About this Abstract |
Meeting |
2021 TMS Annual Meeting & Exhibition
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Symposium
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Materials for High Temperature Applications: Next Generation Superalloys and Beyond
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Presentation Title |
Microstructural Evolution under Complex Stress States during Creep of Single Crystal Ni-base Superalloy CMSX-4 |
Author(s) |
Nicolas Karpstein, Malte Lenz, Jonathan Cormier, Erdmann Spiecker |
On-Site Speaker (Planned) |
Nicolas Karpstein |
Abstract Scope |
We have investigated the microstructural evolution in monocrystalline CMSX-4 creep specimens with V-shaped geometry developed and tested in [001] direction (1093 °C) by Caccuri et al. (https://doi.org/10.1016/j.matdes.2017.06.018). The specific shape causes complex tensile and compressive stress states within one specimen. After 5 h, the region under compressive stress is still in a much earlier incubation stage of creep, as evident from extent of rafting and defect activity. Characteristic defect configurations were investigated by TEM on lamellas from specific locations and orientations. On the compressive side, dislocations display a much lower density and more clustered distribution throughout the matrix; interface networks have not yet restructured to more misfit-relieving configurations. In contrast, regions under tensile stress reached a steady-state creep regime with distinct rafting (N-type), which on the compressive side (P-type) is only observed after 24 h. These findings underline the importance of understanding complex stress states arising in superalloy applications. |
Proceedings Inclusion? |
Planned: |