Aluminium – Iron – Silicon

Abstract

The system contains many technologically important alloys, so the phase equilibria of the ternary system have been reviewed a number of times [34Fue, 43Mon, SOGme, 52Han, 59Phl, 68Dri, 81Riv, 81Wat, 85Riv]. The system is characterized by a number of ternary phases, and at least nineteen ternary invariant reactions during solidification which make it difficult to establish the phase equilibria of the system. The complexity is further supplemented by supercooling, incomplete reactions and metastabi.lity. Earlier works by [23Dix, 23Han, 23Wet, 24Fus, 34Roe, 41Pan] were mostly on the observation of the microstructure of dilute Al alloys. The most comprehensive study of the phase equilibria of the entire system was performed by [40Tak]. The Al corner has been studied rather extensively [27Gwy, 33Nis, 36Jae, 37Ura., 43Phi, 51Now, 67Mun], and is believed to be fairly well undetstood. [40Tak] used electrolytic iron, pure aluminium and metallic sili.con (unspecified purity). Over 150 ternary alloys were prepared using master alloys of selected compositions in an arc furnace under hydrogen atmosphere with NaCl as flux on the molten surface of the alloys. Temperature was measured by a ft/Pt-Rh thermocouple which was cal.ib,/-ated against six different standards and cooling rates of about 2 to 3 K per 5 to 10 sec.were employed. In some cases, in order to confirm and identify solid-state reactions, th() cooling curves were supplemented by heating runs.