The aqueous multivalent metal-ion (Mⁿ⁺ (n denotes the valence/charge number of metal (M) ion, n ≥ 2)) battery is a promising new generation of electrochemical energy storage systems. This battery has several advantages, such as low cost, high safety, and high capacity. However, the acidic aqueous electrolyte environment and the large ionic radius of multivalent metal ions tend to cause failure of the positive electrode structure during cycling. This failure results in a long-term shortage of electrode materials suitable for the reversible storage of multivalent metal ions, severely restricting the development of this system. To address this key bottleneck, this study systematically examines two representative studies conducted by our research group on vanadium-based electrode materials and successfully verifies them in different battery systems. (1) The core achievement is the “Zn²⁺-mediated water dissociation interfacial catalytic storage model”. In aqueous zinc-ion batteries using VN@rGO (three-dimensional porous reduced graphene oxide (rGO) aerogel confined vanadium nitride (VN) nanocrystals) cathodes, Zn²⁺ can polarize interfacial H₂O molecules and induce water dissociation. This enables the generated *OH (where * denotes adsorption sites on the cathode surface) intermediates to undergo reversible adsorption/desorption on vanadium-based interfaces and participate in fast charge storage. This model transforms H₂O in aqueous batteries from a potential source of parasitic reactions into a tunable participant in energy-storage reactions, thereby providing a new perspective on their fast-charging behavior that differs from the conventional ion intercalation/deintercalation and pseudocapacitive mechanisms. Experimental results demonstrate that the Zn²⁺-VN coordination system achieves the theoretically predicted optimal balance between *OH adsorption and desorption. (2) As an extension of this interfacial water/proton chemistry, monoclinic VO₂ nanorod electrodes with tunnel structures are further applied in aqueous manganese-ion batteries to realize efficient Mn²⁺ storage. This storage efficiency is achieved via a reversible ion intercalation/deintercalation mechanism. Thus, this study reveals the Mn²⁺/H⁺ cointercalation behavior and clarifies the intrinsic mechanism of irreversible vanadium dissolution induced by high proton activity. Based on these results, a hydrogen-bond reconfiguration-driven proton-transfer regulation strategy is proposed to optimize the electric double-layer structure at the electrode/electrolyte interface, effectively suppress excessive interfacial proton activity and side reactions, and enable the VO₂ electrodes to achieve excellent rate performance and cycling stability. This work indicates that the development of aqueous multivalent metal-ion batteries requires high-capacity electrode materials and coordinated storage chemistry system involving metal ions, H₂O molecules, and electrode interfaces.

The molten salt reactor (MSR) is an important reactor type in Generation IV nuclear systems. However, the high-temperature, corrosive, and irradiation-coupled environment of MSRs compromises the chemical stability and service reliability of structural materials. Nickel-based alloys, featuring an fcc matrix with high thermal stability and low chemical activity, are promising candidates but remain susceptible to selective corrosion dissolution, Te-induced corrosion cracking, and irradiation-accelerated corrosion. This review summarizes the multifield-coupled failure mechanisms of Ni-based alloys for MSRs and outlines a four-dimensional modification framework of “composition optimization, secondary phase regulation, grain boundary regulation, and coating protection”. Lowering the Cr content and optimizing the Mo / W ratios collectively suppress selective dissolution; secondary phase/oxide dispersion strengthened particles trap defects and block diffusion; grain boundary engineering suppresses Te penetration by increasing the fraction of low-Σ boundaries; Ni-W or silicon carbide coatings provide terminal protection. Future efforts should focus on in situ multifield characterization, machine learning-based design, and environment-adaptive regulation of Ni-based alloys to achieve their long-term reliability and engineering application in MSRs.

Currently, there is rapid development of lead-cooled fast reactors (LFRs) as a main type of Generation IV nuclear reactor in China. High-Si austenitic stainless steel is a candidate structural material for important LFR components, such as fasteners, due to its excellent high-temperature mechanical properties and corrosion resistance to liquid Pb-Bi. However, high-Si steel accelerates the precipitation of secondary phases, such as M₂₃C₆, M₆C, χ phase, G phase, and ferrite, during long-term high-temperature aging, thereby reducing microstructural stability and degrading mechanical properties. Therefore, while high-Si steel enables better corrosion resistance, the problem of high-temperature microstructural stability remains a critical issue to resolve. This review focuses on the use of high-Si austenitic stainless steel for LFR fasteners, with the introduction of the Si alloying design principle and a summary of the evolution characteristics of secondary phases induced by Si addition in austenitic steels. Furthermore, an alloying strategy to improve microstructural stability based on experimental findings is proposed along with an outlook toward future developments.

