Search Results (491)

The use of Mg-based alloys as anode materials in nickel–metal hydride (Ni–MH) batteries is significantly limited by rapid capacity loss during charge–discharge cycles. This study conducts a comprehensive examination of how variations in the concentrations of Mg and Pd impact the microstructural characteristics and electrochemical behavior of Mg–Pd–Ni ternary alloys, aiming to enhance cyclic durability and uncover the fundamental degradation mechanisms. This work demonstrates that increasing the Mg content tends to reduce the reversibility of electrochemical hydrogenation/dehydrogenation reactions and exacerbates the corrosion behavior of the milled Mg–Pd–Ni alloy electrodes, thus accelerating their capacity decay. On the contrary, raising the Pd content contributes to improving the reversibility of electrochemical hydrogenation/dehydrogenation reactions and the kinetic behavior of the alloys, yet it does not enhance corrosion resistance. Full article

Sn-3Ag-0.5Cu-xBi alloys (SAC305-xBi) represent promising lead-free alternatives for low-temperature soldering. Low Bi concentrations can strengthen SAC-based solders through solid-solution strengthening, refining β–Sn grains and transforming needle-like Ag₃Sn phases into equiaxed morphologies. However, excessive Bi alloying may induce precipitation of brittle Bi particles, cause microstructural instability and interfacial degradation, thereby weakening the solder joint performance. As such, the concentration of Bi in the SAC305 alloys should be carefully controlled. In this work, the microstructure and corrosion behavior of Sn-3Ag-0.5Cu-xBi solder alloys (SAC305-xBi, where x = 0, 1, 2 and 4 wt. %) were investigated. Attention has been paid to the influence of low Bi concentration on the microstructure, morphology, and chemical composition of the phases present in the solder alloys before and after corrosion exposure. The alloys were prepared by induction melting of Sn, Ag, Cu and Bi lumps under Ar gas. The microstructure of the SAC305 and SAC305-1Bi alloys represented a hypoeutectic microstructure with dendritic (Sn) grains and the ternary eutectic, consisting of (Sn), Cu₆Sn₅ and Ag₃Sn, located in inter-dendritic regions. In the SAC305-2Bi and SAC305-4Bi alloys, a segregation of (Bi) particles was observed in addition to dendritic (Sn) and ternary eutectic. The (Bi) particles were located at the (Sn)Ag₃Sn interface in the inter-dendritic spaces of the (Sn) solid solution. The corrosion resistance of the as-cast alloys was studied in aqueous NaCl electrolyte (3.5 wt. %) using electrochemical methods. Open circuit potentials of the alloys were found to increase with increasing concentration of Bi. The highest corrosion current was found for the SAC305-1Bi alloy. It was observed that micro-galvanic cells at the Sn-Ag₃Sn interface were the initiating factors of corrosion in the SAC305-1Bi alloy. The corrosion activity of the SAC305-1Bi alloy is related to the high density of fine Ag₃Sn particles. The higher fraction of Ag₃Sn particles provided a dense network of local galvanic interaction sites, leading to the acceleration of the corrosion rate. The presence of discrete Bi precipitates in the SAC305-2Bi and SAC305-4Bi alloys, on the other hand, partially reduced the risk of galvanic corrosion. Since Bi has a higher standard electrode potential compared to Sn, the Bi/Ag₃Sn and Bi/Cu₆Sn₅ couples were less prone to corrosion. The corrosion mechanism of the SAC305-xBi alloys is discussed, and results are compared to previously studied SAC-Bi alloys. Full article

Aiming at the rapid corrosion of degradable magnesium alloys in physiological environments and the insufficient long-term protection of single plasma electrolytic oxidation (PEO) coatings, Mg-Mn-Fe layered double hydroxide (LDH) and baicalin (BA)-loaded LDH/BA composite coatings were prepared in situ on PEO-pretreated ZE21C magnesium alloy substrates. BA was stably anchored on the LDH surface via coordination bonds between its oxygen-containing functional groups and laminate metal sites. Benefiting from the physical barrier of the LDH lamellar structure and the corrosion inhibition effect of baicalin, the LDH/BA coating significantly improved the corrosion resistance of the magnesium alloy matrix. The composite coating exhibited peroxidase-like catalytic activity for reactive oxygen species generation, which could be enhanced by near-infrared irradiation. It also possessed stable photothermal conversion performance and pH-responsive drug release behavior under acidic conditions. Biological characterization demonstrated that BA-loaded LDH composite coatings exert potent inhibitory effects on 143B cell proliferation. This work integrates long-term corrosion resistance, controlled drug release, and photoresponsive catalytic functions onto magnesium alloy surfaces, providing an effective strategy for developing high-performance biodegradable magnesium alloys. Full article

