Dispersed Al2O3 Research Articles

Tensile and corrosion properties of copper and alumina hybrid reinforcement on aluminum matrix composite

Aluminum composites are widely used in aviation, space, automotive, and marine applications due to their excellent properties, including high strength and strong resistance to corrosion. This study investigates the microstructure, mechanical properties, and corrosion behavior of aluminum matrix composites (AMCs) reinforced with alumina (Al₂O₃) and copper (Cu) particulates, aimed at enhancing the material’s structural performance for potential engineering applications. Composite samples were prepared via double stir casting, utilizing varying ratios of Al₂O₃ and Cu. Microstructural analysis revealed uniform dispersion of Al₂O₃ in the aluminum matrix, promoting grain refinement and improved load-bearing capability, while Cu particles contributed to enhanced ductility by forming Al-Cu intermetallic phases. The addition of Al₂O₃ notably improved the composites’ hardness and tensile strength, whereas Cu increased ductility but led to reduced corrosion resistance due to galvanic effects between Al and Cu phases, especially in saline environments. Corrosion testing indicated that Cu-reinforced samples displayed a comparatively higher corrosion rate. These findings underscore the promise of Al₂O₃-reinforced AMCs for applications requiring improved mechanical strength and durability, while Cu reinforcement could be tailored for applications needing enhanced ductility. This research provides insight into designing AMCs with specific property trade-offs and advancing material options for the automotive and marine engineering industries.

Experimental analysis of mechanical properties and FTIR analysis of areca fiber-reinforced epoxy composites incorporating Al2O3

The interest in natural fiber reinforced polymer composites is rapidly growing in terms of both industrial and domestic applications. The present study is an attempt to improve the mechanical properties of composites made of areca fiber and epoxy resin with the incorporation of alumina filler. The filler was added in various percentages (0wt%, 2wt%, 4wt%, 6wt%, 8wt %) and the composite fabrication was done by compression molding technique. The fabricated composites were tested for tensile, hardness and impact properties. The results demonstrate that 8wt%Al2O3-A-E composite shows superior (tensile, impact, Hardness) mechanical composites. For improvement of hardness and strength main contributing factors were uniform dispersion of Al2O3 (Aluminum oxide) particles and better load transfer between Al2O3 (Aluminum oxide) particles and epoxy matrix. The effect of alkaline treatment of areca of fibers was verified by FTIR analysis. The experimental investigation attempt to improve the Areca epoxy composites by loading fillers and for the applications of light weight and high strength components in different sectors like aerospace and automobiles. Fracture surfaces were analyzed using Scanning Electron micrograph (SEM).

Novel sol-gel derived layered double oxides and layered double oxide/γ-Al2O3 with tunable selectivity as promising adsorbents for L-lactate uptake from the myoblast culture medium

Cultured meat production, a biotechnological solution for global protein demand and sustainability, faces economic challenges due to the high demand for cell culture medium. Contamination with cell metabolites, particularly L-lactate, impedes myoblast proliferation in high-density suspension culture. Eliminating L-lactate is crucial for reusing the medium and overcoming economic barriers in mass myoblast culture. Retaining essential nutrients like D-glucose, amino acids, and vitamins after L-lactate removal is imperative for sustained myoblast growth. This study proposes a sustainable and economically feasible adsorption technique utilizing novel sol-gel derived Mg-Al layered double oxides and Mg-Al layered double oxide/γ-Al2O3 with tunable selectivity as a promising tool for L-lactate uptake from the myoblast medium. In an aqueous solution, L-lactate uptake and selectivity over D-glucose were enhanced with the decrease in total Mg/Al ratio and crystallinity, increase in Al2O3 dispersion in adsorbent, specific surface area, and porosity. The latter was achieved successfully by metal alkoxide sol-gel method employing an organic structure-directing agent, where LDO/amorphous alumina nanohybrid with Mg/Al = 1.23 was successfully prepared in mixed methanol-ethanol solution in a relatively short time. A simple mixture of Mg-Al LDO with Mg/Al = 2 and nano-γ-Al2O3 prepared by a sustainable and economically feasible co-precipitation method was found to have comparable efficiency and selectivity to a costly sol-gel derived material. In myoblast medium, lower total Mg/Al was associated with higher cytocompatibility, pH-stability, and selectivity, while surface properties of materials did not play a significant role. Nano-γ-Al2O3 was identified as the most promising material for selective L-lactate uptake from the myoblast culture medium. Thus, further optimization of the medium treatment process with nano-γ-Al2O3 can realize cost-effective high-density myoblast culture with circular use of the medium – a novel sustainable process in the biotechnology field.

