scholarly journals Experimental Characterization of Geometric Aspects of the Behavior of Magnetic Shape Memory Materials and Theoretical Interpretation

2019 ◽  
Vol 4 (3) ◽  
pp. 121-126
Author(s):  
Juan Manuel Hernandez ◽  
P. Mullner ◽  
P. Linquist ◽  
J. Carreraa
Keyword(s):  
Magnetic Field ◽  
Geometric Analysis ◽  
Martensite Phase ◽  
Rotating Magnetic Field ◽  
Small Samples ◽  
Elastic Behavior ◽  
Theoretical Interpretation ◽  
Magnetic Shape Memory

Small samples of a Ni-Mn-Ga single crystal of three different geometries were subjected to bending by applying a rotating magnetic field. The magneto-mechanical behavior of the sample in cantilever was analyzed and special attention was given to elongations and curvature along the deformation process. A sequence of 3000 images was made using a high-resolution camera and the data was analyzed using a code in Matlab. Furthermore, the geometric analysis showed that, when the magnetic field is equal to cero, the sample do not recover its original shape totally and the presence of a pseudo-elastic behavior was observed. Analysis and interpretation of the data allows the presentation of some hypotheses concerning to the crystalline structure and the role of dislocations, represented by a dislocation density, in the martensite phase of these materials. These hypotheses are discussed more formally in the second part of this paper. Some experiments are proposed that would give the opportunity to a wider theoretical knowledge of MSMM.

Characterization of microstructure and nanoscale phase in Mg-15Gd-1Zn (wt.%) alloy fabricated by rotating magnetic field casting

2020 ◽  
Vol 170 ◽  
pp. 110660
Author(s):  
Zhiyu Chang ◽  
Yujuan Wu ◽  
Xiangwen Heng ◽  
Ning Su ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Rotating Magnetic Field

scholarly journals Recent Developments in Ni-Mn-Ga Foam Research

2009 ◽  
Vol 635 ◽  
pp. 119-124 ◽  
Author(s):  
Peter Müllner ◽  
Xue Xi Zhang ◽  
Yuttanant Boonyongmaneerat ◽  
Cassie Witherspoon ◽  
Markus Chmielus ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Grain Boundaries ◽  
Single Crystals ◽  
Cyclic Strain ◽  
Martensite Phase ◽  
Magnetic Shape Memory ◽  
Magnetic Shape Memory Alloys ◽  
Major Barrier

Grain boundaries hinder twin boundary motion in magnetic shape-memory alloys and suppress magnetic-field-induced deformation in randomly textured polycrystalline material. The quest for high-quality single crystals and the associated costs are a major barrier for the commercialization of magnetic shape-memory alloys. Adding porosity to polycrystalline magnetic-shape memory alloys presents solutions for (i) the elimination of grain boundaries via the separation of neighboring grains by pores, and (ii) the reduction of production cost via replacing the directional solidification crystal growth process by conventional casting. Ni-Mn-Ga foams were produced with varying pore architecture and pore fractions. Thermo-magnetic training procedures were applied to improve magnetic-field-induced strain. The cyclic strain was measured in-situ while the sample was heated and cooled through the martensitic transformation. The magnetic field-induced strain amounts to several percent in the martensite phase, decreases continuously during the transformation upon heating, and vanishes in the austenite phase. Upon cooling, cyclic strain appears below the martensite start temperature and reaches a value larger than the initial strain in the martensite phase, thereby confirming a training effect. For Ni-Mn-Ga single crystals, external constraints imposed by gripping the crystal limit lifetime and/or magnetic-field-induced deformation. These constraints are relaxed for foams.

Development of an axial rotating magnetic field multi-coil eddy current sensor for electromagnetic characterization of stratified CFRP materials

2021 ◽  
pp. 102589
Author(s):  
Ahmed Chaouki Lahrech ◽  
Mohammed Naidjate ◽  
Bachir Helifa ◽  
Abdelhalim Zaoui ◽  
Bachir Abdelhadi ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Eddy Current ◽  
Rotating Magnetic Field ◽  
Current Sensor ◽  
Eddy Current Sensor

scholarly journals On the role of rotation in the outflows of the Crab pulsar

2015 ◽  
Vol 24 (06) ◽  
pp. 1550042
Author(s):  
Gudavadze Irakli ◽  
Osmanov Zaza ◽  
Rogava Andria
Keyword(s):  
Magnetic Field ◽  
Rotation Axis ◽  
Three Dimensional ◽  
Rotating Magnetic Field ◽  
Crab Pulsar ◽  
X Ray ◽  
Field Lines ◽  
The Magnetic Field ◽  
Component Parallel

In order to study constraints imposed on kinematics of the Crab pulsar's jet, we consider motion of particles along co-rotating field lines in the magnetosphere of the Crab pulsar. It is shown that particles following the co-rotating magnetic field lines may attain velocities close to observable values. In particular, we demonstrate that if the magnetic field lines are within the light cylinder (LC), the maximum value of the velocity component parallel to the rotation axis is limited by 0.5c. This result in the context of the X-ray observations performed by Chandra X-ray Observatory seems to be quite indicative and useful to estimate the density of field lines inside the jet. Considering the three-dimensional (3D) field lines crossing the LC, we found that for explaining the force-free regime of outflows the magnetic field lines must asymptotically tend to the Archimedes spiral configuration. It is also shown that the 3D case may explain the observed jet velocity for appropriately chosen parameters of magnetic field lines.

