The phase equilibria of the Dy-Fe-B ternary system at 873 and 1073 K were investigated experimentally in this work using the equilibrated alloy method combined with scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) and X-ray powder diffraction (XRD). The experimental analysis identified five stable ternary intermetallic compounds, namely Dy2Fe14B (τ1) with the Nd2Fe14B-type structure and space group P42/mnm, DyFe4B4 (τ3) with the Nd1+εFe4B4-type structure and space group Pccn, Dy5Fe2B6 (τ4) with the Pr5−xCo2+xB6-type structure and space group R 3 m, Dy3FeB7 (τ5) with the Y3ReB7-type structure and space group Cmcm, and DyFeB4 (τ6) with the YCrB4-type structure and space group Pbam, at 873 and 1073 K. It is noteworthy that DyFe2B2 (τ2) reported previously in the literature was not found in the present analyses of the measured equilibrated alloys. Finally, based on the experimentally determined results, two isothermal sections of the Dy-Fe-B ternary system at 873 and 1073 K were constructed, providing key experimental data and a theoretical basis for the thermodynamic calculation of this ternary system and the design of high-performance and low-cost Nd-Dy-Fe-B permanent magnets.

The inherent strength-ductility trade-off remains a primary bottleneck for face-centered cubic (FCC) multi-principal element alloys (MPEAs), restricting their broader structural engineering applications. This study introduces a Fe42Ni30Co16Al10Nb2 MPEA featuring a multiscale hierarchical FCC/B2/C15 Laves heterostructure, tailored via multi-step forging and subsequent isothermal annealing. Crucially, the formation of this hierarchical architecture is driven by a unique scale-dependent, dual-directional mutual precipitation mechanism. Specifically, the micrometer-scale primary Laves phase undergoes localized phase separation to precipitate secondary blocky B2 particles, while the sub-micrometer B2 domains simultaneously expel over-saturated solutes to form high-density, intra-granular acicular C15 Laves nano-needles. This precisely controlled thermomechanical processing (TMP) route enables wide-range tuning of the mechanical profile. The HF-700 sample achieves an ultra-high ultimate tensile strength (UTS) of ~1319MPa—a 67.4% improvement relative to the as-cast state. This superior strength is primarily governed by the potent dislocation pinning at the semi-coherent B2/C15 Laves nano-interfaces and the hetero-deformation-induced (HDI) strengthening across the multiscale phase boundaries. In contrast, the HF-800 sample exhibits an optimized performance balance, maintaining a high UTS of ~925MPa while recovering total elongation to ~20%. This investigation provides an effective TMP strategy and fundamental microstructural insights into optimizing the strength-ductility synergy of high-performance FCC-based MPEAs.

SmCo7 phase with a TbCu7-type structure is a promising candidate for high-performance high-temperature permanent magnets due to its high magnetocrystalline anisotropy and high saturation magnetization, but its metastability at room temperature limits practical applications. This work systematically investigates the effect of Ti substitution on phase structure and magnetic properties of SmCo7-xTix (x = 0–0.6) ribbons prepared by melt spinning and subsequent heat treatment. Results show that increasing Ti content suppresses the precipitation of SmCo5 phase and promotes stabilization of TbCu7-type SmCo7 phase in SmCo7-xTix as-cast alloys, and when x ≥ 0.45, SmCo11Ti and Sm2Co7 phases precipitate. After melt spinning at 40 m/s, all the SmCo7-xTix melt-spun ribbons exhibit a single TbCu7-type structure. The intrinsic coercivity (Hcj) first increases and then decreases with Ti content, reaching a maximum of 4.32 kOe at x = 0.45, while the magnetization (σ2T) decreases monotonically. In the wheel speed range of 20–40 m/s, increasing wheel speed refines grains and enhances intergranular exchange coupling, leading to a significant increase in the remanence ratio, which compensates for the decrease in σ2T and results in an upward trend of remanence. After annealing below 700 °C, ribbons retain the single-phase structure, but coercivity decreases continuously with temperature; at 800 °C, TbCu7-type SmCo7 phase decomposes into Sm2Co17 and α-Co phases, causing severe deterioration of hard magnetic properties. The variation of remanence under different wheel speeds and annealing temperatures is governed by competition between the remanence ratio and σ2T. The optimal comprehensive magnetic properties are achieved at x = 0.45 and a wheel speed of 40 m/s. This study reveals the synergistic stabilization mechanism of TbCu7-type SmCo7 phase by Ti substitution and melt spinning, and clarifies the remanence regulation by competition between remanence ratio and σ2T, providing a basis for composition design of high-performance nanocrystalline permanent magnets.

