Atomic structure of Al89La6Ni5 metallic glass

Atomic structures of amorphous Al89La6Ni5, prepared by single-roller melt spinning, and pre-annealed at 493 and 588 K for 1 h, were characterized by differential scanning calorimetry, x-ray diffraction with a large wavevector transfer value, La L3-edge and Ni K-edge x-ray absorption fine structure and the reverse Monte Carlo technique. In the as-prepared amorphous alloy, our study reveals that the Ni-Al distance is 2.38 ± 0.02 A coupled with a coordination number as low as 6.2. The Al-Al distance was found to be ∼4.5% shorter than the nominal atomic diameter of aluminium and the coordination number to be ∼39% less than expected from the dense random packing model. Crystallization of the Al89La6Ni5 glassy alloy at high temperatures can be described as follows: [amorphous alloy] → [fcc-Al] + [bcc-(AlLa)] + residual amorphous →[fcc-Al] + [o-Al3Ni ] + [o-La3Al11 ]