Preparing heterogeneous composite spherical powders with significant melting point differences and immiscibility properties, which can be used in fields such as additive manufacturing and injection molding, is a key challenge. In this work, a rational powder metallurgy-assisted rotating electrode atomization strategy was developed to synthesize Mo70Cu30 pseudo-alloy spherical powders with well-controlled morphology and microstructure. A dense Mo-Cu rod precursor, prepared via infiltration of 5-10 & micro;m molybdenum and copper powders, enabled stable atomization and droplet formation under optimized conditions. The resulting powders exhibited an exceptionally high sphericity (approximate to 99.5%) and particle size distribution in the range of 40-100 & micro;m. Microstructural characterization revealed a homogeneous spatial distribution of Mo and Cu phases, accompanied by the formation of a Cu3Mo intermetallic phase, indicative of non-equilibrium interfacial reactions during rapid solidification. The powders further demonstrated excellent flowability, high apparent density, and low oxygen content. Mechanistic analysis of the spheroidization process elucidated the interplay between droplet dynamics, phase evolution, and solidification behavior in immiscible, high-melting-point-difference systems. This work establishes a generalizable pathway for engineering heterogeneous pseudo-alloy spherical powders.

Pipeline materials for hydrogen transport must achieve a synergistic balance of mechanical strength, flame retardancy, antistatic performance, and hydrogen barrier capability; however, realizing this combination in practice remains a significant challenge. In this study, a wire mesh reinforced high-density polyethylene (HDPE) composite with a sandwich architecture was designed and fabricated. Magnesium hydroxide, zinc borate, and carbon black were co-milled with a KH560 silane coupling agent to produce a uniformly dispersed slurry, which was subsequently used to coat blended HDPE and ethylene–octene copolymer (POE) granules. The coated granules were laminated with iron wire mesh modified via KH560 surface treatment, followed by hot pressing to construct a PEc/Fe/PEc sandwich composite. The iron wire mesh formed a strong interfacial interaction with the polymer matrix, while the inorganic fillers were homogeneously distributed within the composite. The resulting material exhibited a high tensile strength of 36.31 MPa, an impact strength of 50.75 J/mm2, a Shore hardness of 75 HD, and a volume resistivity of 2.96 × 109 Ω· cm, indicating a favourable balance of mechanical and antistatic properties. Thermal analysis showed an initial decomposition temperature of 415.30 °C, a char residue of 15.00 wt.%, and a peak heat release rate of 500.611 kW·m-2, confirming enhanced flame-retardant performance. In addition, the composite demonstrates a low hydrogen permeability of 5.66 × 10-16 mol· m/(m2·s·Pa), highlighting its excellent barrier capability. The proposed sandwich-structured composite provides a promising material design strategy for hydrogen transport pipelines, achieving a synergistic integration of mechanical robustness, flame retardancy, antistatic behavior, and hydrogen impermeability.

Distinct pore morphologies are often observed in freeze-dried porous materials even under identical freezing conditions, which cannot be fully explained by classical ice-front–particle interaction models. In this work, the role of particle sedimentation during unidirectional freeze-drying is reexamined from a dynamic competition perspective. Based on a force balance analysis incorporating an effective viscous resistance, particle motion in concentrated suspensions is characterized by an effective terminal settling velocity. By comparing the characteristic time scales of particle sedimentation and ice-front propagation, a dimensionless sedimentation–freezing competition parameter, K = V_t /V_f is proposed. When K ≫ 0.1 , particles are able to undergo sufficient rearrangement prior to solidification, favoring the formation of well-aligned lamellar structures. In contrast, when K0.3em < 0.1 , particle motion is increasingly constrained by the advancing freezing front, leading to interface-dominated trapping, lamellar distortion, and interlamellar bridging. Experimental observations in SiO2, Mo, and W freeze-dried systems, spanning a wide range of particle densities, are consistent with the predicted trend of the proposed competition framework. The present approach provides a physically transparent and practical guideline for understanding and regulating microstructural evolution in freeze-dried porous materials.

