Peritectic reaction during directional solidification in a Ru-containing nickel-based single crystal superalloy

ABSTRACT The peritectic reaction L + β-NiAl → γ′ during directional solidification in a Ru-containing nickel-based single crystal superalloy was investigated by the planar interface solidification and the phase transformation process was clarified in detail. The phase transformation mechanism of the peritectic reaction was further studied in the combination of the transmission electron microscope and the edge-to-edge matching model from the crystallographic point of view. The results indicated that the relaxation of some atoms on the matching planes (1 1 0)β and (1 1 1)γ′ maximized the atomic matching at the interface, increasing the possibility of peritectic γ′ phase nucleated on primary β-NiAl phase in the peritectic reaction.