Effect of deuterium and helium plasma exposure on recrystallization in copper

Helium has been shown to effectively retard recrystallization and grain growth in tungsten for fusion application. However, it is unclear how hydrogen isotopes affect recrystallization, as their desorption temperature is far lower than the recrystallization temperature in tungsten, preventing them from remaining in the material and taking effect. Using rolled copper, this study investigated the effects of deuterium and helium plasma on recrystallization by leveraging the high deuterium desorption temperature in copper. Rolled copper samples exposed to deuterium or helium plasma were annealed at temperatures from 300 to 800℃. It was found that deuterium plasma exposure led to a slight retardation of the recrystallization but no impact on the grain growth. Helium plasma exposure promoted recrystallization but significantly inhibited grain growth, which is different from the effect in tungsten. This work offers preliminary insights into understanding the degradation of mechanical properties in copper-based materials with hydrogen isotopes and helium under high-temperature conditions for fusion applications.