Commercially available cobalt-base alloys and five experimental compositions were surveyed for postirradiation tensile properties. These alloys are attractive for use as fuel claddings in an advanced liquid metal cooled fast breeder reactor.

It was found that cobalt-base alloys are susceptible to decreasing ductility with increasing deformation temperature after irradiation. The mode of failure at 800 C is grain boundary tearing similar to that observed in stainless steels and Ni base alloys. However, these alloys are potential fuel cladding materials at 650 C because of their much higher strengths than Type 304 stainless steels.