Phases in the crystallization process of Zr65Al7.5Ni10Cu17.5 metallic glass

The crystallization process of metallic glass Zr65Al7.5Ni10Cu17.5 (atom fraction in %) were studied by transmission electron microscopy and X-ray diffraction. Two stages of crystallization process, which are indicated by the two exothermic peaks in the differential scanning calorimetry diagram, were studied separately. It is found that the phases in the various stage of the crystallization are different. In the first stage, it consists mainly of tI-CuZr2 and tP-Al2Zr3 phases, between which a definite orientation relationship is found. While in the second stage, in addition to the above phases, phase hP(2)-Al2NiZr6 and phase hP(3)-alpha-Zr appear, between which another orientation relationship is also found. At the same time, a comparison is made based on the study of the phases exist in the arc-melted master ingot. The lattice parameters of the identified phases were determined and some interesting similarities were found. According to these similarities, all the phases were classified into two groups. The first is: oB, tI-CuZr2, and hP(3)-alpha-Zr; the other is: hP(2), tP-Al2Zr3 and hP(1)-Al2NiZr6. The relationships between phases in these two groups were investigated and the probable reasons that may result in these relationships were discussed.