Formation of amorphous Ni-Zr alloys by mechanical alloying of mixtures of the intermetallic compounds Ni11Zr9 and NiZr2

Abstract

Amorphous Ni40Zr60 and Ni50Zr50 alloy powders were synthesized by mechanical alloying of mixtures of the intermetallic compounds Ni11Zr9 and NiZr2. Milling these compounds together in the proper proportions resulted in material transfer and amorphization of alloys with compositions Ni40Zr60 and Ni50Zr50. After crystallization in a differential scanning calorimeter, the same products of crystallization were observed as for crystallization of liquid quenched amorphous alloys of the same compositions. The driving force for the amorphization of Ni11Zr9+NiZr2 mixtures is believed to be either the steep rise in free energy of the line compounds as material transfer moves their compositions off stoichiometry, or the creation of a critical defect concentration in the intermetallic compounds.