This study compares the microstructure and properties of pure Cu and Cu-5 wt.% Al2O3 composites fabricated by spark plasma sintering under strictly identical processing conditions at 800-1000°C. Pure Cu samples achieved near-full densification and exhibited a bimodal grain structure dominated by coarse grains with increasing sintering temperature. In contrast, the composite samples showed lower density and non-monotonic densification behavior, with a minimum relative density at 900°C and significantly refined equiaxed grains due to strong grain-boundary pinning by nano Al2O3 particles. The higher fractions of high-angle boundaries and pronounced orientation disruption were observed in the composite samples, while high-resolution analysis confirmed the presence of grain-boundary Al2O3-rich regions that restricted Cu grain coalescence and continuity of grain boundary migration. X-ray diffraction results confirmed the absence of reaction phases in both materials. Hardness peaked at 900°C for both samples, and the composite samples showed consistently lower hardness due to retained porosity. The apparent electrical conductivity of the composite displays a non-linear temperature dependence, reflecting the competing influences of densification, microstructural recovery, and the insulating nature of Al2O3.

Al–Mg co-doped ZnO thin films were fabricated by a sol–gel spin-coating process to investigate the effect of dopant ratio on their structural, electrical, and optical properties. The total dopant concentration was fixed at 3 mol%, while the Al-to-Mg ratio was systematically varied in AlxMg0.03-xZn0.97O (0 ≤ x ≤ 0.03). X-ray diffraction analysis showed that the films maintained a hexagonal wurtzite structure with a preferred (002) orientation up to an Al concentration of 1.5 mol%, whereas higher Al contents resulted in a degradation of crystallinity due to exceeding the solid solubility limit of Al in the ZnO lattice. Hall effect measurements revealed a decrease in carrier mobility with increasing Al content, attributed to enhanced ionized impurity scattering, while the carrier concentration and electrical conductivity reached optimal values at an Al–Mg co-doping ratio of 1.5 mol%–1.5 mol%. All films exhibited high optical transmittance in the visible region, with the highest average transmittance of approximately 83% observed at the same composition. These results demonstrate that controlling the Al/Mg dopant ratio is crucial for optimizing the performance of ZnO-based transparent conducting oxide thin films.

Due to the severity of environmental degradation and depletion of natural energy resources, research on sustainable energy storage systems have become quite popular. Supercapacitor is one of the most innovative and promising type of energy storage devices. The effective performance of supercapacitor greatly depends on the electrode material. Therefore, new type of nanocomposite has been fabricated with βCD-stabilized CuO nanoparticles (CuO-βCD NPs) on Co-Al layered double hydroxide (Co-Al LDH) utilizing solvothermal process. The wet impregnation technique facilitates the formation of three distinct CuO-βCD/Co-Al LDH nanocomposites in the ratios of 1:1, 1:2, and 2:1 by promoting the growth of CuO-βCD on Co-Al LDH in corresponding compositions. Synthesized nanocomposites are characterized using a variety of spectroscopic techniques. The average pore size of 2:1 CuO-βCD/Co-Al LDH is 1.7 nm whereas the specific surface area and approximate pore volume of this nanocomposite are 38.306 m2 g− 1 and 0.043 cm3 g− 1, respectively. Electrochemical investigations like cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), electrochemical impedance spectroscopic (EIS) measurements and along with cycle stability studies are performed to examine the electrochemical performance of synthesized nanocomposites. The 2:1 ratio has revealed improved specific capacitance (SC) of 1567 F g− 1 at 0.45 A g− 1 in 1 M potassium hydroxide medium in three electrode systems and maintains 76% of its original SC even after 5000 cycles. The improved electrochemical performance of 2:1 ratio reveals the appropriateness of this material as an effective electrode for supercapacitor application.

This study compares the optical and radiative cooling performance of single-layer films embedded with TiO2 or Al2O3 nanoparticles dispersed in a polymer matrix and backed with an aluminum reflector. Optical constants of both materials were obtained from literature, and wavelength-dependent scattering efficiencies were calculated using Mie theory. A Monte Carlo ray-tracing simulation was performed to evaluate the spectral reflectance, absorptance, and emissivity of each film across the solar and thermal-infrared regions. The TiO2-based film exhibited strong visible-light scattering but suffered significant ultraviolet (UV) absorption, resulting in an average solar reflectance of ~0.90. In contrast, the Al2O3-based film showed negligible UV absorption and maintained high reflectance (> 0.95) throughout the 0.3-2.5 μm solar band, leading to a higher net cooling power of approximately 105 W/m² compared to 85 W/m² for TiO2. These results demonstrate that UV reflectance is a key determinant of effective radiative cooling and indicate that Al2O3-based coatings offer strong potential for passive cooling applications in buildings and agricultural environments.

