Aerospace Applications Research Articles

Experimental and numerical validation of high strain rate impact response and progressive damage of 3D orthogonal woven composites

Advanced three-dimensional (3D) woven composites for aerospace and automotive applications are commonly subjected to complex dynamic environments involving vibrations and impacts, resulting in examining their impact properties is extremely important. This paper first experimentally discussed the influences of strain rates, weft yarn densities and loading directions on the impact performances and failure mechanisms of 3D orthogonal woven composites (3DOWCs). Secondly, full-scale finite element models were developed to predict the stress distribution and interfacial damage evolution process. The predictions were well in agreement with the experimental results. This research revealed that the impact characteristics exhibited strain rate sensitivity. With increasing weft yarn densities, the high strain rate impact behaviors also improved. Particularly, the warp impact strength of 3DOWCs with a weft yarn density of 2 yarn/cm (W5-2) at 812 s−1 was 17.4% and 24.0% higher than that of 3DOWCs with a weft yarn density of 1.5 yarn/cm (W5-1) at 822 s−1. Meanwhile, warp impact strength consistently exceeded to that of the weft impact strength. Additionally, strain rates, weft yarn densities, and loading directions dramatically affected the stress distribution and interfacial damage evolution process of 3DOWCs. Significant warp yarns fracture and matrix cracking were the principal failure patterns in the warp impact, whereas the damage in the weft impact was dominated by localized fracture of weft yarns and interfacial debonding.

Prediction of one-dimensional acoustic field with axial temperature gradient using neural networks

The study of sound propagation inside the ducts finds extensive application in aerospace, automobiles, speech, and biomedical sectors. This paper presents a neural network-based formulation to estimate the acoustic field inside a uniform duct with temperature gradient along the axial direction. The governing differential equation is derived from the momentum, energy, and state equations. The acoustic field is approximated with a feedforward neural network, and the problem is converted to an unconstrained optimization problem using the trial solution method. The training process is performed using the L-BFGS optimizer and the sine activation function. The acoustic field inside the duct is predicted up to 2000 Hz for linear and exponential temperature profiles. The predicted results are in good agreement with those obtained from the traditional Range-Kutta solver with a maximum relative error of 0.1%. Furthermore, the classical Helmholtz equation without the temperature gradient is solved using the developed neural network formulation. Using these results, a comparative study is conducted to understand the effect of the temperature gradient on the acoustic field inside the duct.

Effect of Powder Spreading Parameters on Laser Absorption Behavior and Processability of High‐Strength Aluminum Alloy Fabricated by Laser Powder Bed Fusion

Laser powder bed fusion (LPBF) of rare‐earth‐modified high‐strength aluminum alloys presents a novel approach for manufacturing complex components with enhanced structural performance, particularly in aerospace applications. This study fabricates Al–Mg–Sc–Zr specimens using various powder spreading parameters to explore their impact on laser processability. The investigation reveals that varying the powder layer thickness from 30 to 70 μm yields the smallest irradiation diameter of 135 μm at an optimal thickness of 50 μm, attributable to effective multiple reflections, high laser absorption rates, and stability. With an optimal laser power of 400 W, a scanning speed of 600 mm s−1, and a hatching spacing of 60 μm, the sample produced at 50 μm layer thickness achieves a relative density of 99.23%, a top surface roughness of 15.42 μm, and a refined grain size of 1.67 μm. Following aging at 325 °C for 4 h, this sample exhibits a tensile strength of 518 MPa and an elongation of 15.6%. The findings establish a theoretical basis for controlling the morphology and properties of high‐strength aluminum alloys in laser additive manufacturing.

