Void swelling resistance of high-nickel alloy during irradiation

Inoue, Toshihiko; Yamashita, Shinichiro; Yamagata, Ichiro; Kaito, Takeji; Ioka, Ikuo

no journal, , 

Precipitation-strengthened high-nickel alloys have been developed for fast reactor fuel cladding material because of their intrinsic good dimensional stability. Nimonic PE16 is known as the representative high-nickel alloy, and it is a material strengthened by an intermetallic compound such as ordered phase -prim (Ni (Ti, Al)) formed in the matrix. The most important issue in development of high-nickel alloy is considered to be the improvement of mechanical properties at elevated temperature: the significant ductility is lost due to irradiation at high temperature. The cause of this problem was believed to be the re-distribution of ordered phase -prime and solute segregation to defect sink sites, such as grain boundary, dislocation and void surface, during irradiation. In this study, several types of precipitation-strengthened high-nickel alloys were developed and then the phase stability (precipitate stability and swelling resistance) in these alloys during irradiation was evaluated by using TIARA facility. The void swelling of 15Cr-35Ni-28, which is the high-nickel alloy with a same chemical composition of 15Cr-35Ni and 10% cold working, is lower than that of 15Cr-35Ni. It is considered that the effect of cold working improves its void swelling resistance and that dislocations induced by cold working would be effective sink sites for point defects.