Advanced Engineering Materials最新文献

A new preparation technology for titanium matrix composites is proposed: interlayer laser cladding of SiC ceramic particles is carried out during the process of arc-directed energy deposition (ADED) technology for preparing Ti-6Al-4V additive manufacturing components. This technology is named laser cladding-ADED (LC-ADED). The microstructure and electrochemical properties of the ADED specimens and LC-ADED specimens are analyzed, and the corrosion resistance mechanism is discussed. During the LC-ADED process, the growth of α phase and prior-β grains is hindered by the precipitated eutectic TiC and Ti₅Si₃. The results of open circuit potential, polarization curve, and electrochemical impedance spectroscopy are in accordance. In terms of the corrosion resistance change trend, the order from high to low is as follows: the top LC-ADED specimens > the bottom LC-ADED specimens > the top ADED specimens > the bottom ADED specimens. Overall, the LC-ADED specimens exhibit excellent corrosion resistance.

In recent years, the demand for efficient and sustainable photodetectors has significantly increased due to their critical role in optical sensing, communication, and imaging applications. As the field of optoelectronics advances, there is an urgent need to develop cost-effective, environmentally friendly alternatives to conventional lead-freeperovskite based photodetectors, which pose toxicity concerns. In this work, a novel self-powered photodetector based on a heterojunction structure formed between Cs₂CuBr₄ and Cs₃Bi₂Br₉, fabricated via a solution-processed method has been proposed. This innovative device architecture enables efficient charge separation and transport, leading to enhanced photodetection performance. The developed self-powered photodetector demonstrates notable performance characteristics, achieving a responsivity of 2.73 × 10⁻⁵ A W⁻¹ and a specific detectivity of 3.63 × 10⁷ Jones under an illumination intensity of 100 mW cm⁻². Additionally, the device exhibits rapid photoresponse dynamics, with a rise time of 0.15 s and a fall time of 0.29 s, highlighting its potential for real-time photodetection applications. These findings suggest that the Cs₂CuBr₄/Cs₃Bi₂Br₉ heterostructure is a highly promising material system for the development of cost-effective, high-performance, and environmentally friendly self-powered photodetectors, paving the way for future advancements in sustainable optoelectronics.

Carbon nanotube fibers (CNTF) offer great properties for smart textiles, including low density, high strength, and electrical conductivity. However, the dense structure of traditional CNTF limits phase change material (PCM) loading, impeding thermal management applications. Here, this study presents a strategy to fabricate highly oriented porous CNTF (PCNTF) as flexible frameworks for dual-mode thermal regulation. The horizontally aligned carbon nanotube (CNT) architecture provides exceptional axial thermal conductivity (51.52 W m⁻¹ K⁻¹), while the hierarchical porous structure enables a high PCM loading capacity of 73.8%. High-strength PCNTF with a strength of 450.2 MPa and 6.16% strain is integrated into woven textiles, resulting in lightweight, robust composite phase change textiles. These textiles demonstrate bidirectional thermal regulation, rapid electrothermal response (55.9 °C under 0.36 W cm⁻²) and sustained passive thermal buffering, maintaining a 3–7 °C temperature differential relative to polyester in the range of 40 to 80 °C for over 300 s. This work offers a versatile platform for next-generation smart textiles with integrated active and passive thermal management capabilities.

Plasma-assisted hybrid friction stir welding (P-HFSW) is a modification of conventional FSW that employs a low-cost plasma torch as a localized preheating source to improve solid-state joining of dissimilar metals. This study develops a P-FSW setup for joining AA1100 aluminium to pure copper and examines the influence of plasma current, torch–tool offset, tool rotation, and traverse speed on thermal field, welding forces, microstructure, intermetallic compound (IMC) formation, and mechanical properties. Thermal and force measurements show that plasma preheating increases advancing-side peak temperatures by 40–110 °C (up to ≈384 °C) while reducing axial and traverse forces by 30%–35% (from ≈8.1 kN to ≈5.3 kN under optimized conditions). Mechanical testing indicates major improvement with plasma: the nonpreheated joint (Experiment 1) achieved ≈42 MPa tensile strength (≈29% of Al), whereas the optimized preheated condition (Experiment 4, 55 A) reached ≈140 MPa (≈96% of Al), a ≈230% increase. Ductility also improved as elongation rose from <4% to >8%, showing a transition from brittle to ductile fracture. Optical, scanning electron microscopy, and X-ray diffraction analyses confirm refined equiaxed grains, a uniform controlled IMC layer, and CuAl₂, CuAl, and Cu₉Al₄ phases. Controlled plasma heating enables balanced diffusion, limits IMC growth, and produces defect-free, high-strength AlCu joints for industrial applications.

