Characteristics of U_3Si and U_3Si_2 Powders Prepared by Centrifugal Atomization

摘要

The characteristics, that is, morphology, size distribution, alloy phase and microstructure of U_3Si and U_3Si_2 powders, solidified rapidly by a centrifugal atomization, were investigated. The atomized powders consist of spherical particles with a relatively narrow size distribution independent of the alloy composition. The particle size distribution can be controlled by adjusting the atomization parameters such as feeding rates of the melt and revolution speeds of the disk. The major phases of atomized U_3Si and U_3Si_2 powders are α-U and U_3Si_2 and U_3Si_2, respectively. The atomized U_3 Si powder has a dendritic structure of very fine and non-faceted U_3Si_2 precipitates with less fibric and eutectic U_3Si_2 structure. The microstructure of U_3Si_2 powder shows a cellular structure with fine U_3Si_2 grains and finely dispersed silicon-rich precipitates. The time for complete peritectoid reaction of the atomized U_3Si particles and the resulting grain size are greatly reduced, due to the refinement of primary U_3Si_2 precipitates.