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 102.5 K s-1, the peak value of nucleation rate of Zr66Al8Ni9Cu16 decreases to 105 mol-1 s-1. To Zr66Al8Cu7Ni19, Zr66Al8Cu12Ni14, Zr66Al9Cu16Ni9 and Zr66Al7.5Cu17.5Ni10 alloys, with increasing content of Cu, the supercooled liquid region ΔTx rises and the nucleation rate falls gradually. [ABSTRACT FROM AUTHOR]