Search Results (11,906)

In the context of increasing requirements for product quality and reduction in environmental impact, the improvement of aluminium alloy casting processes has become an important research area within Industry 4.0 and industrial digitalisation. The aim of this study was to develop a KPI-based model supporting the optimisation of high-pressure aluminium alloy casting processes, considering its influence on material properties and environmental performance. An important aspect of the proposed model is its adaptive potential and its implementation in real industrial conditions, which increases its application relevance in modern production systems. A set of key performance indicators describing process stability, quality, and resource efficiency was defined and linked to casting process parameters. KPI dashboards were developed to support the visualisation and analysis of key process parameters in relation to main and auxiliary processes. The analysis included microstructure evaluation and mechanical property assessment as a function of KPI values. The results confirm that the integration of KPIs within an Industry 4.0-oriented approach under conditions of industrial digitalisation supports effective optimisation of high-pressure aluminium alloy casting processes, leading to improved material quality and improved production sustainability. Full article

In geological carbon storage, cyclic casing loading can induce micro-annuli in the B-annulus cement sheath, risking CO₂ leakage. Compared with conventional cement, the Sn58Bi low-melting-point alloy boasts excellent flowability and favorable elastoplastic behavior, emerging as a promising sealing alternative. This study focuses on enhancing wellbore integrity by using Sn58Bi alloy to seal the B-annulus cement sheath. An experimental system was established to simulate micro-annulus evolution, with gas migration tests conducted under cyclic internal pressure to systematically evaluate the effects of temperature and cyclic loading on the alloy’s sealing performance. Additionally, a three-layer casing–annulus–formation coupling model was constructed to investigate the radial displacement of the Sn58Bi alloy sheath and cement sheath at 30 °C and 20 MPa casing pressure, clarifying their distinct mechanical responses. Results show that the alloy’s sealing performance improves with temperature (30–90 °C), while elevated cyclic internal pressure accelerates gas breakthrough and reduces sustainable cycles. Under identical conditions (30 °C, 20 MPa), Sn58Bi alloy exhibits significantly superior CO₂ sealing capacity to conventional cement. This study confirms the alloy’s potential for enhancing wellbore integrity and provides theoretical support for its application in B-annulus plugging during subsurface carbon storage. Full article

CoCrNiTiAl_x high-entropy alloy films with varied Al contents were fabricated on 42CrMo steel substrates via magnetron sputtering. By adjusting the sputtering power of the Al target, an investigation was systematically carried out to explore the effect of different Al contents on the microstructural evolution, mechanical properties, and corrosion resistance of the film, with the underlying synergistic mechanism governing these properties being elucidated. With increasing Al content, the film microstructure gradually transforms from an amorphous phase at low Al contents to a nanocrystalline–amorphous composite structure, until it is converted into the BCC phase, and the film’s crystallinity exhibits a trend of first increasing and then decreasing. In terms of mechanical properties, the film hardness is significantly enhanced from 7.6 ± 1.3 GPa to 18.9 ± 1.1 GPa with increasing Al content, while the toughness gradually declines. Wear tests show that the film wear rate first decreases and then increases with rising Al content, reaching a minimum of 2.06 × 10⁻⁵ mm³/N·m. The superior protective state, characterized by a corrosion potential reaching −361.2 mV and corrosion current density dropping to 1.12 μA/cm², arises from the generation of an integrated, consistently structured composite passivation barrier in 3.5 wt.% solution. This study confirms that appropriate Al doping can synergistically optimize the microstructure, mechanical properties, and corrosion resistance of CoCrNiTiAl_x films, providing experimental and theoretical support for the compositional design and engineering applications of high-performance high-entropy alloy protective films. Full article

