Blister formation and deuterium retention on tungsten irradiated by low energy and high flux deuterium plasma

Deuterium ion irradiation has been carried out with incident energies of 100 eV and flux of 1 × 10²² D⁺m^-2s^-1 at a temperature in range between 333 K and 1130 K up to a dose of 1 × 10²⁶ D⁺m^-2. Three kinds of tungsten used are pure tungsten made by powder metallurgy tungsten (PM-W), vacuum plasma spray tungsten (VPS-W) and single crystal tungsten (SC-W). Surface morphology before and after the irradiation is observed with a SEM. Retention property of deuterium after the irradiation is also examined with a TDS. Blisters with a diameter of about 0.2-2.0 μm are formed on PM-W by deuterium irradiation at 333 K and 673 K but size and shape of those blisters change depending on the irradiation temperatures. However, no blisters are found on PM-W at elevated temperatures between 723 and 1130 K. On the other hand, blisters with a diameter of about 2 μm are formed on SCW irradiated at 343 K but no blisters are observed on SCW irradiated at 383, 623 and 1123 K. In the case of VPS-W irradiated at 333, 723 and 1123 K, modification like blister with a diameter of about 0.2 μm occurs. TDS measurement also shows that deuterium is not retained in sample, which the blisters are not formed.