The interfacial reaction between solder and substrate is a critical factor governing joint reliability, making it essential to understand the formation and stability of interfacial reaction layers when developing new high-temperature lead-free solders. This study investigates the interfacial reaction layers formed in Zn-5Al-3Mg solder/Cu substrate joints soldered at 693 K under vacuum. With a binary Zn-Al solder, the Cu substrate is progressively consumed by Zn, and the intermediate phases CuZn₄, Cu₅Zn₈, and CuZn nucleate and grow concurrently at the solder interface. The addition of a minor amount of Mg to the Zn-Al alloy, however, fundamentally alters this reaction sequence. Transmission electron microscopy analyses, including scanning transmission electron microscopy–energy-dispersive X-ray spectroscopy (STEM-EDS), energy-filtered TEM (EF-TEM), and electron diffraction, reveal three distinct interfacial layers: an outer Mg₂Zn₁₁ layer, a middle two-phase mixture of CuZn₄/Mg₂CuZn₃, and an inner Cu₅Zn₈ layer adjacent to the Cu substrate. The biphasic CuZn₄/Mg₂CuZn₃ mixture layer is shown to form via a quasi-peritectic reaction governed by sequential four-phase equilibria in the Zn-Mg-Cu ternary system. These findings demonstrate that minor Mg additions redirect the interfacial reaction pathway between Zn-Al-based solders and Cu substrates, providing new insight for the design of high-temperature Pb-free solder systems. Full article

Additive manufacturing (AM) is increasingly being considered to produce large aluminum components for aeronautical applications. Larger parts lead to longer build durations, numerous lasers and may result in prolonged exposure to high temperatures if heat dissipation is insufficient, causing in situ ageing during manufacturing and a consequent reduction in the mechanical properties of as-built aluminum alloys. This study investigates the relationship between process parameters, heat dissipation, and resulting mechanical properties in large-scale A357-AlSi7Mg0.6 aluminum alloy manufactured by laser powder bed fusion (LPBF). In the context of developing geometrically complex casings or components using LPBF equipment with multiple lasers (up to 12), mechanical testing of first prototypes revealed up to a 30% reduction in mechanical properties in certain regions, attributed to insufficient heat dissipation during the build. Thermal modelling and in situ experimental measurements have shown that the high thermal mass and extended build times of large components lead to non-uniform temperature distributions, promoting undesired microstructural evolution and advanced over-ageing, effects that are generally less pronounced in smaller specimens reported in the literature. Hardness mapping on samples subjected to monitored ageing ranges, as well as on additively manufactured rods with deliberate geometries for heat accumulation, confirmed that areas with insufficiently optimized support show significant decreases in hardness due to inefficient heat dissipation. A numerical model was developed to link the hardness evolutions to both ageing time and temperature, enabling improved predictions of microstructure and properties as a function of build and heat-removal strategies. These findings emphasize the critical importance of support structure optimization for both mechanical support and thermal management during LPBF, as well as the need for tailored process and post-process heat treatments to achieve consistent and reliable mechanical properties in large, additively manufactured aluminum alloy components. Full article

Commercial aluminum (Al) metals contain unavoidable impurities, such as iron (Fe) and silicon (Si). Due to its low solubility and high chemical affinity to Al, Fe exists in the form of Fe-containing intermetallic compounds (Fe-IMCs), which are crucial in solidification processes, determining the micro-structure and consequently the mechanical performance of the cast parts. Meanwhile, Si, as an impurity or addition, may join the binary Fe-IMCs. Here, we investigate the Si stabilization effects on the frequently observed Al-rich Fe-IMCs in a comprehensive and systematic way using a first-principles density-functional theory (DFT) approach. The study reveals different Si stabilization effects on the cubic α- and hexagonal α’-phase, as well as other binaries: Al₁₂Fe, η-Al₆Fe, τ₄-, β-, and θ-phases. The enhancement of stability for the α-phase is moderate, while it is strong for the α’-phase. For the stability series (from higher to lower) is θ-Al₁₃Fe₄ > η-Al₆Fe > α-Al₄.₇₅Fe in the binary system, while it becomes τ₄-(Al,Si)₅Fe > β-Al₄.₅SiFe > α’-(Al,Si)₄.₁₇₄Fe for the ternary Fe-IMCs. The information obtained here helps understand the formation of Fe-IMCs particles during casting of Al-Si alloys, and the design of novel Al alloys of fine micro-structures and desired mechanical performances of the products from the primary Al and the scraps and wastes. Full article

