Al Components Research Articles

Insights into Structural Changes During Scratch Deformation of Ductile Coating Systems: Plastic Flow, Microstructural Transformations, and Crack Development

This study investigates the structural changes occurring during the scratch deformation of ductile materials, focusing on a composite aluminum (Al) coating on a steel substrate fabricated using a solid-state aluminizing technique. By analyzing the results of the scratch test with transmission electron microscopy (TEM) and focused ion beam (FIB) techniques, the research provides a detailed examination of plastic flow, microstructural transformations, and crack development. Results demonstrate that strong adhesion at the interface and similar mechanical properties between steel and Al layers facilitate co-deformation, crucial for maintaining the integrity of the composite structure. The study features the formation of a rolling-like laminated structure and significant grain refinement in both the steel and Al components, driven by plastic deformation. Observed atomic-scale intermixing and the formation of an amorphous interlayer highlight extensive material interactions during deformation. The visualization of crack progression using FIB allows for an in-depth understanding of the fracture process. Subsurface cracks initiate within the thin Al interlayer and propagate toward the surface, evolving through the coalescence of nanopores into microvoids and larger cavities, ultimately leading to crack propagation. Secondary internal cracks may arise due to stress fields generated by the primary crack, contributing to a complex network of internal cracks.

Utilization of corn cob ash (CCA) to prepare geopolymer grout: Reaction mechanism, crack repair effectiveness and life cycle assessment

Corn cob ash (CCA) is a kind of agricultural solid waste produced by the burning of corn cob after removal of the corn kernels, which requires sustainable disposal routes. In order to utilize CCA and understand its role in geopolymer, CCA-amended geopolymer grout was prepared and effects of CCA on geopolymerization process and products were investigated in this study. With CCA included, there was less C-S-H/C-A-S-H gel and more calcite, also portlandite generated. Two extra weak exothermic peaks were observed for CCA-amended geopolymer with optimal mix proportion (CCA20A6), probably due to additional reactions induced by CCA, also verified by the disappearance of syngenite. Following application of CCA20A6 to repair cracks, compressive strength and ultrasonic pulse velocity (UPV) of the repaired composites were improved, and no cracking was observed at the bonding interface, verifying successful repair. Based on life cycle assessment in cradle-to-site boundary, the total embodied energy (EE) and global warming potential (GWP) of CCA20A6 were decreased by 7.8% and 15.5%, respectively, compared to non-CCA geopolymer. Considering performance of samples, the addition of CCA would lead to an about 30% decrease in economic index. In conclusion, CCA could play a role as a precursor due to soluble Si, Al, and Ca components, and also as an activator due to its intrinsic alkalinity, which makes CCA-amended geopolymer to be an eco-friendly grouting material with better performance as well as lower costs.

Synergistic Leaching of Titanium, Aluminum, and Magnesium Components during Dilute Acid Pressure Treatment of High-Titanium Blast Furnace Slag.

This study focuses on an improved leaching process through the combination of pressurized conditions and direct filtration of acid leaching slurry, which is conductive to improving the filterability of acid leaching systems and the extraction rates of Ti, Al, and Mg components. The effects of sulfuric acid concentration, reaction temperature, particle size of materials, acid-slag ratio, and reaction time on the leaching efficiency were systematically investigated. The results showed that pressurization significantly enhances the filtration efficiency of the reaction slurry. Under the same filtration time, the filtration efficiency increased from 46% under ordinary pressure to 78% under pressurized conditions. Moreover, under the optimal reaction conditions, the extraction rates of Ti, Al, and Mg components were more than 88.21%, 97.8%, and 96.31%, respectively. Additionally, XRD and FTIR showed that titanium oxide sulfate hydrate crystals were produced in the acid-leached residues when the reaction temperature exceeded 190 °C, thereby reducing the extraction rate of Ti component. And the XRD pattern shows that when the reaction temperature is maintained at 190 °C and the reaction time is extended to 150 min, titanium oxide sulfate hydrate crystals will be formed to reduce the extraction rate of the Ti component. In summary, this study not only provides important theoretical support for the resource utilization of high-titanium blast furnace slag but also offers a feasible solution for efficient extraction and convenient filtration, thus holding significant academic and practical implications.

