Abstract:Block and Gyroid scaffold Fe-30Mn alloys were prepared by powder bed fusion with laser beam (PBF-LB) and in-situ alloying, and the effects of different printing parameters on the performance of specimens were studied. Results show that insufficient laser energy input during printing leads to inhomogeneous mixing of iron and manganese, which degrades the properties of the alloy. Excessively high energy input can cause manganese to vaporize, yielding a composition that deviates from the target. With optimized laser parameters, block specimens exhibiting a uniform Fe/Mn distribution can be obtained with an ultimate tensile strength of 644.67 MPa, an elongation of 21.61%, and a corrosion rate of 0.042 mm/a in simulated body fluid. Moreover, the resulting porous scaffold shows a porosity of 49.84%, a yield strength (0.2% offset) of 66.11 MPa, a compressive strength at 20% strain of 170.76 MPa, and an elastic modulus of 6.41 GPa. The results of indirect toxicity tests and cell adhesion tests show that the alloys have good biocompatibility. In conclusion, the Fe-30Mn alloy prepared by PBF-LB in-situ alloying holds promise for biodegradable human bone implants.

Abstract:The microstructure, mechanical properties, corrosion behavior, and cytotoxicity of biodegradable Zn-1.5Sn-xSr alloys (x=0, 0.3, 0.5, wt%) were investigated. The results indicate that the addition of Sr introduces minor SrZn₁₃ phases, enhancing the yield strength and elastic modulus of the Zn-1.5Sn-xSr alloys. Transmission electron microscopy analysis reveals the existence of the SrZn₁₃ phase through the calibration of diffraction spots. Electrochemical tests confirm the formation of a passive film on Zn-1.5Sn-xSr alloys, with Zn-1.5Sn-0.3Sr alloy exhibiting higher corrosion resistance. Further immersion tests and X-ray photoelectron spectroscopy analysis elucidate the elemental composition and content of the passive film formed by the corrosion products, which primarily consists of oxides, hydroxides, and slightly soluble carbonates and phosphates. In terms of cytotoxicity, the Zn-1.5Sn-xSr alloys exhibit excellent biocompatibility. MTT experiments show that the cell viability can reach up to 130%, which is attributed to the release of Sr²⁺ during the degradation. Sr²⁺ and Zn²⁺ ions jointly promote the cell proliferation and differentiation.

Abstract:Ceramic coatings were prepared on 2195 Al-Li alloy by micro-arc oxidation (MAO) in a silicate-phosphate electrolyte solution under different current densities. The effect of current density varying from 200 A/m² to 800 A/m² on the microstructure, corrosion resistance, and wear resistance of MAO coatings was investigated. The surface and cross-sectional morphologies, composition, and roughness of MAO coatings were analyzed by scanning electron microscope, energy disperse spectrometer, X-ray diffractometer, X-ray photoelectron spectroscope, and surface roughness tester. The results show that with the increase in current density, the roughness and thickness of MAO coating increase. MAO coatings are mainly composed of γ-Al₂O₃ and a small amount of α-Al₂O₃. MAO coatings prepared under the maximum current density is the densest. Potentiodynamic polarization tests indicate that the corrosion resistance of coatings increases with the increase in current density. When the current density is 800 A/m², MAO coating exhibits the best corrosion resistance, with a corrosion potential of -0.536 V and a corrosion current density of 4.32×10^-7 A/cm², which is two orders of magnitude lower than that of the substrate. Electrochemical impedance spectroscopy results indicate that, at a current density of 800 A/m², the sample possesses the largest capacitive arc radius and the highest impedance magnitude in the low-frequency region. The wear resistance of MAO coatings increases with the increase in current density. When the current density is 200 A/m², the wear mechanism is dominated by abrasive wear. With further increase in current density, the wear mechanism remains abrasive wear. MAO coatings prepared at 800 A/m² show the best wear resistance with a wear rate of 1.355×10^-4 mm³/(N?m).

