Precipitation Dynamics and Mechanical Properties Analysis of a Nickel-Based Superalloy Cooled Under Different Rates

The solid solution cooling heat treatment of powder, high-temperature alloys is a crucial part of the process for ensuring the strength of materials during the forging processing. The influence of the γ′ phase and other microstructures in high-temperature alloy forgings on their macroscopic mechanic...

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Bibliographic Details
Main Authors: Jinhe Shi, Liwei Xie, Shengyu Liu, Baojin Chen, Lei Zhao, Kailun Zheng
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Metals
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Online Access:https://www.mdpi.com/2075-4701/15/7/781
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Summary:The solid solution cooling heat treatment of powder, high-temperature alloys is a crucial part of the process for ensuring the strength of materials during the forging processing. The influence of the γ′ phase and other microstructures in high-temperature alloy forgings on their macroscopic mechanical properties has been confirmed in numerous studies. Among them, the performance of the γ′ phase during the solid solution cooling process varies significantly depending on the cooling rate. This study uses the FGH99 nickel-based high-temperature alloy as the research material. It examines the precipitation and microstructure evolution law of the material under different cooling rates and its impact on the macroscopic mechanical properties of the material. Additionally, a prediction model of the organizational properties based on the cooling rate is constructed. The research findings indicate that there is a distinct positive correlation between the yield strength of the material and the cooling rate. As the cooling rate increases, the yield strength rises from 910.8 MPa to 1025.4 MPa, showing an increase of 12.6%. Moreover, an increase in the cooling rate has an evident promoting effect on the refinement of the precipitation phase. When the cooling rate is elevated from 50 °C/min to 250 °C/min, the average size of the γ′ phase decreases from 106 nm to 82.1 nm, and its morphology transforms from an irregular state to a spherical shape. For the microstructure of the material, such as the size of the precipitated phase and dislocation density, the maximum prediction error of the heat treatment organization performance prediction model established in this study is 2.97%. Moreover, the prediction error of the yield strength is 1.76%.
ISSN:2075-4701