Advantages of vanadium alloys for fusion reactor structural applications are: low induced activation, excellent thermal stress factor, high strength at elevated temperatures, and superior ductility at low temperatures. Resistance to irradiation damage is also very impressive, i.e. very small DBTT shift by irradiation and low swelling. Research and development of vanadium alloys have made a remarkable progress in recent years partly supported by ITER-related activities. Composition range centered about V-4Cr-4Ti is the target of many of the studies conducted in the US, Japan and RF. Most of the studies have demonstrated the superior performance of this alloy family, while some alloys containing large amount of impurities have shown relatively poor properties. In addition to the baseline mechanical properties, neutron irradiation effects, e.g., swelling and radiation embrittlement are covered in this paper. Of particular importance is the study on the effects of dynamically-charged helium on mechanical properties and swelling. Recent developments of insulator coatings and welding are also covered. The importance of mechanistic studies of the damage behavior is emphasized for efficient alloy development and prediction of materials life in service.

Vanadium alloys have been identified as a leading candidate material for fusion first-wall/blanket applications. Certain vanadium alloys exhibit favorable safety and environmental characteristics, good fabricability, high temperature and heat load capability, good compatibility with liquid metals and resistance to irradiation damage effects. The current focus is on vanadium alloys with (3-5)% Cr and (3-5)% Ti with a V-4Cr-4Ti alloy as the leading candidate.iThe available data base indicates that the V-Cr-Ti alloys provide the following advantages:• These alloys are readily formable and weldable; however, atmospheric contamination must be avoided during welding and high temperature processing.• The relatively high thermal conductivity and low thermal expansion provide for a high heat load capability.• These alloys exhibit _'ioodhigh temperature tensile and creep properties which permit high temperature operation.

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