Ion-induced spinodal-like decomposition of Fe-Ni-Cr invar alloys

Abstract It was recently discovered that Fe-Cr-Ni alloys with (35 ± 10)wt.% nickel decompose in a spinodal-like manner when irradiated with fast neutrons. This unexpected decomposition has many consequences. Not only do the anomalous properties characteristic of the Invar compositional regime disappear, but pronounced changes occur in both tensile properties and void swelling. Ion bombardment experiments have also been used to study void swelling and are now being used to study the decomposition. Microscopy and EDX examination of specimens employed in earlier void swelling studies confirm that ion irradiation induces spinodal-like decomposition in these alloys. The period and amplitude of the compositional fluctuations induced by radiation are sensitive to temperature, nickel content and perhaps crystallographic direction, but are not very sensitive to chromium content or displacement rate.