Metastable phases in vapour‐quenched Al₇₈Cu₂₂ film

Abstract

Abstract. The structure and structural changes of an A178C~22 (atolo) alloy film produced by coevaporation onto a cooled substrate have been investigated with transmission electron microscopy. A series of metastable phase transitions were observed during the crystallization from the as-deposited amorphous phase to the final equilibrium state. The deposit structure at room temperature consists of a mixture of fine grained a' crystallites (fcc, f = 4.81 A ) with an amorphous phase, and some welldefined crystals with an fcc lattice (a = 7.18 A, namely all. The subsequent annealing led to the grown crystals transforming to an ordered a' phase. It is argued that the development of such a transition is the result of a gradual atomic rearrangement -first topologically then a chemically predominant disorder-order transition.