Abstract: The Gibbs free energy differences between the supercooled liquid and the crystalline mixture for the (Zr52.5Ti5Al10-Ni14.6Cu17.9) (100-x)/100Snx (x=0, 1, 2, 3, 4 and 5) glass forming alloys are estimated by introducing the equation proposed by Thompson, Spaepen and Turnbull. It can be seen that the Gibbs free energy differences decrease first as the increases of Sn addition smaller than 3, then followed by a decrease due to the successive addition of Sn larger than 3, indicating that the thermal stabilities of these glass forming alloys increase first and then followed by a decrease owing to the excessive addition of Sn. Furthermore, the activation energy of Zr52.5Ti5Al10-Ni14.6Cu17.9 and (Zr52.5Ti5Al10-Ni14.6Cu17.9)0.97Sn3 was evaluated by Kissinger equation. It is noted that the Sn addition increases the activation energies for glass transition and crystallization, implying that the higher thermal stability can be obtained by appropriate addition of Sn.

Key words: Bulk glass forming alloy, Supercooled liquid, Gibbs free energy...