Soft magnetic structural alloys for elevated-temperature applications

Metallurgical efforts to develop a soft magnetic material suitable for application in the rotor of a generator or motor in advanced aerospace electric systems are reviewed. Commercial materials which have been considered include AISI 4340 steel, H-11 steel, Nivco alloy, and 15- and 18-percent Ni maraging steels. Developments described have led to several new materials with combination of good mechanical and magnetic properties at elevated temperature. Such materials include an improved maraging steel a precipitation hardenable cobalt-base alloy, a carbide strengthened Co-W alloy, dispersion-strengthened soft magnetic alloys, and unidirectionally solidified Co-Nb-Fe eutectic alloys.