Zn-0.45Mn alloy was prepared by melt casting and hot extrusion, and the creep behavior of Zn-0.45Mn alloy was investigated at the temperature range of 37-121 ^oC and by stress in the range of 40 MPa to 170 MPa. Under the low stress condition of 40 MPa, the creep characteristics of Zn-0.45Mn alloy showed creep stress exponent of 5.44, 5.08, and 4.33, corresponding to test temperature at 37 ^oC, 51 ^oC and 121 ^oC respectively. The apparent creep activation energy was calculated to be 24.1-42.1 kJ/mol. In combination with microstructural analysis, the grain boundary slippage may be the main creep mechanism, especially at high temperatures. The results not only reveal the creep behavior of Zn-0.45Mn alloy, but also provide a scientific basis for expanding their potential in biomedical applications.

Inclusions can be easily introduced into steels during smelting, and they have an important impact on the fatigue cracking behavior and fatigue strength of the steels. As the strength of the steel increases, its sensitivity to microstructural defects also increases, yet the fatigue strength does not necessarily increase monotonically. Here, the high-cycle fatigue properties of a newly-developed ultra-high-strength medium-Mn steel with tensile strength higher than 2 GPa were investigated. The morphology, phase composition, distribution and size of the inclusions on the fatigue fracture were observed and analyzed by means of X-ray diffraction and scanning electron microscopy. The results indicate that the high-cycle fatigue of the ultra-high-strength steel is caused by the initiation of cracks at inclusions, which exhibit three types: surface inclusions, subsurface inclusions, and internal inclusions. The fatigue life increases as the crack initiation sites changing from surface to internal inclusions. The fatigue properties of ultra-high-strength steel are extremely sensitive to the size of inclusions. The critical size of the inclusions gradually increases as the distance between the inclusions and the test specimen surface increases. Under the same stress amplitude, the fatigue life increases with the decrease of the inclusion size. Compared with other medium- and high-strength steels, the current steel has high fatigue strength and fatigue ratio, which can be attributed to its high strength and good plasticity. The gradual transformation induced plasticity effect helped to disperse local stress concentration and dissipate plastic work to retard growth of fatigue cracks. Consequently, larger critical inclusion sizes are required for crack initiation and propagation during fatigue.

Spinodal decomposition enables the formation of continuous nanoscale dual-phase structures with periodic compositional fluctuations, a unique microstructure that significantly enhances mechanical properties such as strength, hardness, and creep resistance of alloys. Consequently, tailoring spinodal decomposition to optimize mechanical performance has emerged as a central objective in materials research. While compositional control is vital to this process, and elemental doping provides a precise strategy to regulate the decomposition behavior, the mechanism related with interactions between dopants and spinodal dynamics remains elusive. In this study, the evolution of nanoscale lamellar microstructures in Hf-doped TiSc alloys (0-10% Hf, in atomic fraction) was systematically investigated by using transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray diffraction (XRD), as well as Vickers hardness measurements. The results demonstrate that with the increase of Hf content from 0 to 10%, the lamellar structure width formed by spinodal decomposition in TiSc alloys exhibits a progressive growth trend. Meanwhile, the spinodal decomposition structures of α-Ti and α-Sc undergo morphological transitions from lamellar to interconnected network and blocky morphologies, respectively. The former phenomenon may be attributed to that both the chemical driving force for spinodal decomposition and the lattice mismatch between Ti and Sc atoms may be reduced by the addition of Hf, which may thermodynamically facilitate the occurrence of larger-scale compositional fluctuations within the system, as a consequence, the lamellar width of spinodal decomposition structures is then increased. The latter transformation may be raised from the homogeneous solid solution of low-diffusivity Hf atoms in the TiSc matrix, which significantly decreases the overall diffusion rate of the system, thereby promoting structural evolution in both α-Ti and α-Sc spinodal decomposition phases. Furthermore, the Vickers hardness continuously decreases from 375.37HV to 281.11HV with the widening of lamellar structures, indicating that Hf addition alters the microstructural characteristics and consequently affects the mechanical properties of TiSc alloys.

The 7% B₄C/AlSi10Mg (mass fraction) composite was fabricated using laser powder bed fusion (LPBF) technology. The process parameters such as laser power and scanning speed were optimized. The influence of line energy density on density, microstructure, mechanical properties, and thermophysical characteristics of the acquired composite was assessed. Results indicate that with the rising line energy density, the density of the composite increases initially then decreases, reaching peak value of 97% by 196.4 J/m. High-temperature diffusion of C and B elements from micron-sized B₄C particles induced interfacial reactions, generating the in-situ formation of Al₃BC, AlB₂ phases, and trace Al₄C₃ phases. The acquired composite exhibited room-temperature tensile strength of ~487 MPa, micro-Vickers hardness of ~192HV, specific stiffness of 31.81 m²/s², and thermal expansion coefficient ranging from 11.9 × 10^-6/°C to 21.1 × 10^-6/^oC between 22-400 ^oC. The average thermal conductivity measured as 107.6 W·m^-1·K^-1. The high specific stiffness and low thermal expansion coefficient of this composite make it suitable for manufacturing space optical-mechanical structural components.