Cobalt–nickel–copper alloys were electrodeposited over a range of current density and with three different aqueous electrolytes having variable metal ion ratios, in order to examine changes in the deposit composition and to use them as cathodes for nitrate electrolysis. The alloys were electrodeposited galvanostatically from a citrate electrolyte onto rotating cylindrical steel substrates. The electrodeposition process exhibited anomalous codeposition behavior, favoring Co reduction over Ni and Cu. These electrodeposits were then used to examine their ability to reduce nitrate in simulated wastewater with 50 mg-N/L of NO₃⁻, sodium chloride, and sodium sulfate. Nitrate conversion and selectivity were characterized after electrolysis in a single-compartment cell with the alloys serving as the working electrode. Despite co-evolving hydrogen, the electrodeposited alloys were effective at generating both N₂ at high electrolysis current densities and ammonia species at lower values, with the deposit composition also affecting the conversion and products. It is the first demonstration of using Co-Ni-Cu ternary alloys for nitrate reduction. Full article

In this work, ternary Mo–Ni–X (X = Al, Co, Cr, Cu, Fe, W) thin films with nominal composition Mo₈₀Ni₁₀X₁₀ (at. %) were prepared by magnetron sputtering and evaluated as electrocatalysts for the hydrogen evolution reaction (HER) in alkaline media. The influence of alloy composition, substrate type, and deposition temperature on catalytic performance was systematically investigated. Electrochemical screening revealed a strong dependence of HER activity on both substrate conductivity and ternary alloying, with Al-, Cr-, and W-containing systems showing the best performance on glassy carbon substrates. This highlights the importance of interfacial charge-transfer efficiency in determining catalytic behavior. The Mo₈₀Ni₁₀Cr₁₀/GC system was selected for detailed analysis. Deposition temperatures ≥ 500 °C resulted in enhanced HER activity, reaching an overpotential of η₁₀ = −222 mV at j = −10 mA cm⁻². The improved performance is attributed to temperature-induced microstructural optimization and electrochemically driven surface reconstruction, leading to the formation of a Ni-enriched active interface. AFM analysis confirmed surface restructuring during operation, with roughness increasing from ~1 to ~3 nm, indicating the formation of additional electrochemically accessible active sites. XPS results suggest partial depletion of Mo during cycling, while Cr mainly contributes to structural stabilization of the evolving thin film. Overall, the results demonstrate that HER performance is governed by the coupled effects of alloy composition, substrate-dependent charge transport, and in situ surface reconstruction. This work highlights magnetron sputtering as a scalable approach for designing homogeneous noble-metal-free thin-film electrocatalysts with tunable activity. Full article

The work is a continuation of studies , focused on the development of fundamental principles of aluminum activation by low-melting metals forming eutectic alloys with fine-grained structure and limited solid solubility. The aim of this work is to investigate the mechanism and kinetics of the interaction of aluminum-based eutectic alloys with water and aqueous electrolytes. Analysis of phase diagrams of binary systems (Al–Ga, Al–In, In–Ga, Al–Sn, Sn–Ga, Al–Zn, Zn–Ga) shows that alloy composition governs surface heterogeneity and reactivity. Ternary and quaternary systems (Al–In–Ga, Al–Sn–Ga, Al–In–Sn–Ga) exhibit enhanced interaction with water due to increased heterogeneity, leading to the formation of numerous microgalvanic couples and accelerated aluminum dissolution. The process is characterized by the stationary potential of aluminum and involves coupled chemical, electrochemical, and topochemical stages described by the Avrami–Erofeev equation, with n ≈ 1.27–2.07. An increase in the In–Ga or In–Sn–Ga fraction reduces the activation energy: 9.1 kcal/mol (82% Al–9% Ga–9% Sn), 11.4 kcal/mol (92% Al–4% Ga–4% In), and 15.5 kcal/mol (91% Al–3% Ga–3% In–3% Sn). Full article

