Structural Modification of Al65Cu16.5Ti18.5 Amorphous Powder through Annealing and Post Milling: Improving Thermal Stability

To improve thermal stability of the Al65Cu16.5Ti18.5 amorphous powder, structural modification of the amorphous powder was performed through annealing and post milling. Annealing above the crystallization temperature (Tx) not only induced nanoscale intermetallics to precipitate in the amorphous powder, but also increased Cu atomic percentage within the residual amorphous phase. Post milling induced the amorphization of the nanocrystal intermetallics and the formation of Cu9Al4 from the residual amorphous phase. Thus, a mixed structure consisting of amorphous phase and Cu9Al4 was obtained in the powder after annealing and post milling (the APMed powder). The phase constituent in the APMed powder did not change during the post annealing, which exhibited significantly improved thermal stability in comparison with the as-milled amorphous powder.