Glass Forming Ability of Zr-Based Amorphous Alloys

The glass forming ability (GFA) of five Zr-based alloys, namely Zr(625)A(12.1)Cu(7.95)Ni(17.45), Zr63Al11.4,Cu9.3Ni16.3, Zr63.5Al10.7Cu10.7Ni15.1, Zr64Al8.7Cu14.4Ni14.2, and Zr65Al8.7Cu14.4Ni11.9, is studied based on the thermodynamic parameter i.e., the Gibbs free energy difference (Delta G(T-g)) between the super-cooled liquid and the corresponding crystalline phase. Two different equations of Delta G, given by Lad et al., are used and the calculated values of Delta G(T-g) are plotted against the critical dimension (Z(max)) to understand the relationship between the GFA and Delta G(T-g). It is found that Delta G(T-g) obtained by Lad-1 expression, shows a strong correlation with Z(max) (R-2 = 0.955). Other GFA parameters (gamma(m), alpha, delta, xi, omega, omega(2), omega',beta, beta', etc.) are also calculated to understand the glass forming ability and thermal stability of metallic glasses. Among all five compositions, Zr62.5Al12.1,Cu7.95Ni17.45 is found to have the best glass forming ability with Delta G(T-g) values to be 5.166 and 4.359 kJmol(-1) respectively by Lad-1 and Lad-2 expression.