Y2Ti2O7 ceramic is considered a promising microwave absorbing material because of its pyrochlore structure and excellent chemical stability, but its practical application is restricted by low intrinsic dielectric loss and narrow absorption bandwidth. In this work, unlike the vacuum hot-pressing strategy, which may suppress conductivity, this work employed a facile sol-gel method followed by air sintering to fabricate nanostructured Y2-xSrxTi2O7 (x = 0, 0.05, 0.1, 0.15) ceramics. This process enabled effective regulation of the crystal structure and defect states. With increasing Sr doping, the concentration of oxygen-vacancy-related defects and the conductive behavior were effectively modulated. Y1.9Sr0.1Ti2O7 (Sr10) ceramic exhibits a nanostructured network composed of short rod-like nanoparticles and achieves the best microwave absorption performance, delivering a minimum reflection loss of -51.11 dB and a maximum effective absorption bandwidth of 4.63 GHz. The superior performance originates from an optimized synergistic mechanism established by an appropriate concentration of oxygenvacancy-related defects, in which hopping conduction serves as the dominant attenuation pathway, while defect-related and interfacial polarization relaxation play an auxiliary role in regulating the dielectric response and improving impedance matching. Therefore, the optimal performance of Sr10 sample arises from the synergistic balance between attenuation capability and impedance matching, rather than simply from an increase in defect concentration. Furthermore, radar cross-section (RCS) simulations demonstrate that Sr10 sample achieves an RCS reduction of over 33.6 dBsm compared with a perfect electric conductor. This work provides a useful reference for the performance optimization of pyrochlore-structured dielectric absorbing materials.

The phase relationships along the Sm2Co17-Y2Co17 section of the ternary Sm-Y-Co system have been studied by X-ray powder diffraction, scanning electron microscopy, differential thermal analysis and thermogravimetric analysis. The results show that (Sm1-xYx)2Co17 (x = 0.0-1.0) alloys form continuous solid solutions with rhombohedral structure (space group R-3 m). The lattice parameters a, c and cell volumes V of (Sm1-xYx)2Co17 solid solutions decrease linearly with the increase of Y. And the congruent melting temperature of (Sm1-xYx)2Co17 alloys increases gradually when Y content increases, while the Curie temperature decreases linearly. The allotropic transformation reaction beta-(Sm, Y)2Co17 -><-alpha-(Sm, Y)2Co17 has been confirmed, although its transition temperature was unclear. Combined with the test data, the tentative vertical section phase diagram of Sm2Co17-Y2Co17 in the ternary Sm-Y-Co system has been constructed.

Solidification microstructure and phase equilibria of the Sm-Co-Ti ternary system were investigated through experimental study and thermodynamic calculation. The solidification microstructure of several Sm-Co-Ti as-cast alloys was investigated experimentally by electron probe microanalysis (EPMA). Based on the experimental data from this work and the literature, thermodynamic calculation of the Sm-Co-Ti ternary system was performed using the CALPHAD method together with the prior assessments of the Sm-Co, Co-Ti and Sm-Ti binary systems. The calculated isothermal section and liquidus projection for this ternary system demonstrate the good agreement with the reported experimental data. Solidification microstructure of Sm-Co-Ti alloys was analyzed through thermodynamic calculation using the Scheil-Gulliver non-equilibrium model. The excellent agreement between the simulated results and experimental observations indicates that thermodynamic parameters of the Sm-Co-Ti ternary system obtained in this work are reasonable, which would provide a critical foundation for developing a reliable thermodynamic database of multicomponent Sm-Co-based permanent magnets with transition metals.

