Origin and specific features of invar anomalies of physical properties: Fe-Ni alloys with an FCC lattice

Abstract

In their physical properties, the γ-Fe-Ni alloys can be separated into three groups of materials: invars, high-nickel alloys, and medium-nickel alloys of the transition class. In the invars and alloys of the transition class in the temperature interval ΔT adjoining T C, a weak ferromagnetic state arises. In high-nickel alloys and transition alloys at temperatures below t f, a strong ferromagnetic state exists. The invar anomalies of physical properties in γ-Fe-Ni alloys are observed in the temperature range in which there occurs a transition from the weak ferromagnetic into strong ferromagnetic state.