Abstract:This study optimized the previously established low-pressure chemical vapor deposition (CVD) model for tungsten, enabling its application under atmospheric pressure conditions to deposit high-performance coatings on the surface of rocket engine throat liners. The effects of three distinct reactor configurations, including a straight-tube inlet, an integrated gas distribution device, and a combination of a distribution device with a flow guide baffle, on the flow dynamics, thermal field, species concentration, and deposition kinetics of reactors were investigated. Numerical and experimental results demonstrate that the configuration incorporating both a distribution device and a baffle eliminates vortices within the liner region by promoting radial gas diffusion, thereby significantly improving flow field uniformity. This optimized design not only improves the uniformity of the deposition rate on the throat insert, but also slightly enhances the service efficiency of tungsten hexafluoride. This work provides a theoretical foundation for designing CVD systems for highly uniform tungsten coatings and offers a practical solution for their engineering application.

Abstract:The corrosion behavior of unoxidized and pre-oxidized 56Cu-22Ni-12Fe-8Al-2La anode alloys was investigated in a Na₃AlF₆-K₃AlF₆-AlF₃-Al₂O₃ electrolyte for aluminum electrolysis at 800 °C. Electrochemical tests of the metal anodes in molten salt for aluminum electrolysis were conducted, and the corrosion mechanism of the alloys was investigated. Results show that the oxide layer formed on the pre-oxidized alloy at 800 °C in an O₂ atmosphere mainly consists of oxides of aluminum, nickel, iron, copper, and lanthanum. After aluminum electrolysis for 3 h, the corrosion products formed on the unoxidized anode alloy demonstrate a tri-layered structure, and the discontinuous and porous oxide layer provides a connected channel during electrolysis, allowing the electrolyte to directly penetrate the metal matrix to a depth of approximately 320 μm. The corrosion oxide layer formed on the pre-oxidized anode alloy is about 190 μm in thickness. The outer and inner oxide layers include continuous Ni-/Fe-/Al-/Cu-rich oxides (mainly NiFe₂O₄ and CuAlO₂). The middle layer, with a thickness of about 15 μm, contains a dense and continuous NiFe₂O₄ layer. A small amount of electrolyte appears in the oxide layer and penetrates into the metal matrix. The pre-oxidized alloy exhibits better corrosion resistance and stability than the unoxidized alloy during aluminum electrolysis.

Abstract:NbTiZrMo_x alloys were prepared by vacuum arc furnace with high-purity powder mixtures of Nb, Ti, Zr, and Mo as raw materials. The role of element Mo in NbTiZrMo_x alloys and the effect of different Mo content on microstructure, microhardness, wear resistance, and corrosion resistance of NbTiZrMo_x alloys were investigated. Results show that these alloys display a typical dendritic morphology with a single-phase body-centered cubic crystal structure. The microhardness and wear resistance of NbTiZrMo_x alloys are significantly improved with the increase in Mo content, which is attributed to solid-solution strengthening and fine-grain strengthening. With the increase in Mo content, the dominant wear mechanism of the alloy transforms from adhesive wear accompanied by abrasive and oxidative wear to oxidative wear with slight adhesive wear. Electrochemical corrosion tests conducted in a 3.5wt% NaCl solution reveal that the corrosion resistance of NbTiZrM alloys exhibits a trend of initial enhancement followed by deterioration as Mo content rises. The alloy containing 14.29at% Mo achieves the optimal corrosion resistance, demonstrating that an appropriate addition of Mo facilitates the formation of a stable passive film and thereby markedly improves the corrosion resistance of the alloy.

Abstract:To address quality issues such as cracking and earing during the thermal deep drawing of TC4 titanium alloy cylindrical parts, an ultrasonic vibration-assisted forming method was proposed. The effects of ultrasonic vibration on the thermal performance and high-temperature interfacial friction behavior of TC4 titanium alloy were studied by ultrasonic vibration-assisted tensile and sliding friction experiments. By analyzing the drawing force, surface quality, wall thickness distribution, and earing morphology of the fixed-dimension blank under different temperature conditions, the influence of ultrasonic vibration on the forming process and forming quality of TC4 cylindrical part was clarified. Finally, through variable-dimension limit drawing experiments under different temperature conditions, the limit drawing coefficient and the effective height of the TC4 cylindrical part assisted by ultrasonic vibration were obtained. The research findings indicate that applying ultrasonic vibration during the thermal deep drawing of TC4 cylindrical parts can not only effectively reduce the drawing force and earing ratio, but also improve the uniformity of wall thickness distribution, significantly enhancing the limiting drawing ratio and effective height of the drawn specimens.

