Search Results (12,361)

CoNiV medium-entropy alloy (MEA) composite coatings reinforced with 40 wt.% tungsten carbide (WC/W₂C) particles were fabricated on carbon steel via laser cladding under nominal heat inputs ranging from 75 to 150 J/mm. The phase constituents and microstructural evolution were investigated, revealing that the coatings were primarily composed of an FCC matrix, retained WC/W₂C particles, and in situ formed V-rich and VWC₂ carbides. While the phase compositions remained generally consistent, the features of the reinforcement architecture varied with the extent of WC/W₂C dissolution governed by laser heat inputs. At low heat inputs, limited particle dissolution yielded sparsely distributed in situ carbides, whereas excessive dissolution at high heat inputs promoted the agglomeration of dense and coarse carbides, driving the microhardness to peak at 570.5 HV_0.5. However, the coating deposited at 150 J/mm exhibited compromised wear resistance due to the fragmentation and detachment of these coarse carbides, which intensified abrasive wear. In contrast, moderate dissolution at intermediate heat input (100 J/mm) facilitated the formation of fine in situ carbides in interparticle regions. This resulted in a homogeneous multiscale synergistic reinforcement microstructure that endowed the coating with optimal wear performance. By precisely controlling heat input to regulate in-situ precipitation, this study established a solid foundation for tailoring wear resistance and expanding the application of composite coatings. Full article

Molten salt electrodeposition is a promising technique to prepare high-performance tungsten coatings for fusion reactor first-wall components. However, the ultra-high temperature during deposition causes severe grain coarsening and precipitate dissolution in CuCrZr alloy substrates, resulting in dramatic mechanical property degradation. In this study, a thermal cycle at 1223.15 K for 100 h was employed to simulate the thermal impact of molten salt tungsten electrodeposition (MSE) on CuCrZr alloys, and an aging treatment (703.15 K for 12 h) was adopted to restore the degraded mechanical properties. After aging, the tensile strength and yield strength recovered to 378.35 ± 7.40 MPa and 261.02 ± 3.40 MPa, meeting the minimum tensile property requirements of ITER for CuCrZr alloys. The recovery is attributed to nano-sized Cr-rich phase precipitation and high-density dislocations, providing effective Orowan precipitation strengthening. This work provides the first simple, engineering-friendly post-treatment to repair performance degradation of CuCrZr under the extreme thermal exposure of molten salt electrodeposition, which is critical for large-scale fabrication of high-performance plasma-facing components (PFCs) for fusion reactors. Full article

The integration of Selective Laser Melting (SLM) into high-end manufacturing necessitates robust machine-condition monitoring and subsystem fault classification to navigate the intricate coupling and dynamic transients inherent in these systems. Current diagnostic frameworks often struggle to decouple high-dimensional state variables or track their underlying temporal evolution. To overcome these bottlenecks, this paper develops a spatiotemporal deep learning architecture by coupling Convolutional Neural Networks (CNNs) with Long Short-Term Memory (LSTM) units. This hybrid approach leverages CNNs to distill multi-dimensional spatial features from subsystem sensor arrays, while LSTMs interpret the sequential dependencies critical for identifying systemic drifts. The proposed framework was validated using an extensive industrial dataset comprising over 310,000 temporal samples across seven critical SLM subsystems, including optical, cooling, and energy units. We systematically investigated three data-handling strategies—feature weighting, balancing, and distribution-based synthesis—to optimize the model’s sensitivity to rare-event anomalies. Benchmarking across six architectural variants reveals that a specific CNN × 3 + LSTM × 1 configuration yields superior diagnostic fidelity, achieving a classification accuracy of 98.81%. Visualization of the feature space confirms high inter-class separability, demonstrating the model’s ability to isolate faults within complex manufacturing cycles. This research offers a scalable paradigm for the intelligent monitoring of SLM equipment and provides a technical benchmark for equipment health management and predictive maintenance in advanced additive manufacturing. Full article

