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We investigated the relationship between porosity and flexoelectricity for aluminum (Al)/polyvinylidene fluoride (PVDF) composites. Neat PVDF, composites of micron aluminum (μAl)/PVDF, and composites of nano aluminum (nAl)/PVDF were 3D printed, and the flexoelectric response was measured using a cantilever beam test setup. Voids (up to 72.4 mm3) were incorporated into the samples by decreasing the infill percent of the 3D printed material. We found that increasing the porosity via millimeter scale voids incorporated into the infill pattern decreased the average effective flexoelectric coefficient relative to the near full-density (100% infill) control samples. This contrasts with other studies that have shown increasing micron scale porosity increases the flexoelectric coefficient. In addition, we measured higher flexoelectric responses for nAl/PVDF than μAl/PVDF as well as for samples printed by the Hyrel 3D SR printer as opposed to the Ender 3 V2 printer. These results indicate that charge generation due to flexoelectricity can be altered by changing parameters such as porosity, particle size of inclusions, or manufacturing method. Smaller voids and fine particles can induce larger strain gradients than larger inhomogeneities, leading to increased flexoelectric coefficients. A competing effect is that more porosity leads to less materials, which can decrease the flexoelectric coefficient. [ABSTRACT FROM AUTHOR]

High-pressure effects can be used to effectively optimize the thermoelectric performance of wide-bandgap oxides. We build upon this finding to show that the synergistic effects of doping with aluminum and graphene composite give excellent thermoelectric performance under high pressure. By employing the parabolic band model, the Pisarenko curves are derived at different pressures, coupled with the band structure of Al-doped ZnO. An analysis indicates that pressure-induced narrowing of the bandgap in Al-doped ZnO reduces the electron excitation energy, thereby optimizing the electrical properties of the samples. The Debye Callaway model is also used to fit the lattice thermal conductivity of the samples, thus enabling an in-depth analysis of the phonon scattering mechanisms. Our analysis suggests that graphene composites significantly enhance point defect scattering and Umklapp scattering, thus increasing the phonon relaxation time and effectively reducing the lattice thermal conductivity of the samples. The improvement in the figure of merit (zT) of ZnO is attributed to the simultaneous enhancement of its electrical properties under high pressure and the synergistic optimization of reducing the lattice thermal conductivity through doping and composites. In this work, we consider a fixed doping ratio of Al and a constant proportion of graphene composite, and analyze the microstructure and thermoelectric properties of 0.1C–ZnAl 0.04 O (C–ZnAlO) samples synthesized under pressures ranging from 1 to 5 GPa, with the aim of elucidating the influence of pressure and graphene composite on the electro-acoustic transport properties of ZnO. We find that the zT value for a sample synthesized at 5 GPa is increased to 0.27 at 973 K. [ABSTRACT FROM AUTHOR]

The hybrid sandwich structures possessing composite faces and an aluminum foam (ALF) core exhibit lightweight and superior impact resistance. However, limited studies pay attention to the mechanical behavior of hybrid sandwich beams with various ALF densities. The present article has focused on the influence of foam densities on the quasi‐static and low‐velocity impact (LVI) behaviors of hybrid sandwich beams with aramid‐fiber‐reinforced polymer (AFRP) faces and ALF core. The failure mode, loading response, and energy absorption of sandwich beams have been obtained experimentally and the failure map with a wide range of dimensional configurations has been established theoretically. Increasing core density significantly enhances the load‐carrying capacity of the sandwich beam, and the enhanced effect becomes more obvious for a thicker core. The medium‐density ALFs provide the maximum specific energy absorption, while the high‐density ALFs offer the highest energy absorption for hybrid sandwich beams. The applicability of core densities in hybrid sandwich structures is provided. Highlights: Normal strain distribution under quasi‐static loading is analyzed using DIC.AFRP face microbuckling provides higher impact resistance than core failure.The applicability of core density in hybrid sandwich structures is given. [ABSTRACT FROM AUTHOR]

The high-energy ball milling process was applied to fabricate a composite material from 7075 aluminium alloy milling chips, silicon carbide, and titanium dioxide powders. Raw materials were ground, and the obtained powders were cold pressed and sintered. It was demonstrated that this method can be used in the recycling of aluminium alloy scrap characterised by a high surface-to-volume ratio, and also that chemical removal of the oxide layer from chips is not necessary. The finest particles, with 50 vol.% of their population below 36 μm, were obtained after grinding for 60 min at a 1000 rpm rotational speed. Such an intensive grinding was necessary to fabricate the compact composite material with a homogeneous microstructure and a low porosity of 0.7%. The corrosion resistance of the composites was studied in 3.5 wt.% NaCl solution using cyclic voltammetry and electrochemical impedance spectroscopy, and corrosion rates in the range of ca. 342 and 3 μA∙cm−2 were obtained. The corrosion mechanism includes aluminium alloy dissolution at the matrix/reinforcement interphase and around intermetallic particles localised within the matrix grains. [ABSTRACT FROM AUTHOR]

SiCp/Al-Fe-V-Si composites exhibit complex deformation behaviors at both room and high temperatures because of the presence of SiC reinforcement particles and numerous fine dispersed Al12(Fe, V)3Si heat-resistant phases. In this work, an artificial neural network (ANN) constitutive model was established to study the deformation behavior of SiCp/Al-7.75Fe-1.04V-1.95Si composites over a wide temperature range based on uniaxial compression. Then, microstructural observation, finite element analysis, and processing maps were utilized to investigate the plastic workability. The results showed that the ANN model fit the experimental stress–strain curves with high accuracy, achieving an R2 value of 0.999. The ANN model was embedded into finite element software to study plastic deformation behaviors, which indicated that this model could accurately compute the plastic and mechanical response during the compressing process. Finally, a thermomechanical processing diagram was developed, revealing that the optimal processing parameters of the SiCp/Al-7.75Fe-1.04V-1.95Si composites were a deformation temperature of 450–500 °C and a deformation rate of 0.1–0.2 s−1. [ABSTRACT FROM AUTHOR]

This study focuses on analyzing the damages and ballistic limit for the fiber metal laminate (FML) and nano-silica reinforced FML. FML materials are hybrid sandwich composite materials used in lightweight structural applications. FML is constructed as a sandwich structure by bonding an aluminum alloy and a glass fiber reinforced composite. To enhance the impact strength of the FML composite, it was reinforced with nano-silica particles within the epoxy resin at various concentrations ranging from 1 wt% to 7 wt%. The laminates are then subjected to high-velocity impact tests using a single-stage gas gun setup, to assess the failure modes of the FML in an aluminum sheet and nanocomposite layers. The influence of nano-silica on natural frequency and damping factor is also examined by using a shock sensor and DAQ (Data Acquisition system). Results indicate that the FML laminate containing 5 wt% nano-silica demonstrates superior impact resistance compared to other filler percentages, as demonstrated by the ballistic limit and damage assessment. The ballistic limit for the pure FML laminate without nano-silica is 98 m/s, whereas the FML laminate containing 5 wt% nano-silica exhibits a peak value of 112 m/s, presenting a notable 14.3% increase in ballistic limit compared to the pure FML. Additionally, the dynamic response analysis reveals changes in the natural frequency values of the laminates before and after impact, indicating permanent damage to the laminate structure. [ABSTRACT FROM AUTHOR]

