Surface Technology (表面技术)•2026•DOI: 10.16490/j.cnki.issn.1001-3660.2026.09.001
High-speed dry cutting of hardened steel imposes severe oxidative and diffusion wear on AlCrN/TiSiN-coated tools, limiting service life. This study introduces a multilayer composite plus pre-oxidation strategy: an AlCrN/TiSiN coating deposited by arc ion plating is subjected to controlled pre-oxidation, forming an in-situ AlCrTiSiON oxide barrier. Static oxidation, high-temperature tribological tests, and dry milling of hardened 45 steel evaluate performance. After 800 °C oxidation, the AlCrN/TiSiN coating develops porous TiO/TiO2 and o-SiO2 phases, while the multilayer coating retains sharp protective oxide peaks and strong fcc-TiN/fcc-CrN reflections. Hardness peaks at 49.64 GPa after 600 °C oxidation, with H/E = 0.102 and H3/E*2 = 0.426 GPa. Critical load reaches 85 N after 700 °C oxidation. At 700 °C friction, wear rate minimizes at 2.28×10−10 mm3/(N·mm); at 800 °C, friction coefficient drops to 0.63. In dry milling, the multilayer tool achieves a wear band of only 60.66 μm after 90 min, and a cutting life 13.83 times that of uncoated and 3.46 times that of AlCrN/TiSiN-coated tools. Cutting temperature is reduced by 68 °C at 120 min compared to the AlCrN/TiSiN coating. The pre-oxidized oxide layer suppresses oxygen inward diffusion and heat conduction, enhancing structural stability and tool longevity.
China Foundry•2026•DOI: 10.1007/s41230-025-5024-y
Abstract: The unique crystallographic lamellar microstructure (CLM) Ni-based superalloys fabricated by laser powder bed fusion (LPBF) exhibits excellent tensile properties. This study aims to investigate CLM’s high-temperature stress rupture behavior and use these findings to improve the additive manufacturing process. The result shows that the high temperature-induced intergranular fracture in <110> grain region is responsible for stress rupture failure under both conditions of 760 °C/780 MPa and 980 °C/260 MPa. Among them, the sub-grain boundary fracture occurs only under high temperature and low stress, 980 °C/260 MPa. Due to the severe intergranular fracture induced by stray grains, the stress rupture life is very low under both conditions. According to the finite element simulation, the formation of stray grains stems from the unstable heat flow within the melt pool during the process. In addition, the shorter stress rupture lifetime does not excite a more pronounced dislocation network around the γ′ phase. However, the deformation twins can still be activated inside the <110> grains, so it has excellent plasticity under both test conditions. Finally, this work indicates that the future optimization of CLM by LPBF should focus on eliminating of high-angle grain boundaries in <110> grains.
China Foundry•2026•DOI: 10.1007/s41230-025-4147-5
The effects of the high pressure die casting (HPDC) processes on porosity, microstructure, and mechanical properties of heat-treatment-free aluminum silicon (Al-Si) alloys have long been a focal point in automotive die-casting research. In this work, the combined effect of shot sleeve materials and slow shot speeds on porosity, microstructure and mechanical properties of a newly designed HPDC Al-Si alloy was investigated. Results show that employing a ceramic shot sleeve or increasing the slow shot speed significantly reduces both the average size and area fraction of externally solidified crystals (ESCs), as well as the average pore size and volume fraction. When the slow shot speed is increased from 0.05 m·s-1 to 0.1 m·s-1, the pore volume fraction decreases by 10.2% in steel-shot-sleeve samples, compared to a substantial 67.1% reduction in ceramic-shot-sleeve samples. At a slow shot speed of 0.1 m·s-1, castings produced with a ceramic shot sleeve exhibit superior mechanical properties: 8.3% higher yield strength, 17.4% greater tensile strength, and an 81.4% improvement in elongation, relative to those from a steel shot sleeve. These findings provide valuable insights for minimizing porosity and coarse ESCs in die castings, offering promising potential for broader industrial applications.
Journal of Central South University•2026•DOI: 10.1007/s11771-026-6266-6
To reduce the subjectivity of conventional instability criteria in deep rock engineering, this study develops an energy-driven criterion grounded in cusp catastrophe theory and embeds it within an improved nonlinear Hoek-Brown (H-B) strength-reduction framework. We derive an explicit algebraic transformation that maps a quartic energy potential to the standard cusp form and introduce the mutation eigenvalue Δ as a physically interpretable measure of proximity to the vanishing of the energy barrier. Building on this, failure staging is diagnosed in practice by the concurrence of a slope mutation in displacement-reduction-factor curves, a threshold jump of total plastic strain-energy increment typically exceeding threefold between adjacent reduction steps, and video-confirmed crack through-connection. Integrating Δ with the nonlinear reduction scheme yields reproducible integral safety factors. Two representative cavern layouts (Model A/B) are validated by scaled physical model tests and companion simulations: global failure occurs at the overload safety factor K=2.33 for Model A and K=2.73 for Model B, with relative deviations from tests (2.4P0 and 2.9P0) of 1.3% and −5.9%, respectively, coinciding with the energy-jump threshold and the multi-evidence diagnosis. Compared with the equivalent Mohr-Coulomb parameter approach, the improved nonlinear scheme produces smaller (more conservative) safety factors by 5.7% and 2.5%, while better matching the observed destabilization process. The framework clarifies the role of Δ as an energy-based instability indicator and offers a practical, verifiable criterion for cavern stability assessment.
