Calculation of transient nucleation rate for Pd and Zr based metallic glass alloys

In order to investigate the glass forming ability, a new method to evaluate the transient nucleation rate of glass alloys is provided in the present paper using the parameters of bulk metallic glasses, such as onset melting temperature, glass transition temperature, viscosity and the cooling rate. The transient nucleation rates of Au₈₁Si₁₉, Pd₇₅Si₂₅ and Zr–Al–Ni–Cu alloys are obtained with this method. The computing result for Au₈₁Si₁₉ agrees well with that of the literature. The results show that with increasing viscosity or cooling rate, the nucleation rate drops sharply. When the cooling rate reaches to 10³ K s^–1, the peak value of nucleation rate of Pd₇₅Si₂₅ falls to 10⁴ mol^–1 s^–1. Under the cooling rate of 10^2·5 K s^–1, the peak value of nucleation rate of Zr₆₆Al₉Ni₉Cu₁₆ decreases to 10⁵ mol^–1 s^–1. To Zr₆₆Al₈Cu₇Ni₁₉, Zr₆₆Al₈Cu₁₂Ni₁₄, Zr₆₆Al₉Cu₁₆Ni₉ and Zr₆₅Al_7·5Cu_17·5Ni₁₀ alloys, with increasing content of Cu, the supercooled liquid region ΔT_x rises and the nucleation rate falls gradually.