Magnesium hydride (MgH2) is a promising solid-state hydrogen storage material for large-scale applications, owing to its high gravimetric capacity and natural abundance. However, its practical implementation is hindered by high thermodynamic stability and sluggish kinetics, originating from strong Mg-H bonds and limited hydrogen diffusion, which typically require elevated temperatures and prolonged cycling. Moreover, existing catalytic systems frequently suffer from inadequate dispersion, interfacial instability during cycling, and a lack of quantitative understanding of the cooperative effects between oxygen vacancies and multivalent Ce. To address these issues, a Co/CeO2@C composite catalyst was synthesized through a hydrothermal-calcination method and incorporated into MgH2 via ball milling. The microstructural characteristics, hydrogen storage properties, and underlying reaction mechanisms were systematically investigated using X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Pressure-Composition-Temperature (PCT) tests and Johnson-Mehl-Avrami-Kolmogorov (JMAK) kinetic fitting. Evaluation based on microstructure, hydrogen uptake/release capacities at varying doping levels, and corresponding activation energies revealed that the composite with 6 wt% Co/CeO2@C exhibited a hydrogen uptake of 5.74 wt%. At 300 degrees C, the 6 wt% composite released 5.15 wt% H2 within 100 min, demonstrating its superior dehydrogenation performance at this doping level. The activation energy decreased from 145.43 kJ center dot mol-1 to 93.35 kJ center dot mol-1, and this enhancement is ascribed to a triple synergistic mechanism of "hydrogen spillover-electron transfer-confinement stabilization". Co offers active sites for hydrogen dissociation, oxygen vacancies in CeO2 promote hydrogen diffusion, and the carbon matrix suppresses particle agglomeration. This study contributes to quantitatively understanding the synergy between oxygen vacancies and multivalent Ce, establishes a clear "microstructure-catalytic mechanism-macro-performance" correlation, and offers new insights for the practical deployment of Mg-based hydrogen storage materials. It is noted, however, that the key findings presented herein align closely with trends reported in prior literature, highlighting the consistent performance landscape observed for this class of catalytic modifiers.

This study presents a novel lever-type inertial amplification (LIA) plate designed for enhanced low-frequency sound insulation. The structure consists of a plate periodically attached with LIA metamaterials, each employing a dual-hinged lever and a tip mass to achieve the desired inertial amplification. A semi–analytical vibro–acoustic model, integrating finite element modeling with the Rayleigh integral for sound radiation, is developed to predict the acoustic response of the LIA plate. The results reveal excellent sound insulation at low frequencies, which is validated against both commercial software and experimental measurements. The mechanism underlying this superior low–frequency performance is elucidated, showing that the inertial amplification effect contributes to the formation of a wide attenuation band. Comparative studies with conventional locally resonant plates demonstrate that the LIA plate achieves significantly improved low-frequency sound insulation over a broader frequency range. The influences of lever rigidity and vertical support stiffnesses on the IA bandgap are systematically investigated, revealing stiffness-dependent transitions and coupled tuning mechanisms within the LIA unit. To leverage these useful properties, a tunable design incorporating shape memory alloys is explored. The new design demonstrates that temperature–driven material and geometric variations can effectively regulate the dynamic response and sound insulation performance of the proposed device. These findings suggest that the LIA plate provides a robust and practical solution toward overcoming the challenges of low–frequency noise control.

This study investigates the effects of pulsed magnetic field aging treatment on precipitate evolution and mechanical properties of the solidified microstructure in the ZL114A-RE aluminum alloy, and optimizes the corresponding aging parameters. The alloy used is ZL114A modified with 0.25 wt.

Magnesium-based hydrogen storage materials (MgH2) are promising for solid-state hydrogen storage (7.6 wt% theoretical capacity, abundant resources, high safety) but suffer from high dehydrogenation temperatures (>300 °C) and slow kinetics. Catalytic modification strategies for MgH2 are systematically summarized and compared in this review, encompassing both single-component catalysts (e.g., transition metals, carbon-based materials, metal oxides) and multi-component synergistic systems (e.g., metal-carbon hybrids, high-entropy alloys). The mechanisms by which these strategies address key bottlenecks are elucidated: transition metals like Ni reduce the dissociation energy of Mg–H bonds through 3d-sp orbital hybridization. N-doped carbon nanotubes enhance cycle stability via electronic regulation and nanoconfinement. Metal oxides optimize hydrogen diffusion paths through defect engineering. In multi-component systems, synergistic effects (e.g., dual-channel electron/hydrogen transport in Ni@C core-shell structures, interface stabilization via configurational entropy in high-entropy alloys) lead to breakthrough performance. Optimized systems can lower the initial dehydrogenation temperature to below 150 °C while maintaining a hydrogen storage capacity of over 6.5 wt%. Furthermore, this review bridges experimental advances with theoretical insights from first-principles calculations and machine learning screening. It also addresses persistent challenges and outlines future research directions for practical application. This work provides crucial theoretical and experimental guidance for developing high-efficiency Mg-based hydrogen storage materials. Specifically, it elucidates the priority of core challenges and provides quantitative design criteria for catalysts, laying a foundation for industrial application.