The fabrication of ultrafine conductive patterns serves as a core enabling technology propelling the evolution of electronic devices toward miniaturization, flexibility, and high-density integration. Driven by the rapid development of emerging fields such as Internet of Things terminals, flexible wearable electronics, and microenergy devices, the demand for electronic devices in terms of pattern linewidth precision, cross-substrate compatibility, and complex structure adaptability continues to escalate. However, traditional fabrication techniques face inherent bottlenecks in balancing precision control, flexible adaptability, and cost-effective fabrication. Laser-induced transfer (LIT) technology, leveraging its unique advantages of high precision, noncontact processing, and broad material compatibility, has remarkably improved the resolution of ultrafine patterns and expanded cross-material adaptability. This technology provides an innovative technical solution for addressing traditional process bottlenecks in this domain. In recent years, LIT-related research has achieved substantial advancements in mechanistic elucidation, process optimization, and application extension. Nevertheless, a systematic review synthesizing its key progress and evolving trends is still lacking. Accordingly, this review systematically summarizes the current research status and future development directions of LIT technology for the fabrication of ultrafine conductive patterns. First, it traces the technological evolution of LIT from conceptual initiation to multifield practical applications, elaborating on the core transfer process of LIT and its inherent advantages in ultrafine conductive pattern fabrication. It subsequently delves into two major transfer mechanisms, namely, thermally dominated and momentum-transfer-driven mechanisms and systematically discusses the regulatory effects of critical process parameters (e.g., material intrinsic properties, laser process parameters, and the donor-receiver interface distance) on the quality of ultrafine conductive patterns. On this basis, this review conducts a comparative analysis of the performance characteristics and suitable application scenarios of multiple technical implementation routes, such as single-pulse transfer, multipulse superposition transfer, and integrated composite processes. Finally, this review systematically summarizes the typical application cases of LIT-fabricated ultrafine conductive patterns in fields including microelectronic circuit repair, high-performance sensor fabrication, flexible wearable electronics, and battery manufacturing.

Tungsten alloy, known for its high hardness, thermal stability, and excellent nuclear radiation shielding performance, is a critical material for radiation shielding applications. It is widely used in aerospace, national defense, and medical fields. However, tungsten alloy has drawbacks such as high density and processing difficulty, which limit its applicability in high-efficiency, miniaturized, and lightweight designs, particularly in nuclear medical treatment and nuclear-powered flight devices. A double-layered W/Mg structure is expected to serve as a next-generation nuclear radiation shielding material. Due to the significant differences in melting temperatures and coefficients of thermal expansion between W and Mg, conventional soldering methods are ineffective for joining them. In this study, a W90 tungsten heavy alloy and AZ31B magnesium alloy were successfully bonded using an ultrasonic-assisted soldering method with pure Sn. The bonding temperature was 250 ^oC, and the ultrasonic duration was 4 s. The interfacial microstructure of the W90/Sn/Mg joint under varying ultrasonic power levels was analyzed using SEM and EDS. Additionally, the shear strength of the joint was tested to assess the impact of ultrasonic power on interfacial bonding and mechanical performance. The results indicated that effective bonding formed at the W90/Sn interface, with Ni₃Sn₄ compounds appearing between the (Ni, Fe) matrix and Sn. The seam consisted of a β-Sn matrix phase and Mg₂Sn compounds, with an Mg₂Sn layer forming on Mg/Sn interface. As ultrasonic power increased, joint width decreased while the Mg₂Sn layer thickness increased. The shear strength of the joint initially increased with ultrasonic power but later decreased. At ultrasonic power levels of 100 and 150 W, the joint strength reached a maximum of 10.5 MPa, with failure occurring at the W90/Sn interface. When ultrasonic power increased to 200 W, joint strength declined, and fracture occurred at the Mg₂Sn layer. The acoustic pressure distribution of liquid Sn during the ultrasonic-assisted soldering process was simulated. During a single ultrasonic cycle, the acoustic pressure of liquid Sn oscillated periodically from negative to positive and back to negative values. The maximum acoustic pressure was observed at the center of the liquid Sn, gradually decreasing toward the edges. The cavitation effect, driven by collapsing bubbles, generated high temperatures, high pressures, micro-jets, and shock waves, as explained through theoretical calculations. Based on the Keller-Miksis equation, as ultrasonic power increased, the ratio of the cavitation bubble radius to its initial radius increased from 16.3 to 47.7, with collapse velocities ranging from 3262 m/s to 6985 m/s. According to the Noltingk-Neppiras theory, as acoustic pressure increased, cavitation-induced temperatures rose from 14614 K to 24989 K, while pressure increased from 1.08 × 10⁵ MPa to 9.45 × 10⁵ MPa. The generated temperature and pressure were sufficient to break the Mg alloy’s oxide film and promote interfacial reactions.

