The co-sintered phosphor of cerium-doped yttrium aluminum garnet (YAG:Ce) and aluminum nitride (AlN) is a promising material for next-generation light-emitting diode lighting applications. Despite AlN’s excellent thermal conductivity, its high sintering temperature and surface reactivity limit its industrial use in co-sintered phosphors, and effective methods to improve its sinterability without compromising properties remain underexplored. In this study, the sinterability of the AlN and YAG:Ce composite is improved by coating AlN particles with a soluble carbon material (SCM) prior to sintering. SCM coating leads to a 6.75% increase in photoluminescence (PL) intensity under 15 W laser excitation and a 6.85% improvement in thermal conductivity, which suppresses thermal quenching. The enhanced thermal conductivity also minimizes PL decay over time, thereby maintaining high luminosity for extended periods. Furthermore, the hardness and handling properties of the obtained sintered body are significantly improved, with hardness increasing by 112.3% when SCM-coated AlN is used. Notably, the SCM does not remain in the final product, as it is fully removed during sintering, leaving no impurities or adverse effect on the material’s properties. Given its ability to easily and uniformly coat ceramic particles, SCM coating holds promise for broader application in enhancing the sinterability and performance of various ceramic-based materials.

In this study, GNPs/FeCoNiCuAl particles synergistically reinforced aluminum matrix composites are developed by friction stir processing (FSP) to explore the effects of different GNPs contents (1, 3, and 5%) on the microstructure, mechanical performance, and wear resistance of the materials. The results show that the incorporation of GNPs affects the formation of the diffusion layer between the FeCoNiCuAl particles and the aluminum matrix. As the content of GNPs increases, the thickness and integrity of the diffusion layer between FeCoNiCuAl particles and aluminum matrix gradually decrease. In addition, the introduction of GNPs is beneficial in enhancing the proportion of high-angle grain boundaries in the composites, but the grain size of the specimen increases slightly to about 5.5 μm at a content of 5% GNPs. When the content of GNPs is 1%, the composites achieve the highest microhardness and the lowest specific wear rate (0.1459 × 10⁻⁶ mm3/ N·m), with the wear mechanism dominated by abrasive wear. Nonetheless, when the GNPs content in the composite increases to 5%, the thickness and integrity of the diffusion layer are minimal, causing the tensile strength of the composite to be reduced to 250 MPa, and the specific wear rate increased to 0.4244 × 10– 6 ( mm3/N·m), with the wear mechanism transformed to abrasive–adhesive mixed wear. This study demonstrates that the appropriate ratio of GNPs and FeCoNiCuAl particles can effectively enhance the mechanical and wear resistance properties of aluminum matrix composites, providing a theoretical basis for the design and development of high-performance aluminum matrix composites.

This study investigates the thermo-mechanical behavior and residual stress characteristics of friction stir welding (FSW) in an aluminum inverter housing using finite element analysis (FEA). FSW experiments were first conducted under various tool rotation and traverse speed conditions, and temperature histories were measured using K-type thermocouples. The optimal process condition was identified through tensile testing, and the heat input was estimated by comparing experimental and numerical results. The estimated heat source was incorporated into a transient thermal elasto-plastic analysis to evaluate deformation and residual stresses in an inverter housing model. The results indicated that residual stress distributions varied depending on the welding start position. In particular, when welding started at P3 (near thick ribs and bosses) residual stresses were reduced by approximately 30% compared to P1, owing to the higher local stiffness and enhanced heat dissipation that mitigated temperature gradients. Conversely, welding initiated at P1, a flat region with insufficient reinforcement, resulted in higher stress concentrations. These findings confirm that the welding start position significantly influences residual stress behavior in inverter housings and provide fundamental insights for developing residual stress control strategies in FSW of large-scale components.

The Al-Fe-Mg-Cu-B system aluminum alloy is used for electrical wire, but is severely deformed by the multi-pass drawing process when a rod with a diameter of 12 mm is greatly reduced to 2.0 mm. This study investigated the changes in the microstructure, mechanical properties, and electrical properties of the aluminum wire during the drawing process in detail. The as-drawn aluminum alloy wire exhibited a deformation structure in which the grains were greatly elongated in the drawing direction, particularly in the specimens subjected to more than 80 % reduction in cross-sectional area (RA). For all drawn specimens, the fiber texture of the {110}<111> and {112}<111> components was mainly developed. The hardness tended to increase with increasing RA due to work hardening. In particular, when the RA increased to 97 % a great increase in hardness resulted. The specimen with an RA of 97 % showed the highest tensile strength of 288 MPa, 2.2 times higher than that of the specimen before drawing. The electrical conductivity decreased slightly with increasing RA, even in specimens with extreme increases in RA, and it remained at an average value of 56.6 %IACS.

