Formation of non equilibrium solid phases in Fe-Nb multilayered films by ion irradiation

In the Fe-Nb system, amorphous alloy, metastable crystalline fee and hexago nal phases were formed in Nb-rich multilayered films by room temperature 20 0 keV xenon ion mixing. A heat of formation diagram of the system was const ructed based on Miedema's model and Alonso's calculation method, and the di agram gave a relevant interpretation for the observed phase formation. The formation of fee metastable phase can be interpreted by a reverse martensit ic transition of bcc-fcc. The amorphous and hexagonal phases are thought to form through a traditional nucleation and growth mechanism with an additio nal consideration of the irradiation effect, which kinetically hindered the formation of a complicated intermediate compound.