Investigation of a discus-milling process using a powder mixture of Al and TiO₂

In this study, a powder mixture of Al and TiO₂ was employed to investigate the milling process in a discus mill. In this first report on this novel mechanical mill, several variables, including the milling time and powder charge and their effects on the microstructural evolution of powder particles, are monitored and studied. The study reveals that the dominant parameters of the milling process are the milling time and the starting powder charge, similar to the other high-energy ball-milling processes. The longer the milling time and the smaller the starting powder charge, the more homogeneous the mixing and the finer the microstructure of the powder particles. The reaction between Al and TiO₂ was not observed with a milling period as long as 6 hours, for the present materials. However, the reaction between Al and TiO₂, during the subsequent heat treatment, is influenced by the milling condition. The powders with the longer milling times and finer mixing microstructures also form a finer microstructure, after the reaction between Al and TiO₂ during heat treatment. The methods for achieving an optimal milling efficiency for the Al- TiO₂ system are discussed