This study examines the combined influence of pulsed magnetic fields and the rare earth element Yb on the solidification microstructure and properties of Al-6Mg-0.6Mn-0.2Fe aluminum alloys (varying rare earth content: 0

The application of hydrogen energy in real life is closely related to the efficient storage technology of hydrogen. As a typical representative of AB-type hydrogen storage alloys, TiFe-based alloys have broad application prospects for many industries due to their large capacity, high energy conversion efficiency, and good safety. TiFebased alloys can absorb and release hydrogen at near room temperature and atmospheric pressure. However, the industrial application of TiFe-based alloys is hindered by their susceptibility to readily forming oxide films. To solve the above problems, a future research direction is proposed. Based on the hydrogen storage mechanism of titanium-iron-based alloys, this paper analyzes and summarizes the effects of different metal element substitutions on the kinetic properties, thermodynamic properties and hydrogen storage capacity of the alloys. At the same time, the preparation techniques of TiFe-based alloys in recent years were compared, including vacuum melting method, mechanical ball milling method, cold rolling method, high pressure torsion method, rapid quenching method, vapor deposition method, and re-hydrogenation/dehydrogenation method. In addition, the future development trend and research direction of the alloy are prospected.

Surface modification by the addition of transition metals with high catalytic activity is widely considered by scholars as the most effective way to enhance the activation properties and hydrogen absorption/desorption kinetics of TiFe-based alloys. In this paper, the cast experimental alloy with the standard composition of Ti1.08Zr0.1Y0.02Fe0.6Ni0.3Mn0.2 was synthesized by vacuum induction melting. Ball-milled alloy powders were prepared by high-energy ball milling of Y-TiFe-based alloys by adding different mass fractions of the transition group metal V. The microstructures and phase compositions of the alloys before and after hydrogen absorption/ desorption were characterized, and the activation properties, hydrogen absorption/desorption kinetics, and thermodynamic properties of the experimental alloys were determined by a Sivert's-type semi-automatic P-C-T hydrogen storage tester. The results show that the addition of transition metal V mechanical ball milling significantly improves the surface state of the alloy, generates new catalytic activity centers, and accelerates the transfer rate of hydrogen atoms on the alloy surface. The composite V ball mill alloy showed good activation properties and hydrogen absorption and desorption kinetics when the V addition was 7 wt%, and the experimental alloy can be fully activated with only 1 cycle of hydrogen absorption/desorption at 150 degrees C and 3 MPa H2 pressure, and there was no activation gestation period. Meanwhile, the composite ball-milled alloy had an addition of 7 wt% V reached a hydrogen absorption saturation rate (Ra 100) of 98.1% at 100 s and had the smallest absolute enthalpy change of hydrogen absorption/desorption of 21.2 kJ/mol and 22.9 kJ/mol, respectively, which exhibited better hydrogen absorption kinetics and thermodynamic properties. Particle size reduction, grain refinement, and transition metal surface capping catalysis are the main reasons for improving the activation properties, hydrogen absorption and desorption kinetics, and thermodynamic properties of the alloy.

Hydrogen storage using metal hydrides has a promising future due to its advantages of safety, efficiency, cheapness and cleanliness. In this experiment, the Ti1.08Zr0.1Y0.02Fe0.6Ni0.3Mn0.2+10 wt% M (V, Ni and Pd) composite alloy was produced by co-mingling highly active transition metals (V, Ni and Pd) with Ti1.08Zr0.1Y0.02Fe0.6Ni0.3Mn0.2 alloy through ball milling. Then, the activation properties, hydrogen absorption and desorption kinetics, and thermodynamic properties of the alloys were estimated. The results revealed that the catalyst ball milling not only decreased the size of the alloy particles and shortened the diffusion path but also generated new catalytically active centers and increased the diffusion channel of the alloy. The composite Pd ball-milled alloys exhibited superior activation behaviors and hydrogen absorption dynamics, reaching a hydrogen absorption saturation rate of 96.34 % at 100 s, without any activation incubation period at 150 degrees C, compared to the composite V and Ni ball-milled alloys, which achieved hydrogen absorption saturation rate of 93.34 % and 93.34 % at 100 s, respectively. Nevertheless, the composite V ball-milled alloy showed better hydrogen desorption kinetics and thermodynamic properties. Its hydrogen desorption saturation rate was 97.24 % at 90 degrees C, and the absolute values of the enthalpy change of its hydrogen absorption and desorption were the smallest of the three composite alloys, at 21.3 kJ mol-1 and 23.0 kJ mol-1, respectively. Since the electronegativity of V (1.63) was lower than those of Ni (1.91) and Pd (2.20), it is more favourable for reducing the bond energy of the Y-H bond.