The effects of Ti/Zr substitution, annealing temperature, annealing time, and wheel speed on the phase evolution and magnetic properties of YCo12-xTix (x = 0.9, 1.2, 1.5, 1.8, 2.1, and 2.4) and CeCo12-zTiz (z = 1.3, 1.4, 1.5, 1.6, and 1.7) melt-spun ribbons were systematically investigated using scanning electron microscopy, X-ray diffraction, and vibrating sample magnetometer. The results demonstrate the following: (1) For YCo12-xTix alloys, increasing Ti content stabilizes a single-phase ThMn12-type structure at x = 1.8, with melt-spun ribbons (35 m/s) exhibiting optimal magnetic properties (H-cj = 0.37 kOe, B-r = 3.03 kGs, mu M-0(s) = 6.43 kGs). Excess Ti (x > 1.8) triggers secondary phases Co2Ti(h) and YCo3, degrading their magnetic performance. Zr substitution (Y0.75Zr0.25Co10.2Ti1.8) stabilizes the ThMn12 structure, but enhances the formation of Co2Ti(h). (2) Annealing Y0.75Zr0.25Co10.2Ti1.8 ribbon at 400 degrees C for 30 min optimizes magnetic performance (H-cj = 0.69 kOe, B-r = 2.71 kGs, mu M-0(s) = 5.47 kGs) by balancing crystallinity and grain boundary density. Prolonged annealing (>1 h) or higher temperatures (600-800 degrees C) reduces H-cj due to grain coarsening and excessive precipitation of Co2Ti(h). (3) For CeCo10.7Ti1.3 (z = 1.3) and CeCo10.6Ti1.4 (z = 1.4) ribbons, a wheel speed of 30 m/s maximizes the 1:12 phase fraction in a nanocrystalline/amorphous composite, achieving peak performance (H-cj = 0.30/0.22 kOe, mu M-0(s) = 8.20/7.69 kGs). Low speeds (20-25 m/s) yield coarse grains and low H-cj, while high speeds (35-40 m/s) increase amorphous content, disrupting magnetic order. Optimal magnetic properties of YCo12-xTix ribbons with x = 1.8 annealed at 400 degrees C/30 min as well as CeCo12-zTiz ribbons with z = 1.3 (30 m/s wheel speed) were realized, providing insights for designing rare-earth cobalt-titanium magnetic materials.

In this study, the solid-state reaction method was employed to first investigate the pseudo-binary phase equi-librium of the 203-Fe2O3 system, followed by a comprehensive exploration of the phase equilibrium of the Pr2O3-BaO-Fe2O pseudo-ternary system at 1300 degrees C. Furthermore, the solid solution behavior of this system within the 1300 C isothermal region was systematically analyzed. The results demonstrate that this isothermal region consists of eight two-phase equilibrium regions, eight three-phase equilibrium regions, and a single quaternary compound, Ba Fe Pr2015. Notably, this quaternary compound exhibits both antiferromagnetic properties and outstanding microwave absorption performance: at a matching thickness of 2 mm, the minimum reflection loss (BLmin) reaches -32.2 dB, accompanied by a maximum effective absorption bandwidth (EAB) of 3.8 GHz.

This paper introduces a method to enhance the magnetic properties and corrosion resistance of Nd-Fe-B regenerated magnet by incorporating low melting point heavy rare earth alloys at the grain boundaries. Therefore, the effects of Tb2Fe12Ga5 alloy with low melting point on the magnetic properties and corrosion resistance of Nd-Fe-B regenerated magnet under different addition levels were studied. Meanwhile, the coercivity enhancement and corrosion inhibition mechanism were systematically analyzed and explained through the microstructure changes. The waste Nd-Fe-B particles were blended with 3 wt% Tb2Fe12Ga5 powder to fabricate Nd-Fe-B regenerated magnet with the coercivity (Hcj) of 18.61 kOe, remanence (Br) of 12.51 kGs, and maximum energy product ((BH)max) of 38.63 MGOe, reaching performance recovery rates of 110.4%, 100.2%, and 101.1%, respectively, of the original magnets. The corrosion resistance of the regenerated magnets has also been significantly enhanced compared to the original magnets in a simulated seawater environment. The corrosion potential (Ecorr) measured increased from −1.175 V to −1.15 V, and the corrosion current (Icorr) decreased from 100.30 μA/cm2 to 61.64 μA/cm2 when 3 wt% Tb2Fe12Ga5 is added. Meanwhile, the regenerated magnet doped with Tb2Fe12Ga5 exhibited excellent mechanical properties, attributed to its optimized microstructure. Above findings may spur progress towards achieving large-scale production and reducing production costs, providing a potential industrialization solution for the green and efficient recovery of waste Nd-Fe-B magnet

