| About this Abstract |
| Meeting |
Materials Science & Technology 2019
|
| Symposium
|
Materials for Nuclear Applications
|
| Presentation Title |
Aging Behavior and Microstructure Evolution in Ni-Cr-Mo-W (Haynes 244) Alloy After Surface Treatment by Laser Shock Peening (LSP) |
| Author(s) |
Jie Song, Anurag Sharma, Seetha Mannava, Vijay Vasudevan |
| On-Site Speaker (Planned) |
Jie Song |
| Abstract Scope |
The Nickel base superalloy Haynes-244 (Ni-22.5Mo-6W-8Cr alloy) is used in high temperature environments because of its low thermal expansion coefficient with excellent mechanical properties and resistance to creep deformation and corrosion at elevated temperatures. The strengthening of this alloy is achieved by forming coherent intragranular Ni2(Cr,Mo,W) precipitates and intergranular μ phase during aging. The effects of LSP and post-aging on near-surface microstructure and properties were studied. Instead of Ni2(Cr,Mo,W), μ phase particles form evenly at the surface in γ matrix which leads to higher mechanical properties. The sub-surface has much denser intragranular Ni2(Cr,Mo,W) compared to traditional aging and regions far away from the surface show the traditional microstructure. The gradient microstructure after aging has been found to be mainly attributed to the LSP process, which can introduce higher plastic strain at the surface and promote μ phase formation. The effects of such gradient precipitate microstructures on properties will be discussed. |