Investigation of Carbonation Kinetics in Carbonated Cementitious Materials by Reactive Molecular Dynamics Simulations.

Calcium carbonate (CaCO3) precipitation plays a significant role during the carbon capture process; however, the mechanism is still only partially understood. Understanding the atomic-level carbonation mechanism of cementitious materials can promote the mineralization capture, immobilization, and utilization of carbon dioxide, as well as the improvement of carbonated cementitious materials' performance. Therefore, based on molecular dynamics simulations, this paper investigates the effect of Si/Al concentrations in cementitious materials on carbonation kinetics. We first verify the force field used in this paper. Then, we analyze the network connectivity evolution, the number and size of the carbonate cluster during gelation, the polymerization rate, and the activation energy. Finally, in order to reveal the reasons that caused the evolution of polymerization rate and activation energy, we analyze the local stress and charge of atoms. Results show that the Ca-Oc bond number and carbonate cluster size increase with the decrease of the Si/Al concentration and the increase of temperature, leading to the higher amorphous calcium carbonate gel polymerization degree. The local stress of each atom in the system is the driving force of the gelation transition. The presence of Si and Al components increases the atom's local stress and average charge, thus causing the increase of the energy barrier of CaCO3 polymerization and the activation energy of carbonation.

Analysis and simulation of bulk polarization mechanism in p-GaN HEMT with AI component gradient buffer layer

In this paper,bulk polarization mechanism and radiation simulation of the Al component gradient buffer layer (GBL) and constant buffer layer (CBL) of p-GaN HEMT (p-GaN GBL-HEMT and p-GaN CBL-HEMT) are analyzed and studied. It is found that the p-GaN GBL-HEMT can significantly reduce the buffer leakage current. The linear gradient amplitude (the range of linear gradients of Al components vertically in the buffer) of 20%–25% Al components can significantly increase the breakdown voltage (V BK) of the device, up to 1312 V. Simultaneously, although the p-GaN GBL-HEMT reduces the 2DEG concentration, the device still has a specific on-resistance (R ON,sp) and drain saturation current (I DS,sat) equivalent to the p-GaN CBL-HEMT due to the conductivity modulation effect. Its Baliga figure of merit is up to 2.27 GW cm−2. Finally, through the SEE simulation and the bulk polarization mechanism analysis, it is found that the drain transient current (I DS,trans) by the identical incident particles in the p-GaN GBL-HEMT is lower than that in the p-GaN CBL-HEMT, and the I DS,trans decreases with the increase of the Al components gradient amplitude. Therefore, the p-GaN GBL-HEMT provides a new idea for improving the electrical performance and SEE hardening.

Structural and electronic properties of AlGaN nanowires modulated by Al component and sectional size: A first principles study with DFT+U method

AlGaN nanowires have plenty of applications in optoelectronic functional devices. However, the electronic characteristics and stability of AlGaN nanowires are rarely explored, especially for an actual prediction of bandgaps with varying Al components. In this work, we utilize first principles calculation with DFT + U method to study the stability, charge redistribution, band structures, density of states of AlxGa1-xN alloy nanowires with x spanning from 0 to 1. The results indicate that the stability of the nanowire is enhanced with increasing nanowire diameter and Al component. The bond length in the outermost layer, vertical to the specified direction, is stretched as the Al component increases. The bandgap of nanowire is larger than that of bulk phase and the bowing parameter of nanowire is relatively low. According to the analysis of density of states (DOS), the migration of band structures is attributed to N-p states at VBM and Ga-s and Al-p states at CBM. The calculation of Crystal Orbital Hamilton Population (COHP) reveals the variation of bandgap with changing Al component and diameter. According to the analysis of electron density difference and charge transfer, Al atom has a stronger electron negativity and the electron density surrounding Ga is more delocalized compared Al atom. The results obtained in this study is expected to give some guidance for the preparation of optoelectronic devices based on AlGaN nanowires.