This research paper investigates the frictional and thermomechanical properties of a copper (Cu) free non-asbestos organic (NAO) composite for developing brake friction material for automotive/railway applications. Reduced-scale brake composites were manufactured and tested in a pin on disc tribometer. The effect of aluminum (Al) chips on the dry sliding wear behavior of acrylonitrile-butadiene rubber (NBR) modified phenolic resin-based reduced-scale friction composites was investigated. Other common ingredients of friction materials like fiber, filler, and friction modifiers were not included to get the specific effect of Al on the various properties of the composites. Four composites were prepared with varying Al content, for example, 25, 50, 75, and 100 phr (parts per hundred resins). The average COF increases by ∼70% for 75 phr Al loaded composite (optimum composition) compared to the base composite (devoid of Al). However, mechanical properties, such as hardness and flexure strength, decrease with increasing phr of Al, although compressive strength does not change significantly. The optimum composite exhibits the lowest specific wear rate among Al chips loaded composites. The optimum composite also shows nearly three times improvement in thermal conductivity compared to the base composite. The wear behavior of the composites has been analyzed from the scanning electron microscopy (SEM) images. [ABSTRACT FROM AUTHOR]

Silicon carbide particle-reinforced aluminum matrix composites (SiCp/Al) have been widely used in many areas due to their good physical and mechanical properties. However, because the material contains SiC particles with high hardness, processing is difficult and the processing quality of milling is poor. Ultrasonic vibration-assisted longitudinal torsion milling (LTUVAM) has great advantages in cutting difficult materials because it can effectively reduce the cutting force and cutting heat and improve the surface quality of the workpiece. Therefore, the kinematic analysis of LTUVAM is carried out, the material removal mechanism of 60% SiCp/Al is studied by the method of simulation and experiment, and the effects of machining parameters on the cutting force, cutting heat, and surface quality of the material were analyzed and using the traditional milling (CM) compared. The simulation and experimental results show that LTUVAM can improve the particle crushing rate, effectively reduce the cutting force and cutting heat under the relevant parameters, and improve the surface quality. [ABSTRACT FROM AUTHOR]

This study aims to modernize commonly preferred hybrid aluminum composites in the automotive and defense industries. For this purpose, Al-4Cu/B4C-SiC hybrid composites were manufactured using the hot pressing method and their microstructure, mechanical, and tribological properties were investigated. SEM/EDS analyses of the samples were conducted to examine morphological characteristics. Hardness, relative density, and three-point bending tests were performed on the produced samples. Additionally, wear tests were conducted under dry sliding conditions and different loads (5-10-15 N) to investigate tribological properties. The addition of hybrid reinforcements resulted in high hardness (88.54 HB) and relative density (98.83%) values. The highest bending stress (556.9 MPa) was observed in sample AC-4 (Al-4Cu/2B4C-2SiC). The lowest mass loss (1.1 × 10−3 g) was encountered in sample AC-6 (Al-4Cu/6B4C-6SiC), where all reinforcements were present together. Plastic deformation, oxidation, and residual wear mechanisms were identified on the worn surfaces of the samples. Consequently, the addition of hybrid reinforcements to Al-4Cu composites shows promising potential in enhancing the mechanical and tribological performance of the composites. [ABSTRACT FROM AUTHOR]

The major purpose of this study is to analyze the resistance of honeycomb ceramic matrix composites to penetration and to explore the effect of the performance characteristics of the filler materials on this capability. We used alumina ceramics, polyurea, quartz sand powder, and boron carbide powder to manufacture composite materials, and conducted impact tests and numerical simulations on them. The simulation results of Abaqus were found to be very consistent with the test results. The results demonstrate that the polyurea coating and filler materials may effectively improve the anti-penetration penetration performance of the composites, and different filler materials have varying energy absorption effects. Extended research on composites was carried out utilizing experimentally validated numerical models with filler materials comprising silicon carbide, aluminum nitride, and silicon nitride. After a comparative analysis of the simulation results of different composites, compared to quartz sand composites, the energy absorption efficiency of boron carbide composites increased by 12.03 %, silicon carbide composites increased by 14.63 %, aluminum nitride composites increased by 15.16 %, and silicon nitride composites increased by 18.29 %. Among the relevant materials in this study, there exists an optimal value of the stress wave impedance difference between the matrix material and the filler material. Honeycomb ceramic matrix composites with an ideal combination of stress wave impedance differences can considerably increase the anti-penetration efficiency of the composites. [ABSTRACT FROM AUTHOR]

This article presents an experimental investigation of the WEDM (Wire Electrical Discharge Machining) performance of Al-TiB2 composites fabricated using ultrasonic vibration-assisted stir casting and containing four different weight percentages (1%, 2.5%, 4%, and 5.5%) of TiB2 particles. Key machining parameters, namely pulse-on time, wire feed rate, and pulse-off time, are varied at three levels suitable for machining aluminium base material while minimizing wire breakage. Cutting speed, material removal rate, and kerf width are observed individually for each selected level of these process parameters. Surface features are assessed using SEM (Scanning Electron Microscope), EDAX (Energy Dispersive X-ray Spectroscopy), 3D optical surface profilometer, and optical microscopy. Notably, the roughness values are lower in the 4% and 5.5% TiB2 composites compared to the base matrix. This reduction in roughness is due to the protective role of the particles, which shield the surface from melting during the WEDM process. Melting and re-welding phenomena were observed throughout the machining process. It is observed that higher pulse-on time generates harsh sparks, leading to rougher surfaces that include melted zones and pits. The WEDM operations performed on the 5.5 wt% reinforced composite surface result in a significant reduction in roughness, decreasing from around 5 µm to approximately 2.7 µm. [ABSTRACT FROM AUTHOR]

Featured Application: A paper-based triboelectric nanogenerator using carbon nanotube composite papers, as developed in this study, has the potential to be used as an energy harvester in fields such as the Internet of Things (IoT). A unique triboelectric nanogenerator (TENG) using carbon nanotube (CNT) composite papers is proposed in this work. CNT composite papers can be fabricated easily using a method based on the production of Japanese washi paper. To obtain and evaluate the proposed TENGs, several types of CNT composite papers and aluminum plates were prepared. As the CNT composite paper contained many paper fibers, it was expected to be negatively charged, and the aluminum plate was expected to be positively charged across the triboelectric series. Through various experiments, it was confirmed that CNT composite papers could be used as TENGs. In addition, it was found that when a CNT composite paper was used, it contributed to triboelectricity generation, and the contained CNTs efficiently transferred the generated charge to the electrodes. Furthermore, output voltages approaching a maximum RMS value of 300 mV could be obtained. The results of this study will aid in the practical application of paper-based TENGs in the near future. [ABSTRACT FROM AUTHOR]

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The combination of fluoropolymer and nano‐thermite has been a research focus in the field of materials in the field of energy and storage in recent years, but it faces the problem of uneven mixing of fluoropolymer and nano‐aluminum powder (nAl). Therefore, it is of great significance to obtain a fluorine/aluminum uniform composite by a solid/solid phase mixing method. In this paper, Pickering emulsions effectively blend difficult‐to‐mix powders of nAl and solid bulk fluoroelastomers on the micro‐ and nanoscale. The emulsion was prepared by Pickering emulsion with an ethyl acetate solution of fluororubber as the oil phase and perfluorocarboxylic acid‐modified nano‐aluminum powder as a surfactant. The effects of oil/water ratio, fluororubber/aluminum ratio, and standing time on the stability of the emulsion were studied. The nano‐aluminum powder/fluororubber composite microspheres were prepared and their morphology, thermal decomposition, and combustion properties were characterized. The results showed that the emulsion prepared with the oil/water ratio of 1:8 and m(fluororubber):m(modified nano‐aluminum powder) of 5:1 had good stability and dispersion. The transmission electron microscopy (TEM) and scanning electron microscopy (SEM) results showed that the complex was observed to be regular spherical and the size was about 10 µm, and the composite microspheres prepared by the Pickering emulsion had good. The TG‐DSC results showed that the decomposition of the composite microspheres started at about 450 °C and finished at 519 °C. The composite microspheres prepared in this paper are stable and rapid in exotherm, with a combustion rate of 33 cm s−1 and excellent combustion performance. The Pickering emulsion introduces a new idea for the preparation of thermite by mixing the solid reactants at the micro‐nano level without introducing substances that reduce the energy of the system. [ABSTRACT FROM AUTHOR]