Variable cross-section cement–soil pipe piles are an innovative soft ground improvement technology. They are tubular, special-shaped cement–soil mixing piles characterized by a tapered profile along the pile shaft (larger diameter at the top and smaller at the bottom) and an internal soil core. They offer advantages including reduced material consumption, lower engineering cost, and shorter construction duration. However, the systematic theoretical understanding of their bearing performance remains insufficient. In this study, the bearing mechanism and influencing parameters of variable cross-section pipe piles were systematically investigated via full-scale field tests, numerical simulations, and laboratory model tests. An exponential decay constitutive model considering the strain-softening behavior of cement–soil was developed and implemented through secondary development in the ABAQUS platform for parametric analysis. Laboratory model tests were further conducted to advance the understanding of the bearing mechanism of variable cross-section pipe piles. The results show that the ultimate bearing capacity of the proposed variable cross-section cement–soil pipe pile is approximately 189% higher than that of the conventional ones. The expanded outer diameter and expanded height are the dominant factors affecting the bearing capacity, while the inner diameter and pile length have a comparatively minimal influence: increasing the expanded outer diameter from 0.6 m to 1.2 m and the expanded height from 0 m to 5 m increased the ultimate bearing capacity from 445 kN to 868 kN and 936 kN, respectively. The effective pile length is determined to be 6 m, and the recommended minimum wall thickness of the pipe pile is 1/4 of the inner diameter. Laboratory tests further demonstrated an abrupt change in axial force at the variable section. The findings provide reliable theoretical support for the engineering design and field application of cement–soil variable cross-section pipe piles. Full article

This study investigates the feasibility of utilising alkali-activated slag (AAS) and construction demolition waste (CDW) as cemented paste backfill materials. The fluidity, unconfined compressive strength, bleeding rate, and sulfate resistance of AAS-CDW backfill systems were systematically analysed. Hydration mechanisms were characterised using SEM-EDS and XRD. A novel backfill system and application process were developed and implemented in Jining Coal Mine, Shandong Province. Results indicate that a 30% waste red brick addition enhances 28-day compressive strength by 9.3% and reduces the bleeding rate by 32%, while a 10% fly ash addition optimises slurry fluidity. Notably, the AAS-based backfill exhibits superior mechanical properties and sulfate resistance compared to ordinary Portland cement (OPC)-based systems. The 28-day compressive strength of the AAS backfill reached 5.31 MPa, which is 53.4% higher than that of the OPC backfill, and its strength loss rate after sulfate attack was reduced by 13%. The solid waste utilisation rate of the AAS backfill approaches 100%. Hydration products primarily comprise ettringite (Aft), C-A-S-H gel, and hydrotalcite (HT), resulting in higher compactness than OPC-RA mixtures. Full article

Road pavement rehabilitation increasingly incorporates innovative surface technologies aimed at improving pavement performance while reducing environmental impacts. In addition to conventional recycled asphalt pavement (RAP) maintenance strategies, advanced pavement surface systems such as reflective coatings, rejuvenator-based self-healing mixtures, and thin low-noise asphalt layers have been developed to enhance durability and functional performance. This study presents a comparative Life Cycle Assessment (LCA) of four pavement surface technologies using primary inventory data obtained from full-scale road sections. The systems evaluated include a conventional maintenance mixture and three alternative surface solutions: reflective pavement coatings, RAP mixtures incorporating rejuvenator-based self-healing systems, and thin low-noise asphalt layers. The assessment follows ISO 14040 and ISO 14044 standards and applies the ILCD 2011 midpoint+ (EF 2.0) method. To enable comparability between technologies with different durability, the functional unit was defined as 1 m² of rehabilitated pavement per year of service life. The results indicate that thin low-noise asphalt layers provide the highest environmental benefits across most impact categories due to significant material savings associated with reduced layer thickness. Reflective pavement coatings decrease several impacts, particularly fossil resource depletion and atmospheric emissions, although higher burdens are observed in some categories due to synthetic binder production. RAP mixtures incorporating rejuvenator-based self-healing systems improve resource efficiency and extend pavement durability but may increase impacts associated with binder manufacturing. Overall, the findings highlight relevant environmental trade-offs between different pavement surface technologies and demonstrate that parameters such as layer thickness, binder composition, recycled material content, and service life strongly influence environmental performance. The study illustrates how comparative Life Cycle Assessment supports the development and selection of more sustainable pavement surface systems. Full article

