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.

Experimental Study on the Magnetic Characteristics of Magnetic Shape Memory Alloy Materials

2013 ◽  
Vol 446-447 ◽  
pp. 230-234
Author(s):  
Tao Li ◽  
She Liang Wang ◽  
Tao Yang ◽  
Guang Yuan Weng
Keyword(s):  
Magnetic Field ◽  
Experimental Study ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Constitutive Relations ◽  
Memory Function ◽  
Magnetic Characteristics ◽  
Magnetic Shape Memory ◽  
Magnetic Shape Memory Alloy ◽  
Magnetic Induction Intensity

With shape memory function of new smart material, the magnetic control properties of magnetic shape memory alloy could be used to fabricate intelligent actuators for vibration control of structures. In order to study its magnetic properties, this text selected Ni53Mn25Ga22 as the material for the research and development of actuator drive, And two MSMA test specimens were prepared for the experimental study under the coupled action of the temperature, preload pressure and magnetic field. The results showed that the strain of MSMA induced by magnetic field decreased with the increase of the preload pressure at constant magnetic field. The deformation performance was best when the magnetic induction intensity was about 0.5T. And the constitutive relations were fitted for the actuator production to lay the foundation for later.

scholarly journals MAGNETIC FIELD EFFECTS NEAR THE LAUNCHING REGION OF ASTROPHYSICAL JETS

2010 ◽  
Vol 19 (06) ◽  
pp. 729-739 ◽  
Author(s):  
E. M. DE GOUVEIA DAL PINO ◽  
G. KOWAL ◽  
L. H. S. KADOWAKI ◽  
P. PIOVEZAN ◽  
A. LAZARIAN
Keyword(s):  
Magnetic Field ◽  
Active Galactic Nuclei ◽  
Magnetic Energy ◽  
Galactic Nuclei ◽  
Young Stellar Objects ◽  
Magnetic Field Effects ◽  
Astrophysical Jets ◽  
Stellar Objects ◽  
Fundamental Properties

One of the fundamental properties of astrophysical magnetic fields is their ability to change topology through reconnection and in doing so, to release magnetic energy, sometimes violently. In this work, we review recent results on the role of magnetic reconnection and associated heating and particle acceleration in jet/accretion disk systems, namely young stellar objects (YSOs), microquasars, and active galactic nuclei (AGNs).

Polymer Assessment for Magnetic Shape Memory Alloy Composites

2006 ◽  
Vol 977 ◽  
Author(s):  
Royale S Underhill ◽  
Gregory A Keddy ◽  
Shannon P Farrell
Keyword(s):  
Shape Memory ◽  
Polymer Composite ◽  
Magnetic Energy ◽  
Mechanical Energy ◽  
Particle Dispersion ◽  
Magnetic Shape Memory ◽  
Power Sources ◽  
Magnetic Shape Memory Alloy ◽  
Entire Matrix ◽  
Nickel Manganese

AbstractOur surrounding environment is teeming with useful energy, waiting to be harnessed (i.e., solar, wind, tidal, etc.). If this energy can be exploited at the point where it is required, then the need to carry additional power sources can be reduced. In recent years, magnetic shape memory alloys (MSMA) have demonstrated an ability to convert mechanical energy to magnetic energy. Such conversions have lead to the investigation of these alloys for energy harvesting applications.There are a number of issues to address when forming a MSMA/polymer composite. The polymer must be stiff enough to transmit the induced strain through the entire matrix, yet soft enough not to exceed the MSMA blocking stress. Also, the polymer must not dampen any force applied before it can be transmitted to the MSMA particles.Ten polymers have been investigated for MSMA/polymer composites. The work presented here will describe progress in nickel-manganese-gallium (Ni-Mn-Ga)/polymer composite fabrication and characterization. Special attention will be given to polymer selection, optimizing particle dispersion and MSMA/polymer interfacial interactions.

Hysteretic Nonlinear Model of Magnetic Shape Memory Alloy

2011 ◽  
Vol 121-126 ◽  
pp. 191-195
Author(s):  
Zhi Wen Zhu ◽  
Liang Gao ◽  
Jia Xu
Keyword(s):  
Magnetic Field ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Field Intensity ◽  
Magnetic Field Intensity ◽  
Partial Least Square ◽  
Least Square ◽  
Hysteresis Phenomenon ◽  
Magnetic Shape Memory ◽  
Magnetic Shape Memory Alloy

In this paper, a kind of Magnetic Shape Memory Alloy (MSMA) model based on hysteretic nonlinear theory was developed. Von del Pol nonlinear difference item was introduced to interpret the hysteresis phenomenon of strain-magnetic field intensity (MFI) curve of MSMA. The final relationship among strain, stress and magnetic field intensity was obtained in partial least-square regression method to describe the variation of strain-MFI curve with stress. The result of forecast test shows that the model can describe the characteristics of MSMA in different stress well. The new MSMA model is easy to be analyzed in theory, which is helpful to application of MSMA in engineering fields.

A New Type Electrohydraulic Servo Valve Based on Magnetic Shape Memory Alloy

2013 ◽  
Vol 873 ◽  
pp. 91-94
Author(s):  
Fu Quan Tu ◽  
Yang Mao ◽  
Ren Bo Xu
Keyword(s):  
Magnetic Field ◽  
Shape Memory ◽  
Functional Materials ◽  
Shape Variation ◽  
Magnetic Shape Memory ◽  
Servo Valve ◽  
Magnetic Shape Memory Alloy ◽  
New Type ◽  
Variation Mechanism ◽  
The Relationship

In this paper, the magnetically controlled characteristic and shape variation mechanism magnetic shape memory alloys (MSMA) sample are studied through the servo valve actuator based on the MSMA. The MSMA is a new type of functional materials, which has huge driving force and large controllability displacement. The kind of actuator is designed by differential mode of MSMA, employing bias coils to generate biasing magnetic field and applying field coils to provide magnetic field which is controllable. The relationship between displacement of the new actuator and time is got by numerical simulation using Maxwell software. Finally, motivated by the simulation results, the rationality of structural design of the new type of actuator is validated.

Shape Memory Effect in Fe-Pd Magnetic Shape Memory Alloy Thin Films

2010 ◽  
Vol 654-656 ◽  
pp. 2107-2110
Author(s):  
Jun Hyun Han ◽  
Tae Ahn ◽  
Hyun Kim ◽  
Kwang Koo Jee
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Stress Change ◽  
Composition Gradient ◽  
Cantilever Beams ◽  
Magnetic Shape Memory ◽  
Magnetic Shape Memory Alloy

The shape memory effect (SME) and magnetic shape memory effect (MSME) Fe-Pd thin film are using the film curvature method. The corresponding residual stress change due to theSME and MSME in Fe-Pd film is measuredduring thermal cycling and magnetic field changing. AFe-Pd thin film with a lateral composition gradient is deposited onto micromachined x7 cantilever beam arraysubstrate,such that each of the cantilever beams is coated with a film of different composition.There is abrupt stress change in only .1 at % Pd as the temperature of the film is cycled, and the corresponding stress change was measured as 0.16 GPa. The film with .4 at % Pd showsthe abrupt stress change at 0.7 Tesla, which means that the composition has the MSME.

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