Electromagnetic interference shielding, mechanical, and flame retardant behaviors of Ti3C2Tx-MXene/glass fabric epoxy hybrid composites

This study investigates the manufacturability and electromagnetic shielding effectiveness (EMI-SE) of Ti3C2Tx/MXene-coated glass fabric laminated composites for aerospace applications. MXene-coated fabrics were produced using a dip-coating method. The effects of varying dipping counts (5 and 10) and different configurations of fabric arrangements on the EMI-SE of the composites in the X-band range (8.2–12.4 GHz) were investigated. Glass fabrics with 5 and 10 dips showed average surface resistances of 38.56 Ω/sq and 23.17 Ω/sq, respectively. In both the 5- and 10-dip composite sets, the total EMI-SE increased with the number of MXene-coated glass fabric layers in the composite. The 5MXC5 and 10MXC5 specimens, with conductive fabric in all layers, had average total shielding effectiveness (SET) of −18.75 dB and −23.21 dB, respectively. These values are 147.05 % and 205.80 % higher than the neat glass fiber-epoxy composite (C1). Flammability, bending, ILSS, and hardness tests were conducted on these composites. Increasing the MXene content reduced the burning rate, with 10MXC5 exhibiting a 26.31 % lower burning rate compared to C1. However, higher MXene content slightly decreased bending and ILSS values. Optical microscope examination of the fracture surfaces revealed that this decrease was due to delamination damage.

Dual Cross-Linked Networks Reinforced Polyimide Foams with Outstanding Piezoelectric Properties and Heat Resistance Performance.

The application of traditional isocyanate-based polyimide (PI) foams is highly hindered due to limited flame retardancy, poor mechanical properties, and relatively single functionality. Herein, we propose an effective method to fabricate dual cross-linked polyimide/bismaleimide (PI-BMI) foams with outstanding heat resistance and enhanced mechanical properties by incorporating bis(3-ethyl-5-methyl-4-maleimidophenyl)methane (ME-BMI) as the interpenetrating network. The results show that the prepared PI-BMI composite foams exhibit enhanced mechanical properties with lightweight characteristics (23-80 kg·m-3). When the ME-BMI loading reached 120 wt %, the tensile and compressive strength of PI-BMI composite foam can reach 1.9 and 7.8 MPa, which are 9.6 and 63.3 times higher than that of pure PI foam, respectively. In comparison with PIF-0, the 10% heat loss temperature (Td,10%) of PIF-90 improved by 156 °C. Moreover, the PI-BMI foam piezoelectric sensor containing fluorine groups presents a short response time (14.22 ms), high sensitivity (0.266 V/N), and outstanding stability (10 000 cycles). Besides, the sensor can accurately monitor human activity in different states. This work provides a promising strategy for designing multifunctional PI foams, making them suitable for applications in aerospace and microelectronics.

Deformation behavior of aluminum alloy rivets for aerospace applications

For many decades, solid rivets made of high-strength aluminum alloys have been used for mechanical joining of aircraft structures. For numerical modeling of riveting processes the detailed description of the deformation behavior of the rivets is of utmost importance; however, only very little reliable material data are available. Therefore, this study reviews and investigates the deformation behavior of commercial MS20426AD3-5 countersunk rivets made of aluminum alloy AA-2117-T4 as typically used in aerospace applications. The self-consistent procedure for determining the material-specific flow curve includes (i) the exact preparation of cylindrical samples, (ii) compression testing of the samples at testing speeds of 0.05 mm/s, 0.5 mm/s and 5 mm/s, and (iii) inverse numerical modeling of the testing procedure. In general, the compliance of the testing setup must be considered for obtaining reliable flow curves, especially when testing small samples. The determined flow curve of aluminum alloy AA-2117-T4 showed higher yield stress and more distinct initial strain hardening than most of the flow curves published in literature. Although the flow curve did not show any significant strain rate dependency, notable softening due to deformation-induced adiabatic heating of the compressed sample was observed at the highest testing speed. However, the fracture strain seems to be strain rate-dependent, because samples deformed at the low testing speed did not show any signs of macroscopic fracture, whereas local fracture occurred in samples deformed at the medium and high testing speeds.

