Growth of Equiaxed Dendrite in Al-20wt.%Cu Alloy by Synchrotron X-Ray Radiography

Synchrotron X-ray radiography was used to in-situ study the growth of equiaxed dendrite during the solidification of Al-20 wt.% Cu alloy. Equiaxed dendrites with two different morphologies were formed in nearly isothermal conditions. The image processing was used to improve the image quality. The time evolution of the primary dendrite arm length and the corresponding growth rates were analyzed. The experimental results indicated that the solute interaction was the main factor to influence the equiaxed dendrites growth. Besides, the rotation and floating of the dendrites were also observed during the early growth phase.