Gamma prime hardened nickel-iron based superalloy

Claim 1

A gamma prime strengthened and solid solution hardened nickel-iron base alloy useful for fast reactor duct and cladding applications, the composition of said alloy imparting improved resistance to swelling in a neutron irradiation environment to said alloy, consisting essentially of from about 7.0 weight percent to about 10.5 weight percent chromium, from about 24 to about 35 weight percent nickel, from about 2.0 to about 3.3 weight percent molybdenum, from about 1.7 to about 2.5 weight percent titanium, from about 0.3 to about 1.0 weight percent aluminum, from about 0.5 to about 1 weight percent silicon, from about 0.03 to about 0.06 weight percent carbon, a maximum of about 2.0 weight percent manganese, and the balance iron, wherein said low chromium concentration range inhibits the formation of the detrimental sigma phase, and said silicon concentration range acts as a swelling inhibitor to the low chromium and low to intermediately low nickel range, which nickel composition range minimizes neutron absorption, and said molybdenum concentration range inhibits Laves phase precipitation induced by neutron irradiation, and wherein said alloy swells less than 0.3% at the peak swelling temperature of 538° C. at the fluence of 2.2 × 10 22 n/cm 2 (E > 0.1 MeV), and wherein said alloy exhibits an ultimate tensile strength in the range of about 90 to 100 ksi at 650° C.