The crystallization process of amorphous Al80Fe20 alloy powders prepared by ball milling

The amorphous-to-crystalline transition during thermal annealing of amorpho us Al80Fe20 alloy powders prepared by ball milling was investigated by mean s of magnetothermal analysis and X-ray diffraction. Following structural re laxation and stress relief processes, a metastable phase precipitates durin g primary crystallization, and a mixture of intermetallic compound (theta-A l13Fe4) and fcc Al is developed further. On heating at constant rate anneal ing the first and succeeding reactions overlap to some extent in temperatur e. The apparent activation energy for primary crystallization amounts to 1. 99 +/- 0.10 eV by using the Kissinger method. In addition, the structure of the metastable phase, which has not been identified yet, is briefly discus sed. (C) 1999 Elsevier Science B.V. All rights reserved.