A vibration-damping energy-dissipating foam aluminum composite material and a preparation method thereof

Abstract

This invention discloses a vibration-damping and energy-dissipating foamed aluminum composite material and its preparation method, belonging to the field of metal matrix composite technology. The method involves surface pretreatment and vinyltriethoxysilane pore wall interface treatment of the open-cell foamed aluminum skeleton; a first component is prepared by combining high-purity, low-sulfur flake graphite, hydrophobic fumed silica, and vinyl-terminated polyorganosiloxane; a second component is prepared by combining an organohydrogen polysiloxane crosslinking agent containing Si-H bonds, a platinum catalyst, and a curing inhibitor; after degassing the two components, the mixture is introduced into the foamed aluminum pores through horizontal reciprocating vibration during static negative pressure exhaust and restoration to normal pressure, followed by curing and slow cooling to obtain the composite material. The beneficial effects of this invention are: improved pore filling continuity and interface bonding stability, reduced debonding and energy dissipation during cyclic compression, and improved compression energy absorption and cyclic vibration damping stability through viscoelastic deformation, micro-slippage of flake graphite, and pore wall constraint.

Description

Technical Field

[0001] This invention relates to the field of metal matrix composites, and in particular to a vibration-damping and energy-dissipating foamed aluminum composite material and its preparation method. Background Technology

[0002] Aluminum foam is a lightweight porous metallic material with a three-dimensional pore structure. It possesses characteristics such as low density, certain load-bearing capacity, compression energy absorption, and sound and vibration dissipation, making it valuable for applications in traffic protection, equipment cushioning, building vibration isolation, mechanical vibration reduction, and lightweight structural components. With increasing demands for comprehensive performance in engineering structures, including lightweight, load-bearing capacity, energy dissipation, and cyclic stability, single-layer aluminum foam materials are prone to problems such as localized pore wall collapse, residual deformation accumulation, and energy dissipation attenuation under repeated compression or vibration loads. Therefore, combining aluminum foam with polymer damping phases, viscoelastic phases, or sandwich structures has become an important technological direction for improving the service performance of aluminum foam materials.

[0003] In the prior art, there are already solutions for combining open-cell aluminum foam with viscoelastic damping materials. For example, CN105131485A discloses a composite material of aluminum foam and viscoelastic damping and its preparation method. It mainly involves immersing open-cell aluminum foam into an emulsion or premix of viscoelastic damping material, allowing it to penetrate into the internal pores of the aluminum foam and solidify to form a composite material. This solution focuses on lightweighting and damping performance, but its technical focus is on macroscopic immersion composite. It lacks more refined process control for gas discharge in the complex interconnected channels of open-cell aluminum foam, continuous filling of deep pores, stability of the filling phase distribution, and interface retention ability after cyclic compression. For example, CN103935080B discloses a polymer / aluminum foam integrated composite sandwich panel, which uses an aluminum foam core layer, a polymer / aluminum foam composite layer, and a polymer protective surface layer to form a multi-layer sandwich structure. This is mainly used to improve overall integrity and address the interface issues between the surface layer and the core layer. However, this type of sandwich composite structure focuses more on overall panel protection and interlayer bonding, and cannot fully solve problems such as the uniform entry of the filling phase into the three-dimensional channels of high-porosity open-cell aluminum foam, residual local voids within the pores, debonding of the filling phase during repeated compression, and attenuation of energy dissipation capacity. Especially in vibration damping and energy dissipation scenarios, if the filling phase relies solely on ordinary impregnation, static infiltration, or single negative pressure treatment, it is easily affected by factors such as pore tortuosity, residual gas, flow resistance, dispersion stability, and interface stress concentration. This leads to defects such as discontinuous filling, local collapse, interface loosening, and insufficient damping retention after cyclic loading, even if the material shows some reinforcement during initial compression.

