D. Pan, S. Zhou, Z. Zhang, M. Li, H. Li, Y. Wu
April 3, 2017
Primary particles with faceted cubic morphology were produced in as-cast Al-Mg alloy due to the addition of Sc. The cross-section of the particles revealed some eutectic structure composed of multilayer of ‘Al 3 Sc + α-Al + Al 3 Sc····’. At the cooling rate of 200 – 300 K/s, Al 3 Sc primary phase nucleated initially on oxides within the melt and developed to a cubic structure with a ‘cellular-dendritic’ mode of growth. The formation of α-Al structural shells was attributed as a reason for the segregation of Mg-rich lamellar dendrites at later stages. A growth mechanism for multilayer structure was proposed using the results presented.