| About this Abstract |
| Meeting |
MS&T22: Materials Science & Technology
|
| Symposium
|
Advanced Characterization of Materials for Nuclear, Radiation, and Extreme Environments III
|
| Presentation Title |
Elucidating Helium Induced Softening in Nanograin Tungsten Through Electron Microscopy Informed Synchrotron X-Ray Scattering |
| Author(s) |
W. Streit Cunningham, Cormac Killeen, Yang Zhang, David Sprouster, Osman El Atwani, Jason Trelewicz |
| On-Site Speaker (Planned) |
Jason Trelewicz |
| 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. Hardness and modulus are mapped as a function of irradiation temperature and fluence in two different tungsten microstructures via nanoindentation. Scaling behavior is explained based on the helium cavity microstructure, which is characterized through transmission electron microscopy informed synchrotron x-ray scattering experiments. We show that 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 cavity induced hardening. Insights from molecular dynamic simulations demonstrate that the observed softening can be attributed to enhanced strain accommodation within the helium loaded grain boundaries. |