Effects of transition metal carbide dispersoids on helium bubble formation in dispersion-strengthened tungsten

Abstract

The formation of helium bubbles and subsequent property degradation poses a significant challenge to tungsten as a plasma-facing material in future long-pulse plasma-burning fusion reactors. In this study, we investigated helium bubble formation in dispersion-strengthened tungsten doped with transition metal carbides, including TaC, ZrC, and TiC. Of the three dispersoids, TaC exhibited the highest resistance to helium bubble formation, possibly due to the low vacancy mobility in the Group VB metal carbide and oxide phases. Under identical irradiation conditions, large helium bubbles formed at grain boundaries in tungsten, while no bubbles were observed at the interfaces between the carbide dispersoid and tungsten matrix. Moreover, our results showed the interfaces could suppress helium bubble formation in the nearby tungsten matrix, suggesting that the interfaces are more effective in trapping helium as tiny clusters. Our research provided new insights into optimizing the microstructure of dispersion-strengthened tungsten alloys to enhance their performance.

Compositionally complex carbide ceramics: A perspective on irradiation damage

“…Moreover, high-throughput computational and experimental tools may be needed to accelerate the evaluation of irradiation damage behavior from a large number of chemical compositions to down-select the promising CCC with maximum irradiation resistance. Furthermore, it will also need the design of "sinks" in their microstructures for the absorption and annihilation of irradiation defects, which may include the specific grain boundaries (e.g., incoherent twin boundaries 58 ) and nanoscale interfaces (e.g., metal/carbide 59 or carbide/oxide interfaces 60 ).…”