Redistribution behavior of constitutional elements at an initial crystallization stage in the Zr65Al7.5Ni10Cu17.5 glassy alloy

Abstract

We investigated the transformation behavior from glassy to Zr2Ni phase in the Zr65Al7.5Ni10Cu17.5 glassy alloy with a low oxygen content below 400 ppm mass%. The mostly single face centered cubic Zr2Ni phase precipitated as a primary phase at the initial crystallization stage. The Zr2Ni particles had a cubical morphology in the diameter range of 300 to 500 nm and were in an isolated state for the sample annealed at the temperature near crystallization temperature. A significant redistribution leading to the enrichment of Zr and Ni into the Zr2Ni phase is confirmed. Moreover, it is recognized that Cu and Al are rejected from the Zr2Ni phase. The compositional differences of Zr, Al, Ni, and Cu between the Zr2Ni and remaining glassy phases are in the range of 1.5 to 5 at.%. It is strongly suggested that such a significant redistribution of the constitutional elements restrains the nucleation and growth of crystalline phases. It is one of the important factors for the stabilization of the glassy state in Zr–Al–Ni–Cu alloy.