Gibbs free energy difference in metallic glass forming liquids

Expressions of Gibbs free energy difference (ΔG) based on linear variation of heat capacity difference of liquid and solid ( Δ C p l - s ) with temperature in the super-cooled metallic liquid is reviewed. Attractively, hyperbolic variation of Δ C p l - s with temperature is suggested from the experimental data. According to this hyperbolic relationship, ΔG expression of Thompson and Spaepen could be also derived and a new ΔG expression is proposed. Calculations with the present expression have shown that ΔG values obtained from six glass forming alloys (La50Al30Ni20, Pd40Ni40P20, Zr52.5Cu17.9Ni14.6Al10Ti5, Zr41.2Ti13.8Cu12.5Ni10Be22.5, Cu47Ti34Zr11Ni8 and Mg65Cu25Y10) are consistent with experimental data. As compared with other ΔG expressions, deviations of the values calculated by the present expression from experimental data show the best stable at different reduced glass transition temperature (Trg = Tg/Tm) of amorphous alloys.