Simulation of the casting and homogenization of two 6xxx series alloys

The homogenization of two 6xxx alloys, 6061 and 6069 has been investigated. The distribution of the alloying elements after casting has been studied using electron microprobe measurements and compared to the results of a multicomponent Scheil simulation. After casting, some of the specimens were heavily deformed using equal channel angular extrusion (ECAE). The homogenization kinetics of both deformed and non-deformed material have been measured by monitoring conductivity change as a function of homogenization time. A simple model for the particle dissolution and solute redistribution during homogenization has been developed, which is initialized with data from the Scheil simulation. The predictions of the model agree well with the experimental measurements. It is shown that ECAE prior to homogenization leads to a refinement in grain size and dispersoid size, but does not appear to greatly accelerate the homogenization kinetics.