[0004] Therefore, there is still a need in this field for a method to prepare vibration-damping and energy-dissipating composite materials suitable for open-cell aluminum foam. The key issues to address include the difficulty in ensuring the filler phase fully and uniformly enters the three-dimensional pores of the aluminum foam, the lack of effective constraint on the pore walls during compression, the attenuation of energy dissipation capacity after cyclic loading, and insufficient stability of the composite interface. This method should be able to improve the continuity of pore filling, compression energy absorption capacity, cyclic energy dissipation stability, and post-compression structural integrity without damaging the lightweight porous structure of the aluminum foam, thereby meeting the requirements for stable vibration-damping and energy-dissipating materials under repeated vibration and cyclic compression conditions. Summary of the Invention

[0005] The purpose of this invention is to provide a vibration-damping and energy-dissipating foamed aluminum composite material and its preparation method, so as to solve the problems in existing open-cell foamed aluminum composite materials where the filling phase is difficult to fully and uniformly enter the three-dimensional interconnected channels, local voids are easily generated in the pores, the pore wall constraint is insufficient during compression, and the interface stability and energy dissipation capacity are easily reduced after cyclic loading. Thus, the invention meets the technical requirements of open-cell foamed aluminum composite materials for filling continuity, compression energy absorption capacity, cyclic energy dissipation stability and structural integrity under repeated compression and vibration load conditions.

[0006] To achieve the above-mentioned objectives and address the aforementioned technical problems, this invention provides a method for preparing a vibration-damping and energy-dissipating foamed aluminum composite material, comprising the following steps: S1, perform surface pretreatment on the open-cell aluminum foam skeleton to obtain the pretreated skeleton; S2, the pretreated skeleton is treated with vinyltriethoxysilane treatment solution to obtain a skeleton with a vinylsilane interface layer. S3, Preparation of the first component: High-purity, low-sulfur flake graphite and hydrophobic fumed silica are added to vinyl-terminated polyorganosiloxane for pre-dispersion to obtain the first component; S4, Preparation of the second component: Mix the organohydrogen polysiloxane crosslinking agent containing Si-H bonds, the platinum catalyst and the curing inhibitor to obtain the second component; S5, mix the first component and the second component immediately before use and degas to obtain a damping filling liquid; S6, place the skeleton obtained in S2 into the mold and add the damping filling liquid. First, perform static negative pressure venting, and then apply horizontal reciprocating vibration synchronously during the restoration of normal pressure to allow the damping filling liquid to enter the skeleton channel. S7. The impregnated sample is cured, and after curing, it is slowly cooled and demolded to obtain a vibration-damping and energy-dissipating foam aluminum composite material.

[0007] Preferably, the pore size of the perforated aluminum foam frame is 3-6 mm, and the porosity is 70%-88%.

[0008] Preferably, in S1, the surface pretreatment includes sequentially performing cleaning, alkaline washing, acid washing, and water washing.

[0009] Preferably, the alkaline washing is performed by treating with 0.3-0.8 wt% NaOH solution for 30-60 seconds, the acid washing is performed by treating with 5-15 wt% dilute nitric acid for 10-30 seconds, and the water washing is performed by ultrasonic cleaning with deionized water for multiple water changes until the pH of the immersion solution is 6.5-7.5.

[0010] Preferably, in S2, the vinyltriethoxysilane treatment solution has a vinyltriethoxysilane mass concentration of 0.3-0.8 wt%, the solvent is a mixed solvent of ethanol / water with a volume ratio of 95:5, the vinyltriethoxysilane treatment solution is adjusted to pH 4.0-4.8 with glacial acetic acid, and hydrolyzed for 20-30 min before use.

[0011] Preferably, in S2, the pore wall interface treatment includes: immersing the pretreated skeleton in a vinyltriethoxysilane treatment solution, evacuating it to -0.02MPa to -0.05MPa in a sealed container, closing the evacuation valve and maintaining this for 1-3 minutes, removing it, centrifuging it at 300-800rpm for 30-90s to remove residual droplets in the pores, and then heat-treating it at 100-110℃ for 30-60 minutes to obtain a skeleton with a vinylsilane interface layer.

