Effect of Direction of Floating Zone Travel on the Mosaic Structure of Fe3% Si Alloy Single Crystals

Abstract

AbstractA pronounced influence of the molten zone stability on the dislocation substructure of as grown single crystals is found in Fe–3% Si alloys. In single crystals prepared by downward zoning the density of dislocations was ≅ 3 · 105 cm−2 and no local changes of mosaic structure are observed. On the other hand in single crystals prepared by upward zoning, where the molten zone is less stable than in the first case, considerable local changes in size and disorientation of mosaic blocks are found, crosswise and especially along the single crystals axis. The density of dislocations along the axis varied from ≅ 1 · 106 cm−2 to ≅ 3 · 106cm−2. The difference may be explained by dislocation generation due to the change of concentration gradients of impurities and due to the change of temperature gradients. Both are higher in crystals prepared by upward zoning than in those prepared by zone moving in the opposite direction.