The grain growth behavior of nickel-based superalloys is of great significance for the formulation of forging and heat treatment processes. The grain growth behavior of GH3230 alloy was studied in the temperature range of 1 150 ℃-1 240 ℃ for 1-10 hours. The effects of critical process parameters such as heating temperature and holding time， on the grain size were analyzed， and a grain growth model of GH3230 alloy was established. The results show that the grain growth of GH3230 alloy is more sensitive to the heating temperature. Grain growth accelerates rapidly with increasing temperature. When the heating temperature is higher than 1 220 ℃， abnormal grain growth occurs. The precipitation of carbides on the grain boundaries pinns the grain growth. After holding at 1 150 ℃ for 3 hours and at 1 180 ℃-1 240 ℃ for 1 hour， the original carbides on the grain boundaries gradually dissolve， and the grain growth rate increases. A grain growth model of GH3230 alloy in the heating range of 1 150 ℃-1 220 ℃ and holding time not exceeding 10 hours was established as D=D0+e12.66t0.206exp（-133 602/RT）， and the predicted values are in good agreement with the experimental values. The results can provide certain references for actual production and numerical simulation studies.

Cu-modified C/C-ZrC composites are promising for thermal protection due to combined passive and active ablation resistance. However, the influence of preform orientation on Cu and ceramic distribution and ablation behavior is unclear, especially for 2.5D needle-punched fiber preform. In this work, Cu-modified C/C-ZrC composites were fabricated via reactive melt infiltration by varying infiltration direction and Cu powder placement using 2.5D needled preforms. Under XY-direction infiltration, Cu showed a fluctuating distribution with obvious local enrichment. This behavior was related to the relatively high through-thickness infiltration resistance. In contrast, Z-direction infiltration favored directional Cu migration. When combined with bottom Cu powder placement, it further produced a relatively stable through-thickness Cu gradient. Under an oxy-acetylene heat flux of 4.2 MW/m2, the gradient-structured composite exhibited the lowest surface temperature and the lowest linear and mass ablation rates, while maintaining superior structural stability during both initial and cyclic ablation. Microstructural observations suggest that this improvement is related to a more stable oxide layer, reduced crack propagation, and better interfacial integrity between the oxide scale and substrate. Overall, preform orientation directly governs component distribution and ablation performance in Cu-modified C/C-ZrC composites, with the gradient structure offering enhanced thermal protection for extreme environments.

Conventional carbon/carbon-zirconium carbide (C/C-ZrC) composites, though promising for ultra-high-temperature applications, often struggle to balance active cooling and passive oxidation protection, as uncontrolled metal redistribution during service leads to structural instability and premature ablation failure. In this study, copper (Cu) gradient-modified C/C-ZrC composites were fabricated via reactive melt infiltration (RMI) using a layered powder-laying strategy with Cu powders of distinct morphologies to achieve programmable Cu distribution. Two opposite gradient architectures were designed: a Cu-decreasing (ZCI) and a Cu-increasing (ZCS) configuration along the infiltration direction. Microstructural and ablation analyses revealed that the Cu gradient markedly altered the infiltration-reaction pathway and ZrC grain evolution. In ZCS prepared with spherical Cu powders, a dissolution-recipitation mechanism generated fine spherical ZrC grains and a Cu-rich basal layer that sustained heat absorption and conduction, forming a dense bilayer ZrO2 structure that effectively suppressed oxygen diffusion. Benefiting from this architecture, the ZCS composite exhibited the lowest mass ablation rate of-0.39 mg/s under a 4.18 MW/m2 oxy-acetylene flame for 30 s, along with superior surface integrity and thermal stability. This work establishes a direct mechanistic link between Cu gradient architecture and ablation resistance, providing a controllable design paradigm for next-generation active-passive synergistic thermal protection systems.

