Journal of Materials Science & Technology最新文献

The photo-Fenton-like reaction holds significant promise for treating low-concentration antibiotic wastewater, yet its progress is hindered by the weak adsorption and activation ability of peroxydisulfate (PDS) and limited pH application range. This work employs density functional theory and machine learning models in tandem to craft optimal photocatalysts for tetracycline (TC) degradation across all pH ranges. Our investigation reveals that carbon dots (CDs) modified SrTiO₃ hollow nanospheres exhibit robust PDS adsorption and activation capabilities, facilitating electron transfer from the photocatalyst to SO₄^•-. Additionally, the abundant functional groups on CDs confer a protective effect on SrTiO₃, shielding it from corrosion by strong acids and bases. Consequently, CDs-SrTiO₃ demonstrates excellent photocatalytic performance across the entire pH spectrum, particularly in alkaline and extremely acidic conditions. Furthermore, CDs deposition enhances the solar utilization, specific surface active site amount, and hydrophilicity of SrTiO₃. Theoretical calculations and experimental characterizations elucidate the degradation mechanism and pathways of TC, while machine learning models optimize the experimental parameters. This work provides valuable insights into the rational design and adept preparation of high-quality photocatalysts suitable for a wide pH range towards wastewater treatment.

Solid electrolytes are the most promising candidate for replacing liquid electrolytes due to their safety and chemical stability advantages. However, a single inorganic or organic solid electrolyte cannot meet the requirements of commercial all-solid-state batteries (ASSBs), which motivates the composite polymer electrolyte (CPE). Herein, a CPE of boron nitride nanofiber (BNNF) with a high specific surface area, rich pore structure, and poly (ethylene oxide) (PEO) are reported. Anions strongly adsorb on the surface of BNNF through electrostatic interactions based on oxygen vacancies, promoting the dissociation of lithium salts at the two-phase interface. The three-dimensional (3D) BNNF network provides three advantages in the CPE, including (i) improving ionic conductivity through strong interaction between polymers and fillers, (ii) improving mechanical properties through weaving a robust skeleton, and (iii) improving stability through a rapid and uniform thermal dispersion pathway. Therefore, the CPE with BNNF delivers high ionic conduction of 4.21 × 10⁻⁴ S cm⁻¹ at 60°C and excellent cycling stability (plating/stripping cycles for 2000 h with a low overpotential of ∼40 mV), which results in excellent electrochemical performance of LiFePO₄ (LFP) full cell assembled with CPE-5BNNF-1300 (152.7 mAh g⁻¹ after 200 cycles at 0.5 C, and 134.8 mAh g⁻¹ at 2.0 C). Furthermore, when matched with high-voltage LiNi_0.6Co_0.2Mn_0.2O₂ (NCM622), it also exhibits an outstanding rate capacity of 120.4 mAh g⁻¹ at 1.0 C. This work provides insight into the BNNF composite electrolyte and promotes its practical application for ASSBs.

The plastic deformation introduced during the cooling stage (above 1000°C) of directional solidification is one of the primary reasons for the recrystallization of Ni-based single-crystal (SX) turbine blades in aero-engines during subsequent heat treatment. An as-cast SX superalloy DD33 was compressed at 1200°C with a Gleeble thermo-mechanical simulator to mimic such deformation. The microstructural evolution, dynamic recovery, and dynamic recrystallization nucleation of the as-cast SX superalloy during hot deformation are investigated. The results show that the highest stored energy occurs in the vicinity of the eutectics, and its energy in the interdendritic regions is higher than that in the dendrite cores/arms. The formation of deformation bands and related transition bands near the eutectics are the primary characteristics of microstructural evolution during hot deformation. The dynamic recovery in the eutectic regions includes the entanglement and annihilation of dislocations at eutectic/matrix interface, within nearby γ matrix or within the eutectic γ′ phase, as well as the formation of dense dislocation networks in these sites. Subsequently, the low-angle grain boundaries in the transition bands migrate, merge, and finally transform into high-angle grain boundaries. In other words, the recrystallized grains nucleate near the eutectics via subgrain growth. In contrast, the dislocations only tangle and annihilate at the γ/γ′ interfaces in other interdendritic regions and the dendrite cores/arms without initiating recrystallization under moderate plastic deformation (ε_p = 11.9%). This study will be helpful for understanding the local microstructural evolution of SX superalloys during directional solidification, as well as the recovery and recrystallization nucleation during the subsequent annealing.