With the widespread trend in industry towards greater miniaturization, precision metal micro-parts are gaining importance. The successful fabrication and operation of micro-components provide opportunity to produce miniaturized machines and mechanical systems. Further commercialization of the microsystem technology requires cost effective microfabrication methods for mass production of micro-metal parts. Micro-metal injection molding (μ-MIM) is considered a promising process for high-volume, low-cost production of micro components especially with complex geometries. However, there are some limitations to apply conventional MIM feedstock to μ-MIM, such as incomplete filling of die cavity, powder-binder separation, insufficient demolding strength, low sintering density and dimension instability. In this paper, the development of new binder system and feedstock formulation with micro-sized 17-4PH stainless steel powders, optimization of injection molding, debinding and sintering steps to achieve stable geometry, dimension and microstructure is reported. The capability of μ-MIM is demonstrated by manufacturing of high precision micro-gears and micro-hinge capture products.

Magnesium metal and its hydride have the characteristics of high hydrogen storage capacity, which is suitable for storing hydrogen energy. In this paper, VS2/NC catalyst supported on nanosheet carbon was synthesized by hydrothermal method with organic matter as raw material, then the MgH2 + x wt.% VS2/NC (x = 0, 3, 6, 9) composites were prepared by ball milling with MgH2. The phase characterization of the composite material showed that the VS2 and MgH2 phases in the composite material remain stable during ball milling and subsequently, the hydrogen absorption/desorption cycle. There were V4+ and V2+ ions (an atomic ratio of 3.77:1) in the catalyst. At 593 K, the capacities of the composites were 5.71, 6.11, 5.62, and 5.33 wt.% H2, respectively. The time to reach the maximum hydrogen desorption capacity of 95% was 190, 30, 20, and 23 min, respectively. The dehydrogenation activation energy of the material with x = 6 is reduced by nearly 50 kJ/mol H2. The initial dehydrogenation temperature of the material decreases to 323 K. Because of the valence state transition between V ions, the band gap of the composite material is narrowed, which significantly improves the hydrogen absorption and desorption reaction kinetics.

Hydrogen energy is regarded as the most promising clean energy in the 21st century. The efficient and safe use of hydrogen energy has become one of the research hotspots. Therefore, solid-state hydrogen storage has gradually attracted the research interest of people. MgH2 has a high hydrogen storage content and can be used as a carrier for hydrogen storage. However, the kinetic and thermodynamic properties of MgH2 are poor, and it requires a high temperature to release and store hydrogen. Therefore, it is necessary to modify MgH2. Catalyst modification research is one of them. This paper mainly introduces the progress of research on MgH2 modification by different kinds of new catalysts in recent years., including carbon-based supported materials, metals and metal oxides, MXA and MXene materials, and metal compounds. The catalytic effects of various catalysts are summarized in detail, and the catalytic mechanism is analyzed. Finally, the prospect of new hydrogen storage material catalysts is made. These conclusions will be helpful to those researchers who study MgH2 hydrogen storage material catalysts.

The limited practical application of commercial MgH2 is hindered by its sluggish hydrogen absorption and desorption kinetics. In this paper, MgH2 particles with smaller sizes were successfully prepared by mechanical ball milling, and the microstructure of ball-milled MgH2 was analyzed by XRD, SEM, and TEM. The addition of ball milling energy increases the surface energy of the material and the fracture of the Mg-H bond. As a result, the surface activation energy of the material is reduced. Furthermore, extending the milling duration results in a notable expansion of the nanocrystalline domains present on the surface of MgH2 powder. At 613 K, the MgH2 ball milled for 15 h can absorb 5.512 wt% H-2 in 7.8 min, and it takes 75 min to release 5.124 wt% H-2 and its dehydrogenation activation energy is reduced from 136.0 to 126.69 kJ/mol H-2. The initial dehydrogenation temperature of the MgH2 sample milled for 15 h was 81 K lower than that of the original MgH2 sample, and the initial dehydrogenation temperature was only 447 K. This work can provide theoretical guidance for the use value of commercial MgH2.

