Superplastic behavior of a Zr–10Al–5Ti-–17.9Cu–14.6Ni metallic glass in the supercooled liquid region

Abstract

The mechanical behavior of metallic glasses is characterized by either inhomogeneous or homogeneous deformation. Inhomogeneous deformation usually occurs when a metallic glass is deformed at room temperature (i.e., low temperature) and is characterized by the formation of localized shear bands, followed by the rapid propagation of these bands, and sudden fracture. Consequently, when a metallic glass is deformed under tension it exhibits only limited macroscopic plasticity ( 0.70T{sub g}), and the material can often exhibit significant plasticity, especially in the supercooled liquid (SL) region. In summary, large tensile ductility can generally be obtained in the supercooled liquid region from a metallic glass with a large {Delta}T. The exact deformation mechanism, however, and in particular whether an alloy deforms by Newtonian viscous flow remains a controversial issue. The purpose of this paper is to report an example of non-Newtonian behavior in a cast amorphous Zr-10Al-5Ti-17.9Cu-14.6Ni alloy in the supercooled liquid region.