Single Aluminum Research Articles

Processing of Single Crystal Aluminum Using Compacted Alumina Powder

This experiment was designed to produce single crystal aluminum specimens through the understanding of solidification and processing parameter effects. In order to conduct the experiment, specimens were prepared by steel die casting and machining. After aluminum specimens were machined and ground, they were placed in the center of a crucible. Alumina powder was then filled and compacted in the crucible. The crucible was placed in a furnace for the remelting process. Finally, it was placed on a heat sink and was allowed to solidify. The powder compacting methods and remelting temperature were the two most important processing parameters. They were modified to improve the test and create single crystal microstructure. It was found that the compacting methods significantly affected the formation of leak within the crucible. Extremely dense powder results in crack openings; extremely loose powder results in formation of branch-like leakages. Uniformly and gently compacted powder will optimize the result. Remelting temperature affects the amount of thermal expansion. High temperature results in large amount of expansion,and causes cracks in the powder. Low temperature requires much more time and it cannot be guaranteed that the specimen is completely melted. The grain size and microstructure of each trial was compared and analyzed. Necessary modification of procedure was also made to improve future results. Finally in the report, the processing parameters and the resulting microstructure were correlated and discussed.

Scratch-resistant antireflective coating for mid-wave infrared band

In the 3–5 μm mid-wave infrared (MWIR) atmospheric transparency window region, infrared detectors are widely applied in spectral imaging, remote sensing and other fields, and their rapid development has put forward higher requirements for infrared optical windows. Common mid-wave infrared optical materials such as germanium and zinc sulfide have poor mechanical properties, causing them difficult to meet various harsh environments. In this paper, a 3-layer film stack is proposed to achieve high transmission and high hardness by radio-frequency reactive magnetron sputtering with the single aluminum target. Two types of AlN/Al2O3/AlN stack with top AlN thicknesses of 50 and 100 nm are studied to realize the best optical and mechanical characteristics. The average transmission increases up to 94.0% for 3–5 μm with the double-side AlN/Al2O3/AlN stacks on the silicon substrate, while the hardness is significantly improved to ∼16.6 GPa for both types. After annealing at 500 °C and 750 °C for 6 h in a vacuum environment, the spectra of the two film stacks move towards the shorter wavelength slightly, and the hardness of both are obviously enhanced. The highest hardness of the film system reaches ∼20.8 GPa, making it far more resistant to sand erosion than ordinary antireflection films. The result shows that this film stack can withstand high temperature and gravel impact tests, meeting the service requirements of the harsh environment of the MWIR optical system.

Micro-scale fracture toughness of textured alumina ceramics

Enhanced fracture resistance of textured alumina is ascribed to crack deflection along grain boundaries. In this work, we quantify and compare the micro-scale fracture toughness of textured alumina grains and grain boundaries by micro-bending tests. Notched micro-cantilevers were milled from single alumina textured grains (perpendicular to the [0001] direction) and across several textured grains (along the [0001] direction), using a focused ion beam technique. Bending tests were performed with a nanoindenter. A shape function for notched pentagonal-shaped cantilevers was developed using finite element analysis. The critical stress intensity factor at the notch tip was determined based on the measured fracture loads. The micro-scale fracture toughness of the textured alumina grain boundaries (2.3 ± 0.2 MPa m1/2) was about 30% lower than that of the grains (3.3 ± 0.2 MPa m1/2). These findings at the micro-scale are paramount for understanding the macroscopic fracture behaviour of textured alumina ceramics.

