Xingjie Jia

Effects of Mo addition on thermal stability and magnetic properties of a ferromagnetic Fe75P10C10B5 metallic glass

The effects of Mo content on the thermal stability, glass-forming ability (GFA), magnetic and mechanical properties of Fe75−xMoxP10C10B5 (x = 0–10) metallic glasses were investigated. The stabilization of supercooled liquid and GFA were significantly enhanced by addition of Mo. Although the saturation magnetization (Is) of the alloys reduced with increasing Mo content, the coercive force (Hc) decreased. The metallic glasses with x = 2.5–7.5 exhibit low glass transition temperature of 733–749 K, large supercooled liquid region of 61–96 K, and high GFA with critical fully glassy sample diameters of 1.5–3.0 mm. They also possess rather high Is of 0.81–1.11 T, low Hc of 2.07–4.87 A/m, high Vickers hardness of 860–992, high compressive yield strength of over 3000 MPa with a distinct plastic strain.

Structure and soft magnetic properties of Fe-Si-B-P-Cu nanocrystalline alloys with minor Mn addition

Addition of minor Mn effectively improves the amorphous-forming ability and thermal stability of the Fe85Si2B8P4Cu1 alloy. With increasing the Mn content from 0 to 3 at.%, the critical thickness for amorphous formation and onset temperature of the primary crystallization increase from 14 μm and 659 K to 27 μm and 668 K, respectively. The fine nanocrystalline structure with α-Fe grains in size (D) of < 20 nm was obtained for the annealed amorphous alloys, which show excellent soft magnetic properties. The alloying of Mn reduces the coercivity (Hc) by decreasing the D value and widens the optimum annealing temperature range for obtaining low Hc, although the saturation magnetic flux density (Bs) is decreased slightly. The Fe83Mn2Si2B8P4Cu1 nanocrystalline alloy possesses fine structure with a D of ∼17.5 nm, and exhibits a high Bs of ∼1.75 T and a low Hc of ∼5.9 A/m. The mechanism related to the alloying effects on the structure and magnetic properties was discussed in term of the crystallization activation ...

Effects of alloying elements on thermal stability, glass-forming ability and soft magnetic properties of Fe-P-C-B metallic glasses

Fe-based bulk metallic glasses (BMGs) are attractive for the engineering applications as functional materials because of their excellent soft magnetic properties, very high strength, viscous flow workability in the supercooled liquid region (ΔT_x = T_x-T_g, T_g: glass transition temperature; T_g: crystallization temperature), and low material cost [1]. Recently, the thermoplastic processing has been expected to make highly functional micro-/nano-parts and electromechanical devices on the soft magnetic Fe-based BMGs by suing the viscous flow workability [1,2]. The suitable BMGs for thermoplastic processes have to possess simultaneously low T_g, large ΔT_x, and high glass-forming ability (GFA). From a processing point of view, it is desirable to possess a large ΔT_x which gives access to a low forming viscosity, which in turn facilitates thermoplastic forming. A low T_g implies a low processing temperature since it facilitates processing [2]. In addition, a low T_g can prevent the reaction of the metallic glasses with mold materials. However, most of the Fe-based BMGs with good soft magnetic properties exhibited high T_g, small ΔT_x, low GFA or high viscosity in the supercooled liquid state, which hinder their thermoplastic formability. In this work, with the aim of developing new ferromagnetic Fe-based BMGs with low T_g, large ΔT_x and high GFA for the thermoplastic processing, we investigated the effect of alloying additions on the thermal stability, GFA, magnetic properties of the Fe-P-C-B metallic glasses with low T_g.

The Effect of Pt Addition on the Structure and Magnetic Properties of Melt-Spun Fe80–xPtxB20 Alloys

The structure and magnetic properties of the melt-spun Fe80–xPtxB20 (x = 0 – 20) alloys have been investigated. The amorphous phase was obtained for the alloys with x = 0 and 5, while the mixed structure consisting of amorphous and fcc-FePt phases was formed for the alloys with x = 10, 15 and 20. The annealed alloys consist of α-Fe + Fe3B phases for x = 0 and 5, Fe3B + Fe2B + fcc-FePt phases for x=10, and Fe2B + fcc-FePt + L10-FePt phases for x = 15 and 20, respectively. The alloys with x = 15 and 20 exhibited hard magnetic characterization after annealing. The coercivity increased with increasing Pt content.