The constituents of coal tar pitch (CTP) significantly impact the wettability of calcined coke (CC) and the performance of prebaked anodes (PA) used in aluminum electrolysis. However, balancing wettability and carbon residue within CTP remains a central challenge in material applications. In addition, limited pore permeability and structural stability in these composites hinder the effective utilization of PA. Enhancing CTP fluidity is crucial for overcoming these challenges. In this work, a novel method was developed to modify CTP utilizing various coal tar fractions, enabling controlled modulation of CTP composition and wettability. Incorporating different fractions allowed for substantial control over interfacial bonding and pore structure. The chemical composition, functional groups, and elemental content of the CTP were analyzed via X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), and proton nuclear magnetic resonance (1H NMR). Subsequently, systematic comparisons of PA materials produced from different CTP formulations demonstrated improved wettability and enhanced mechanical properties. Moreover, DFT calculations were performed to compare the adsorption energies of small molecules from different coal tar fractions with coke, reflecting the interaction strength between the molecules and the solid surface. Using micro-computed tomography (μ-CT), the refined pore structure was examined, resulting in a PA composite with an optimized balance of high strength and toughness.

In aluminum electrolysis, carbon anodes fulfill dual functions: providing electrical conductivity and participating in electrochemical reactions. However, these anodes face challenges such as cracking and degradation, which adversely affect their performance and longevity. Consequently, improving the quality of carbon anode is crucial to enhancing the production efficiency of electrolyzers. Key properties, including porosity and air permeability, significantly influence anode consumption and durability. This study presents the development of carbon anodes with reduced porosity and air permeability through optimized forming, sintering, and doping processes. Results revealed that using powdered pitch as a binder led to higher densification, improved flatness, and reduced porosity. Molding under a pressure of 20 MPa for 45 min further enhanced anode quality. Sintering reduced layer spacing and increased graphitization, with optimal conditions determined to be 1100 ℃ for 45 min. These conditions produced carbon anodes with maximum bulk density, minimum resistivity, and an air permeability of 2.54 nPm. The introduction of fusible B₂O₃ effectively sealed internal pores, coated the carbon substrate surfaces, and formed a protective film. This innovation reduced air permeability to 2.05 nPm and significantly enhanced the oxidation resistance of the anodes. These findings provide valuable insights into the production of high-performance carbon anodes, contributing to improved efficiency in aluminum electrolysis.

Aluminum nitride (AlN) provides excellent thermal conductivity and electrical insulation, making it suitable for semiconductor heater applications. However, its low surface emissivity can lead to thermal energy loss, reducing heater efficiency. To address this issue, black AlN - obtained by doping with carbon and other impurities to enhance the surface emissivity - has recently been applied in various fields. In this study, black AlN was fabricated by adding TiO2 to AlN, and its densification behavior and electrical properties were evaluated to assess the feasibility of its use as a heater material for semiconductor photolithography. The sinterability of black AlN was improved by optimizing the granulation and forming conditions, with a particular focus on the heat treatment parameters that affect material properties such as color. Consequently, a black AlN heater material with a sintered density of 3.33 g/cm3, thermal conductivity of 162.7 W/m･K, and thermal diffusivity of 64.22 mm2/s was fabricated by optimizing the processing variables.

This study investigates the vibration characteristics of an aluminum subframe for small and high-speed vessels through modal and resonance analysis using the finite element method (FEM). Due to the low stiffness and damping of aluminum, concerns arise over structural resonance and fatigue. A 3D model based on actual design drawings was analyzed to extract six natural frequencies and corresponding mode shapes. Significant deformation was observed in the first and second modes (90.65 Hz, 110.60 Hz), which may overlap with operational frequencies. The fifth mode (263.70 Hz) showed high amplitude with Y-axis concentration, indicating lateral resonance vulnerability. Deformation ratios were used to identify dominant vibrational directions. Based on the findings, design strategies such as structural reinforcement, RPM adjustment, and damping device application were proposed to improve vibration safety in the early design stage.

