Aspectos termodinâmicos e microestruturais da precipitação de fases secundárias em Fe-Si 3% bifásico

Abstract

The magnetic properties of electrical steels are affected by precipitation of secondary phases. The precipitates can work as a key controlled requirement as part of the manufacturing process or as an unwanted harmful residual in the final product. In this work, secondary phases (precipitates) of high permeability grain oriented electrical steels (HGO) were studied. The samples were encapsulated in a vacuum sealed quartz tube and annealing was carried out in two temperatures followed by quenching in water. These experiments were realized at different temperatures during 2h of soaking. Carbon replicas were used to analyze the samples through energy dispersive spectroscopy in X-ray (EDX) in a transmission electron microscope (TEM) and also bulk samples was analyzed in scanning electron microscope (SEM). In addition, we used electrochemical extraction and optical emission spectroscopy inductively coupled plasma (ICP-OES) to study the chemical composition of secondary phases. Additionally, we also applied computational resources to access the multi-component phase equilibrium, and phase transformation for the system, also compare the results of the experiments mentioned with those predicted by the CALPHAD method used in computational thermodynamic software, Thermo-Calc .