Irradiation hardening behaviors of large-scale hot rolling potassium-doped tungsten alloy under synergistic irradiations of Fe11+ ion combined with deuterium and helium plasmas

In this study, a 25 kg potassium doped tungsten (KW) plate dispersed K bubbles was prepared by hot rolling firstly. In order to evaluate the mechanical properties of KW after irradiation, the synergistic irradiation of Fe11+ ion, He and D plasmas were performed on KW and pure tungsten (PW). 3.5-MeV Fe11+ ion irradiation was used to simulate displacement damage induced by neutrons. The total fluence and irradiation temperature were 5.31 x 10(14) m(-2) for 0.5 displacements per atom (dpa) damage and 400 K, respectively. Positron annihilation Doppler broadening spectrometry (PA-DBS) technique was applied to measure the type of defect in both undamaged and damaged PW & KW samples. The total ion fluence helium (He) and deuterium (D) were kept constant at 1 x 10(25) He m(-2) and 5 x 10(24) D m(-2), separately. Subsequently, the hardness value of PW and KW received from CSM nanoindentation technique was analyzed and compared. The results show that the increase of vacancy-type defects in KW is restrained after irradiation compared with PW. For un-irradiated PW and KW samples, there are almost the same pop-in events, which indicate that PW and KW a similar plastic deformation at room temperature. The KW shows a better irradiation hardening resistance than PW under the same irradiation condition. Besides, the evolution of irradiation hardening as well as their relationship with K bubbles were discussed in detail.