Nano-Micro Letters•2025•DOI: 10.1007/s40820-025-01806-0
Electrocatalyst activity and stability demonstrate a “see-saw” relationship. Introducing vacancies (Vo) enhances the activity by improving reactant affinity and increasing accessible active sites. However, deficient or excessive Vo reduces polysulfide adsorption and lowers catalytic stability. Herein, a novel “heteroatoms synergistic anchoring vacancies” strategy is proposed to address the trade-off between high activity and stability. Phosphorus-doped CoSe2 with remained rich selenium vacancies (P-CS-Vo-0.5) was synthesized by producing abundant selenium Vo followed by controlled P atom doping. Atomic-scale microstructure analysis elucidated a dynamic process of surface vacancy generation and the subsequent partial occupation of these vacancies by P atoms. Density functional theory simulations and in situ Raman tests revealed that the Se vacancies provide highly active catalytic sites, accelerating polysulfide conversion, while P incorporation effectively reduces the surface energy of Se vacancies and suppresses their inward migration, enhancing structural robustness. The battery with the optimal P-CS-Vo-0.5 separator delivers an initial discharge capacity of 1306.7 mAh g−1 at 0.2C, and maintain 5.04 mAh cm−2 at a high sulfur loading (5.7 mg cm−2, 5.0 μL mg−1), achieving 95.1% capacity retention after 80 cycles. This strategy of modifying local atomic environments offers a new route to designing highly active and stable catalysts.
Nano-Micro Letters•2025•DOI: 10.1007/s40820-025-01795-0
Historically seen as a limitation, grain boundaries (GBs) within polycrystalline metal halide perovskite (MHP) films are thought to impede charge transport, adversely impacting the efficiency of perovskite solar cells (PSCs). In this study, we employ home-built confocal photoluminescence microscopy, combined with photocurrent detection modules, to directly visualize the carrier dynamics in the MHP film of PSCs under real operating conditions. Our findings suggest that GBs in high-efficiency PSCs function as carrier transport channels, where a notable enhancement in photocurrent is observed. Femtosecond transient absorption and Kelvin probe force microscopy measurements further validate the existence of a built-in electric field in the vicinity of GBs, offering additional driving force for charge separation and establishing channels for swift carrier transport along the GBs, thereby expediting subsequent charge collection processes. This study elucidates the pivotal role of GBs in operational PSCs and provides valuable insights for the fabrication of high-efficiency PSCs.
Nano-Micro Letters•2025•DOI: 10.1007/s40820-025-01656-w
Sleep monitoring is an important part of health management because sleep quality is crucial for restoration of human health. However, current commercial products of polysomnography are cumbersome with connecting wires and state-of-the-art flexible sensors are still interferential for being attached to the body. Herein, we develop a flexible-integrated multimodal sensing patch based on hydrogel and its application in unconstraint sleep monitoring. The patch comprises a bottom hydrogel-based dual-mode pressure–temperature sensing layer and a top electrospun nanofiber-based non-contact detection layer as one integrated device. The hydrogel as core substrate exhibits strong toughness and water retention, and the multimodal sensing of temperature, pressure, and non-contact proximity is realized based on different sensing mechanisms with no crosstalk interference. The multimodal sensing function is verified in a simulated real-world scenario by a robotic hand grasping objects to validate its practicability. Multiple multimodal sensing patches integrated on different locations of a pillow are assembled for intelligent sleep monitoring. Versatile human–pillow interaction information as well as their evolution over time are acquired and analyzed by a one-dimensional convolutional neural network. Track of head movement and recognition of bad patterns that may lead to poor sleep are achieved, which provides a promising approach for sleep monitoring.
Int. Journal of Mining Science and Technology (采矿与安全工程)•2025•DOI: 10.1016/j.ijmst.2025.10.005
Weak structural planes commonly exist in underground engineering, making anchor structures more prone to failure and threatening rock stability. This study applied Optical-Thermal-Acoustic (OTA) monitoring during uniaxial compression tests on cross-layer anchored rock masses to reveal mechanical properties, failure characteristics, and energy evolution under different anchoring methods and bedding angles. Key findings include: anchoring suppresses transverse deformation and tensile crack propagation, increasing elastic modulus and bearing capacity; anchored rock shows more intense acoustic emission but smaller infrared temperature changes; the structural plane angle controls crack extension direction and strain evolution, with rock prone to instantaneous slip failure at 45°–75°, exhibiting lower strength and significant IR changes. Distinct OTA characteristics during rupture validate the method's reliability for rockburst early warning and intensity assessment. Based on failure characteristics, a shear failure criterion for anchored structural planes is established, enabling prediction of failure modes, analysis of bolt support resistance, and providing reference for support design and construction in complex strata.