Effect of Nanosized Al2O3 Dispersion on the Structural and Electrochemical Properties of PMMA/TEGDME-Based Mg-Ion Conducting Polymer Gel Electrolyte

Effect of Nanosized Al2O3 Dispersion on the Structural and Electrochemical Properties of PMMA/TEGDME-Based Mg-Ion Conducting Polymer Gel Electrolyte

Favorable formation of needle-shaped NiAl2O4 phase over macroporous Ni/CexZr1-xO2–Al2O3 catalysts in one-pot preparation and coke-resistant catalytic performance in dry reforming of methane

In this study, we report the formation of needle-shaped NiAl2O4 via favorable interactions between Ni and Al species over macroporous Ni/CexZr1-xO2–Al2O3 catalysts for dry reforming of methane (DRM) and its remarkable improvement in the catalytic performance. The macroporous catalysts prepared by a one-pot (OP) method promote a favorable interaction between Ni and Al species that results in the formation of unique needle-shaped NiAl2O4 due to easy access to each other compared with that by incipient wetness impregnation. The NiAl2O4 phase in the calcined catalysts transforms into highly dispersed Ni and defective Al2O3 via the Ni exsolution in the reduction step. The presence of oxygen vacancies near Ni0 species facilitates the CO2 activation and enhances the catalyst stability over DRM. The optimized distribution of active sites with abundant defects over macroporous Ni/CexZr1-xO2-Al2O3 catalysts (OP) result in high conversions of CH4 and CO2 and a low coking rate in DRM.

Investigations on Mechanical Properties of Nano Particulates (Al<sub>2</sub>O<sub>3</sub>/B<sub>4</sub>C) Reinforced in Aluminium 7075 Matrix Composite

Metal Matrix Nano Composites (MMNCs) with the addition of nano-particulate reinforcements can be of significance for automobile, aerospace, and numerous applications due to their low density and good mechanical properties, better corrosion and wear resistance, low coefficient of thermal expansion as compared to conventional materials. Designing the metal matrix composite material aims to combine the desirable attributes of metals and ceramics. The present work is focused on studying the mechanical properties of aluminium alloy (7075) with Al2O3 and B4C nanocomposite produced using the stir casting technique and ultrasonic cavitation method. Different % age of reinforcement is used. An ultrasonic cavitation technique is used to achieve a uniform dispersion of nano-particulate Al2O3 and B4C in molten aluminium alloy. Tensile, Hardness, and Impact tests were performed on the samples obtained by the fabrication processes. A structural study will be carried out through a Scanning Electron Microscope (SEM) to know the distribution of Al2O3/B4C Nano particulates in Al alloy.

The Nanoparticle-induced Zener Pinning Effect on Strain-softening in a Cold-Worked Cu-Al2O3 Composite with 0.1 wt.% Al Content

The thermo-stability of microstructure during isothermal annealing at 900 °C and 1000 °C in a cold-worked Cu-Al2O3 composite with 0.1 wt.% Al content and its effect on resistance to softening were investigated in this paper. The results reveal that the microstructure following cold deformation consists of a Cu matrix with a refined grain size and high-density dislocations, accompanied by dispersed Al2O3 nanoparticles exhibiting an extremely low volume fraction. During isothermal annealing at 900 °C, the Al2O3 nanoparticles can strongly restrict the migration of the dislocations and suppress the recrystallization of the fine-grained Cu matrix by the Zener pinning effect. Furthermore, the presence of pinned dislocations facilitates the formation of sub-grain boundaries comprising high-density dislocations. Consequently, the Cu-Al2O3 composite with 0.1 wt.% Al content exhibits remarkable thermo-stability in its microstructure due to the incorporation of Al2O3 nanoparticles, resulting in a significantly elevated softening temperature of up to 1000 °C and thereby demonstrating excellent resistance against softening. However, the observed phenomenon of softening after isothermal annealing at 1000 °C for 5 hours can be attributed to extensive recrystallization growth that promotes twin boundary formation, primarily caused by the weakening Zener pinning effect resulting from Oswald ripening of Al2O3 and rod-like Al2O3 formation.