[0012] Preferably, in S3, based on 100 parts by weight of vinyl-terminated polyorganosiloxane, the high-purity, low-sulfur flake graphite is 3-6 parts by weight, and the hydrophobic fumed silica is 0.5-1.5 parts by weight. Preferably, the vinyl-terminated polyorganosiloxane is vinyl-terminated polydimethylsiloxane with a viscosity of 1000-3000 mPa·s and a vinyl content of 0.05-0.20 mmol / g; the high-purity, low-sulfur flake graphite has a particle size of 10-25 μm, a carbon content of not less than 99.5 wt%, and a sulfur content of not more than 100 ppm; the hydrophobic fumed silica is fumed silica surface-modified with hexamethyldisilazane and has a specific surface area of ​​100-250 m² / g. 2 / g.

[0013] Preferably, in S3, the high-purity, low-sulfur flake graphite and hydrophobic fumed silica are dried at 80-120°C for 1-3 hours before the addition of vinyl-terminated polyorganosiloxane.

[0014] Preferably, the pre-dispersion speed is 1500-2500 rpm, the pre-dispersion time is 10-20 min, and the material temperature is controlled at 18-25℃ by a water-cooled jacket during the pre-dispersion process.

[0015] Preferably, in S4, based on 100 parts by weight of the vinyl-terminated polysiloxane in S3, the organohydrogen polysiloxane crosslinking agent containing Si-H bonds is 3-10 parts by weight, and the curing inhibitor is 0.01-0.05 parts by weight.

[0016] Preferably, the platinum content in the platinum catalyst is 5-50 ppm, based on the total mass of the damping filling liquid formed after mixing the first and second components.

[0017] Preferably, the second component further includes 0-30 parts by weight of dimethyl silicone oil diluent.

[0018] Preferably, the organohydrogen polysiloxane crosslinking agent containing Si-H bonds is hydrogen-containing polydimethylsiloxane, methyl hydrogen-containing silicone oil, or organohydrogen polysiloxane, and the Si-H content is 0.10-0.50 wt%.

[0019] Preferably, the platinum catalyst is a Karstedt-type platinum catalyst or a platinum-divinyltetramethyldisiloxane complex; preferably, the curing inhibitor is an ethynylcyclohexanol inhibitor or an ethynol inhibitor.

[0020] Preferably, in S5, the molar ratio of Si-H groups to vinyl groups in the system after mixing the first component and the second component is 1.02-1.12:1, and degassing is performed at -0.08MPa to -0.095MPa for 3-5 minutes.

[0021] Preferably, the time from mixing the first component and the second component to the completion of the impregnation does not exceed 30 minutes.

[0022] Preferably, in S6, the vacuum degree of the static negative pressure exhaust is -0.07MPa to -0.09MPa, the holding time is 2-3min, the frequency of the horizontal reciprocating vibration is 30-60Hz, the amplitude is 0.2-0.6mm, and it continues until 30-60s after the pressure is completely restored to normal, so that the damping filling liquid enters the skeleton channel.

[0023] Preferably, in S7, the curing conditions are 80-100℃ for 2-4 hours, and after curing, the material is slowly cooled to below 40℃ in the furnace before demolding to obtain a vibration-damping and energy-consuming foam aluminum composite material.

[0024] This application also provides a vibration-damping and energy-dissipating foamed aluminum composite material, which is prepared by the above-described preparation method.

[0025] The beneficial effects of the technical solution provided by this invention are as follows: By combining static negative pressure exhaust with horizontal reciprocating vibration during the restoration of normal pressure, the gas trapped in the foamed aluminum channels can be discharged first. Then, external pressure restoration and vibration disturbance can be used to promote the damping filling liquid to enter the complex interconnected pores, reduce local unfilled areas, and make the filling phase form a more continuous distribution structure in the three-dimensional channels.

[0026] After the silicone rubber cured phase fills the pores of aluminum foam, it can provide support and constraint to the metal pore walls, thus slowing down the local collapse of the pore walls during compression. The flake graphite dispersed in the silicone rubber phase can generate interlayer micro-slippage, interfacial friction and shear energy dissipation when deformed under pressure, so that the composite material exhibits better compression energy absorption characteristics in terms of plateau stress and energy absorption per unit volume.

[0027] Hydrophobic fumed silica dispersed in vinyl-terminated polyorganosiloxane can improve the thixotropic stability of the filling system, reduce the tendency of flake graphite to settle and locally agglomerate, and enable the damping filler to maintain a relatively stable dispersion state during wetting and curing, thereby facilitating the formation of a uniform silicone rubber-flake graphite composite filler phase.

