Ostwald Ripening Behavior of Al8CeCu4 Phase in Al-14Cu-7Ce Alloy

The Ostwald ripening behavior of Al8CeCu4 phase in the Al-14Cu-7Ce alloy annealed at elevated temperatures was investigated using hardness testing, scanning electron microscopy, image analyses and physical modeling. Results indicate that the average radius of Al8CeCu4 particles increases while the hardness of the alloy decreases with increasing of annealing temperature and time. The ripening process of Al8CeCu4 phase is mainly controlled by the volume diffusion of Ce. The ripening kinetic of Al8CeCu4 particles satisfies well the modified Lifshits-Slyozov-Wagner theory, taking into account the effect of the volume fraction of Al8CeCu4 particles. The volume diffusion coefficient of Ce and the interfacial energy between the matrix and Al8CeCu4 phase were also calculated based on the general rate equation.