Evidence for effect of hydrostatic pressure during casting on glass-forming ability in Zr65Al7.5Ni10Cu17.5−xPdx (x = 0–17.5) alloys

We have observed evidence for hydrostatic argon-pressure-dependence of glass-forming ability (GFA) in Zr65Al7.5Ni10Cu17.5−xPdx (numbers indicate at.% x = 0–17.5) alloys. The alloys containing low amount of Pd (x = 0–5) and those with higher Pd (x = 7.5–17.5) showed an opposite tendency in term of the GFA-dependence on pressure. This is supposed to be due to the positive or negative volume changes from the supercooled liquid, to the corresponding primary crystalline/quasicrystalline phase. The result also indicates that the glass-forming ability, in this alloy system may still be improved by controlling the atmosphere condition during casting, despite the previous results (e.g. [A. Inoue, T. Zhang, J. Saida, M. Matsushita, M.W. Chen, T. Sakurai, Mater. Trans. 40 (1999) 1181]) reporting that the substitution of small amount of Cu with noble metals (Pd, Pt, Ag) in Zr–Al–Ni–Cu-based alloys tends to facilitate the nucleation of crystalline or quasicrystalline phase within the glassy one.