Abstract:The lattice-structured porous Ni-Fe alloys with high porosity (95%?98%) were prepared by electrodeposition coupled with additive manufacturing technique. Two types of lattice-structured models were designed, namely tetrahedral structure and simple cubic. It is found that reducing the strut length or increasing the strut diameter and the inclination angle of struts relative to the horizontal direction significantly enhances the specific surface area of the lattice structures. The influence of electrodeposition parameters on the macroscopic morphology and structural characteristics of the porous Ni-Fe alloys was analyzed. The optimal electrodeposition conditions are determined as follows: cathode current density of 2?3 A·dm^-2, deposition temperature of 50?60 ℃, electrolyte pH of 3, and deposition time of 1 h. Under such condition, both tetrahedral and simple cubic porous Ni-Fe alloys were prepared. The uniaxial quasi-static compression tests demonstrate that the yield strength of the tetrahedral porous Ni-Fe alloy reaches 22.91 MPa, which is 35.8% higher than that of the simple cubic structure. Finite element simulation results indicate that the stress under compressive loading is concentrated in the nodal regions of the alloys with both two lattice structures. The stress concentration is the main cause for the local deformation and fracture.

Abstract:Porous tungsten structures were prepared by fused filament fabrication (FFF). The microstructural evolution at each stage of the FFF process and the final pore characteristics of the sintered tungsten were investigated systematically. The results show that porous tungsten components with tightly bonded layers and no defects are successfully prepared by FFF. The maximum loading of commercial tungsten powder with a particle size of 3 μm reaches 56%, and the compounded feedstock exhibits excellent rheological properties. Furthermore, the influence of printing parameters on the green density was investigated, identifying the optimal combination: the nozzle diameter of 0.6 mm, a layer thickness of 0.1 mm, and the printing speed of 30 mm/s. The porous tungsten prepared by FFF shows a uniform pore distribution. As the sintering temperature increases, the average pore size decreases, the complexity of the pores increases, and the hardness and compressive strength increase.

Abstract:Three types of truss rod unit lattice structures were nested within the honeycomb cavities to obtain a new honeycomb-nested lattice structure. Using AlSi10Mg powder as the material, samples with different relative densities of the new bcc honeycomb-nested lattice structure (HC-N-bcc), honeycomb-nested symmetric rod lattice structure (HC-SP), new fluorite-type honeycomb-nested lattice structure (HC-N-F), and hollow honeycomb structure (HC-E) were fabricated by the selective laser melting (SLM) technique. Lateral compression mechanical properties, macro-micro deformation mechanisms, and energy absorption analyses were conducted on these samples. The results show that the lateral compression performance of the honeycomb-nested lattice structures is significantly superior to that of the hollow honeycomb structure. At the relative density of 46%, the HC-SP structure exhibits a compression modulus and peak stress that are 43% and 44.7% higher than those of HC-E, respectively. Under the strain of 50%, its energy absorption () and crushing force efficiency (CFE) are 7.7 and 5.3 times higher than those of HC-E, respectively. When truss unit lattices are embedded in the honeycomb cavities, the honeycomb shell deforms gradually and uniformly instead of fracturing instantly, significantly improving the compressive stability of the honeycomb structure. Furthermore, the larger the proportion of the truss volume in the overall structure, the better the performance improvement of the honeycomb-nested lattice structure.

Abstract:High-temperature and electro-assisted tensile experiments were conducted on TC4 titanium alloy, with the deformation temperature of 600?900 ℃ and the current density of 14?22 A/mm². The effects of temperature and current density on the flow stress of the alloy were investigated. The experimental results show that during the hot tensile process, the flow stress of the material decreases with the increase in temperature, and the elongation is positively correlated with temperature. The flow stress of the material decreases after applying pulsed current, and the elongation first increases and then decreases with the increase in current density. Finally, based on the true stress-true strain data of tension, a multi-physical field constitutive model coupling thermal and athermal effects was constructed on the basis of the original Johnson-Cook model framework. The constitutive model parameters were determined by the regression fitting method, and error analysis was performed between the experimental and predicted values. The results show that the coefficient of determination R² of the constitutive model is more than 0.95, the mean relative error is less than 2.5%, which indicates that the model has relatively good predictive ability within a wide range of process parameters. The research aims to provide a theoretical basis for the electro-assisted forming of titanium alloys and a reference for optimizing forming process parameters.

