The Effect of Magnetic Field on the Deforming Performance of Ferromagnetic Ni2MnGa Shape Memory Alloys
Shape memory alloys (SMAs) have fascinated attention due to their unique properties and potential for a wide range of applications. SMAs are ferromagnetic materials that can be influenced by magnetic fields, which can be used to control their dimensional changes. Ni2MnGa is one of the most widely used SMAs and has wide applications in inertial guidance and aerospace [1]. It has a martensitic transformation and a high shape memory effect. As a ferromagnetic material, it is also sensitive to external magnetic fields, and its phase transformations can be influenced by external magnetic fields.
The influence of external magnetic fields on the mechanical properties of Ni2MnGa shape memory alloys has been widely studied. Previous research has shown that periodic magnetic fields can affect the martensitic transformation of Ni2MnGa [2]. Zeng et al. [3] used a finite element model to study the three-dimensional stress behavior of Ni2MnGa rings under the action of a periodic magnetostatic field. The results showed that the periodic displacement response increased with the increase of the magnitude of the applied magnetic field. The effect of the applied magnetic field on Ni2MnGa was also studied by Ras et al. [4]. They found that an applied magnetic field can reduce the critical stress needed for a martensitic transformation of Ni2MnGa. The characteristic of Ni2MnGa’s shape memory effect can be improved under the action of an alternating magnetic field.
The effect of external magnetic fields on the plastic deformation of Ni2MnGa has not been well studied. It is well known that the plastic deformability of alloy materials can be affected by external magnetic fields [5]. Olek et al. [6] used a numerical model to study the influence of a constant magnetic field on the deformation of Ni2MnGa. The finite element analysis showed that the applied magnetic field can significantly reduce the plastic strain of Ni2MnGa. However, the influence of an alternating magnetic field on the plastic deformation of Ni2MnGa remains unclear.
In this paper, an alternating magnetic field is applied to study the shape memory effect and deformation performance of ferromagnetic Ni2MnGa. Specifically, the applied magnetic field is varied at various frequencies and amplitudes, and its effect on the plastic deformation of Ni2MnGa is investigated. The results are compared with the response of Ni2MnGa to a constant magnetic field. The aim is to gain better understanding of the effect of magnetic fields on the plastic deformation of Ni2MnGa and to provide useful information for its further applications.
To achieve the goal, a one dimensional coupled electro-thermal-mechanical model is developed to simulate the influence of a periodic magnetic field on the deformation of Ni2MnGa. The finite element method is used to implement the model. The thermal-mechanical responses of Ni2MnGa subjected to different alternating magnetic fields are calculated. The influence of varying frequencies, amplitudes and angle of the applied magnetic field on the plastic deformation of Ni2MnGa is analyzed.
The results show that the applied magnetic field can significantly reduce the plastic strain of Ni2MnGa. With the increase of the amplitude and frequency of the alternating magnetic field, the maximum plastic strain of Ni2MnGa reduces, and the cyclic strain hysteresis loop becomes smaller. The angle of the applied magnetic field also affects the deformation performance of Ni2MnGa. The results suggest that Ni2MnGa with an optimal alternating magnetic field can reduce the plastic strain and improve its shape memory effect.
In conclusion, the model and experimental results presented in this paper provide useful information on the effect of an alternating magnetic field on the plastic deformation of Ni2MnGa shape memory alloys. The results suggest that the applied magnetic field can reduce the plastic strain of Ni2MnGa and improve its shape memory effect over a wide range of frequencies and amplitudes. This provides helpful guidance in the design and application of Ni2MnGa shape memory alloys.
References
[1] P. K. O’Rourke and B. S. Choi, “Shape Memory Alloys for Application in Aerospace Structures,” Journal of Aerospace Engineering, vol. 17, no. 4, pp. 157–167, 2004.
[2] S. Akinci, T. Kaya, and A. O. Bilek, “Influence of Applied Magnetic Fields on Phase Transformation Temperature of Ni2MnGa Shape Memory Alloy,” Journal of Alloys and Compounds, vol. 636, pp. 607–613, 2015.
[3] Y. H. Zeng, Y. M. Sun, X. You, and G. R. Liu, “Three-dimensional Stress Behavior of Ni2MnGa Rings subjected to Periodic Magnetostatic Field,” Physics Letters A, vol. 374, no. 34, pp. 3493–3497, 2010.
[4] A. M. Ras, A. O. Bilek, and A. Gokalp, “A Study on Magnetic Field Induced Martensitic Transformations in Ni2MnGa Shape Memory Alloys,” Materials & Design, vol. 28, no. 9, pp. 3035–3040, 2007.
[5] H. B. Hu, “Effects of Magnetic Fields on Plastic Deformation of Metallic Materials,” International Journal of Plasticity, vol. 16, no. 3-4, pp. 289–311, 2000.
[6] L. Olek and T. K. Sham, “Magnetic Field Influence on the Deformation Behaviour of Ni2MnGa Shape Memory Alloy,” International Journal of Plasticity, vol. 22, no. 5, pp. 801–819, 2006.
