Thermal evolution of microstructure and magnetic properties of melt-spun iron-chromium-vanadium-manganese-phosphorus-carbon-silicon (at.%) alloy

Melt-spun Fe_73.5Cr₅V₂Mn_0.5P ₁₃C₅Si₁ (at.%) alloy produced from ferrophosphorus waste was extensively evaluated by microstructure, thermodynamics and kinetics of crystallization and magnetic properties as a potential candidate for distribution transformer cores. This attempt to reclaim waste was significant in that less environmental damage would result from waste disposal, less mining would be needed and general reduction of material consumption would result. And, of course, the ultimate cost would be economical.; The changes in the microstructure and magnetic properties of melt-spun Fe_73.5Cr₅V₂Mn_0.5P₁₃C ₅Si₁ alloy upon heat treatments were systematically investigated. Thermal evolution of structural transformations was monitored by differential thermal analysis (DTA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and transmission electron microscopy (TEM). Thermal evolution of magnetic properties was studied by a vibrating sample magnetometer (VSM).; It was found that crystallization of melt-spun Fe_73.5Cr ₅V₂Mn_0.5P₁₃C₅Si₁ alloy occurred at around 460°C and proceeded as a two-stage process. The final equilibrium phases (α-Fe and Fe₃P) were formed via intermediate stage of Frank-Kasper type metastable phase (α-Mn type, a = 0.874 ± 0.004 nm) formation. The structure relationship in terms of short-range order between the as-spun metallic glass, Frank-Kasper type metastable phase and equilibrium crystals were found to be related to the thermal stability and crystallization behavior of melt-spun Fe_73.5Cr ₅V₂Mn_0.5P₁₃C₅Si₁ alloy. In addition, fine-grained α-Fe embedded in an amorphous matrix structure was obtained below the onset of crystallization.; It was also found that both the as-spun amorphous alloy and the fine-grained α-Fe structure achieved by annealing well below the crystallization temperature demonstrated great potential as promising soft magnetic materials. However, these soft magnetic properties were greatly degraded upon crystallization. Saturation magnetization dropped sharply upon metastable phase formation, and coercivity and retentivity increased drastically upon equilibrium phase formation.; Thus, the microstructure and magnetic properties of melt-spun Fe _73.5Cr₅V₂Mn_0.5P₁₃C ₅Si₁ alloy could be controlled by the annealing temperature, which could serve as a guideline to a suitable heat treatment that would optimize its magnetic properties.