Experimental investigation of phase equilibria in the Fe–Nb–Si ternary system

•Three isothermal sections of the Fe–Nb–Si system were experimentally determined.•Some different phase relationships are confirmed in this work.•The solubility of Si in the εNbFe2 phase is about 27.5 at.%, remaining unchanged with the temperature range from 1200 °C to 1000 °C.•The solubility of Si in the μFeNb phase decreases from 14.7 at.% to 10.0 at.% with decrease of temperature from 1200 °C to 1000 °C.

The phase equilibria of the Fe–Nb–Si ternary system were investigated by electron probe microanalyzer (EPMA), back scattered electron (BSE), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) on the equilibrated alloys. In this study, three isothermal sections of the Fe–Nb–Si ternary system at 1200 °C, 1100 °C and 1000 °C were respectively determined and six ternary compounds were confirmed. The obtained experimental results show that there are large solubilities of Si in the εNbFe2 and μFeNb phases. The newly determined phase equilibria of the Fe–Nb–Si system will provide useful information for silicon steels development.