Al–Ti–C/7075 aluminum matrix composites (referred to as 7075-ATC) containing uniformly distributed TiC particles and traces of TiAl3 particles were produced by introducing 2 wt. % Al–Ti–C master alloy through stir casting. Isothermal thermal compression behavior at 300 °C–450 °C and 0.001 s−1 to 1 s−1 strain rates was studied in a Gleeble-3800 thermal simulation tester. Peak stress is influenced by deformation temperature and strain rate, reaching its maximum at low temperatures and high strain rates. The activation energy of the final thermal deformation is 150.11 kJ/mol, attributed to particle reinforcement. A sinusoidal hyperbolic Eigen structure equation for composites considering strain compensation is developed to describe the rheological stresses in composites. Dynamic recrystallization at 450 °C and a strain rate of 0.001 s⁻1 enhances composite molding properties. After hot compression, composites exhibit higher activation energy (Q) than cast 7075 and in situ particle-reinforced 7075 due to the obstruction of dislocations by the particles, grain refinement, and pinning effect on the grains. Based on the experimental results, an intrinsic model considering strain compensation was developed to accurately predict the thermal deformation behavior. EBSD results indicated that dynamic softening primarily occurred through dynamic restitution and partial recrystallization. The efficiency of softening peaked at 39% under a strain of 0.6, deformation temperatures between 350 °C and 450 °C, and strain rates ranging from 0.0009 s⁻1 to 0.0111 s⁻1. [ABSTRACT FROM AUTHOR]

Friction stir welding of cast and rolled-state aluminum matrix composites is extensively used in many industries, and the speed at which the mixture is stirred profoundly influences the structure and characteristics of the welded connections. The present study investigates the microstructure and mechanical properties of the as-cast and as-rolled (ZrB2 + Al3Zr) particle-reinforced aluminum matrix composites. The welded joints were subjected to friction stir welding at a welding speed of 60 mm/min and stirring speeds of 1000, 1200, and 1400 rpm, separately. At a rotational speed of 1200 rpm, the welded joints exhibit optimal performance with an average hardness of 71.07 HV, a tensile strength of 183.9 Mpa, and an elongation of 16.7%. The weld core region generates precisely shaped equiaxed grains, while the weld matrix facilitates a significant amount of dislocation entanglement. At a rotational speed of 1200 rpm, the grain refinement effect is fully optimized, resulting in an average grain size of 2.94 μm. The recrystallized organization accounts for 70.6% of the grain size. Both types of reinforcing particles are adequately crushed, with the smallest particle size of ZrB2 particles being less than 100 nm and the smallest particle size of Al3Zr particles being less than 1 μm. The two methods of weld reinforcement are fine crystal strengthening and Orowan strengthening. [ABSTRACT FROM AUTHOR]

Developing of lightweight materials with extremely low thermal expansion is crucial across various sectors. While Invar exhibits a coefficient of thermal expansion (CTE) below 3 × 10−6 °C−1, its heavy nature limits its applicability in electric vehicles and aerospace fields. The present study introduces Al6061/SiC composites produced by the nitrogen-induced self-forming aluminum composite (NISFAC) process, wherein CTE is successfully tailored down to an unprecedented value of 2.12 × 10−6 °C−1 at 100 °C by changing the volume fraction of SiC from 0 to 65%. In-situ AlN, formed at the interface between Al6061 and SiC particles during the NISFAC process, plays a crucial role in minimizing the thermal expansion of the composites by improving crystallographic match and adhesion between SiC particles and the Al matrix. [ABSTRACT FROM AUTHOR]

Highlights To address the challenges of achieving strong adhesion between aluminum face sheets and composite cores (3D carbon felts) in sandwich structures, this work presents a novel approach that prioritizes safety, environmental sustainability, and ease of processing. The 3D CFs/Epoxy core was modified with Triton X‐100 in amounts from 0 to 10 wt% of the epoxy resin. The aluminum alloy face sheets were anodized at voltages from 0 to 11 V, using a NaCl‐based anodizing process. The technique of anodizing can enhance the bond between the aluminum face sheets and the 3D CFs/epoxy core, resulting in improved mechanical performance of the composite, including flexural and compressive testing, as well as dynamic mechanical analysis. The composite, embedding 3D CFs foam in epoxy resin, has a storage modulus 65.1% higher than pure epoxy at 2070 MPa. In addition, increasing Triton X‐100 content (1–10 wt%) decreases the storage modulus from 1886 to 1314 MPa and the glass transition temperature from 68.3 to 62.8 °C. Additionally, with Triton X‐100 concentrations of 1 to 10 wt%, the flexural modulus of the epoxy reinforced by 3D CFs drops from 3951.8 to 2400 MPa, and the flexural strength decreases by 55.3% from 174 to 112 MPa, indicating reduced structural rigidity. For sandwich composites with anodized aluminum face sheets, a 7 V anodizing voltage boosts the flexural modulus from 17.8 GPa (0 V) to 36.2 GPa. At 7 V, compressive strength and strain rise by 346.9% and 995.5%, respectively. Flexural toughness peaks at 11239 KJ/m3 with 5 wt% Triton X‐100. Developed new sandwich epoxy composites consisting of anodized aluminum sheet treated with NaCl and modified 3D carbon felts epoxy composites using Triton X‐100. Aluminum face sheets underwent an anodization at different voltages (0, 5, 7, 9, and 11 volts), aiming to enhance the bonding between the aluminum sheets and the 3D CFs/epoxy core. Triton X‐100 was utilized to modify the epoxy matrix at various concentrations (0 to 10 wt%) for improving the flexibility of the sandwich core. The sandwich composites incorporating the un‐anodized face sheet have shown flexural modulus of about 17.8 GPa. The modulus achieves its maximum value of 36.2 GPa when anodized at 7 V, indicating a 103% increase. The flexural strength of sandwich composites increases by 13% (272 MPa) when the Triton X‐100 concentration is raised to 5 wt%, compared to the 240 MPa flexural strength of the Al face sheet anodized at 7 V. [ABSTRACT FROM AUTHOR]

Aluminium metal matrix composites are widely used in automotive, aerospace, marine, and structural engineering due to their high strength-to-weight ratio and superior mechanical properties. Optimizing friction stir process parameters is critical to enhancing the performance of these materials. This study investigates the effects of FSP parameters such as rotational speed, tilt angle, and traverse speed, on the mechanical properties of AA5083/Silicon carbide and AA5083/Coal composites. Using a Taguchi L9 design of experiments, signal-to-noise ratio, and analysis of variance, this study identifies the optimal process settings for maximizing ultimate tensile strength, microhardness, and elongation. From the results, the study revealed that for AA5083/Silicon carbide composites, rotational speed was the most significant factor affecting tensile strength, while for AA5083/Coal composites, tilt angle played a more critical role. Rotational speed consistently influenced microhardness and elongation for both materials. The signal-to-noise ratio analysis indicates that optimal FSP parameters vary depending on the reinforcement material used. This study highlights the importance of tailoring FSP settings to specific reinforcements to achieve optimal mechanical properties. These findings contribute to the advancement of friction stir processing techniques for fabricating high-performance aluminium metal matrix composites, particularly for applications in industries requiring strong, lightweight, and corrosion-resistant materials. [ABSTRACT FROM AUTHOR]