Abstract:The hydrogen compatibility of FV520B steel immersed in different hydrogen-blended natural gas environments was evaluated through slow strain-rate tensile testing, fatigue crack propagation testing, and fracture toughness testing and fracture morphology and microstructural characteristic were analyzed. The results show that as the hydrogen blending ratio and gas pressure increase, both the tensile strength and yield strength of FV520B steel decrease in different degrees, and the elongation after fracture and the reduction of area also decrease, demonstrating hydrogen induced plastic loss phenomenon. With increasing hydrogen content and gas pressure, the crack growth rate-stress intensity factor range curves shift left, leading to earlier crack propagation and faster entry into unstable fracture of the sample. Meanwhile, the fracture toughness K_IC value of FV520B steel decreases, and a tendency towards brittleness is observed in the low magnification fracture morphology of the material. The present study provides an important basis for evaluating the engineering application of centrifugal compressor impeller materials during transport of hydrogen-blended natural gas.

Abstract:To address the lack of service performance evaluation of the extruded and forged FGH95 alloy under the service conditions of the aero-engine powder-disc components, a feature-base specimen based on the maximum principal strain gradient on the retaining groove of the powder-disc component were designed according to certain design criteria, and the design method was verified. Then, the fatigue life method based on the theory of critical distance (TCD) was employed to predict the service life. Finally, the fatigue life method and failure mechanisms were validated. The results show that the three-dimensional spatial domain automatic search method proposed in the present study can obtain the maximum principal strain gradient on the retaining groove. Compared with the Morrow-modified total strain life method commonly used in engineering, the TCD-life method incorporating the strain gradient can more accurately predict the fatigue life of the retaining groove. The important reason why the standard notched round bar specimen cannot accurately predict the fatigue life of the retaining groove is reasonably explained. The differences in the fatigue failure mechanisms of the standard notched round bar specimen, retaining groove, and its feature-base specimen are verified by fracture analysis techniques.

Abstract:Micro-motion wear is one of the primary factors limiting the service life of pressure tubes used in heavy-water reactors. To enhance the operational reliability of Zr-2.5Nb pressure tubes for heavy-water reactors. A pre-formed film with thickness of approximately 1 μm on the surface of Zr-2.5Nb alloy by three pre-oxidation treatment processes was prepared, and the relationship between its mechanical properties and microstructure was investigated. The three pre-oxidation treatment processes were conducted at 400 °C for 24 h: (1) in deoxidized superheated steam at 10.3 MPa; (2) in superheated steam with dissolved oxygen of 300 μg/kg; (3) in low-pressure steam at 2 MPa. The results indicate that the Zr-2.5Nb alloy consists of α-Zr and β-Zr phases, with both α-Zr and β-Zr phases exhibiting elongated morphologies. And β-Zr phase continuously distributes at the α-Zr grain boundaries. Microstructures of the films formed under different pre-oxidation conditions exhibit differences. Among them, the pre-formed film prepared under deoxidized conditions contains relatively more microcracks, with shorter and more randomly arranged columnar grains; the pre-formed film prepared under dissolved oxygen conditions is the densest with the fewest defects, while the pre-formed film prepared under low-pressure conditions has the greatest thickness with relatively more pores and cracks. Compared with the original alloy, the pre-formed film increases the nano-hardness of the alloy by 50%–180%, improves the hardness-to-modulus ratio (H/E) by approximately 56%–81%, and reduces the wear rate by 31%–44%. The pre-formed film significantly enhances the surface hardness and wear resistance of the alloy, transforming the wear mechanism from severe abrasive wear to mild adhesive wear. Among three pre-formed films, the pre-formed film prepared under dissolved oxygen conditions is the densest and exhibits the most pronounced hardness enhancement. This is because the strengthening effect of the pre-formed film is closely related to its microstructure. A dense and intact oxide film not only has higher hardness, but also adheres more firmly to the metal substrate, making it less prone to peeling or cracking under localized stress.

Abstract:SiC and graphene nano-platelet (GNP) hybrid reinforced aluminum matrix (GNP/SiC/Al) composites were fabricated by high-energy ball milling combined with powder metallurgy process. The microstructure, mechanical properties, and wear performance of GNP/SiC/Al composites were characterized by SEM, TEM, universal tensile testing machines, and tribometers, with comparative analysis against gray cast iron (HT250). The results indicate that when SiC and GNP are uniformly dispersed in the matrix, the tensile strengths of composites are 287 and 101 MPa at room temperature and 350 ℃, respectively. During room temperature wear tests, the wear resistance of composites is lower than that of HT250. Both materials exhibit adhesive and abrasive wear mechanisms. Under high-temperature wear conditions, the wear resistance of the composites is better than that of HT250. HT250 exhibits adhesive and abrasive wear mechanisms, the composites are mainly characterized by adhesive wear. The exceptional high-temperature wear resistance of GNP/SiC/Al composites is attributed to three primary mechanisms: the high-temperature pinning effect of SiC and GNP; the self-lubricating properties of GNP; the formation of mechanically mixed layers during wear.