Experimental and numerical investigation of aluminum particle combustion driven instability in solid rocket motors

Aluminum particles are extensively employed to enhance the energetic properties of propellants. However, the heat release rate (HRR) fluctuations resulting from aluminum combustion can potentially affect the stability of solid rocket motors (SRMs). Using a self-made high-pressure combustion diagnostics system and laser ignition system, this work investigates the combustion behavior of single aluminum particle under propellant atmosphere and acoustic excitation. An unsteady aluminum combustion model using Ranz-Marshall correlation and involving the heat and mass transfer equation was developed. The D2 law of aluminum particle combustion in a real propellant under 0.5 MPa was fitted as t = D2/0.31. The measured combustion rate of laser-ignited aluminum particles was found to increase from 0.381mm2/s to 0.465 mm2/s when an acoustic excitation of sine wave(200 Hz, 20Pa) was applied to the propellant, which agreed well with the prediction of the proposed unsteady combustion model whose error was 4.7%. Then, the verified correlation was included in the SRM to calculate the HRR fluctuation of the aluminum on acoustic boundary near the propellant burning surface. The effects of particle diameter, gas velocity, oscillation amplitude and frequency on the HRR fluctuation were obtained. It was found that the HRR fluctuation increases with the increasing particle diameter, gas velocity, and oscillation amplitude, and that due to the acoustic boundary effect, the HRR fluctuation is more sensitive under low-frequency oscillation. Based on the HRR fluctuation of aluminum combustion and particle damping, the growth rate of instability resulting from aluminum combustion in an SRM was investigated. The results showed that the growth rate of instability resulting from aluminum combustion were 9.38s-1 and 24.06s-1, while the particle damping (−25.8s-1) caused by combustion residuals, which suggests the aluminum particles play a critical role in SRMs combustion instability.

Effect of particle size on ignition and oxidation of single aluminum: molecular dynamics study

Alumina nanoparticle is one of the attractive nanoparticles synthesized by the plasma method. The oxidation step in this method is challenging to explain experimentally. This work was to perform a molecular dynamics simulation to determine the oxidation mechanism of aluminum nanoparticles with different sizes and oxidation levels in the oxide layer. This work was to perform a molecular dynamics simulation to determine the oxidation mechanism of aluminum nanoparticles with different sizes and oxidation levels in the oxide layer. The simulation method employed the ReaxFF potential. The material used is aluminum nanoparticles in three different sizes (8, 12, and 16 nm) with an oxide layer thickness of 0.5 nm. Aluminum nanoparticles were given a relaxation treatment of 300 K for 1 ps and then heated to a temperature of 3250 K with a heating rate of 5×1013 K/s and cooled to 300 K. The ensemble used is a canonical ensemble with the Nose/Hoover thermostat method. The result shows that the higher the temperature applied to the system, the more oxygen molecules adsorption occurs on the surface of the oxide layer and the diffusion of oxygen to the particle core. The higher temperature applied also causes gaps, or void spaces, between the core and the shell. The reaction barrier for diffusion of oxygen also decreased significantly due to void space, and the surface of the aluminum core dissociates to the surface (alumina shell). Particles with a smaller size have a shorter ignition delay time. In addition, the smaller the particle size, the more oxygen molecules' reacted with aluminum particles in the particle core

Protection performance of sacrificial cladding with foam concrete filled aluminum tubes under blast loading

In the present study, a new sacrificial cladding with the core of foam concrete filled aluminum tube is proposed for structural protection to resist the blast load. First of all, the energy absorption capacity of a single aluminum tube filled with different densities of foam concrete and the cladding with the core of different densities of foam concrete filled aluminum tubes is experimentally investigated by the quasi-static compressive test. Then the blast test was conducted on the proposed cladding to experimentally examine its protective performance. In addition, with the validated numerical model by the blast test data, the effect of the density of foam concrete filler, the thickness of the aluminum tube, and the tube spacing on the protective performance of the cladding is numerically investigated. The quasi-static compressive test results show that the density of the foam concrete filler and the mutual squeezing between the tubes have a significant influence on the energy absorption capacity of the proposed cladding. The observed residual deflection of the rear panel in the blast test demonstrates that the protective performance of the proposed cladding could be significantly improved with increasing density of foam concrete filler. The numerical results show that increasing the density of foam concrete filler and the thickness of aluminum tube, reducing the tube spacing are beneficial to reduce the energy input to the system. Meanwhile, the simultaneously increased stiffness of the cladding would lead to a significant increase in the peak load transferred to the protected structure.

