Incubation Time of Occurrence of Magnetic Field-Induced Martensitic Transformation in an Fe–24.8Ni–3.7Mn (at%) Alloy

Abstract

Incubation time of occurrence of magnetic field-induced martensitic transformation has been investigated in an Fe–24.8Ni–3.7Mn (at%) alloy. Under a static magnetic field of 9 T, the alloy shows an isothermal martensitic transformation with a nose at 140 K in the time-temperature-transformation phase diagram. Under a pulsed magnetic field at 77 K, however, it exhibits an athermal martensitic transformation (a burst-type one). When the maximum field of 26.8 T is applied, the martensitic transformation starts in the field applying process at 16.54 T, but when the maximum field of 14.10 T is applied, the martensitic transformation starts in the field removing process. The time delay from the maximum field is in the order of several tens of microsecond and is probably related to the requirement of time to prepare for the nucleation of martensitic transformation.