Abstract:Trace amounts of Ca and Gd were used for composite alloying, and a large amount of high-melting point Al₂Ca phase, Al₂Gd phase, and Al₈Mn₅ phase were in-situ generated in the microstructure of Mg-8Al-0.4Zn-0.9Ca-0.2Gd-0.2Mn (AZXVM80100, wt%) alloy. Results show that these high-melting point phases can be extruded at a die exit speed of 32.4 m/min without any hot cracks. The excellent extrudability is mainly attributed to the dominant presence of Al₂Ca, Al₂Gd and Al₈Mn₅ phases with high thermal stability, which do not melt despite the substantial amount of deformation heat generated during the high-speed extrusion (32.4 m/min), avoiding hot cracking. Meanwhile, these thermally stable Al₂Ca, Al₂Gd, and Al₈Mn₅ phases exert a remarkable refining effect on the recrystallized grains. Besides, the as-extruded AZXVM80100 alloy displays a fully dynamic recrystallized microstructure. It has a typical basal texture and fine grains with an average grain size of 8.6±1.7 μm. Owing to the significant grain boundary strengthening, the as-extruded AZXVM80100 alloy demonstrates a high tensile yield strength of 257.4±4.1 MPa. Furthermore, the as-extruded AZXVM80100 alloy also exhibits a high elongation of (14.9±0.8)%, which is dominantly coordinated by dislocation slip. The newly developed high-speed extrudable AZXVM80100 alloy, containing large amounts of cheap elements (Al, Zn, Ca, Mn) and trace amounts of rare earth (Gd), has great potential in manufacturing extrusion profiles because of its good strength-ductility synergy.

Abstract:FGH4097 and GH4079 alloys were prepared by powder metallurgy and wrought processes, respectively. The experimental results show that the grain size of FGH4097 superalloy is smaller and has more uniform distribution compared with that of GH4079 superalloy, with the former having a grain size of approximately ASTM grade 6.0 to 6.5 and the latter having a grain size of approximately ASTM grade 4.5 to 5.0. The size of the γ′ strengthening phase in FGH4097 superalloy is larger than that in GH4079 superalloy, with secondary γ′ phase being mostly cubic and having an average size of about 0.48 μm in FGH4097 superalloy, whereas in GH4079 superalloy, the secondary γ′ phase is mainly near-spherical with an average size of about 0.14 μm. Comparing the tensile properties of the two superalloys, the results indicate that under the tensile conditions from room temperature to 750 ℃, the tensile strength of the FGH4097 superalloy is higher than that of the GH4079 superalloy, and its plasticity is also significantly superior to that of the GH4079 superalloy. As the temperature increases, the difference in tensile strength and plasticity between the two superalloys becomes more pronounced. To further explore the high strength and high plastic deformation mechanisms of FGH4097 superalloy during tensile processes at different temperatures, the microstructure of the tensile fractures was characterized by TEM. For the FGH4097 alloy under tensile deformation conditions from room temperature to 650 °C, the dislocation configurations are predominantly characterized by high-density dislocation pile-ups in the γ channels, as well as dislocations cutting the γ′ phase in the form of superlattice stacking faults and antiphase domain boundaries, supplemented by a small number of continuous stacking faults cutting the γ′ and γ phases. This phenomenon indicates that the deformation of the alloy at low to medium temperatures is primarily controlled by dislocations cutting the γ′ phase. As the tensile temperature increases to 750–850 °C, the dislocation configuration in the FGH4097 alloy undergoes a significant transformation. A large number of microtwins form in the γ′ phase and γ matrix, becoming the dominant phase, while continuous stacking faults and superlattice stacking faults play only secondary roles. Under high-temperature conditions, the dominant deformation mechanism of the alloy shifts from dislocation cutting to a synergistic plastic deformation mechanism involving microtwins. For the GH4079 alloy under tensile conditions at 25, 650, and 750 °C, the phenomena of a large number of continuous stacking faults cutting the γ′ and γ phases, a small number of superlattice stacking faults cutting the γ′ phase, and a limited number of microtwins cutting the γ′ and γ phases are observed in GH4079 alloy, which are its primary deformation mechanisms.

