Experimental characterization and modeling of a three-variant magnetic shape memory alloy

Researchers have attempted to characterize and predict the magneto-mechanical behavior of magnetic shape memory alloys (MSMAs) for over a decade. However, all prior experimental investigations on MSMA have been performed on samples accommodating two martensite variants and generally the MSMA is only exposed to two-dimensional magneto-mechanical loading. As efforts have been underway to develop models able to predict the most general (i.e. 3D) loading conditions for MSMAs with three-varints, there is also a need for experimental data to support the calibration and validation of these models. This paper presents magneto-mechanical data from experiments where MSMA specimens, whose microstructure accommodates three martensite variants, is subjected to three-dimensional magneto-mechanical loading, along with model predictions of these experimental results. The 3D magneto-mechanical model deployed here is a modified version of the model developed by our group (LaMaster et al 2015 J. Intell. Mater. Syst. Struct. 26 663-79), and assumes that three martensite variants coexist in the material. The LaMaster et al model captures some of the general trends seen in the experimental data, but does not predict the data with a high degree of accuracy. Possible reasons for the mismatch between experimental data and model predictions are discussed.