Dynamic heterogeneities in the glassy and undercooled states of the amorphous system Zr65Al Cu35−

Abstract Anelastic behaviour of the metallic glass former Zr 65 Al x Cu 35− x can be described in terms of a Kohlrausch–Williams–Watts function which is characterized by the stretching exponent β . The temperature dependence of β with respect to Al-content in the alloy can be consistently explained with the assumption of the existence of dynamical heterogeneities. This assumes collectively moving atoms in clusters as a specific dynamic element of the system. Typical cluster-sizes of about 2–3 nm diameter are estimated in the vicinity of the glass transition temperature T g . This leads to an improved understanding of atomic processes and dynamics in glass forming materials.