Mechanically driven solid state amorphization reaction of ball-milled Nb50Zr10Al10Ni10Cu20 powders and the effect of annealing

Abstract A single amorphous phase of Nb50Zr10Al10Ni10Cu20 alloy powders was synthesized by ball milling the elemental powders at room temperature. During the first stage of milling, the atoms of Zr, Al, Ni and Cu migrated and diffused into the Nb (base material) lattice to form a bcc supersaturated solid solution that transformed into an amorphous phase with the same composition upon post-annealing at 725 K. As the milling time increased, the powders were subjected to continuous lattice imperfections that lead to gradual changes in the free energy, so that the solid solution phase is transformed to an amorphous phase. At the final stage of milling (720 ks) the crystallization temperature and the enthalpy change of crystallization for the obtained amorphous alloy were 963 K and −8.44 kJ mol−1, respectively.