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Realizing improved strength–ductility synergy in eutectic alloys acting as in situ composite materials remains a challenge in conventional eutectic systems, which is why eutectic high-entropy alloys (EHEAs), a newly-emerging multi-principal-element eutectic category, may offer wider in situ composite possibilities. Here, we use an AlCoCrFeNi 2.1 EHEA to engineer an ultrafine-grained duplex microstructure that deliberately inherits its composite lamellar nature by tailored thermo-mechanical processing to achieve property combinations which are not accessible to previously-reported reinforcement methodologies. The as-prepared samples exhibit hierarchically-structural heterogeneity due to phase decomposition, and the improved mechanical response during deformation is attributed to both a two-hierarchical constraint effect and a self-generated microcrack-arresting mechanism. This work provides a pathway for strengthening eutectic alloys and widens the design toolbox for high-performance materials based upon EHEAs. Producing in situ composite materials with superior strength and ductility has long been a challenge. Here, the authors use lamellar microstructure inherited from casting, rolling, and annealing to produce an ultrafine duplex eutectic high entropy alloy with outstanding properties.

Non-centrosymmetric NdAlGe is considered to be a candidate for magnetic Weyl semimetal in which the Weyl nodes can be moved by magnetization. Clarification of the magnetic structures and couplings in this system is thus crucial to understand its magnetic topological properties. In this work, we conduct a systematical study of magnetic properties and critical behaviors of single-crystal NdAlGe. Angle-dependent magnetization exhibits strong magnetic anisotropy along the c -axis and absolute isotropy in the ab -plane. The study of critical behavior with H ∥ c gives critical exponents β = 0.236(2), γ = 0.920(1), and δ = 4.966(1) at critical temperature T C = 5.2(2) K. Under the framework of the universality principle, M ( T , H ) curves are scaled into universality curves using these critical exponents, demonstrating reliability and self-consistency of the obtained exponents. The critical exponents of NdAlGe are close to the theoretical prediction of a tricritical mean-field model, indicating a field-induced tricritical behavior. Based on the scaling analysis, a H – T phase diagram for NdAlGe with H ∥ c is constructed, revealing a ground state with an up-up-down spin configuration. The phase diagram unveils multiple phases including up-up-down domains, up-up-down ordering state, polarized ferromagnetic (PFM), and paramagnetic (PM) phases, with a tricritical point (TCP) located at the intersection [ T TCP = 5.27(1) K, H TCP = 30.1(3) kOe] of up-up-down, PFM, and PM phases. The multiple phases and magnetic structures imply a delicate competition and balance between variable interactions and couplings, laying a solid foundation for unveiling topological properties and critical phenomena in this system.

Semitransparent organic solar cells (ST‐OSCs) offer potentially more opportunities in areas of self‐powered greenhouses and building‐integrated photovoltaic systems. In this work, the effort to use a combination of solution‐processable gold nanobipyramids (AuNBPs)‐based hole transporting layer and a low/high dielectric constant double layer optical coupling layer (OCL) for improving the performance of ST‐OSCs over the two competing indexes of power conversion efficiency (PCE) and average visible transmittance (AVT) is reported. The fabrication and characterization of the ST‐OSCs are guided, at design and analyses level, using the theoretical simulation and experimental optimization. The use of a low/high dielectric constant double layer OCL helps enhancing the visible light transparency while reflecting the near‐infrared (NIR) photons back into the photoactive layer for light harvesting. NIR absorption enhancement in the ST‐OSCs is realized through the AuNBPs‐induced localized surface plasmon resonance (LSPR). The weight ratio of the polymer donor to nonfullerene acceptor in the bulk heterojunction is adjusted to realize the maximum NIR absorption enhancement, enabled by the AuNBPs‐induced LSPR, achieving the high‐performance ST‐OSCs with a high PCE of 13.15% and a high AVT of 25.9%. Semitransparent organic solar cells offer potentially more opportunities in areas of self‐powered greenhouses and building‐integrated photovoltaic systems. The use of a combination of solution‐processable gold nanobipyramids‐based hole transporting layer and a low/high dielectric constant double layer optical coupling layer for improving the cell performance over the two competing indexes of power conversion efficiency and average visible transmittance is reported.

The improvement of the creep properties of single-crystal superalloys is always strongly motivated by the vast growing demand from the aviation, aerospace, and gas engine. In this study, a static magnetic-field-assisted solidification process significantly improves the creep life of single-crystal superalloys. The mechanism originates from an increase in the composition homogeneity on the multiscales, which further decreases the lattice misfit of γ/γ′ phases and affects the phase precipitation. The phase-precipitation change is reflected as the decrease in the γ′ size and the contents of carbides and γ/γ′ eutectic, which can be further verified by the variation of the cracks number and raft thickness near the fracture surface. The variation of element partition decreases the dislocation quantity within the γ/γ′ phases of the samples during the crept deformation. Though the magnetic field in the study destroys the single-crystal integrity, it does not offset the benefits from the compositional homogeneity. The proposed means shows a great potential application in industry owing to its easy implement. The uncovered mechanism provides a guideline for controlling microstructures and mechanical properties of alloys with multiple components and multiple phases using a magnetic field.

