Previously published calorimetric study of amorphous Ta-50 at.%Al alloy powders is complemented by structure and morphological studies. The alloy powders were prepared by mechanical alloying (MA) from pure elemental powders of Ta and Al. The alloy powders have been characterized by optical microscopy, scanning electron microscopy and transmission electron microscopy. The results have shown the MA process takes place through three stages, that is to say, agglomeration, amorphization and homogenization stages.