Evidence for Transitions from Lateral to Continuous and to Rapid Growth in Ge-1at%Si Solid Solution

The interrelationship "undercooling-growth velocity-solidified structure" was studied for Ge-1at%Si solid solution. Three structural morphologies, faceted twins, coarse dendrites and refined equiaxed grains, were observed in a wide range of undercoolings from 80 to 394 K achieved by a levitation technique. Corresponding to low, intermediate and high undercoolings, these types of microstructures originated from lateral, continuous and rapid...