Phase Equilibria in the Fe-Al-Nb(-B) System at 700 °C

Abstract

Within a composition range that is of interest for future alloy developments and at a possible application temperature of 700 °C, phase equilibria between Fe3Al and the Nb(Fe,Al)2 Laves phase have been determined. It was found that the solid solubility for Nb in Fe-Al increases by five times, when the Al content increases from about 25 to 35 at.% Al. Besides, the compositions of the co-existing phases, their lattice constants, Curie temperatures, transition temperatures and the solidus and liquidus temperatures of the Fe-Al-Nb alloys, some additionally doped with boron, have been determined.