Effect of the repeated melting of mother ingot on the stability of icosahedral phase precipitated from Zr-Al-Ni-Cu-Ag glass

Since the icosahedral phase (I-phase) was first found in a rapidly solidified Al84Mn16 alloy by Shechtman et al.1] in 1984, a lot of studies on I-phase have been carried out. The typical systems in which the icosahedral quasicrystals can be formed include Al-2,3], Pd-4] and Ti-based5] ones. In most cases, the I-phase forms as metastable phase and its formation depends on the cooling rate. Later, precipitation of I-phase during the crystallization of Zr-based metallic glass was reported…

Effect of the repeated melting of mother ingot on the stability of icosahedral phase precipitated from Zr?Al?Ni?Cu?Ag glass

Differential scanning calorimetry (DSC) shows that repeated melting of mother ingot improves the stability of icosahedral phase (I-phase) precipitated from Zr65Al7.5Ni10Cu12.5Ag5 glass. The Kissinger analysis of crystallization implies that the effective activation energies for the pre-cipitation of I-phase and its decomposition considerably increases due to the repeated melting of mother ingot. Repeated melting of mother ingot refines ingot microstructure. Because of structure heredity, the size of the short-range orders (SROs) in the glassy alloy produced from the mother ingot with finer microstructure becomes smaller, which makes the rearrangement of atoms more difficult, and the I-phase more stable.