Numerical study of the impact and aggregation characteristics of alumina droplets on a wall in the solid rocket motor

The impact and aggregation of multiple alumina droplets on the inner wall of the solid rocket motor may generate a larger rebound aggregated droplet or adhere to the wall to form a liquid film. The rebound and adhesion characteristics of the aggregated droplet are of great significance for slag deposition and two-phase flow prediction in the motor. In this paper, the VOF (Volume of fluid) method is used to study the impact and aggregation process of multiple alumina droplets on the wall. Detailed numerical verifications are carried out, including the impact and aggregation of moving droplets, the aggregation and rebound of stationary droplets and the impact process of a single alumina droplet on the wall. It is found that the aggregated droplet will rotate when two droplets aggregate under small droplet diameter ratio, which is caused by the asymmetry aggregation process. The oscillation process intensifies when three droplets impact and aggregate on the wall, as a result, the aggregated droplet is easier to adhere to the wall. The viscous dissipation in the aggregation of droplets is huge, and the total viscous dissipation energy accounts for about 50% of the total energy when the aggregated droplets rebound. The influence of droplet diameter on the V⁎ (rebound recovery coefficient) of the aggregated droplet and the rebound/adhesion results are dominated by the viscosity effect. While the influence of the parameters involving the initial spatial arrangement of droplets is dominated by the oscillation process, which will reduce the effective rebound kinetic energy, making a lower V⁎ and the aggregated droplet easier to adhere.

Improved Combustion Performance of Fluororubber-Coated Micro-Nano Composite Aluminum Powder

In order to improve the reaction rate and reaction degree of aluminized explosives, the micro-nano composite aluminum powder was fabricated by a new method of in situ electro-explosion. The combustion performances of the composite aluminum powder were studied. The results showed that the micro-nano composite aluminum powder was like a “sea urchin structure” with many nano-sized powders around a single micro-sized aluminum particle. The heat of combustion was 25.67 MJ/kg at 3 MPa oxygen pressure, and the rising rate of pressure was particularly obvious. The ignition performance in an air environment was much better than the micro-sized aluminum powder. At the same time, the reaction process of the micro-nano composite aluminum powder was analyzed. The reaction can be divided into three stages, the decomposition of fluororubber between 500 and 600 °C, then melting, and the first step of the oxidation of aluminum powder occurred between 600 and 700 °C. In the third stage, the micro-nano composite aluminum powder reacted violently around 1000 °C and the released energy reached 3779 J/g. The micro-nano composite aluminum powder had excellent combustion performance and a good application prospect in high-power energy storage materials.

Experimental study on sound absorption performance of microporous aluminum square tube space absorber

The aluminum square tube is one of the ceiling materials that have been produced in recent years. It has become the most popular product in the decoration market because its lines are bright and clean with distinct layers, reflecting the simple modern style, and it is easy to install and dismantle. However, the aluminum square tube used in the market is mostly a single aluminum panel structure, mainly used for decoration, without sound absorption and noise reduction. In order to improve the sound absorption properties of the aluminum square tube, a microporous aluminum square tube space absorber is proposed. The reverberation chamber method is used to investigate the sound absorption properties of the microporous aluminum square tube. The results show that the sound absorption performance of the aluminum square tube can be greatly improved by the formation of micropores on it. The sound absorption performance of the aluminum square tube perforated on three sides is better than that of the aluminum square tube perforated on only two sides. In the case of perforation on only two sides, with the increase in the height of the perforated surface, the peak value of sound absorption is gradually increased. In addition, the sound absorption peak gradually shifts to the low-frequency direction as the distance between the perforated surfaces increases. The reasonable design of structural parameters of microporous aluminum square tube can make it have beautiful decorative effect and good sound absorbing effect.