An equiatomic FeCoCrNiMn high-entropy alloy was processed by cold rolling followed by isothermal annealing at 900 °C for various durations. The microstructural evolution and mechanical properties of the alloy were systematically investigated as a function of annealing time. The results indicate that the alloy maintained a single-phase face-centered cubic (FCC) structure throughout the entire annealing process, with no secondary phases or precipitates detected. After annealing at 900 °C for 2 min, the recrystallized volume fraction reached approximately 80%, resulting in the formation of an ultrafine-grained microstructure. The corresponding Vickers hardness, yield strength, and total elongation were measured to be 249 HV, 616 MPa, and 32%, respectively, demonstrating a desirable combination of strength and ductility. The recrystallization process was essentially complete after 5 min of annealing. With further increases in annealing time, the grain size continued to coarsen, accompanied by a gradual decrease in hardness and strength and a progressive improvement in ductility, reflecting a typical strength–ductility trade-off. Full article

The Xi’an Beilin Museum preserves a large collection of archeological photographic negatives and films dating from the 1950s to the early 1980s. These images document significant archeological discoveries, including Tang dynasty imperial tomb murals, the excavation of the terracotta warriors, and various historical grottoes and stone carvings. As unique visual records of cultural heritage, these materials provide valuable references for studying environmental deterioration processes and for guiding conservation and restoration practices. However, long-term storage under uncontrolled environmental conditions has resulted in severe degradation of the negatives, including mold contamination, emulsion layer powdering, deformation, and partial detachment. Among these deterioration phenomena, microbial growth is particularly destructive because fungal hyphae cause light scattering and image obscuration, preventing scanning and digital archiving. In this study, mold species present on the negatives were isolated and identified using morphological observation and ITS rDNA sequence analysis. Based on the characteristics of the microbial contamination, targeted removal and restoration treatments were applied to recover the original image information. Furthermore, preventive protection strategies were implemented through the development of antifungal storage materials and protective containers. The results establish an integrated conservation approach combining microbial identification, restoration treatment, risk elimination, and preventive protection, providing a scientific basis for the long-term preservation of historical photographic archives. Full article

Silicon-doped diamond-like carbon (Si-DLC) coatings against aluminum alloy (A5052) were investigated for reducing friction under humid conditions. The coatings were deposited on high-speed steel (SKH51) substrates using a bipolar-type plasma-based ion implantation and deposition (PBII&D) technique, with Si content controlled by varying the tetramethylsilane (TMS)-to-toluene precursor ratio. Structural characterization by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) confirmed the progressive evolution of Si–C bonding with increasing TMS ratio. The Si-DLC coating with Si 5.0 at.% exhibited the lowest coefficient of friction (COF) of 0.033 and reduced wear volume under a high normal load of 150 N in humid conditions (relative humidity > 90%). However, Si-DLC coatings with higher Si contents (Si 7.7 and 14.3 at.%) led to deteriorated tribological performance, including coating delamination and severe wear. Surface analyses of the coatings revealed that the low-friction behavior was associated with the presence of oxidized Si species at the outermost surface, which undergo hydroxylation in humid environments to form Si–OH groups. These hydroxylated surfaces promote the formation of a hydrated boundary layer that provides a low-shear sliding interface. Full article