Understanding how the magnetic fields affect the formation of reinforced phase during solidification is crucial to tailor the structure and therefor the performance of metal matrix in situ composites. In this study, a hypereutectic Al-40 wt.%Cu alloy has been directionally solidified under various axial magnetic fields and the morphology of Al 2 Cu phase was quantified in 3D by means of high resolution synchrotron X-ray tomography. With rising magnetic fields, both increase of Al 2 Cu phase’s total volume and decrease of each column’s transverse section area were found. These results respectively indicate the growth enhancement and refinement of the primary Al 2 Cu phase in the magnetic field assisting directional solidification. The thermoelectric magnetic forces (TEMF) causing torque and dislocation multiplication in the faceted primary phases were thought dedicate to respectively the refinement and growth enhancement. To verify this, a real structure based 3D simulation of TEMF in Al 2 Cu column was carried out and the dislocations in the Al 2 Cu phase obtained without and with a 10T high magnetic field were analysed by the transmission electron microscope.

The effect of axial static magnetic field (ASMF) on inclusion removal during the magnetically controlled electroslag remelting M2 high-speed-steel was investigated. The results showed that the application of ASMF can significantly increase the inclusion removal efficiency, especially for the inclusions larger than 20 μm. The reason for the accelerated removal of inclusions was attributed to the alternating Lorentz force and the magnetically controlled spin-vibration induced in the liquid melt film after the application of ASMF.

Processing metallic alloys under a static magnetic field (SMF) has garnered significant attention over the past few decades. SMFs can influence both the thermodynamics and kinetics of the solidification process by introducing extra force and energy. Eutectic-type alloys (ETAs) are commonly used as research materials under SMFs due to their featured microstructures. This review aims to present theoretical and experimental results regarding ETAs under SMFs, from post-analysis to in situ observation, to demonstrate the effects of magnetic phenomena such as magnetic braking, thermoelectric magnetic convection, magnetic gradient force, and magnetic energy on the thermodynamics and kinetics of microstructural evolution. In this paper, we adopt a hybrid approach between a review and an overview to comprehensively examine the effect of SMFs on the solidification process. Firstly, we provided a concise review of the historical research on the SMF’s impact on solidification in the literature. Next, we elucidated the basic physical principles of an SMF in material processing, followed by an introduction of numerous laboratory and industrial experiments that have utilized SMFs. Finally, we summarized the effects of SMFs on solidification in the past and provide insights into future research directions.

Solidification of Al-Cu alloys has been investigated using a 29 Tesla super high static magnetic field (SHSMF). The results show that, by imposing a 29 Tesla SHSMF, the size of primary phases and spacing of eutectic structure have been refined through the increase of undercooling which results from the suppression of diffusion coefficient. The diffusion coefficient of atoms in the liquid matrix decreases to be about 1.2 × 10 −12  m 2 /s. The lattice constants are reduced and high dislocation density forms in the primary phase, which induces a solute trapping effects. The spacing of (110) plane in Al 2 Cu is corrected to be 4.3123 Å and 4.2628 Å for Al-40  wt .%Cu alloys treated without and with a SHSMF. The spacing of (111) plane in Al is corrected to be 2.3351 Å and 2.3258 Å for Al-26  wt .%Cu alloys treated without and with a SHSMF. The compression yield strength has been improved by about 42% from 268 MPa to 462 MPa for Al-26  wt .%Cu and 42.5% from 248 MPa to 431 MPa for Al-40  wt .%Cu. The maximum elastic strain increases from about 2% to 4.3% for Al-26  wt .%Cu and from 2% to 4% for Al-40  wt .%Cu. It is expected that SHSMF is beneficial to process materials with high mechanical properties.

The grain refinement of 2024 Al alloy inoculated with Al-5Ti-1B master alloy in a steady magnetic field (SMF) was investigated. It was shown that the degradation in grain refinement was enhanced and a cellular–dendritic transition of equiaxed primary α-Al grains occurred under the SMF. Employing a differential scanning calorimeter, the nucleation temperature of primary α-Al phase was found to decrease in the SMF, i.e., the undercooling was enhanced, and the kinetics of phase transformation was modified in the SMF. The enhanced degradation in grain refinement and increase in undercooling are attributed to the modified solid/liquid interfacial free energy and the delay of formation of critical nucleus due to the retarded migration rate of atoms in the liquid phase in the SMF. The cellular–dendritic transition of primary α-Al grains is ascribed to the modified constitutional undercooling at the solid/liquid interface, which results from the change in solute distribution by the damped convection and retarded diffusivity in the SMF. Additionally, the increase in growth dimension and the modified solid/liquid interfacial free energy under the SMF are also responsible for the enhanced constitutional undercooling and the cellular–dendritic transition.

Fe–6.5 Si–0.05 B alloy was used in the study to investigate the texture evolution and magnetic property of the ferromagnetic crystal under an axial high magnetic field during bulk solidification. Optical microscopy (OM) and X-ray diffraction (XRD) were applied to analyze the microstructures and texture evolution of the alloy solidified under different magnetic field intensities. The result shows that with an increase in the magnetic field intensity from 0 to 2 T, the texture gradually changes from random orientation to {100} 〈120〉, eventually becoming a mixture of cube and Goss texture. The alloys treated at 1 and 2 T showed magnetic anisotropic behavior, while the alloy treated at 0 T showed magnetic isotropic behavior. The change in magnetic property comes from the evolution of α-Fe crystal orientation. Furthermore, a method for controlling the crystallization process and crystallographic orientation by adjusting the magnetic field intensity was proposed.