The reliable joining of graphite and Cu holds significant promise for applications in electronic heat dissipation and sliding electrical contacts. However, the substantial differences in their physicochemical properties, poor wettability, and mismatch in coefficients of thermal expansion often result in low joint strength. In this study, a two-step joining strategy combines surface modification with low-temperature sintering, and this is proposed for fabrication of Cu/graphite joints. First, the graphite surface is modified using an AgCuTi active filler alloy under vacuum conditions. Ti preferentially segregates at and reacts with the graphite interface, leading to the formation of an Ag-Cu eutectic modified layer on the graphite surface. Subsequently, low-temperature joining of the modified graphite to a Cu substrate is achieved via a hot-pressing sintering process using a Ag paste. In the sintered joint, the Ag sintered layer forms sound metallurgical bonds with both the Cu substrate and the graphite-modified layer. When the sintering temperature is 250 °C, the joint exhibits a shear strength of 30 MPa, which is significantly higher than that of a directly brazed joint. This strategy effectively reduces thermal residual stress in the joint during cooling and shifts the failure location from the brittle graphite substrate to the ductile Ag sintered layer, thereby substantially enhancing the mechanical performance. Full article

Ultrathin titanium alloy foils are attractive for engineering components requiring flexural compliance and mechanical support, yet their recoverable deformation behavior at the foil scale remains insufficiently characterized. This study evaluates 30 μm Ti–24Nb–4Zr–8Sn (wt.%, Ti2448) foils in the as-rolled and solution-treated states and compares their tensile loading–unloading response with same-thickness CP Ti and Ti–6Al–4V reference foils. The Ti2448 foils exhibit a larger recoverable-deformation window and a lower apparent loading modulus than the reference foils under the same testing protocol. The highest recoverable strain is obtained in the solution-treated longitudinal condition, indicating that the recoverable deformation is sensitive to both processing state and loading direction. These results suggest Ti2448 foils as potential candidates for flexure-related applications requiring large recoverable deformation. Full article

Sodium (Na) metal anodes suffer from poor processability, severe volume fluctuation, unstable interfacial chemistry, and uncontrolled dendrite growth during cycling, which significantly hinder their practical application. Herein, a Na/Na₂In composite foil is fabricated through an in situ spontaneous alloying reaction enabled by a simple rolling–folding process using Na and indium (In) foils as precursors. Structural characterizations confirm the complete conversion of metallic In into the Na₂In alloy phase, forming a continuous architecture with uniformly distributed Na₂In networks embedded within the Na matrix. Owing to the sodiophilic and mechanically robust Na₂In framework, the Na/Na₂In composite anode effectively regulates Na plating/stripping behavior and suppresses dendritic growth, thereby maintaining a dense and stable electrode morphology during repeated charge/discharge processes. As a result, the Na/Na₂In symmetric cell exhibits stable cycling for over 900 h at 0.5 mA cm⁻² and 1 mAh cm⁻² with low polarization hysteresis, whereas the pure Na counterpart fails after only 143 h. Moreover, full cells paired with NaFe_1/3Ni_1/3Mn_1/3O₂ cathodes deliver enhanced cycling stability, retaining 87% of the initial capacity after 100 cycles at 0.5 C, together with improved rate capability. This work demonstrates a scalable mechanical fabrication strategy for high-stability Na metal composite anodes and provides new insights into the practical development of high-energy-density Na metal batteries. Full article

Cast Al-3Cu-Li alloys are limited by coarse grains and non-uniform Cu-rich phases, but their traverse-speed-dependent response to friction stir processing (FSP) has not been systematically clarified. The effect of FSP traverse speed on the microstructural evolution and mechanical properties of an Al-3Cu-Li alloy was systematically investigated. The alloy was processed at traverse speeds of 20 mm/min and 100 mm/min, and the resulting microstructures were characterized by XRD, SEM, EDS, EBSD and TEM. The results show that FSP does not significantly change the main phase constitution of the alloy, which remains dominated by the α-Al matrix with Al-Cu-related secondary phases. However, FSP markedly modifies the grain structure and precipitate distribution. Compared with the as-cast alloy, both FSP-treated samples exhibit refined equiaxed grains formed through dynamic recrystallization. The FSP-20 sample shows a finer and more homogeneous recrystallized structure, with a mean grain size of 4.60 ± 0.62 μm based on 982 measured grains, whereas the FSP-100 sample exhibits a coarser grain structure with a mean grain size of 15.20 ± 2.17 μm based on 109 measured grains. EBSD analysis further reveals that the FSP-20 sample possesses lower grain orientation spread and more dispersed local misorientation, indicating more sufficient dynamic recrystallization and lower residual deformation. TEM observations confirm the presence of plate-like T₁ precipitates in both FSP samples, while the precipitates in the FSP-100 sample are relatively coarser. Mechanical testing showed that the microhardness, yield strength, ultimate tensile strength and elongation increased from 62.4 HV, 92.8 MPa, 178.5 MPa and 10.86% in the as-cast alloy to 85.5 HV, 170.0 MPa, 228.9 MPa and 20.41% in FSP-20, and to 78.2 HV, 166.8 MPa, 202.9 MPa and 17.63% in FSP-100, respectively. Fracture analysis indicates that FSP-20 is dominated by ductile dimpled fracture, whereas FSP-100 shows more obvious quasi-cleavage features associated with coarse precipitates. Full article

