Magnetostriction Hysteresis Research Articles

Narrowing of hysteresis of cubic-tetragonal martensitic transformation by weak axial stressing of ferromagnetic shape memory alloy

An influence of axial mechanical stress on the hysteresis of martensitic transformation and ordinary magnetostriction of ferromagnetic shape memory alloy has been described in the framework of a Landau-type theory of phase transitions. It has been shown that weak stress can noticeably reduce the hysteresis of martensitic transformation. Moreover, the anhysteretic deformation can be observed when the applied mechanical stress exceeds a critical stress value. The main theoretical results were compared with recent experimental data. It is argued that shape memory alloys with extremely low values of shear elastic modulus are the candidates for the experimental observation of large anhysteretic deformations.

A Model for a Thin Magnetostrictive Actuator in Nonlinear Dynamics

In this study, we propose a model for the dynamics of magnetostrictive hysteresis in a thin rod actuator when mechanically the material works in his nonlinear domain. We derive two equations that represent magnetic and mechanical dynamics equilibrium. Our model results from an application of the energy balance principle. The numerical simulations of the model with sinusoidal periodic external fieldgenerate the hysteresis curve and show the equivalent mechanic model. By using the method of multiple scales we analyze the effects of the nonlinear parameter in the system response of magnetostrictive materials. With Routh-Hurwitz theorem, the stability and bifurcation analysis are carried out. Analytical and numerical methods are used to investigate the dynamics of the materials.

Compensation of Magnetostrictive Hysteresis by Arduino: Floating Versus Fixed-Point Performances

The use of embedded computational capabilities in devices with magnetostrictive materials allows the design of objects, able to show smart features without the use of external controllers/devices. However, in the magnetostrictive devices world, the problem of getting smart performances in actuation and sensing, with a lower cost, has been faced a few times to date. In this paper, we present the compensation of the hysteresis of a magnetostrictive actuator using a low-cost Arduino platform (fixed-point mathematic). In this case, a quasi-linear actuator is obtained. The experimental performances are compared with the ones of a standard xpctarget-MATLAB environment (floating point mathematic). We found that the Arduino solution is largely acceptable, dealing with compensation errors within a few percents, and fast enough compensation times, up to sampling frequencies of kilohertz.

Comparison of magnetoelastic properties between the 〈110〉 oriented TbxDy1-xFe1.95 polycrystalline alloys with different Tb/Dy composition ratio under magnetomechanical loading

This paper presents comparison of magnetoelastic properties between the 〈110〉 oriented Tb x Dy 1-x Fe 1.95 polycrystalline alloys for x = 0.27, 0.3, 0.45 under coupled loading of magnetic field and compressive stress. The simultaneously measure are investigated for the magnetization and magnetostriction under applied magnetic field from -200 to 200 kA/m and compressive stress from 0 to 50 MPa along the rod axis at room temperature. The results show that, according to the increase of Tb concentration and compressive stress, the hysteresis, coercive force and magnetostriction hysteresis loops of Tb x Dy 1-x Fe 1.95 alloys increase rapidly and the distortion of the hysteresis loops occurs at higher compressive stress, especially Tb 0.45 Dy 0.55 Fe 1.95 alloys, while the maximum relative permeability of Tb x Dy 1-x Fe 1.95 alloys monotonously decrease. Meanwhile, the higher the Tb concentration the stronger is magnetostrictive "jump" effect. For these experimental results, the effect of compressive stress and Tb / Dy ratio on magnetoelastic properties of Tb x Dy 1-x Fe 1.95 alloys are coupling and remarkable. A tradeoff and optimization are very important for many engineering designs and applications.