Although the direct reduction of iron ore with hydrogen is regared as an important technological approach for the steel industry to achieve low-carbon development, it shows great potential in reducing energy consumption and enhancing efficiency. However, its application in industry is limited by certain deficiencies in its process theory in the presence. The structural evolution of iron ore pellets during the hydrogen metallurgy process can be changed by adjusting process parameters such as ironmaking temperature, which will impact the reduction behavior as a whole. To uncover the microscopic mechanisms related with the effect of temperature on the process of direct reduction iron-making, therefore, the pure hydrogen reduction of iron ore pellets at 600 ^oC to 900 ^oC was examined in terms of the reduction thermodynamics and microstructural evolution of pellets. The findings reveal that, thermodynamically, the Fe₂O₃→Fe₃O₄ reaction stage required substantially lower demand for the diffusion to of the reducing agent H₂ and the diffusion away of the reaction product H₂O in contrast to the Fe₃O₄→FeO and FeO→Fe reaction stages. Increasing the temperature can improve the overall reduction degree of the pellets by strengthening the thermodynamic driving force for the Fe₃O₄→FeO and FeO→Fe stages. The number and size of pores in the pellets increase with temperature, which improves the diffusion driving force and shortens the diffusion channel for the reduction reaction. The nucleation and growth of Fe exhibit distinct characteristics as the temperature increases from 800 ^oC to 900 ^oC, but the reduction efficiency shows only a slight enhancement. This work is important for optimizing the process of hydrogen direct reduction of iron ore pellets, from a theoretical and practical standpoint.

ZnS transparent ceramics with free wurtzite phase α-ZnS were successfully prepared through hot-pressing sintering by 30 MPa at 830 ^oC, using the as-synthesized β-ZnS nanopowders and KX (X = Br, I, Cl) as raw material. It was found that halides KX, as the additives, play the crucial role in the sintering process of ZnS transparent ceramics. Both halides KBr and KI not only promote the rapid growth of grain by generating a liquid phase, but also effectively inhibit the size-induced low-temperature phase transition of the nanopowder cubic phase β-ZnS to the hexagonal one. However, KCl promotes the formation of α-ZnS with an adverse impact on ZnS transparent ceramics. A mechanism of alkali metal halides KX inhibiting the size-induced low-temperature phase transition of ZnS nanoparticles was rationally proposed by combining X-ray diffraction results, microstructure, composition distribution and photoluminescence spectra of ZnS ceramics with the ionic radii of Br^-, I^-, and Cl^-.

Quasi-solid-state electrolytes have garnered significant attention in lithium-ion battery research due to their potential to overcome the safety risks of liquid electrolytes and the low room-temperature ionic conductivity of solid-state electrolytes. In this work, a novel series of quasi-solid-state electrolytes named PHCN (namely PHCN-1, PHCN-2, PHCN-3, and PHCN-4) was fabricated by incorporating mesoporous spherical g-C₃N₄ into a poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) matrix. The resulting PHCN electrolytes feature unique stationary and "instantaneous" structures, which contribute to enhanced ionic conductivity and reduced polymer crystallinity. The optimized sample, PHCN-3 (with 3% g-C₃N₄), exhibits outstanding performance: an ionic conductivity of 2.62 × 10^-3 S·cm^-1 at 30 ^oC, a Li⁺ transference number of 0.71, and a widened electrochemical stability window of approximately 4.6 V. A lithium symmetric cell employing the PHCN-3 electrolyte demonstrated exceptional cycling stability for over 2000 h at a current density of 0.2 mA·cm^-2. Furthermore, a LiFePO₄/PHCN-3-LiPF₆/Li cell maintained a high capacity retention of 88.33% after 200 cycles at a 0.5C rate. These findings indicate that the PHCN quasi-solid-state electrolytes present a promising path for the development of high-performance and safe lithium-ion batteries.

Herewith, the indentation creep of Sanicro25 steel was assessed via an indentation creep test set with a flat-ended cylindrical indenter of 1 mm in diameter in temperature range of 973-1073 K, and stress range of 273-765 MPa. The results show that: with the increase of temperature and stress, the steady state creep rate is increasing; according to the steady state power relationship, the average stress index is deduced to be 3.6, and the activation energy 257-295 kJ/mol, which are in good agreement with those acquired from the uniaxial tensile test. It follows that the indentation creep test can reliably characterize the creep behavior of alloys. The surface of the tested steel presents typical characteristics of plastic deformation accumulation, which may be ascribed to the material flow that occurs beneath the pressure indenter in the fully plastic region along the axial direction; There existed three characteristic deformation zones beneath the indenter, in one of the three zones, the grains exhibit significant preferential orientation deformation, which verified the creep mechanism dominated by dislocation migration.

A multi-component high-entropy alloy Fe₄₀Cr₃₇Ni₂₀Al₃ was melted via vacuum arc melting and casting, which then was subjected to cold rolling and annealing so that to control and adjust its microstructure. Then the microstructure evolution and mechanical properties of the alloy were systematically investigated. The results demonstrate that the as-cast alloy exhibits a dual-phase structure comprising BCC and FCC phases. After cold rolling and annealing, the alloy develops a dual-phasic heterogeneous structure, wherein the BCC phase transforms into a "hard-encapsulated-soft" structure and the FCC phase evolves into a "mixed-grain" structure. This microstructural modification enables a synergistic enhancement in strength and ductility of the alloy. The improvement in ductility is primarily attributed to the enhanced deformability of the BCC phase facilitated by the "hard-encapsulated-soft" structure, while the increase in strength is predominantly ascribed to the hetero-deformation-induced (HDI) strengthening effect and microstructural refinement resulting from the dual-morphology heterogeneous structure.