To optimize the overall performance of as-cast 8021 aluminum alloy billets for power battery foil, this study explores how Ce addition (0–0.4 wt.%) regulates microstructure, mechanical properties, and corrosion resistance via second-phase reconstruction. Microstructure characterization, mechanical property testing and electrochemical corrosion tests were performed. The results show that Ce addition first refines, then stabilizes, and finally coarsens α-Al grains. The addition of 0.2 wt.% Ce promotes the formation of tentatively identified dispersed Al–Ce–Fe ternary phases, achieving the optimal combination of ductility (elongation: 42.7%) and strength (tensile strength: 95.0 MPa), as well as superior corrosion resistance (i_corr = 2.79 × 10⁻⁷ Acm⁻²). Excessive Ce led to possible precipitation of the Al₂Ce phase and grain coarsening, deteriorating alloy properties. In conclusion, 0.2 wt.% Ce is the optimal content to balance the microstructure, mechanical and corrosion properties of 8021 aluminum alloy, providing a theoretical basis for its compositional optimization of as-cast billet for battery foil applications. Full article

TiN coatings have been widely employed in cutting tools due to their high hardness and excellent wear resistance. While most research on nitride coatings has focused on binary (e.g., TiN) and ternary (e.g., TiAlN, TiSiN) systems, the quaternary TiMoSiN system remains comparatively underexplored. In response to the growing demand for comprehensive coating performance under increasingly complex working conditions, this work incorporates Mo and Si into the TiN system to synergistically enhance mechanical, tribological, and corrosion-resistant properties. TiMoSiN coatings were deposited onto cemented carbide substrates by arc ion plating using a Ti_0.8Mo_0.1Si_0.1 alloy target. The influence of nitrogen partial pressure (0.2–1.7 Pa) on the microstructure, mechanical properties, tribological behavior, and electrochemical corrosion performance was investigated. The results show that nitrogen partial pressure plays a critical role in regulating the chemical composition, phase structure, and preferred orientation of the coatings. As the nitrogen partial pressure increases, surface macroparticles are reduced, while the Ti and Mo contents decrease and the Si and N contents increase. The phase structure evolves from a dual-phase mixture of TiN and Ti₂N to a single TiN phase, accompanied by a shift in preferred orientation from (111) to (200). The hardness of the coatings ranges from 36.2 to 43.1 GPa, reaching a maximum of 43.1 GPa at 1.0 Pa. The coating deposited at 0.6 Pa exhibits the best overall performance: it achieves the lowest friction coefficient (0.349) and wear rate (1.08 × 10⁻⁷ mm³/(N·m)), together with the highest corrosion resistance, as reflected by the most noble corrosion potential (−152 mV) and the lowest corrosion current density (8.99 × 10⁻⁸ A·cm⁻²). This study demonstrates that nitrogen partial pressure effectively controls the microstructure and multifunctional properties of TiMoSiN coatings, providing practical process guidelines for their application in demanding cutting environments. Full article

In this paper, a ternary Tb₆₅Co₂₅Ni₁₀ amorphous tape was successfully prepared, and the glass forming ability (GFA), magnetic properties, and magnetocaloric characteristics of the amorphous tape were studied in detail. The values of the reduced glass transition temperature T_rg, parameter γ and critical section thickness Z_c indicate the good GFA of the Tb₆₅Co₂₅Ni₁₀ amorphous tape. The Tb₆₅Co₂₅Ni₁₀ amorphous tape exhibits spin-glass-like behavior, with a Curie temperature of 83 K and a spin-freezing temperature (T_f) of 73 K, and a large coercivity below T_f. The spin-glass-like behavior significantly deteriorates the magnetic entropy change (−∆S_m) of the Tb₆₅Co₂₅Ni₁₀ amorphous tape at low temperatures, resulting in the deviation of magnetic entropy change behavior from the predicted results. However, the Tb₆₅Co₂₅Ni₁₀ amorphous tape still shows an excellent magnetocaloric effect (the peak value of −∆S_m of 9.46 J kg⁻¹ K⁻¹ and the refrigeration capacity of 569.5 J kg⁻¹ under 5 T, both of which are higher than those of most other heavy rare earth-based amorphous alloys), indicating the great application potential in the field of magnetic refrigeration for the amorphous tape. Full article

