Effect of Homogenizing Heat Treatment of Liquid Aluminum–Copper Alloys on the Structure of Rapidly Crystallized Specimens

Centrifugal casting into a massive slot chill mold was used to prepare two series of specimens of alloys of the Al – Cu system, containing from 10 to 32.2 at.% Cu. The first series was fabricated without a homogenizing heat treatment of the melt, while the second series was fabricated with heating of the melt to 1400°C. Both kinds of specimens were cast at the same temperature in order to provide for the same cooling rate of about 104 K/sec. The structures, phase compositions and microhardnesses of the structural components are compared. It is established that the homogenizing heat treatment changes the kinetics of crystallization and, hence, the proportion of phases in the alloy structure and the copper content in them.