In order to enhance the photocatalytic performance of the Cu 2 ZnSnS 4 compound, an ionic substitution strategy was employed to partially and completely substitute Zn 2+ with Cr 3+ ions using the solvothermal method. The structural analysis reveals that partial substitution significantly improves the crystallite lattice order without disturbing the kesterite crystal structure, confirming the successful incorporation of chromium into the lattice. Morphological investigations imply the formation of spherically aggregated nanorods-like, which efficiently arise the lively surface area, at the same time as EDS analysis confirms a homogeneous elemental distribution without the formation of secondary phases. Upon comparing the photocatalytic performance of all synthesized compounds using methylene blue dye as a version pollutant, the Cu 2 Zn 0.5 Cr 0.5 SnS 4 compound showed the highest degradation efficiency of about 93% within 120 min in visible light irradiation. This more desirable overall performance is attributed to the synergistic outcomes of advanced crystallinity, changed morphology, and enhanced light absorption caused by partial Cr3 substitution. These consequences exhibit that managed ionic substitution represents an effective approach for tailoring the structural and photocatalytic residences of the Cu 2 ZnSnS 4 compound-primarily based substances for environmental remediation packages.

The inherent limitations of traditional stainless steels, particularly the inhomogeneity and instability of their passive films, may increase their susceptibility to corrosion under severe conditions. To break through the performance limits of corrosion-resistant materials, this study employed high-vacuum cold crucible suspension melting technology to prepare AlCo 0.2 Cr 1.7 FeNi 2.1 Mo 0.1 high-entropy alloy (HEA), and systematically investigated its corrosion behavior and passive film evolution in boiling HNO 3 solution compared with 321 stainless steel, thereby helping to elucidate the corrosion resistance mechanism of this HEA. Experimental results indicate that the AlCo 0.2 Cr 1.7 FeNi 2.1 Mo 0.1 HEA consists of BCC, B2, and σ phases. In boiling HNO 3 solution, its corrosion rate is significantly lower than that of 321 stainless steel, and this performance gap further widens over time. XPS results confirm that the AlCo 0.2 Cr 1.7 FeNi 2.1 Mo 0.1 HEA promotes surface oxidation through autocatalytic reduction in boiling HNO 3 , forming a hybrid passive film with Cr 2 O 3 as the matrix and Al 2 O 3 dispersed within it. This hybrid passive film structure demonstrates superior resistance to boiling HNO 3 corrosion compared to a single Cr 2 O 3 film. This study provides insights that extend beyond the corrosion resistance typically achieved by conventional materials by constructing a multi-component hybrid passive film and provides a highly promising candidate material for extreme environments such as nuclear fuel reprocessing.

The effects of adding TmCl 3 on the surface morphology, phase composition, wear resistance, and corrosion resistance of micro-arc oxidation (MAO) coatings were investigated using characterization techniques including scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The results showed that the addition of an appropriate amount of TmCl 3 could increase the oxidation voltage and improve the surface morphology of the coating. The main phases composing the coating were Rutile TiO 2 , Anatase TiO 2 , and SiO 2 , in which the Tm element existed in the form of Tm 2 O 3 . When the added concentration of TmCl 3 was 0.15 g/L, the thickness, hardness, and adhesion of the coating reached their maximum values, which were (32.4 ± 5.43) μm, (405.37 ± 10.41) HV, and (17.44 ± 3.28) N, respectively; meanwhile, the roughness and friction coefficient reached their minimum values, which were (1.678 ± 0.486) μm and (0.7454 ± 0.2808), respectively. Corrosion current density and corrosion rate both reached their minimum values, at 4.2937 × 10 −8 A·cm −2 and 1.9651 × 10 −2 mpy , and the corrosion resistance of the micro-arc oxidation coating reached its optimal level. High-temperature oxidation tests and thermal shock tests demonstrated that the addition of TmCl 3 could effectively enhance the high-temperature oxidation resistance and thermal shock resistance of TC4 titanium alloy.

Residual stress critically affects the performance and reliability of laser powder bed fusion (L-PBF) 316L stainless steel. While heat treatment (HT) is essential, existing constitutive models often fail to capture relaxation under variable temperature conditions and are limited to narrow ranges. This work quantifies the effects of HT temperature (650–900 °C), holding time and heating rate using X-ray diffraction and numerical simulations. Stress reduction is governed mainly by temperature; at 900 °C for 1 h, stresses fall below 50 MPa (>90% relief), while the influence of holding time diminishes at higher temperatures. A validated 650–900 °C model captures coupled temperature–time–rate effects and shows most stress is relieved during heating rather than soaking, enabling HT schedule optimization.

The Ti-6Al-4V alloy is widely used in the aerospace industry due to its excellent mechanical properties and corrosion resistance. However, its limited wear resistance limits its service life. To address this issue, depositing a CuNiIn coating on the surface of the Ti-6Al-4V alloy has been proposed as an effective strategy. In this study, the CuNiIn coating was prepared by supersonic plasma spraying. The influence of the flight and deposition morphology of different particle sizes on the microstructure of the coating was systematically investigated. At the same time, the effect of friction parameters on the wear mechanism of the coating was studied. The microstructure of the coating was analyzed using scanning electron microscopy and X-ray diffraction. The Vickers hardness tester measured the micro-hardness of the coating. Additionally, the evolution of wear morphology and damage mechanism under different loads was investigated. The results show that as the particle size of the CuNiIn powder increases, the flight speed and temperature of the particles gradually decrease. Due to the increasingly prominent unmelted particle morphology on the coating surface, the surface roughness of the coating increases from 4.3 μm to 18.6 μm. Medium-sized particle powders have better deposition morphology, with the lowest porosity of the coating being 2.62%. Coatings with higher density have the optimal hardness and elastic modulus of 163.1 HV and 122.8 GPa, respectively. When the load increases to 20 N, the dominant wear mechanism shifts from abrasive and oxidative wear to a combined wear mechanism of abrasive, adhesive, and oxidative wear. This study provides a theoretical basis for the application of enhanced CuNiIn coatings.

