Modification of the Structure of the Hypereutectic Silumin Alloy Al-44Si under the Action of Compression Plasma Flows

Abstract

The effects of high-energy compression plasma flows on the structure, elemental composition, and phase state of Al–44 at % Si hypereutectic silumin alloy have been investigated. Using scanning electron and optical microscopy it was found that a decrease in grain size of both primary silicon particles and Al–Si eutectic components occurs with an increase in absorbed energy density of compression plasma flows. The primary silicon crystals were dispersed down to 300 nm as a result of the high cooling rate of the melted layer after its homogenization by means of hydrodynamic mixing. It was found that, with the increase in the absorbed energy density, homogenization of the elemental composition in the modified layer occurs owing to an increase in the lifetime of the melted state and a more efficient mixing process.