Prediction of glass forming ability in Cu-Zr-Ti ternary amorphous alloys

By using CALPHAD technique, the driving forces for crystallization from the undercooled liquid in Cu-Zr-Ti ternary alloys were evaluated by means of Turnbull and Thompson-Spaepen (TS) Gibbs free energy approximate equations, respectively. Time- temperature-transformation (TTT) curves and the corresponding critical cooling rates of thirteen compositions of Cu-Zr-Ti system were calculated with Davies-Uhlmann kinetic equations based on continuous nucleation theory. With Turnbull and TS equations, the calculated critical cooling rates for these Cu-Zr-Ti alloys are in the range of 1.38 × 102-7.34 × 105 K/s and 0.64-1.36 × 104 K/s, respectively. It is shown that both groups of the calculated values for the glass forming ability(GFA) are in agreement with the experimental data qualitatively. The glass forming ability (GFA) with TS equation is more in accordance with the experimental results than that with Turnbull equation. This work suggests that combination of CALPHAD technique and kinetic calculation may provide a valid method for the prediction of GFA in Cu-Zr-Ti alloys.