Advanced Engineering Materials最新文献

Harvesting wind and solar energy in marine environments to power marine sensors has become a hot research topic. Herein, a marine hybrid energy gathering method based on codoped microthermoelectric generator (MTEG) and charge-enhanced triboelectric nanogenerator (TENG) is proposed. A prototype based on this method is designed. It consists of an MTEG unit made from codoped Bi₂Te₃-based thermoelectric materials and a TENG unit equipped with a charge density enhancement circuit. This prototype can simultaneously harvest solar energy and wind energy in marine environments to power marine sensors. The prototype can generate a voltage output of 72 V and a power output of 90.5 μW under experimental conditions featuring a wind velocity of 5 m s⁻¹ and a temperature difference of 50 K. This results in a harvesting energy density of 9 W m⁻³. Based on experiments, the feasibility of the hybrid energy gathering method presented herein is verified, offering a new approach for powering marine sensors.

Microstructural stability of polycrystalline alloys depends on the motion of grain boundaries during heat treatment. The presence of second-phase particles (SPP) is one of the most effective mechanisms to stabilize the polycrystalline structure by pinning grain boundaries. The current study utilizes phase field modeling to determine the impact of particle size, morphology, and number distribution on grain growth in a face centered cubic copper system. The simulation results indicate that a distinct relationship exists between grain boundary motion and particles of different shapes. Above a minimum area fraction threshold for SPP, the number of particles per unit area emerges as the primary factor controlling the rate of grain growth. Particle shape aspect ratio shows influence on pinning grain boundaries as well with elongated particle shapes demonstrating improved grain boundary pinning, especially when oriented with the long axis parallel to the migrating grain boundary. The results presented here are in good agreement with experimentally observed trends, and the validation of a simplified phase field model allows for added complexity in future simulations.

Plasma electrolytic oxidation (PEO) is a well-established electrochemical method to modify titanium (Ti) surfaces for various industrial applications, including automobile, aerospace, nuclear, sports, defense, and biomedical industries. However, PEO surfaces, with their subsequent nanostructural modification to achieve enhanced antibacterial properties, osseointegration, and biocompatibility on biomedical implants are barely explored. This study investigates the combined approach of PEO and hydrothermal (HT) processes to introduce a range of nanostructures on PEO-induced porous titania for enhanced antibacterial and improved osseointegration properties. Different fabrication conditions of combined PEO and HT process enabled the fabrication of multidimensional nano-morphologies, such as blades, needles, belts, and grass that exhibit mechano-bactericidal properties with enhanced biocompatibility. Antibacterial performance shows that nanostructures generated using HT on the acidic PEO process have excellent antibacterial activity, destroying 88% of E. coli and ≈99% of S. aureus colonies after 24 h incubation. All these fabricated structures show very high biomineralization ability, as confirmed by simulated body fluid (SBF) tests. This study provides valuable contributions showing the potential of low-cost PEO technology combined with other surface engineering methods for scalable modification and improvements of titanium implants with advanced antibacterial and biointegration properties.

The dynamic recrystallization (DRX) behavior and hot workability of Mg–8Gd–4Sm–1Zn–0.5Zr alloys are investigated by the Gleeble-1500 test machine. The tests are performed at 350–470 °C with a strain rate of 0.002–1 s⁻¹. The results show that the stress–strain curves exhibit a typical single-peak DRX behavior. The DRX critical strain model of the alloy is constructed according to the inflection characteristics of the work hardening rate curve. The DRX kinetic model is constructed according to Avrami equation. The 3D processing maps are obtained based on the dynamic material model. The mechanisms of instability regions are investigated by combining the processing map and the microstructural evolution, and the most suitable regions for hot working are identified. The critical strain ε_c of the alloy is reduced at higher deformation temperatures or lower strain rates, and the DRX more easily occurs. That is, the material is more suitable for hot working. The optimum domain for hot working of Mg–8Gd–4Sm–1Zn–0.5Zr alloy is the temperature range of 400–470 °C and strain rate range of 0.002–0.05 s⁻¹.

The adoption of biobased polymers is growing in the additive manufacturing industry, offering alternatives to petrochemical-based plastics, known for their environmental impact. However, finding a single polymer with all desirable properties is challenging. Blending polymers allows for the combination of distinct features, optimizing performance for specific applications. This study formulates two biopolymer blends of poly(butylene succinate) (PBS) and poly(lactic acid) (PLA) (80/20 wt%) using different PBS grades to examine their effects on thermomechanical and functional properties. The addition of PLA, a shape memory polymer, enables dynamic changes in 3D printed structures, causing them to deform under stimuli and revert to their original shape—an effect known as 4D printing. The blend pellets are then used in filament extrusion, and smart sandwich samples are produced using fused filament fabrication. The thermomechanical and functional characteristics of the printed samples are evaluated. This research highlights the differences arising from using different PBS grades in 3D printed structures with high energy absorption. Results show that melt flow rate is a crucial factor, significantly affecting the thermomechanical and shape memory behavior, with variation between 86% and 93%.