Experimental and numerical investigation of thermal-hydraulic performance of bi-metallic (Al-Cu) plate fin heat sink

In this research, an experimental study of thermal-hydraulic performance of bi-metallic (Al-Cu) plate fin heat sink (PFHS) under forced convection in wind tunnel is investigated. The key parameters such as pressure drop, Reynolds and Nusselt numbers, heat transfer coefficient, thermal resistance, power pumping and profit factor have studied. Then the PFHS has simulated and the results have validated with test. A good agreement is seen in the results of pressure drop between test and simulation. The results show an increase of performance of the applied bi-metal sink compared with similar single aluminum one in available literature. Finally, in order to improve the thermal behavior of PFHS, porous materials have been used in numerical simulation. Because of using a porous layer in the fin spaces, the pressure drop has been increased in comparison with the normal state. Thus, pumping power has increased which means the more energy consumption is needed for the cooling process so the profit factor is decreased. On the other hand, the amount of thermal resistance is decreased by 12% compared with bi-metallic PFHS without porous materials. The results of this study could be used as the fundamental of the future researches.

Characterization of flexible aluminosilicate bulk fibers and fibrous mats fabricated by facile electrospinning

This paper reports a facile electrospinning method to synthesize aluminosilicate fibers by using aluminum chloride hexahydrate as single aluminum precursor, which contains no harmful or hazardous chemicals in the precursor sol. The results of Fourier transform infrared, X-ray diffraction, simultaneous thermogravimetry and differential scanning calorimetry show that the sols are diphasic. The thermal decomposition behavior, crystallization process and microstructure of the fibers are discussed in detail. The main components of aluminosilicate fibers heat-treated at 1200 °C are mullite (Al6Si2O13), alumina (α-Al2O3) and amorphous silica, while the alumina phase disappears when the molar ratio of Si to Al is below 1.5. The diameter and microstructure of fibers with different Si/Al molar ratios are obviously different, which is related to the large difference in conductivity of spinning sols. Bulk fibers and fibrous mats with good flexibility can be easily obtained by using alternative collectors. The tensile strength of the fibrous mats can reach 2.63 MPa and 1.52 MPa after heat-treated at 1000 °C and 1200 °C, respectively. The aluminosilicate fibers fabricated in this work has a noticeable potential in high temperature fields and related applications.

Analyzing the influence of the investment casting process parameters on microstructure and mechanical properties of open-pore Al–7Si foams

Aluminum alloy foams with high specific compressive strength and good energy absorption capacity are widely used as structural materials and shock absorbers. The investment casting process offers an interesting opportunity for the production of open-pore aluminum foams. However, foam casting differs from casting of solid parts, and there is a lack of practical knowledge about the microstructure tuning of the ultra-thin cast struts. Our study focuses on the influences of the casting conditions such as mold temperature on the microstructure and consequently on the mechanical properties of aluminum-silicon alloy foams. We investigated microstructural features using various metallography techniques and defined mechanical properties under uniaxial compression test. Here, we observed improvements in the strut microstructure together with decrease of the mold filling by reduction of the mold temperature. Microstructure improvements involve transformation of a single dendritic aluminum grain in each strut to globular grains along with a more homogeneous distribution of the silicon particles across the strut cross-section. These changes bring higher ductility and energy absorption efficiency to the foams, which are evident from the smoother plateau of the stress-strain curves. Decline of the mold filling, on the other hand, has negative effect on the overall mechanical properties.

The mechanical and microstructural response of single crystal aluminium to one dimensional shock loading: The effects of orientation

