The effect of milling conditions and impurities on the properties of mechanically alloyed Zr-based metallic glasses with wide supercooled liquid region

Zr-Al-Cu-Ni and Zr-Ti-Cu-Ni amorphous alloys exhibiting a significant supercooled liquid region have been prepared by mechanical alloying of elemental powders. The alloying process upon milling and the resulting glassy alloys were characterized by x-ray diffraction and differential scanning calorimetry (DSC). The homogeneity of the as-milled powders as well as their thermal stability depend strongly on the impurity levels of the starting materials and the contamination introduced during milling. Iron and oxygen contamination can significantly affect the thermal stability of the powders. This will be discussed in detail for various Zr-Al- and Zr-Ti-based samples, showing especially Zr-Al-based metallic glasses are very sensitive to impurity effects. The data are compared with results for melt quenched samples.