This paper presents the preparation of the parental experimental alloy, featuring a standard composition of Ti1.08Y0.02Zr0.1Fe0.7Ni0.3Mn0.2, via the vacuum induction melting technique. Subsequently, the Ti1.08Y0.02Zr0.1Fe0.7Ni0.3Mn0.2 alloy, with an addition of 2 wt% Ni, underwent mechanical ball milling to yield a TiFe-based composite for experimental purposes. The results of the experimental tests indicate that the composite alloy's phase composition comprises the TiFe primary phase, with a minor quantity of ZrMn2 phase segregated on the surface of the primary TiFe phase, as well as Ni phase. The alloy, which underwent ball-milling for 15 min, displayed excellent activation characteristics, featuring a 12-s incubation period at 150 °C and a hydrogen pressure of 3 MPa. Furthermore, the hydrogen absorption capacity was 1.72 wt% at 90 °C and 33 min. The decrease in particle size and grain refinement of the ball-milled alloy resulted in an increase in the grain boundary specific surface area, which provided more nucleation sites for the hydrides of the ball-milled alloy and enhanced the hydrogen absorption and desorption kinetic performance of the alloy. The thermodynamic properties test indicated that the absolute values of enthalpy (ΔH) and entropy (ΔS) changes exhibited a decreasing trend followed by an increase as the ball milling time extended from 5 min to 180 min during the hydrogen absorption and desorption process. The grain refinement occurring in short-term ball milling and the agglomeration occurring in long-term ball milling are the primary reasons for the variations in the alloy powder. The smallest absolute values of enthalpy and entropy changes were observed for the alloy ball-milled for 15 min, at 19.1 kJ/mol and 22.3 kJ/mol, respectively.

TiFe alloy can store hydrogen at room temperature and low hydrogen pressure, and its theoretical hydrogen storage capacity is up to 1.8 wt%. However, TiFe alloy needs to be activated at high pressure (5 MPa hydrogen) and high temperature (673-723 K), which limits the practical application of TiFe alloy. The as-cast Ti21.7Y0.3Fe16Mn3Cr alloy was milled for 0, 0.5, 0.75, 1, and 3 h to study the effects of ball milling on phase structures and hydrogen storage performances. Emphasis was focused on the activation process of as-milled alloys at different temperatures, including the activation process at 483, 443, and 403 K. The results show that the alloys were consisted of TiFe phase, and [Fe, Cr] solid solution. The nanocrystalline boundary produced by milling and the phase boundary provided by the second phase provide a large number of channels for hydrogen diffusion and promote the improvement of hydrogen storage performances. The time required for activation process of as-milled alloys was significantly reduced, and the activation time of as-milled (0.75 h) was only 4 min, and its enthalpy variation for hydrogen absorption and desorption was 22.943 and 26.215 kJ mol-1 H2, respectively.(c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Sm5Mg41 + x wt% nano-graphite (NG) (x = 0, 2, 4, 8, 12) composites are synthesized via ball-milling. The influences of NG content on microstructure and hydrogen storage properties of the composites are re-searched systematically. The composites consist of Mg, Sm5Mg41, SmMg3, and NG. Nano scale Sm3H7 and MgH2 phases are observed after the hydrogen absorbing, and the newly formed Mg phase and the re-maining Sm3H7 phase appear after hydrogen desorbing. NG is embedded in the surface of the composites in the form of nanosheets. Nanocrystalline Mg and some microscopic defects, including twin crystal, grain boundaries, and dislocations can be observed in the dehydrogenated sample. Such microscopic defects and nanocrystalline boundaries can reduce the total potential barrier needed to overcome during the hydrogen absorption/desorption reactions and thus the hydrogen storage kinetics of the alloy are improved. For the composites with x = 2, 4, 8 and 12, the activation energies of hydrogen desorption are 132.08, 128.06, 112.90, and 112.35 kJ/mol H2, respectively. The enthalpy changes for the hydrogen absorption are evaluated to be - 79.18, - 78.09, - 76.30, - 76.10 kJ/mol H2, indicating that the addition of NG had no obvious effect on the thermodynamic properties of the composites.(c) 2022 Elsevier B.V. All rights reserved.

