Large plastic deformation blistering and helium retention in 5% tantalum doped tungsten under 60 keV helium ions implantation

Tantalum (5 mass-% Ta) doped tungsten and pure tungsten in comparison were exposed to 60 keV helium ions implantation with a fluence of 1.04 x 10(22) ion m(-2). It was obvious that the W-5%Ta featured large plastic blisters both in number and in size were significantly reduced. The reason for this phenomenon was that vacancies and their complexes introduced by tantalum dopants reduced the diffusion coefficient of vacancy and vacancy-helium complexes. On the other hand, tantalum formed atomic clusters in the tungsten matrix, becoming a second phase with higher helium trapping ability, which inhibited migration and growth of helium bubbles, preventing the formation of large helium bubbles. Furthermore, helium ions form HenTakVm complexes in W-5%Ta during 60 keV helium ions implantation, which affected the characteristics of gas release in tungsten and the helium retention of W-5%Ta was larger than pure W.