The magnetostriction and its ratio to hysteresis for Tb-Dy-Ho-Fe alloys

The x(Tb0.15Ho0.85Fe2) + (1 − x)(Tb0.3Dy0.7Fe2) alloys were prepared in an arc furnace under high purity argon. The as-cast samples wrapped in Mo foil were sealed in a silica tube filled with high purity argon. The static measurement of magnetostriction (λ//, λ⊥) was made by standard strain gauge, and the magnetization M was measured by a vibrating sample magnetometer. It is found that the magnetostriction λ// of x(Tb0.15Ho0.85Fe2) + (1 − x)(Tb0.3Dy0.7Fe2) alloys decreases with increasing x and it does from 880 × 10−6 for x = 0 to 210 × 10−6 for x = 0.9 at the magnetic field of 640 kA/m. The ratio (λ///Wh) of magnetostriction to hysteresis exhibits a peak when x = 0.1, and it means that the Tb0.285Dy0.63Ho0.085Fe2 (x = 0.1) alloy possesses both large magnetostriction and small magnetostrictive hysteresis.

Study on the Giant Magnetostrictive Materials with Actuator Displacement Model Parameter Identification

Accurate identification of model parameters is to improve the giant magnetostrictive precision displacement control key, For single algorithm is difficult to achieve for giant magnetostrictive hysteresis nonlinear model parameters accurately identify problems, in this paper, the genetic algorithm and simulated annealing algorithm fusion, First, quick search ability of genetic algorithm are used to get a better community, recycle kick ability of simulated annealing algorithm to to adjust and optimize the whole group, Presented an improved genetic simulated annealing algorithm, And its application to the giant magnetostrictive actuator displacement hysteresis nonlinear model parameter identification. The algorithm combines the advantages of genetic algorithm and simulated annealing algorithm, both the faster convergence speed, and improves the precision and quality of the optimal solution.

Enhanced magnetostriction of a narrow hysteresis Tb0.26Dy0.54Ho0.20Fe2 alloy

In this work, a magnetic annealing method used to enhance the magnetostrictive property of a narrow hysteresis alloy Tb0.26Dy0.54Ho0.20Fe2 is reported. Cylindrical-rod shaped specimen with 〈110〉 crystal orientation was fabricated using zone-melting unidirectional solidification technique, followed by annealing in a transverse magnetic field of 366 kA/m. The crystal orientation and bi-phase solidified morphology can be retained after magnetic annealing. A high magnetostriction of 1.508×10−3 was obtained in the magnetically annealed specimen, which is 25.2% larger than the untreated one. Simultaneously, the magnetostriction hysteresis width is slightly enlarged from 4.45 to 6.36 kA/m, which is still much lower than that of the Ho-free Tb0.3Dy0.7Fe2 alloy. The additional anisotropy which is induced by magnetic annealing, as reflected by the magnetic hysteresis loops, is responsible for the enhancement of magnetostrictive performance.

Neural network-DFT based model for magnetostrictive hysteresis

The magnetic behavior of materials is highly sensitive to the applied stress, which is subject of this paper. In magnetostrictive materials, the relationship B(H) is strongly related to the applied mechanical stresses. The purpose of this paper is to present a simple method to identify this relation for any value of stress σ. The proposed approach is based on the knowledge of the magnetic flux density spectrum for different stress σ. So, a feed-forward neural network is trained to learn the relation between the rank of harmonics, stress and the amplitude of each harmonic. To construct the hysteresis loop for a new value of the stress σ, the neural network predicts the spectrum of the magnetic flux density B, which is transformed back to the time domain.

Magnetic properties of epoxy-bonded iron–gallium particulate composites

This paper presents the production process and the results of investigations into the microstructure and magnetic properties of epoxy-bonded iron–gallium (Galfenol) particulate composites. The manufactured composites consist of powdered Fe80Ga20 alloy particles of three different size distributions (ranging from 20 to 200 μm), bonded in an epoxy matrix with a filling factor of 0.80. The filling factor is defined as the ratio of the volume of Fe–Ga powder to the total volume of the composite’s constituents. The microstructure of the powdered alloy has been examined using x-ray diffractometry (XRD), and Mössbauer spectroscopy. Results for the measured magnetic hysteresis loop (B–H curve), static magnetostriction (λ) versus applied field and dynamic relative permeability (μr33) are presented for the alloy in the forms of bulk material, powders and composites subsequently manufactured. The highest value of magnetostriction (360 ppm) has been found in the composite with grain size in the range of 50–100 μm. On reversing the magnetic field direction, large magnetostrictive hysteresis for these samples has been observed. The value of μr33 at a given applied magnetic bias field has been found to decrease with decreasing particle size.

