Iron aluminide useful as electrical resistance heating elements

Abstract

The invention relates generally to aluminum containing iron-base alloys useful as electrical resistance heating elements. The aluminum containing iron-base alloys have improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The alloy has an entirely ferritic microstructure which is free of austenite and includes, in weight %, over 4% Al, ≦1% Cr and either ≧0.05% Zr or ZrO2 stringers extending perpendicular to an exposed surface of the heating element or ≧0.1% oxide dispersoid particles. The alloy can contain 14-32% Al, ≦2% Ti, ≦2% Mo, ≦1% Zr, ≦1% C, ≦0.1% B, ≦30% oxide dispersoid and/or electrically insulating or electrically conductive covalent ceramic particles, ≦1% rare earth metal, ≦1% oxygen, ≦3% Cu, balance Fe.

Dependencies are inferred from the claim text.