Coarse columnar grains and high porosity are the primary issues restricting the widespread application of 2319 aluminum alloy components produced by wire arc additive manufacturing (WAAM). Regulating microstructural characteristics through external magnetic fields has emerged as one of the core research directions to enhance the performance of WAAM components. However, the underlying mechanisms through which different magnetic field configurations influence arc behavior and the microstructure of deposited layers remain unclear. To this end, this study innovatively employs a directionally controllable magnetic field device, systematically investigating the multi-scale regulatory mechanisms of transverse and longitudinal magnetic fields on arc morphology, molten pool behavior, columnar-to-equiaxed transition (CET), and porosity suppression. The results demonstrate that the application of magnetic fields improves the inhomogeneous temperature distribution during solidification by constricting and deflecting the arc and spreading the molten pool, thereby effectively facilitating the homogeneous distribution of solute elements and inhibiting the formation of coarse network-like eutectic phases. Notably, transverse and longitudinal magnetic fields exhibit distinct functional differentiation: the transverse magnetic field manifests remarkable efficacy in porosity suppression, reducing the volumetric porosity from 0.56 % (without a magnetic field) to 0.22 %. In contrast, the longitudinally dominant magnetic field focuses on grain refinement, efficiently breaking columnar grains to form a fully equiaxed grain structure, with the average grain size refined from 39.57 mu m to 22.70 mu m. Consequently, a targeted magnetic field regulation strategy is proposed: a transverse field is used to minimize porosity; a longitudinal field is employed to refine grains. Furthermore, the synergistic or sequential application of both fields can be explored to achieve optimal performance. Ultimately, this work provides a novel pathway for precise microstructural tailoring and quality enhancement in magnetic field-assisted WAAM of aluminum alloys.

Unloading-induced bone loss is a major medical challenge during long-duration human spaceflight, largely driven by suppressed osteoblast-mediated bone formation, and practical countermeasures are needed. Electromagnetic stimulation has shown benefits for bone repair, and its non-invasiveness supports potential space use; however, its single-modality efficacy remains limited. Here, we investigated a combined electromagnetic field (CEMF) integrating a static magnetic field (SMF, 0.4–0.6 T) and a pulsed electromagnetic field (PEMF, 0.38 ± 0.19 mT) to attenuate unloading-related bone loss and examine field-induced mechanical stimulation. Finite-element simulations mapped magnetic flux density, field gradient, induced current density, and Lorentz force density in bone tissue. CEMF was evaluated in vivo in hindlimb unloading (HLU) mice and in vitro in MC3T3-E1 osteoblasts. CEMF improved bone mineral density, trabecular and cortical microarchitecture, and mechanical properties in HLU mice, with increased osteoblast number and mineral apposition rate. In vitro, CEMF promoted osteogenic differentiation and upregulated COL1A1 and RUNX2. Transcriptome analysis suggested activation of ECM–integrin mechanical signaling and the PI3K–AKT pathway. These findings indicate that CEMF-induced multiphysics stimulation enhances osteogenic responses and may serve as a complementary, non-invasive countermeasure for spaceflight-associated bone loss.

Ceramics modified carbon/carbon (C/C) composites show great promise in thermal protection systems, yet achieving a balance between mechanical and anti-ablation properties in sharp leading-edge (SLE) C/C composites under ultrahigh-temperature conditions remains challenging. Herein, a bioinspired vacuum-driven, bottom-up reactive melt infiltration (RMI) technique was developed to fabricate SLE C/C-ZrC-ZrxCuy-Cu composites, which could not only mitigate tip erosion during fabrication, but also enable microstructure tailoring through localized vacuum control and fiber orientation. The fabricated composites, exhibiting low structural corrosion damage, featured a dense and highly cohesive ZrC-ZrxCuy-Cu matrix and efficient energy dissipation behavior under external loading, resulting in a high flexural strength (205.68 +/- 25.98 MPa) and elastic modulus (14.72 +/- 2.02 GPa). Impressively, the SLE C/C-ZrC-ZrxCuy-Cu composites with a gradient Cu/Zr atomic ratio along the infiltration direction demonstrated exceptional long-term thermal protection for 300 s under oxyacetylene flame ablation at similar to 2500 degrees C with good structural integrity, low mass (4.53 +/- 0.26 mg/s) and linear (2.89 +/- 0.35 mu m/s) ablation rates, significantly outperforming most reported SLE composites. The superior performance arose from active-passive thermal protective effects of Cu-induced "sweating-cooling" and "dynamic self-healing" of a Cu-Zr-O scale during ablation, together with defect-mediated dislocation-mediated strain redistribution and oxide-scale toughening during cooling. This study provides a general bioinspired strategy for synergistically enhancing flexural and ablation-resistant properties of thermal protection materials in severe thermal environments.

