Decreased surface blistering and deuterium retention in potassium-doped tungsten exposed to deuterium plasma following ion irradiation

Abstract

A large-size potassium-doped tungsten (KW) plate with a thickness of 15 mm was fabricated via powder metallurgy technology and hot rolling. In order to appraise the irradiation resistance of KW, the surface deuterium (D) blistering and D retention were studied on Fe11+ pre-damaged (0, 0.05 & 0.5 dpa) KW and pure tungsten (PW), which were exposed to ~60 eV and ~ 5 × 1021 m-2 s-1 D plasmas at 500 K to a fluence of ~ 5.76 × 1025 m-2. The results indicated that the KW alloy can inhibit the generation of vacancy defects after Fe11+ ion damage compared with PW because K bubbles can restrain the migration of W self-interstitial atoms and the accumulation of vacancies caused during Fe11+ ion irradiation. The Fe11+ ions pre-damage can relieve the surface blistering and D retention of PW and KW at the same time and the KW has a better effect on inhibiting D retention, while does not shows a significant advantage for inhibiting surface blistering compared with PW. Besides, the causes for the discrepancy in total D retention and surface morphology evolution of PW and KW were discussed in detail.