MAGNETOELASTIC PROPERTIES DEPENDENCE ON COMPRESSIVE STRESS IN 〈110〉 ORIENTED Tb0.45Dy0.55Fe1.95 POLYCRYSTALLINE ALLOYS WITH HIGH DRIVE LEVELS

This paper presents the magnetoelastic properties for the relative high Tb / Dy composition ratio 〈110〉 oriented Tb 0.45 Dy 0.55 Fe 1.95 polycrystalline alloys. The simultaneous measurements of the magnetization and magnetostriction are carried out as a function of applied magnetic field range of 0 to 800 kA/m and compressive stress from 0 to 60 MPa. The maximum piezomagnetic coefficient $(d^{\rm max}_{33})$ and magnetostriction hysteresis (Wh) are obtained by differential calculation from the experimental curves. According to the increase of compressive stress, an obvious magnetostriction "jump" effect is observed, and the magnetostriction with the magnetic field of 800 kA/m (λ800) and magnetostriction hysteresis monotonously increase, while the maximum piezomagnetic coefficient increases first from 0 to 10 MPa and then decreases from 10 to 60 MPa. Here, results of measuring and calculating on this material are important complement to further understand the rules of the magnetoelastic properties in high Tb/Dy composition ratio Tb 0.45 Dy 0.55 Fe 1.95 polycrystalline alloys for theoretical approaches and modern technology applications.

Influences of compressive stress on the narrow hysteresis and piezomagnetic coefficient for the <110> oriented Tb_{0.27} Dy_{0.73} Fe_{1.95} alloys at high drive levels

In this paper, the influences of compressive stress on the narrow hysteresis (magnetostriction hysteresis, W_h ) and maximum piezomagnetic coefficient ( d_{33}^{Max} ) of the <110> oriented Tb _{0.27} Dy _{0.73} Fe _{1.95} polycrystalline alloys have been investigated at high drive levels. The simultaneous measurements of magnetostriction and magnetization are carried out as a function of applied magnetic field 0 < H < 800 kA/m and compressive stress 0 to 50 MPa. The results show that the magnetostriction increases sharply in the low and/or moderate magnetic field, and than gains its saturation slowly with increase of the applied magnetic field. However, according to increase of the compressive stress, the magnetostriction decreases in the low and moderate magnetic field, while the saturation magnetostriction(λ _s ) increases. Specifically, λ _s increases from 1143 × 10 ^{ - 6} to 1778 × 10 ^{ - 6} when the compressive stress increases from 0 to 50 MPa and W_h increases from 7.90 to 27.22 kA/m at the same conditions. In addition, the characteristics of d_{33}^{Max} are reported under varied compressive stresses. It is found that the higher compressive stress the lower is d_{33}^{Max} , while at a fixed compressive stress, d_{33}^{Max} in the forward magnetostriction process is lower than that in the reversal magnetostriction process. These results presented are available for a kind of Tb-Dy-Fe alloys applications.

Derivation of Magnetostrictive Losses from Admittance Spectra

There are three types of losses for magnetostrictors, elastic loss, magnetic loss and piezomagnetic coupling loss, similar to the loss mechanism of a piezoelectric (elastic, dielectric and piezoelectric losses) that our group has established recent years. By introducing these losses factors we can characterize magnetostrictive losses using complex parameters. Here we derived the relationship of mechanical quality factors and losses factor based on admittance spectra expression we have established previously. By measuring accurately the mechanical quality factors QA for the resonance and QB for the anti-resonance in the admittance/impedance curve, we can derive these three physical losses to characterize magnetostrictive hysteresis loss.

