SUPERSATURATED SOLID-SOLUTIONS AND METASTABLE PHASES FORMATION THROUGH DIFFERENT STAGES OF MECHANICAL ALLOYING OF FETI

Elemental equiatomic Fe-Ti powder mixture was mechanically alloyed in high energy ball mill. XRD, DTA and Mossbauer spectroscopy (at liquid nitrogen temperature) were utilized to monitor the kinetics as well as the accompanied structural and phase transformations through differen t stages of milling. Our experiments showed that formation of nanocrys talline FeTi compound proceeds via the formation of the supersaturated solid solutions beta-Ti(Fe) anal alpha-Fe(Ti) at the interface. After 36 hours of milling, the main part of powder mixture transformed not only to FeTi but also to Fe2Ti intermetallic compound. The transition of last part of supersaturated solid solutions beta-Ti(Fe) to those in termetallic phases was observed after annealing of this sample at 600 degrees C. (C)1998 Acta Metallurgica Inc.