A structural and calorimetric study of the transformations in sputtered Al–Mn and Al–Mn–Si films

Abstract

Scanning and isothermal calorimetry, together with x-ray diffraction and high resolution transmission electron microscopy (TEM), have been used to characterize Al–Mn and Al–Mn–Si films sputtered onto substrates at 60 °C, 45 °C, and −100 °C. In the case of Al0.83Mn0.17, the monotonically decreasing isothermal calorimetric signal, characteristic of a grain growth process, has proved decisive in identifying the as-sputtered “amorphous” state as microquasicrystalline, with an average grain size of ∼ 20 Å, in agreement with an estimate of correlation range from the x-ray pattern. The TEM at 400 keV reveals well-defined atomic or lattice images in annealed films but only barely resolved grains (ordered clusters) in the as-sputtered films. The relation between the metallic glass and the microquasicrystalline state in these alloys is discussed.