The Mössbauer Effect and the Anomalous Properties of the Invar Alloys

Abstract

In order to investigate the cause of anomalous properties of the γ-phase iron-nickel alloys with Invar compositions, the Mössbauer effect spectra of these alloys were measured as a function of temperature. Especially, the influences of phase mixture (α+γ), cold-work and external magnetic field were examined. From these measurements, it was concluded that there exist transition states between the α and γ phases, and they cause a diversity of hyperfine fields in the Invar-type alloy. Many hyperfine fields thus produced make the Invar alloy an assembly of various magnetic transition points, which, as a result, gives rise to the anomalies of physical properties.