On the synthesis of Zr-based bulk amorphous alloys from glass-forming compounds and elemental powders

Abstract

The possibility of producing Zr-based bulk amorphous alloys (Zr65Cu17.5Ni10Al7.5 and Zr57Ti5Cu20Ni8Al10) by mechanical alloying (MA) from either a mixture of elemental powders (EP), or a mixture of glass-forming compounds (GFC), has been investigated. A preliminary study of the crystal structure stability of the GFC-ingredients during mechanical milling was performed. Amorphization was found to be significantly enhanced during MA by using a GFC mixture. A considerable difference in the phase transformations observed on heating the amorphous phase (AP) was noted for alloys obtained from GFC, as compared with those produced by melt quenching (MQ) or milling of a mixture of elemental powders. It is shown that the amorphous phase obtained by MA from GFC has a wider undercooled liquid region between the glass transition temperature Tg and the crystallization temperature Tx than the amorphous phase produced by the conventional MQ technique.