Solidification and phase relations in Nb-based Nb-Al-Fe alloys

Nb-based intermetallic alloys consisting of Nb solid solution and high-melting, strengthening intermetallic phases are of considerable interest for structural applications at very high temperatures.

In a project with the company ATI Specialty Alloys and Components, the high-temperature phase equilibria and solidification behavior of Nb-based ternary alloys with Al and Fe were established yielding the liquidus surface in the Nb corner of the ternary system and isothermal sections at 1450 and 1600 °C [1]. In addition, the phase relations in the complete ternary Al-Fe-Nb were calculated by thermodynamic modelling using the Calphad approach within a cooperation with Nanning university [2], and a comprehensive assessment of the complete system was performed [3].