Qualea grandiflora Mart. (Vochysiaceae) seed reserves and aluminum: Usage and mobilization during germination and seedling development

AbstractQualea grandiflora Mart. is an aluminum (Al)‐accumulating Cerrado species with a metabolic dependency on Al. This study aimed to determine the presence and concentration of Al and other reserve components in Q. grandiflora seeds, as well as their respective distribution patterns, mobilization, and usage during germination and seedling growth. Thus, the concentration of Al and other minerals in seeds, seedlings, and soils was measured. Also, histochemical and energy‐dispersive X‐ray spectroscopy (EDS) analyses were performed to observe the distribution of Al, proteins, and lipids in Q. grandiflora seeds and seedlings. Additionally, the concentration of proteins and lipids was assessed as well. Hence, even in soils with low exchangeable Al3+, Q. grandiflora seeds accumulated about 6.43 g of Al/kg of dry matter (DM) together with considerable concentrations of N, P, K, Ca, and Mg. Exogenous Al had no effect on the germination properties of Q. grandiflora seeds. Furthermore, approximately 60% of the seed Al was translocated to seedling leaves. Proteins and lipids were the main organic reserves in Q. grandiflora seeds. The histochemical analysis revealed that the bulk of Al in seeds was in the cotyledons, which were also the location sites of proteins and lipids. Proteins and lipids were the primary source of energy and carbon for seedling growth. Therefore, fatty acids, proteins, and Al could play a central role during seed germination and seedling establishment, which could help to explain why this species is one of the most widespread plants in the Cerrado.

Possibility of Phase Transformation of Al2O3 by a Laser: A Review

Aluminum (Al) components of high quality often require an optimal ratio of lightness and favorable mechanical properties. In order to improve the physical-mechanical properties of Al, an aluminum oxide (Al2O3) film is usually formed on the surface of Al, which itself is characterized by high strength, hardness, corrosion resistance, and other technical properties. Unfortunately, depending on the conditions, the oxide film may be formed from different crystal phases on the Al surface, which are not always of desirable quality, i.e., the α-Al2O3 phase. The present review demonstrates that the properties of the Al2O3 film may be improved by Al processing with a laser beam according to the scheme: Al (Al alloy) → electrochemical anodizing → treatment with laser irradiation → α-Al2O3. Both Al substrate and the anodizing electrolyte affect the phase transformation of anodic Al2O3. Laser irradiation of the Al2O3 surface leads to high heating and cooling rates, which may promote the formation of a highly crystalline α-Al2O3 phase on anodic Al2O3.

Damage Effects and Mechanisms of High-Power Microwaves on Double Heterojunction GaN HEMT

In this paper, simulation modeling was carried out using Sentaurus Technology Computer-Aided Design. Two types of high electron mobility transistors (HEMT), an AlGaN/GaN/AlGaN double heterojunction and AlGaN/GaN single heterojunction, were designed and compared. The breakdown characteristics and damage mechanisms of the two devices under the injection of high-power microwaves (HPM) were studied. The variation in current density and peak temperature inside the device was analyzed. The effect of Al components at different layers of the device on the breakdown of HEMTs is discussed. The effect and law of the power damage threshold versus pulse width when the device was subjected to HPM signals was verified. It was shown that the GaN HEMT was prone to thermal breakdown below the gate, near the carrier channels. A moderate increase in the Al component can effectively increased the breakdown voltage of the device. Compared with the single heterojunction, the double heterojunction HEMT devices were more sensitive to Al components. The high domain-limiting characteristics effectively inhibited the overflow of channel electrons into the buffer layer, which in turn regulated the current density inside the device and improved the temperature distribution. The leakage current was reduced and the device switching characteristics and breakdown voltage were improved. Moreover, the double heterojunction device had little effect on HPM power damage and high damage resistance. Therefore, a theoretical foundation is proposed in this paper, indicating that double heterojunction devices are more stable compared to single heterojunction devices and are more suitable for applications in aviation equipment operating in high-frequency and high-voltage environments. In addition, double heterojunction GaN devices have higher radiation resistance than SiC devices of the same generation.