Depriving friction stir weld defects in dissimilar aluminum lap joints

The contemporary automotive industry increasingly incorporates composite materials and innovative joining techniques to meet customer demands for lightweight, high-strength alloys. This research explores the feasibility of using friction stir welding (FSW) methods to fabricate dissimilar aluminum nanocomposite lap joints, integrating Al2O3 nanoparticles into the weld nugget. Lap joints were prepared with varying tool rotation speeds (1000–1600 rpm) and the mechanical and metallurgical behaviors of AA6061–AA7075-T6/Al2O3 lap joints were examined. The inclusion of filler material in the weld joint resulted in an 18% increase in shear strength compared to joints without filler. Dynamic crystallization impeded grain boundaries and reduced grain size in the weld stir zone (SZ), with the most enhanced mechanical characteristics observed at a tool rotation speed of 1400 rpm. The shear strength at 1400 rpm was 5780 N, representing a 17% increase compared to joints prepared at 1000 rpm. Field emission scanning electron microscopic examination revealed evenly dispersed Al2O3 nanoparticles within the weld zone, supporting the lap shear test results. Notably, joints created at lower (1000 rpm) and higher tool rotational speeds (1600 rpm) exhibited brittle fracture behavior. The addition of Al2O3 significantly improved lap joint tensile strength due to its uniform dispersion in the SZ. Increasing the FSW tool rotational speed from 1000 to 1400 rpm facilitated nanoparticle dispersion, further enhancing lap joint strength.

Effect of Copper Powder Addition on Microscopic Deformation Behavior of Al2O3/Cu‐Dispersion‐Strengthened Copper‐Sintered Billet

In this work, it is aimed to improve the deformation ability of the Al2O3 dispersion strengthened copper sintered billet by building heterogeneous structure with addition of different sizes of particle. Using the modified mixture model and equal work law, the stress distribution model of heterogeneous materials is derived. In the results, it is shown that higher deformation temperature and lower strain rate are conducive to steady deformation. Under the conditions of 950 °C and 0.01 s−1, the stress distribution coefficients from low to high are 10, 25, and 5 μm, respectively, when the strain is 0.1. The strain contribution rates of softness of the sintered billet are 45.5%, 62.1%, and 42.6%, respectively. The addition of 10 μm particle size copper powder can significantly improve the deformation capacity of the sintered billet. It is found that with the increase of the particle size of copper powder, the density of the microgeometrically necessary dislocation of the hot extrusion dispersed copper is lower. The reason is that the different particle size of copper powder leads to the different distribution in powder stacking, which affects the difficulty of harmonizing the deformation of soft and hard and the number of dislocation in the hot‐extrusion process of sintered billet.

Flexible self-supporting inorganic nanofiber membrane-reinforced solid-state electrolyte for dendrite-free lithium metal batteries.

Compounding of suitable fillers with PEO-based polymers is the key to forming high-performance electrolytes with robust network structures and homogeneous Li+-transport channels. In this work, we innovatively and efficiently prepared Al2O3 nanofibers and deposited an aqueous dispersion of Al2O3 into a membrane via vacuum filtration to construct a nanofiber membrane with a three-dimensional (3D) network structure as the backbone of a PEO-based solid-state electrolyte. The supporting effect of the nanofiber network structure improved the mechanical properties of the reinforced composite solid-state electrolyte and its ability to inhibit the growth of Li dendrites. Meanwhile, interconnected nanofibers in the PEO-based electrolyte and the strong Lewis acid-base interactions between the chemical groups on the surface of the inorganic filler and the ionic species in the PEO matrix provided facilitated pathways for Li+ transport and regulated the uniform deposition of Li+. Moreover, the interaction between Al2O3 and lithium salts as well as the PEO polymer increased free Li+ concentration and maintained its stable electrochemical properties. Hence, assembled Li/Li symmetric cells achieved a cycle life of more than 2000 h. LFP/Li and NMC811/Li cells provided high discharge specific capacities of up to 146.9 mA h g-1 (0.5C and 50 °C) and 166.9 mA h g-1 (0.25C and 50 °C), respectively. The prepared flexible self-supporting 3D nanofiber network structure construction can provide a simple and efficient new strategy for the exploitation of high-performance solid-state electrolytes.