Abstract:The cyclic oxidation behavior of a cast ZTNM TiAl alloy at 650 and 750 ℃ in accordance with the HB5258 standard was investigated. The results indicate that the oxidation mass gain kinetics of the alloy at both temperatures follows a parabolic law. The oxidation rate at 650 ℃ (k''= 0.0082 g?m^-2?h^-1) is lower than that at 750 ℃ (k''= 0.0095 g?m^-2?h^-1), with both rates qualified as “complete anti-oxidation” grade. The oxidation process contains three distinct stages: the initial formation of a mixed TiO₂ and Al₂O₃ scale; the development of a continuous TiN/Ti₂AlN nitride layer at the scale/metal substrate interface during the intermediate stage; the formation of an Al-depleted zone within the oxide scale after long-term exposure. The higher temperature (750 ℃) promotes the growth of TiO₂, resulting in a thicker oxide scale. The nitride layer plays a critical role in determining the oxidation rate and the structural stability of the scale.

Abstract:Compositionally graded 15Co-25Cr-(60-x)Fe-xMo (x=0-5, wt%) specimens were fabricated by laser powder bed fusion (LPBF) using blended elemental powders of Co, Cr, Fe, and Mo, employing an in-situ alloying strategy. The compositional homogeneity, phase constitution, and microstructure of the specimens with different Mo contents were investigated. Furthermore, the influence of Mo content on the magnetic properties was elucidated by integrating experimental findings with first-principles calculations. The results indicate that all specimens achieve full alloying without defects such as porosity or un-melted particles. The magnetic properties exhibit a non-monotonic trend with increase in Mo content, initially enhancing before deteriorating. Optimal magnetic performance is obtained at the Mo content of 3wt%, yielding a coercivity () of 26.54 kA/m, a remanence () of 0.9 T, and a maximum energy product () of 11.56 kJ/m³. Additionally, Mo incorporation is found to enhance the microhardness of the alloys, with the 15Co-25Cr-57Fe-3Mo sample exhibiting a hardness of 424HV_0.5.

Abstract:Laser powder bed fusion (LPBF) has emerged as a powerful additive manufacturing technique for fabricating architected cellular metallic structures with precisely tailored properties, making it particularly attractive for biomedical applications such as bone implants, scaffolds, and load-bearing devices. By enabling lightmass designs, complex geometries, and tunable mechanical behavior, LPBF offers unique opportunities for matching implant performance with biological and mechanical requirements. However, the intricate coupling between LPBF process parameters and the resulting structural, microstructural, and mechanical properties remain a major challenge for achieving the consistency and reliability demanded in clinical practice. This review comprehensively analyzed the effects of key LPBF parameters, such as laser power, scanning speed, and layer thickness on dimensional accuracy, relative density, microstructure, and surface roughness of metallic cellular structures. Their subsequent influence on mechanical performance, such as strength, fatigue resistance, and functional behavior, was critically discussed with a focus on biomedical relevance. In addition, the role of lattice design variables, including topology, unit cell size, and build orientation, was examined, highlighting their importance in optimizing mechanical integrity and biocompatibility. Current challenges, such as surface defects, geometric deviations, and microstructural heterogeneity, were identified as critical barriers to broader biomedical adoption. Finally, future perspectives emphasize process optimization and the integration of advanced computational approaches, particularly machine learning, to accelerate the design and manufacturing of complex, patient-specific biomedical architectures.

Abstract:The dealloying strategy based on dilute solid solution precursor holds significant importance in nanoporous metal fabrication. While conventional dealloying is constrained by the narrow compositional range of binary alloys, the dilute solid solution precursors achieve precise control over porous architectures by substantially expanding the tunable compositional range and optimizing kinetic pathways. Results show that structures such as high-aspect-ratio nanoporous microwires, ultra-high porosity freestanding thin films, and nested hierarchical nanoporous metals are fabricated, demonstrating significant advantages in functional applications: electrocatalytic materials achieve enhanced hydrogen evolution performance by optimizing surface electronic structures; solar steam generation devices leverage hierarchical porosity and localized surface plasmon resonance effects to attain broadband light absorption and efficient evaporation; and electroactuator materials overcome the limits of strain amplitude and strain rate by hierarchical network design. Critically, this strategy reveals a novel mechanism for synergistically resolving the fundamental compromise between high specific surface area/mass transfer efficiency and mechanical stability through the coordinated design of precursor composition and dealloying parameters.