A series of plate impact experiments have been performed on the three principal orientations of single crystal aluminium: [100], [110] and [111]. Experiments were designed to probe the Hugoniot Elastic Limit, spall strength and Equation of state as well as understand the microstructural response, via transmission electron microscopy, Transmission Kikuchi Diffraction and mechanical testing of shocked material. Results from this work, show that orientation affects the HEL and spall strength in a similar manner to the quasi-static uniaxial stress compressive response, with [100] and [110] being similar and [111] significantly stronger. This correlates with expectations from considerations using the Schmid analysis. However we have noted that similar studies in copper yield a different ordering of the HELs. We have reconciled those differences using an analysis based on second order elastic constants. However the shocked microstructures and post shock quasi-static mechanical response are strongly influenced by orientation. The [100] orientation shows a response typical of high stacking fault face centred cubic metals, consisting of equiaxed subgrains and a strong post shock hardening during quasi-static mechanical testing, similar to results in polycrystalline aluminium. In contrast, the [110] and [111] orientations have a microstructural response more similar to polycrystalline aluminium after repeated shock loading excursions, combined with much lower post shock hardening during mechanical testing. This suggests that these orientations require much greater dislocation activity to achieve the same plastic deformation as [100]. This would appear to agree with the much higher degree of work hardening observed in these orientations compared to [100].

Homoepitaxial growth of 3-inch single crystalline AlN boules by the physical vapor transport process

Single crystalline aluminum nitride (sc-AlN or AlN) boules with a diameter of 3-inch (Φ76 mm) were successfully prepared by the physical vapor transport (PVT) process. The initial homoepitaxial growth run was performed on an aluminum nitride seed sliced from a Φ51 mm aluminum nitride boule, and diameter enlargement was conducted iteratively via the lateral expansion technique until a Φ76 mm boule was achieved. During the diameter expansion growth runs, the crystal shape transitioned from a hexagonal pyramid to a cylindrical pyramid. After the standard slicing and wafering processes, the as-obtained substrates were characterized by high-resolution X-ray diffraction (HRXRD), preferential chemical etching, and optical spectroscopy. The characterization results revealed that the aluminum nitride substrates showed good crystallinity and excellent UV transparency, although a slight quality deterioration was observed when the crystal size was expanded from Φ51 to Φ76 mm, while the deep-UV (DUV) transparency remained very similar to that of the aluminum nitride seeds. The Φ76 mm aluminum nitride boules obtained in this study are an important milestone towards achieving Φ100 mm (4-inch) aluminum nitride, which are essential for the rapid commercialization of deep-UV optoelectronics and ultra-wide bandgap (UWBG) electronics.

