The development of cost-effective and sustainable isotropic pitch precursors is essential for producing general-grade carbon fibers (CFs) with improved mechanical performance. Herein, a facile, catalyst-free copolymerization strategy is reported for upgrading low-cost refined ethylene tar pitch (RETP) into high-performance spinnable isotropic pitch, using refined bio-pitch (RBP) as a renewable reactive modifier. The copolymerization behavior between RETP and RBP is systematically investigated at varying mass ratios. The results reveal that RBP, rich in oxygen-containing functional groups and featuring a unique extended zigzag molecular configuration, effectively promotes radical-mediated cross-linking and polycondensation with RETP molecules under mild thermal conditions. This cooperative interaction facilitates the formation of linear macromolecular architectures with enhanced molecular weight and an appropriate aliphatic–aromatic balance, thereby significantly improving the spinnability of the resulting pitches, as confirmed by rheological measurements and fiber breakage evaluation. Optimal performance is achieved at a RETP-to-RBP weight ratio of 10:3 (RETBP-30), yielding carbon fibers (RETBP-30CF) with a tensile strength of 1427  MPa and a Young’s modulus of 52.4 GPa.

Heat resistance Al-Fe-Cr-Ti alloys achieve exceptional thermal stability, yet suffer from severe brittleness due to coarse intermetallic phases and processing defects. This study systematically investigates how processing routesspray forming (SF), hot extrusion (EX), and additive friction stir deposition (AFSD)-tailor dual-scale microstructures and mechanical properties from room temperature to 400 degrees C. SF produces extensive porosity (4.91%) and dual-scale phases (Al3Ti and Al13(Fe, Cr)4), yielding 6.5% elongation (EL). EX eliminates porosity and refines dual-scale phases, achieving 11.2% EL, but particle-decorated grain boundaries persist. AFSD converts grainboundary-segregated micron-scale Al3Ti and Al13(Fe, Cr)4 into a uniformly dispersed population by severe shear-induced fragmentation, refining their size to 1.18 and 0.8 mu m, respectively. Concurrently, nanoscale Al3Ti and Al13(Fe, Cr)4 and Al13(Fe, Cr, Ti)4 (51 nm) formed, establishing a dual-scale precipitate structure. This yields synergy-185.7 MPa yield strength (YS) with 32.1% elongation (EL) at the room temperature, representing a 187% ductility enhancement relative to the EX while maintaining comparable strength. Compared to the EX, AFSD demonstrates superior high-temperature strength retention with YS values 26.4% and 25.0% higher at 350 degrees C and 400 degrees C, respectively. In addition to the dual-scale precipitate structure, the mechanical properties derive from: (i) eliminating grain boundary embrittlement, transforming fracture from intergranular quasicleavage to intergranular ductile mode; (ii) enhanced work hardening via uniform dislocation distribution; (iii) texture weakening enabling multi-slip activation; and (iv) threshold stress strengthening through fine interparticle spacing. The study establishes that in the Al-Fe-Cr-Ti alloy, spatial distribution of strengthening phases-rather than absolute magnitude-is critical for strength-ductility synergy.