This study investigated corrosion performance of titanium-steel composite (TA2/Q345) pipes (fabricated via hot assembly and diffusion welding processes) in a simulated marine environment and elucidated their electrochemical coupling and superior corrosion resistances. Results indicated that there was a significant potential difference between TA2 and Q345 which could lead to electrochemical coupling corrosion; however, an interfacial structure comprising a TiC/FeTi/Fe2Ti transition layer and a TiO2 passivation film was formed at the interfaces, which can delay the corrosion process. The charge transfer resistance (Rct) on the titanium side reached a value of 5927 Omega & centerdot;cm2, and the corrosion current density was reduced to 1.16 & times; 10-5 mu A & centerdot;cm-2, effectively preventing corrosion initiation on the titanium surface. The galvanic corrosion rate on the steel side was increased by only 8.3%. Compared to that of bare Q345 steel, the composite pipe exhibited a 5% higher Rct value and a 6% lower corrosion current density. Such the synergistic enhancement is attributed to the transition layer and passivation film which jointly inhibit electrochemical coupling corrosion, which provides great potentials for the titanium-steel composite pipes applied in fields such as marine engineering, energy transportation, and chemical equipment.

Addressing the current issues of insufficient thermal conductivity and low heat dissipation efficiency in electronic packaging materials,the copper-diamond composites were prepared with three different methods,namely,traditional powder metallurgy(PM),stirring friction processing(FSP),and spark plasma sintering(SPS),the microstructure,relative density,interfacial state,and thermal conductivity were comparatively analyzed.The results show that the copper-diamond composites with 50％diamond(volume fraction)prepared by SPS under the sintering pressure of 30 MPa at the holding temperature of 900 ℃ for 20 min have the best performance with the diamond particles uniformly distributed on the copper matrix.The relative density,thermal conductivity,and coefficient of thermal expansion of the SPS composites is 97.4％,517.04 W·m-1·K-1,and 6.63×10-6 K-1,respectively,and there is a transition layer with a thickness of less than 1 μm at the interface,which shows good bonding quality.The performance of the copper-diamond composites prepared by PM is the second,and that of the composites prepared by FSP is the worst.

Hydrogen transportation is one of the critical links for hydrogen energy applications and has commonly achieved via cost-efficient metal pipelines, which are severely hampered by their complex manufacturing processes and susceptibility to hydrogen embrittlement in hydrogen-containing environments. Polyethylene (PE) as a promising alternative has its attributes such as light weight, good flexibility, simplified manufacturing/connection processes, and low cost, but it has inadequate mechanical properties and significant hydrogen permeation and leakage problem. To address these issues, in this study, we developed tri-layer laminated composites using high-density polyethylene (HDPE) and carbon fiber (CF) mesh. A polyethylene composite (PEC) was synthesized using nanofillers in combination with a slurry coating technique. The CFs were harnessed as a reinforcement layer in a PE matrix to enhance the composite's tensile strength and impact resistance. The PEC/CF/PEC triple-layer structure enhanced the mechanical reinforcement from the CFs, effectively retarded the gas permeation, and formed the hydrogen barrier. Results showed that the fabricated laminated composites exhibited strong interfacial bonding and uniform distribution of the fillers and CFs within the HDPE matrix, and significantly improved physical, mechanical and electrical properties. Compared to those of pure HDPE, the PEC/CF/PEC composites demonstrated significantly reduced hydrogen permeability and flame retardancy, suitable for applications such as hydrogen storage tanks, long-distance hydrogen pipelines, or firefighting equipment.

To address poor composition-property matching and high cost limiting AuAgCu alloy applications, this study uses vacuum melting, directional solidification and drawing to fabricate low-gold Au30Ag40Cu30 alloy, systematically investigating its microstructural evolution and properties under different processing conditions. The results indicate that the as-cast alloy consists of a needle-like Ag-rich phase and block-shaped AuCu phase, which form a coherent interface. Following directional solidification, grain growth occurs preferentially along the <111> orientation, resulting in refined grains and a reduction in transverse grain boundaries. After drawing deformation, a fibrous microstructure is developed, further grain refinement is achieved, and dislocation density increases significantly. The tensile strengths of the alloy in the as-cast, directionally solidified, and drawn states are 553.6 MPa, 707.3 MPa, and 768.58 MPa, respectively, while the corresponding electrical conductivities are 8.0 x 10(6) S/m, 9.76 x 10(6) S/m, and 5.93 x 10(6) S/m, respectively. The improved synergy between mechanical and electrical properties arises from the fibrous Ag-rich phase facilitating electron transport and the dispersed AuCu phase contributing to precipitation strengthening. This also ensures that the Au30Ag40Cu30 alloy wire exhibits low signal transmission loss, short time delay, and high accuracy at frequencies below 3 GHz.