Performance of advanced ceramic round tools when turning Inconel 718

Nickel-based superalloys, like Inconel 718, are very attractive metals for aerospace applications due to their excellent mechanical properties and thermal stability. However, these materials pose a significant challenge to the metal machining industry due to their very low machinability, especially in terms of reduced tool life because of the high heat generated during cutting. Nevertheless, it can be improved using high-performing tools that retain their hardness when exposed to high temperatures, such as ceramic tools. In this context, the study aims to compare the performance of two advanced ceramic tools, namely an alumina ceramic tool reinforced with SiC whiskers and a Bidemics™ one, when turning Inconel 718 at different cutting speeds, using as a baseline a conventional coated cemented carbide tool. First, the three inserts were characterized in terms of topography, thermal conductivity, and hot hardness to fully understand their operational behavior. Then, turning trials were conducted showing that both the ceramic tools outperform the coated carbide one in terms of tool life, with Bidemics™ demonstrating the best performance among all. This can be ascribed to its very high hardness maintained even at high temperatures, as well as its moderate thermal conductivity.

Study of Helium Irradiation Effect on Al6061 Alloy Fabricated by Additive Friction Stir Deposition

Additive friction stir deposition (AFS-D) is considered a productive method of additive manufacturing (AM) due to its ability to produce dense mechanical parts at a faster deposition rate compared to other AM methods. Al6061 alloy finds extensive application in aerospace and nuclear engineering; nevertheless, exposure to radiation or high-energy particles over time tends to deteriorate their mechanical performance. However, the effect of radiation on the components manufactured using the AFS-D method is still unexamined. In this work, samples from the as-fabricated Al6061 alloy, by AFS-D, and the Al6061 feedstock rod were irradiated with He+ ions to 10 dpa at ambient temperature. The microstructural and mechanical changes induced by irradiation of He+ were examined using a scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and nanoindentation. This study demonstrates that, at 10 dpa of irradiation damage, the feedstock Al6061 produced a bigger size of He bubbles than the AFS-D Al6061. Nanoindentation analysis revealed that both the feedstock Al6061 and AFS-D Al6061 samples have experienced radiation-induced hardening. These studies provide a valuable understanding of the microstructural and mechanical performance of AFS-D materials in radiation environments, offering essential data for the selection of materials and processing methods for potential application in aerospace and nuclear engineering.

Structural, Mechanical and Thermal Behaviour of MWCNT-PCS Hybrid Polymer Matrix Nanocomposites: An Extension Study of Graphene-Epoxy Polymer Matrix Nanocomposites

This study extends previous research on graphene-epoxy nanocomposites by investigating the thermal, mechanical, electrical, and chemical properties of multi-walled carbon nanotube (MWCNT)-reinforced polycarbosilane (PCS) hybrid polymer matrix nanocomposites. Building on the foundational work that demonstrated the enhanced performance of graphene-epoxy nanocomposites, this research explores the potential of MWCNTs as a superior reinforcing agent within the PCS matrix. The MWCNT-PCS nanocomposites were synthesized and characterized using a comprehensive suite of techniques, including X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, specific gravity analysis and surface resistance measurements. The results indicate that MWCNT-PCS nanocomposites exhibit improved thermal stability, higher degradation temperatures, and enhanced thermal conductivity, along with significant improvements in mechanical strength and lower surface resistance, indicating superior electrical conductivity. Additionally, the chemical interactions between MWCNTs and the PCS matrix were analyzed to assess the dispersion and bonding quality, contributing to the overall performance of the nanocomposites. These findings suggest that MWCNT-PCS nanocomposites are promising candidates for high-performance applications in aerospace, where thermal stability, mechanical strength, electrical conductivity and chemical stability are critical. This paper not only confirms the benefits of MWCNT reinforcement but also provides a direct comparison with graphene-epoxy nanocomposites, underscoring the advancements made in this ongoing research.

