An Investigation of Sputtered Al-Cu-Fe-Cr Quasicrystalline Films Via Synchrotron Diffraction

Abstract

AbstractAnalysis of the phase relationships of Al-Cu-Fe-Cr based sputtered films, before and after various annealing treatments, was carried out via grazing incidence x-ray scattering (GIXS) at SSRL on beamline 7-2. The “as-deposited” films were composed primarily of nanoscale grains whose structure were mainly quasicrystalline (QC) and its approximants, plus a nano-crystalline phase was also observed in one sample. None of these precursor films exhibited any degree of amorphous character. GIXS studies, in the symmetric and asymmetric modes, revealed that grain growth due to the post-deposition heat treatments caused a decagonal QC phase to evolve and dominate the crystalline phases, which composed the film. These ≍10 µm thick films were created by sputter deposition with a DC magnetron source via an Al-Cu-Fe-Cr powder pressed target, giving a nominal sample composition of Al75Cu4Fe8Cr10O3. Two types of annealing treatments were performed using an Argon atmosphere. Anneal of a precursor film for 4 hours at 500°C showed a large fraction of decagonal and approximant phases, while anneal of a precursor film for 2 hours at 400°C and 2 hours at 550°C showed a large fraction of the crystalline phase.