Theoretical Studies of 2D Electron Gas Distributions and Scattering Characteristics in Double‐Channel n‐Al0.3Ga0.7N/GaN/i‐AlxGa1−xN/GaN High‐Electron‐Mobility Transistors

A detailed analysis of self‐consistent potentials, electric fields, electron distributions, and transport properties of dual‐channel (DC) n‐Al0.3Ga0.7N/GaN/i‐AlxGa1−xN/GaN high‐electron‐mobility transistors (HEMTs) is performed in this article. The 2D electron gas (2DEG) densities and mobility states limited by different scattering mechanisms in channel 1 and channel 2 are obtained, with varying values of doping concentrations, ambient temperatures, Al components, and thicknesses of the back barrier layer. The reduced and increased 2DEG densities are respectively observed in channel 1 and channel 2 with growing Al fractions and thicknesses of the AlxGa1−xN layer. Alloy disorder scattering exhibits a superior effect on carriers in channel 2 due to the lower barrier height and higher permeable electrons, which together with the interface roughness scattering severely depends on the thicknesses and Al fractions of the back barrier layer. Polar optical phonon scattering becomes important at higher temperatures. The trend of individual mobility in channel 1 is exactly opposite to that in channel 2. The parameter variation of the back barrier layer can effectively change the scattering characteristics of the main channel. Low‐temperature mobilities of n‐Al0.3Ga0.7N/GaN/i‐AlxGa1−xN/GaN HEMTs under varied doping concentrations are also obtained. Finally, the results are verified by comparison with the technology computer‐aided design simulations for DC HEMTs.

Quantitative study on the photoemission of AlGaN nanoarrays based on the three-dimensional transportation within a four-step process.

Photocathodes play a crucial role in photoelectronic imaging and vacuum electronic devices. The quantum efficiency of photocathodes, which determines their performance, can be enhanced through materials engineering. However, the quantum efficiency of conventional planar photocathodes remains consistently low, at around 25%. In this paper, we propose what we believe is a novel structure of AlGaN nanowire array to address this issue. We investigate the photoemission characteristics of the nanowire array using the "four-step" process, which takes into account optical absorption, electron transportation, electron emission, and electron collection. We compare the quantum efficiency of nanowire arrays with different structure sizes and Al components. After studying the effect of incident light at various angles on the nanowire array photocathode, we identify the optimal dimensional parameters: a height of 400∼500 nm and a wire width of 200∼300 nm. Furthermore, we improved the collection efficiency of the photocathode by introducing a built-in/external electric field, and obtained a 104.4% enhancement of the collection current with the built-in electric field, meanwhile the photocurrent was increased by 87% compared to the case without the external electric field. These findings demonstrate the potential of optimizing photocathode performance through the development of a novel model and adjustment of parameters, offering a promising approach for photocathode applications.

Spectral Characterization of Battery Components from Li-Ion Battery Recycling Processes

Considering the increasing demand for Li-ion batteries, there is a need for sophisticated recycling strategies with both high recovery rates and low costs. Applying optical sensors for automating component detection is a very promising approach because of the non-contact, real-time process monitoring and the potential for complete digitization of mechanical sorting processes. In this work, mm-scale particles from shredded end-of-life Li-ion batteries are investigated by five different reflectance sensors, and a range from the visible to long-wave infrared is covered to determine the ideal detection window for major component identification as relevant input signals to sorting technologies. Based on the characterization, a spectral library including Al, Cu, separator foil, inlay foil, and plastic splinters was created, and the visible to near-infrared range (400–1000 nm) was identified as the most suitable spectral range to reliably discriminate between Al, Cu, and other battery components in the recycling material stream of interest. The evaluation of the different sensor types outlines that only imaging sensors meet the requirements of recycling stream monitoring and can deliver sufficient signal quality for subsequent mechanical sorting controls. Requirements for the setup parameters were discussed leading to the setup recommendation of a fast snapshot camera with a sufficiently high spectral resolution and signal-to-noise ratio.

