Mechanically induced devitrifications of ball-milled Zr70Pd20Ni10 glassy alloy powders

Abstract

Mechanical alloying using a high-energy ball milling technique was used to fabricate a single glassy phase of Zr70Pd20Ni10 alloy powders after 100 h milling time. Annealing the glassy powders at a temperature just below the crystallization onset temperature led to thermally enhanced devitrification and the formation of a metastable big-cube phase with a lattice constant of 1.2289 nm. The same metastable phase was obtained upon subjecting the end product of the glassy powders to further ball milling time (150 h). This metastable big-cube phase could no longer withstand the shear and impact stresses generated by the milling media and transformed into a new metastable phase of face-centered cubic Zr70Pd20Ni10. The lattice constant of this metastable phase was calculated to be 0.56838 nm. These metastable phases are new and have never been, so far as we know, reported for the ternary Zr–Pd–Ni system or its binary phase relations.