Metal matrix composite foams (MMCFs) hold significant potential for aerospace and automotive applications due to their lightweight nature, high strength, and excellent energy absorption. This study aims to enhance the microstructure and mechanical properties of magnesium–aluminum (Mg–Al) matrix composite foams by incorporating nickel-coated hollow glass microspheres as fillers, fabricated via spark plasma sintering (SPS). The effects of sintering temperature (380–450 °C) and pressure (10–25 MPa) on the microstructure, interfacial bonding, and mechanical performance are systematically investigated. Results indicate that the nickel coating substantially strengthens the interfacial bonding between the hollow microspheres and the Mg–Al matrix, leading to a more uniform pore structure. Under the optimized sintering conditions of 450 °C and 15 MPa, the compressive strength of the nickel-coated samples reaches 220.78 MPa, marking a remarkable 56.1% improvement over the uncoated counterparts. The enhancement mechanism is attributed to the promoted elemental diffusion and metallurgical bonding at the interface facilitated by the nickel coating. This work provides valuable theoretical insight and experimental guidance for the design and application of high-performance Mg–Al based composite foams.

In this study, Mn₃O₄ and Zn-modified Mn₃O₄ thin films are synthesized on glass substrates using ultrasonic spray pyrolysis. A comprehensive analysis is performed on their structural, optical, chemical, photoluminescent, and electrochemical properties. X-ray diffraction confirmed the formation of a tetragonal hausmannite phase, with peak shifts indicating lattice distortion due to Zn incorporation. Ultraviolet–Visible (UV–Vis) analysis showed a band gap increase from 2.00 to 2.51 eV with Zn doping, alongside reduced visible-region absorbance. X-ray photoelectron spectroscopy validated the substitution of Zn²⁺ ions and provided insight into the Mn and Zn oxidation states. Photoluminescence spectra indicated reduced radiative recombination upon doping. Electrochemical evaluations using galvanostatic charge–discharge, electrochemical impedance spectroscopy, and cyclic voltammetry demonstrated significant improvement in charge storage for Zn-doped electrodes. Capacitance values increased from 25 F g⁻¹ (pure) to 93 F g⁻¹ (Zn-doped) at 10 mV s⁻¹, with a maximum value of 333 F g⁻¹ observed for 2% Zn-doped Mn₃O₄ at 1 A g⁻¹. The Zn additive enhanced both the charge transport and capacitive behavior, affirming its promise for energy-storage applications.

Ti–6Al–4V is a typical difficult-to-machine material, and cryogenic environments experimentally enhance its machinability. However, due to inadequate cooling temperature control, its mechanical responses and surface properties during cryogenic machining remain inadequately characterized, leaving critical temperature thresholds for improved machinability unascertained. This study investigates machining-induced forces and surface integrity of Ti–6Al–4V under a precisely controlled cryogenic environment (20 to −196 °C) using a custom variable-temperature cryogenic jet system. Influence of cryogenic temperature on cutting forces, surface roughness (R_a), residual stress, and microstructure is examined at cutting speeds V_c (40–80 m min⁻¹). Results indicate axial force reverses from tensile to compressive at −60 °C, with a second reversal to tensile below this temperature. R_a reaches minima at −100 °C (V_c = 60/80 m min⁻¹) and −140 °C (V_c = 40 m min⁻¹), with reductions up to 19.2%. Compressive residual stress magnitude increases monotonically with decreasing temperature. Microstructure evolves from acicular α-phase (conventional cooling) to lamellar colonies at moderate cryogenic temperatures (−50 to −100 °C), and finally to chaotic basketweave structures under ultracryogenic conditions (−150 to −196 °C). This work reveals cryogenic mechanisms governing Ti–6Al–4V machining behavior, identifies critical temperature thresholds, and demonstrates significant potential of the developed variable-temperature system in advancing cryogenic machining research.

