Influence of decomposition on the thermal stability of undercooled Zr-Ti-Cu-Ni-Al alloys

The critical temperature for decomposition significantly influences the crystallization behavior in the undercooled liquid regime of a metallic glass. In alloys with a critical temperature higher than the glass transition temperature, decomposition triggers crystallization. In this case, nanocrystallization and an additional exothermic peak in differential scanning calorimetry are observed. The glass forming ability of a metallic alloy is determined by the nucleation of a primary phase close to the liquidus temperature of the alloy, far above the critical temperature for decomposition. Therefore, the thermal stability of a glass is not directly related to the glass forming ability, as measured by a critical cooling rate for amorphization.