About this Abstract |
Meeting |
2022 TMS Annual Meeting & Exhibition
|
Symposium
|
Deformation and Damage Mechanisms of High Temperature Alloys
|
Presentation Title |
Strengthening via Chemical Segregation to Deformation Twin Boundaries in Co-Ni-Cr-Mo Superalloy |
Author(s) |
Stoichko Antonov, Qing Tan, Baptiste Gault |
On-Site Speaker (Planned) |
Stoichko Antonov |
Abstract Scope |
The processing and deformation of low stacking fault energy superalloys leads to a characteristically high amount of micro and nano-twins. As these faults effectively obstruct the dislocation motion, the yield strength and ultimate tensile strength are significantly increased when compared to a twin-free microstructure. In this study, we show that a critically high density of twins can lead to a transformation of high angle grain boundaries to a Σ3n network structure. Interestingly, secondary hardening is observed during thermal exposure and the strengthening increment is increased by increasing Mo content. We use transmission electron microscopy and atom probe tomography to reveal Cr segregation to the deformation twin boundaries, which effectively further hinders dislocation motion and increases the strength at the expense of the ductility. Computational modeling was used to show that the Cr segregation reduces the twin boundary energy, however, Mo increases the propensity for Cr segregation. |
Proceedings Inclusion? |
Planned: |
Keywords |
High-Temperature Materials, Mechanical Properties, Characterization |