With the advancement of high-thrust liquid rocket engine toward higher chamber pressure and specific impulse, the turbine pump system of the gas generator is being increasingly exposed to extreme high-temperature and high-pressure oxygen-enriched environments. This exacerbates the risk of metal-oxidation combustion failure of superalloy components. The production of high-performance and complex-structured superalloy parts via selective laser melting technology has emerged as a key research area in the manufacture of critical aerospace components. Therefore, the investigation of the oxygen-enriched combustion mechanism of high-temperature alloy materials fabricated using the selective laser melting technology is of great practical significance. This study investigated the effect of heat treatment on the flame retardant property of GH4169 alloy produced via selective laser melting using self-developed experimental equipment designed for oxygen-enriched combustion testing of metal materials. A high-speed camera was used to observe and record the combustion process. The microstructure and combustion morphology of the alloy were analyzed using OM, SEM, and EDS. The as-deposited sample exhibited a typical fish-scale molten pool morphology, with numerous low-melting-point Laves phases precipitating in the interdendritic regions and grain boundaries. Following heat treatment at 980 ^oC, most Laves phases dissolved, and needle-like and short rod-like δ-Ni₃Nb phases precipitated at the grain boundaries and in the interdendritic regions. Upon increasing the solution temperature to 1080 ^oC, the volume fraction of precipitated phases was significantly reduced. Consequently, only a small number of nano-sized Laves particles were formed within the grains and a certain amount of blocky carbides were located at the grain boundaries. Combustion resistance testing revealed that the as-deposited sample exhibited the poorest resistance, whereas samples heat-treated at 1080 ^oC demonstrated the highest resistance. Further, microstructural analysis confirmed that the combustion behavior was closely related to the type and volume fraction of the precipitates within the matrix. Laves phases with high Nb content melted early in the combustion, thereby accelerating the reaction owing to the high combustion heat of Nb. The δ phases formed after heat treatment at 980 ^oC also promoted combustion. Thus, these findings suggest that eliminating the low-melting-point phases and controlling the types of precipitated phases are key strategies for enhancing the flame retardant properties of GH4169 alloy.

Cracking and insufficient strength at high temperatures are major challenges in the manufacturing of additive-manufactured nickel-based superalloys, but can be effectively solved by a composition design based on solid solution elements. In this study, the amounts of γ′ phases, cracks, lattice mismatch, and topological close-packed (TCP) phase in additively manufactured Ni-based superalloys were investigated through thermodynamic calculations, OM, XRD, SEM,TEM, and tensile property tests. The preliminarily optimized ZGH-10 alloy exhibited a good microstructure and excellent tensile properties, with a solid solution strength and crack area percentage of 236 MPa and (1.3 × 10^-4)%, respectively. The lattice mismatch of the ZGH-10 alloy (-0.26%) contributes to square γ' phases. After thermal exposure to 1000 ^oC for 500 h, no TCP phase precipitation appears in the ZGH-10 alloy. At 25 ^oC, 760 ^oC, and 1000 ^oC, the ZGH-10 alloy delivers tensile strengths of 1290, 1089, and 555 MPa, respectively, and elongations of 17.0%, 10.8%, and 28.5%, respectively, showing excellent strength and ductility of the alloy.

