MOSSBAUER SPECTROSCOPIC STUDY OF HEAT-TREATED AND CONTROL-COOLED FE3AL ALLOYS

The Fe-Al system forms a model object of transition metal-sp element s ystem. FE-Al alloys containing 21-31 at % Al are known to exhibit seve ral attractive physical properties which render them candidate materia ls for structural and magnetic applications. These magnetic and physic al properties can be varied by altering the composition and the proces sing routes. Keeping this in mind, Mossbauer spectra of five Fe-24 at % Al and Fe-25 at % Al alloy samples processed via different routes ha ve been studied. The analysis of the Mossbauer parameters, distributio n of hyperfine magnetic fields, P(H) and H-values were used to identif y various Fe-atom configurations (nearest neighbour or next nearest ne ighbour) associated with the phases formed by different processing rou tes. The results obtained from the present study indicate that the ave rage hyperfine field [H] depends on the average rate of cooling follow ed during the precipitation of these phases.