In-Situ Electron Diffraction Study of Structural Change in the Super-Cooled Liquid Region in Amorphous La-Al-Ni Alloy

<jats:title>Abstract</jats:title><jats:p>Atomic structures of an amorphous La<jats:sub>55</jats:sub>A1<jats:sub>25</jats:sub>Ni<jats:sub>20</jats:sub> alloy in the supercooled liquid state have been investigated by <jats:italic>in-situ</jats:italic> electron diffraction using a specimen-heating stage in TEM and the imaging-plate intensity recording. From the analysis of atomic pair distribution functions, changes in interatomic distances and coordination numbers were clearly observed at temperatures in the supercooled liquid state. From the reverse Monte Carlo simulations, structural units (icosahedral, Archimedean anti-prism and trigonal prism atomic clusters) typical of the metallic glass structure were found and increased in the supercooled liquid region. In addition, the deformation behavior was investigated using tensile test. The superplastic elongation was confirmed at optimum strain rates in the supercooled liquid region. From the TEM observation of tensile tested specimens with superplastic elongation, β-La (fcc) nano precipitates in the amorphous matrix were confirmed. The superplasticity in this alloy is thought to originate in viscous flow due to the glassy structure formation but is closely related to an additional flow mode with the microcrystalline precipitation from the amorphous state during the deformation.</jats:p>