Owing to its favorable mechanical properties derived from a ferrite-pearlite dual-phase microstructure, 60 steel is widely used in load-bearing components such as bearings and transmission gears, as well as in impact-resistant structures in vehicles and ships, underscoring its potential for dynamic engineering applications. In this study, plate-impact experiments were performed using a single-stage gas gun. The shock-induced microstructural response of 60 steel was examined using SEM and EBSD. Free-surface velocity profiles indicate that spall strength initially increases with peak stress and subsequently approaches saturation. Damage morphology reveals that brittle fracture is the dominant failure mechanism, characterized by the nucleation and propagation of cleavage cracks. At higher peak stresses, ductile damage becomes increasingly evident through the nucleation, growth, and coalescence of microvoids. Grain boundaries, cementite lamellae, and ferrite-cementite interfaces serve as preferential damage-nucleation sites. Within pearlite colonies, microcracks tend to propagate along directions forming larger angles with the cementite lamellae. EBSD analysis further confirms that grain orientation governs cleavage-crack propagation, with microcracks preferentially advancing along the {001} crystallographic planes.

Zirconium alloy sheets exhibit limited formability at room temperature, often leading to cracking during the fabrication of spacer grids in nuclear reactors. This study presents stamping experiments conducted on Zr-4 sheets, with microstructure and texture characteristics measured at various positions along the longitudinal section using EBSD. The in-grain misorientation axes method was employed to analyze deformation mode selection. Supported by finite element method simulations, a visco-plastic self-consistent model was applied to quantify the activation of deformation modes and elucidate the relationship between texture evolution and slip/twin activity. In addition, the effects of strain paths on crack formation mechanisms were investigated. The results indicate that cracking primarily occurred around the punch radius. Positions near the punch radius followed a plane strain path, whereas regions along the slope wall and die radius exhibited a uniaxial tension path. Prismatic <a> slip was found to dominate deformation across all loading strain paths. Near the die radius, pyramidal <c + a> slip and tensile twinning were activated to accommodate stamping deformation, resulting in the formation of new texture components aligned along the rolling direction. The increase in basal texture strength around the punch radius was attributed to basal <a> slip, serving as a secondary dominant slip system. Furthermore, prismatic slip, in coordination with basal slip, facilitated the texture transition from a double-peak structure to a basal texture.

The Ti551 alloy exhibits exceptional thermal stability, retaining over 80% of its room-temperature strength within 300-400 ^oC, outperforming most α-type Ti alloys. Consequently, it has emerged as the primary structural material for applications in extreme operating environments, such as deep-sea oil drilling pipes. Despite this advantage, the Ti551 alloy exhibits considerably complex thermal deformation behavior and microstructural evolution. Establishing the alloy's precise hot processing window is critical to broaden its engineering applications. Therefore, this study investigated the thermal deformation behavior of the Ti551 alloy using a Gleeble-3500 thermal simulation tester. Specifically, isothermal compression tests were conducted over the temperatures (T) of 800-1100 ^oC and a strain rate (\dot{\epsilon }) of 0.001-10 s^-1. Considering friction and temperature corrections, strain-compensated Arrhenius (SCA) and back-propagation artificial neural network (BPANN) models were selected to establish a constitutive model of the Ti551 alloy. The accuracies of both models were evaluated using the correlation coefficient, average absolute relative error, and relative error. The results demonstrate that the BPANN model outperformed the SCA model, yielding superior accuracy in predicting the flow stress. Thereafter, a hot processing map was constructed based on the dynamic materials model, and the corresponding microstructural evolution during thermal compression was systematically analyzed. Analysis of the hot processing map identified the optimal processing window with the following parameters: \dot{\epsilon } = 0.001-0.1 s^-1 and T = 900-1050 ^oC. Additionally, the instability zone was primarily concentrated in the high-T, high-\dot{\epsilon } region (T ≥ 1000 °C, \dot{\epsilon } ≥ 1 s^-1). These findings demonstrate that the deformation T and \dot{\epsilon } substantially influenced the flow stress. Specifically, the flow stress markedly increased with the decrease in T or increase in \dot{\epsilon }. During hot compression, the microstructural evolution of the Ti551 alloy exhibited a close relationship with T and \dot{\epsilon }, and the dynamic recrystallized grain size notably decreased as T decreased or \dot{\epsilon } increased. Furthermore, the dominant dynamic recrystallization (DRX) mechanisms during hot deformation comprised continuous and discontinuous DRX processes.

