Testing system for ferromagnetic shape memory microactuators

Y. Ganor, D. Shilo, J. Messier, T. W. Shield, R. D. James

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

Ferromagnetic shape memory alloys are a class of smart materials that exhibit a unique combination of large strains and fast response when exposed to magnetic field. Accordingly, these materials have significant potential in motion generation applications such as microactuators and sensors. This article presents a novel experimental system that measures the dynamic magnetomechanical behavior of microscale ferromagnetic shape memory specimens. The system is comprised of an alternating magnetic field generator (AMFG) and a mechanical loading and sensing system. The AMFG generates a dynamic magnetic field that periodically alternates between two orthogonal directions to facilitate martensitic variant switching and to remotely achieve a full magnetic actuation cycle, without the need of mechanical resetting mechanisms. Moreover, the AMFG is designed to produce a magnetic field that inhibits 180° magnetization domain switching, which causes energy loss without strain generation. The mechanical loading and sensing system maintains a constant mechanical load on the measured specimen by means of a cantilever beam, while the displacement is optically monitored with a resolution of approximately 0.1 μm. Preliminary measurements using Ni2 MnGa single crystal specimens, with a cross section of 100×100 μ m2, verified their large actuation strains and established their potential to become a material of great importance in microactuation technology.

Original languageEnglish (US)
Article number073907
JournalReview of Scientific Instruments
Volume78
Issue number7
DOIs
StatePublished - 2007

Bibliographical note

Funding Information:
The authors acknowledge the support of ONR N000140610530 (Galfenol MURI), AFOSR STTR FA9550-05-C-0035, and NSF-NIRT DMS-0304326.

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