Dispersoid Precipitation in Aluminum Alloys

Abstract

Dispersoid particles are critical to the control of recrystallization and grain growth behavior during thermomechanical processing of wrought aluminum alloys. The precipitation of dispersoids has some unique characteristics that must be considered to understand the microstructure and properties obtained in the final product. Dispersoids precipitate from a segregated cast structure and therefore are inhomogeneously distributed within a grain. They often precipitate from other phases that form during heating and then redissolve. Finally, their precipitation is often in competition with other microstructural processes, for example, a change in composition of the constituent phases. Understanding these factors is critical to control dispersoid precipitation. Furthermore, the increasing demand to replace primary aluminum with recycled material requires careful control of the dispersoid-forming elements, which tend to accumulate during recycling. Small changes in the amounts of these additions can have a large effect on recrystallization behavior and hence texture and properties.