Cr–N coatings are promising for severe-service applications owing to their high corrosion and wear resistance, yet their performance is governed by phase constitution and multilayer architecture. In this study, a monolithic Cr coating and three Cr-based multilayer coatings, Cr/Cr(N), Cr/Cr₂N, and Cr/CrN, were synthesized by a hybrid DCMS/HiPIMS process and systematically compared with respect to structure, mechanical properties, and oxidation behavior at 900 °C. XRD and TEM showed that Cr/Cr(N) was primarily characterized by a bcc Cr-type structure, while the N-containing layers exhibited slightly expanded lattice spacings relative to pure Cr; no Cr₂N precipitates were detected within the resolution of the analyses. Among the multilayers, Cr/Cr(N) provided the most favorable combination of hardness, adhesion, and indentation damage tolerance, reaching 885 HV and a critical scratch load of 80 N while maintaining damage tolerance comparable to monolithic Cr. By contrast, Cr/Cr₂N and Cr/CrN displayed more pronounced brittle damage and lower interfacial reliability. Upon oxidation at 900 °C, Cr and Cr/Cr(N) formed relatively compact Cr₂O₃ scales, whereas Cr/Cr₂N, and particularly Cr/CrN, experienced stronger oxidation-induced phase decomposition, blistering, and local delamination. These findings identify Cr(N) solid-solution sublayers as an effective alternative to brittle ceramic nitride layers. Full article

In this paper, we utilized sodium titanate as a substrate to fabricate a supported antifungal repair agent capable of inhibiting fungi through the release of silver ions, and applied it to the preservation and restoration of wooden materials. The structural and material properties of sodium titanate were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), and adsorption kinetic modeling. Furthermore, its effectiveness in wood restoration as well as its antifungal performance were evaluated. Results indicate that the synthesized sodium titanate exhibits a distinctive tubular structure, with a diameter of approximately 12 nm, a pore size of 7 nm, and a specific surface area as high as 310.91 m²/g. The abundant ion exchange active sites on the material surface provide conditions for the loading of silver ions. At 25 °C, the maximum adsorption capacity for silver ions reaches 515.5 mg/g, with an adsorption amount accounting for 34.0 wt.%. When combined with polyvinyl alcohol (PVA) for reinforcing wooden materials, it significantly increases the packing density of the reinforcing agent, ultimately enhancing the compressive strength of wood from 155.0 MPa to 412.2 MPa. Furthermore, owing to the antifungal effect of silver ions, the treated wood demonstrates effective resistance against the growth of Aspergillus niger. Full article

In this review, the application of microbially induced calcium carbonate precipitation (MICP) for repairing coal mining-induced cracks in loess soils was summarized, and its objectives, main findings, and key challenges were highlighted. First, the formation characteristics and engineering demands of mining-induced loess cracks were analyzed, and the limitations of existing repair methods in terms of durability, adaptability, and environmental impact were emphasized. The advantages of MICP for soil stabilization, crack sealing, and ground improvement were presented, demonstrating its potential for use in the remediation of cracks in loess. Key challenges in practical implementation, including uneven injection, clogging, environmental constraints on microbial activity, ammonia byproduct risks, and insufficient long-term stability assessment, were discussed. Overall, MICP offers a sustainable and effective strategy for loess crack repair, providing a promising approach for ecological restoration and geotechnical reinforcement in mining-affected regions. Full article

In this review, a comprehensive analysis of aluminide coatings for nickel-based superalloys was performed with the particular emphasis on their processing, microstructural evolution, and performance under high-temperature conditions. Nickel-based superalloys are widely used in power engineering and aerospace industries; however, their susceptibility to oxidation and hot corrosion necessitates advanced surface protection strategies. Aluminide coatings offer effective protection through the formation of stable and adherent alumina scales. The review systematically evaluates major deposition techniques, including chemical vapour deposition (CVD), pack cementation, slurry aluminizing, and advanced hybrid methods, highlighting their influence on coating structure and properties. Special attention is given to the relationship between processing parameters, microstructure, and functional performance, including oxidation resistance, corrosion behaviour, and mechanical properties such as hardness and fatigue life. Full article