In this study, Cu was added in amounts of 0, 0.5, and 1 wt% to Al-1Zn-0.5MM-0.3Mg alloys to investigate its effects on phase formation, microstructural evolution, recrystallization behavior, and mechanical properties under as-cast and extruded conditions. Additional Al2Cu phases appeared with increasing Cu addition. EBSD (electron backscatter diffraction) analysis of the extruded alloys revealed that the average grain size boundaries [HAGB (high angle grain boundary), > 15°] increased from 0.124 to 0.299, confirming recrystallization was significantly enhanced by the addition of 1 wt% Cu. Furthermore, the maximum ODF(orientation distribution function) intensity decreased from 6.597 to 3.88 (M.R.D.), indicating that the crystallographic texture became more randomized as recrystallization progressed. Tensile testing showed that the yield strength (YS) and ultimate tensile strength (UTS) increased from 56.28 to 62.28 MPa and from 91.58 to 152.73 MPa, respectively, due to grain refinement and both solid-solution and precipitation strengthening by Cu. These findings demonstrate that adding Cu effectively controls phase formation, recrystallization, and mechanical properties in Al-Zn-MM-Mg alloys.

Silicon based anode materials offer high theoretical capacity but suffer from severe volume expansion and unstable interfacial properties during repeated lithiation and delithiation, resulting in rapid performance degradation. In this study, a thin aluminum oxide coating layer was deposited on Si/SiOx Carbon anode materials using a powder atomic layer deposition (PALD) process to address these limitations. EDS mapping and XRD analyses confirmed the uniform formation of an amorphous aluminum oxide coating with increasing thickness as the deposition cycles increased. Electrochemical evaluation showed that the electrode coated with 5 PALD cycles exhibited approximately 78% higher capacity retention after 100 cycles at 1 A g-1 and a higher initial Coulombic efficiency compared to the bare electrode. The coated electrode also delivered approximately 22% higher capacity at a high current density of 5 A g-1, indicating enhanced rate capability. Cyclic voltammetry analysis revealed increased surface controlled reaction contributions and improved reaction kinetics. These results demonstrate that PALD derived aluminum oxide coatings effectively stabilize the electrode electrolyte interface and enhance the electrochemical performance of silicon based anodes, highlighting their potential for next generation high capacity lithium ion batteries. generation high capacity lithium ion battery anode materials.

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.

This study prepared a (TiO2-CeO2)/Sr4Al14O25: Eu2+,Dy3+ heterojunction photocatalyst by coating (TiO2-CeO2) nanoparticles on a Sr4Al14O25:Eu,Dy phosphor substrate using a hydrothermal reaction method. The fabricated (TiO2- CeO2)/Sr4Al14O25: Eu2+,Dy3+ composites were characterized with X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photo electron spectroscopy (XPS), UV-visible diffuse reflectance spectroscopy (UV/Vis DRS), Brunauer-Emmett-Teller (BET), and Raman spectroscopy. The photocatalytic performance of the (TiO2-CeO2)/Sr4Al14O25: Eu2+,Dy3+ composites was investigated through the decomposition of toluene gas for various ratios of TiO2 to CeO2 (3:7, 5:5, and 7:3) and heat treatment ranging from 300 to 700 °C. The coupling between (TiO2-CeO2) and the highly persistent Sr4Al14O25:Eu2+,Dy3+ phosphor reduced the energy band gap and enhanced visible light absorption. In particular, the 5:5 ratio of TiO2 to CeO2 on Sr4Al14O25:Eu2+,Dy3+ showed excellent photocatalytic performance, decomposing over 85 % of the toluene gas within 150 min even under visible-light irradiation. The results suggest that the CeO2 particles might increase the specific surface area, and effectively suppress the recombination of electrons and holes generated from TiO2, thereby enhancing the photocatalytic reactivity.

