ON THE MAGNETIC-BEHAVIOR OF THE MA-956 SUPERALLOY

MA 956 superalloy is a ferritic stainless material which develops a fi ne, dense, and well-adhered alpha-alumina layer upon heat treatment at elevated temperatures. This unique capability makes MA 956 attractive for surgical implants. In this work, the magnetic behavior of the mat erial before and after thermal oxidation treatment required to develop the alumina layer is investigated. The thermal oxidation treatment yi elds a microstructure of elongated grains and a significant change in the texture. Despite these strong microstructural differences between the as-received and heat-treated materials, the hysteretic behavior is not greatly affected by them. MA 956 is a soft magnetic material irre spective of the material condition. The coercitive force and residual magnetization of the material are somewhat lower under heat-treated co nditions than in the as-received condition. (C) 1997 John Wiley & Sons , Inc.