The new generation of hybrid aluminum matrix composite was targeted to meet the yearnings of advanced engineering application which it does through improved physical, mechanical, tribological, and microstructural properties. The performance of this composite depends on the reinforcing materials selected and combined, the processing technique adopted in synthesizing the hybrid composites and processing parameters selected during the composite synthesis. This study tends to review different types of eco-friendly materials combined with synthetic materials to synthesize this new generation of hybrid composites. Perhaps, their influence on the physical, mechanical, tribological, and microstructural behavior of the synthesized composites through stir casting technique. Furthermore, research areas which could further enhanced hybrid aluminum matrix composites production with suggested enhancement were looked into for future application in engineering sector. [ABSTRACT FROM AUTHOR]

This study presents a pioneering methodology for the synthesis of aluminum matrix composites (AMCs) fortified with biochar, sourced from renewable biomass feedstocks. Employing a systematic approach, various biochar weight percentages were meticulously investigated to discern their impact on the mechanical and tribological properties of the resulting composites. Through a comprehensive battery of tests, encompassing evaluations of compressive strength and hardness, the study elucidated significant enhancements in mechanical robustness consequent to biochar integration. Notably, the mixture formulation with 7.5 wt. % biochar emerged as the optimal configuration, showcasing an impressive 8.83% augmentation in compressive strength and a notable 15% elevation in the hardness relative to the pristine aluminum pure matrix. The research extends beyond traditional analyses, introducing an exploration of tribological performance. The incorporation of biochar is anticipated to impart solid lubricating properties, influencing wear and friction characteristics. Future research directions may delve into the nuanced interplay between biochar content and tribological enhancements, offering insights into the tailored manipulation of mechanical and tribological properties in AMC through biochar reinforcement. The examination of wear and friction exhibited that the friction coefficient decreased by 6.4% when 10 wt. % of biochar was added. Furthermore, the wear resistance improved proportionally with the biochar weight percentage, regardless of the normal loads applied. The finite element model further demonstrated an enhancement in load-carrying capacity due to biochar incorporation. Finally, analysis of the texture of the rubbed surface presented that the inclusion of biochar in an AL matrix changed the way wear occurs and decreased the amount of weight lost during friction. The resulting materials not only exhibit improved mechanical strength but also hold promise for applications in industries that demand robust, environmentally conscious solutions with enhanced tribological performance. [ABSTRACT FROM AUTHOR]

High velocity oxyfuel coatings have been sprayed on aluminium (Al) alloy composites substrate with varying coating thickness and tested for their wear behavior. The density and micro‐ hardness of the coatings found to increase with increase in coating thickness. The air erosion wear test has been conducted using quartz sand of size up to 75 μm as erodent. The steady state experiments indicate that the greatest specific erosion rate is at 60° and minimum at 30°. Due to the presence of interlayer, specific erosion rate decreases with the increase in the thickness of the coatings. Surface topography of the eroded samples indicate a decrease in surface roughness with increase in impact velocity. Thereafter, Taguchi (L16) orthogonal array has been utilized in order to optimize the input parameters. Analysis of variance has been applied to determine the contribution of individual control factors. The results from Taguchi experiments and analysis of variance find the order of dominance of control factors and their individual contribution as: velocity (47.31 %) > coating thickness (29.94 %) > angle (13.26 %) > erodent feed rate (7.65 %). Coatings have exhibited a semiductile wear behavior. [ABSTRACT FROM AUTHOR]

The paper presents an analysis of the filler's effect on the machining process and on changes in the thermomechanical properties of polymer composites based on aluminum chips. Composite research samples with a polymer matrix in the form of polyamide 6 were made by the pressing method. Comparative studies were carried out on the changes in thermomechanical properties and structure of the obtained molders with different filler contents and different fractions after the machining process. In order to determine the changes in thermal and mechanical properties, analysis was carried out using the differential scanning calorimetry (DSC) method, thermal analysis of dynamic mechanical properties (DMTA) and a detailed stereometric analysis of the surface. After mechanical processing, roughness amplitude parameters and volumetric functional parameters were determined. In order to analyze the structure, tomographic examinations of the manufactured composite were conducted. In relation to the polymer matrix, a significant increase in the storage modulus of the composites was noted in the entire temperature range of the study. An increase in the enthalpy of melting of the matrix was noted in composites with a lower filler content and a shift in the melting range of the crystalline phase. Significant differences were noted in the study of the composite surfaces in the case of using fillers obtained after machining with different fractions. The dependencies of the functional and amplitude parameters of the surfaces after machining of composite samples prove the change in the functional properties of the surface. The use of aluminum chips in the composite significantly changed the surface geometry. [ABSTRACT FROM AUTHOR]

The Ti3SiC2TiSix ceramic composite was synthesized in situ from a mixture of 3Ti:1.5Si:1.2C powders under pressures ranging from 2 to 5 GPa and temperatures of 1150 °C to 1400 °C. At medium and high temperatures (4–5 GPa and 1400 °C), Ti3SiC2 dissolves into the cubic TiC phase. SEM analysis revealed that the high-pressure-produced multilayer structure of Ti3SiC2 remained intact. The friction properties of Ti3SiC2-TiSix composites combined with copper and aluminum were studied under both dry and lubricated conditions. After the break-in period, the Ti3SiC2-TiSix/Al combination exhibited the lowest friction coefficient: approximately 0.2. In dry-sliding conditions, the friction coefficient varies between 0.5 and 0.8. The wear mechanisms for Ti3SiC2-TiSix composites paired with aluminum primarily involve pear groove wear and adhesive wear during dry friction. Irregularly shaped aluminum balls accumulate in the pear grooves and adhere to each other. With increasing sintering pressure, the average friction coefficient of Ti3SiC2-TiSix composites against Cu ball pairs first increases and then decreases. The wear rate of the samples did not vary significantly as the sintering pressure increased, whereas the wear rate of Cu balls decreased with increasing sintering pressure. The adhesive wear of the Ti3SiC2-TiSix composite with its Cu counterpart is stronger than that of the Al counterpart. Abrasive chips of Cu balls appeared in flake form and adhered to the contact interface. [ABSTRACT FROM AUTHOR]

The use of inserts allows for the selective reinforcement of castings to improve mechanical properties, including surface hardness and wear rate. Metal surfaces that undergo wear on account of friction can be strengthened using metal matrix composite (MMC) inserts. An essential factor in the manufacture and application of compound casting involving MMC inserts has been the bond strength between the insert and alloy. This work studied fluxes (CsAlF4 and LiAlF4), preheating, and nickel (Ni) plating to improve the bond strength between A206 and A201-Al2SiO5 fiber MMC. It was observed that Flux 1 (G-2004), Flux 2 (CS-2020), and Ni plating, when used with preheating the insert up to 200 °C, led to the formation of a diffusion bond. The effect of fluxes and plating has been discussed, along with the impact of the insert oxide layer on the formation of diffusion bonds. The microstructure formed at the interface between casting and insert was analyzed. [ABSTRACT FROM AUTHOR]

