Microstructure development of different orientated nickel-base single crystal superalloy in directional solidification

Single crystal superalloy AM3 oriented along <001> and <011> lattice directions with a deviation were produced by the bottom seeding technique in a modified Bridgman directional solidification furnace. It was found that differently oriented seeds resulted in different dendritic structures. The dendrites of the crystal with <011> orientation arrayed in rows in transverse microstructure. The inclined primary dendrites grew along their initial crystallographic direction irrespective of heat flow direction. As the deviation angle was increased to 17°, the orientation of the crystal changed from <001> to <011>. In addition, crystal growth orientations could affect the primary dendrite arm spacings.