Orientation engineering of magnesium alloy: A review

Mg and its alloys have garnered significant attention due to their exceptional properties, including low density, good damping capacity, biocompatibility, recyclability, and high hydrogen storage capacity. These attributes position them as promising materials for applications in aerospace, transportation, electronics, and biomedical. The wrought Mg alloys, particularly in sheet form, are important materials for manufacturing lightweight structural components. However, their application is often constrained by relatively low room temperature formability. Preferred orientation, also known as texture, plays a crucial role in determining the plasticity and formability of Mg alloys. In this paper, we propose the concept of “orientation engineering”, which involves controlling the crystallographic orientation, thereby enhancing the plasticity and formability of Mg alloys. This review addresses two main aspects: firstly, it systematically explores how preferred orientation influences the plasticity and formability of Mg alloys, providing a foundation for orientation engineering. Secondly, it comprehensively introduces the development of methods to control grain orientation distribution, including alloying, pre-deformation, and asymmetric processing. This review might enhance the scientific understanding of orientation modification in Mg alloys and offer valuable guidance for future research on high-formability Mg alloys.

Enhanced energy absorption and mechanical properties of porous Ti-6Al-4V alloys with gradient disordered cells fabricated by laser powder bed fusion

Additive manufacturing (AM) has revolutionized the production of porous metals, greatly improving control over their structural properties and offering unprecedented advantages in lightweight applications and energy absorption. Balancing energy absorption and compressive strength in ordered and disordered porous structures is challenging due to shear deformation and deformation mechanisms. This study investigates the mechanical and energy absorption properties of porous Ti-6Al-4V alloys with gradient disordered cells fabricated using laser powder bed fusion (LPBF). The compressive response of samples with different regularities (R) and varying layers of disordered cells was analyzed through quasi-static compression experiments and finite element simulations. The results indicate that introducing a disordered cell gradient significantly enhances energy absorption by preventing the formation of shear bands observed in porous structures with ordered cell structures. When the regularity (R) is 0.8, 0.4, and 0.2 with one or two layers of disordered cells, mechanical properties are optimized and characterized by a balance between compressive strength and energy absorption. It is significant that, while preserving or enhancing compressive strength, the energy absorption of the material can be augmented substantially. Specifically, porous Ti-6Al-4V (R = 0.8, L4) achieves an energy absorption increase of up to 154.9kJ/m³, which represents a dramatic enhancement of approximately 245.0% over the regular porous structure (R = 0 or L0), which absorbs only 44.9 kJ/m³. Compared to ordered and disordered porous structures, the disordered cell gradient demonstrates significant potential in tuning the mechanical properties of porous metals, thereby advancing their applications in aerospace, biomedical, and protective fields.

Preparation and Characterization of Lightweight Carbon Foam Derived From Silicon‐Containing Arylacetylene Resin With Antioxidant Properties and Excellent Electromagnetic Interference Shielding Performance

ABSTRACTIn this study, carbon foam derived from silicon‐containing arylacetylene resin (CFPSA) was prepared by using silicon‐containing arylacetylene (PSA) resin as the carbon precursor and polyurethane (PU) foam as the organic sacrificial template. CFPSAs with diverse apparent densities were prepared through the simple impregnation of PU foam with PSA resin solutions of varying concentrations. Their structures, such as the pore morphology; chemical composition; thermal stability; compression properties, and electromagnetic interference (EMI) shielding effectiveness (SE), were characterized. The results indicate that with an increase in the PSA resin concentration, the skeleton of CFPSA becomes thicker, the pore size slightly increases, the apparent density increases, the compressive strength increases, and the EMI SE slightly reduces. CFPSA‐10's apparent density is 0.032 g/cm3, its 5% thermal weight loss temperature (Td5) in an air atmosphere is 642°C, its thermal conductivity is 38.1 mW/m K, its specific compression strength is 2.45 MPa/g cm3, and its specific EMI SE divided by thickness (SSE/t) is 2367 dB cm2/g. CFPSA exhibits lightweight and antioxidant properties, as well as excellent electromagnetic interference shielding performance, presenting great potential for application in aerospace and other fields.