This study presents a structural-induced orientation strategy to fabricate cost-effective two-dimensional carbon/carbon composites with superior unidirectional thermal conductivity. By employing low-cost polyacrylonitrile-based carbon fibers and optimizing reinforcement architecture, the carbon matrix is guided to form highly oriented lamellar structures along the fiber axis, creating efficient thermal conduction pathways. Systematic investigation demonstrates that unidirectional fabric reinforcement significantly outperforms plain weave fabric in inducing matrix orientation, with thermal conductivity strongly dependent on the fiber volume ratio between orthogonal directions. The optimized material achieves an exceptional X-direction thermal conductivity of 400 W m-1 K-1 at a fiber volume ratio of 5:1. Cross-scale finite element modeling reveals that the oriented carbon matrix possesses an extraordinary intrinsic thermal conductivity of 1945 W m-1 K-1, substantially surpassing conventional carbon matrices and demonstrating its dominant role in heat conduction. The established model provides important insights into the heat transfer mechanisms within these architectural composites. This innovative approach simultaneously reduces raw material costs by nearly two orders of magnitude compared to conventional materials using mesophase pitch-based carbon fibers, successfully overcoming the traditional cost-performance limitations. The work provides valuable theoretical insights and practical guidance for developing next-generation thermal management materials. (c) 2026 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Vacancies play a critical role in diffusion-dominated solid-state phase transformations of materials. A classical paradigm of physical metallurgy is that quenched-in excess vacancies are tuned to regulate the precipitation hardening in lightweight aluminum alloys. Here we demonstrate that a vacancy-alloying effect, whereby a high concentration of vacancies induced by in-situ TEM heating or ion irradiation, completely overturns the traditional precipitation sequence in Al-Cu alloys microalloyed with Sc. An anomalous phase transformation appears via a spinodal decomposition process with L10-Al2Cu2 phase as the product nanoprecipitate and the traditional precipitation sequence turning GP zones into 0 '' and 0 ' precipitates is reversed. The vacancy-triggered spinodal decomposition is capable of absorbing and stabilizing vacancies continually, enabling the minor Sc-added Al-Cu alloys to reach an unprecedented resistance to void swelling or ductility degradation, even irradiated to 100 dpa. We envisage that the anomalous vacancy-accommodating phase transformation may pave a way for the development of advanced radiation-resistant metallic alloys with promising applications in nuclear industry and space missions.

This study proposed a new zirconium-contained polyborosilazane (PSNB-Zr) precursor in steps with methyldichlorosilane (MDCS), methylvinyldichlorosilane (MVDCS), hexamethyldisilazane (HMDZ), pyridine borane and zirconocene dichloride (Cp2ZrCl2) as raw materials. After pyrolysis of the PSNB-Zr, the corresponding silicoboron carbonitride containing zirconium (SiZrBCN) ceramics were obtained. This precursor structure was analyzed through Fourier transform infrared spectrometer (FT-IR), X-ray photoelectron spectrometer (XPS) and 1H nuclear magnetic resonance spectrometer (1H NMR). In addition, X-ray diffractometer (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) were carried out to analyze the ceramic microstructure and phase composition. Conversion from the precursor into the ceramic phase was investigated by TG-MS. The results suggest that the precursor has a less branched structure and is highly soluble in benzene, toluene, xylene and n-hexane. The precursor derived SiZrBCN ceramics are amorphous up to 1400 degrees C. When the precursor is heated to 1600 degrees C, SiC, Si3N4 and Zr2CN are formed, and SiC, ZrB2, Si3N4, BN multiphase ceramics are obtained upon heat-treatment at 1800 degrees C with the phase transformation of Zr2CN. During the heat treatment, the ceramics change from amorphous to crystalloid with the release of small molecule like CH4, NH3, etc. The antioxidant properties of the SiZrBCN ceramics were tested at 1100-1600 degrees C in static air atmosphere. A compact oxidation layer is prepared on the surface of SiZrBCN ceramics, which was mainly composed of SiO2, ZrO2 and ZrSiO4. The formation of ZrSiO4 inhibits the evaporation of SiO2, thus improving the oxidation performance of SiZrBCN ceramics.

Vacancies play crucial roles in various phase transformation processes in metallic solids, but their diffusion behaviors in the presence of solute elements are less known. In this work, the impacts of substitutional solute atoms on vacancy diffusion in dilute alloys are quantitatively studied. Using Al-Sn alloy system as an illustrative case, the detailed vacancy diffusion behavior under the influence of Sn atoms is revealed by atomistic kinetic Monte Carlo simulations. Accordingly, a physics-based analytic model is derived to quantify the influences of substitutional solute atoms on the vacancy diffusivity in dilute alloys. In the model, the diffusion of vacancy is rigorously treated as a combination of free diffusion within host atoms and co-diffusion together with solute atoms. Based on the vibrational frequency, migration enthalpy and binding energy of solute-vacancy pair obtained from first-principles calculations, the time fraction for a vacancy trapping by solute atoms and the corresponding correlation factor of diffusion are derived. The predicted vacancy diffusivity in the show-case Al-Sn alloys at different temperatures shows a good agreement with the diffusivity data extracted from KMC simulations within the five-frequency model framework. By using the analytical model, the retarding effects of different impurity elements on vacancy diffusion in Al alloys are screened and discussed, which will help to further exploit the influences of different solute atoms on vacancies in solid-state phase transformations in the alloys.

