure was constructed with the help of microwave-assisted foaming strategy due to the directional growth of foam pores, which led to anisotropic mechanical and thermal insulation performance of resultant PIFs. PIFs demonstrated robust mechanical performance in the vertical direction (i.e., parallel to pore growth direction) and mechanical flexibility (compression response rate of 97.1–99.0 %) in the horizontal direction (i.e., perpendicular to the pore growth direction). The co-polymerized PIFs also presented excellent thermal insulation performance, with thermal conductivity ranging from 0.0266 to 0.0517 W/(m·K) within a temperature range of 25∼300 °C. In addition, PIFs exhibited exceptional thermal stability and flame retardancy performance, which demonstrate a great potential for high-temperature thermal protection applications. To summarize, multifunctional PIFs with excellent mechanical, thermal insulation and flame retardancy were successfully prepared by adopting co-polymerization strategy and microwave-assisted foaming technique, which have promising applications in high-end engineering sectors.

Numerical Investigation on Thermal Conductivity of Graphene Foam Composite for Thermal Management Applications.

Graphene foam prepared by the chemical vapor deposition method is a promising thermal interfacial material. However, the thermal properties of graphene foam highly depend on the experimental fabrication conditions during the chemical vapor deposition process. Aiming to reveal how to prepare the appropriate graphene foam for the various thermal management scenarios, the influence of experimental conditions on thermal properties of graphene foam was investigated. Furthermore, the contribution of thermal conductivity and thermal radiation to the effective thermal coefficient of graphene foam was carried out for comparison. The research results showed that the porosity and the cross-section shape of the struts of the growth template were two critical factors affecting the thermal transport of graphene foam, especially with the increase of temperature. In addition, the deposition time of graphene determined the wall thickness and affected the thermal conductivity directly. The thermal radiation contributed more than thermal conductivity when the temperature climbed continuously. Comparatively, the effective thermal coefficient of graphene foam composite with high porosity and circular-shape struts was much superior to that of others at high temperature. The research findings provide important guidance for graphene foam fabrication and its applications in the field of thermal management.

Analysis and Design of Engraving Machine Movement

CNC routers play a significant role in several markets such as furniture design, circuit board manufacturing, plastic and foam fabrication. It can allow to complete projects in few hours that used to take several days CNC routers can work on sheets of woods, plastic, rubber, acrylics, and non-ferrous metal and CNC router machine moves and cuts in three directions using computer aided design software.A computer program has been established to design the power screws of any engraving machine. The power required to cut material was calculated by the program. The resisting force was analyzed and all stresses act on the power screws. The power screws were designed by using the main common theory of failures. The buckling and maximum deflection was checked in this program.An example of the output results was designed and drawn in Advanced Centre of Technology using solid works software. The nut connected to the screws was also drawn. The parts of engraving machine have been manufactured and tested in Advanced Centre Technology A.C.T in Libya.

Activated carbon-reinforced polyurethane composite foams with hierarchical porosity for broadband sound absorption

The generation of various noise has caused severe noise pollution issues across a wide frequency spectrum, urgently requiring the development of sound-absorbing materials. Herein, we introduce composite polyurethane (PU) foams incorporating extremely nanoporous activated carbon (AC) including both meso- and macro-sized pores as an eco-friendly sound-absorbing material with superior and broadband sound absorption capabilities. The composite foam absorbs 95.8 % of the incident acoustic waves in the 2,000–5,000 Hz frequency range, i.e., the most sensitive range for the human auditory system, far outperforming pristine PU foam, which absorbs only 70.6 %. We demonstrate that sound absorption properties can be fine-tuned by adjusting the pore type and content of the AC. Significantly, the optimized composite foam structure absorbs 100 % of the incident waves at a specific frequency of 2,550 Hz. Collectively, we propose a master curve for the sound absorption properties derived from various composite foams, demonstrating that the properties can be precisely predictable and subsequently used for designing the pore characteristics and content of AC. Incorporating AC can also improve the mechanical properties of foams through interfacial adhesion phenomena. Our methodology provides valuable insights into the fabrication of composite foams with tunable sound absorption properties as a promising solution to noise pollution.