Enhancing reactivity of granite waste powder toward geopolymer preparation by mechanical activation

Granite waste powder (GWP) is a solid waste produced during stone processing, and its accumulation has brought serious environmental and ecological problems. Due to its rich Si and Al components, GWP is a potential raw material for the preparation of geopolymers, but its low reactivity limits its utilization. This study aimed to enhance the reactivity of GWP toward geopolymer preparation by mechanical activation. During mechanical activation, the particle size of GWP decreased rapidly, and its internal pore volume gradually increased, which made its specific surface area continuously increase. The relative crystallinity of the main mineral phases in GWP decreases continuously with mechanical activation, and the aluminosilicate minerals (including albite, microcline, and biotite) are more easily amorphized than quartz. Leaching tests show that activated GWP can dissolve higher percentages of silicon and aluminum components in alkaline solutions. After 120 min of activation, the dissolution percentage of Si increased from 1.55% to 6.25%, and that of Al increased from 4.83% to 20.86%. The reaction heat result shows that the early geopolymerization involving activated GWP releases higher cumulative heat, which reflects a higher degree of reaction. Also, geopolymer incorporated with activated GWP, its compressive strength increased from 50.83 MPa to 78.94 MPa, and its flexural strength increased from 7.2 MPa to 10.0 MPa. These results confirmed that the reactivity of GWP can be significantly enhanced by mechanical activation. This technology may provide an efficient and promising method to improve the reactivity of GWP and promote its utilization in the preparation of geopolymers.

A Deep-Penetrating Geochemical Prospecting Experiment of Mahuagou Gold Deposit in the Core of the Huangling Anticline, Western Hubei, China

The Mahuagou gold deposit is among the most important gold deposits in the core of the Huangling Anticline. However, the geochemical exploration on the surface of the mining area presents challenges due to the thin overburden. This paper focuses on the overburden soil of the Fengxiangshugou (FXS)-Mahuanggou (MHG) section as the research object. It utilizes chemical form analysis of gold, soil halogen survey, and heat-released mercury survey to determine the key deep-penetrating geochemical methods for the mining area. The results indicated that Si and Al components of samples exhibit minimal variation, suggesting that drift loads did not influence the overburden soil. Based on the systematic clustering, As, Sb, Mo, Bi, W, and Hg emerge as ore-body or ore-belt front elements of hydrothermal gold deposits. In the study area, the predominant chemical form of gold in soil is the strong organic bond. Compared to the total amount, strong organic bound gold and heat-released mercury show higher anomaly contrasts, making them crucial indicators of faults, intrusions, and hidden ore bodies. Consequently, chemical form analysis of gold and heat-released mercury surveys can enhance the anomaly contrast, proving beneficial for geochemical prospecting for weak anomalies in this area.

Research on vertical GaN devices based on gradient Al components

A groove-gate power device with a linearly gradient Al composition P-type AlGaN superjunction (abbreviated as LG-SJCAVET) is proposed, which uses polarized P-type AlGaN material instead of the traditional P-type GaN buried layer, avoiding the technical bottleneck of achieving high-aspect-ratio P-type doping in GaN materials. Simulation results show that, under the same structural parameters, the breakdown voltage of LG-SJCAVET reaches 2954V, and the on-resistance is 1.669 mΩ⋅cm2, which is due to no current flowing through the P-pillar, resulting in an increase in on-resistance, while affecting the DC characteristics of the device. The power figure of merit of the device is 5.27 GW/cm2, which is 67.11% and 27.38% higher than that of the traditional device and P-type GaN buried layer device, respectively. Therefore, the LG-SJCAVET device solves the problems of the high technical difficulty of the traditional P-type GaN buried layer process, difficulty in activating acceptor impurities, and poor thermal stability of the device, exhibiting superior breakdown voltage characteristics.