The use of aluminum-based hybrid metal matrix composite (HMMC) materials, especially in engine components like pistons, is intended to improve wear resistance and overall performance. Crucial tribological indicators, such as wear and friction coefficients, underscore the significance of these materials. However, present aluminum alloys have limited wear because of clustered reinforced particles and relatively high coefficients of thermal expansion (CTE), resulting in inadequate anti-seizure properties during dry sliding conditions. This research introduces a novel “Hybrid Metal Matrix Composite of Al7068 Reinforced with Fly Ash-SiC-Al2O3”. Al7068 is employed for its superior strength-to-weight ratio and specific modulus, which is ideal for components exposed to cyclic loads and varying temperatures. The integration of fly Ash (FA), silicon carbide (SiC), and alumina (Al2O3) as reinforcements enhances wear resistance, diminishes particle clustering, improves stiffness, mitigates CTE discrepancies, and fortifies the composite against strain and corrosion, thereby enhancing its overall performance. The Stir-casting method was used with optimized reinforcement percentages (10 % total), and comprehensive evaluations through wear tests and mechanical property analyses determined the composite's optimal composition. The proposed HMMC variant with the most suitable reinforcement percentage exhibited enhanced engine piston functionality, reduced wear, low deformation of 0.20 mm, and a comparatively higher ultimate tensile strength of 190 megapascals (Mpa).

In this study, we analyzed the structural and mechanical properties of aluminum foams fabricated using aluminum powders of varying sizes and mixtures. The effects of sintering and pore structure at each size on the integrity and mechanical properties of the foams were investigated. Structural characteristics were examined using scanning electron microscopy and micro–computed tomography, while mechanical properties were evaluated through compression testing. The experimental results demonstrated that smaller powder sizes improved foam integrity, reduced porosity and pore size, and resulted in thinner cell walls. In combination, these effects increased compressive strength as the powder size decreased. The findings of this study contribute to the understanding and improvement of the mechanical properties of aluminum foams and highlight their potential for use in a wide range of applications.

The present study introduces a machine learning approach for designing new aluminum alloys tailored for directed energy deposition additive manufacturing, achieving an optimal balance between hardness and conductivity. Utilizing a comprehensive database of powder compositions, process parameters, and material properties, predictive models—including an artificial neural network and a gradient boosting regression model, were developed. Additionally, a variational autoencoder was employed to model input data distributions and generate novel process data for aluminum-based powders. The similarity between the generated data and the experimental data was evaluated using K-nearest neighbor classification and t-distributed stochastic neighbor embedding, with accuracy and the F1-score as metrics. The results demonstrated a close alignment, with nearly 90% accuracy, in numerical metrics and data distribution patterns. This work highlights the potential of machine learning to extend beyond multi-property prediction, enabling the generation of innovative process data for material design.

Friction Stir Spot Welding (FSSW) is a solid-state welding technology that is rapidly growing in the automotive industry. Achieving superior welding characteristics requires the proper selection of tool geometry and process conditions. In this study, FSSW was performed on dissimilar materials comprising AA5052-HO/hot-melt aluminum alloy sheets and Steel Plate Cold Rolled for Deep Drawing Use(SPCUD) steel sheets. The effects of tool geometry, plate arrangement, and tool plunge depth on the welding process were investigated. At the joint interface between the aluminum alloy and the steel sheet, new intermetallic compounds (IMCs) were observed. As the plunge depth increased, thicker and more continuous IMC layers were formed. However, excessive plunge depth led to discontinuous layers and cracking defects. An analysis of the IMCs revealed a correlation between the IMC thickness and the shear tensile load. Furthermore, compared to the conventional Al-Top arrangement, the St-Top arrangement exhibited reduced deformation and superior shear tensile load values. These findings indicate that plate arrangement significantly influences the mechanical properties of the joint.

Lightweighting is crucial in various industries, especially for bicycles where weight and stiffness are key. Traditional materials like steel, aluminum, and carbon each have pros and cons. This study compares hybrid tubes made of aluminum and carbon composites with conventional aluminum tubes. Using structural analysis and experimental testing, the hybrid tubes showed a weight reduction of up to 17.25% and maintained acceptable deformation levels. Finite element analysis confirmed these findings, demonstrating the hybrid tubes' potential as superior bicycle frame materials. Future research should focus on long-term durability and fatigue characteristics.

The heat transfer characteristics of double-pipe spiral heat exchanger using aluminum oxide nano-fluid were investigated by three different sizes of curvature size, experimentally. Five concentration of nano-fluid as working fluid were made and tested to analyze the heat transfer characteristics. As results, the heat transfer performance was improved at 0.25% of nano-fluid due to high thermal conductivity, however, as the concentration of nanofluid increased (~2.0%), the heat transfer performance deteriorated due to the increase in thermal resistance caused by the sedimentation of particles in the flow path. In addition, the nano-fluid has a higher pressure drop than water due to its high density and viscosity. The optimal range for heat transfer enhancement of nano-fluid was found to be less than 4.0 LPM in flow rate and 0.25% of nano-fluid concentration in this study.