Porous calcium hexaluminate (CA6) is attractive for thermal insulation due to low conductivity and chemical stability at high temperatures. In this study, porous CA6 ceramics were fabricated by a direct foaming method using calcium aluminate cement (CAC) as a gelling agent and sole calcia source. The results showed that the firing temperature is a significant factor in forming the CA6. In the samples fired at 1550 and 1650 degrees C, the main phase was CA6. Especially for samples fired at 1650 degrees C, the CA6 content was as high as 90 %. With the firing temperature increased, the compressive strength of the sample using tabular alumina and high-pure ultra-fine alumina was increased significantly, while the size of foamed spherical pores was decreased. In addition to the firing temperature, the type of raw alumina plays a key role in forming the CA6. The sample using high-pure ultra-fine alumina exhibited commendable comprehensive properties. The compressive strength is 5.12 MPa, and the thermal conductivity is 0.46 W center dot m-1 center dot K-1. The work exhibited a simple process for producing porous CA6 ceramic with high porosity and commendable properties, including thermal insulation and compressive strength, using CAC as a gelling agent and sole calcia source.

In order to prevent the energy density attenuation caused by MXene Ti3C2 fragmentation during the long period potassium-ions storage in aqueous systems, the hexagon holes Ti3C2 are constructed by using the coordination strategy of defect tuning and in-situ micro-oxidation. Through experiments and theoretical calculations,it is proved that Ti4+-O-K-Ti2+/3+ polyvalent titanium interfaces improve the reaction kinetics, enhance the adsorption activity for potassium-ions, and decrease the adsorption energy barrier. The antioxidant mechanism of hexagon holes Ti3C2 with polyvalent titanium for potassium-ions storage in aqueous system is revealed. This provides a new way for the practical application of ultra-stable potassium-ions storage.

A metal-organic skeleton (MOF) -derived bimetallic sulfide catalyst, FeCoS2/Fe0.95S1.05, is proposed here for electrochemical ammonia production, which offers a sustainable and energy-saving technical solution for nitrate removal and green NH3 synthesis under environmental conditions. The catalyst benefits from the excellent conductivity and effective synergistic effect of bimetallic sulfides, and it has a NH3 yield of 2.705 mg h- 1 mgcat. - 1 , a maximum Faraday efficiency of 94.79 %, an ammonium selectivity of 96.88 %, and it also maintains good catalytic stability over 12 consecutive cycles. Theoretical and experimental results demonstrate that the incorporation of Fe into the Co site changes the electron configuration of the atoms, resulting in a more pronounced Fe-to-*NO3 electron transfer, and NO3 - can be effectively activated at the surface Fe-Co sites, thereby facilitating the NO3-RR process and realizing efficient NH3 production. Therefore, this study provides a strategy for the design of electrochemical nitrate reduction electrocatalysts.

It is difficult to generate coherent twin boundaries in bulk Al alloys due to their high intrinsic stacking fault energy. Here, we report a strategy to induce high-density growth twins in aluminum alloys through the heterogeneous nucleation of twinned Al grains on twin-structured TiC nucleants and the preferred growth of twinned dendrites by laser surface remelting of bulk metals. The solidification structure at the surface shows a mixture of lamellar twinned dendrites with ultra-fine twin boundary spacing (∼2 μm), isolated twinned dendrites, and regular dendrites. EBSD analysis and finite element method (FEM) simulations have been used to understand the competitive growth between twinned and regular dendrites, and the solidification conditions for the preferred growth of twinned dendrites during laser remelting and subsequent rapid solidification are established. It is shown that the reduction in the ratio of temperature gradient G to solidification rate V promotes the formation of lamellar twinned dendrites. The primary trunk spacing of lamellar twinned dendrites is refined by the high thermal gradient and solidification rate. The present work paves a new way to generate high-density growth twins in additive-manufactured Al alloys.

