Abstract: Tungsten (W) is a promising candidate material for plasma-facing components (PFC) in tokamak fusion devices because of its high melting point, thermal conductivity, and sputtering threshold. However, the drawbacks in its mechanical properties, such as low recrystallization temperature and high ductile-to-brittle transition temperature, limit its applications in long-term operated fusion reactors. In the past decade, the Radiation Surface Science and Engineering Lab (RSSEL) has been developing dispersion-strengthened tungsten (DS-W) alloys as an alternative PFC W-based material. DS-W alloys are fabricated with 0.5 to 10 wt.% added carbide dispersoids via spark plasma sintering. Compared to pure W, initial testing has found that DS-W alloys possess increased recrystallization temperature and improved ductility. This talk will introduce recent efforts in RSSEL on DS-W with a focus on their response to helium (He) irradiation, which could result in the formation of He bubbles and the consequential degradations of mechanical, thermal, and surface properties of W materials. We showed that the chemical composition of carbide dispersoids played a critical role in tuning the He behaviors in DS-W. The bubble formation was successfully suppressed in certain types of DS-W. In addition, microscopy characterization using atom probe tomography and scanning transmission electron microscopy will be applied to investigate the interactions between He bubbles and the alloy matrix. Our study will provide a new avenue to designing W alloys with superior tolerance to He irradiation by optimizing the dispersoid concentration and distribution.
Biosketch: Dr. Xing Wang is an Assistant Professor in the Ken and Mary Alice Lindquist Department of Nuclear Engineering at the Pennsylvania State University (PSU). His research focuses on understanding material behaviors in extreme environments by combining advanced microscopy characterization and multiscale material modeling. He is now collaborating with Prof. Jean Paul Allain at PSU on developing DS-W alloys as future PFC materials. Xing received his B.S. from Tsinghua University in Engineering Physics and Ph.D. from the University of Wisconsin-Madison in Nuclear Engineering. Before joining PSU in 2020, he was a postdoctoral research associate at the Center for Nanophase Materials Sciences in Oak Ridge National Laboratory.
All faculty, students, and guests are welcome to attend this virtual event.
Date(s) - Dec 03, 2021
3:00 pm - 4:00 pm
Prof. Xiang Wang Seminar