Ion-Irradiation Hardening of Brazed Joints of Tungsten and Oxide Dispersion Strengthened (ODS) Ferritic Steel

Abstract

Irradiation hardening and microstructural change of the brazed-joint of W and oxide dispersion strengthened ferritic steel (ODS-FS) was investigated by nano-indentation hardness test and transmission electron microscopy after ion irradiation with 6.4 MeV Fe³⁺ ions at 500°C up to 10 dpa. Dual-beam irradiation of Fe³⁺ ions and energy-degraded 1 MeV He⁺ ion was also carried out. A considerable irradiation hardening occurred in the W base metal where dislocation loops and nano-scaled voids or He-bubbles were observed. Dual-beam irradiation enhanced the hardening. No significant hardening was observed in ODS-FS. The hardness of insert material was reduced after irradiation, which is due to the recovery of dislocations generated during joining process.