Balancing dielectric attenuation and impedance matching is essential for developing efficient MXene-based EMW absorbers because an excessively developed conductive network may deteriorate impedance matching and hinder electromagnetic wave penetration. Herein, Ti3C2Tx MXene/Y2O3/C composites were prepared through in situ solvothermal assembly followed by pyrolysis. By increasing the Ti3C2Tx MXene feed fraction, the dielectric response and impedance-matching behavior of the composites were systematically regulated. Structural analyses confirmed the formation of crystalline Y2O3, carbonaceous domains, and MXene-based heterostructures with mesoporous features. The composites exhibited composition-dependent and non-monotonic absorption behavior. MY-3(Nominal MXene-to-precursor feed ratios of 2:5) composite delivered the strongest absorption intensity with a minimum RL of −49.4dB, while MY-4(Nominal MXene-to-precursor feed ratios of 1:2) composite achieved the broadest EAB of 7.2GHz. The enhanced absorption performance is attributed to the regulated conductive network, interfacial polarization at MXene/Y2O3/C heterointerfaces, dipole polarization from polar bonds and oxygen-containing groups, and improved impedance matching. Radar cross-section simulations further verified the scattering suppression capability of the optimized coatings. This work demonstrates that Y2O3/C-assisted dielectric regulation is an effective strategy for improving broadband absorption in MXene-based dielectric absorbing materials.

Phase equilibria and solidification behavior of the Sm–Co–Cu ternary system were studied by using scanning electron microscope with energy dispersive spectroscopy (SEM–EDS) and X-ray diffraction (XRD). The results of phase equilibria reveal that ten binary intermetallic compounds including SmCo2, SmCo3, Sm2Co7, Sm5Co19, SmCo5, Sm2Co17, SmCu2, SmCu4, SmCu5, and SmCu6 were observed, and the ternary intermetallic compounds were not detected. The continuous solid solution phase Sm(Co, Cu)5 is formed from the respective SmCo5 and SmCu5. The solubility of Cu in SmCo2, SmCo3, Sm2Co7, and Sm2Co17 and that of Co in SmCu2 and SmCu4 were determined. Three isothermal sections at 873 K, 1073 K, and 1273 K were established. Meanwhile, solidification microstructures of Sm10.5Co89.5−xCux as-cast alloys were examined. Furthermore, on the basis of the present and earlier experimental results, thermodynamic calculation of the Sm–Co–Cu ternary system was carried out using the CALPHAD method. The calculated isothermal sections and vertical sections in this ternary system are in good agreement with the experimental results. Finally, solidification processes of several Sm–Co–Cu as-cast alloys were simulated using the Scheil–Gulliver module with thermodynamic parameters. The simulated results are satisfactorily consistent with the experimental solidification microstructure. It indicates that thermodynamic parameters of this ternary system obtained in this work are self-consistent and reasonable. The present parameters would provide the proper foundation to develop a thermodynamic database of multi-component Sm–Co-based magnetic alloys, which is valuable information for exploring high-performance and low-cost Sm–Co–Cu-based permanent magnets.