Studies on thermal stability, softening behavior and mechanism of an ADS copper alloy at elevated temperatures

An Al2O3 dispersion strengthened (ADS) alloy with an ultra-high softening temperature of ∼1200 K was fabricated by the in-situ internal oxidation and reduction methods. The evolution of the nanometer Al2O3 particles, grain size, and consequently the softening behavior of this ADS alloy, were investigated by conducting the annealing treatments in the range from 673 K to 1273 K for 60 min. These refined nanometer Al2O3 particles were found to be highly stable at elevated temperatures, leading to the high dislocation density and grain boundary stability of the matrix. The average grain size was found to increase extremely slowly from ∼0.60 μm to ∼0.74 μm with increasing annealing temperatures from 773 K to 1273 K. A criterion for grain boundaries migration and softening was established based on the competition between grain growth and pinning effect of Al2O3 particles. The strong pinning effect of Al2O3 particles was found when the grain size was between the lower limit (about 0.4–0.5 μm) and upper limit (2.18 μm). The occurrence of softening behavior was attributed to the rapid increase of the proportion of grains larger than the upper limit. A modified Hall–Petch relationship was established by introducing the integration of the grain size distribution, which can describe this correlation between softening behavior and the pinning effect of Al2O3 particles. The current study not only sheds light on the further understanding of the softening mechanism of ADS copper alloy but also provides a useful route for designing copper alloy with high softening resistance.

Effect of P and Ti on the agglomeration behavior of Al2O3 inclusions in Fe–P–Ti alloys

Abstract Nozzle clogging occurs in the interstitial free (IF) steel with high phosphorus (P) more frequently than in IF steel with lower P. To explore the effect of P and Ti on the inclusion behavior in liquid steel, the in situ experiment and theoretical calculations were conducted. High-temperature confocal laser scanning microscopy was used in situ to observe the inclusion behavior at the liquid Fe–P–Ti alloy surfaces, and the attractive and capillary forces were also calculated to quantitatively estimate the effect of P and Ti on the inclusion behavior. The results show that the agglomeration of Al2O3 inclusions involves four steps: dispersed Al2O3 particles in liquid alloy; formation of Al2O3 chain structure; bending of the Al2O3 chain, and sintering and densification of the chain structure. The addition of Ti and P in the steel can increase the agglomeration time of inclusions, indicating the impeding effect of P and Ti on the inclusion aggregation. Furthermore, the orientation factor is proposed to estimate the direction of movement of the small inclusion crossing between large inclusions, and the experimental results confirm its validity.

Computational investigation of homogeneous-heterogeneous reactions in fluid with transport mechanisms: A finite element simulations approach

There are numerous applications in engineering and industry for homogeneous and heterogeneous chemical reactions in fluid regimes under the influence of nanoparticles and hybrid nanoparticles. This article models homogeneous and heterogeneous chemical reactions in the flow of polymer liquid (glycerin) containing Cu-Al2O3 in the presence of heat and mass transfer. The finite element method is used to quantitatively solve these models. A 76% increase in wall shear stress for the case of simultaneous dispersion of Cu and Al2O3 in comparison of only dispersion of Cu is noticed. Similarly, 44% increase in wall heat flux in noticed due to dispersion Cu and Al2O3 in comparison of dispersion of Cu only. The vortex parameter is responsible for a significant increase in the macro-motion of the fluid particles. Macro-motion gets more influence of micro motion than the influence of micro-motion on the macro-motion of Cu-Al2O3- polymer. To control momentum boundary layer thickness, reduce the diameter of the circular pipe. Magnetic force has the opposite direction of flow. Therefore, fluid motion is a decreasing function of magnetic field intensity. Further, the Lorentz force (magnetic force) for the case of Cu-Al2O3 - polymer is stronger than that for the case of Cu- polymer. Additionally, it can be seen that Cu-Al2O3- polymer experiences more Joule heating than Cu- polymer does. The micromotion is compromised when the curvature parameter is increased. As a result, convective transport slows down and the temperature of Cu- polymer and Cu-Al2O3 - polymers decreases. The result, the rate of conversion of electrical energy into heat speeds up intensity of magnetic field increase as and therefore, fluid temperature increases.

