Effects of heat treatment on microstrucutures of a Re-containing Ni-based single crystal superalloy

Abstract

Effects of heat treatment on microstrucutures of a Re-containing single crystal superalloy have been investigated. The results showed that (γ+γ′) eutectic in as-cast alloy is practically dissolved with solution heat treatment, and the degree of segregation is distinctly decreased. The size, morphology and distribution of γ′ phase are mightily affected by the first-stage ageing treatment temperature. When the first-stage ageing treatment temperature lower than 1160°C, the shape of the γ′ phase is cubic. But the γ′ phase shape is transformed to sphericity when the temperature higher than 1180°C. The γ phase channel width is significantly increased, and the fine γ′ phase precipitated in the γ phase matrix channel.