Mossbauer studies of phase stability in mechanically stressed Fe-28 at% Alalloy

Mechanical stress is introduced in Fe-28 at% Al alloy by filing a cast and homogenised ingot to fine powder. Long-range order is destroyed to a great extent as a result of this stress. Mossbauer and XRD studies show that heat ing the stressed alloy at 400 degrees C is favourable to its reordering to DO3 structure, while heat treatment in the range 480-540 degrees C leads to the formation of alpha-Fe along with the other ordered phases. It is sugge sted that a fraction of iron ions is migrated from the A-sublattice to the B-sublattice due to vacancy creation and rearrangement during filing, and i t remains there even after prolonged heating. (C) 2000 Elsevier Science B.V . All rights reserved.