*3.1. Comparison of the Surface Images*

Figures 10–12 (magnification 200 x) show that the 0g-sample shows larger dendrites (shows larger areas of the same repetitive patterns) with the similar orientation, while the 1g-sample shows multiple smaller dendrites that are randomly oriented.

Comparing the images of the 1g-Sample in Figures 11–13 (higher magnifications) one sees that there is only a little or no interdendritic phase. This could be an effect of gravity, which leads to a segregation of the solute phase downwards into the sample. In contrast, for the 0g-sample, there are no visible voids between the dendrite arms. The secondary dendrite arm spacings are similar. It is understandable, that not only the gravity but also the wetting of the solute phase with the solid dendrites influences the segregation of the solute phase. Hence, it might be of interest for further studies to vary the gravitational forces on the sample during solidification in a wide range between 0g and above 1g, in order to get a better understanding of the influence of gravity on this segregation effect.