In a comprehensive study, effects of casting methods such as gravity sand casting, squeeze casting and composite casting in semi-solid state and casting variables (i.e., cooling rate, stirring speed and shear forces) on the microstructure, porosity formation and mechanical properties of A356–SiC nanocomposites were investigated thoroughly. First, a step-like sample was used to make the sand casting samples to study the effects of different cooling rates that each step experienced on the properties of nanocomposite, where squeeze casting and composite casting samples were produced in a metallic mold. Once the samples were produced and prepared for the studies, grain size, shape factor, dendritic and globular microstructure, amount of eutectic phase and mechanism of porosity formation, mechanical properties and fracture surface of the samples were analyzed precisely and discussed. In addition, the effects of stirring forces, time and temperature, used in the squeeze casting and the compo-casting methods, on the morphology of the dendritic arms of aluminum matrix composites were investigated and compared with the microstructure of castings produced by conventional gravity casting. It was discovered that switching from the gravity sand casting process to the squeeze casting process delivers a less dendritic and more refined microstructure in the nanocomposite. However, composite castings produced in the semi-solid state by applying high stirring shear forces for 80 s produce the finest and the most globular and spherical microstructure. This optimized globularization condition provides desired microstructure and mechanical properties for this type of nanocomposite. The dominant failure mechanism in the composite casting samples produced in semi-solid state was ductile, where it was a mix of ductile/brittle for the squeeze casting and brittle for the sand casting samples. Finally, the effects of globularization temperature on the nucleation and growth of primary α grains were studied. [ABSTRACT FROM AUTHOR]

The effects of different solution temperatures on the microstructure and corrosion resistance of graphene nanoplatelets reinforced A380 (A380-GNPs) composites were investigated. The results show that the grain size of the composites was significantly refined by adding 0.9 wt% GNPs, and most of the Si phases in the A380-0.9 GNPs composite after solution treatment at 505 °C were spheroidal. Energy dispersive spectroscopy analysis indicated that most of the Al2Cu phases have been dissolved into the matrix. The hardness of the 505 °C solution treated composites increased by 28.8% compared to the A380-0.9 GNPs composites. Immersion corrosion tests revealed that the corrosion rate of the 505 °C solution-treated A380-0.9 GNPs composites (46.76 μg cm−2 d−1) was 24.9% lower than that of the non-solution-treated (58.41 μg cm−2 d−1). Electrochemical analyses showed that the corrosion voltage of the 505 °C solution-treated composites (− 507.41 mV) was 7.4% higher than that of the non-solution-treated (− 548.76 mV). The 505 °C solution-treated A380-0.9 GNPs composites had a high surface-area ratio between the anodic phases (α-Al) and the cathodic phases (Al2Cu, Si), and the anodic corrosion current densities were relatively weak, which resulted in the best corrosion resistance. The refinement and uniform distribution of cathodic phases, such as Al2Cu and eutectic Si, inhibit the occurrence of micro-galvanic corrosion and also reduce the corrosion rate of the composites. [ABSTRACT FROM AUTHOR]

The alloys and composites of 7xxx aluminum are widely used in automobile, aerospace, and other related industries due to their incredible properties, such as high specific strength, low density, and robust processing performance. In this work, mechanical and microstructural characterization of the stir-cast AA7050 metal matrix composite reinforced with TiO2 and BN is carried out by varying the weight percentages of the reinforcements. Microstructure and phase analysis of this new composite were observed with a field emission scanning electron microscopy (FESEM) and X-ray diffraction technique, while elemental analysis was performed with an energy-dispersive X-ray spectrometer. Microstructural examination of the developed composite shows that reinforcement particles are uniformly distributed throughout the matrix. The result also shows that the composite involving 2% TiO2 and 1% BN has a maximum ultimate tensile strength and a hardness value of 255 MPa and 84.2 HRB, respectively. Increasing the TiO2 content beyond 2 wt.% or BN content beyond 1 wt.% results in cluster formation, and hence the proportion of alloying elements is restricted to 2% and 1% for TiO2 and BN, respectively. Microstructural examination of fracture surfaces revealed that ductile dimples and river lines are present. [ABSTRACT FROM AUTHOR]

Aluminum metal matrix composites have gained increased interest in the automotive industry due to their high strength and thermal properties. In this research, the mechanical properties and electrical conductivity of A319 Al alloy castings with graphene additions (0, 0.05, 0.1, and 0.2 wt% additions) were investigated. The castings were carried out using hybrid semi-solid stirring and ultrasonic melt processing. The microstructure was analyzed using optical microscopy and scanning electron microscopy with energy-dispersive X-ray spectroscopy. The mechanical properties and electrical conductivity were measured via ambient temperature tensile testing and an eddy current tester, respectively. Graphene nanoplatelet additions (GNPs) effectively reduced the grain size and transformed the grains from a coarse and dendritic morphology to fine globular with improved distribution. Additionally, graphene was found to promote a reduction in Fe impurities, thereby reducing the presence of clusters of deleterious Al15(Fe, Mn)3Si2 Fe-bearing intermetallics. The tensile testing results exhibited improvements in the ultimate tensile strength (from 190 to 218 MPa) and yield strength (89–124 MPa) with graphene additions, while simultaneously maintaining good ductility (3.1–4.1%). Further, the A319/graphene composites exhibited improved electrical conductivity from 27 to 30.2% IACS. This research elucidates the mechanisms enhancing the strength and conductivity of A319 via graphene additions. [ABSTRACT FROM AUTHOR]

The present work aims to elucidate the mechanism of microstructural evolution in different regions of nano-SiC particles reinforced aluminum matrix composites prepared by friction stir processing (FSP) on its electrochemical behavior. Electron backscatter diffraction technique (EBSD) and transmission electron microscopy (TEM) were employed to characterize the microstructure evolution of stir zone (SZ), advancing side thermomechanically affected zone (AS-TMAZ), retreating side thermomechanically affected zone (RS-TMAZ) and base metal (BM). The electrochemical behaviors of the above zones were investigated using electrochemical tests. A homogeneous and fine microstructure is formed in SZ, not only the nano-SiC is homogeneously distributed within the grains with an average grain size of 3.5 μm, but also the recrystallized grains account for the highest percentage of 85 %. The potentiodynamic polarization curve indicates that the corrosion current densities of the BM, RS-TMAZ, AS-TMAZ and SZ are 0.89, 0.39, 0.85 and 0.36 μA/cm2, respectively, while the polarization impedances are 33.40, 51.42, 48.72 and 73.79 kΩ cm2, respectively. Combining the Nyquist and Bode plots analysis, the optimal electrochemical corrosion resistance is in SZ. The fine and homogeneous recrystallized grains in SZ significantly improve its electrochemical corrosion resistance. This is mainly ascribed to the increase in crystal defects as a result of the increase in grain boundaries, elevating the electron scattering. Simultaneously, the increase in high-energy state grain boundaries is beneficial to the rapid formation of a thicker passivation film. [ABSTRACT FROM AUTHOR]

The present study investigated mechanical profaties such as Young's modulus and tensile strenth of aluminum nanocomposite reinforced with defective graphene with vacancy and hole defects under uniaxial tension using molecular dynamics simulation. Also, the effect of the number of graphene layers in a constant volume ratio on the mechanical behavior of the nanocomposite has also been obtained. This simulation was done with the help of the LAMMPS open-source package by modeling a faiodic system with NVE and NPT ensembles. The AIREBO and MEAM potentials were used to describe the interaction of carbon and aluminum atoms, respectively, and Lennard Jones potential was used for the interaction between these atoms. The obtained results show that adding a single layer of graphene to the structure of pure aluminum has improved Young's modulus and tensile strenth of pure aluminum by 220 and 320%, respectively. In addition, it is observed that the effect of pinhole and vacancy defects on Young's modulus and tensile strenth is non-linear and has a decreasing trend. [ABSTRACT FROM AUTHOR]