A nonlinear magneto-thermo-elastic coupled hysteretic constitutive model for magnetostrictive alloys

This paper presents a general hysteretic constitutive law of nonlinear magneto-thermo-elastic coupling for magnetostrictive alloys. The model considered here is thermodynamically motivated and based on the Gibbs free energy function. A nonlinear part of the elastic strain arising from magnetic domain rotation induced by the pre-stress is taken into account. Furthermore, the movement of the domain walls is incorporated to describe hysteresis based on Jiles–Atherton's model. Then a set of closed and analytical expressions of the constitutive law for the magnetostrictive rods and films are obtained, and the parameters appearing in the model can be determined by those measurable experiments in mechanics and physics. Comparing this model with other existing models in this field, the quantitative results show that the relationships obtained here are more effective to describe the effects of the pre-stress or in-plane residual stress and ambient temperature on the magnetization or the magnetostriction hysteresis loops.

The stress dependence of magnetostriction hysteresis in TbDyFe [110] oriented crystal

The magnetostriction curves and minor loops of the TbDyFe [110] oriented crystal are tested under different compressive pre-stress from 0 to 120 MPa. It is observed that the magnetostriction hysteresis first increases from about 33 Oe under 0 MPa, achieves the maximum of about 70 Oe under 30 MPa, and then decreases to about 16 Oe under 120 MPa (near disappearance) with an increase in the compressive pre-stress. By the theoretical simulation, it is found that upon increasing the compressive pre-stress the dominant energy changes from magnetocrystalline anisotropy energy to magnetoelastic energy. This leads to the domain rotation mode changing from irreversibility to reversibility and consequently results in the decrease of magnetostriction hysteresis, which explains the experimental results very well.

Dependence of magnetomechanical performance of CoGaxFe2−xO4 on temperature variation

The temperature dependence of the magnetoelastic properties of the CoGaxFe2−xO4 system (for x = 0.0, 0.2, and 0.4) has been studied. It has been shown that increase in temperature resulted in reduced magnetostrictive hysteresis. For both CoGa0.2Fe1.8O4 and CoGa0.4Fe1.6O4, the measured magnetostriction amplitudes were higher at 250 K than at 150 K. It was also shown that the temperature stability of magnetostriction in CoGa0.2Fe1.8O4 is higher than that of the other compositions studiedwhich is important for sensor applications. The highest strain sensitivity was obtained for CoGa0.2Fe1.8O4 at 250 K. Results demonstrate the possibility of tailoring magnetomechanical properties of the material to suit intended applications under varying temperature conditions.

Magnetostriction and hysteresis of oriented TbDyHoFe 1.95 alloy

(Tb 0.36Dy 0.64) 1- x Ho x Fe 1.95 magnetostrictive alloys with >110< orientation were prepared by zone melting directionally solidified method. The magnetostrictive performance and hysteresis of >110< aligned polycrystalline (Tb 0.36Dy 0 64) 1- x Ho x Fe 1.95 were investigated under applied magnetic field H (0>H>4 kOe) in the temperature range from −60 to 80 °C with 0, 5 and 10 MPa pre-stress. The (Tb 0.36Dy 0.64) 1- x Ho x Fe 1.95 alloys ( x>0.3) have the character of giant magnetostriction from −60 to 80 °C. An obvious magnetostrictive “jump” effect was observed in these samples from −60 to 80 °C. The pre-stress and temperature dependence of the W h was also examined. Between the temperature range from −60 to 80 °C, the magnetostriction increased with temperature decreased, while the magnetostriction hysteresis decreased, with the pre-stress increased, but the magnetostriction and the magnetostrictive hysteresis increased.