Part-Scale Microstructure Prediction for Laser Powder Bed Fusion Ti-6Al-4V Using a Hybrid Mechanistic and Machine Learning Model

Laser powder bed fusion (LPBF) Ti-6Al-4V is widely studied for use in structural applications in aerospace and medical industries, but mechanical anisotropy and microstructural inhomogeneity prohibits its wider adoption. Although successful microstructure prediction models have been developed, a remaining challenge is their limited integration across length/time scales and validation by experimental studies. This work proposes a physics-augmented machine learning surrogate model to unite predictions of LPBF temperature, β phase morphology and texture, and α/α’ formation into a single framework that is calibrated and validated with experiments. First, a phase field (PF) model of the martensitic β→α’ transformation is developed and calibrated using data from in-situ synchrotron cyclic heating/cooling studies quantifying the variation of α phase fraction with time. In parallel, an established finite difference-Monte Carlo (FDMC) model predicts the part-scale temperature profile and β grain formation during solidification. A dataset is developed using LPBF cyclic temperature descriptors from the FDMC model as inputs and corresponding α/α’ phase fraction and width from the PF model as outputs. Five machine learning (ML) regression models are tested and optimized, having mean absolute error in testing ≤ 4%, and the k-nearest neighbors (KNN) model is selected as the best performing. The KNN model is called at the nodal level during post-processing of the FDMC model to replace and downscale the response of the PF model. The combined agility and accuracy of the hybrid FDMC-ML model enables part-scale microstructure predictions that can be further used for property predictions to accelerate AM process optimization.

Facilely prepared extreme environments tolerable PIF /c-CNTx composites for piezoresistive sensor based on powder foaming strategy

Polyimide foams (PIF) are widely used in piezoresistive sensors due to their light weight and weather resistance to weathering at extreme temperatures. Nevertheless, the mechanical strength of PIF prepared by freeze-drying method is poor, with only tens to hundreds of kPa ranging from 50 % to 80 % compression. Herein, a polyimide composite reinforced with –COOH functionalized multi-walled carbon nanotubes (PIF/c-CNTx) was produced via a thermal foaming process using a powder-based method. The PIF/c-CNTx composites exhibit ultra-low density (0.165 g/cm3), excellent mechanical properties (compressive strength of up to 2.5 MPa at 60 % compressive strain, tens to hundreds of times higher than similar materials) as well as stable compressive properties and recoverability in liquid nitrogen and at high temperatures up to 200 ℃. The PIF/c-CNTx piezoresistive sensor achieves excellent sensing capability over a wide strain range high sensitivity (GF = 12.9) and exhibit good stability over 5000 s of cyclic compression at a compression rate of 10 mm/min. The stability and reproducibility of the strong piezoresistive signal at extreme temperatures shows the great potential of PIF/c-CNTx composites as structural components under extreme conditions for applications in aerospace and polar exploration.

Ballistic performance of alumina/carbon fiber/aramid composite against impact of different projectile shapes

This study explores the ballistic performance of an alumina/carbon fibre/KevlarⓇ aramid composite panel against impacts from various projectile shapes, including ogive, conical, cylindrical, hemispherical, and 5.56 mm × 45 mm NATO rounds. The aim is to analyse the influence of projectile nose shape on penetration resistance and energy absorption, critical for defence and aerospace applications. Numerical simulations carried out in LS-DYNAⓇ, validated by experimental data, reveal that the ceramic layer effectively initiates projectile deceleration, while the fabric layers absorb the majority of the kinetic energy. Hemispherical projectiles exhibit minimal plastic deformation, highlighting the composite's optimal performance against this shape. In contrast, ogive projectiles demonstrate greater penetrative potential, challenging the composite's multi-layered defence. The study finds that approximately 90% of the kinetic energy is absorbed by the fabric backing, with a small portion absorbed through projectile deformation and ceramic cracking. These results underscore the importance of considering projectile deformation in simulations and suggest that the composite design is well-suited for enhancing protection against high-velocity impacts in defence and aerospace sectors.

