Structural origin of the high glass-forming ability in Gd doped bulk metallic glasses

The structural origin of the high glass-forming ability (GFA) in Gd-doped CuZrAl bulk metallic glasses was investigated via synchrotron radiation techniques combined with simulations. It is found that 2 at. % Gd addition increases and stabilizes the solute-centered clusters, which leads to the relatively high atomic- and cluster-level packing efficiency and GFA in Cu(46)Zr(45)Al(7)Gd(2) alloy. However, the presence of Al-Gd solute-solute bonding in Cu(46)Zr(42)Al(7)Gd(5) decreases the packing efficiency, deteriorating the GFA of this alloy. These findings may extend our understanding on the sensitive dependence of GFA on the concentration of doping atoms in a number of multicomponent bulk metallic glasses. (C) 2010 American Institute of Physics. [doi:10.1063/1.3485117]