The recrystallization and inhibitor precipitation behaviors of rare earths under water cooling after holding for different times of oriented silicon steel hot rolled at 1200°C in the ferrite zone with 30% deformation were analyzed using Gleeble 1500D, SEM,TEM and ICP. The results showed that: during the hot rolling of oriented silicon steel in the high temperature ferrite zone, only dynamic reversion occurred, no dynamic recrystallization occurred, and the amount of precipitates did not increase significantly; after deformation at 1200°C, static recrystallization occurred after holding for about 20s, and the inhibitor started to precipitate and grow. The higher the recrystallization rate, the faster the volume fraction of precipitates. After the deformation, the amount of Cu 2 S and MnS in the precipitates was similar. At 64% recrystallization rate, MnS increased by about 8% and Cu 2 S increased by about 23%. At the same time, most of the precipitates were precipitated in the crystal, and gradually nucleated and grew at the grain boundary when the holding time was extended. After rare earth lanthanum and cerium were added, the precipitation amount of inhibitor was reduced. The higher the degree of static recrystallization, the more obvious the effect of rare earth on the precipitation of inhibitor.

In this work, Sm5Mg41 fabricated by vacuum induction melting was milled to greatly improve the hydrogen storage performances. The alloy has higher surface activity and better hydrogen absorption and desorption properties due to the abundant of crystal defects causing by ball milling. Prolonging the time of milling generates the gradual evolution of microstructure of Sm5Mg41 alloy from polycrystalline to nanocrystalline as well as amorphous phase. The phase content of nanocrystalline rises firstly and then reduces with the milling time ascending. When milling for 10 h, the milled alloy consists mainly of nanocrystalline phase with many sub-grain boundaries and a small amount of amorphous below 2 nm. Further extending the milling time causes to the reducing of nanocrystalline phase content and the increasing of amorphous phase content. When the ball milling time was 5, 10, 20 and 30 h, the activation energies of dehydrogenation for the Sm5Mg41 ball milled alloy are 128.2, 112.9, 125.9, and 126.9 kJ/mol H-2, respectively, suggesting that ball milling can change the energy barrier of dehydrogenation reaction. The nanocrystalline grain boundaries introduced by milling provide more channels for hydrogen diffusion, thereby enhancing the hydrogen storage kinetics of the as-milled Sm5Mg41 alloy. The hydrogenation enthalpy changes (Delta H-ab) were-82.387,-77.516,-79.001, and -80.076 kJ/mol H-2, respectively. It is suggested that the thermodynamic stability of the as-milled Sm5Mg41 alloy is weakly reduced by ball milling. The Sm5Mg41 alloy milled for 10 h has the best hydrogen storage property. It can reversible absorb/desorb hydrogen 4.9 wt.% within 0.5 h at 300 degrees C.

借助OM、激光共聚焦显微镜、质谱仪和电解萃取等设备和方法,研究了添加微量稀土 La(质量分数0.001 1％)的取向硅钢在轧制前采用不同加热保温时间对抑制剂固溶行为的影响.结果表明:当稀土取向硅钢在1 250℃分别保温10、20、30 min后,试验钢晶粒尺寸随保温时间延长有先快后慢的长大趋势;三种抑制剂元素Mn、Cu和A1均发生固溶,保温时间对Mn和Cu两种元素的固溶影响明显,固溶量分别由69.8％和43.7％增加至84.2％和85.2％;随着保温时间的延长,稀土取向硅钢中抑制剂的小尺寸未溶物逐渐减少直至消失,较大尺寸未溶物(300～600 nm)逐渐转变为小尺寸未溶物逐步溶入基体中,数量减少且未溶物的类型由复杂逐渐转变为单一.

Electrochemical behavior of Al86Ce10TM4 (TM=Fe, Co, Ni and Cu) amorphous alloys was studied. The amorphous alloys exhibit corrosion resistance and mechanical hardness substantially higher than the traditional Al alloys on merit of electrochemical homogeneity, self-passivating and lattice strengthening of the amorphous matrix. Annealing crystallization of the amorphous alloys can furthermore promote these properties significantly due to the added effect of metallic nano-crystals tessellated in the amorphous matrix in mechanisms of anti-corrosion enhancement and precipitate hardening. The oxide films grown on the amorphous alloys at 630°C in static air provide superior corrosion resistance due to the resilient blockage of the oxide layers to the environment. The results manifest amorphous Al86Ce10TM4 (TM=Fe, Co, Ni and Cu) alloys present distinguished electrochemical and mechanical properties and thus have potential aerospace and defence applications in terms of their mechanical strength (800~1200 MPa), high temperature endurance (300~420°C and anti-oxidation (630°C) and corrosion resistance (10-6~10-8 A/cm2).