Thermal Stability of Nanograin Structure in Cu-Zn Alloy System

摘要

To describe the thermal stability of the nanocrystalline solid solution with weak segregation such as Cu-Zn system, we developed a hybrid model combining the first principles calculation and thermodynamic evaluation. The dependence of the solute segregation behavior on the solute concentration, grain size and temperature were demonstrated. We found that the segregation energy does not change with the solute concentration monotonically. At a constant solute concentration and a given temperature, a nanograin structure can remain stable if the initial grain size is kept in a critical range. The model predictions were confirmed by the experimental measurements that a state of steady nanograin growth can be achieved by designing a certain solute concentration and a proper initial grain size.