A critical challenge in developing microwave-infrared dual-band stealth technology lies in constructing multifunctional materials that achieve both broadband electromagnetic-wave absorption and efficient thermal insulation. Inspired by polar bear hair (hollow structure) for thermal insulation and Parotia wahnesi crown feathers (array structure) for light trapping, we engineered a bioinspired SiC hybrid aerogel comprising hollow microtubes and in situ grown nanowire arrays, thereby forming multiscale interfaces such as tube-nanowire junctions, nanowire-catalyst contacts, SiC core-SiO2 shell heterostructures, and 3C/2H SiC phase boundaries. Through the synergistic combination of the macroscopic hierarchical architecture and precise multiscale interface engineering, the SiC hybrid aerogels achieve exceptional multifunctional performance. By carefully regulating the thickness of the SiO2 shell via the oxidation temperature, optimal impedance matching and enhanced polarization loss are attained. The SiC aerogel oxidized at 1100 °C exhibits superior microwave absorption, with an effective absorption bandwidth of 5.525 GHz (12.475-18 GHz) at a thickness of only 1.65 mm and a minimum reflection loss of -51.75 dB at 1.45 mm. Simultaneously, the bioinspired multiscale porous architecture effectively suppresses heat conduction, endowing the SiC hybrid aerogel with excellent thermal insulation properties. This work demonstrates that integrating bioinspired structural design with multiscale interface engineering offers an effective strategy for developing high-performance, multifunctional materials with dual-band stealth and thermal protection.

The anti-/de-icing method employing Surface Dielectric Barrier Discharge (SDBD) plasma actuators have gained considerable attention for aircraft applications, owing to their compact structure, fast response, minimal weight, and ease of integration. Despite extensive research over the past decade, the physical mechanisms governing anti-/de-icing based on SDBD plasma actuators remain inadequately understood. In particular, the mutual interactions between impinging water droplets and the flow fields created by SDBD plasma actuators have not been fully explored. This work experimentally investigates the dynamic coupling between a single impacting droplet and a SDBD plasma actuator using infrared thermography and high-speed Particle Image Velocimetry (PIV). The evolution of droplet morphology and the induced flow field are discussed throughout the droplet impact process, including free fall, spreading, and recoiling stages. Based on the measured data, a predictive model is developed to estimate the maximum spreading ratio of droplets under plasma actuation within limited ranges of Reynolds and Weber numbers.

Inter-layer rolling integrated with wire arc additive manufacturing (WAAM) effectively improves inherent defects (poor interlayer bonding, high defect density, and inferior mechanical properties) in aluminum alloys by introducing severe plastic deformation. However, the alternating WAAM-rolling process faces bidirectional interdependencies: WAAM-deposited rib morphology influences rolling strain distribution, while rolled surface geometry alters subsequent WAAM energy distribution and material deposition. Morphology inheritance across passes critically determines the forming accuracy of high-rib structures. Unfortunately, existing models oversimplify this by assuming idealized geometries, leading to unreliable predictions. To this end, a high-precision numerical model for WAAM-rolling was developed here, incorporating true rib morphology from prior passes as initial conditions to achieve bidirectional morphology inheritance. An integrated multi-pass simulation framework was established to analyze rib evolution under various roller types and rolling reductions. Results demonstrate that lateral restraint rollers significantly improve rib accuracy (± 0.01 mm) and molten pool spreading. Both 50

