Sputter-deposited fe-al alloys were studied with transmission electron microscopy (tem), auger electron spectroscopy, and selected area electron diffraction (sad). The alloys were deposited with thicknesses of approximately 50 nm onto carbon-coated tem grids. All samples were deposited by planar magnetron sputtering onto substrates held at liquid nitrogen temperature. The compositions studied were fe70al30, fe50al50, fe30al70, fe10al90 and fe5al95. The fe70al30 composition was polycrystalline body-centered cubic (bcc) with a lattice constant of 0.291 nm, and the fe5al95 composition was polycrystalline face-centered cubic (fcc) with a lattice constant of 0.41 nm. The fe50al50 composition contained approximately 2 vol % bcc crystallites in an amorphous matrix. Both the fe30al70 and fe10al90 samples were amorphous to tem and sad. The amorphous alloys and the amorphous regions of the fe50al50 alloys display an "island-channel" structure that is detectable with tem. The data indicate the presence of only three phases in this metastable system: polycrystalline bcc, amorphous, and polycrystalline fcc.
J. Non-cryst. Solids, V. 81, 1986, PP. 155-161