Long-Period Superlattices of γ' Phase in Ni-Based Superalloy

Abstract

Nanoscale lamellar structure was discovered in L1₂-type γ'-Ni₃(Al, Ta) precipitate. This structure was characterized by TEM phase contrast of antiphase boundary (APB) composed of aligned {110} planes. Lamellar spacing corresponds to APB period. The strictly periodical APB formation can be attributed to the formation of long-period superlattices (LPSs), and period of LPSs is ten times larger than that in conventional LPSs. The zigzag lamellar shape after tensile test suggested that the additional external force is required for deformation, and strength could be improved by LPSs structure in the γ' phase.