The Al and Cu atom ordering within the Al-Cu sub-lattices of the T1 phase have been unambiguously determined by a combination of high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), atomic-resolution energy-dispersive X-ray spectroscopy (EDX), STEM simulations, cluster expansion (CE) methods and density functional theory (DFT) calculations. A new ordered arrangement of Al and Cu atoms within the Al-Cu sub-lattices has been proposed. These dual Al-Cu layers exhibit orthorhombic symmetry with an AlCu2 stoichiometry, which plays a crucial role in defining the crystal structure of the T1 phase. This configuration is different from disordered or ordered atomic arrangements of the Al-Cu sub-lattices reported in previous literature. Moreover, a new T1 model with the composition of Al6Cu4Li3 is proposed based on the new Al-Cu sub-lattices, which demonstrates thermodynamic feasibility.

Single-source organic precursors of TaxHf1-xC (x = 0.2, 0.25, 0.33, 0.5) were synthesized using TaCl5, HfCl4 and phenolic resin as the sources of tantalum (Ta), hafnium (Hf) and carbon (C), respectively. The synthesized organic precursors were pyrolyzed to obtain TaxHf1-xC single-phase solid solutions with ideal solid solution structure characteristics. On this basis, preparation of TaxHf1-xC modified carbon/carbon composites (C/C-TaxHf1-xC) was achieved through precursor impregnation and pyrolysis (PIP). The formation process, microstructure and oxidation resistance of TaxHf1-xC solid solutions as well as the ablation resistance of C/C-TaxHf1-xC composites were systematically investigated. The results indicate that the pyrolysis process of TaxHf1-xC precursors involves carbothermal reduction reaction (CRR) of HfO2 and Hf6Ta2O17, and solid-solution reaction (SSR) between TaC and HfC. With the increase of Hf/Ta atomic ratio, higher temperatures are required to form TaxHf1-xC single-phase solid solutions. At the temperature of 1800-2000 degrees C, TaC and HfC formed by precursor pyrolysis undergo adequate SSR to form TaxHf1-xC single-phase solid solutions, and their composition and microstructure mainly depend on the Hf/Ta atomic ratio. The ablation resistance of C/C-TaxHf1-xC composites can be effectively improved by adjusting the Hf/Ta atomic ratio. The C/C-Ta0.5Hf0.5C and C/C-Ta0.25Hf0.75C composites exhibit superior ablation resistance, with linear ablation rates (LARs) of only 0.88 and 0.19 mu m/s, respectively. The excellent ablation resistance of C/C-Ta0.5Hf0.5C is attributed to the formation and interaction of Ta2O5 and Hf6Ta2O17, while the exceptional ablation resistance of C/C-Ta0.25Hf0.75C is due to the interlocking structure of Hf6Ta2O17.

Wood-plastic composites (WPCs) face limitations in load-bearing structural components due to inherent brittleness and inferior mechanical properties. While fiber fabric prepregs offer bidirectional reinforcement, their post-curing rigidity often compromises flexibility, increasing risks of brittle fracture in construction applications. To address this challenge, we developed carbon fabric mesh prepregs (CFMP) with gradient strength and toughness distribution through resin modification, subsequently fabricating a multi-layered composite building material (BPC-CFMP) via one-step co-extrusion molding. This process achieves precise construction of mechanical gradients tailored for architectural requirements. The optimized BPC-CFMP demonstrates breakthrough performance in critical structural metrics: tensile strength (53.9 MPa), flexural strength (63.6 MPa), and impact strengths (23.7 kJ m-2) show 87.7 %, 43.7 %, and 98.4 % improvements respectively over conventional WPCs, with a 72.9 % increase in flexural deflection (14.1 mm). Under a 10 J drop hammer test, peak impact force (1.5 kN) increased by 59.7 % while impact back surface damage area (11.8 cm-2) reduced by 48.9 %, confirming superior energy absorption capabilities. These improvements stem from synergistic mechanisms: (1) robust interfacial bonding through interpenetrating network structures enabling efficient load transfer between CFMP grids and WPC matrices, and (2) extended damage propagation paths achieved via CFMP-induced crack deflection and micro-void deformation mechanisms that enhance structural toughness. The co-extrusion strategy not only streamlines production but enables precise mechanical gradient control. This advancement provides a scalable solution for advancing WPC applications in prefabricated construction and long-span roof systems.

