Grain and phase growth in the two-phase Al-Cu alloys containing 6, 11, 1 7, 24 and 33 wt % Cu were investigated by annealing at 535 °C for 0.5-100 h. The grain and phase sizes of the κ phase are seen to be larger than that of the θ phase. The size of κ phase decreases whereas the size of θ phase increases with increasing copper content in the alloy. As such, the κ phase- and grain-size distributions are broader than the θ phase- and grain-size distributions, but the size range depends on annealing time and alloy composition. The grain sizes of the κ, dκ, and θ, dθ, phases can be related to the volume fraction of the θ phase, fθ, according to the equation dκ = 0.497 dθ/fθ. © 1994 Chapman & Hall.