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

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 6.4MeV Fe 3+ ions at 500°C up to 10dpa. Dual-beam irradiation of Fe 3+ ions and energy-degraded 1MeV 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. [doi:10.2320/matertrans.MG201212] (Received October 19, 2012; Accepted December 17, 2012; Published February 16, 2013)