Measurements are performed to characterize the nonlinear and hysteretic magnetomechanical coupling of iron-gallium (Galfenol) alloys. Magnetization of production and research grade Galfenol is measured under applied stress at constant field, applied field at constant stress, and alternately applied field and stress. A high degree of reversibility in the magnetomechanical coupling is observed by comparing a series of applied field at constant stress experiments with a single applied stress at constant field experiment. Accommodation is not evident and magnetic hysteresis for both applied field and stress is shown to be coupled. A stress, field, and orientation dependent hysteron is developed from continuum thermodynamics which employs a unified hysteresis mechanism for both applied stress and field. The hysteron has an instantaneous loss mechanism similar to Coulomb-friction or Preisach-type models and is shown to satisfy the second law of thermodynamics. Stochastic homogenization is employed to account for the smoothing effect that material inhomogeneities have on the magnetization.

Date Published: 31 March 2009
PDF: 13 pages
Proc. SPIE 7289, Behavior and Mechanics of Multifunctional Materials and Composites 2009, 72891X (31 March 2009); doi: 10.1117/12.815826

Published in SPIE Proceedings Vol. 7289:
Behavior and Mechanics of Multifunctional Materials and Composites 2009
Zoubeida Ounaies; Jiangyu Li, Editor(s)