scholarly journals Production and characterization of large single crystals made of ferromagnetic shape memory alloys Ni–Mn–Ga

2010 ◽  
Vol 10 ◽  
pp. 81-86 ◽  
Author(s):  
L. Sturz ◽  
A. Drevermann ◽  
U. Hecht ◽  
E. Pagounis ◽  
M. Laufenberg
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Single Crystals ◽  
Ferromagnetic Shape Memory Alloys ◽  
Ferromagnetic Shape Memory

Hydrostatic Training and Characterization of near Stoichiometric Ni-Mn-Ga Alloy

2020 ◽  
Vol 835 ◽  
pp. 22-27
Author(s):  
Nour Mahmoud Eldabah ◽  
Saleh Mohammed Kayetbay ◽  
Mohammed A. Gepreel ◽  
Ahmed Mohamed El-Assal
Keyword(s):  
Magnetic Properties ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Stoichiometric Composition ◽  
Hydraulic Press ◽  
Ferromagnetic Shape Memory Alloys ◽  
Xrd Pattern ◽  
High Frequencies ◽  
Ferromagnetic Shape Memory

Shape memory alloys are programmed to memorize original trained shape. Ni-Mn-Ga is one of the ferromagnetic shape memory alloys. It is used as actuator, and sensor due to large output strain at high frequencies. This work presents a study on enhancing magnetic properties of thermally treated alloy by using new method of training in which alloys are exposed to different hydrostatic pressures using pressing die. Single near stoichiometric composition was produced. Elemental analysis showed homogeneity of the alloy. XRD pattern revealed Martensitic phase peaks. Transformation temperature was found to be below 100 OC. Training was applied by hydrostatic pressing die. Different training pressures were obtained using hydraulic press. After applying hydrostatic pressures starting from 2.5 bar to 10 bar, it was found that pressures up to 7.5 bar will increase the coercivity and saturation magnetization of the alloy, while pressures beyond 7.5 bar lessened these magnetic properties.

scholarly journals Structural, Thermal and Magnetic Characterization of Ni-Mn-Ga Ferromagnetic Shape Memory Alloys

2012 ◽  
Vol 1 (1) ◽  
pp. 1-7 ◽  
Author(s):  
R. Jesintha Rani ◽  
R. Senthur Pandi ◽  
S. Seenithurai ◽  
S. Vinodh Kumar ◽  
M. Muthuraman ◽  
...  
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Ferromagnetic Shape Memory Alloys ◽  
Magnetic Characterization ◽  
Ferromagnetic Shape Memory

Magnetic properties of ferromagnetic shape memory alloys Ni _{2-x} Cu _{x} MnGa

2005 ◽  
Vol 21 (3-4) ◽  
pp. 151-157 ◽  
Author(s):  
Takeshi Kanomata ◽  
Takuji Nozawa ◽  
Daisuke Kikuchi ◽  
Hironori Nishihara ◽  
Keiichi Koyama ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Ferromagnetic Shape Memory Alloys ◽  
Ferromagnetic Shape Memory

Effects of Annealing on Microstructure and Martensitic Transition of Ni-Mn-Co-In Ferromagnetic Shape Memory Alloys

2011 ◽  
Vol 674 ◽  
pp. 171-175
Author(s):  
Katarzyna Bałdys ◽  
Grzegorz Dercz ◽  
Łukasz Madej
Keyword(s):  
Electron Microscopy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Smart Materials ◽  
Martensitic Transition ◽  
Magnetic Shape Memory ◽  
Ferromagnetic Shape Memory Alloys ◽  
Initial State ◽  
X Ray ◽  
Ferromagnetic Shape Memory

The ferromagnetic shape memory alloys (FSMA) are relatively the brand new smart materials group. The most interesting issue connected with FSMA is magnetic shape memory, which gives a possibility to achieve relatively high strain (over 8%) caused by magnetic field. In this paper the effect of annealing on the microstructure and martensitic transition on Ni-Mn-Co-In ferromagnetic shape memory alloy has been studied. The alloy was prepared by melting of 99,98% pure Ni, 99,98% pure Mn, 99,98% pure Co, 99,99% pure In. The chemical composition, its homogeneity and the alloy microstructure were characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The phase composition was also studied by X-ray analysis. The transformation course and characteristic temperatures were determined by the use of differential scanning calorimetry (DSC) and magnetic balance techniques. The results show that Tc of the annealed sample was found to decrease with increasing the annealing temperature. The Ms and Af increases with increasing annealing temperatures and showed best results in 1173K. The studied alloy exhibits a martensitic transformation from a L21 austenite to a martensite phase with a 7-layer (14M) and 5-layer (10M) modulated structure. The lattice constants of the L21 (a0) structure determined by TEM and X-ray analysis in this alloy were a0=0,4866. The TEM observation exhibit that the studied alloy in initial state has bigger accumulations of 10M and 14M structures as opposed from the annealed state.

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