Effect of Solid Solution Treatment on Microstructure and Mechanical Properties of DS Superalloy DZ8

Abstract

The microstructure of DZ8 after solid solution treatment at 1260 ℃ and 1240 ℃ was observed, and the tensile and stress rupture properties were compared. The results show that less than 1% γ+γ' eutectic remains in the microstructure of DZ8 after solid solution treatment at 1260 ℃, while incipient melting takes place in the Hf-rich phase; about 12% γ+γ' eutectic exists in the microstructure of DZ8 after solid solution treatment at 1240 ℃, but no incipient melting phase is discovered. After solid solution treatment at 1260 ℃, the stress rupture property of DZ8 in 980 ℃/725 MPa and the tensil property of DZ8 at room temperature, 700 ℃ and 980 ℃ show little different compared with those treated at 1240 ℃, but the stress rupture property in 760 ℃/725 MPa decreases to some extent.

Keywords

• solid solution temperature
• microstructure
• mechanical property
• directionally solidified superalloy