Effect of laser beam incident angle on welding of Ti6Al4V with fiber lasers

Laser beam welding (LBW) is widely used for welding Ti6Al4V alloys in aerospace applications. LBW has localized high-energy fluence with low-energy input compared to other fusion welding processes, resulting in narrower heat-affected zones. On the other hand, most metals are highly reflective when the laser beam impinges perpendicular to the surface, making the process inefficient. Hence, this work proposes to employ shallow angle incidence to reduce the reflectivity during the welding of Ti6Al4V material. To explore the potential of this idea, the current study focuses on studying the effect of laser incident angle (15°-90°), power (300 W-1500 W), and feed rate (10 mm/s-25 mm/s) on autogenous weld bead geometry. For this purpose, bead-on plate (BOP) LBW is conducted on mill-annealed Ti6Al4V material of dimensions 25 mm × 25 mm × 3 mm by employing a fiber laser source with a maximum power of 3 kW and a wavelength of 1080 nm. It is observed from the results that at a normal incident angle and low laser power (< 600 W), the penetration depth is too low to generate a weld bead. Analyzing the cross-section of the weld bead, obtained from SEM, perpendicular to the weld direction reveals that the increase in laser incident angle up to an optimal angle resulted in increased bead dimensions (width and height), and beyond that, the dimensions decreased. However, the optimal incident angle changed when the laser power was changed. The major finding of this study is that at 600 W and a normal incident angle, the laser could not penetrate and generate a weld bead due to low absorptivity, while at an incident angle of 300, 450, and 600, weld beads are generated because of increased absorptivity. Similarly, the increase in weld dimensions with the increase in laser power is observed. At higher laser power, underfill and oxide formation are observed. The feed rate is less predominant than the incident angle and the power.

A Non-Melting Additive Approach to Structural Repair of Aluminum Aircraft Fastener Holes

The damage to fastener holes in aerospace aluminum structures presents significant challenges for aircraft durability, and conventional bushing methods for repairing oversized holes often fall short due to the lack of metallurgical bonding and limited edge distance availability. This study investigates additive friction stir deposition, a non-melting additive process, as a viable alternative for the structural repair of aerospace fastener holes. The repair process, demonstrated on AA7050 (Al-Zn-Mg-Cu-Zr) hole structures, involves filling oversized holes with new material and machining to restore the original hole size. The repaired hole coupons are defect-free and exhibit good fatigue performance under fully reversed tension-compression loading (R = -1). At a nominal stress amplitude of 180 MPa, the average number of cycles to failure is 12,666 for unrepaired baseline coupons and 17,372 for effectively repaired coupons. Restoring complex geometries without compromising fatigue performance has been difficult in aerospace applications; this study marks the first demonstration of additive repair that consistently outperforms the unrepaired baseline coupons. Notably, the result is achieved through a low-energy, cost-effective solution without the need for post-repair heat treatment. Except for a few outliers, the post-repair fatigue performance generally remains inferior to that of undamaged, pristine coupons, likely due to precipitate evolution in AA7050 caused by the thermomechanical processing nature of additive friction stir deposition. This evolution weakens the repair region and the adjacent base material, leading to faster crack initiation and growth compared to the properly aged base material, AA7050-T7451.

