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Nanocrystalline powders, characterized by a biphasic amorphous nanocrystalline structure, demonstrate outstanding soft magnetic characteristics, including reduced coercivity (H_c), enhanced effective permeability (μ_e), and increased resistivity. However, their high hardness, poor formability, and significant core loss (P_cv) restrict their use in high-performance molded inductors. In this study, FeSiBCuNb/FeSiAl nanocrystalline soft magnetic composites (NSMCs) were fabricated, and the influence of varying the FeSiAl concentration on the microstructure, density, and soft magnetic characteristics of NSMCs was investigated. Then, the underlying mechanisms of these effects were explained. The results demonstrate that FeSiAl exhibits apparent deformation following compression, effectively filling the air gap between the FeSiBCuNb powder particles, thereby enhancing coupling among the magnetic particles. Consequently, the density of the NSMCs was enhanced, leading to a significant improvement in their overall soft magnetic properties. When 50 wt.% FeSiAl is added, the NSMCs display outstanding magnetic properties, including a low H_c of 4.36 Oe, a high μ_e of 48.7, a low P_cv of 119.35 kW/m³ at 50 mT and 100 kHz, and a high DC-bias performance of 73.29% at 100 Oe. Compared to NSMCs without FeSiAl, μ_e increased by 59.4% and P_cv decreased by 66.1%. Meanwhile, the incorporation of ultrafine FeSiAl powder was found to significantly improve the material properties, as the deformable FeSiAl particles effectively fill interparticle gaps during compaction, enhancing density and magnetic coupling. The 50 wt.% FeSiAl composition demonstrated exceptional properties. These advances address critical challenges in high-frequency power electronic applications and provide a practical material solution for next-generation power electronics. Full article

Building nanocrystalline–amorphous biphase nanostructure has recently emerged as an advanced route to improve radiation tolerance, as the nanocrystalline–amorphous interface is expected to enhance the sink efficiencies of helium atoms. However, the structure evolution and degradation mechanisms during helium ion implantation in nanocrystalline–amorphous biphase films are still unclear. This study aimed to further understand these mechanisms through in situ observation of nanocrystalline–amorphous TiAl biphase films deposited via magnetron sputtering in a helium ion microscope. Results demonstrate that during the helium implantation process (the final fluence was 4 × 10¹⁷ ions cm⁻²), a partial swelling occurred in the implantation region without blisters, cracks, or exfoliation on the surface. The AFM and TEM results revealed that the partial bulge originated from the differential in the swelling rate between the amorphous and grain areas during helium ion implantation. These findings offer promising insights into designing radiation-tolerant materials for advanced nuclear reactors. Full article

Herein, the effect of Ni-doping amount on microstructure, magnetic and mechanical properties of Fe-based metallic microwires was systematically investigated further to reveal the influence mechanism of Ni-doping on the microstructure and properties of metallic microwires. Experimental results indicate that the rotated-dipping Fe-based microwires structure is an amorphous and nanocrystalline biphasic structure; the wire surface is smooth, uniform and continuous, without obvious macro- and micro-defects that have favorable thermal stability; and moreover, the degree of wire structure order increases with an increase in Ni-doping amount. Meanwhile, FeSiBNi2 microwires possess the better softly magnetic properties than the other wires with different Ni-doping, and their main magnetic performance indexes of M_s, M_r, H_c and μ_m are 174.06 emu/g, 10.82 emu/g, 33.08 Oe and 0.43, respectively. Appropriate Ni-doping amount can effectively improve the tensile strength of Fe-based microwires, and the tensile strength of FeSiBNi3 microwires is the largest of all, reaching 2518 MPa. Weibull statistical analysis also indicates that the fracture reliability of FeSiBNi2 microwires is much better and its fracture threshold value σ_u is 1488 MPa. However, Fe-based microwires on macroscopic exhibit the brittle fracture feature, and the angle of sideview fracture θ decreases as Ni-doping amount increases, which also reveals the certain plasticity due to a certain amount of nanocrystalline in the microwires structure, also including a huge amount of shear bands in the sideview fracture and a few molten drops in the cross-section fracture. Therefore, Ni-doped Fe-based metallic microwires can be used as the functional integrated materials in practical engineering application as for their unique magnetic and mechanical performances. Full article