Wire arc additive manufacturing (WAAM) enables the integral fabrication of aluminum alloy components with high ribs and thin webs. However, coarse grains, residual crystalline phases (RCPs), and porosity defects weaken mechanical properties and limit applications. Although interlayer plastic deformation during WAAM can improve the microstructure and porosity defect, it exhibits limitations in deformation degree and uniformity. To address this, this study proposes an asynchronous bidirectional rolling process integrated with heat treatment (surface rolling -> recrystallization annealing -> side rolling -> T6 ageing) to enhance the properties of WAAM 2319 aluminum alloy. Compared to conventional rolling, bidirectional rolling demonstrates superior microstructural uniformity and strength-plasticity balance. This superiority stems from the bidirectional rolling combined with intermediate annealing: it refines grains and reduces porosity while inducing alternating compressive-tensile strains within preferentially oriented RCPs. This effectively blunts brittle second-phase particles and accelerates their separation and migration. Consequently, it promotes the formation of longer and thinner theta(y) phases after solution-ageing treatment, thereby enhancing the precipitation strengthening effect. Furthermore, it significantly delays the formation of pore-induced matrix cracking (PIMC) and interfacial bonded voids (IDVs), which alleviates local stress concentrations and thus improves plasticity.

Strain path is a critical factor governing the forming quality of metallic components,includ-ing their geometry,microstructure,and service performance.Achieve high-quality forming often requires the use of nonlinear and complex strain paths,which inevitably give rise to multiscale deformation behav-iors.Understanding and characterizing these mechanisms has therefore become a frontier topic in the field of plastic forming.This review synthesizes recent advances in the investigation of macroscopic me-chanical responses,damage behavior,and microstructural and textural evolutions under complex strain paths,emphasizing the central role of stress path history in shaping multiscale deformation mechanisms.Finite element modeling strategies that account for strain path effects are discussed,including constitutive models,limit prediction and damage models,as well as microstructure evolution models,with particular at-tention to their roles in improving predictive accuracy and process simulation capabilities.Engineering-oriented approaches to strain path design are also summarized,highlighting their potential for optimizing formability and service performance.Finally,perspectives on future research directions are presented.

To meet the multifunctional demands of integrated electronics, SiC nanowire (SiCNW) aerogels are attractive due to their lightweight nature, thermal stability, and three-dimensional network structure, yet their intrinsically low conductivity and poor surface activity limit their applications. Compositing with carbon can improve conductivity, yet balancing electrical conductivity and thermal insulation performance remains challenging. Herein, vertical graphene nanosheet arrays (VGNs) were in-situ fabricated to construct an ultra-light and flexible SiCNWs@VGNs core-shell aerogel integrating electromagnetic interference (EMI) shielding, supercapacitor performance and thermal insulation performance. VGNs transform single-point nanowire contacts into multi-point conductive connections, enhancing in-plane electrical conductivity while preserving low density and high specific surface area. This structure facilitates rapid electron/ion transport, resulting in an areal capacitance five times that of pristine SiCNWs aerogel. The abundant interfaces and defects of VGNs promote effective electromagnetic wave attenuation, exhibiting a high EMI shielding effectiveness of 41.50 dB at 1.5 mm, a specific shielding effectiveness of 2787.11 dB cm3 g-1 and EMI shielding stability even after 2000 folding cycles. Importantly, the point-contact core-shell architecture and hierarchical pore structure ensure exceptional thermal insulation performance even when exposed to a 650 degrees C alcohol lamp and a 1300 degrees C spray gun. This work provides a new strategy for designing lightweight, flexible, conductive, yet thermally insulating materials for next-generation integrated electronic systems.

