GH4698合金微观组织调控机制与中温力学行为研究

Microstructure Regulation Mechanisms and Intermediate Temperature Mechanical Behavior of GH4698 Alloy

摘要:

设计了不同的热处理制度，通过SEM、EDS、TEM以及拉伸实验等方法研究了不同制度下GH4698合金的组织演变及750 ℃拉伸性能，为合金微观组织调控和力学性能优化提供参考。结果表明：多级热处理制度使合金中γ′相尺寸呈多峰分布，其中小尺寸γ′相对合金强度有利，大尺寸γ′相利于提高合金塑性。在750 ℃下，经1030 ℃/4 h, AC+1000 ℃/4 h, AC+875 ℃/16 h, AC+725 ℃/16 h, AC热处理的合金析出3种尺寸的γ′相，合金晶内与晶界的强度得到协调，促进了位错滑移的传递，使合金塑性提升，具有最佳的综合力学性能，抗拉强度为706 MPa，断后伸长率达到9.3%。

Abstract:

Diverse heat treatment schedules were designed and their effects on microstructural evolution and tensile properties at 750 ℃ were investigated by SEM, EDS, TEM, and mechanical testing. The results demonstrate that multi-stage heat treatment schedules lead to a multi-modal size distribution of γ′ precipitates within the alloy, where fine γ′ precipitates contribute to strength, while coarse γ′ phases enhance ductility. At 750 ℃, the alloy subjected to the heat treatment of 1030 ℃/4 h, AC+1000 ℃/4 h, AC+875 ℃/16 h, AC+725 ℃/16 h, AC develops a trimodal γ′ phase distribution. This microstructure balances the strength between intragranular and grain boundary regions, facilitating the transfer of dislocation slip and enhancing the ductility of the alloy. The alloy exhibits the best overall mechanical properties, with a tensile strength of 706 MPa and an elongation after fracture of 9.3%.