Abstract: This paper presents the study of the influence of the solid-liquid interface morphologies on the as-cast microstructure and mechanical properties of a single crystal nickel-base superalloy. The results show that there is no γ/γ' eutectic in the sample solidified with planar solid-liquid interface morphology. When the solid-liquid interface morphology is turned into celluar, then coarse dendritic, and finally fine dendritic ones, the amount of γ/γ' eutectic becomes more and more, the size of γ' smaller and smaller, and the shape of Y' more and more regular. The sample solidified with fine dendritic solid-liquid interface morphology has the longest rupture life, the sample with coarse dendritic solid-liquid interface morphology has has second longest rupture life, and the celluar structure has the shortest rupture life.

Key words: single crystal superalloy, solid-liquid interface morphology, dircetional solidif-ication, mierostructure and mechanical property