On the magnetic behavior of the MA 956 superalloy

MA 956 superalloy is a ferritic stainless material which develops a fine, 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 material before and after thermal oxidation treatment required to develop the alumina layer is investigated. The thermal oxidation treatment yields 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 irrespective of the material condition. The coercive force and residual magnetization of the material are somewhat lower under heat-treated conditions than in the as-received condition.