This study aims to assess the dynamic performance of the vertical-axis wind turbine (VAWT) with the help of conventional aluminum (Al) and the boron Al metal matrix composite (MMC). The simulations were conducted using ANSYS software and involved natural frequencies, mode shapes, a mass participation factor, and Campbell plots. The results of static structural analysis show that the boron Al MMC is vastly superior to the aluminum alloy because there is a 65% reduction of equivalent stress with a 70% reduction of deformation compared to the aluminum alloy. These results show that boron Al MMC can withstand higher loads with lesser stress; the structure remains compact and rigid in its working conditions. From the findings, it can be ascertained that employing boron Al MMC improves VAWT power, efficiency, and robustness. However, the critical speed that was established in the dynamic analysis of boron Al MMC requires extraordinary control and the use of dampening systems, thereby avoiding resonance. Overall, boron Al MMC contributes to significant enhancements in the VAWTs' mechanical and operational characteristics; however, the material's complete potential can be achieved only with proper maintenance and employing the correct damping techniques. Information about these two materials will allow for a better understanding of their comparative efficacy and their potential application in the further development of VAWTs. [ABSTRACT FROM AUTHOR]

Featured Application: Towing systems are largely used in the automotive industry. They must respect some requirements defined by the standards. These important systems for cars are studied in this paper in order to improve safety in transportation. The authors present the possibility to use other materials for towbars and formulate a series of practical recommendations obtained as a result of extended studies on towing systems. This paper aims, in the context of the need to reduce the weight and price of vehicles, to present theoretical and experimental results regarding towing systems made of alternative materials (fibrous composite materials and aluminum alloys). The study of the main element of the whole system, namely towbar research, was stressed, presenting comparative results. The FEM will be used to obtain the stress and strain field in the towball and the towing system. The experimental tests validate the theoretical results obtained. This paper studies five towing systems made by different materials and finally presents a series of practical recommendations, useful in the industry, regarding the improvement of the analyzed models. [ABSTRACT FROM AUTHOR]

Gantries and beams, as the main load-bearing structures of heavy equipment, usually belong to the box structure consisting of outer walls and inner stiffened plates. The structure of the stiffener layout is bulky due to empirical design, leading to higher material consumption and impacting mechanical performance. There are challenges in effectively identifying load-transferred paths within 3D box structures through direct topological optimization. A method for optimizing the layout of internal stiffened plates of large box structures based on load paths is proposed in this paper. Initially, based on the load conditions acting on the structure, the 3D box structure is decomposed into 2D functional sections. Subsequently, the load paths on the functional cross-section are visualized according to the load path method. Finally, the stiffener layout of the ultimate optimized structure is designed according to the effective load path distribution. Taking the gantry of a heavy-duty aluminum ingot composite processing unit as an example, the optimization results indicate that the maximum stress of the structure decreased by 14.9%, the maximum deformation reduced by 32.95%, and the overall weight decreased by 14.4%. This demonstrates that the approach proposed in this paper is practical and effective for optimizing stiffener layouts in large-box structures. [ABSTRACT FROM AUTHOR]

Friction Stir Processing (FSP) has become a famous solid‐state technology for the fabrication of a wide range of aluminum alloy‐based composites that today find multiple applications across the various metal industries. Generation of revolving, ribbon, bulk, excessive or mass flash as it is generally termed has been a common problem in numerous FSP works. When confronted by this challenge, many researchers apply different experimental and numerical modeling approaches or strategies to reduce the mass flash to practically acceptable limits since it often leads to undesirable loss of material and is also an unwanted defect. This subject is deficiently reviewed, and it therefore becomes the thrust of this paper, to investigate the common trends in mass flash generation during FSP and its commonly employed reduction strategies. Mass flash is caused by high rotational speed at low travel speed and vice versa, flat shoulder, no and low tilt angles, high plunge depth, axial force, and travel force. Mass flash causes material loss, loss of volume fraction control target, material thinning, and leads to poor quality fabrications. Mass flash reduction strategies include the use of high tool tilt angles, concaved tool shoulder, proportional rotational speed and travel speed, and optimal plunge depth, axial force and travel speed as supported by both the experimental and numerical modeling studies. [ABSTRACT FROM AUTHOR]

Aluminum matrix composites reinforced with particles (PRAMCs) frequently develop considerable residual stresses post-quenching, which can negatively affect fatigue life and dimensional accuracy. Traditional stress relief methods for aluminum alloys are only partially effective. This study examined thermal stress relief (TSR), vibratory stress relief (VSR), and a combined thermal–vibratory stress relief (TVSR) approach for SiC/Al composites. All treatments proved successful in diminishing residual stresses, with the most significant reduction along the direction of peak dynamic stress. Additionally, this study analyzed micro-residual stresses via a macro–micro-residual stress finite element model to understand differences in stress relief outcomes. Optimizing the TVSR process could be key to more effectively reducing residual stresses in SiC/Al composites. [ABSTRACT FROM AUTHOR]

In this study, the MgO-coated graphene nanoplatelets (GNP)-reinforced aluminum matrix AlSi10Mg composites are fabricated by mechanical alloying and a 3D printing process. The interfacial structure of GNPs–Al has been investigated using high-resolution transmission electron microscopy, and their strengthening mechanism has been analyzed. A weak amorphous Al2O3 was found at the GNP–Al interface area in the composites made with uncoated GNPs. The structure of amorphous Al2O3 becomes distorted when load transfer is initiated, causing the detachment of GNPs from the matrix. This results in quick failure at the interface between uncoated GNPs and aluminum, restricting its overall strength. Once GNPs are coated with MgO, an Al/C mixing zone forms at the contact area, resulting in increased interface strength. The MgO coating on the GNP serves as a protective barrier, preventing the creation of a weaker amorphous Al2O3 layer at the interface and facilitating direct interaction between the GNP and Al matrix. The stress–strain curve demonstrates a 27.5% enhancement in tensile strength in the MgO-coated GNP–Al composite compared to the composite with uncoated GNPs. The strength is increased while maintaining toughness through load transmission of GNPs, bridging, and enhancing dislocation storage capacity by the Mg-rich phase. This study offers a new reference for strengthening 3D-printed aluminum alloys using GNPs. [ABSTRACT FROM AUTHOR]

In this work, fully densified Ni–SiC reinforced Ti6Al4V matrix composites were consolidated by pulsed electric current sintering (PECS) technique. The microstructural evolution and mechanical properties of the developed composites with varying SiC contents were investigated. The microstructural study revealed in-situ precipitation of TiC, Ti 5 Si 3 and Ti 3 SiC 2 strengthening phases within the composites. The α colony size in the composites was notably reduced compared to the fabricated SiC-deficient samples due to the addition of SiC additive into the Ti6Al4V alloy matrix. The in-situ precipitated phases enhanced the mechanical properties of the composites. Composite reinforced with 10 wt% SiC (TNi10SiC) displayed the highest hardness value of 609.8 ± 50.9 HV 0.5 among the sintered samples, translating to an increment of about 88 % compared to the unreinforced sample T. Among the sintered samples, the highest flexural strength of 2094.32 ± 97.67 MPa was obtained for the TNi5SiC composite, after which the flexural strength deteriorates with increasing SiC content as witnessed in TNi10SiC composite with the least flexural strength of 863.67 ± 71.57 MPa due to agglomeration of the reinforcement phases within the composite. Samples reinforced with 0 wt% SiC experienced a ductile fracture, and the composites containing 2.5 wt% - 5 wt% SiC content witnessed intergranular and interlamellar fractures. However, at higher SiC content, reinforcement pull-out and debonding of the agglomerated reinforcement phases predominates, and composites fail by brittle fracture. [ABSTRACT FROM AUTHOR]

