Study of microsegregation in Al-Cu alloys using impulse atomization as an RSP

Rapid Solidification Processes (RSP) are known to produce novel microstructures with improved mechanical properties. These microstructures can show solid solubility extension, solute trapping or partitionless solidification etc. and have been explained in terms of microsegregation during the rapid solidification process. This paper addresses the microsegregation in Al-Cu (4.5, 10, 17, 24 wt %) alloys produced by Impulse Atomization (IA). Rapid solidification of the above mentioned alloys were carried out using impulse atomization and the droplets produced were analyzed for microsegregation using SEM techniques. A heat transfer model incorporating the LGK model, for s-l interface growth, has also been developed for solidification/microsegregation of these atomized droplets. Some preliminary experimental results are discussed and compared with this model along with Equilibrium and Scheil models. (author)