About this Abstract |
Meeting |
2022 TMS Annual Meeting & Exhibition
|
Symposium
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Materials Systems for the Future of Fusion Energy
|
Presentation Title |
Grain Boundary Softening in Helium Implanted Fine-grained Tungsten |
Author(s) |
William Cunningham, Yang Zhang, Osman El-Atwani, Jason Trelewicz |
On-Site Speaker (Planned) |
William Cunningham |
Abstract Scope |
Relative to coarse-grained tungsten where helium bubbles promote classical irradiation hardening, ultrafine-grained tungsten experiences biased helium bubble formation at grain boundaries and reported softening. Here, we examine the influence of the helium cavity distribution on the mechanical behavior of fine-grained tungsten using targeted implantation studies. The hardness and modulus, along with helium cavity evolution, are mapped as a function of temperature and fluence in two different tungsten microstructures. At the lowest fluence, the formation of grain boundary cavities is correlated to a reduction in hardness, which is recovered with increasing fluence due to the formation of lattice dislocation loops. Insights from molecular dynamic simulations demonstrate that the observed softening can be attributed to enhanced strain accommodation within the grain boundaries. Specifically, helium bubbles undergo deformation and coalescence at reduced stresses, for which the latter is confirmed through post-mortem TEM imaging of helium bubbles within the plastic zone of residual impressions. |
Proceedings Inclusion? |
Planned: |
Keywords |
Nuclear Materials, High-Temperature Materials, Modeling and Simulation |