Analysis of in-flight oxidation during reactive spray atomization and deposition processing of aluminum

This work defines a model to predict the characteristics of materials proce ssed using reactive spray atomization and deposition. The materials conside red are aluminum alloys while target dispersoids are primarily oxides. Thes e may be obtained by the reaction of oxygen-containing atomization gas mixt ures with molten alloy droplets. Droplet position and velocity histories ar e obtained from the numerical solution of the one-dimensional equation of m otion. The energy equation inside the droplet is solved numerically using f inite differences to predict the spatially resolved temperature field. The solid/liquid interface progression rate is estimated using a power law whil e an oxidation rate expression based on the Mott-Cabrera theory is used for the oxide thickness. Such a model should prove very valuable in determinin g the parameters controlling the volume fraction and the size distribution of the dispersoids for various systems.