Severe plastic deformation induced nano dispersion and strengthening effect in oxide dispersion strengthened copper fabricated by cold spray additive manufacturing

This work presented a novel net-shape-forming technology to prepare oxide dispersion strengthened (ODS) copper by cold spray additive manufacturing. There were three types of Al2O3 particles in the internal oxidation Cu-Al2O3 raw powders. After cold spraying, two types of nano-sized Al2O3 inside the raw powder were inherited into the deposition, and the micro-sized Al2O3 on the powder surface was crushed to nano-size under severe plastic deformation, which dispersed along the interface of deformed powder due to the plastic flow of Cu caused by adiabatic shearing. The plastic deformation produced by cold spraying was 20% higher than the hot extrusion with extrusion ratio of 11:1, which fully achieves the Al2O3 fragmentation, dispersion distribution and densification of the cold sprayed deposition. Moreover, due to the significant work hardening and grain refinement effect by SPD during cold spraying, Vickers hardness and nanoindentation hardness of the ODS Cu deposition increased to 185.63 HV3 and 2.76 GPa, respectively, which were significantly higher than the raw powders and hot extrusion sample.

Investigations On Mechanical Properties Of Micro Particulates (Al2O3/B4C) Reinforced In Aluminium 7075 Matrix Composite

Metal Matrix Micro Composites (MMMCs), with the addition of micro-particulate reinforcements, can be significant for automobile, aerospace and numerous applications due to their low density and good mechanical properties, better corrosion and wear resistance, and low coefficient of thermal expansion compared to conventional materials. Designing the metal matrix composite material aims to combine the desirable attributes of metals and ceramics. The present work is focused on studying the mechanical properties of Aluminium alloy (7075) with Al2O3 and B4C micro-composite produced by the Stir Casting method. Different % age of reinforcement is used. The Stir casting technique is used to achieve a uniform dispersion of micro-particulate Al2O3 and B4C in molten aluminium alloy. A tensile test, Hardness test, and Impact test were performed on the samples obtained by the fabrication processes. A microstructural study will be carried out through an optical Microscope to know the distribution of Al2O3 and B4C micro particulates in Al alloy.

Nanocrystalline Ag–Cu–Al Alloy thin films with densely dispersed alumina particles prepared using reactive sputtering method with Ar–O2 mixed gas

As a first step to challenge the fabrication of highly O2-permeable Ag membranes, thin films of nanocrystalline Ag–Cu–Al alloys with densely dispersed Al2O3 particles were successfully prepared via reactive sputtering using Ar–O2 mixed gas. The effect of O2 partial pressure on the thin film structure during sputtering was investigated. A critical O2 partial pressure was required to obtain a nanocrystalline structure via simultaneous internal oxidation during sputtering. The critical condition was correlated with the flux ratio of O2 to Al impinging on the Ag film surface and the stoichiometric ratio of O to Al in Al2O3.

Promising Directions in Chemical Processing of Methane from Coal Industry. Part 2. Development of Catalysts

For the creation of new highly active and stable catalysts for the complete processing of coal methane, different methods for designing catalytic systems are being applied, including the use of the effects of mutual strengthening of the action of metals and modifying the composition of the supports. Different chemical synthesis approaches were considered for obtaining supported Ni nanoparticles with controllable compositions and sizes. For the citrate sol-gel method, it was found that with an increase in the citric acid/metals molar ratio from 0 to 1, the textural characteristics (specific surface area: 76→100 m2/g) of Сe0.2Ni0.8O1.2/Al2O3 catalysts, dispersion (average particle size: 10→5 nm) and reducibility (temperature of maximum H2 consumption: 580→530 °C) of the Ni-containing species improved. For calcined in air at 500 °C catalysts it was shown that Ni2+ cations stabilized in NiO or in the Ce-Ni-O solid solution. The proportion of the latter was maximum at a citric acid/metal molar ratio equal to 0.25, which was chosen as the optimal value in the investigated range of 0.25–1.0. An increase in the calcination temperature from 500 to 900 °C contributes to the stabilization of Ni2+ in the Al-Ni-O solid solution, which leads to a slight deterioration in the textural properties of the samples and a significant difficulty in their reducibility. After reductive activation at 800 °C of Сe0.2Ni0.8O1.2/Al2O3 samples, catalytically active metal Nio nanoparticles of ~7 nm in size were formed for effective reforming of coal industry methane into synthesis gas.