This study examined process–structure relationships in laser powder bed fusion of Al0.1CoCrFeNi + Cu composites, focusing on densification, elemental distribution, and solidification cracking. Mechanically mixed Al0.1CoCrFeNi and Cu powders were processed across a range of laser powers (100–250 W) and scan speeds (200–800 mm/s). Increased volumetric energy density (VED) improved densification, with a plateau near 200 J/mm3 yielding ~96% relative density; however, this value was still below application-grade thresholds. At low VED, insufficient thermal input and short melt pool residence times promoted Cu segregation, while higher VED facilitated improved elemental mixing. Elemental mapping showed partial co-segregation of Ni with Cu at low energies. Solidification cracks were observed across all processing conditions. In high VED regimes, cracking exhibited a minimal correlation with segregation behavior and was primarily attributed to steep thermal gradients, solidification shrinkage, and residual stress accumulation. In contrast, at low VED, pronounced Cu segregation appeared to exacerbate cracking through localized thermal and mechanical mismatch.

High-entropy alloys (HEAs) incorporating low-melting-point elements (Mg and Al) and high-melting-point elements (Ti, Cr, and V) were fabricated via mechanical alloying and spark plasma sintering. Sintering temperatures were varied to investigate phase behavior and microstructural evolution. X-ray diffraction was used to identify phase structures, scanning electron microscopy to analyze microstructures, X-ray fluorescence to determine elemental composition, and a gas pycnometer to measure density. Micro-Vickers hardness testing was conducted to evaluate mechanical properties. Mechanical-alloyed HEAs exhibited a body-centered cubic (BCC) phase and lamellar structures with element-enriched regions. Sintering introduced additional BCC and Laves phases, while higher temperatures promoted Mg liquid-phase sintering, increasing density and hardness. This study highlights the effects of sintering on HEAs containing elements with differing melting points to optimize their properties.

Ti-6Al-4V alloy is widely utilized in aerospace and medical sectors due to its high specific strength, corrosion resistance, and biocompatibility. However, its low machinability makes it difficult to manufacture complex-shaped products. Advancements in additive manufacturing have focused on producing high-performance, complex components using the laser powder bed fusion (LPBF) process, which is a specialized technique for customized geometries. The LPBF process exposes materials to extreme thermal conditions and rapid cooling rates, leading to residual stresses within the parts. These stresses are intensified by variations in the thermal history across regions of the component. These variations result in differences in microstructure and mechanical properties, causing distortion. Although support structure design has been researched to minimize residual stress, few studies have conducted quantitative analyses of stress variations due to different support designs. This study investigated changes in the residual stress and mechanical properties of Ti-6Al-4V alloy fabricated using LPBF, focusing on support structure design.

This study focused on optimizing the digital light processing (DLP) 3D printing process for high-precision ceramic components using alumina-based slurries. Key challenges, such as cracking during debinding and precision loss due to slurry sedimentation, were addressed by evaluating the exposure time and the nano-to-micro alumina powder ratios. The optimal conditions—exposure time of 15 seconds and a 1:9 mixing ratio—minimized cracking, improved gas flow during debinding, and increased structural precision. Microchannels with diameters above 1.2 mm were successfully fabricated, but channels below 0.8 mm faced challenges due to slurry accumulation and over-curing. These results establish a reliable process for fabricating complex ceramic components with improved precision and structural stability. The findings have significant potential for applications in high-value industries, including aerospace, energy, and healthcare, by providing a foundation for the efficient and accurate production of advanced ceramic structures.

Ceramic materials have become essential due to their high durability, chemical stability, and excellent thermal stability in various advanced industries such as aerospace, automotive, and semiconductor. However, high-performance ceramic materials face limitations in commercialization due to the high cost of raw materials and complex manufacturing processes. Aluminum borate (Al₁₈B₄O₃₃) has emerged as a promising alternative due to its superior mechanical strength and thermal stability, despite its simple manufacturing process and low production cost. In this study, we propose a method for producing Al₁₈B₄O₃₃ spherical powder with increased uniformity and high flowability by controlling the particle size of B₂O₃. The content ratio of the manufactured Al18B4O33 spherical powder was Al2O3: B2O3 = 87:13, and it exhibited a 17% reduction in the Hausner ratio (1.04) and a 29% decrease in the angle of repose (23.9°) compared to pre-milling conditions, demonstrating excellent flowability.