This study systematically investigated the effects of Co/Ni ratios (0.6–2.0) on the solidification behavior, as-cast microstructure, and element segregation of Co-Al-W-based superalloys, and elucidated the mechanism of thermodynamic and kinetic synergistic regulation. The results show that increasing the Co/Ni ratio has a negligible effect on the liquidus and solidus temperatures, but it significantly lowers the dissolution temperature of the γ′ phase, thereby expanding the alloy’s heat treatment window (HTW) from 215 °C to 269 °C. As the Co/Ni ratio increased from 0.6 to 2, the SDAS at the center of the alloy ingot decreased from 112.4 μm to 43.3 μm, resulting in a significant refinement of the as-cast microstructure. The dendritic segregation coefficients for positively segregating elements such as Ta, Hf, and Al, as well as negatively segregating elements such as W, all approached 1 significantly, effectively suppressing microsegregation during solidification. This study reveals the multidimensional synergistic regulation mechanism of the Co/Ni ratio on the non-equilibrium solidification behavior of highly alloyed Co-Al-W-based superalloys and quantitatively elucidates the relationship between the Co/Ni ratio, the microstructural uniformity of as-cast specimens, and the heat treatment process window. For the first time in a highly alloyed multi-component Co-Al-W system, a correlation has been established between the Co/Ni ratio, element segregation, dendrite coarsening coefficient, and heat treatment window. Full article

xAl₃Zr/Al-5Cu-0.6Mn-0.15Ti composites were fabricated via an in situ reaction method, and the influence of Al₃Zr content on the microstructure and mechanical properties in both as-cast and T6-treated conditions was systematically investigated. The results reveal that the D0₂₃-Al₃Zr content increases in proportion to the K₂ZrF₆ addition level. Following T6 heat treatment, finely dispersed θ′-Al₂Cu precipitates were formed within the matrix, and the α-Al + θ-Al₂Cu eutectic network dissolved. The blocky Al₃Zr particles underwent spheroidization and could continuously exert a grain boundary pinning effect to suppress grain coarsening. After T6 heat treatment, the 4.5 wt.% Al₃Zr composite exhibited average ultimate tensile strengths of 324.44 MPa at room temperature and 123.38 MPa at 350 °C, corresponding to improvements of 8.56% and 23.31%, respectively, relative to the unreinforced base alloy. Following thermal exposure at 350 °C for 24 h, the composite exhibited less pronounced coarsening of the θ′-Al₂Cu precipitates compared with the base alloy, while the Al₃Zr particles retained their morphological and dimensional stability. Consequently, the reductions in both tensile strength and hardness were smaller than those observed for the base alloy. Analysis indicates that Al₃Zr particles significantly refine the α-Al grains and enhance the alloy’s thermal stability. The superior property retention is attributed primarily to the high thermal stability of the Al₃Zr particles, which preserve their dispersion-strengthening contribution at 350 °C, with the reduced θ′ coarsening as a contributing factor. The overall strengthening of the composite arises from the combined and largely independent contributions of Al₃Zr particle strengthening and θ′-Al₂Cu precipitation strengthening. Full article

