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 H-3(+)). In the carbon concentration in the ion beam of similar to0.1%, no significant blisters were formed on the surface. However, many blisters of various sizes (from 1.0 mum to several hundred mum) were formed with carbon concentration of similar to0.7%. 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 mum to several hundred mum in diameter. For the recrystallized W and La2O3-doped W, blisters are irregular shapes, whose sizes are almost the same from 20 to 50 mum in diameter. These similarities in blister shapes could be related to microstructure of the samples. (C) 2004 Elsevier B.V. All rights reserved.