Aiming at the problems of low specific strength and specific modulus of Al-Si alloys, Ti5Si3 reinforced aluminum matrix composites (AMCs) were prepared by using Al-Si-Ti as in-situ composite system via powder metallurgy method below Al-Si eutectic temperature. The microstructure evolution of in-situ reinforcements and its influence on the mechanical performance of AMCs are systemically investigated by controlling Ti-Si interdiffusion reaction process. The results show that Ti5Si3 reinforcements are in-situ synthesized in AMCs. As the holding time extends, the in-situ formed reinforcements gradually transform from Ti5Si3@Ti core-shell structure to Ti5Si3 nano cluster particles due to Ti core is progressively being completely consumed. However, AMCs exhibit a better strength-ductility matching when Ti5Si3@Ti core-shell structure reinforcements are retained due to its excellent crack passivation ability, especially the thickness ratio of Ti core radius to Ti5Si3 shell reaches 1.27. By forming a coherent/semi-coherent composite interface of Al/TiSi/Ti5Si3, making Ti5Si3 nano particles exhibit good interface bonding with Al matrix, which enables the strengthening effect can be fully exerted and effectively reduces the stress concentration. Under the combined effect of dispersion strengthening, grain refining strengthening, dislocation strengthening and load transfer strengthening, Ti5Si3 nano clusters reinforced AMCs show the highest tensile strength of 367 MPa while maintaining a good elongation of 6.5%. As the holding time is further extended to 120 min, the defects appeared in the matrix, leading to premature failure during loading and decline in performance for AMCs.

When titanium-based hydrogen storage materials are employed in hydrogen transportation and portable energy storage systems, they face challenges such as limited hydrogen storage capacity, sluggish hydrogen absorption and desorption kinetics, and high residual hydrogen content. To tackle these problems, herein, a synergistic enhancement strategy was proposed to alloy titanium with elements of V (which can regulate phase structure and enhance hydrogen storage capacity) and Ni (which can improve hydrogen absorption/desorption kinetics) via a vacuum suspension melting process, followed with the controlled heat treatment processes. The obtained alloys were consisted of Ti-V and Ti-Ni phases. Under a hydrogen activation temperature of 313 K and a hydrogen pressure of 4 MPa, various types of hydrides were formed in the alloys including TiH2, VH2, and Ti2NiH0.5. Among all the prepared alloys, the Ti60V34Ni6 alloy exhibited the highest hydrogen storage capacity, reaching 2.1 wt% in the as-cast state and 2.4 wt% after annealing. The dehydrogenation activation energy was found to decrease from 122.3 kJ/mol in the as-cast state to 89.4 kJ/mol after annealing. Meanwhile, the hydrogen absorption rate was increased from 1.25 wt% min(-1) to 2.17 wt% min(-1) after annealing. The as-cast Ti60V34Ni6 alloy exhibited a good poisoning resistance. Post annealing of TiVNi alloys enhanced formation of more ordered grains and hydrogen storage channels, which facilitated hydrogen diffusion, increased the number of available sites for hydrogen occupation, and enhanced overall hydrogen storage capacity of the alloys.

Preparing heterogeneous composite spherical powders with significant melting point differences and immiscibility properties, which can be used in fields such as additive manufacturing and injection molding, is a key challenge. In this work, a rational powder metallurgy-assisted rotating electrode atomization strategy was developed to synthesize Mo70Cu30 pseudo-alloy spherical powders with well-controlled morphology and microstructure. A dense MoCu rod precursor, prepared via infiltration of 5–10 μm molybdenum and copper powders, enabled stable atomization and droplet formation under optimized conditions. The resulting powders exhibited an exceptionally high sphericity (≈99.5%) and particle size distribution in the range of 40–100 μm. Microstructural characterization revealed a homogeneous spatial distribution of Mo and Cu phases, accompanied by the formation of a Cu3Mo intermetallic phase, indicative of non-equilibrium interfacial reactions during rapid solidification. The powders further demonstrated excellent flowability, high apparent density, and low oxygen content. Mechanistic analysis of the spheroidization process elucidated the interplay between droplet dynamics, phase evolution, and solidification behavior in immiscible, high-melting-point-difference systems. This work establishes a generalizable pathway for engineering heterogeneous pseudo-alloy spherical powders.

