The excess wing of bulk metallic glass forming liquids

We performed the dynamic mechanical relaxation measurements in typical metallic Zr(46.75)Ti(8.25)CU(7.5)Ni(10)Be(27.5) and Ce(70)Al(10)Cu(20) supercooled liquids close to their glass transition temperature T(g). An obvious excess wing is observed both in temperature- and frequency-dependent loss modulus curves by the calculation of the relaxation time of cc-relaxation in supercooled liquids using the Kohlrausch-Williams-Watts equation in combination with the Vogel-Fulcher-Tamman equation. The results support that the slow beta-relaxation process exists in the metallic liquids and the excess wing is the high-frequency flank of the beta-relaxation. The existence of beta-relaxation in the metallic supercooled liquids affirms that the beta-relaxation process arises from the small-scale translational motions of atoms which are hindered in its metastable atomic solid-like islands. (c) 2006 Elsevier B.V. All rights reserved.