Development of ODS vanadium alloy and irradiation effects on its properties

A new mechanical dispersion process to produce oxide dispersion strengthened (ODS) vanadium alloy has been successfully developed. In order to study effects of irradiation on microstructural evolution in ODS V alloy and unalloyed V, transmission electron microscopy observation and Vickers microhardness test were performed. ODS V alloy has five times as large Vickers microhardness as unalloyed V. ODS V alloy has twin structure. After irradiated with 3MeV Au²⁺ ions up to 1.5x10²⁰ ions/m² (about 60 dpa) at 813 K, microcrystalline transformation and defect clusters were observed in unalloyed V. On the other hand, the twin structure was stable in ODS V alloy. After irradiated up to 6.0x10²⁰ ions/m² (about 250 dpa), many microvoids were observed in unalloyed V, while the twin structure in ODS V alloy was disappeared. However no voids could be observed in ODS V alloy. Postirradiation anneal hardening was observed in unalloyed V after irradiated by neutrons up to 8.3x10²² n/m² (E_n > 1 MeV, 144 h). Nevertheless no radiation anneal hardening could be observed in ODS V alloy. Therefore ODS V alloy has a significant resistance to irradiation damage. (author)