Research progress on the formation, regulation, and failure mechanisms of the γ′ phase in nickel-based superalloy

Ni-based superalloys represent a critical class of advanced materials in modern industry especially for the fabrication of hot-section components in aero-engines and aerospace propulsion systems. These alloys typically exhibit excellent oxidation resistance, creep resistance and corrosion resistance under high-temperature conditions, making them a cornerstone of modern industrial technology. The performance of Ni-based superalloys lies in controlling their precipitation phases. Common precipitations include γ′ phase, γ′' phase, carbides, and TCP phases, where the γ′ phase serves as the primary reinforcing phase. The size, morphology, distribution, and volume fraction of γ′ precipitates strongly influence creep resistance, strength, and deformation behavior. Existing studies have generated substantial knowledge on alloy design, processing, and service behavior. However, a γ′-centered synthesis that integrates precipitation, regulation, and degradation remains limited. This paper comprehensively reviews the precipitation mechanisms of the γ′ phase in Ni-based superalloys, the factors affecting its characteristics, and its failure behavior under service conditions. The aim is to clarify the role of the γ′ phase in these alloys and to provide theoretical guidance for their further development.