Experimental determination of phase diagram involving silicides in the Fe-Si binary system

• Published in: Journal of alloys and compounds Vol. 919; p. 165810
• Main Authors: Han, K., Saito, M., Xia, J., Ohnuma, I., Kainuma, R.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 25.10.2022; Elsevier BV
• Subjects: Binary system; Binary systems; C. phase diagrams; D. electron emission spectroscopy; D. thermal analysis; Intermetallic compounds; Intermetallics; Iron silicide; Liquidus; Order-disorder transformations; Phase diagrams; Phases; Silicon; Solidus; Thermal analysis; Intermetallics; C. phase diagrams; D. electron emission spectroscopy; D. thermal analysis
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2022.165810

The phase diagram of the Fe-Si binary system was precisely determined using FE-EPMA/WDS and thermal analysis of DSC. It was confirmed that the concentration ranges of the β-Fe2Si and ζα-FeSi2 phases are slightly narrower and shifted toward higher Fe concentrations compared with the literature, and the other iron-silicide phases have low but certain concentration ranges less than 1 at%. The A2/B2/D03 order-disorder transition and Curie temperatures in the BCC phases exhibited concentration dependences consistent with those temperatures reported by Meco and Napolitano, and the Curie temperatures of the α”-Fe3Si (D03) alloys deviated higher from the extrapolated values of the α-Fe (A2) phase with increasing Si content and bent at the stoichiometric composition of 25 at%Si. Invariant reaction temperatures were mostly coincident with those of the phase diagram in the literature, except for the peritectoid temperature of the η-Fe5Si3 phase, whereas a small discrepancy was revealed in the solidus and liquidus lines. •Phase equilibria of Fe-Si alloys were experimentally determined, and the phase diagram of the Fe-Si binary system was critically revised.•Effects of the chemical ordering in the A2/B2/D03 bcc phases on the solidus and liquidus boundaries as well as on the Curie temperature (TC) were determined precisely.•The temperature of the peritectoid reaction, β-Fe2Si+ ε-FeSi→η-Fe5Si3, was confirmed to be 30 °C higher than the reported one in the literature, whereas the temperatures of the other invariant reactions were almost coincident with each other within± 7 °C difference.•The concentration ranges of the β-Fe2Si and ζα-FeSi2 phases were slightly narrower and shifted toward higher Fe concentrations compared with the literature, and the other iron-silicide phases had low but certain concentration ranges less than 1 at%.