Influence of crystal orientation on cellular growth of a nickel-base single crystal superalloy

The cellular pattern evolution during directional solidification of a nickel-base single crystal superalloy has been studied in different crystallographic orientations using re-oriented seed crystals. Under the same thermal gradient and solidification velocity, the microstructures of differently oriented cellular single crystals are schematically investigated. It is concluded that the cellular growth direction is less affected by the seed orientation and depends on the heat flow, and is usually along heat flow direction. Cellular interface stability and microstructure are greatly influenced by the crystallographic orientation. When increasing the misorientation, the cell spacing increases correspondingly and the cellular growth interface becomes more unstable.

► The cellular growth direction of nickel-base single crystal superalloys is along heat flow direction and less affected by the seed orientation.
► The cell tip growth is influenced by the crystal orientation and inclines to 〈0 0 1〉 direction.
► Larger misorientation increases the cell spacing and aggravates the instability of the cellular interface.