一种新型镍基变形高温合金“孪晶+γ′相”组织调控及高温力学性能研究

Abstract:

In this study, the "twin + γ′ phase" composite structure was constructed in a novel Ni-based wrought superalloy by means of thermomechanical treatment, and the evolution of twin and γ′ phases was investigated by using EBSD and SEM. Meanwhile, the high temperature mechanical properties of the alloy at 760 ℃ were studied. The results show that the "twin + γ′ phase" composite structure can effectively improve the high temperature mechanical properties of the alloy, and with the increase of the length fraction of the annealing twin, the thickness of the twin lamellar increases, and the high temperature strength of the material decreases; When the rolled alloy (ε=68%) is annealed at 1120 ℃ for 15 min and subjected to two-stage aging treatment (650 ℃/24 h/AC and 760 ℃/16 h/AC), the length fraction of twins in the "twin + γ′ phase" composite structure is 25.38% and the average size of γ′ phase is 32.21 nm. The yield strength of the alloy increased from 775 MPa to 1184 MPa, and the elongation after fracture increased from 3.18% to 18.96%. By constructing the "twin + γ′ phase" composite structure can effectively improve the high-temperature mechanical properties of the alloy, which provides a novel strategy for improving the high-temperature mechanical properties.

Key words:novel Nickel-base wrought superalloy;