Design and optimization of electrode material structures are critical steps in the development of supercapacitors. This work presented a design strategy based on SiC nanowires (NWs) as supercapacitor electrode with gradient pore structure, superhydrophilicity, and enhanced conductivity. SiCNWs were in-situ fabricated on a carbon fabric substrate radially via chemical vapor deposition (CVD), constructing conical channels with gradient pore sizes that generate capillary forces and promote ion transport. An ultrathin pyrolytic carbon (PyC) shell (4.98 nm) was coated on the SiCNWs, to improve electrical conductivity without compromising pore structure or wettability. SiCNWs@PyC electrodes with a diameter of similar to 0.93 mu m exhibited excellent electrochemical performance from 0 to 60 degrees C. At 25 degrees C and a current density of 0.2 mA/cm(2), the areal capacitance of SiCNWs@PyC electrode was 32.48 mF/cm(2), representing 227.58% of the areal specific capacitance of pure SiCNWs. At 60 degrees C, the capacitance remained high at 28.09 mF/cm(2) under the same current density. The in-situ growth strategy and high mechanical stability of the material enabled the symmetric supercapacitor to maintain outstanding rate performance and cycling stability across a wide temperature range. The SiCNWs@PyC core-shell nanostructure is a promising supercapacitor electrode material, offering valuable insights for the development of next-generation energy storage devices.

Static and dynamic uniaxial tensile responses were investigated to accurately characterize and predict the mechanical properties of PEEK (polyether-ether-ketone) at strain rates ranging from 10−3 s−1 to 200 s−1 and temperatures ranging from 23 °C to 110 °C. The tensile responses showed dependences on the strain rate and temperature, and the dependences of the yield strength and elastic modulus on the temperature and strain rate were studied. A modified phenomenological Sherwood–Frost constitutive model considering a wide range of strain rates and temperatures was established to characterize the tensile mechanical response of PEEK material before yielding based on the experimental data. The results indicate that the model can accurately describe the pre-yield behavior of PEEK under different temperature and strain rate conditions, thus reducing the dependency on experimental data for subsequent researchers, thereby providing a theoretical foundation and modeling framework for the design and performance evaluation of CF/PEEK composite structures.

The heterogeneous microstructure of TC17/TC4 joint manufactured by linear friction welding will reduce the mechanical properties compared with the base metals, of which the strength and ductility are hard to be improved simultaneously by traditional aging heat treatment (AHT), seriously limiting the application of LFW in the manufacturing of TC17/TC4 blisks. To this end, the present work proposes to use electric pulse treatment (EPT) to enhance the strength and ductility of the joint simultaneously by improving its microstructure. The results show that EPT effectively improves the plasticity of the joint compared with AHT. The tensile properties of aging treated joint are similar to that of the as welded joint, which present a strength around similar to 805 MPa and an elongation around similar to 13%. When the joint was electric pulse treated at 550 degrees C and 630 degrees C for 1 h, the elongation increases to 15.8% and 16.3%, which is an increase of 21.5% and 34.7% compared to the corresponding heat-treated joint. The microstructural response under AHT is the aging precipitation behavior of lamellar alpha affected by welding process. Whereas, the microstructural response under electric pulse treatment is driven by local Joule heating effect and the electron wind effect. After EPT, the basket-weave distribution of alpha-lamellae on TC17 side enhances ductility while maintaining strength and the spheroidized alpha phase on TC4 side reduces the microstructural gradient and prevents stress concentration at locations of microstructural discontinuities, thereby improving ductility. This study offers valuable insights for improving the strength and ductility of LFW TC17/TC4 blisks and advancing the application of LFW in aeroengine components.

Silicon carbide nanowires (SiCnws) with high dielectric loss and superior thermal stability attract increasing attention in the field of microwave absorption and thermal insulation. However, the low dielectric constant and no magnetic loss limit their broad application. In this study, a bioinspired highly oriented SiC nanowires arrays with a gradient structure were fabricated on carbon fiber cloth by catalyst-assisted chemical vapor deposition method, showing excellent performance in both microwave absorption and thermal insulation. It was found that the microwave absorption properties were closely related with the metallic catalysts and the SiCnws arrays prepared with Co(NO3)2 as the catalyst had a strong microwave absorption capacity. When the thickness was 1.35 mm, the effective absorption bandwidth was 4.59 GHz (13.41-18 GHz), and the minimum reflection loss (RLmin) reached -37.92 dB at the thickness of 3.10 mm. Meanwhile, the bioinspired oriented SiC nanowires arrays also had excellent thermal insulation and heat preservation effects, making them potential candidates for heat insulation applications. This study not only provides a simple and universal preparation method for oriented SiCnws arrays on carbon fibers, but also offers new research ideas for the wide applications of SiCnws in microwave absorption and thermal insulation.