Effect of Stacking Sequence on Mechanical Properties and Microstructural Features within Al/Cu Laminates.

The study presents a method to prepare Al/Cu laminated conductors featuring two different stacking sequences using rotary swaging, a method of intensive plastic deformation. The primary focus of the work was to perform detailed characterization of the effects of room temperature swaging on the development of microstructures, including the Al/Cu interfaces, and internal misorientations pointed to the presence of residual stress within the laminates. The results revealed that both the Al and Cu components of the final laminates with 5 mm in diameter featured fine, more or less equiaxed, grains with no dominating preferential texture orientations (the maximum observed texture intensity was 2.3 × random for the Cu components of both the laminates). This fact points to the development of dynamic restoration processes during swaging. The analyses of misorientations within the grains showed that residual stress was locally present primarily in the Cu components. The Al components did not feature a substantial presence of misorientations, which confirms the dynamic recrystallization. Tensile testing revealed that the laminates with both the designed stacking sequences exhibited comparable UTS (ultimate tensile strength) of almost 280 MPa. However, notable differences were observed with regard to the plasticity (~3.5% compared to less than 1%). The laminate consisting of Al sheath and Cu wires exhibited very low plasticity as a result of significant work hardening of Al; this hypothesis was also confirmed with microhardness measurements. Observations of the interfaces confirmed satisfactory bonding of both the metallic components.

The characteristics and microscopic mechanism of Al-Mg alloy powder explosion inhibited by MCA and NaH2PO4

The fine dust can be produced and suspended in the air during Al-Mg alloy polishing process, which has a high risk of powder explosion. To investigate the inhibition effects of ammonium salts and phosphates, the suppressants of melamine cyanurate (MCA) and NaH2PO4 were selected for preventing the explosion of Al-Mg alloy powder. The results showed that the inhibition sensitivity of MCA on Al-Mg alloy powder is superior to NaH2PO4. According to the results of the functional groups on the explosion products, it showed that the effective inhibitory concentrations of MCA for Mg and Al components are 20 wt% and 40 wt%, while the corresponding inhibitory concentrations of NaH2PO4 are 50 wt% and more than 70 wt%, respective. The explosion suppression mechanism of MCA mainly included the effects of gas-phase inerting and chain reaction interruption, whereas the mechanism of NaH2PO4 was oxygen isolating by physical covering and chain reaction interruption. MCA and of NaH2PO4 can suppress the flame propagation by the consumption of the H and OH free radicals. The consumption rate of MCA on O radical was six times that of NaH2PO4. The inhibiting effect of MCA on Al-Mg alloy powder explosion was superior to NaH2PO4. The results provides theoretical basis for the prevention and control of explosion accidents on Al-Mg alloy powder.

