Experimental determination of phase diagram at 450 °C in the Zn-Fe-Al ternary system

Phase equilibria in multi-phase Zn-Fe-Al alloys were experimentally measured using a field-emission electron probe micro-analyzer for alloy samples, and a precise iso-thermal phase diagram at 450 degrees C in the entire composition range of the Zn-Fe-Al ternary system, except for the Fe-rich corner, was determined. The ternary solubility ranges of the Gamma-Fe4Zn9, Gamma(1)-Fe21.2Zn80.8, delta(1k)-FeZn7, and zeta-FeZn13 on the Fe-Zn side and of the zeta-FeAl2, eta-Fe2Al5, and theta-Fe4Al13 on the Fe-Al side were consistent with the latest corresponding binary data, whereas no delta(1p)-Fe13Zn126 phase was detected. The single-phase region of the Gamma(2)-Fe8Zn87Al4 ternary intermetallic compound phase is significantly narrower than that reported in the previous studies. The solubility of Fe in the liquid phase increased consistently and continuously from the value in the Zn-Fe binary system (0.6 at.%) up to 1.2 at.% at 31 at.% Al with increasing Al content. In the Al-rich portion of the phase diagram at 450 degrees C, the Fe(Al, Zn)(6) intermetallic compound phase was newly discovered, and confirmed to be an isomorph extended from the FeAl6 phase which is metastable in the Fe-Al binary system. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

Phase equilibria in multi-phase Zn-Fe-Al alloys were experimentally measured to determine a precise iso-thermal phase diagram at 450 degrees C. The solubility ranges of various intermetallic compound phases on both Fe-Zn and Fe-Al sides were consistent with binary data, with the discovery of a new Fe(Al, Zn)(6) intermetallic compound phase in the Al-rich region at 450 degrees C.