Thermal expansion of anti-invar alloys up to high temperatures

Abstract

The thermal expansion of the anti-invar alloys Fe–20Ni–6Mn, Fe–22Ni–3Cr–0.15C and Fe–14Ni–7Mn–0.6C which are used commercially as active side materials in bimetals was determined from RT up to 1500 K. All alloys show an enhanced thermal expansion coefficient, CTE, in the temperature range up to 1200 K with peaks around 500 and 1000 K. For T>1200 K d(CTE)/d T becomes negative, i.e., the CTE is smaller than the normal lattice expansion in this temperature range. This means that an invar like behavior is observed in this temperature range.