Comparative study on glassy phase stabilities of Zr-Co-Al and Zr-Ni-Al metallic glasses

The phase stabilities of Zr-Co-Al and Zr-Ni-Al metallic glasses have been investigated by the thermal analysis and compared with each other. It is found that the largest ΔT_x, T_g/T_l and γ parameters of the former are larger than those of the latter, indicating that the former have higher glassy phase stability than the latter. It is also found that the optimum compositions of the former are Zr-poorer and Al-richer than those of the latter and that their transition metal compositions are almost the same. Since Co and Ni have almost the same atomic radius and mixing enthalpy against Zr which are factors correlated with the glassy phase stability, this composition difference may be attributable to another factor, i.e. their difference of the electronic contribution due to the different electronic structure around the Fermi level.