Formation of ultrafine nanostructure by crystallization of Zr52Al6Cu14Ni8Fe20 metallic glass

The short-range order and the crystallization behavior of amorphous Zr52Al6 Cu14Ni8Fe20 alloys have been investigated by means of calorimetry and x-ray diffraction. The amorphous structure transforms upon annealing without for mation of long-range order. An ultrafine microstructure consisting of about 60 vol % cubic NiZr2 crystal-like clusters with a size of [D]approximate t o 2 nm embedded in a residual amorphous matrix phase forms as a first step of crystallization resulting from high nucleation rate combined with low gr owth velocity. In a second step growth of the clusters to crystals up to a mean diameter of [D]approximate to 4-5 nm takes place as a distinct process . (C) 2000 American Institute of Physics. [S0003-6951(00)04934-2].