Metallic-glass composites (MGCs) combine the strength and hardness of MGs with the ductility, toughness, and fatigue resistance of crystalline materials. This study focuses on developing Fe-based in situ dendritic MGCs in the (Fe, Ni)–Mo–B–C system with pseudo-equilibrium phase distributions. The alloy design strategy involves tailoring the liquid compositional partitioning to allow the formation of a MG phase with the quench rates employed and to control the composition of the primary crystalline phase. The alloy's Fe–Ni ratio is fixed to tailor the elastic “softness” of the dendrites, and the B content is varied to achieve different microstructural length scales and volume fractions of crystalline and glassy phases. Splat quenching is used to perform alloy development and create thin sheets of the MGCs. These were then characterized by X-ray diffraction, microhardness, and ribbon tensile testing. Compositions with ≥3.5 at.% B formed MGCs with crystalline dendrites and an amorphous phase, showing improved ductility and achieving strain hardening in the thin sheets.

Electrically conductive inks are important to the progress of flexible electronics, wearable systems, and soft robotics due to their low cost, lightweight design, and compatibility with scalable printing. Traditional formulations based on silver or copper particles, carbon materials, or conductive polymers have achieved significant advances but remain constrained by tradeoffs between conductivity, flexibility, and processing. Liquid metal inks combine fluidity, metallic conductivity, and self-healing ability, yet the high filler content and environmental instability constrain broader application. To overcome these barriers, the concept of platform-type conductive inks is emerging as a framework that balances electrical performance, processability, structural adaptability, and system functionality. This approach shifts attention from material-specific optimization toward programable ink architectures that can serve diverse applications without fundamental reformulation. Future opportunities include universal printability, dynamic structural reconfiguration triggered by external stimuli, sustainable recycling strategies, and the integration of sensing or actuation functions. By advancing along these directions, conductive inks can evolve from passive conductors into adaptive and multifunctional material platforms, providing the foundation for next-generation printed and reconfigurable electronics.

Owing to their efficient multifunctional responses, multiferroics have secured a notable position for use in sensors, memory, and spintronic devices. Herein, highly crystalline forms of BiFeO₃, PbZr_0.58Ti_0.42O₃, and MnFe₂O₄ are obtained through hydrothermal, solid-state, and sol–gel autocombustion methods, respectively. A triphasic composite series with the formula 0.9[(1–x)BiFeO₃ + xPbZr_0.58Ti_0.42O₃ + 0.1MnFe₂O₄ (x = 0.0–0.3, interval 0.1) is then prepared using the solid-state route. X-ray diffraction confirms the coexistence of rhombohedral-distorted perovskite phases (BiFeO₃ and PbZr_0.58Ti_0.42O₃) alongside the cubic spinel phase (MnFe₂O₄). Field-emission scanning electron microscopy reveals porous surfaces with spherical and irregular grain morphologies. Ferroelectric analysis demonstrates a maximum polarization of 3.736 × 10⁻³ μC cm⁻², with the highest energy-storage efficiency of 70.76% and minimal energy loss density (0.1498 μJ cm⁻³) for the x = 0.2 composition, making it suitable for energy storage and memory applications. Positive-up negative-down analysis confirms significant variations in switching charge density across all composites. Meanwhile, magnetic hysteresis studies demonstrate soft ferromagnetic behavior dominated by the MnFe₂O₄ phase, with optimal response in x = 0.3 sample with M_max ≈ 0.38 emu g⁻¹, M_r = 0.019 emu g⁻¹, and H_c = 160 Oe. By harnessing these parameters, the x = 0.2 composition emerges as optimal for energy storage, while the x = 0.3 composition stands out for magnetic device applications.