ANOMALOUS THERMODYNAMIC PROPERTIES OF IRON-NICKEL (FCC) ALLOYS

Anomalous behaviors are found in thermodynamic properties of FeNi (f.c.c.) alloys measured by the solid state electrolyte cell method at 900 to 1300 K. The alloys containing 20 to 50 at% Ni seem to have a tendency to split into two f.c.c. phases even at high temperatures. This is consistent with the fact that the composition dependence of physical properties, such as elastic moduli, electrical resistivity, and thermoelectric power, is also anomalous at high temperatures. The so‐called Invar problem may be closely related to this tendency. Copyright © 1979 WILEY‐VCH Verlag GmbH & Co. KGaA