beta-Mg2Si is a common intermetallic phase in commercial Al alloys, which can influence the precipitation of age-hardening phases and mechanical properties. In this work, (3-Mg2Si dispersoid formed in a novel multi-components Al-Mg-Zn based crossover alloy during homogenization has been explored in detail. It is found that (3-Mg2Si owns a rarely observed cube-cube orientation relationship (OR) of [001](3//[001]Al, (100)(3//(100)Al with Al matrix, while a Si-terminated {100} interface layer can be identified. More strikingly, it is revealed that (3-Mg2Si/Al-matrix interfaces acted as preferential segregation sites for Zr, Zn and Cu atoms, causing heterogeneous nucleation of Al3Zr and T-(Al,Zn,Cu)49Mg32 phases at the interfaces. Resultantly, the growth of (3-Mg2Si could be slowed down with their transition from cube-cube to Kanno OR being hindered. The underlying mechanisms have been revealed by applying first principles calculations of segregation energies of solute atoms based on the atomistic interfacial configuration.

In many industrial Al-Mg-Si alloys, natural aging (NA) has a detrimental effect on the age-hardening response during artificial aging (AA), due to the formation of unfavorable nanometer-sized solute clusters during NA. In this work, we systematically studied the atomic structures of solute clusters formed in a dilute 6060 alloy and a more concentrated 6082 alloy after 1-year NA and their influences on the age hardening behavior during the following AA. In 6060, it was found that NA promotes the formation of high-density solute clusters in the form of GP-zones composed of 1-3 beta ''-eyes, which can act as precursors of beta '' precipitates, enhancing the age-hardening kinetics during AA. In contrast, most solute clusters in 6082 after 1-year NA are 1 beta ''-eye, binocular and square GPzones, while GP-zones containing multiple beta ''-eyes are rare. As a result, NA has a strong negative effect on the age-hardening response during AA and the peak-aged strength.

Au/CeO2(111), as an important catalyst system, has demonstrated excellent catalytic performances in a variety of fields such as the catalytic oxidation and the water-gas shift reactions. In order to reveal in depth the Au/CeO2(111) catalytic mechanism, especially to understand the interaction of the active components on an atomic scale, in this work, the adsorption properties on the Au/CeO2(111) surface are investigated by calculating the adsorption energy, differential charge density, Bader charge, and the density of states by using density functional theory (DFT+U). First, five adsorption sites of Au/CeO2(111) are identified in the planar region of CeO2(111), and the most stable adsorption configuration is found to be located at the bridging position between surface oxygen atoms (the oxygen-oxygen bridging site), which suggests that Au interacts more closely with the oxygen-oxygen bridging sites. Further, the differential charge density and Bader charge reveal the charge transfer mechanism in the adsorption process. Specifically, the Au atoms are oxidized into Au+, while the Ce4+ ions in the second nearest neighbor of Au are reduced to Ce3+, and the adsorption process is accompanied by a charge transfer phenomenon. Au also exhibits a unique adsorption behavior in the CeO2(111) step-edge region, where a highly under-allocated environment is formed due to the decrease in the coordination number of atoms in the step edge, which enhances the adsorption of Au in a highly under-allocated environment. The adsorption of Au at the step edge is enhanced by the lower coordinated environment due to the reduced coordination number of the atoms at the step edge. By comparing four different types of step structures (Type I, Type II, Type II*, and Type III), it is found that the higher adsorption energy of Au at Type II* site and that at Type III site are both mainly due to the lower coordinated state of Ce atoms at these sites. Charge transfer is also particularly pronounced at the Type III sites. It is also accompanied by electron transferring from Au to Ce4+ ions, making Type III the preferred adsorption site for Au atoms. By constructing a more comprehensive Au/CeO2 model, this study breaks through the previous limitation of focusing only on planar adsorption and reveals the adsorption mechanism of Au/CeO2 at the edge of the step, which provides a new perspective for understanding in depth the catalytic mechanism of Au/CeO2(111).