To address the application requirements of energy storage devices for new energy electric vehicles—including high energy density, high-power density, fast charging and discharging, and long-term cycling stability—traditional symmetric supercapacitors are often limited by low energy density and poor compatibility between the anode and cathode, making it difficult to meet the high-efficiency energy storage demands under the dynamic operating conditions of electric vehicles. This study focuses on the regulation of hierarchical thin-film structures and the innovative heterogeneous coating interface engineering with precise slurry coating and film-forming optimization and designs and fabricates NiCo₂O₄/NiFeO composite thin-film electrodes and Mn-doped porous carbon (Mn-PC) thin-film electrodes. The uniform, compact and stable coating formation on nickel foam substrates via controllable slurry coating facilitates the efficient integration of active materials and conductive supports. The electrode slurries were coated onto conductive nickel foam substrates, and high-performance aqueous supercapacitors were assembled using an asymmetric configuration. A systematic study was conducted covering material preparation, structural characterization, electrochemical testing, and full-device performance evaluation. Using techniques such as XRD, XPS, SEM, TEM, BET, and an electrochemical workstation, the study revealed the structure–activity relationships among material morphology, crystalline phases, pore structure, and electrochemical performance, elucidating the charge storage mechanisms of the composite electrode films and the principles of synergistic adaptation between the anode and cathode. The results indicate that NiCo₂O₄ nanowires decorated with in situ-grown NiFeO nanosheets to form a composite structure; when coated onto nickel foam, this forms a uniform, porous electrode film with a specific surface area of 171.3 m²/g, a specific capacitance as high as 1746 F/g at 1 A/g, and a capacity retention rate of 94.0% after 10,000 cycles. After coating and film formation, the Mn-PC anode introduced pseudocapacitive active sites through uniform Mn doping, resulting in a film electrode specific capacitance of 348 F/g and significantly improved rate and cycling performance. The assembled NiCo₂O₄/NiFeO//Mn-PC asymmetric supercapacitor exhibits a thin-film electrode specific capacitance of 153 F/g at 1 A/g, with a maximum energy density of 52 Wh/kg. Even at a power density of 9000 W/kg, it maintains 45 Wh/kg, and retains 89.5% of its capacity after 10,000 cycles, with overall performance outperforming most previously reported transition metal-based devices. This coating-engineered electrode fabrication strategy breaks through the interface mismatch and structural instability bottlenecks of traditional thin-film electrodes, providing a novel material system and an efficient coating assembly strategy for high-performance supercapacitor thin-film electrodes in new energy electric vehicles, and offers experimental evidence and technical references for the development and application of high-power energy storage coating devices for automotive use, as well as the innovative design of electrode coating engineering in energy storage fields. Full article

Titanium dental implants are widely regarded as the gold standard for the rehabilitation of missing teeth due to their high survival rates and favorable mechanical properties. However, in the oral environment, implant materials are continuously exposed to complex chemical, mechanical, and biological factors that may lead to surface degradation, including corrosion, tribocorrosion, and mechanical wear. These processes can alter implant surface characteristics and influence biological responses in peri-implant tissues. Zirconia implants have been introduced as alternative material due to their favorable aesthetics and biocompatibility. Nevertheless, zirconia ceramics are also susceptible to degradation phenomena, including hydrothermal aging, phase transformation, and surface wear under specific conditions, although their clinical relevance remains unclear. In addition, emerging hybrid titanium–zirconia implant systems introduce new considerations regarding surface stability. This scoping review, conducted in accordance with PRISMA-ScR guidelines, summarizes the current evidence on degradation mechanisms affecting titanium, zirconia, and hybrid dental implants, with particular focus on processes occurring in the oral environment and their biological and clinical implications. The available evidence differs substantially between the two materials. While titanium degradation is well documented and supported by both experimental and clinical studies, the evidence for a hybrid implant remains limited and is largely based on in vitro and mechanistic data. Full article