Thermally enhanced and mechanically driven glass-formation reactions of multilayered Cu33Zr67 powders

A single phase of glassy Cu33Zr67 powders has been synthesized by postannealing the mechanically alloyed Cu33Zr67 multilayered composite powders at 685 K for 1.8 ks. The heat formation of the obtained glassy phase has been measured directly and found to be -2.59 kJ/mol. The glassy powders transform to a big-cube CuZr2 metastable phase (E9 structure) upon heating to 731 K. This metastable phase does not withstand the temperature increase during the differential scanning calorimetry (DSC) analysis and, therefore, transforms completely into the most stable phase of tetragonal CuZr2 (C16 structure) at 993 K. In contrast to the annealing process of the multilayered particles, the glassy phase that was obtained by milling the starting materials for a longer ball-milling time is crystallized into the tetragonal phase of CuZr2 through a single step.