scholarly journals Characterization of High-Temperature Superconductor Bulks for Electrical Machine Application

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1636
Author(s):  
Bruno Douine ◽  
Kevin Berger ◽  
Nickolay Ivanov
Keyword(s):  
Magnetic Field ◽  
High Temperature ◽  
Critical Current Density ◽  
High Temperature Superconductor ◽  
Small Samples ◽  
Electrical Machine ◽  
Experimental Characterization ◽  
Large Size ◽  
Magnetic Methods

High-temperature superconducting (HTS) bulks can be used in electrical applications. Experimental characterization of large-size HTS bulks is a tricky issue. The relevant parameters for their application were directly measured in this study. This paper has three main aims. Firstly, features of YBaCuO bulks are presented. Secondly, an electrical motor application is developed using magnetic field shielding and trapping. Thirdly, the HTS bulks are characterized. Several classical methods were used, which are mainly magnetic methods only available for small samples. The complete penetration magnetic field and the critical current density were found to be the main parameters relevant for applications. An innovative entire HTS bulk characterization method is presented. This characterization method is useful for end users and engineers to better implement HTS bulks.

Experimental Characterization of Efficiency Modes in a Rotating Magnetic Field Thruster

2022 ◽  
Author(s):  
Tate Gill ◽  
Christopher L. Sercel ◽  
Joshua M. Woods ◽  
Benjamin A. Jorns
Keyword(s):  
Magnetic Field ◽  
Rotating Magnetic Field ◽  
Experimental Characterization

scholarly journals Magnetic Fluids’ Heating Power Exposed to a High-Frequency Rotating Magnetic Field

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Miloš Beković ◽  
Mislav Trbušić ◽  
Mladen Trlep ◽  
Marko Jesenik ◽  
Anton Hamler
Keyword(s):  
Magnetic Field ◽  
High Frequency ◽  
Magnetic Fluids ◽  
The Body ◽  
Heating Power ◽  
Rotating Magnetic Field ◽  
Alternating Magnetic Field ◽  
Heating Effect ◽  
Rotational Magnetic Field

Magnetic fluids are superparamagnetic materials that have recently been the subject of extensive research because of their unique properties. Among them is the heating effect when exposed to an alternating magnetic field, wherein the objective is to use this property in medicine as an alternative method for the treatment of tumors in the body. The heating effect characterization for the alternating magnetic field (AMF) has been studied widely, whilst for the rotational magnetic field (RMF), no systematic study has been done yet. In this article, we present the characterization of the heating power of magnetic fluids in a high-frequency rotational magnetic field. The results show similar behavior of heating power or specific absorption rate characteristics as in AMF.

3D Energy Analysis of Magnetic-Field Induced Martensite Reorientation in Magnetic Shape Memory Alloys

2013 ◽  
Vol 738-739 ◽  
pp. 400-404 ◽  
Author(s):  
Yong Jun He ◽  
Xue Chen ◽  
Ziad Moumni
Keyword(s):  
Magnetic Field ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Energy Analysis ◽  
Three Dimensional ◽  
Rotating Magnetic Field ◽  
Magnetic Shape Memory ◽  
Ferromagnetic Shape Memory Alloys ◽  
Ferromagnetic Shape Memory ◽  
Martensite Reorientation

This paper explains the magnetic-field induced martensite reorientation in Ferromagnetic Shape Memory Alloys (FSMA) through a simple energy analysis from which the role of the martensite’s magnetic anisotropy is emphasized. In particularly, with a three-dimensional (3D) energy analysis, we study the switching between the three tetragonal martensite variants driven by a rotating magnetic field (with a constant magnitude) and a non-rotating magnetic field (with a fixed direction but varying magnitudes). Finally, a simple planar phase diagram is proposed to describe the martensite reorientation in general 3D loadings.

scholarly journals Magnetoelastic Coupling in Ni-Mn-Ga Magnetic Shape Memory Alloy

2009 ◽  
Vol 635 ◽  
pp. 125-130 ◽  
Author(s):  
Oleg Heczko
Keyword(s):  
Magnetic Field ◽  
Martensite Transformation ◽  
High Field ◽  
Indirect Method ◽  
Magnetic Energy ◽  
Opposite Sign ◽  
Magnetic Shape Memory ◽  
Magnetoelastic Coupling ◽  
Magnetic Shape Memory Alloy

The role of magnetoelastic coupling in the mechanism of magnetically induced reorientation or redistribution (MIR) of twin variants is still a matter of some controversy. To evaluate this role ordinary magnetostriction of different Ni-Mn-Ga single crystals transforming to 5M (exhibiting MIR) and NM (no MIR) martensite were measured. The magnetostriction of Ni-Mn-Ga austenite is relatively low and steeply increases when approaching to martensite transformation. This is correlated to the softening of elastic modulus. Observed high field contribution of opposite sign may be due to the dependence of higher order elastic constant on magnetic field. The magnetostriction of martensite is difficult to determine as it is masked by much stronger MIR effect and indirect method must be used. The results are discussed in the frame of magnetoelastic model for MIR and compared with magnetic energy model.

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