Giant electric-field-induced magnetization in a magnetoelectric composite at high frequency

Electric-field-induced magnetization (EIM) characteristics are investigated in a small 0.68[Pb(Mg1/3Nb2/3)O3]0.32PbTiO3/Terfenol-D bilayered composite by using double coils in a wide frequency range of 10–700 kHz. The EIM behaviors are strongly dependent on driving electric field frequency, bias magnetic field, and angle θ between the bias magnetic field and polarization direction. The magnetoelectric coefficient at electromechanical resonance frequency of 185 kHz reaches up to 3.1×10−7 s/m, which is ∼60 times higher than the values at nonresonance frequency. The EIM variations with the bias magnetic field exhibit hysteresis, forming EIM hysteresis loops caused by the magnetostrictive hysteresis from Terfenol-D.

Effect of compressive stress on magnetostriction hysteresis of 〈1 1 0〉 oriented Tb 0.29Dy 0.48Ho 0.23Fe 2 crystal

The compressive pre-stress dependence of magnetostriction and magnetostriction hysteresis of 〈1 1 0〉 oriented Tb 0.29Dy 0.48Ho 0.23Fe 2 crystal has been investigated. The 〈1 1 0〉 oriented crystals in Tb 0.29Dy 0.48Ho 0.23Fe 2 alloy has been successfully prepared by zone melting unidirectional solidification. An obvious magnetostriction “jump” effect is observed with the increase of compressive pre-stress from 0 MPa to 45 MPa. The magnetostriction ( λ) at 400 mT and the magnetostriction hysteresis ( W h) monotonously increases with the increase of compressive pre-stress, and these saturate at 20 MPa compressive pre-stress. This is due to the increase in volume fraction of 90° domains rotation with the increase in compressive pre-stress, and both of these properties saturate when all of the initial domain moments distribute normal to the axis of the compressive pre-stress.

Magnetostriction and hysteresis of ⟨1 1 0⟩ oriented Tb0.29Dy0.48Ho0.23Fe2 single crystal

Magnetostriction behaviour and magnetostriction hysteresis of the single crystal alloy Tb0.29Dy0.48Ho0.23Fe2 are investigated experimentally and theoretically. The oriented ⟨1 1 0⟩ single crystals of the magnetostrictive alloy Tb0.29Dy0.48Ho0.23Fe2 are successfully prepared by the optical floating zone melting method. The single crystals are characterized by optical metallography, x-ray diffraction and x-ray Laue back-reflection measurement. The giant magnetostrictive properties are achieved in a wide operating temperature range from −60 to 80 °C. The calculated magnetostriction of the present alloy is reduced by only 6%, but the magnetostriction hysteresis (Wh) is reduced by more than 30%, compared with the traditional Terfenol-D giant magnetostrictive alloy. The magnetostriction behaviour is modelled using phenomenological theory. The rotation paths of magnetic domain moments are mathematically calculated and hence the resultant magnetostriction is obtained. The theoretical model of magnetostriction hysteresis Wh is proposed and the intrinsic factors of Wh are determined, which can well explain the pre-stress and temperature dependence of magnetostriction hysteresis.

A one-dimension coupled hysteresis model for giant magnetostrictive materials

This paper addresses the development of a one-dimension model for quantifying magnetic-elastic-thermal coupling and hysteresis inherent to giant magnetostrictive materials. Firstly, the anhysteretic law is modeled by considering the Gibbs free energy function G( σ, M, T), and thermodynamic relations are used to obtain the constitutive expressions. These expressions character the effects of coupling between stress, magnetization, and temperature in the giant magnetostrictive material but hysteresis, i.e. strain and magnetic intensity described by above the constitutive expressions are single-valued function of the magnetization. And then pinning is incorporated to describe hysteresis based on Jiles–Atherton model. The model considered in the paper is demonstrated valid by comparing the predicted results with experimental data. Moreover, the model proposed in the paper is convenient to be used in engineering applications since the parameters referred to the model have definite physical mean and can all be easily determined by experiments.