硼添加对铝胁迫栝楼生长和生理的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 硼添加对铝胁迫栝楼生长和生理的影响 DOI: 10.5846/stxb202202220419 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金（32001224，41702181）；2021年国家级大学生创新创业训练计划（202110345017） Effects of exogenous boron on growth and physiology of Trichosanthes kirilowii Maxim. under aluminum stress Author: Affiliation: Fund Project: The National Natural Science Foundation of China (General Program, Key Program, Major Research Plan)，the 2021 National Undergraduate Training Program for Innovation and Entrepreneurship 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为揭示硼对缓解栝楼（Trichosanthes kirilowii Maxim.）铝（Aluminum）毒害的生理机制，以耐铝性强的安国栝楼和耐铝性弱的浦江栝楼为材料，研究了50 μmol/L硼酸（H3BO3）对300 μmol/L Al3+胁迫下栝楼幼苗生长、铝积累、抗氧化能力和细胞壁组分的影响。结果表明：铝胁迫下，植株的根长、株高、鲜重和干重降低，超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）活性受到显著抑制，安国栝楼、浦江栝楼根尖丙二醛（MDA）含量分别增加256.1%、278.2%，细胞壁多糖含量、果胶甲酯酶（PME）活性、根尖铝积累量显著提高，果胶甲基酯化度（DM）和3-脱氧-D-甘露-辛酮糖酸（KDO）含量降低。外源硼可以缓解铝胁迫对栝楼幼苗生长的抑制作用，安国与浦江栝楼的抗氧化酶活性显著提升，MDA含量、细胞壁多糖含量、PME酶活性均降低，安国栝楼果胶DM值恢复至正常水平的91.5%，浦江栝楼KDO含量较单铝处理组上升52.0%，活性铝结合位点减少，有效降低了根尖铝含量并维持其形态结构。因此，硼信号能通过调节细胞壁多糖组分且稳定其网格结构，减少根尖对铝的吸收，同时增强抗氧化酶活性，缓解铝胁迫导致栝楼幼苗生长中的次生氧化胁迫，提高栝楼幼苗对铝毒环境的耐受性，且对耐铝性强的安国栝楼作用效果较好。研究结果可为改良酸铝胁迫下作物的生长环境提供理论指导。 Abstract:Aluminum toxicity, a major abiotic stress that inhibits plant growth and development, has become one of the main factors reducing agricultural yield. To reveal the physiological mechanism of boron on alleviating aluminum toxicity of Trichosanthes kirilowii Maxim., seedlings from Anguo (with strong Al-tolerance) and Pujiang (with weak Al-tolerance) varieties of T. kirilowii were selected for water culture experiments and the effects of boron treatment (50 μmol/L) on varieties' growth, aluminum accumulation, antioxidant capacity, and cell wall components under aluminum stress (300 μmol/L) were studied. The results showed that 300 μmol/L Al3+ stress inhibited the root length, plant height, fresh weight, and dry weight of the plant. The activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were significantly decreased, and the content of malondialdehyde (MDA) in root tip of T. kirilowii in Anguo and Pujiang varieties increased by 256.1% and 278.2%, respectively. Aluminum stress also significantly enhanced the content of cell wall polysaccharide, pectin methylesterase (PME) activity, and root tip aluminum accumulation. However, the degree of pectin methyl-esterification (DM) and the content of 3-deoxy-d-mannose-octanoic acid (KDO) were strongly inhibited. Exogenous boron could alleviate the inhibitory effect of aluminum stress on the growth of T. kirilowii seedlings. The antioxidant enzyme activities of T. kirilowii in Anguo and Pujiang varieties were increased significantly. The MDA content, cell wall polysaccharide content, and PME enzyme activity were decreased. In addition, the pectin DM value of Trichosanthes in Anguo variety returned to 91.5% of the normal level, and the KDO content of T. kirilowii in Pujiang variety increased by 52.0% compared with that in the single aluminum treatment group. As a result, the active aluminum binding sites decreased, effectively reducing the aluminum content in the root tip and maintaining its morphological structure. Therefore, boron improved the tolerance of T. kirilowii seedlings to aluminum toxic environment by regulating the polysaccharide components of cell wall and stabilizing its grid structure to reduce the absorption of aluminum by root tips, and enhancing the activity of antioxidant enzymes to alleviate the secondary oxidative stress in the growth of T. kirilowii seedlings, which has a better effect on Anguo variety with stronger tolerance to aluminum toxicity. The research in this paper can provide theoretical guidance for improving the environment for crop growth under acid-aluminum stress. 参考文献 相似文献 引证文献

Single Vs Multichannel Silica-Pectin Ultrafiltration Membranes for Treatment of Natural Peat Water

A comparative study was undertaken to investigate the potential of silica-pectin ultrafiltration membrane on varied operation pressure (0.1-0.3 MPa). Cross-flow ultrafiltration works were explored with tubular alumina substrates in single and multichannel configuration. The silica-pectin sol was prepared from TEOS as silica precursor by sol-gel method, afterward pectin was templated into the silica sol to induce carbon on it. Thereafter, both of single and multichannel alumina substrates was coated by the silica-pectin sol via inner coating technique. The study exhibited better performance of multichannel silica-pectin ultrafiltration membrane (with 4 bores) compared to the single channel membrane in terms of the permeate quality of UV254 rejection, as well as the permeate flux. The UV254 rejection of multichannel silica-pectin ultrafiltration membranes conducted over 84% in compliance with highest permeate fluxes of 234.3 L.m-2.h-1.bar-1 at high operation pressure (TMP 0.3 MPa). The multichannel ultrafiltration membrane permeate flux in this work is slightly high 60-75% over single channel. Hence, both single and multichannel silica-pectin membranes exhibited steady neutralized permeate fluxes under TMP 0.3 MPa conditions for natural 100% peat water concentration, which indicates that fouling is not occurred during filtration time up to 60 min. Therefore, multichannel silica-pectin ultrafiltration membrane in this work is success to treatment of natural peat water, that the natural organic matter removal was found to be fit for uses as clean water sources.