To tackle key issues of inhomogeneous microstructure distribution, poor thermal conductivity, and relatively high thermal expansion coefficient of molybdenum-copper (MoCu) composites for electronic and engineering applications, in this study, heterogeneous MoCu composites were prepared using integrated freeze-drying and infiltration methods. With water used as the major solvent, molybdenum skeletons with different solid contents were successfully obtained using the freeze-drying method operated at -70 degrees C. Porous structures of the skeletons with an average pore diameter of similar to 5 mu m were isotropically and uniformly distributed in all directions, and the obtained compressive strengths of these skeletons were ranged from similar to 149 to similar to 232 MPa. After post-infiltration with copper at 1350 degrees C, the synthesized composites exhibited evenly distributed copper and molybdenum phases, achieving a high thermal conductivity of up to similar to 235.2 W/(mK) and a low thermal expansion coefficient of 6.1 x 10(-6)/degrees C. The intrinsic mechanisms underlying the high thermal conductivity and low coefficient of thermal expansion in MoCu composites were attributed to the formation of a relatively dense and interpenetrating network structure between the Mo and Cu phases, and an appropriate level of porosity effectively compensated for certain deformations induced by thermal expansion and contraction during temperature variations.

The long-period stacking ordered (LPSO) phase in magnesium alloys has attracted considerable attention for its potential to enhance both mechanical properties and hydrogen storage performance. In this study, Mg–Ni–Ce alloys were fabricated using arc melting and melt-spinning techniques to examine the effect of cooling rate on microstructural evolution and LPSO phase formation. The results show that the LPSO phase forms in the melt-spun alloy but is absent in the arc-melted counterpart. The rapid cooling rate during melt spinning suppresses atomic diffusion, thereby inhibiting the formation of equilibrium phases and promoting solute segregation at grain boundaries. This solute enrichment induces lattice distortion and defect generation, which in turn facilitates the nucleation of single-unit LPSO structures. Although the presence of the LPSO phase markedly enhances the mechanical strength of the alloy, it has a negligible impact on hydrogen storage performance.

Diamond/copper composites are recently explored extensively for their exceptional thermal conductivity and low coefficient of thermal expansion. However, there are significant challenges because of poor interfacial wettability and phonon mismatch between diamond and copper matrix, which contribute to high interfacial thermal resistance and a significant discrepancy between the actual and theoretical thermal conductivity of these composites. To tackle these issues, this study employed a salt bath plating technique to deposit a tungsten layer on diamond surfaces, and then diamond/copper composites were fabricated using spark plasma sintering. Results showed that an in-situ reaction occurred at the interface between the tungsten coating and diamond, forming a tungsten carbide transition layer, which effectively reduces interfacial thermal resistance and suppresses diamond graphitization during high-temperature sintering. The synthesized diamond/copper composite achieved a maximum relative density of 97.7 %, a thermal conductivity of 611.92 W/(m center dot K), and a coefficient of thermal expansion of 7.24 x 10-6 K-1. The good thermal conduction in the diamond/copper composites is attributed to the improved interfacial bonding, enhanced electron conduction in the copper matrix, minimized energy dissipation and enhanced phonon conduction, and improved interfacial heat transfer.

