Thermodynamics of Cu_(47)Ti_(34)Zr_(11)Ni_(8), Zr_(52.5)Cu_(17.9)Ni_(14.6)Al_(10)Ti_(5) and Zr_(57)Cu_(15.4)Ni_(12.6)Al_(10)Nb_(5) bulk metallic glass forming alloys

摘要

The differences in the thermodynamic functions between the liquid and the crystalline states of three bulk metallic glass forming alloys, Cu_(47)Ti_(34)Zr_(11)Ni_(8), Zr_(52.5)Cu_(17.9)Ni_(14.6)Al_(10)Ti_(5), and Zr_(57)Cu_(15.4)Ni_(12.6)Al_(10)Nb_(5), were caloulated. The heat capacity was measured in the crystalline solid, the amorphous solid, the supercooled liquid, and the equilibrium liquid. Using these heat capacity data and the heats of fusion of the alloys, the differences in the thermodynamic functions between the liquid and the crystalline states were determined. The Gibbs free energy difference between the liquid and the crystalline states gives a qualitative measure of the glass forming ability of these alloys. Using the derived entropy difference, the Kauzmann temperatures for these alloys were determined.