Hydrogen embrittlement is a critical degradation mechanism in microalloyed and pipeline steels used in hydrogen-economy infrastructure. We present a physics-informed neural network (PINN) framework that embeds Fick’s second law and the Arrhenius temperature dependence directly into the loss function, trained on 22 temperature-dependent data points spanning pure α-Fe and API X65 pipeline steels (modern and vintage microstructures). The PINN recovered the pure-iron activation energy (4.2 kJ mol⁻¹ vs. literature 4.15 kJ mol⁻¹, R² = 1.00) and yielded Arrhenius activation energies of 28.5 and 45.2 kJ mol⁻¹ for modern and vintage X65, respectively, indicating substantially stronger trapping in older microstructures. McNabb–Foster analysis of ten ternary Fe–Me–C,N alloys revealed flat-trap binding enthalpies of 19 ± 2 kJ mol⁻¹ and deep-trap free energies of 57 ± 2 kJ mol⁻¹, with effective diffusivities spanning three orders of magnitude governed primarily by flat-trap density. The framework provides a computationally efficient and physically consistent tool for hydrogen transport prediction, with a clear roadmap for multi-feature extension incorporating compositional and microstructural descriptors. Full article

In this study, the effects of cadmium (Cd) on 4 different alloys developed by casting the Mg-Al-Mn ternary composition, in which the second element is aluminum (Al), and the third element is manganese (Mn), based on magnesium (Mg) metal, which is known as the lightest of the metallic materials in the field of engineering, were investigated. The base alloy Mg-Al-Mn (AM60) (Q1) and the Q2, Q3, and Q4 alloys were produced by adding Cd to the base alloy at rates of 0.2%, 0.5%, and 1.0%, respectively. The effects of element addition were determined by conducting Optical Microscopy (OM), X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF), Scanning Electron Microscopy (SEM), Energy-Dispersive X-Ray Spectroscopy (EDX), hardness tests, potentiodynamic polarization corrosion tests in a 3.5% NaCl environment, and wear tests under 20 N and 40 N loads. The effect of 3.5% NaCl on the alloys in corrosion and wear tests was tested. In the Mg-Al-Mn ternary alloy, the expected α-Mg, β-Mg₁₇Al₁₂, Al₈Mn₅ and AlMn phases were observed, and Cd was found to be predominantly dissolved in the matrix at the micro-level. Cd showed a fine, uniform distribution in the structure. In the hardness tests, the hardness of the alloy containing 1.0% Cd increased by approximately 16%. According to the potentiodynamic polarization corrosion test values, the corrosion potentials of the alloys were negative, but the corrosion rate (CR) increased with increasing Cd content of the alloys. In corrosive wear tests, based on the aggressive corrosive wear mechanism in a 3.5% NaCl environment, an increase in wear of approximately 25% was observed at the end of 400 m as the load increased from 20 N to 40 N. The effect of hardness on corrosive wear was found to be limited. However, it can be stated that the Cd content of the Q2 alloy, being insufficient in accelerating galvanically induced wear, may reduce friction. In the Q3 and Q4 alloys, the increasingly discontinuous β-phase morphology altered the galvanic coupling geometry, contributing to accelerated abrasive wear. In corrosive wear, only the Q2 samples performed well under both 20 N and 40 N loads in a NaCl environment. Full article

The formation of coarse brittle W₂Zr phases severely limits the dynamic mechanical performance of energetic W-Zr structural materials. In this work, Ti and Ni were introduced into the W-Zr system to modify the phase evolution during sintering, and three alloys with different Zr atomic concentrations, W_xZr_85−xTi_7.5Ni_7.5 (x = 45, 55, and 65), were prepared by vacuum sintering. Microstructural characterization showed that the W₄₅Zr₄₀Ti_7.5Ni_7.5 alloy contained abundant coarse micron-sized W₂Zr particles, whereas both the W₅₅Zr₃₀Ti_7.5Ni_7.5 and W₆₅Zr₂₀Ti_7.5Ni_7.5 alloys exhibited a lower fraction of W₂Zr together with a much finer characteristic size. In particular, decreasing the Zr content reduced the characteristic size of W₂Zr from several micrometers to below 200 nm. Interrupted sintering and thermal analyses suggest that the preferential formation of a Zr(Ti) solid solution and a Zr-Ti-Ni-rich ternary phase at lower temperatures reduces the local availability of free Zr for reaction with W, thereby suppressing the nucleation and growth of W₂Zr. Correspondingly, the dynamic compressive strength increased from 1054 MPa for W₄₅Zr₄₀Ti_7.5Ni_7.5 to 1720 MPa for W₆₅Zr₂₀Ti_7.5Ni_7.5. In addition, the W₆₅Zr₂₀Ti_7.5Ni_7.5 alloy maintained pronounced impact-induced reaction behavior despite its lower Zr content. These results indicate that tailoring the W/Zr ratio in the Ti/Ni-containing W-Zr system provides a feasible route to regulate W₂Zr formation and improve the compressive response under dynamic loading. Full article