Enhancing the utilization of abundant rare earth elements to produce Nd-Fe-B based magnets with superior permanent magnetic properties remains a significant research focus in the field of rare earth permanent magnets. In this study, we propose an effective approach to significantly improve the coercivity of Nd,Ce-Fe-B-Ga ribbons. Ribbons with nominal compositions of [(1–x)(Nd0.5Ce0.5)11.76Fe82.35B5.88 + xNd30Fe65Ga5] (at%; x = 0, 0.1, 0.2, and 0.3) were fabricated via melt-spinning. Hysteresis loops at ±2 T reveal obvious exchange bias phenomena in all samples except for x = 0, which originates from the exchange coupling effect between the ferromagnetic (FM) phase and the antiferromagnetic (AFM) phase. Under an applied field of ±5 T, the coercivity increases progressively from 6.55 kOe (x = 0) to 18.98 kOe (x = 0.3). Specifically, the sample of x =0.1, where Ce accounts for 38.96 at% of the total rare earth content, achieves a coercivity of 14.46 kOe. The absolute values of the temperature coefficients of remanence (α) and coercivity (β) decrease from 0.420%/K (x = 0) to 0.334%/K (x = 0.2) and from 0.708%/K (x = 0) to 0.439%/K (x = 0.2), respectively. The transmission electron microscopy (TEM) characterization shows that in the Ga-free ribbons (x = 0), grains of the main phase RE2Fe14B are continuously surrounded by a thin RE-rich grain boundary (GB) phase. With Ga addition (x = 0.3), the continuous RE-rich GB phase disappears and large-sized triple junction phases form, which are composed of the RE-rich phase and the RE6Fe13Ga phase. Henkel plots further confirm the strong intergranular exchange coupling effect. Therefore, we propose a coercivity enhancement mechanism, namely, the reversal of magnetic domains is pinned through the exchange coupling effect between the AFM phase and the FM phase, thereby enhancing the coercivity of the magnet.

Regulating the density of effective carrier storage traps is critical for improving the energy-storage capability and emission intensity of mechanoluminescent (ML) materials. However, existing ML materials commonly suffer from insufficient intrinsic traps, limited carrier storage capacity, and weak luminescent response, which restrict their further development for high-performance applications such as intelligent sensing, stress recording, and information anticounterfeiting. Herein, we propose a Yb3+-induced trap engineering strategy to construct more effective carrier storage traps in CaGeO3:Mn2+ through the aliovalent substitution of Yb3+ for Ca2+, thereby improving the ML performance of the material. X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), and thermoluminescence (TL) results support the regulatory effect of Yb3+ doping on the local structural environment and the formation of carrier storage traps. XPS analysis reveals a systematic evolution of the oxygen-vacancy-related components with increasing Yb3+ concentration. The pronounced shift of the g factor in the EPR spectra indicates that the local crystal-field environment around Mn2+ is affected and suggests that Yb3+ doping may induce changes in the local coordination environment, providing structural evidence for the formation of carrier storage traps. TL analysis further supports the role of Yb3+ doping in promoting the formation of effective carrier storage traps and improving the trap energy-storage capability of the material. With the enhanced trap energy-storage capability, CaGeO3:Mn2+,Yb3+ exhibits significantly improved ML performance. This study clarifies the important role of Yb3+-induced trap engineering in enhancing ML performance and provides guidance for the design of high-performance ML materials and their applications in information security and physical anticounterfeiting.

A comprehensive CALPHAD-based investigation of the TM-RE (TM = Ti, V, Cr; RE = rare-earth elements) binary systems was conducted to establish a self-consistent and SGTE-compatible thermodynamic dataset for the subsequent development of multicomponent alloy databases. Available experimental phase equilibria and thermodynamic data for the TM-RE binary systems were critically evaluated. For fourteen TM-RE binary systems with reliable previous assessments, the reported thermodynamic parameters were adopted after checked consistently. In contrast, twenty-three TM-RE binary systems exhibiting incomplete data, inconsistent thermodynamic trends, or non-physical behaviors were reassessed and optimized to ensure parameter consistency and reliability. Systematic variations in phase equilibria and thermodynamic properties of the TM-RE (TM = Ti, V, Cr; RE = rare-earth elements) binary systems were identified. With the exception of the TM-Ce binary systems, all the TM-RE binary systems exhibit positive liquid mixing enthalpies and positive deviations from ideal activities, indicating predominantly repulsive atomic interactions between TM and RE elements. Furthermore, the magnitude of the liquid mixing enthalpy decreases with increasing RE atomic number, leading to a gradual transition from liquid miscibility gaps in light RE-TM binary systems to eutectic-type phase diagrams in heavy RE-TM binary systems. The resulting self-consistent thermodynamic dataset provides a reliable basis for thermodynamic extrapolation to ternary and higher-order TM-RE-based alloy systems.