The electrically assisted (EA) deformation process has received considerable attention in recent years, accompanied by research on current-induced deformation mechanisms. However, there are still challenges in eliminating thermal effects, which have prevented a comprehensive understanding of the underlying current-induced mechanisms. Opting for a single crystal (SC) in research provides advantages in decoupling the nonthermal effect of electric current at smaller scales and eliminating the complex interactions that exist in polycrystalline materials. Therefore, the innovation of this work lies in decoupling the nonthermal effect of electric current and conducting a comprehensive analysis of anisotropic deformation and mechanisms within a Ni-based SC with different crystallographic axes and various current directions during electrically assisted tensile simulation. A significant tension axis direction in the SC during EA tension was induced by the combination of a higher current direction factor (|cosθ|) and a dimensionless factor for the current density (|Jα/J0α|) along the [100] axis. The stress drop within the SC due to the nonthermal effect of electric current generally increased with increasing current direction. This was attributed to the increased dislocation density differences and decreased temperature. The increased stress anisotropy of the SC at a current direction of 45° was attributed to fewer activated (111) slip systems and the pinning effect of more dislocations within these systems. This study advances our understanding of the thermal and nonthermal effects of electric current and offers valuable insights for the informed application of EA deformations in industrial and aerospace settings with SC superalloys.

Design and optimization of electrode material structures are critical steps in the development of supercapacitors. This work presented a design strategy based on SiC nanowires (NWs) as supercapacitor electrode with gradient pore structure, superhydrophilicity, and enhanced conductivity. SiCNWs were in-situ fabricated on a carbon fabric substrate radially via chemical vapor deposition (CVD), constructing conical channels with gradient pore sizes that generate capillary forces and promote ion transport. An ultrathin pyrolytic carbon (PyC) shell (4.98 nm) was coated on the SiCNWs, to improve electrical conductivity without compromising pore structure or wettability. SiCNWs@PyC electrodes with a diameter of ~0.93 u03BCm exhibited excellent electrochemical performance from 0 to 60 u2103. At 25 u2103 and a current density of 0.2 mA/cm2, the areal capacitance of SiCNWs@PyC electrode was 32.48 mF/cm2, representing 227.58% of the areal specific capacitance of pure SiCNWs. At 60 u2103, the capacitance remained high at 28.09 mF/cm2 under the same current density. The in-situ growth strategy and high mechanical stability of the material enabled the symmetric supercapacitor to maintain outstanding rate performance and cycling stability across a wide temperature range. The SiCNWs@PyC core-shell nanostructure is a promising supercapacitor electrode material, offering valuable insights for the development of next-generation energy storage devices.

Grain boundaries play a vital role in determining the mechanical and physical properties of metallic materials. Heat treatment (HT) is widely employed to modify the content and distribution of grain boundaries. However, achieving precise control by HT remains challenging due to the scale mismatch between heat transfer and microstructure evolution. Electric pulse treatment (EPT) offers a breakthrough in microstructure control, by unifying the scales of microstructure and heat generation through a local Joule heating effect, with significant acceleration to microstructure evolution through athermal effects. Those two aspects establish EPT as an effective approach to grain boundary regulation. Despite its advantages, the mechanisms underlying the thermal and athermal effects of EPT remain unclear. To this end, a study of the grain growth kinetics of a nickel-based superalloy with an inhomogeneous microstructure under EPT was carried out through experimental and theoretical approaches. Grain boundary migration behaviors in both coarse- and fine-grained regions were investigated, corresponding grain growth kinetics were established, and effects were validated via annealing twin evolution. The results reveal that EPT accelerates grain boundary migration more than HT, exhibiting a “target effect” where growth rates correlate with grain boundary density. The efficacy of EPT depends on the balance between enhanced grain boundary migration and a reduced treatment time.