Effect of porosity on shock propagation behaviour of single crystal aluminium: A molecular dynamics investigation

Materials' response to shock waves is largely affected not only by their inherent atomic structure but also by their physical structure. Current study involves analysis of shock propagation behaviour of single crystal aluminium (Al) specimens with different levels of porosities at nanoscale under a compressive shock loading using three dimensional molecular dynamics (MD) simulations. Solid, two dimensional array of pores, and three dimensional array of pores in the single crystal Al specimen were considered for detailed analysis of the shock response. It is observed that the porosity causes time delay in the travel of shock wave from front end of the surface to the rear end. The computational results indicate that the porosity results into increase in time of shock wave travel and it is found that the maximum porosity (47% in this simulation) causes 4 times the time of travel taken in solid Al specimen. The shock wave causes various sequential phenomenon in the Al specimen from compression to rarefaction which further leads to spalling of the material. The study also reveals that the pore walls act as a reflecting wall to the shock wave which causes secondary rarefactions and spalling phenomenon. Analyses show that the deformation in the material during shock loading is largely dominated by Shockley partial dislocations.

Research Progress in the Preparation of Aluminum Foam Composite Structures

Closed-cell aluminum foam has a porous structure and metal properties due to its unique composition. As a structural material, it has the advantages of being lightweight, having a large specific surface area, and having high specific strength and stiffness. As a functional material, it can be used for sound and noise reduction, heat insulation, electromagnetic shielding, damping, and energy absorption, but it also has poor mechanical properties and poor surface flatness, and can be easily corroded. Considering the abovementioned problems, researchers have gradually extended their research on foam materials. Under the research of many international scholars, studies have shifted from simple aluminum foam preparation to improving and optimizing aluminum foam composite structures (AFCSs). From the perspective of development prospects, AFCSs have better application prospects than single aluminum foam. In this paper, the research progress on the preparation technology of AFCSs in recent years was reviewed based on the performance enhancement mechanism of aluminum matrix composites and the structural characteristics of aluminum foam. The morphology and pore structures of closed-cell AFCSs under different preparation methods were summarized. However, due to the limitations of existing experimental conditions, this paper only considered the advantages and disadvantages of AFCS preparation methods. The improvement of AFCS preparation technology, the development of the potential properties of AFCSs, and the promotion of AFCS industrial applications were also considered.

Springback Behavior of Aluminum/Polypropylene/Aluminum Sandwich Laminates

The springback of sheet metals after forming has been widely studied for decades using numerical and experimental methods. Many of these springback studies involve aluminum alloys. This study aims to understand the springback behavior of aluminum-polypropylene-aluminum laminates as they are being used increasingly in automotive and other applications because of their weight saving potential. A finite element model of the draw bending of a U-channel based on Numisheet’93 benchmark study is built using LS-DYNA. First, the model is validated and studied for springback prediction of single AA5182-O aluminum alloy sheets, and then it is extended to the study of the springback behaviors of AA5182-O/polypropylene/AA5182-O laminates with various combinations of core and skin thicknesses. The numerical model is also validated by experiment. Effects of various tool design and process parameters, such die radius, punch radius and blank holder force, on the springback of the sandwich laminates are studied. The effect of numerical modeling parameters is also considered.

Influence of Friction Stir Processing on the Mechanical and Microstructure Characterization of Single and Double V-Groove Tungsten Inert Gas Welded Dissimilar Aluminum Joints

Influence of Friction Stir Processing on the Mechanical and Microstructure Characterization of Single and Double V-Groove Tungsten Inert Gas Welded Dissimilar Aluminum Joints