High-frequency soft magnetic Ni, Fe, and Co-based thin films have been developed, typically as nanocrystals and amorphous alloys. These Ni, Fe, and Co-based thin films exhibit remarkably good frequency dependence up to high frequencies of several tens of MHz. These properties arise from the moderate magnetic anisotropy and fairly high electrical resistivity that result from the microstructural characteristics of the nanocrystalline and amorphous states. In this paper, Al-Co/AlN-Co and Al-N/AlN-Co multilayer films were deposited using two-facing-target type sputtering (TFTS). Their microstructures, magnetic and electrical properties were studied with the expectation that inserting Al-Co or Al-N as an interlayer could effectively reduce the coercive force and produce films with relatively high resistivity. A new approach is presented for the fabrication of Al-Co (Al-N)/AlN-Co multilayer films, prepared with the TFTS system. The deposited films were isothermally annealed at different temperatures and investigated for microstructure, magnetic properties and resistivity. The TFTS method used in this experiment is suitable for fabricating Al-Co(Al-N)/AlN-Co multilayer films with different layer thickness ratio (LTR). The annealing conditions, thickness of the multilayer film, and LTR can control the physical properties as well as the microstructure of the manufactured film. Magnetization and resistance increased and coercivity decreased as LTR decreased. The thin film with LTR = 0.175 exhibited high resistivity values of 2,500 μΩ-cm, magnetization of 360 emu/cm3, and coercivity of 5 Oe. Results suggests that thin films with such good resistivity and magnetization would be useful as high-density recording materials.

Aluminum-based composites are in high demand in industrial fields due to their light weight, high electrical conductivity, and corrosion resistance. Due to its unique advantages for composite fabrication, powder metallurgy is a crucial player in meeting this demand. However, the size and weight fraction of the reinforcement significantly influence the components' quality and performance. Understanding the correlation of these variables is crucial for building high-quality components. This study, therefore, investigated the correlations among various parameters—namely, milling time, reinforcement ratio, and size—that affect the composite’s physical and mechanical properties. An artificial neural network model was developed and showed the ability to correlate the processing parameters with the density, hardness, and tensile strength of Al2024-B4C composites. The predicted index of relative importance suggests that the milling time has the most substantial effect on fabricated components. This practical insight can be directly applied in the fabrication of high-quality Al2024-B4C composites.

This review examines the microstructural and mechanical properties of a Ti-6Al-4V alloy produced by wrought processing and powder metallurgy (PM), specifically laser powder bed fusion (LPBF) and hot isostatic pressing. Wrought methods, such as forging and rolling, create equiaxed alpha (α) and beta (β) grain structures with balanced properties, which are ideal for fatigue resistance. In contrast, PM methods, particularly LPBF, often yield a martensitic α′ structure with high microhardness, enabling complex geometries but requiring post-processing to improve its properties and reduce stress. The study evaluated the effects of processing parameters on grain size, phase distribution, and material characteristics, guiding the choice of fabrication techniques for optimizing Ti-6Al-4V performance in aerospace, biomedical, and automotive applications. The analysis emphasizes tailored processing to meet advanced engineering demands.

이 실험에서는 α-Al2O3 지지체 위에 진공 코팅(vacuum coating)과 딥 코팅(dip-coating) 기법을 사용하여 GO/γ -Al2O3 중간층을 형성하였고, 무전해도금 방식을 통해 Pd-Ag 수소 분리막을 제작하였다. Pd와 Ag는 각각 무전해도금을 통해 지지체 표면에 증착되었으며, 합금화를 위해 도금 과정 중 H2 분위기 하에서 500°C에서 18 h 동안 열처리를 진행하였다. 제 조된 분리막의 표면과 단면은 SEM을 통해 분석되었으며, Pd-Ag 분리막의 두께는 1.88 μm, GO/γ-Al2O3 중간층을 가진 Pd-Ag 분리막의 두께는 1.07 μm로 측정되었다. EDS 분석을 통해 Pd-77%, Ag-23%의 조성으로 합금이 형성된 것을 확인하 였다. 기체투과 실험은 H2 단일가스와 H2/N2 혼합가스를 이용하여 수행되었다. H2 단일가스 투과실험에서 450°C, 4 bar 조건 하에서 Pd 분리막의 최대 H2 플럭스는 0.53 mol/m²·s로, Pd-Ag 분리막의 경우 0.76 mol/m²·s로 측정되었다. H2/N2 혼합가스 실험에서 측정된 분리막의 separation factor는 450°C, 4 bar 조건에서 Pd 분리막이 2626, Pd-Ag 분리막이 13808로 나타났다.