Tribocorrosion readily removes the protective corrosion product, creates new reactive corrosion sites and thus accelerates material loss in metallic materials. This is evidenced by a pronounced or gradual decline in open circuit potential (OCP) during tribocorrosion assessments. Here we report that grain refinement can not only enhance wear resistance in dry conditions, but also induce an anomalously stable OCP variation and fortify tribocorrosion resistance in ultrahigh-purity magnesium during tribocorrosion. The tribocorrosion tests revealed that the fine-grained Mg (FG-Mg) sample exhibited a wear rate (4.56 × 10⁻⁴ mm³/Nm) approximately half that of the coarse-grained Mg (CG-Mg) sample (7.87 × 10⁻⁴ mm³/Nm). CG-Mg showed a gradual OCP decrease, associated with a thin, unprotective tribocorrosion layer, even thinner than that resulting from dry sliding. Conversely, FG-Mg exhibited stable OCP evolution and quasi-linear tribocorrosion kinetics over time, attributed to a thick, protective tribocorrosion layer. Transmission electron microscopy data suggest that high-diffusivity pathways for oxygen along grain boundaries at the early tribocorrosion stages facilitate the formation of a continuous, protective MgO layer and an adjacent oxidized layer with a depth-dependent oxygen content gradient, enhancing tribocorrosion resistance in FG-Mg. Our findings offer valuable insights for strategically tailoring tribocorrosion resistance by modulating the OCP variation of highly active metals and alloys.

Baroclaoric materials have attracted extensive attention for their promising applications in low-carbon refrigeration technology. Given that the performances of barocaloric materials are intrinsically and even inversely correlated, an overall trade-off is necessitated. Here, we have prepared the 1-bromoadamantane-graphene composite (15 wt.% graphene), whose pressure-induced entropy change, pressure-induced adiabatic temperature change, and thermal hysteresis nearly remain unchanged. The pressure-induced adiabatic temperature change is comparable to the prototype neopentylglycol while the thermal hysteresis is much smaller. More importantly, by incorporating the additive the thermal conductivity has been elevated by 10 times. Such a combination renders the composite state-of-the-art barocaloric performances and is expected to benefit the design of barocaloric refrigeration technology.

Grain boundary strengthening and precipitation strengthening can increase the strength of a material by several times, but this benefit usually leads to a sharp loss of ductility. In this work, a thermomechanical processing method combining cryo-rolled and single-step annealing was proposed to obtain a strength–ductility balance Al₅Ti_2.5Fe₂₅Cr₂₅Ni_42.5 high-entropy alloy (HEA). The cryo-rolled HEA is comprised of HCP- and BCC-martensite induced by deformation, along with a residual FCC matrix. After single-step annealing in 900°C, a structure with L1₂ and BCC double precipitates was formed through partial recrystallization and phase transformation to obtain excellent mechanical properties. The Phase-field crystal (PFC) method was used to confirm that the plasticity of high-angle grain boundary (HAGB) system is better than that of low-angle grain boundary (LAGB) with high-density dislocation system. The excellent mechanical properties of Al₅Ti_2.5Fe₂₅Cr₂₅Ni_42.5 HEA with ultimate tensile strength of 1214.4 MPa and fracture strain of 25.8% at room temperature were obtained. EBSD and TEM characterizations show that the excellent mechanical properties are mainly derived from the favorable coherent spherical L1₂ precipitation and the high number density of annealing twins.