Automobiles are an essential means of transporting passengers and cargo, but traffic accidents are inevitable in their operation. These accidents can occur in various forms, such as front, rear, and side collisions. The resulting damage to the vehicle can also be seen similarly; it is inherently distinct: the complexity of repairing the car body makes a simple reliance on textbook knowledge insufficient. Successful correction of the damaged body largely depends on the experience of the practitioner. Discussions on body repair techniques should be based on empirical data reflecting current industry standards and associated costs. The variability of individual repair methodologies can result in significant time and financial expenditure in the field of automotive bodies. Application of new material technologies to vehicle fabrication requires continuous training and empirical research, especially on the body repair process involving new materials. In particular, since the left and right aprons and side members are made of different materials, such as aluminum and high-strength steel, careful restoration of these parts is required. Technical considerations are needed. Interest in safety and environmental impacts. In this study, SPR bonding technology analyzes experimental results.

현재 우리나라 연안에서 어업활동을 하고 있는 어선의 재질은 거의 FRP로 구성되어 있으며 환경개선을 고려하여 재활용이 가 능한 알루미늄 소재의 어선으로 대처를 하고 있는 실정이다. 현재 국내의 알루미늄 연안 어선의 경우 한국 해양교통 안전공단과 해수부 를 통하여 승인이 이루어져 건조를 수행한다. 우리나라의 알루미늄 연안어선의 경우 선체와 하우스의 크기에 따라 톤수 규정을 준수하며 이에 따라 형상을 정의한다. 이는 선박을 건조함에 따라 초기 선주 요구조건에 중요한 역할을 가지며 구조에 대한 하중값을 바탕으로 규 정에 만족하는 두께를 산정을 하여 선박구조를 정의할 수 있다. 국내 어선의 어업 활용 면적에 대하여 갑판 면적을 최대한 활용할 수 있 는 카타마란 알루미늄 어선의 설계 방법 및 방향을 제시하였으며 기존 연구자료의 중․소형선박의 설계 및 구조에 대한 설계 안전성을 위해 적용하였으나 본 논문은 알루미늄 어선의 구조적 형상 고찰에 따라 설계하중을 적용하고 연결 부위의 강도 해석을 수행하여 선박에 대한 안전성을 확보하여 9.77톤급 알루미늄 카타마란 선박에 대한 설계방법 및 방향을 제시하고자 한다.

As environmental concerns escalate, the increase in recycling of aluminum scrap is notable within the aluminum alloy production sector. Precise control of essential components such as Al, Cu, and Si is crucial in aluminum alloy production. However, recycled metal products comprise various metal components, leading to inherent uncertainty in component concentrations. Thus, meticulous determination of input quantities of recycled metal products is necessary to adjust the composition ratio of components. This study proposes a stable input determination heuristic algorithm considering the uncertainty arising from utilizing recycled metal products. The objective is to minimize total costs while satisfying the desired component ratio in aluminum manufacturing processes. The proposed algorithm is designed to handle increased complexity due to introduced uncertainty. Validation of the proposed heuristic algorithm's effectiveness is conducted by comparing its performance with an algorithm mimicking the input determination method used in the field. The proposed heuristic algorithm demonstrates superior results compared to the field-mimicking algorithm and is anticipated to serve as a useful tool for decision-making in realistic scenarios.

Composites of carbon quantum dots (CQDs) are important materials to utilize the optical properties of CQDs in diverse applications including photoluminescence-based sensing and LED phosphors. Combining pre-prepared CQDs with a polymeric matrix usually causes changes in the optical properties of CQDs due to unavoidable aggregation. Recently, the preparation of composites based on in-situ formed CQDs has been debated to overcome the aggregation limits of the conventional mixing methods. Herein, we have demonstrated the synthesis of homogeneous CQDs composites by simple thermal annealing blends of aluminum hydroxide (AlOH), citric acid (CA), and urea (URA). Transmission electron microscopy (TEM), X-ray diffraction, and Raman spectroscopy studies revealed the formation of individual CQDs with a diameter of about 2–9 nm dispersed homogeneously over the AlOH matrix. The composites have a broad excitation band centered at about 360 nm and exhibit excitation-dependent photoluminescence which was similar to that of hydrothermally synthesized CQDs from CA and URA. The photoluminescent intensity of the composite was stable to UV irradiation and responded selectively to Cu(II) ion demonstrating its potential application in Cu(II) sensing.