[0028] After the vinyl silane interface layer is set on the surface of the aluminum foam pore wall, it can enhance the interfacial bonding between the silicone rubber filler phase and the metal skeleton, and reduce the risk of filler phase debonding, cracking and energy dissipation decay during cyclic compression. At the same time, slow cooling after curing helps to release the residual stress at the interface, so that the composite material can still maintain a high energy retention rate and equivalent damping ratio after multiple cyclic loading. Attached Figure Description

[0029] Figure 1 This is a diagram showing the filling of the aluminum foam composite material in the embodiments and comparative examples of the present invention. Among them, (a) is Example 1, (b) is Comparative Example 3, and (c) is Comparative Example 5.

[0030] Figure 2 These are morphological images of the aluminum foam of the present invention and the composite material of Example 1 before and after monotonic compression; Among them, (a) is the aluminum foam before deformation, (b) is the aluminum foam after monotonic compression, (c) is the composite material of Example 1 before deformation, and (d) is the composite material of Example 1 after monotonic compression.

[0031] Figure 3 The images show the final deformation of the aluminum foam and the composite material of Example 1 after cyclic compression at different compressive strain amplitudes. Wherein, (a) represents aluminum foam and (d) represents the morphology of Example 1 after cyclic compression at a 10% compressive strain amplitude. (b) shows the morphology of aluminum foam and (e) shows the morphology of Example 1 after cyclic compression at a 20% compressive strain amplitude. (c) shows the morphology of aluminum foam and (f) shows the morphology of Example 1 after cyclic compression at a 30% compressive strain amplitude. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. Of course, the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0033] Example 1 This embodiment provides a method for preparing a vibration-damping and energy-dissipating foamed aluminum composite material, which specifically includes the following steps.

[0034] S1. Surface pretreatment of open-cell aluminum foam skeleton An open-cell aluminum foam skeleton was selected as the three-dimensional support skeleton. The average pore diameter of the open-cell aluminum foam skeleton is 4 mm and the porosity is 82%.

[0035] The open-cell aluminum foam skeleton is sequentially cleaned, alkaline washed, acidic washed, and water washed to obtain a pretreated skeleton, specifically as follows: First, the open-cell aluminum foam skeleton was ultrasonically cleaned with ethanol to remove oil and cutting residue from its surface; then it was rinsed with deionized water. Next, the cleaned open-cell aluminum foam skeleton was placed in a 0.5 wt% NaOH solution for 45 seconds for alkaline washing, and immediately rinsed with deionized water after removal.

[0036] The alkaline-washed open-cell aluminum foam skeleton is then placed in a 10wt% dilute nitric acid solution for 20 seconds to remove any loose oxide layer or insoluble deposits that may remain on the pore surface after alkaline washing. After acid washing, the open-cell aluminum foam skeleton is ultrasonically cleaned with deionized water with multiple water changes until the pH of the immersion solution reaches 7.0, resulting in a pretreated skeleton.

[0037] S2, Hole wall interface treatment Preparation of vinyltriethoxysilane treatment solution: Add vinyltriethoxysilane to a mixed solvent of ethanol and water in a volume ratio of 95:5 to make the mass concentration of vinyltriethoxysilane 0.5wt%; adjust the pH of the system to 4.5 with glacial acetic acid, and pre-hydrolyze vinyltriethoxysilane in the mixed solvent for 25 min to obtain vinyltriethoxysilane treatment solution.

[0038] The pretreated skeleton obtained in S1 is immersed in the above vinyltriethoxysilane treatment solution and placed in a sealed container; the sealed container is evacuated to -0.03MPa and the evacuation valve is closed and kept for 2 minutes to allow the vinyltriethoxysilane treatment solution to enter the pores of the open-cell aluminum foam skeleton.

[0039] After processing, the skeleton was removed and centrifuged at 500 rpm for 60 seconds to remove residual droplets in the pores; then it was placed in an oven and heat-treated at 105℃ for 45 minutes to obtain a skeleton with a vinyl silane interface layer.

