Effect of pressure and gravitational field on the dendritic structure and distribution of solutes in Al-4% Cu single crystals

Abstract

Peculiarities of the formation of the dendritic structure and the development of alloying-component sedimentation in the Al-4% Cu alloy during its directional solidification under conditions of the earth gravitational field under pressure have been studied. It has been found that pressure substantially affects the development of alloy-component sedimentation in the two-phase zone in the case of the dendritic growth of a solid as well. The increase in the copper concentration near the lateral surface of the single crystal along the gravitational-field component, which was revealed when analyzing the nonuniformity of the solute distribution in transverse sections of a eutectic-phase sample, as well as the changes in the lattice parameter of the α solid solution, were found to be maximum during the solidification of the melt under a pressure of 0.25 and minimum under a pressure of 0.15 MPa.