Niobium-based alloys are commonly used as superconductors in particle accelerators and fusion Tokamaks. However, magnets made of these alloys experience considerable radiation damage, particularly from helium transmutation products in nuclear reactors, which tend to aggregate at grain boundaries (GBs) and phase boundaries (PBs). This aggregation severely degrades the material's performance. Furthermore, niobium is highly prone to oxidation at high temperatures, further restricting its applications in extreme environments. Recent studies have demonstrated that Cu/Nb multilayer composites fabricated through accumulative roll bonding (ARB) exhibit high yield strength, acceptable ductility, and excellent radiation resistance, making them highly promising for nuclear industry applications. In Cu/Nb multilayer composites with fcc/bcc structures prepared via ARB, interfacial instability and strain concentration can occur during deformation due to the high three-dimensional incompatibility of heterophase interfaces. In this study, Cu/Nb polycrystalline multilayer composites were prepared using ARB. In situ tensile tests were conducted using SEM to investigate the slip transfer and blocking behaviors at the GBs and PBs. These behaviors were studied by observing the slip trace alignment and surface morphology continuity. Slip transfer behavior in Cu/Nb multilayer materials was elucidated through statistical analysis of the Luster-Morris parameter (m' = cosψcosκ,where ψ and κ represent the angles between the two slip plane normal directions and the two slip directions, respectively) and residual Burgers vector (Δb = | b_s2-b_s1|, where b_s2and b_s1 are the two unit Burgers vectors of the slip systems in sample coordinate system). In the Cu layer, slip transfer occurs at the GBs when m′ exceeds 0.77 and Δb is less than 0.029. In the Nb layer, slip transfer occurs when m′ exceeds 0.81 and Δb is less than 0.250. For the Cu/Nb PBs, slip transfer occurs when m′ exceeds 0.93 and Δb is less than 0.173. Notably, the minimum m′(m_{\mathrm{t}\mathrm{h},\mathrm{m}\mathrm{i}\mathrm{n}}^{\text{'}})and maximum Δb (Δb_{th, max}) for slip transfer at Cu GBs are lower than those at Nb GBs, indicating that slip transfer is more likely to occur at GBs in the Cu layer. The m_{\mathrm{t}\mathrm{h},\mathrm{m}\mathrm{i}\mathrm{n}}^{\text{'}} for slip transfer at Cu/Nb PBs is higher than that at both Cu and Nb GBs, whereas the Δb_{th, max} lies between the two types of GBs. This phenomenon can be attributed to the more complex structure, higher interface energy, and lower shear strength of Cu/Nb PBs than GBs. To achieve slip transfer across fcc/bcc PBs, a larger resolved shear stress is thermodynamically required; and kinetically, the slip systems on both sides of the PB must be closely aligned, corresponding to a higher m_{\mathrm{t}\mathrm{h},\mathrm{m}\mathrm{i}\mathrm{n}}^{\text{'}} and a moderate Δb_{th, max}.

Structural-functional integrated Cu-alloy/Ti-alloy bimetals combine the advantageous properties of both constituents and therefore exhibit considerable potential for multifunctional applications. However, controlling the interfacial microstructure and achieving sufficient interfacial strength remain significant challenges in Cu-alloy/Ti-alloy systems. This study investigates the evolution of the interfacial microstructure, the ordering behavior of interfacial intermetallic compounds (IMCs), and the relationship between interfacial structure and mechanical performance, aiming to clarify the formation pathway of IMCs and its effect on the interface strength of Cu-alloy/Ti-alloy bimetals. QAl10-5-5/TC6 bimetals were fabricated via diffusion bonding using Ag interlayer (adding Ag foil as interlayer or electrodeposited Ag interlayer on QAl10-5-5 alloy). The resulting interfacial microstructures and shear strengths were systematically characterized, and the corresponding strengthening mechanism was clarified. For the QAl10-5-5/Ag foil/TC6 bimetals, the interfacial strength reached a maximum of 200 MPa at a bonding temperature of 850 ^oC. Meanwhile, for the Ag layer deposited QAl10-5-5/TC6 bimetals, the fine-grained structure of the electrodeposited Ag layer promoted metallurgical bonding, and the QAl10-5-5/TC6 bimetals achieved maximum interfacial strength of 217 MPa at a bonding temperature of 835 ^oC. Moreover, an “affected zone” formed on the TC6 alloy side of Ag layer deposited QAl10-5-5/TC6 bimetals, consisting of a TiAlCu₂ reaction layer with a thickness of ~1 μm, and submicron scale Ti₂Cu and Ti₃Al phases, in which a semi-coherent interface occurred between Ti₃Al and α-Ti. Theoretical strengthening analysis of Ag layer deposited QAl10-5-5/TC6 bimetal revealed that the grain refinement strengthening and precipitation strengthening enhanced the property of the “affected zone” on the TC6 alloy side.