Gibbs free energy and activation energy of ZrTiAlNiCuSn bulk glass forming alloys

The Gibbs free energy difference between the supercooled liquid and the crystalline mixture for the (Zr_52.5Ti₅Al₁₀ Ni_14.6Cu_17.9)_{(100- x)/100}Sn_x (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 difference decreases first because of the increase 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 energies of Zr_52.5Ti₅Al₁₀ Ni_14.6Cu_17.9 and (Zr_52.5Ti₅Al₁₀ Ni_14.6Cu_17.9)_0.97Sn₃ were evaluated by the 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 the appropriate addition of Sn.