[0040] S3, Preparation of the first component Vinyl-terminated polydimethylsiloxane was selected as the matrix. The viscosity of the vinyl-terminated polydimethylsiloxane was 2000 mPa·s and the vinyl content was 0.12 mmol / g, based on 100 parts by weight.

[0041] High-purity, low-sulfur flake graphite is selected as the sheet-like energy-consuming filler. The high-purity, low-sulfur flake graphite has a D50 particle size of 18μm, a carbon content of not less than 99.5wt%, and a sulfur content of not more than 100ppm.

[0042] Hydrophobic fumed silica modified with hexamethyldisilazane was selected as a thixotropic filler, and the specific surface area of ​​the hydrophobic fumed silica was 180 m² / g.

[0043] Before adding vinyl-terminated polydimethylsiloxane, the high-purity, low-sulfur flake graphite and hydrophobic fumed silica are dried at 100°C for 2 hours.

[0044] Subsequently, 4 parts by weight of high-purity, low-sulfur flake graphite and 1.0 part by weight of hydrophobic fumed silica were added to 100 parts by weight of vinyl-terminated polydimethylsiloxane and pre-dispersed using a water-cooled jacket temperature control method. The pre-dispersion speed was 2000 rpm, the pre-dispersion time was 15 min, and the material temperature was controlled at 22℃ during the pre-dispersion process to obtain the first component.

[0045] S4, Preparation of the second component Based on 100 parts by weight of vinyl-terminated polydimethylsiloxane in S3, hydrogen-containing polydimethylsiloxane is selected as the crosslinking agent of organohydrogen polysiloxane containing Si-H bonds, and its Si-H content is 0.25 wt%.

[0046] Six parts by weight of hydrogen-containing polydimethylsiloxane, a curing inhibitor, and a platinum catalyst were mixed to obtain the second component.

[0047] The curing inhibitor is 1-ethynyl-1-cyclohexanol, and the dosage is 0.02 parts by weight. The platinum catalyst is a platinum-divinyltetramethyldisiloxane complex solution, and the platinum content in the platinum catalyst is 20 ppm based on the total mass of the damping filling liquid formed after the first and second components are mixed.

[0048] S5. Preparation of damping filling fluid The first component obtained in S3 and the second component obtained in S4 were mixed immediately to make the molar ratio of Si-H groups to vinyl groups in the mixed system 1.06:1.

[0049] After mixing, the system was placed in a vacuum degassing device and degassed at -0.09 MPa for 4 min to obtain the damping filling liquid.

[0050] The time from mixing the first component and the second component to completing the subsequent impregnation treatment is controlled within 20 minutes.

[0051] S6, wetting of damping filler fluid The skeleton with a vinyl silane interface layer obtained in S2 is placed in a mold, and the damping filling liquid obtained in S5 is added to the mold so that the damping filling liquid covers and contacts the pores of the open-cell aluminum foam skeleton.

[0052] Then, static negative pressure exhaust is performed first. The vacuum degree of static negative pressure exhaust is -0.085MPa, and the holding time is 2.5min.

[0053] After the static negative pressure exhaust is completed, the pressure is restored to normal. During the restoration process, a horizontal reciprocating vibration is applied simultaneously, with a frequency of 45 Hz and an amplitude of 0.45 mm. After restoring to normal pressure, the horizontal reciprocating vibration continues for 45 seconds to allow the damping filling fluid to enter the skeleton channels.

[0054] S7, Curing, Cooling and Demolding After the impregnation treatment is completed, the sample and mold are placed in an oven and cured at 90°C for 3 hours.

[0055] After curing, turn off the oven and allow the sample to cool slowly with the oven. When the sample temperature cools to below 40°C, demold to obtain vibration-damping and energy-dissipating foam aluminum composite material.

[0056] Example 2 Vibration-damping and energy-dissipating foamed aluminum composite materials were prepared using the same method as in Example 1, with the following differences: In S3, based on 100 parts by weight of vinyl-terminated polydimethylsiloxane, the amount of high-purity, low-sulfur flake graphite is 3 parts by weight, and the amount of hydrophobic fumed silica is 0.5 parts by weight.