In this study, the environmentally friendly friction stir processing (FSP) method was utilized to fabricate surface composites employing technical aluminum matrix 1050-H14 and aluminum alloy 6060-T4 reinforced with silicon carbide (SiC) particles. Microstructure analysis, employing light and scanning electron microscopy, in conjunction with comprehensive evaluations of hardness, compressive strength, and tribological properties, was conducted to elucidate significant findings. The results reveal that an augmented number of FSP passes contributes to the homogenization of microstructure, leading to the alteration of SiC particle morphology and fragmentation. Consequently, this phenomenon results in improved mechanical properties, particularly noteworthy in the case of AA6060-T4 alloy matrix composites, and enhanced wear resistance. Both AA1050-SiC and AA6060-SiC composites demonstrate notable increases in compressive strength compared to their unreinforced matrices. Particularly noteworthy is the substantial enhancement in compressive strength observed in the AA6060-SiCp composite, escalating from 249 to 331 MPa (at ε = 0.1) and from 398 to 715 MPa (at ε = 0.2) with an increase in the number of FSP passes. Additionally, FSP's ability to precisely control process parameters such as tool rotational speed and traverse speed allows for the optimization of mechanical properties and microstructural characteristics tailored to specific application requirements. This study highlights the potential of FSP in fabricating high-performance aluminum matrix composites with superior strength and wear resistance, positioning it as a viable technique for advanced engineering applications. The environmentally friendly nature of FSP, due to its solid-state operation and reduced energy consumption, further underscores its suitability for sustainable manufacturing practices. [ABSTRACT FROM AUTHOR]

In this work, we use a simple and efficient method to introduce "TiO 2 –Al" interfacial layers between the B 4 C particles and aluminium (Al) matrix in TiO 2 @B 4 C/Al composites by combining the ball milling dispersion process with the pressure infiltration technology. It is anticipated that it would improve the mechanical properties and corrosion resistance. The work demonstrates that the coefficient of thermal expansion (CTE) of the "TiO 2 –Al" interfacial layer is between those of the matrix and the reinforcement. Thus, it relieves the residual stresses in the composites. Furthermore, the low residual stress of the composites achieved by introducing the "TiO 2 –Al" interfacial layer results in delayed failure and the low corrosion tendency. The composites containing "TiO 2 –Al" interfacial layers show remarkable bending properties (a strength of 668.6 MPa) and good corrosion resistance (a low corrosion current density of 6.81 μA cm−2). Thus, the TiO 2 @B 4 C/Al composites exhibit remarkable mechanical properties and corrosion resistance compared with the composites reported in the literature. [ABSTRACT FROM AUTHOR]

Al6061 alloy has become prevalent in the industrial sector because of its low density, excellent machinability, and corrosion resistance but it lacks properties like hardness and wear. Therefore, surface modifications by friction stir processing (FSP) are done with additive nanosized particles like multi-walled carbon nanotubes (MWCNT), Titanium oxide (TiO2), and Graphene nanoparticles (GNP) To perform 2-pass FSP, a uniquely engineered fixture with coolant circulated underneath the plate at sub-zero temperatures is used. Grain refinement has been observed in micrographs as a consequence of 2-pass FSP. The coolant circulated beneath carries the heat generated and enhances the heat dispersion rate, culminating in finer grains. The calculated mean grain size of the Al6061 alloy was considerably decreased in all the surface composites. There is a substantial improvement in the microhardness profile, which has increased by nearly 70–90%, as well as a significant enhancement in tensile strength of almost 20–30% in all the composites. The ductile type of failure during tensile load is revealed by SEM fractography. The process of dynamic recrystallisation is responsible for the development of equiaxed grains. The wear resistance of all the composites is also enhanced, and the COF of Al6061/GNP composite is found to be lowest at 0.23. [ABSTRACT FROM AUTHOR]

Low-cost amorphous nano-carbon (ANC) was employed as an absorbent to modify the microwave performance of AlN ceramics (AlN-4 wt% Y 2 O 3 - x wt% C, x = 0, 2.0, 3.8, 3.9, 4.0) via hot-pressing sintering, and the thermal and mechanical properties were also investigated. With the increase of ANC content from 0 to 4.0 wt%, the relative density of AlN composite decreases from 3.28 g cm−3 to 3.16 g cm−3 when sintered at 1800 °C for 2 h, and with the increase of sintering temperature from 1700 °C, the density of the 4.0 wt% ANC doped AlN composite presents trend of increase and reaches the maximum value of 3.16 g cm−3 at 1800 °C and then decreases. The XRD pattern shows that the composites are composed of AlN and Y–Al–O (YAG, YAP, YAM et al.) phases. SEM results indicate that average grain sizes for AlN and secondary phases gradually decrease with increasing carbon content, suggesting inhibited grain growth due to ANC addition. No obvious changes in phase constitution nor intensity changes were detected with the increase in carbon content and sintering temperature. As the carbon content increases from 0 to 4.0 wt%, the dielectric constant gradually increases from ∼9 to 13.89 at 10 GHz, the dielectric loss gradually increases from the vicinity of 10−3 to 0.38 at 10 GHz, and the reflective loss decreases from −27.92 dB to −49.40 dB, the thermal conductivity of the AlN-ANC composite decreases from 116.63 W m−1 K−1 to 50.13 W m−1 K−1. In addition, with 4.0 wt% ANC addition, the dielectric constant, dielectric loss, reflective loss, hardness, elastic modulus, bending strength, and fracture toughness are 13.89, 0.38, 49.40 dB, 6.4 ± 0.4 GPa, 262 GPa, 268.78 MPa, and 1.4 ± 0.1 MPa m1/2, respectively. Its ability to efficiently absorb microwave energy enhances the performance of devices including radar systems, communication equipment, and microwave heating systems, making it a promising candidate for microwave vacuum electronic applications. [ABSTRACT FROM AUTHOR]

Aerospace and automotive industries, among others, utilize reinforced aluminium metal matrix composite materials extensively. Aluminium alloy 5052 matrix was reinforced with tungsten carbide and titanium dioxide particulate reinforcements by varying their weight fractions, to fabricate the hybrid composites. The melt‐stir casting route was used to process the materials, and their characteristics were determined by measuring Vickers microhardness, tensile strength and peak elongation. The cost‐effectiveness and productivity of the melt‐stir casting route led to its selection. Investigations were carried out to assess how reinforcement particles were mixed into the aluminium alloy matrix using scanning electron microscopy and energy‐dispersive x‐ray analysis. The microstructure of aluminium alloy 5052 showed a distinct homogenous structural integrity. Adding tungsten carbide and titanium dioxide particles to aluminium alloy 5052 led to a 6.57 % rise in the Vickers microhardness value. The tensile strength of the hybrid composites made of aluminium, tungsten carbide, and titanium dioxide increased by as much as 8.7 %. The findings demonstrated that all of the hybrid composites failed due to particle fracture and ductile fracture in the case of the as‐cast aluminium alloy 5052. [ABSTRACT FROM AUTHOR]

In this paper, three‐phase composites were made by combining N220 carbon black rubber powder with open‐cell aluminum foam and epoxy resin with mass fractions of 3 %, 5 %, and 7 %, respectively. The mechanical and energy absorption properties of three groups of epoxy resin/rubber powder/aluminum foam three‐phase composites with added aluminum foam and different mass fractions of N220 carbon black rubber powder were analyzed during quasi‐static compression at a compression rate of 2 mm/minute. The mechanical parameters in the quasi‐static compression experiments were compared with those of the two‐phase composites of epoxy resin/rubber powder with no added aluminum foam. Finally, the micro‐morphology of the composites after quasi‐static compression damage was observed by scanning electron microscopy. The results show that the collapse deformation of aluminum foam during compression affects the stability of the epoxy resin/rubber powder composite matrix and reduces the toughness of the epoxy resin/rubber powder composite matrix. [ABSTRACT FROM AUTHOR]