Al-Fe Based Molten Salts for Long Duration Energy Storage

There is a need for high energy density long duration energy storage that utilizes earth abundant elements, such as Al and Fe. Energy storage devices that utilize molten salt electrolytes can take advantage of these earth abundant materials and promise to deliver high energy densities. Continued development and in-depth investigation of these fully inorganic, molten salt electrolytes is necessary for the continued progress of low-cost battery technologies. We have been exploring the properties of a new molten salt system which utilizes Al and Fe components and can feasibly be operated as an electrochemically active medium for long duration energy storage. Ternary molten salt compositions of AlCl3-FeCl3-NaCl and AlCl3-FeCl2-NaCl were evaluated for their phase behavior and electrochemical performance at intermediate temperatures (~160 - 210 °C). We found that certain compositions of AlCl3-FeCl3-NaCl were fully or nearly fully molten at 160 °C and that more AlCl3 was needed in the melt to facilitate the FeCl2 dissolution. The electrochemistry of these salts was probed and found that the Fe species will cycle between the Fe3+/Fe2+ oxidation states (as FeCl3/FeCl2) but that at lower temperatures, the FeCl2 will precipitate out of the melt and block the electrode. By increasing the test temperatures, the produced FeCl2 dissolves into the melt allowing the un-blocked electrode to sustain large reduction currents. Future work will investigate ways to increase FeCl2 concentration in the melt and to facilitate its oxidation in order to optimize the molten salt catholyte electrochemical behavior and demonstrate it in a working battery.This work was supported by the U.S. Department of Energy’s Office of Electricity through the Energy Storage Research Program, managed by Dr. Imre Gyuk. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC, a wholly-owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. This paper describes objective technical results and analysis. Any subjective views or opinions that might be expressed in the paper do not necessarily represent the views of the U.S. Department of Energy or the United States Government.SAND2022-16623 A

Characterization of Al-12Si Thin-Wall Properties Fabricated with Laser Direct Energy Deposition

Additive manufacturing is an emerging process that is used to manufacture industrial parts layer by layer and can produce a wide range of geometries for various applications. AM parts are adopted for aerospace, automobiles, antennas, gyroscopes, and waveguides in electronics. However, there are several challenges existing in manufacturing Al components using the AM process, and their mechanical and microstructural properties are not yet fully validated. In the present study, a gas-atomised powder of a eutectic Al-12Si alloy was used as feedstock for the Laser Direct Energy Deposition (LDED) process. A SEM analysis of Al-12Si powder used for processing illustrated that particles possess appropriate morphology for LDED. A numerical control system was used to actuate the deposition head towards printing positions. The deposited samples revealed the presence of Al-rich and Al-Si eutectic regions. The porosity content in the samples was found to be around 2.6%. Surface profile roughness measurements and a microstructural analysis of the samples were also performed to assess the fabricated sample in terms of the roughness, porosity, and distribution of Al and Al/Si eutectic phases. The tensile properties of fabricated thin walls were better compared to casted Al alloys due to the uniform distribution of Si in each layer. Micro-hardness tests on the deposited samples showed a hardness of 95 HV, which is equivalent to casted and powder bed fusion melting samples. The gas atomised Al-12Si powders are highly reflective to a laser and also quick oxidation takes place, which causes defects, porosity, and the balling effect during fabrication. The results can be used as a base guide for the further fabrication of aerospace component design with high structural integrity.

Effect of Al2Cu constituent layer thickness discrepancy on the tensile mechanical behavior of Cu/Al2Cu/Al layered composites: a molecular dynamics simulation

Nano-polycrystalline Cu/Al2Cu/Al layered composites with different layer thicknesses d of single-crystal Al2Cu constituent are constructed. The effects of d on the strength and fracture modes of nano-polycrystalline Cu/Al2Cu/Al layered composites are systematically investigated by molecular dynamics simulations. The uniaxial tensile results show that the ultimate strength and fracture mode of the nano-polycrystalline Cu/Al2Cu/Al layered composites do not change monotonically with the change of single crystal Al2Cu constituent layer thickness d, the ultimate strength peaking at d = 2.44 nm, and the toughness reaching the optimum at d = 4.88 nm. The improvement of deformation incompatibility between Cu, Al and Al2Cu components increases the ultimate strength of polycrystalline Cu/Al2Cu/Al laminated composites. Due to the high activity of Cu dislocation and the uniformity of strain distribution of single crystal Al2Cu, the fracture of nano-crystalline Cu/Al2Cu/Al layered composites changes from brittleness to toughness. This study is crucial to establish the organic connection between microstructure and macroscopic properties of Cu/Al layered composites. To provide theoretical basis and technical support for the application of Cu/Al layered composites in high-end fields, such as automotive and marine, aerospace and defense industries.