[0057] Example 3 Vibration-damping and energy-dissipating foamed aluminum composite materials were prepared using the same method as in Example 1, with the following differences: In S3, based on 100 parts by weight of vinyl-terminated polydimethylsiloxane, the amount of high-purity, low-sulfur flake graphite is 6 parts by weight, and the amount of hydrophobic fumed silica is 1.5 parts by weight.

[0058] Example 4 Vibration-damping and energy-dissipating foamed aluminum composite materials were prepared using the same method as in Example 1, with the following differences: In S1, an open-cell aluminum foam skeleton with an average pore size of 6 mm and a porosity of 70% is selected.

[0059] Example 5 Vibration-damping and energy-dissipating foamed aluminum composite materials were prepared using the same method as in Example 1, with the following differences: In S2, the mass concentration of vinyltriethoxysilane in the vinyltriethoxysilane treatment solution is 0.8 wt%. The pH of the system is adjusted to 4.0 using glacial acetic acid, and the vinyltriethoxysilane is pre-hydrolyzed in the mixed solvent for 30 min.

[0060] Example 6 Vibration-damping and energy-dissipating foamed aluminum composite materials were prepared using the same method as in Example 1, with the following differences: In S6, the vacuum degree of static negative pressure exhaust is -0.07MPa, and the holding time is 3min; during the restoration of normal pressure, horizontal reciprocating vibration is applied simultaneously with a vibration frequency of 30Hz and an amplitude of 0.2mm, and vibration continues for 60s after the pressure is restored to normal.

[0061] Comparative Example 1 Aluminum foam composite material was prepared using the same method as in Example 1, with the following difference: In S2, the pretreated skeleton is not treated with vinyltriethoxysilane solution to treat the pore wall interface; the pretreated skeleton obtained in S1 is dried and then directly used for impregnation with damping filling solution in S6.

[0062] Comparative Example 2 Aluminum foam composite material was prepared using the same method as in Example 1, with the following difference: In S3, without adding high-purity, low-sulfur flake graphite, only 1.0 part by weight of hydrophobic fumed silica is added to 100 parts by weight of vinyl-terminated polydimethylsiloxane for pre-dispersion to obtain the first component.

[0063] Comparative Example 3 Aluminum foam composite material was prepared using the same method as in Example 1, with the following difference: In S3, without adding hydrophobic fumed silica, only 4 parts by weight of high-purity, low-sulfur flake graphite are added to 100 parts by weight of vinyl-terminated polydimethylsiloxane for pre-dispersion to obtain the first component.

[0064] Comparative Example 4 Aluminum foam composite material was prepared using the same method as in Example 1, with the following difference: In S3, the high-purity, low-sulfur flake graphite in Example 1 is replaced with ordinary industrial-grade flake graphite, wherein the D50 particle size of the ordinary industrial-grade flake graphite is 18 μm, and the addition amount is still 4 parts by weight.

[0065] Comparative Example 5 Aluminum foam composite material was prepared using the same method as in Example 1, with the following difference: In S6, after the static negative pressure exhaust is completed, horizontal reciprocating vibration is not applied during the restoration of normal pressure. Instead, the pressure is directly restored to normal and left to stand, so that the damping filling liquid enters the open-cell aluminum foam skeleton channel without horizontal reciprocating vibration.

[0066] Comparative Example 6 Aluminum foam composite material was prepared using the same method as in Example 1, with the following difference: In S7, after curing, the sample and mold are taken directly out of the oven and allowed to cool naturally to below 40°C at room temperature before demolding.

[0067] Experimental test: 1. Fill rate test The surface-treated open-cell aluminum foam skeleton was dried to constant weight and its mass was recorded as m0. After impregnation, curing, cooling, and demolding with the damping filler liquid according to the corresponding embodiment or comparative example, the residual filler on the sample surface was removed, and the mass of the composite material was recorded as m1. The mass of the filler phase was calculated based on the mass difference before and after filling, and the filling rate was calculated by combining the filler phase density, the external volume of the open-cell aluminum foam skeleton, and the porosity. The calculation formula is as follows: Filled phase mass: m = m1 – m0 Filled phase volume: V1 = m / ρ Theoretical pore volume: V0 = V × P Fill rate: η = V1 / V0 × 100% Where ρ is the density of the filled phase after curing, V is the total volume of the sample, and P is the porosity of the open-cell aluminum foam skeleton.