The motto of research is to attempt to enrich the mechanical and fracture resistance quality of AA5052 alloy composite composed by the adaptations of 0, 3, 6, and 9 weight percentages (wt%) of silicon carbide (SiC) nanoparticle and 5 wt% of chopped E-glass fiber through vacuum-assisted stir processing under 500 rpm. The metallography analysis of composite samples is analyzed and spots the good interfacial with void-less structure. The composite's mechanical and fracture qualities enriched through the inclusion of SiC (9 wt%) / E-glass fiber (5 wt%) in AA5052 alloy composite attained the highest tensile strength, better hardness, improved elongation percentage and excellent fracture toughness, which is enhanced by 25.5, 33.8, 22, and 15 % comparable to the value of monolithic AA5052 alloy cast. The E-glass configured hybrid AA5052/SiC alloy composite is suggested for automotive body structural applications. [ABSTRACT FROM AUTHOR]

The mechanical properties and structure of polybutylene terephthalate (PBT)/aluminum (Al) composite prepared by ultrasonic-assisted hot-pressing were analyzed, and the influence of ultrasonic-assisted on the bonding properties of PBT/Al composite was studied. The experimental results showed that under the optimal ultrasonic-assisted conditions, the tensile shear strength of the PBT/Al composite reached 26.55 MPa, which was 22.18% higher than that of the PBT/Al composite without ultrasonic-assisted (21.73 MPa). Scanning electron microscopy (SEM) showed that during the hot-pressing process, ultrasonic-assisted promoted the embedding of PBT in the anodic oxide pores on the surface of Al, forming a stronger mechanical interlocking structure. X-ray diffraction (XRD) showed that ultrasonic-assisted did not change the crystal type of PBT, but the shear effect of ultrasound affected the arrangement and orientation of molecular chains in the PBT melt, resulting in changes in crystallinity. X-ray photoelectron spectroscopy (XPS) showed that ultrasonic-assisted did not generate new chemical bonds during the hot-pressing process. Therefore, during the hot-pressing process, ultrasonic-assisted promoted the embedding of PBT in the anodic oxide pores on the surface of Al, enhanced the mechanical interlocking effect between PBT and Al, and improved the tensile shear strength of the PBT/Al composite. [ABSTRACT FROM AUTHOR]

A micromechanical model with realistic initial fiber misalignment (IFM) was developed to simulate the longitudinal compression behavior of unidirectional carbon fiber/aluminum composites. The matrix and fiber were modeled using ductile damage law and brittle fracture model, respectively. The interfacial properties were firstly determined by the single‐fiber push‐out and transverse tensile tests, and the cohesive zone model was adopted to capture the interfacial behavior. The calculated compressive response curve is in alignment with the experimental data. Compression failure can be attributed to fiber kinking, possibly triggered by the matrix shear damage. The increase of IFM angle makes the failure mode being transformed from fiber crushing to fiber kinking, along with a significant decrease in compressive strength. With the fiber content increasing, the compressive strength increases first and then decreases, while the compressive modulus increases monotonically. Increasing interfacial strength significantly improves the compressive strength, but this is limited by the matrix properties. Highlights: Micromechanical modeling with realistic fiber misalignment of UD‐Cf/Al composites.Identifying interface parameters via single‐fiber push‐out tests and numerical methods.Experimental and numerical investigation into longitudinal compression failure process.Effects of misalignment, fiber fraction, and interface strength on compressive behavior. [ABSTRACT FROM AUTHOR]

This study investigates the corrosion resistance and wear behaviour of aluminium matrix composites (AMCs) manufactured through the ultrasonic-assisted stir-casting technique. These composites were synthesized by introducing titanium carbide (TiC) and nickel (Ni) into aluminium alloys (AA6061). The X-ray diffraction results confirmed the presence of α-Al, TiC and Al3Ni phases within the composites. Microstructural examination demonstrated an uniform dispersion of TiC particles and dispersion of Al3Ni along grain boundaries. To evaluate the corrosion behaviour, samples were subjected to immersion tests and electrochemical techniques, including potentiodynamic polarization and electrochemical impedance spectroscopy (EIS), in a 3.5 wt% NaCl solution. Immersion tests indicated that the composites exhibited slower dissolution rates than base AA6061 alloys. Potentiodynamic polarization results revealed that the inclusion of TiC and Ni reinforcements enhanced corrosion resistance, with TiC having a more pronounced influence. The EIS tests suggested that the composites had higher charge-transfer resistance than AA6061 alloys. After conducting corrosion tests, scanning electron microscope (SEM) images of the base AA6061 alloys unveiled the presence of deep pits but the inclusion of reinforcements resulted in the shallow pits. In addition, Vickers hardness tests and pin-on-disc wear tests were conducted to investigate hardness and wear properties. Notably, hybrid composites containing 3% TiC and 3% Ni exhibited a substantial 42.18% increase in hardness as compared to the base alloy. These hybrid composites also demonstrated superior wear resistance, with a wear rate that was 58.6% lower compared to AA6061 alloy and 41% less than that of the 3% Ni-reinforced composite. [ABSTRACT FROM AUTHOR]

Lightweight metal matrix composites made of aluminium are now essential in several fields, including aerospace and automotive. An important factor determining the quality and properties of the composite material is the ease or difficulty of evenly dispersing the reinforcement throughout the matrix. The goal of this research is to find out the impact of 40 and 90 µm varyingsized boron carbide (B4C) particles in A356 alloy composites. Using the liquid stir casting technique and K2TiF6 as the wetting flux, A356 alloy with 9 wt.% of B4C composites were prepared. SEM and EDS images were used to study the material's microstructure. ASTM-approved methods were used to measure the material's mechanical properties. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) confirmed that B4C particles were evenly distributed throughout the A356 alloy. The addition of B4C reinforcement to the A356 alloy matrix increased the hardness, ultimate, yield, compression, and impact strength of composites with a reinforcement size of 40 μm. The hardness of A356 alloy was enhanced by 40.7% and 34.6%, respectively, when 9 wt. % of 40 and 90 μm B4C were added. Similarly, there was a 34% increase in ultimate strength and a 31% improvement in yield strength. Both cases showed a little decrease in the ductility of the composites. Scanning electron micrographs were used to examine the morphologies of tensile fractured surfaces. [ABSTRACT FROM AUTHOR]

The paper presents the results of research on the production of cast composites based on aluminum alloys with a mineral filler with a porous structure. AlSi12 silumin and AlSi12 silumin with the addition of 3% magnesium (AlSi12-Mg3) were used as the matrix material, while particles of natural zeolite, expanded perlite and expanded clay with a size of 4 to 6 mm were used as the mineral filler. In order to increase the efficiency of the production process, the mineral particles have been covered with a sodium silicon solution with the addition of silicon powder. The coated particles were then heated at 400 ℃ for 1 hour to remove moisture from them. The prepared mineral particles were then placed inside a casting mold and flooded with liquid alloy at a temperature of 790 ℃. The obtained composites were subjected to macroscopic observations and analysis using computed tomography (CT). Phase analysis was also performed to determine the phase composition of the obtained composites. In order to determine the mechanical and physical properties, the obtained composites were subjected to compressive strength tests and density measurements. As a result of the research, it was found that the use of the AlSi12-Mg3 alloy and coating in the form of a solution of sodium silicate and silicon powder allows for the most effective production of composites. The low density of the produced composites, combined with their favorable structure and strength properties, suggest the possibility of use as light products transferring compressive stresses, as well as energy-absorbing products. [ABSTRACT FROM AUTHOR]