Effect of electromagnetic stirring on orientation distribution function of primary solid phase of Al-Cu alloy

Abstract

In this study, the orientation distribution function (ODF), which can be calculated from the pole figure data, was examined and tried in order to characterize the bulky morphology of primary solid phase of semi-solid slurry instead of erroneous 2D observation for the characterization of microstructure. Al-15wt%Cu alloys were electromagnetically stirred during the continuous cooling in the specially designed electromagnetic (EM) stirrer, which generates a rotating magnetic field, and the samples were prepared by interrupt-quenching semi-solid slurry at a solid-liquid region. Owing to EM stirring the temperature distribution of melt inside a crucible became uniformed compared with the case of unstirred melt and the normal dendritic structure was transformed to one consisting of the spherical and rosette shaped primary solid phase due to the fragmentation of the dendrites. Also by the effect of EM stirring the < 110 >//ND texture were still strongly developed, but the advancement of the orientations to lead < 110 >//ND texture became weaker, and the orientations to lead < 100 >//ND and < 111 >//ND texture were more strongly advanced in comparison with the unstirred case. Therefore the advancement of the texture became weak and so the tendency to random orientation was appeared due to the EM stirring. Therefore it was thought that the extent of random orientation could be valued for the characterization of bulky morphology of primary solid phase of semi-solid slurry.