Monday  |  Heritage D  |  02:10 PM–02:30 PM

#17712, Understanding the Relationship Between Plastic Deformation and Magnetic Performance of the Soft Magnetic Alloy Hiperco

Soft magnetic materials like Hiperco exhibit highly desirable magnetic properties (high saturation, high susceptibility, low coercivity and core losses) decreasing the weight and size as well as the energy demands of a wide variety of electronics from electric motors and generators used in the aerospace industry to haptic and micro-speaker systems used in consumer electronics. However, Hiperco’s magnetic and mechanical properties are highly dependent on grain and microstructure and are significantly degraded by machining damages, suggesting that even small plastic deformations are of concern for magnetic performance. In this study we formulate a conceptual description of the relationships between compressive mechanical deformation, magnetic performance, and microstructure. We found that saturation and susceptibility were not affected by the machining stresses involved in this study, but coercivity and remanence increased to levels comparable to about 5% plastic strain. Saturation was also not affected by compressive plastic strain, but susceptibility decreased linearly with increasing plastic strain. Coercivity and remanence increased according to a power law with an exponent of approximately 0.6 with increasing plastic strain. This suggests that AC core losses will also increase at a similar rate. Dislocation mechanisms at the microstructural scale are correlated with these changes in magnetic properties with respect to plastic strain. This work provides a basis for development of models that describe Hiperco’s magnetic response to permanent deformations and helps advance our ability to predict the performance of Hiperco components.

Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.

SAND2023-10246A

Kimberley Mac Donald   Sandia National Laboratories