Spheroidizing Behavior of the Lamellar Al8CeCu4 Phase in Al-14Cu-7Ce Alloy

The spheroidizing behavior of the lamellar Al8CeCu4 phase in the Al-14Cu-7Ce alloy annealed at elevated temperatures was investigated by microstructure observation, hardness testing and theoretical calculation. Results show that with increasing the annealing temperature, the spheroidizing process of the Al8CeCu4 phase is accelerated. The controlling element for the spheroidizing process is determined to be Ce by theoretical calculation using the general rate equation. Microstructure observation indicates that the spheroidizing process of the Al8CeCu4 phase includes two successive steps, i.e., the curved lamella breaking into long rods by Gibbs-Thompson effect and then the rods separating into spherical particles further by Rayleigh's capillary induced perturbation mechanism.