Analysis of microstructure evolution and deformation mechanism of nano-oxides Al2O3 dispersion strengthened copper alloy during compression at room temperature

The refinement of grains to the size of ∼ 600 nm is observed in a nano-scaled Al2O3 dispersion-strengthened (ODS) Cu alloy under compression distortion. The plastic deformation mechanism of the ODS Cu alloy is studied by the observation and analysis of the evolution of grain size, dislocation density and distribution, and texture orientation during compression process. The deformation process can be divided into four stages, i.e., leaner deformation stage, plastic-strengthening transition stage, relative steady state stage and softening stage under ∼ 90 % compression, according to the stress-strain curves. The grains are found split into refined sub-grains by the net-like entangled dislocations due to the pinning effect of nano-scaled Al2O3 particles. The dislocation density of ODS Cu is found increasing within 30 % compression, and then remaining to a plateau under ∼ 30 %−60 % compression, but then under ∼ 60 %−80 % and ∼ 80 %−90 % compression, the dislocation density increases firstly and then decreases. The crystal orientation is transformed from the Goss texture {110}< 001 > to the inhomogeneous Shear texture {001}< 110 > during the compression process, due to the rotation of grains. This study provides a further understanding of the strengthening mechanism and a guidance for the design of ODS Cu alloys, which is significant for the prospective future structural applications.

Hexamethylene diisocyanate-modified Al2O3 as inorganic fillers enabling low resistance and high stable cross-linked polymer electrolyte of lithium metal batteries

In this work, we first utilized hexamethylene diisocyanate-modified Al2O3 as inorganic fillers to construct a double-network solid polymer electrolytes based on the interpenetrated poly(vinylidene fluoride) and poly(ethylene oxide) (PEO@PVDF). The hexamethylene diisocyanate can promote the uniform dispersion of Al2O3 in PEO@PVDF polymer electrolytes. Consequently, the PEO@PVDF polymer electrolyte with hexamethylene diisocyanate-modified Al2O3 (PPH@Al2O3) exhibited a perfect room temperature ionic conductivity (9.19 × 10−5 S cm−1), excellent electrochemical stability voltage (4.7 V). The LiFePO4//PPH@Al2O3//Li cell delivers an initial capacity of 139.2 mAh g−1 at 0.2 C and with a capacity retention close to 100% after 100 cycles.

Experimental study on the variation of car radiator frontal area using Al2O3/water-ethylene glycol nano coolant

In automobiles, the cooling system is essential in increasing engine performance. Conventional coolants like water and ethylene glycol have low thermal conductivity. Nanotechnology allows the development of a high thermal conductivity coolant named ‘nanocoolant’, a colloidal suspension. This study is focused on the effect of nanocoolant size on the radiator, which is also responsible for fuel consumption. To prepare nanocoolant two-step method was used, in which nanoparticles were prepared separately and dispersed in a base fluid under ultrasonic agitation. This research was carried out for the dispersion of Al2O3 in a water-ethylene glycol mixture with volume concentrations of 0%, 0.2%, 0.4% and 0.6%. The experimentation was carried out on 180, 216, 288 and 360 mm tube-length radiators. The experiments were conducted at a coolant inlet temperature 65 °C, air velocity of 1.05 m/s, and volume rate of 4 to 9 litres per minute. The result shows that using 0.2% Al2O3 nanoparticles, the overall heat transfer coefficient was augmented by 43% more than the base fluid. It is also seen that for 0.6% volume fraction nanocoolant, approximately 65% reduction in frontal radiator area is possible, which leads to decrement in the drag force and pumping power.