Biochar was derived from rice straw pyrolyzed at 400°C, and biochar was added to the excess sludge at the ratio of 10% DS, 25% DS, and 50% DS as a supplementary skeleton for sludge Fenton pre-treatment. Rice husk biochar mixed with fungus residue as compost conditioner. In this study, we explored the effects of seven groups of composting materials on the composting effect and fertilizer quality under different pre-treatment methods of Fenton-pretreated sludge cake and conventional dewatered sludge cake, and different biochar additions. Specifically, we conducted a 22-day composting experiment using a composting reactor to investigate the effect of rice husk biochar combined with Fenton oxidation on the physicochemical properties of sludge composting. The results of this study showed that the FB50 group significantly increased the composting rate. Nutrient analysis showed that the FB50 group was rich in fertilizer nutrients, such as available phosphorus, and alkali-hydrolyzable nitrogen content increased. Heavy metals (Cu, Cd, Cr, Pb, Zn, Ni) met China's 'Agricultural Sludge Pollutant Control Standard' GB 4284-2018 Grade A standard, with obvious passivation and significantly reduced bioavailability. All these results suggested that biochar coupled with Fenton oxidation was more beneficial to sludge composting.

The surface potential on n-type Si(111)-7×7 surface was measured at 78 K using high-frequency heterodyne-Kelvin probe force microscopy (HF-he-KPFM) method with atomic resolution. By comparing VCPD images obtained from conventional KPFM and HF-he-KPFM, we found that frequency dependence of carrier emission and capture of surface states on Si(111)-7×7 surface. Furthermore, donor- and accepter-like surface states on different atom position of Si(111)-7×7 surface are distinguished. In addition, the electric field effect of high-low Kelvin probe force spectroscopy (KPFS) was analyzed, and the dissipative force was revealed in the high-frequency KPFS. These findings underscore the potential of HF-he-KPFM as a promising method for studying semiconductor properties such as surface potential, band bending and capacitance.

Lithium dendrites belong to the key challenges of solid-state battery research. They are unavoidable due to the imperfect nature of surfaces containing defects of a critical size that can be filled by lithium until fracturing the solid electrolyte. The penetration of Li metal occurs along the propagating crack until a short circuit takes place. It is hypothesized that ion implantation can be used to introduce stress states into Li6.4La3Zr1.4Ta0.6O12 which enables an effective deflection and arrest of dendrites. The compositional and microstructural changes associated with the implantation of Ag-ions are studied via atom probe tomography, electron microscopy, and nano X-ray diffraction indicating that Ag-ions can be implanted up to 1 µm deep and amorphization takes place down to 650-700 nm, in good agreement with kinetic Monte Carlo simulations. Based on diffraction results pronounced stress states up to -700 MPa are generated in the near-surface region. Such a stress zone and the associated microstructural alterations exhibit the ability to not only deflect mechanically introduced cracks but also dendrites, as demonstrated by nano-indentation and galvanostatic cycling experiments with subsequent electron microscopy observations. These results demonstrate ion implantation as a viable technique to design "dendrite-free" solid-state electrolytes for high-power and energy-dense solid-state batteries.

A detailed understanding of the geometric structure and electronic properties of gold nanoparticles on the ceria surface is crucial for comprehending their unique catalytic activity. Using the first-principles method based on density functional theory, the adsorption of Au-x (x = 1-4) clusters on the CeO2(111) surface was studied. It was discovered that the standing configurations of Au-2 and Au-3, as well as the tetrahedral structure of Au-4, are the most stable adsorption structures. The stability of these configurations is jointly determined by the number and strength of Au-Au bonds, the Au-O bonding energy, and the interaction dynamics between the clusters and the substrate. The analysis of Bader charge, difference charge density and density of states suggested that lattice relaxation and electronic localization occur in the reduced Ce3+. The reduced amount and location of Ce3+ are significantly influenced by the position and charge transfer amount of Au-x cluster. The adsorption of CO on Au-4/CeO2(111) indicated that stronger Au-C bonding energy due to the hybridization of Au-5d and C-2p, thereby enhancing the catalytic activity for CO oxidation reactions.