GLASS-FORMATION IN A MULTICOMPONENT ZR-BASED ALLOY BY MECHANICAL ATTRITION AND LIQUID UNDERCOOLING

The synthesis of a multicomponent Zr60Al10Ni9Cu18Co3 glass by mechanic al alloying has been investigated using thermal and structural analysi s and compared with a metallic glass produced by liquid undercooling. The solid-state amorphization reaction is preceded by rapid solution o f smaller solute atoms in the Zr matrix with a concomitant reduction i n grain size to 10 nm at the amorphization onset. A fully amorphous me chanically alloyed sample shows relaxation compared to a sample synthe sized by liquid cooling probably due to removal of residual inhomogene ities on the scale of the nanocrystal size at amorphization. While the kinetic pathways for the two synthesis methods differ, the relaxed am orphous phases from each method exhibit identical thermodynamic proper ties. (C) 1997 American Institute of Physics.