Valorization of Ricinus communis outer shell biomass to biochar: Impact of thermal decomposition temperature on physicochemical properties and EMI shielding performance

The rising awareness of electromagnetic pollution has increased interest in renewable and ecologically sustainable materials for shielding electromagnetic waves. Research on carbon-based electromagnetic wave absorption materials derived from agro waste is widely explored due to their advantageous characteristics, including low density and consistent physicochemical properties. The research aims to produce biochar with maximum carbon content from Ricinus communis outer shell (RCOS) and to examine the characteristics of biochar/epoxy composites for their application in electromagnetic (EM) shielding. In this study, the composite made from RCOS-based biochar was effectively developed using slow pyrolysis at 400 °C–700 °C. The characterisations of enhanced properties of biochar were conducted by using yield analysis and proximate analysis, elemental analysis, field emission scanning electron microscope (FE-SEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction analysis (XRD), thermogravimetric analysis (TGA), electrical conductivity. The biochar pyrolysis results revealed that the biochar yield, fixed carbon and maximum carbon content were 30 wt%, 50.49 wt% and 79.2 wt%, respectively, at 700 °C. Fourier transform infrared (FTIR) spectroscopy revealed that for the biochar at 700 °C, C=C and C-H functional groups were present, and the others were eliminated as volatile gases during biochar production. TG analysis demonstrated higher biochar stability with residues of 75 % for 700 °C. The biochar produced at 700 °C possesses the maximum electrical conductivity of 95 S/m due to the presence of graphitic carbon. The vector network analyser (VNA) measured a maximum shielding efficiency of 26.5 dB in the X-band frequency when adding 40 wt% biochar prepared at 700 °C to the epoxy matrix. The results suggest that the RCOS biochar/epoxy composites have promise as a novel type of absorbent materials because of their low density, lightweight structure, and extensive absorption capacities. These biochar-based lightweight composites can be used as a shielding material for electronic enclosures, telecommunication equipment, and aerospace applications.

Enhanced wear resistance, corrosion behavior, and thermal management in magnesium alloys with PEO coatings

The harsh conditions encountered in aerospace applications, such as high operational temperatures, abrasive wear, and corrosive substances, present significant challenges to the performance and longevity of magnesium alloy components. To create a coating with superior wear resistance, corrosion resistance, and high emissivity, this study employs plasma electrolytic oxidation (PEO) technology to develop a nanocomposite coating doped with carbon nanotubes (CNTs) and hexagonal boron nitride (h-BN). The results demonstrate that the MgO-BN/CNTs coating with an emissivity of 0.82 reduces the equilibrium temperature of the 5 W LED junction by nearly 10 °C compared to the magnesium alloy substrate, showing improved radiative heat dissipation performance. Due to the ability of the porous structure to accommodate abrasive particles, coupled with the lubricating effect of h-BN and CNTs, the friction coefficient of the MgO-BN/CNTs coating is 0.57, which is 21 % lower than that of the MgO coating. Additionally, the coating exhibits excellent corrosion protection, attributed to the dense microstructure and chemical inertness of h-BN. The findings demonstrate that the strategic incorporation of h-BN and CNTs into PEO coatings effectively improves the wear resistance, corrosion resistance, and thermal management performance of magnesium alloys.

Fatigue limit prediction of 7050 aluminium alloy based on experimental and shallow + deep hybrid neural network

7050 aluminium alloy, as an important lightweight high-strength structural material because of its excellent characteristics, has increasing applications in aviation, aerospace, and launch vehicle manufacturing. Fatigue failure accounts for approximately 80 % of the structural failures in the engineering field, which leads to numerous losses and is highly uncertain and sudden. Therefore, fatigue life prediction of 7050 aluminium alloy has become a prominent research field. In this study, considering the two variables of stress ratio and stress concentration coefficient, fatigue tests of 7050 aluminium alloy under five different working conditions were conducted to evaluate the effect of these factors on the durability of 7050 aluminium alloy. A novel hybrid neural network model was proposed to solve the time-consuming problem of obtaining a large amount of S-N curve data through traditional fatigue tests. The model uses relatively low cycle fatigue test data for training, realizes data derivation, accurately predicts the fatigue limit of materials, and realizes the purpose of quickly evaluating the fatigue properties of 7050 aluminium alloy materials under different working conditions.