About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
Deformation and Transitions at Grain Boundaries VII
|
| Presentation Title |
Characterization of Strain at Twin Boundaries in Ni-base Superalloys via Dark Field X-ray Microscopy |
| Author(s) |
Sven E. Gustafson, Wolfgang Ludwig, Paul Shade, Diwakar Naragani, Darren Pagan, Michael Sangid |
| On-Site Speaker (Planned) |
Sven E. Gustafson |
| Abstract Scope |
Polycrystalline materials, specifically Ni-base superalloys, see common use in high temperature applications such as the turbine of jet engines. During cyclic loading, localization of intragranular strain due to crystallographic slip acts as a catalyst for crack initiation, often at coherent twin boundaries. In this work, a high-resolution characterization of a region near a twin boundary is presented of a polycrystalline Ni-based superalloy (LSHR) subjected to fatigue loading. Dark-field x-ray microcopy is used to directly measure the intragranular misorientation and elastic strain within a grain of interest with 200nm spatial resolution. The extreme strain gradients seen within the material validate those presented in a EVP-FFT crystal plasticity model and indicate the presence of high residual stress gradients approaching a coherent twin boundary. The present work shows that sub-surface, high-resolution, 3D data is necessary to help elucidate the deformation near grain boundaries and suggests the importance of strain gradients in deformation models. |
| Proceedings Inclusion? |
Planned: Supplemental Proceedings volume |