[0068] 2. Monotonic Compression Test Uniaxial compression tests were performed on the samples obtained in the examples and comparative examples using an electronic universal testing machine. During the test, the sample was placed between upper and lower compression plates and subjected to quasi-static compression along the sample height direction. The load-displacement curves were recorded, and the stress-strain curves were calculated based on the initial cross-sectional area and initial height of the sample.

[0069] The initial compressive modulus, plateau stress, peak stress, and energy absorbed per unit volume are calculated based on the stress-strain curve. The energy absorbed per unit volume is obtained by integrating the stress-strain curve over a defined compressive strain range.

[0070] 3. Cyclic compression hysteresis test Cyclic compression tests were performed on the samples using a material testing machine equipped with cyclic loading function. The test adopted a displacement control method, performing loading-unloading cycles along the sample height direction, and conducted the test at a compression strain amplitude of 30%, with each compression strain amplitude being cycled 10 times; and a cyclic stability test was performed at a selected compression strain amplitude for 50 cycles.

[0071] During the test, the load-displacement curve for each cycle was recorded, and the stress-strain hysteresis curve was calculated. The energy dissipation per cycle was calculated from the hysteresis loop area, and the energy retention rate was calculated based on the energy dissipation per cycle for different numbers of cycles.

[0072] The formula for calculating energy retention rate is: R = W n / W1× 100% Where W1 is the energy consumed in the first lap, W n This represents the energy consumed in a single lap of the nth lap.

[0073] 4. Calculation of equivalent damping ratio The equivalent damping ratio is calculated based on the cyclic compression hysteresis curve. The energy consumed per revolution (W) is also calculated. d The hysteresis loop area; maximum elastic energy storage W s Calculated based on the maximum load and maximum displacement of this cycle: W s = 1 / 2 × Fmax × δmax The equivalent damping ratio is calculated using the following formula: ξeq = W d / (4πW s ) Where Fmax is the maximum load of the cycle and δmax is the maximum displacement of the cycle.

[0074] Table 1. Test results of filling effect and compressive energy absorption performance

[0075] As shown in Table 1, the filling rate, elastic modulus, plateau stress, and energy absorption per unit volume of the example group were generally higher than those of the blank aluminum foam and the comparative example group. This indicates that the silicone rubber-sheet graphite-hydrophobic fumed silica composite filler phase can enter the pores of the aluminum foam and work together with the metal skeleton to bear and dissipate energy. In the comparative example, the lack of sheet graphite and hydrophobic fumed silica, or the horizontal reciprocating vibration, resulted in a decrease in both the filling effect and the compression energy absorption performance. This indicates that the above components and processes have a direct effect on improving the filling uniformity and compression energy absorption capacity.

[0076] Table 2 Results of Cyclic Energy Dissipation and Damping Stability Tests

[0077] As shown in Table 2, the example group exhibits higher single-cycle energy consumption, energy retention rate, and equivalent damping ratio during cyclic compression, indicating that the composite material of the present invention possesses good cyclic energy consumption and damping stability. In the comparative examples, the lack of a silane interface layer, flake graphite, hydrophobic fumed silica, horizontal reciprocating vibration, or slow cooling resulted in a decrease in cyclic energy retention capacity, indicating that interfacial bonding, filler slippage energy consumption, filler stability, and stress release process collectively affect the material's cyclic vibration damping performance.

[0078] Depend on Figure 1 It can be seen that the cross-sectional filling in Example 1 is more continuous and uniform; in Comparative Examples 3 and 5, there are obvious uneven filling or local unfilled areas. This indicates that hydrophobic fumed silica and horizontal reciprocating vibration help the damping filling liquid to be uniformly distributed within the pores of the aluminum foam. Figure 2 It can be seen that the blank aluminum foam collapses and breaks more significantly after compression, while the composite material of Example 1 retains a relatively intact block structure after compression. This indicates that the filler has a supporting and constraining effect on the pore walls of the aluminum foam, which can improve the structural integrity after monotonic compression. Figure 3 It can be seen that as the cyclic compression amplitude increases, the deformation and crushing degree of blank aluminum foam significantly intensifies; the composite material in Example 1 still maintains a good overall morphology under different amplitudes. This indicates that the composite filling structure of the present invention can share the deformation of the pore walls and dissipate the cyclic load energy, thereby improving the material's resistance to deformation and cyclic vibration reduction stability.