Abstract:Dealloyed porous copper exhibits exceptional and adaptable functional properties, offering broad application potential in thermal management, catalytic sensing, and shock absorption. Structural regulation represents a key approach for enhancing its functional properties, whereas mechanical behavior is essential to ensure structural integrity and reliability under service conditions. Based on recent advances in structural regulation and mechanical properties of dealloyed porous copper, this review summarized the dealloying mechanisms and structural features of diverse precursor systems, including intermetallic compounds, solid solutions, and immiscible alloys, and also outlined the corresponding strategies for pore structural regulation. Moreover, it reviewed the current research progress on mechanical behavior of porous copper, and highlighted its major strengthening approaches and predictive models. Finally, this review outlined the key research directions of structural design and mechanical properties for the future.

Abstract:Porous metallic materials are a class of materials characterized by their structurally and functionally integrated features, with a well-defined pore structure being their most notable attribute. This porous structure enables them to exhibit dual characteristics of both metallic and porous materials, making them widely applicable in fields such as nuclear industry, petrochemical engineering, and aerospace. Additive manufacturing technology allows for the integrated fabrication of complex porous metallic structures, offering advantages such as high material utilization rate and precise control over pore structure. This paper reviews the current development of additive manufacturing technologies for metallic porous materials, focusing on the pore formation mechanisms and performance characteristics of additively manufactured porous metallic materials. It also summarizes their application progress in industries such as healthcare and mold manufacturing, discusses the integration of artificial intelligence in metallic additive manufacturing, and provides an outlook on the future development of this technology.

Abstract:Nanoporous metals, with their unique pore structure and excellent electrochemical properties, demonstrate significant application potential in the fields of energy and energy storage. Their structural characteristics provide a large specific surface area and superior conductivity, and their composition and structure are tunable. As a result, nanoporous metals play a crucial role in the field of energy conversion applications. This paper reviews the synthesis methods and structural regulation of nanoporous metals, with a focus on their applications in electrocatalytic reactions (such as oxygen evolution reaction and hydrogen evolution reaction) and energy storage devices (such as lithium-ion batteries, potassium-ion batteries, and supercapacitors). The results indicate that nanoporous metals not only enhance catalytic efficiency but also significantly improve battery cycle stability and energy density. However, issues such as the reproducibility of synthesis methods, long-term stability, cost, and technical challenges in practical applications require further investigation. Future research will focus on optimizing the microstructure and surface properties of nanoporous metals to achieve efficient and sustainable energy solutions.

Abstract:Nanoporous metal catalysts (NPCs) demonstrate remarkable advantages in the field of catalytic hydrogenation due to their high specific surface area, tunable pore structures, and confinement effects. This review elaborates on NPCs represented by Raney nickel, focusing on the preparation principles involving the construction of three-dimensional porous structures by chemical dealloying. It provides in-depth discussions on the key factors influencing catalytic performance from four perspectives: crystal structure, residual aluminum, pore characteristics, and dopants. Furthermore, the applications of these catalysts in the hydrogenation of unsaturated bonds, transformation of nitro/cyano-compounds, and upgrading of biomass platform molecules were reviewed, highlighting the essential role of the porous structure in providing high surface area, optimizing substance transfer pathways, and modulating reaction selectivity.

Abstract:Titanium and titanium alloys, owing to their low density, high specific strength, and excellent corrosion resistance, are widely used in aerospace and marine engineering. The development of additive manufacturing has enabled new approaches for fabricating complex titanium and titanium alloy components. As a solid-state additive manufacturing technique, cold spray has attracted considerable attention for its advantages of low deposition temperature, high spraying velocity, and minimal thermal effects. The current research status of cold spray additive manufacturing of titanium and titanium alloy coating was reviewed. The characteristics of feedstock powders and their influence on deposition behavior were introduced. The microstructure and properties of cold-sprayed deposits were analyzed, and the mechanisms and effects of strengthening strategies such as in-situ reinforcement and post-processing were summarized, providing a reference for process improvement and application expansion.