Constructing multi-component composites with optimal component ratios is a crucial approach to enhance their electromagnetic wave absorption efficiency and achieve broadband response. However, the control of component ratios and realizing synergistic broadband absorption performance in the multi-component composites remains significant challenges. Herein, a solvothermal method was employed to synthesize metal–organic framework (MOF) precursors containing rare earth (RE) Y3+ and magnetic Ni2+ ions, followed by high-temperature pyrolysis to successfully prepare structurally stable Y2O3/Ni/C ternary composites with excellent microwave absorption properties. The microstructure morphology as well as interfaces and defects of Y2O3/Ni/C composites were regulated by adjusting the concentration of Y3+. When the molar ratio of Y3+/Ni2+ is 1:1, the Y2O3/Ni/C composite exhibited a maximum effective absorption bandwidth of 6.72 GHz at a matching thickness of 2.2 mm. When the molar ratio of Y3+/Ni2+ increases to 2:1, larger uniform spheres are formed in the Y2O3/Ni/C composite, delivering a minimum reflection loss of − 53.46 dB at 5.12 GHz. By adjusting the thickness, strong broadband electromagnetic wave absorption of Y2O3/Ni/C composites was achieved across the X, C, and Ku bands. These high performances are mainly ascribed to the synergistic effects of multiple components, enabling outstanding impedance matching and efficient energy dissipation. The present findings would provide a new strategy for designing RE-MOF derivatives with tunable and efficient electromagnetic wave absorption performance.

Functional core–shell heterostructures serve as key components of electromagnetic wave absorbers, enabling the effective integration of advantageous properties from multiple materials. Through synergistic interactions among their components, these structures significantly enhance overall absorption performance. A ZnS@CoNi composite with a core–shell structure was successfully synthesized via a straightforward two-step hydrothermal method. Subsequently, the effects of CoNi addition on the microstructure, phase composition, and absorption properties of the composite were systematically investigated. Research results indicate that with a CoNi loading of 75

In response to the urgent need for lightweight and efficient electromagnetic wave–absorbing materials, this study successfully prepared Pr2O3/C novel composites by hydrothermal synthesis combined with an H2/Ar protective atmosphere calcination process. By comparing the different calcination temperatures, it was found that the samples treated at 800 °C exhibit the best wave–absorbing properties. The minimum reflection loss (RL) of –52.72 dB is achieved at a thickness of 3 mm, which corresponds to an effective absorption bandwidth (EAB) of 3.44 GHz, covering the key frequency band of the X–band. Mechanistic studies show that the excellent performance stems from a multi–mechanism synergy dominated by dielectric loss, including interfacial polarization, resistive loss and dipole polarization effects. The radar cross–section (RCS) simulation further confirms that the reflective intensity of the ideal conductor surface coated with the material is significantly reduced, highlighting its potential application in stealth coating. This study provides a new idea for the design of broadband strongly absorbing materials through the rare earth oxide–carbon matrix composite strategy.

Ion doping can significantly enhance microwave absorption performance. In this paper, powders of Sr1-xGdxMnO3 (x = 0, 0.02, 0.04, 0.06) were synthesized via a simple sol-gel process. Comprehensive characterization elucidated the phase evolution, microstructure, valence states, magnetic properties, and electromagnetic attenuation mechanisms of Gd-doped SrMnO3. With the incorporation of Gd3+, the crystal structure of Sr1-xGdxMnO3 transitions from hexagonal to cubic. The crystal lattice develops substantial defects, while the resulting valence imbalance drives the reduction of Mn4+ to Mn3+. These synergistic effects enhance multi-polarization phenomena, including defect polarization and charge polarization. Notably, the addition of an appropriate amount of Gd ions to the material can effectively adjust its electromagnetic parameters and optimizes impedance matching. Among the synthesized samples, Sr0.94Gd0.06MnO3 exhibits optimal microwave absorption performance, achieving a minimum reflection loss of-36.6 dB at 9.84 GHz and an effective absorption bandwidth of 3.04 GHz at a thickness of 2.2 mm. Additionally, an effective absorption bandwidth of 4.0 GHz is achieved for x = 0.02 at a thickness of 1.6 mm. These results not only indicate that Gd3+ doping significantly enhances the absorbing properties of SrMnO3 but also provide valuable theoretical guidance for the design of high-efficiency electromagnetic wave absorption materials in future research.