| About this Abstract |
| Meeting |
10th International Symposium on Superalloy 718 and Derivatives (2023)
|
| Symposium
|
Superalloy 718 and Derivatives
|
| Presentation Title |
Characterization of γ′ Precipitation Behavior in Additively Manufactured IN738LC Superalloy via In-situ Small-angle Neutron Scattering |
| Author(s) |
Hailong Qin, Ying Tao, Songyi Shi, Hongyao Yu, Jinli Xie, Zhongnan Bi |
| On-Site Speaker (Planned) |
Hailong Qin |
| Abstract Scope |
IN738LC is a typical high-end Ni-based superalloy developed to meet the needs for harsh working environment (~980 ℃). The total amount of Al and Ti in its composition is over 6.8 wt%, which cause the intensive susceptibility to strain age cracking (SAC). Particularly, γ′ phase precipitates rapidly during the subsequent heating process, resulting in the volume shrinkage and local stress concentration.
In the present study, quantitative evaluation of the size and volume fraction of γ′ particles have been studied f by Small-Angle Neutron Scattering (SANS) and FE-SEM in additively manufactured IN738LC Superalloy employing isothermal heat treatment conditions of 850 ℃. The results shows that there is no observable γ′ precipitation in the as-deposited alloy, while a large number of small cellular and striated sub-structures can be characterized with widths ranging from 0.5 to 1.5 μm. During the 850 ℃ isothermal heat treatment, the γ′ phase rapidly precipitates in large quantities and shows a unimodal irregular sphere-like shape. The average size of the γ′ particles increase on prolonging the time: After isothermal heat treatment for 10 min, the average particle size is 72.5 nm; and it reaches 137.3 nm when ageing time is 120 min. However, the volume fraction of γ′ phase do not change with the extension of isothermal heat treatment time, which reaches about 40% after 10 minutes, which is quite different from that prepared by traditional casting process.
Key words: Small-Angle Neutron Scattering, IN738LC; Precipitation behavior; Additive manufacturing. |
| Proceedings Inclusion? |
Definite: At-meeting proceedings |