Microstructure and γ′ phase evolution characteristics of novel nickel-based superalloy during compression

Abstract

In this paper, the dynamic recrystallization (DRX) mechanism, texture evolution and the effect of γ ′on the microstructure evolution of a new nickel-based superalloy at 1075 °C and strain rate of 0.01 s−1 were systematically investigated. The results showed that the DRX mechanism undergoes significant alterations with the increase of strain. When the strain is 0.07, the discontinuous dynamic recrystallization (DDRX) constitutes the dominant mechanism. As the strain increases to 0.13, the DDRX mechanism transforms into continuous dynamic recrystallization (CDRX), and the dynamic recrystallization (DRXed) grains grow when the strain is further increased to 0.20. The texture evolution indicated that with the increase of strain, the crystal orientation shifts from and to and , and texture intensity initially weakens and then strengthens, which is closely associated with the DRX mechanism. At a strain of 0.07, the texture is primarily influenced by the DRXed grains. As the strain increases to 0.13, the deformed grains become the dominant factor in determining the texture, and at a strain of 0.20, both the DRXed and deformed grains jointly dominate the texture. The CDRX mechanism facilitates the formation of and textures, while DDRX is mainly related to orientation. Additionally, due to the L12 ordered structure of the γ′ phase, dislocations and stacking faults gradually accumulate in the γ′ phase with the increase of strain, while the dislocation density in the γ matrix initially ascends and then descends.

Keywords

• Nickel-based superalloy
• thermal compression
• Dislocation density
• Recrystallization