Influence of Heat Treatment on γ Phase and Property of a Directionally Solidified Superalloy

Abstract

The effects of heat treatment process on microstructure and properties of a nickel base superalloy are investigated. The size of γ phase decreases and the stress rupture life of alloy at 1100 °C/60 MPa drops with the rise of cooling rate. The hardness at room temperature also increases. The size of cuboidal γ precipitate and the volume of spherical γ precipitate increase with the rise of aging temperature. With higher aging temperature, the alloy exhibits bimodal γ phase. A reasonable combination of the size and volume fraction of cuboidal and spherical γ phase can obtain better stress rupture property at 1100 °C/60 MPa.