This work systematically investigates the effects of pre-deformation, post-aging temperature, and aging time on the mechanical properties, corrosion behavior, and microstructure of a 2A97 Al-Cu-Li alloy. Microstructural characterization indicates that the main precipitates are T₁ (Al₂CuLi), δ′ (Al₃Li), θ′ (Al₂Cu), and S′ (Al₂CuMg). At 160 °C with 0% pre-deformation strain, increasing aging time increases the size and number density of T₁, changing the size and number density of δ′ and θ′ accordingly, whereas raising the aging temperature to 180 °C mainly coarsens precipitates. Increasing pre-deformation from 0% to 12% increases T₁ number density and refines its size. Significantly, after aging at 180 °C, θ′ is absent in the 8% and 12% pre-deformed alloys, and T₁ re-dissolves in the over-aged 12% alloy. Grain-boundary (GB) phases evolve from fine/discontinuous (under-aged) to fine/continuous (peak-aged) to coarse/discontinuous (over-aged). At the same time, higher pre-strain reduces their size, and higher aging temperature promotes coarsening. Higher aging temperature and pre-deformation accelerate age hardening and shorten the peak-aging time. In the peak-aged state, strength increases but elongation decreases with increasing pre-deformation or aging temperature. Among all, the 4% pre-deformed alloy aged at 160 °C for 30 h shows optimal room-temperature properties, i.e., ultimate tensile strength ~613 MPa, yield strength ~564 MPa, and total elongation ~6.91%. Corrosion resistance was closely related to microstructural evolution during aging, and both prolonged aging and increased pre-deformation decreased the susceptibility to intergranular corrosion. The results provide a basis for optimizing the thermomechanical processing of 2A97 Al-Cu-Li alloys. Full article

The use of bulk heat treatments to improve the resistance of the material structures to cavitation erosion remains an effective approach due to the beneficial modifications induced in the microstructure and physical-mechanical properties. Depending on the intensity of cavitation loading, various heat treatment regimes can be applied. Among these, artificial aging treatments are particularly suitable for non-ferrous alloys, especially aluminum, zinc, and magnesium-based alloys. The current study investigates the effect of artificial aging heat treatment performed at 250 °C with holding times of 12 and 24 h on the biodegradable magnesium-based AM50 alloy. Cavitation tests were carried out using the method with a stationary specimen on a standard vibratory device according to ASTM G32-2016 requirements. The analysis of cavitation-eroded surfaces through macro- and microstructural images, together with the interpretation of characteristic erosion curves and specific parameters (cumulative mass loss, erosion speed and cavitation resistance), revealed both similarities and significant differences governed primarily by surface hardness and microstructural features. Comparison with the initial (semi-finished) state and with previous studies on artificial aging treatments performed at 200 °C for 12 and 24 h confirms the similarly beneficial effect of the 250 °C aging regime on the cavitation erosion resistance of the AM50 alloy. Full article

Gallium (Ga)-based liquid metal (LM) composites, particularly those based on eutectic gallium–indium (EGaIn) and related alloys, have emerged as a promising materials platform for soft and deformable energy storage owing to their unique combination of metallic conductivity, fluidic deformability, and adaptive interfaces. Despite rapid advances in LM-enabled devices, binders remain insufficiently understood and are still commonly regarded as passive structural components. Here, we present a comprehensive binder-centered perspective for LM composites, establishing the binder as a key regulator of electro-chemo-mechanical coupling, interfacial stability, transport behavior, and processability in soft energy systems. We show that tailored binder chemistries in Ga-based LM systems—including stretchable batteries, printable conductors, and soft electrochemical devices—govern LM droplet dispersion, suppress coalescence and leakage, and preserve conductive percolation under large deformation, while enabling room-temperature fabrication and printability through rheological regulation and interfacial wetting. Beyond mechanical confinement, emerging binder functionalities—including dynamic bonding, supramolecular interactions, ionically conductive networks, and reversible polymer architectures—enable self-healing interfaces, adaptive transport pathways, and robust adhesion in deformable devices. By integrating recent advances in stretchable batteries, flexible supercapacitors, printable electronics, and multifunctional soft energy systems, we establish a unified multiscale framework linking binder molecular design to device-level electrochemical and mechanical performance. We further discuss sustainability and manufacturing considerations, including recyclable polymer networks, low-temperature fabrication, and scalable processing strategies. Finally, we outline current challenges and future opportunities toward programmable binder systems with tunable viscoelasticity, interfacial reactivity, and adaptive functionality. This Review establishes binder-centered engineering as a key pathway for transforming LM composites from proof-of-concept materials into resilient, manufacturable, and multifunctional soft energy technologies for wearable, stretchable, and biointegrated electronics. Full article