Ab initio molecular dynamics (AIMD) simulations and density functional theory (DFT) are utilized to resolve the interfacial reactions in Alloy 690 under high temperature and high pressure Pb(OH) 2 solution. Pb ions preferentially bind to Ni atoms whereas Cr and Fe atoms exhibited preferential adsorption for OH − ions. Moreover, tetrahedral and octahedral interstitial H are taken into considerations for investigating the influence of interstitial H to the initial interaction. The tetrahedral interstitial H presented diffusion from Alloy 690 matrix. While H atoms occupying octahedral interstitial positions enhanced surface adsorption processes. These findings offer a predictive framework for understanding PbSCC and the impact of interstitial H on the interfacial reactions in Alloy 690 under high temperature and high pressure Pb(OH) 2 solution.

High-entropy alloys (HEAs), exemplified by the AlCoCrFeNi system, have garnered significant interest in materials science owing to their superior mechanical properties, including exceptional strength and hardness, characteristics that render them particularly well suited for wear-resistant applications. Recent developments have demonstrated that the incorporation of ceramic reinforcement phases into AlCoCrFeNi-based matrices represents an effective strategy for enhancing tribological performance via composite coating architectures. This review offers a comprehensive examination of coating systems, including reinforcement phase selection criteria and matrix functionality. A systematic analysis of matrix-strengthening approaches is provided, elucidating fundamental mechanisms and detailing how variations in alloying elements drive microstructural evolution and consequent improvements in wear resistance. Particular attention is devoted to interfacial optimization, offering a detailed discussion of interface characteristics and optimization strategies achieved through adjustments in elemental composition. Finally, the present limitations of AlCoCrFeNi composite coatings are reviewed, and prospective research avenues are suggested.

With the rapid advancement of the information age, electromagnetic waves have brought convenience to people while also posing numerous problems and challenges. Developing absorptive materials that combine strong absorption, wide bandwidth, low density, and high stability has become a core research direction in the field of materials science. Using the hydrothermal method, a flower-like zinc oxide/multi-walled carbon nanotube nanocomposite was synthesized with hydroxylated multi-walled carbon nanotubes as the carrier. This was achieved by selecting different solvents and varying concentrations of zinc precursor solutions. The composite was then blended with 50 wt% paraffin wax to investigate its electromagnetic parameters and absorptive properties. Results indicate optimal absorption performance occurs in a mixed solvent of deionized water: anhydrous ethanol = 1:1, with a zinc oxide precursor concentration of 0.2 mol/L. At a sample thickness of 2.5 mm, the minimum reflection loss reaches −40.15 dB, and the effective absorption bandwidth spans 2.88 GHz (8.00–10.88 GHz). The synergistic design strategy of “hydroxylated carrier-flower-like structure-mixed solvent” provides an innovative and practical new pathway for preparing high-performance zinc oxide/multi-walled carbon nanotube absorber materials.

In this study, aluminum alloy 7075-T651 plates were welded using conventional variable polarity gas tungsten arc welding (VP-GTAW) and variable polarity GTAW with a pulse-current wave-coupled mode (CPVP-GTAW). In CPVP-GTAW, pulse frequencies of 1–2 Hz and duty ratios of 33–67% were applied while maintaining comparable heat input to that of VP-GTAW. A combination of optical microscopy, EPMA, EBSD, fish-bone crack testing, and localized electrochemical impedance spectroscopy was employed to systematically characterize microstructural evolution, solidification cracking susceptibility, and micro-electrochemical behavior. The coupled pulse waveform generated a periodically reheated mushy zone at the trailing edge of the weld pool, where the temperature was estimated to reach 476–632 °C within the semi-solid range. As a result, the solidification cracking susceptibility index decreased from 91 in VP-GTAW welds to 27 in optimized CPVP-GTAW welds. In addition, localized electrochemical impedance spectroscopy revealed a significantly reduced micro-scale impedance inhomogeneity in CPVP-GTAW welds, indicating improved local electrochemical stability. These results demonstrate that CPVP-GTAW effectively suppresses micro-segregation, mitigates solidification cracking, and homogenizes micro-electrochemical properties in 7075 aluminum alloy welds.

A novel Al–5Ti–0.25C–4Sr master alloy was synthesized sustainably from Al/Ti machining chips to overcome Si poisoning in A356 alloys. The master alloy exhibited synergistic α-Al grain refinement and eutectic Si modification in A356 alloy. The optimal addition (1.2 wt%) effectively reduced the average α-Al grain size and eutectic Si were reduced by 46.5% and 69.3%, leading to a 53.1% enhancement in ultimate tensile strength (150 MPa) compared to the unmodified alloy. Microstructural analysis revealed that the refinement stems from heterogeneous nucleation on TiAl 3 , TiC, and Ti 2 Al 20 Sr particles. The modification was attributed to Sr-induced twinning, which was further elucidated by first-principles calculations showing strong Sr adsorption on the Si (100) surface. This work provides a cost-effective and eco-friendly strategy for high-performance Al-Si alloy production.