Abstract
Microstructure and grain growth characteristics of pre-deformed Al–Bi alloys annealed at 773 K were investigated mainly by scanning electron microscopic (SEM) observation. In addition to very fine liquid-Bi particles in the grains, large Bi particles were observed on the grain boundaries, and non-precipitation zones are mainly formed in the vicinity outside of the curved grain boundaries. This result suggests that the Bi particles on the grain boundaries were dragged by the grain boundaries. The grain growth is significantly retarded by the effect of this dragging, the origin of which can be explained by the decrease of the interfacial energy of the intragranular Bi particles. Quantitative analysis showed that the diffusion of Al atoms in the liquid Bi particles on the grain boundaries is the rate-determining process of this dragging.