Hierarchical bio-inspired design and fabrication of all-dimensional superhydrophobic ultra-lightweight high-volume fly ash cement foams using novel ultrasonic-assisted siloxane-encapsulated pickering emulsions

Ultra-lightweight foamed cement (ULFC) exhibits super-high porosity and excellent thermal-insulation capabilities. However, the thermodynamic instability and high water-absorptivity of ULFC with high-volume fly ash have restricted its large-scale application. Superhydrophobic technology can significantly improve the substrates’ hydrophobicity, among which the nanocoating is a popular option but the water-repellent layer may be easily destroyed due to the mechanical damage. Therefore, the intrinsic superhydrophobization becomes a promising alternative to the coating scheme. Here, the internal superhydrophobic ULFC was formulated through introducing the ultrasonic-assisted siloxane-encapsulated Pickering emulsions, in which two Pickering structures containing n-dodecyltrimethoxysilane were stabilized by hydrophobic SiO2 and C–S–H nanoparticles, respectively. Compared with the SiO2 nanoparticles-stabilized dispersion, the droplets of C–S–H nanoparticles-stabilized Pickering emulsion were more stable and controlled-release in cement hydration environment. As such, the incorporation of the latter showed no negative impact on the setting times and static yield stress of the interstitial matrix, optimizing the homogeneity, mechanical strength and heat conductivity of ULFC. The combination of nanoscale foam stabilizer and Pickering emulsions could form the hierarchical waterproof structure with low surface free energy at the gas-solid interfaces, and the multiscale siloxane-grafted intertwined hydration products were responsible for the inner superhydrophobicity of ULFC. Therefore, under the water vapor-saturated environment, the water absorption of superhydrophobic samples showed only a slight increase as a function of time and the ULFC was still hydrophobic with a reduction of apparent water contact angle from 154.6° to 137.8°. From energy consumption analysis, the all-dimensional superhydrophobic ULFC had a potential application in heat-insulation building.

Scalable fabrication of collagen fiber-waterborne polyurethane foams with enhanced toughness and thermal insulation by constructing energy dissipation networks

Natural fiber-based foams demonstrate outstanding potential for energy-efficient building and personal protective equipment applications due to their lightweight, high porosity, and sustainability. However, the weak interfacial interaction among fibers, functional additives, and the matrix hampers effective stress dissipation, largely affecting the material performance. Herein, this paper demonstrates a facile strategy for fabricating high-performance collagen fiber-based foams by constructing efficient energy dissipation networks using tannin-modified leather collagen fibers (T-LCF) and waterborne polyurethane (WPU). Tannin acts as a coupling bridge, linking the fiber and polyurethane to create a hydrogen-bonded network, enhancing energy dissipation and imparting excellent mechanical properties. Compared to WPU foam (WPUF), the T-LCF-based foam (WPUF/T-LCF) showed 65%, 34 times, and 35% improvements in tensile strength, compressive strength, and ultimate oxygen index, respectively. This study provides new insights into the cleaner production of high-performance natural fiber-based foam composites and a new way for the high-value utilization of collagen solid waste.

Unlocking the enormous potential of biological materials: Polymer-assisted foam for enhanced oil recovery in fractured porous media

In natural fractured reservoirs, foam serves as an effective method for mobility control, leading to a significant enhancement in oil recovery. However, the harsh conditions of reservoirs present challenges to the strength and stability of foams. In this study, we conducted comprehensive experimental research, employing a combination and screening approach, to successfully develop a super foam using biomacromolecules (Welan gum) and bio-based surfactants (APG). Bulk foam tests were carried out and the performance of foam flooding in fractured porous media was evaluated. The results demonstrated that the introduction of Welan gum significantly increased the strength of the foam and improved its rheological properties. The Welan gum-enhanced foam (WG-foam) exhibited higher flow resistance in fractured reservoirs, resulting in enhanced oil recovery. Compared to traditional hydrophobically associating polymer-enhanced foam (HAPAM-foam), the WG-foam showed a remarkable half-life for drainage of 20 h, which is 13 times longer than that of HAPAM-foam. Furthermore, the ultimate oil recovery of WG-foam was 21% higher than that of HAPAM, reaching 87%. Through molecular dynamics simulations, we uncovered the exceptional water-binding capacity of Welan gum, which significantly delayed the drainage rate in the foam lamella, thus enhancing foam stability. This work not only provides a powerful technical approach for foam-enhanced oil recovery, but also offers new insights into the fabrication of high-performance foams.

