About this Abstract |
Meeting |
Superalloys 2024
|
Symposium
|
Superalloys 2024
|
Presentation Title |
B-4: Improvement in Mechanical Properties of Ni-base Superalloy Alloy247 Using Hot Forging |
Author(s) |
Shintaro Yoshimoto, Yuhi Mori, Masahiro Hayashi, Takashi Shibayama, Takeshi Izumi, Shinya Imano |
On-Site Speaker (Planned) |
Shintaro Yoshimoto |
Abstract Scope |
To improve the low-cycle fatigue (LCF) strength of Alloy247, refinement of the alloy microstructure through the forging process has been trialed and the mechanical properties and microstructure of the forged alloy were compared with that of the conventional casted alloy. By utilizing the MH (Mitsubishi Hitachi) process, an ingot of Alloy247 with high volume fraction of γ' phase was successfully forged without cracking. In contrast with cast Alloy 247, forged Alloy247 exhibited uniform microstructure with γ' precipitates, the grain size was significantly reduced from 10mm in the cast alloy to 200 mm in the forged alloy, and the eutectic structure was eliminated completely. Results obtained from high temperature tensile testing showed remarkable improvement in elongation which led to higher ultimate tensile strength (UTS) values. Owing to the fine microstructure, forged Alloy247 showed 15 times longer LCF life than that of the cast alloy although creep strength slightly decreased in low stress regions. Significant improvement in LCF life of Alloy247, which has intrinsically high creep strength, allows for tuning of the mechanical properties based on requirements and broadens the application of the alloy to hot section parts. |
Proceedings Inclusion? |
Definite: At-meeting proceedings |