This study investigates the adsorption mechanism, the film formation process, and the inhibition performance of benzotriazole (BTAH) on carbon steels with different grain sizes (i.e., 24.5, 4.3, and 0.6 µm) in 3.5 wt.% NaCl solution. The results demonstrate that grain refinement significantly impacts the adsorption and inhibition performance of BTAH on carbon steels. Ultra-refinement of steel grains to 0.6 µm improves the maximum inhibition efficiency of BTAH to 90.0% within 168 h of immersion, which was much higher than that of the steels with 24.5 µm (73.6%) and 4.3 µm grain sizes (81.7%). Notably, grain sizes of 4.3 and 0.6 µm facilitate a combination of physisorption and chemisorption of BTAH after 120 h of immersion, as evidenced by the X-ray photoelectron spectroscopy (XPS) results and Langmuir adsorption isotherms, while BTAH adsorbed on carbon steels with a grain size of 24.5 µm through physisorption during the 168 h of immersion. Ultra-refinement of grains has beneficial impacts on promoting the formation of a stable and dense corrosion inhibitor film, leading to improved corrosion resistance and the mitigation of non-uniform corrosion. These advantageous effects can be attributed to the higher adsorption energy at grain boundaries (approximately –3.12 eV) compared to grain interiors (ranging from –0.79 to 2.47 eV), promoting both the physisorption and chemisorption of organic corrosion inhibitors. The investigation comprehensively illustrates, for the first time, the effects of grain size on the adsorption mechanism, film formation process, and inhibition performance of organic corrosion inhibitors on carbon steels. This study demonstrates a promising approach to enhancing corrosion inhibition performance through microstructural design.

High pressure solution treatment, followed by ambient pressure aging treatment, may serve as a powerful tool for enhancing the alloy properties by tailoring plenty of nanoscale precipitates. However, no theoretical descriptions of the microstructure evolution and prediction of mechanical properties during high pressure heat treatment (HPHT) exist. In this work, a novel atomic mobility model for binary system under pressure was first developed in the framework of CALculation of PHAse Diagram (CALPHAD) approach and applied to assess the pressure-dependent atomic mobilities of (Al) phase in the Al-Si system. Then, quantitative simulation of particle dissolution and precipitation growth for HPHT Al-Si alloys was achieved through the CALPHAD tools by coupling the present pressure-dependent atomic mobilities together with previously established thermodynamic descriptions. Finally, the relationship among composition, process, microstructure, and properties was constructed by combining the CALPHAD and machine learning methods to predict the hardness values for HPHT Al-Si alloys over a wide range of compositions and processes with limited experimental data. This work contributes to realizing the quantitative simulation of microstructure evolution and accurate prediction of mechanical properties in HPHT alloys and illustrates pathways to accelerate the discovery of advanced alloys.

Designing and manufacturing compatible multi-band stealth materials remains a great challenge. In this work, a silver-metalized polyimide photochromic composite foam is successfully fabricated by self-activating electroless silver-plating on the surface of the polyimide skeleton and followed by applying a photochromic coating on the upper surface. The effective loading of silver nanoparticles facilitates the rational construction of a conductive network in foam, improving the efficient dissipation of incident electromagnetic waves. In addition, the interconnected conductive network successfully endows it with an excellent Joule heating capability, which can be employed to effectively remove ice and/or mitigate the impact of water vapor on radar stealth performance in cold and wet weather. Besides, the low emissivity silver plating combined with superior thermal insulation of foam enables the material with excellent infrared stealth performance. Moreover, the modulation of self-adaptive photochromic coating brings a prominent visual stealth performance under different sunlight backgrounds. As a result, such excellent radar and infrared stealth performance combined with the adaptive color-switching capability provides the foam with great potential for preparing compatible multi-band materials.

The application of photocatalytic technology in algae killing is limited by the non-floatability and difficulty in recycling of the photocatalysts. Loading photocatalyst on magnetic or floatable carriers is the most popular method for overcoming the above inadequacies. In this work, a CdZnS/TiO₂ membrane photocatalyst with adjustable suspended depth (include floating) and flexible assembly is designed, which is less prone to dislodgement due to in situ synthesis and has a wider range of applicability than previously reported photocatalysts. The photocatalytic removal of Microcystis aeruginosa revealed that the suspended depth and distribution format of the CdZnS/TiO₂ membrane photocatalysts have striking effects on the photocatalytic removal performance of Microcystis aeruginosa, the photocatalytic removal efficiency of CdZnS/TiO₂-2 membrane photocatalysts for Microcystis aeruginosa could reach to 98.6 % in 60 min when the photocatalysts assembled in the form of 3 × 3 arrays suspended at a depth of 2 cm from the liquid surface. A tiny amount of TiO₂ loading allows the formation of Z-Scheme heterojunction, resulting in accelerating the separation efficiency of photogenerated carriers, preserving the photogenerated electrons and holes with stronger reduction and oxidation ability and inhabiting the photo-corrosion of CdZnS.