ZSM-5@ceramic foam composite catalyst derived from spent bleaching clay for continuous pyrolysis of waste oil to produce monocyclic aromatic hydrocarbons

Spent bleaching clay, a solid waste generated during the refining process of vegetable oils, lacks an efficient treatment solution. In this study, spent bleaching clay was innovatively employed to fabricate ceramic foams. The thermal stability analysis, microstructure, and crystal phase composition of the ceramic foams were characterized by TG-DSC, SEM, and XRD. An investigation into the influence of Al2O3 content on the ceramic foams was conducted. Results showed that, as the Al2O3 content increased from 15 wt% to 30 wt%, there was a noticeable decrease in bulk density and linear shrinkage, accompanied by an increase in compressive strength. Additionally, the ceramic foams were used as catalyst supports, to synthesize ZSM-5@ceramic foam composite catalysts for pyrolysis of waste oil. The open pores of the ZSCF catalyst not only reduced diffusion path length but also facilitated the exposure of more acid sites, thereby increasing the utilization efficiency of ZSM-5 zeolite. This, in turn, engendered a significant enhancement in monocyclic aromatic hydrocarbons content from 39.15 % (ZSM-5 powder catalyst) to 78.96 %. Besides, a larger support pore size and a thicker ZSM-5 zeolite coating layer led to an increase in monocyclic aromatic hydrocarbons content. As the time on stream was extended to 56 min, the monocyclic aromatic hydrocarbon content obtained with the composite catalyst remained 12.41 % higher than that of the ZSM-5 powder catalyst. These findings validate the potential of the composite catalyst. In essence, this study advances the utilization of spent bleaching clay and introduces a novel concept for ceramic foam fabrication. Furthermore, it contributes to the scaling up of catalytic pyrolysis technology.

A new strategy to fabricate polyvinyl alcohol (PVA) foam with low thermal conductivity using PVA-citric acid solution in supercritical carbon dioxide

Polymer foams with low density have a great potential in the field of heat preservation due to good thermal insulation properties. In this work, a new method for the preparation of polyvinyl alcohol (PVA) foam with low density using PVA-citric acid (CA) solution based on supercritical carbon dioxide (scCO2) foaming technology was proposed. This approach introduced abundant water as co-blowing agent and utilized the crosslinking between CA and PVA to regulate the viscosity of solution, thereby the low density PVA foam with stable morphology was prepared. The effects of saturation time, PVA content, CA content, temperature and pressure on PVA foaming behavior were investigated. Meanwhile, the use of water as assistant solvent was explored to increase the co-blowing content and weaken the diffusion of water molecules to CO2 in the PVA-CA solution, which resulted in the successful fabrication of PVA foams with lower density and low thermal conductivity. The results showed that the minimum densities of PVA before and after addition of assistant solvent were 0.070 g/cm3 and 0.047 g/cm3, respectively. Moreover, PVA foam fabricated by the addition of assistant solvent showed the thermal conductivity of 29.68 mW/mK and the compression modulus of 2.21 MPa.

Numerical Simulation of Aluminum Foams by Space Holder Infiltration

AbstractThis study explores the simulation and analysis of the infiltration process for manufacturing A356 aluminum alloy foams using vacuum pressure. The infiltration technique, known for its versatility in liquid-state metal processing, is widely employed for metal foam production due to its ease of application. The study investigates the relationship between the geometric parameters of the preform, system pressure, and filling times, revealing a correlation. The simulation using the Flow 3D software determines the pressure and vacuum time required to achieve successful aluminum foam without filling failures. Experimental validation through infiltration casting using NaCl as a removable preform aligns with the simulated results, yielding high-quality aluminum foam samples with diverse pore sizes (0.5 mm, 1.0 mm, and 2.0 mm), uniform and interconnected pore distribution, average porosity percentages of 65%, and a relative density of 0.35. The research contributes insights into optimizing the infiltration process for aluminum foam fabrication, bridging the gap in limited literature on cellular metals.

Fabrication, Processing, Properties, and Applications of Closed-Cell Aluminum Foams: A Review.

Closed-cell aluminum foams have many excellent properties, such as low density, high specific strength, great energy absorption, good sound absorption, electromagnetic shielding, heat and flame insulation, etc. As a new kind of material, closed-cell aluminum foams have been used in lightweight structures, traffic collision protections, sound absorption walls, building decorations, and many other places. In this paper, the recent progress of closed-cell aluminum foams, on fabrication techniques, including the melt foaming method, gas injection foaming method, and powder metallurgy foaming method, and on processing techniques, including powder metallurgy foaming process, two-step foaming process, cast foaming process, gas injection foaming process, mold pressing process, and integral foaming process, are summarized. Properties and applications of closed-cell aluminum foams are discussed based on the mechanical properties and physical properties separately. Special focuses are made on the newly developed cast-forming process for complex 3D parts and the improvement of mechanical properties by the development of small pore size foam fabrication and modification of cell wall microstructures.