High-temperature corrosion severely impairs the service life of boiler heating tubes and threatens the safe and economical operation of thermal power units. With diversified fuels (coal, biomass and refuse-derived fuels) and continuously elevated operating parameters (steam temperature exceeding 620 °C for ultra-supercritical units), boiler heating surfaces are exposed to increasingly complex corrosive environments. High-temperature oxidation, sulfidation, chlorination, molten salt hot corrosion and deposit-induced multi-factor coupled corrosion coexist and exacerbate each other. This paper adopts a four-dimensional analytical framework of “mechanisms–technologies–materials–evaluation” to systematically summarize relevant research progress. From the perspective of corrosion mechanisms, the evolution of understandings from single high-temperature oxidation to multi-factor coupled corrosion is reviewed. In terms of surface coating technologies, seven mainstream processes including HVOF/HVAF spraying, plasma spraying, cold spraying, laser cladding and weld overlay are compared in terms of preparation characteristics and engineering applicability. For coating materials, twelve material systems such as NiCr alloys, MCrAlY, cermets, Fe-based amorphous/nanocrystalline alloys and high-entropy alloys are evaluated for their corrosion resistance under diverse service conditions. As for monitoring and evaluation, this work introduces full-range corrosion management technologies covering electrochemical monitoring, non-destructive testing, numerical simulation and life assessment. Finally, the paper discusses the application prospects of gradient coating design, AI-assisted material screening and digital twin technology, and points out key research gaps including long-term service reliability verification of coatings and quantitative prediction models for multi-factor coupled corrosion. Full article

To overcome the insufficient hardness and wear resistance of CoCrFeNi alloy coatings under heavy-load conditions, CoCrFeNi-TiC composite coatings with varying TiC mass fractions were fabricated on a 42CrMo substrate using laser cladding. The present study systematically investigates the effects of TiC content on phase composition, microstructural evolution, microhardness, and tribological behavior. The results show that TiC addition does not change the primary phase constitution of the face-centered cubic (FCC) matrix, but induces lattice distortion and grain refinement, resulting in a pronounced enhancement of coating hardness. As the TiC content increased, the average microhardness rose from 222.9 HV_0.2 to 380.9 HV_0.2, which was 1.7 times that of the coating without TiC. The enhanced hardness is mainly attributed to grain refinement, solid-solution strengthening, and the dispersion effects of TiC particles. The tribological performance showed a non-monotonic dependence on TiC content. Among the tested samples, the coating with 10 wt.%TiC showed the best wear resistance, with an average friction coefficient of 0.56 and a wear rate of 1.15 × 10⁻⁴ mm³/(N·m). However, further increasing the TiC content to 15 wt.% slightly reduced wear resistance because particle spalling promoted three-body abrasive wear. These results indicate that an appropriate TiC content can improve the balance between hard-phase strengthening and wear stability of CoCrFeNi-based composite coatings. This work clarifies the microstructure regulation and wear failure mechanism of TiC-reinforced coatings, providing experimental guidance for heavy-load service coating design. Full article

Aerospace load-bearing components require materials that exhibit high specific strength, excellent fatigue resistance, and superior environmental adaptability. Titanium alloys are indispensable for aerospace applications because of their exceptional mechanical properties, particularly their outstanding high specific strength, and their peak mechanical strength is typically achieved through solution heat treatment followed by artificial aging. This review systematically summarizes recent advances in the compositional design, microstructural evolution, and critical microstructure–property relationships of aerospace titanium alloys. It further highlights intrinsic effects of alloying elements on phase stability, dislocation behavior, and phase transformation pathways, and analyzes how lamellar, equiaxed, and bimodal microstructures regulate dislocation transfer, local strain partitioning, and damage evolution. The interactions and competition among deformation and phase-transformation mechanisms, including slip anisotropy, deformation twinning, stress-induced phase transformations, and ω-related processes, are critically assessed. However, unresolved challenges remain in quantitatively characterizing multi-mechanism coupling and local heterogeneity. To address these challenges, this review elucidates the transition rules of dominant mechanisms across different microstructures and proposes a high-precision digital composition–microstructure–property mapping framework to facilitate predictive and service-oriented alloy design. Full article