Effect of tungsten microstructure on blister formation by hydrogen and carbon mixed ion beam irradiation

Characteristics of blister formation for different types of tungsten (stress relieved W, recrystallized W, K-doped W, and La2O3-doped W) were studied by hydrogen and carbon mixed ion beam irradiation (1 keV H3+). In the carbon concentration in the ion beam of ∼0.1%, no significant blisters were formed on the surface. However, many blisters of various sizes (from 1.0 μm to several hundred μm) were formed with carbon concentration of ∼0.7%. These characteristics were observed for all samples. For the stress relieved W and K-doped W, blisters are round shapes, whose sizes ranged from 1 μm to several hundred μm in diameter. For the recrystallized W and La2O3-doped W, blisters are irregular shapes, whose sizes are almost the same from 20 to 50 μm in diameter. These similarities in blister shapes could be related to microstructure of the samples.