About this Abstract |
Meeting |
2020 TMS Annual Meeting & Exhibition
|
Symposium
|
Materials Design Approaches and Experiences V
|
Presentation Title |
Precipitate-mediated Dislocation Transformer in Ni-base Superalloys |
Author(s) |
Longsheng Feng, Michael J Mills, Yunzhi Wang |
On-Site Speaker (Planned) |
Longsheng Feng |
Abstract Scope |
It is our conventional wisdom that dislocations would not change their Burgers vectors in a shearing event. But in the γ”-strengthened Ni-based superalloys, the low-symmetry intermetallic (γ”, DO22) precipitates embedded in the γ matrix (FCC) would serve as a transformer to constantly transform <110>/2 dislocations into <112>/6 Shockley partials that are not the two partials associated with the <110>/2 dislocations. This discovery is made by computer simulations using the microscopic phase field model with ab initio calculations of the generalized-stacking-fault-energy (GSFE) surfaces as inputs. The transformed dislocation contents would therefore significantly change the deformation pathway and hence impact the strengthening effects. The constant production of Shockley partials may be responsible for the prevailing microtwinning in Alloy 718 that is strengthened mainly by γ” precipitates. This work is supported by NSF under DMREF program. |
Proceedings Inclusion? |
Planned: Supplemental Proceedings volume |