[0079] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a vibration-damping and energy-dissipating type of foam aluminum composite material, characterized by, Includes the following steps: S1, perform surface pretreatment on the open-cell aluminum foam skeleton to obtain the pretreated skeleton; S2, the pretreated skeleton is treated with vinyltriethoxysilane treatment solution to obtain a skeleton with a vinylsilane interface layer. S3, Preparation of the first component: High-purity, low-sulfur flake graphite and hydrophobic fumed silica are added to vinyl-terminated polyorganosiloxane for pre-dispersion to obtain the first component; S4, Preparation of the second component: Mix the organohydrogen polysiloxane crosslinking agent containing Si-H bonds, the platinum catalyst and the curing inhibitor to obtain the second component; S5, mix the first component and the second component immediately before use and degas to obtain a damping filling liquid; S6, place the skeleton obtained in S2 into the mold and add the damping filling liquid. First, perform static negative pressure venting, and then apply horizontal reciprocating vibration synchronously during the restoration of normal pressure to allow the damping filling liquid to enter the skeleton channel. S7. The impregnated sample is cured, and after curing, it is slowly cooled and demolded to obtain a vibration-damping and energy-dissipating foam aluminum composite material.

2. The production method according to claim 1, characterized by, The pore size of the open-cell aluminum foam skeleton is 3-6 mm, and the porosity is 70%-88%.

3. The production method according to claim 1, characterized by, In S1, the surface pretreatment includes sequential cleaning, alkaline washing, acid washing, and water washing; the water washing uses deionized water for multiple water changes and ultrasonic cleaning until the pH of the immersion solution is 6.5-7.

5.

4. The method of claim 1, wherein, In S2, the vinyltriethoxysilane treatment solution has a vinyltriethoxysilane concentration of 0.3-0.8 wt% and a pH of 4.0-4.

8.

5. The preparation method according to claim 4, characterized in that, In S2, the pore wall interface treatment includes: immersing the pretreated skeleton in a vinyltriethoxysilane treatment solution, maintaining it under negative pressure in a sealed container, removing it to remove residual droplets in the pores, and then performing heat treatment; the removal of residual droplets in the pores is achieved by centrifugal drying.

6. The method of claim 1, wherein, In S3, based on 100 parts by weight of vinyl-terminated polyorganosiloxane, the high-purity, low-sulfur flake graphite is 3-6 parts by weight, and the hydrophobic fumed silica is 0.5-1.5 parts by weight.

7. The preparation method according to claim 6, characterized in that, The vinyl-terminated polyorganosiloxane is vinyl-terminated polydimethylsiloxane; the high-purity, low-sulfur flake graphite has a carbon content of not less than 99.5 wt% and a sulfur content of not more than 100 ppm; the hydrophobic fumed silica is fumed silica that has been surface-modified with hexamethyldisilazane.

8. The method of claim 1, wherein, In S4, based on 100 parts by weight of the vinyl-terminated polysiloxane in S3, the Si-H bond-containing organohydrogen polysiloxane crosslinking agent is 3-10 parts by weight, and the curing inhibitor is 0.01-0.05 parts by weight.

9. The preparation method according to claim 8, characterized in that, The Si-H bond-containing organohydrogen polysiloxane crosslinking agent is a hydrogen-containing polydimethylsiloxane, methyl hydrogen-containing silicone oil, or an organohydrogen polysiloxane; the platinum catalyst is a Karstedt type platinum catalyst; The curing inhibitor is an ethynylcyclohexanol inhibitor or an ethynol inhibitor; In S5, the molar ratio of Si-H groups to vinyl groups in the system after mixing the first and second components is 1.02-1.12:1, and the platinum content in the platinum catalyst is 5-50 ppm.

10. A vibration-damping and energy-dissipating foam aluminum composite material, characterized by comprising: It is prepared by the preparation method according to any one of claims 1-9.

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