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A new way to prepare soft magnetic materials with high magnetization was proposed using the phase transition decomposition theory, and the saturated magnetic polarization intensity of the ribbons designed based on the composition of FeCo-type α 1 phase reaches 1.88 T after melt-spinning at 40 m/s. The ingots and as-spun ribbons comprise FeCo-type main and AlNi-type minor phases. During melt-spinning, the main phase grows into columnar grains along the thickness direction of the as-spun ribbons. AlNi phase distributes at the grain boundaries of the columnar grains, and its content reduces from 38.8 wt% to 22.0 wt%, thus forming a novel core@shell columnar structure. The micromagnetic simulation results revealed that the soft magnetic properties of as-spun ribbons with AlNi phase at the grain boundaries are superior to that of the nonmagnetic grain boundary phase and grain boundary-free models. The weakly magnetic AlNi phase promotes the coordinated rotation of the magnetic moments of the ferromagnetic FeCo phase within the grains, thus reducing the coercivity of the ribbons; the columnar grain structure improves the remanence of the as-spun ribbons. This FeCo@AlNi core-shell columnar structure provides a new idea for preparing soft magnetic materials with high magnetization. [Display omitted] • Proposed a new way to prepare soft magnetic materials with high magnetization. • A novel core@shell columnar structure is formed by phase transition decomposition. • The weakly magnetic AlNi shell coating the ferromagnetic columnar FeCo cores. • Micromagnetic simulation reveals the magnetic mechanism. • The AlNi shell phase promotes the coordinated rotation of the adjacent FeCo grains. [ABSTRACT FROM AUTHOR]

The Fe–15Ni–3Al–1Ti ribbons are produced by melt-spinning the annealed ingots at 10–40 m/s. The annealed ingots consist of Fe 3 Ni grains and α-Fe-type grain boundary phase, forming a columnar grain microstructure in the vertical direction and getting the maximum saturation magnetic polarization (J s) of 1.88 ± 0.03 T in the cross-section. Before and after the annealing, the ribbons form a cellular structure composed of the Fe 3 Ni intragranular phase and γ-(Fe, M), Fe 7 Ni 3 , or α-(Fe, M) cell boundary phases. Formation of enhanced <100> orientation is the primary mechanism for obtaining a high J s of 2.35 ± 0.07 T in the ribbons. The grain and grain boundary size of the ribbons is reduced by the phase transformation induced by annealing at 600 °C. The phase transformation processes of the ribbons before and after annealing are as follows: L → γ → m e l t − s p u n Fe 3 Ni + γ 1 → a n n e a l e d Fe 3 Ni + Fe 7 N i 3 when melt-spinning at a speed of 10–25 m/s, and L → γ → m e l t − s p u n Fe 3 Ni + Fe 7 N i 3 → a n n e a l e d Fe 3 Ni + α − (Fe , Ni) at 40 m/s. Finally, the multiscale microstructure evolution models are used to summarize the phase transformation process of the alloys. [ABSTRACT FROM AUTHOR]