The anodized aluminum oxide prepared by anodizing is the core of aluminum electrolytic capacitors, and its quality determines the performance of aluminum electrolytic capacitors. The traditional direct current (t-DC) anodizing method commonly used in industrial production today with low current density has the problems of low anodizing efficiency, poor crystallinity, and high formation constants of the oxide film. However, high current density direct current anodizing has the problems of severe defects of the oxide film and much thermal dissolution of aluminum foil. Herein, the dual-phase enabled sinusoidal current (DESC) anodizing method is proposed for the preparation of 200 V anodized aluminum foil with much higher efficiency and performance. After testing, it is found that the alumina prepared by the DESC method has higher crystallinity and fewer defects. Consequently, the specific capacitance of the DESC sample is 23% greater than that of the t-DC anodized sample, while the former displays a lower loss angle tangent and leakage current. Meanwhile, DESC anodizing takes 60% time less than t-DC anodizing due to its high current density. The DESC anodizing method has been identified as a promising avenue for further investigation, exhibiting high efficiency and performance.

The 3D-braided composites have been widely used in aerospace and other fields due to the excellent mechanical properties, designability, and resistance to delamination. Accurately analyzing and evaluating mechanical properties of braided composite structures is the key, which successfully designs related structural components. However, 3D-braided composites have complex internal meso–microscopic structures, and directly establishing a solid structure model to predict mechanical behavior poses certain challenges. The multiscale research methods are a type of approach that studies the cross-scale structural characteristics at macro–meso–microscopic scales and couples relevant scales into a whole. Its emergence provides the possibility for evaluating the overall structural performance of 3D-braided composites. In this article, first, the multiscale analysis models of 3D-multidirectional-braided composites are reviewed, and then the theoretical and numerical research progress on the static and dynamic multiscale mechanical performance of regular components of 3D-braided composites is summarized. In addition, due to the distortion and variation of geometric shapes of 3D-braided composites on the meso–microscopic structure; therefore, also in this article, the research progress on multiscale mechanical performance characteristics of special-shaped components is summarized. Finally, the key problems in the multiscale research of 3D-braided composites are presented.

Interfaces in metal matrix composites (MMCs) are crucial in determining the mechanical properties and functionality of MMCs. This article reviews recent scientific advances and issues related to MMC interfaces from four different perspectives: interfacial structural design, interfacial defect control, thermodynamics and kinetics of interfacial reactions, and interfacial microstructure properties-based numerical simulation. The influence of interfacial microstructural features on interfacial strength–toughness trade-offs and their functionality is given special attention. The interfacial problem is still one of the main challenges to be solved in the composite system, which is mainly reflected in the following aspects: interfacial microstructure–deformation mechanisms in complex systems, precise control of interfacial defects and interfacial reaction products, and the efficient and cost-effective application of numerical simulation techniques. The integrated computation and intelligent design (artificial intelligence) of composites through multiscale computational simulation with the guidance of “interface design-property prediction” will be the key area of MMC interface research in the future.

Over 70% of pharmaceutical compounds face the challenge of poor water solubility, which impacts on their bioavailability. This study focuses on the use of Santa Barbara Amorphous-15 (SBA-15) mesoporous silica material as carrier, which is synthesized and characterized to address this limitation. Albendazole (ABZ), an antiparasitic agent with low water solubility, serves as model drug. A Box-Behnken design (BBD) is used to investigate the impact of immersion method loading factors (temperature: 25–50 °C, time: 24–72 h, and SBA-15 amount: 83.2–252.0 mg) on drug loading percentage (DL%) and dissolution efficiency (DE%). The ABZ loading is confirmed by elemental analysis and Fourier transform infrared spectroscopy. Stability tests are performed, comparing drug dissolution profiles and X-ray diffraction patterns immediately after loading and after 12 months of storage at 25 °C and 60% relative humidity (RH%). DL% varies between 18% and 36% (w/w), showing that the amount of SBA-15 is the most significant factor on DL%. The lowest SBA-15 amount yielded the highest DL%. Regarding DE%, all the design samples exhibit higher values than pure ABZ, with the amount of SBA-15 being the primary influencing factor. Several samples from the BBD show high DE% (>70%) corresponding to high DL% values. After 12 months, most samples maintain similar dissolution profiles, demonstrating the good stability of the drug in the carrier over time. This study provides valuable insights into optimizing the loading process to enhance ABZ solubility and long-term stability using mesoporous SBA-15.

ZGH451, a directionally solidified Ni-based superalloy designed for additive manufacturing, has garnered significant attention in the realm of next-generation turbine blades. Welding the ZGH451 superalloy is crucial for promoting its practical application. In this study, transient liquid phase (TLP) bonding is applied to weld ZGH451 superalloy produced through directed energy deposition. A Ni-based interlayer alloy powder is developed and prepared via thermodynamic calculation, with the interlayer subsequently characterized using differential thermal analysis. TLP bonding is conducted at 1200 °C for 4 h. The influence of the preset gap on the joint microstructure and mechanical properties is examined. The microstructure of the TLP bonding joints comprises athermally solidified zones (ASZ), isothermally solidified zones, and diffusion-affected zones. The ASZ width significantly increases with the growing preset gap. A preset gap not exceeding 100 μm enables complete isothermal solidification of the joints. Particularly, joints with a preset gap ranging from 0 to 30 μm demonstrate optimal reliability, exhibiting a tensile strength of up to 1375 MPa at room temperature, which is 12% higher than the room temperature strength of the base metal (BM), and a tensile strength of 983 MPa at 760 °C, surpassing 86% of the BM's strength at the same temperature.