Surface modification and deuterium retention in hot-rolled potassium doped tungsten alloy exposed to deuterium plasma

A 25 kg potassium doped tungsten (KW) plate dispersed with ∼71 nm K bubbles was prepared by hot rolling firstly. In order to evaluate the radiation resistance of KW, the surface blistering and deuterium (D) retention were investigated on KW and pure tungsten (PW), which were exposed to low-energy (50 eV) and high-flux (∼10²² D m⁻² s⁻¹) D plasmas at 523 K and 573 K to a fluence of 1.08 × 10²⁶ m⁻². After irradiation, D desorption information of all the irradiated samples were measured by thermal desorption spectroscopy (TDS). The results indicate that severe blistering occurs on both PW and KW under different irradiation conditions. Compared to PW, KW tends to form more but smaller blisters on the surface. Nevertheless, the blistering area ratio of KW is comparable with that of PW. In addition, the blisters prefer to form on those grains with surface orientation close to (111). In terms of D retention, compared with PW, the total D retention of KW increases by a factor of ∼ 2.5 under both irradiation conditions. The present results indicate that the presence of K bubbles will increase the D retention. The reasons for the difference in surface morphology evolution and total D retention of PW and KW are discussed in detail.