To address key issues of TiFe-based hydrogen storage alloys such as poor hydrogen storage capacity, difficulties in activation, and slow hydrogen absorption/desorption kinetics, this paper develops a novel strategy to incorporate Mn and La elements into TiFe alloys via an arc melting process. Before hydrogenation, the original Ti1.2Fe alloy was primarily consisted of TiFe and beta-Ti, which were transformed into TiH2 after hydrogen absorption. However, after addition of 9 at.% of Mn, the Ti-rich phase was transformed into TiMn2 (a Laves phase), and further into TiMn2Hx after the hydrogenation process. Further alloying with a trace amount of La led to the formation of LaH2 after hydrogenation. Under hydrogenation conditions of 40 degrees C and 4 MPa, the hydrogen storage capacities of Ti1.2Fe, Ti1.2Fe0.8Mn0.2, and Ti1.2Fe0.8Mn0.2La0.008 alloys were 1.56 wt%, 1.78 wt%, and 2.05 wt%, exceeding the TiFe(1:1) alloy theoretical value of 1.86 wt%. The hydrogen absorption/desorption rate was increased from 1.29 wt%.min(-1) to 1.66 wt%.min(-1), and the activation energy for hydrogen desorption was decreased from 45.61 kJ/mol (Ti1.2Fe) to 26.45 kJ/mol (Ti1.2Fe0.8Mn0.2La0.008), respectively. Both the beta-Ti and TiMn2 provided effective pathways for hydrogen's transport into TiFe. Meanwhile, La not only provided additional diffusion pathways but also acted as a sacrificial element to suppress further oxidation of the material, thus enhancing the hydrogen storage performance of the TiFe-based alloy.

To address the issues of low friction coefficient,poor stability,and high wear of the traditional copper-based brake pads under high-temperature braking conditions,the copper-based brake pads were prepared by high temperature solid-phase hot-pressing sintering at 880℃after the cold pressing forming of the mixed components,using Cu‒Fe as the main components,Ni and Sn as the strengthening elements,graphite and MoS2 as the lubricating components,and mullite,SiC,and zircon sand as the friction components.The phase composition,friction performance,hardness,density,and morphology of the prepared copper-based brake pads were investigated by X-ray diffractometer,high-temperature friction and wear testing machine,Archimedes displacement method,scanning electron microscope,and energy spectrometer.In the results,the wear rate of the prepared copper-based brake pads is 2.9 mg·(N·m)‒1,the friction coefficient is 0.34～0.41,and the microstructure is fine and evenly distributed with the stable high-temperature performance.The wear mechanism is composed of abrasion,adhesion,and fatigue wear with the oxidative wear taken place at high temperature.

Porous tungsten is composed of tungsten skeleton with numerous internal pores, and shows high temperature resistance, good corrosion resistance, large specific surface, and high permeability, promising for aviation, electronics, and high temperature manufacture applications. Formation of the highly porous tungsten structures has been a key barrier for its successful applications. In this study, porous tungsten was prepared using a freeze-drying method, and influences of cooling sources’ distributions on microstructures and properties of porous tungsten were investigated. Results showed that the distribution of cold source has significant influences on detailed structures of porous tungsten. Lamellar and porous structures were obtained when the ice crystals were grown in a columnar form. We proposed that shapes and sizes of these porous structures were controlled by a combined effect of ice crystal growth rate and particle sedimentation rate.

In this paper, nano-powders of CeO2 modified rGO(CeO2@rGO) with different mass ratios were prepared using a hydrothermal method with GO and Ce(NO3)3 & sdot;6H2O as the resources. Then, they were added into PAO5w-40 base oil to enhance its tribological properties. Experimental results showed that the synthesized CeO2@rGO has a laminar structure, with spherical CeO2 powders uniformly grafted onto the surface of graphene. The dispersion stability of the lubricating oil was enhanced by adding the CeO2@rGO composites, and it also increased with the proportion of CeO2 in the composite powders. When the CeO2:rGO composite nanopowders with a weight ratio of 3:1 were added, the dispersion stability of the lubricating oil showed the best performance. Its viscosity was slightly lower than that of the base oil, with a Zeta potential of 33.805 mV. Compared with the lubricating oil, the friction coefficients of the lubricating oil with the added nanocomposites were reduced by 31.9 %, and the wear depth and wear volume were reduced by 58.3 % and 83.3 %, respectively. Such excellent lubrication performance was mainly attributed to the effective barrier formed between the friction pairs of the nanocompositeenhanced lubricating oil, and the uniformly dispersed nano-powders in the lubrication film, which played an effective rolling bearing effect between the friction pairs. Under the action of shear forces during wear processes, the rGO produced effective sliding movements among nanocomposite layers, which significantly reduced the friction coefficient and wear volume.