China Foundry•2025•DOI: 10.1007/s41230-025-4184-0
Ceramic cores are key to forming a cooling structure within the hollow blade cavities. The use of stereolithography (SL) 3D printing technology eliminates the need for moulds, facilitating the preparation of complex-shaped ceramic cores. In this study, silica-based ceramic cores incorporating nano-3YSZ (3mol.% yttria stabilised zirconia) and micron-sized Y2O3 were prepared via SL 3D printing ceramic technology to promote the formation of cristobalite and ZrSiO4, thereby improving the high-temperature properties. The flexural strength at 25 °C and 1,500 °C, deflection at 1,500 °C, shrinkage rate, and porosity of the core samples sintered at different temperatures (1,170 °C, 1,185 °C, 1,200 °C, 1,215 °C, and 1,230 °C) were tested and investigated. The mechanism underlying the high temperature performance of the cores was elucidated through analysis of cross-sectional morphology, element distribution, and phase constitution of the samples. As the sintering temperature increases, the shrinkage and flexural strength at 25 °C of the core rise, while the open porosity and deflection at 1,500 °C decrease. When the sintering temperature reaches 1,200 °C or higher, the 1,500 °C flexural strength can be measured, which increases as the sintering temperature rises. The core exhibits excellent creep resistance when sintered at temperatures of 1,200 °C and above. Considering the comprehensive performance requirements for the core, the sintering temperature of 1,200 °C was selected. At the sintering temperature of 1,200 °C, the core exhibits shrinkage rates of 3.76% (X), 3.38% (Y), and 3.95% (Z), alongside a flexural strength of 9.01 MPa at 25 °C and 32.15 MPa at 1,500 °C, and an open porosity of 26.39%. The deflection of the core at 1,500 °C is 0.15 mm, which helps to maintain the dimensional stability of the ceramic core during casting. XRD results indicate that samples fractured after 25 °C flexural strength test still contain amorphous quartz glass, alongside substantial quantities of yttria stabilized zirconia and Y2O3. Samples fractured after 1,500 °C flexural strength test exhibit significant crystallisation of amorphous quartz glass into cristobalite, with silica and 3YSZ combining to form ZrSiO4. Y2O3 as a network modifier of the glass network destroys the bridging oxygen in the silica-oxygen bond, thereby reducing the energy required for glass crystallisation and promoting the crystallisation reaction of quartz glass to form cristobalite. In addition, nano-3YSZ combines with SiO2 at high temperatures to form ZrSiO4. Since cristobalite and ZrSiO4 are crystals, both of them have strong creep resistance, thus improving the high temperature flexural strength and deformation resistance of the ceramic cores.
Int. Journal of Minerals, Metallurgy and Materials (矿物冶金与材料学报)•2025•DOI: 10.1007/s12613-024-3058-6
In-situ TiB2/Al–Cu composite was processed by multidirectional forging (MDF) for six passes. The microstructure evolution of the forged workpiece was examined across various regions. The mechanical properties of the as-cast and MDFed composites were compared, and their strengthening mechanisms were analyzed. Results indicate that the grain refinement achieved through the MDF process is mainly due to the subdivision of the original grains through mechanical geometric fragmentation and the occurrence of dynamic recrystallization (DRX). DRX grains are formed through discontinuous DRX, continuous DRX, and recrystallization induced by particle-stimulated nucleation. A rise in accumulated equivalent strain results in finer α-Al grains and a more uniform distribution of TiB2 particles, which enhance the Vickers hardness of the composite. In addition, the tensile properties of the MDFed composite significantly improve compared with those of the as-cast composites, with ultimate tensile strength and yield strength increasing by 51.2% and 54%, respectively. This enhancement is primarily due to grain refinement strengthening and dislocation strengthening achieved by the MDF process.
Nano-Micro Letters•2025•DOI: 10.1007/s40820-024-01573-4
Global interest in lithium–sulfur batteries as one of the most promising energy storage technologies has been sparked by their low sulfur cathode cost, high gravimetric, volumetric energy densities, abundant resources, and environmental friendliness. However, their practical application is significantly impeded by several serious issues that arise at the cathode–electrolyte interface, such as interface structure degradation including the uneven deposition of Li2S, unstable cathode–electrolyte interphase (CEI) layer and intermediate polysulfide shuttle effect. Thus, an optimized cathode–electrolyte interface along with optimized electrodes is required for overall improvement. Herein, we comprehensively outline the challenges and corresponding strategies, including electrolyte optimization to create a dense CEI layer, regulating the Li2S deposition pattern, and inhibiting the shuttle effect with regard to the solid–liquid–solid pathway, the transformation from solid–liquid–solid to solid–solid pathway, and solid–solid pathway at the cathode–electrolyte interface. In order to spur more perceptive research and hasten the widespread use of lithium–sulfur batteries, viewpoints on designing a stable interface with a deep comprehension are also put forth.