Mechanically alloyed Al-Li powders

Mechanically alloyed powders with the composition Al_0.7Li_0.3 are synthesized. Materials milled for different times are studied using electron microscopy, X-ray diffraction, and thermal analysis. A solid solution of Li in Al (α-phase) is formed with as much as 10 at.% of dissolved Li. The LiAl intermetallic δ-phase is readily produced by mechanical alloying but disappears after extended milling times. The final product of milling for 102 h consists of an X-ray amorphous phase. Mechanically alloyed powders heated in inert environment exhibit several weak exothermic reactions between 420 and 700 K, and two endothermic reactions, around 810 and 870 K. All the observed relaxation processes become less pronounced and eventually become undetectable as the milling time increases and an amorphous material is produced.