Estimation of entropy change at the first order martensitic transition in Ni–Mn–X based ferromagnetic shape memory alloys

2014 ◽  
Vol 448 ◽  
pp. 327-329 ◽  
Author(s):  
Rahul Das ◽  
A. Perumal ◽  
A. Srinivasan
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Entropy Change ◽  
Martensitic Transition ◽  
Ferromagnetic Shape Memory Alloys ◽  
First Order ◽  
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.

scholarly journals Study of the martensitic transition in Ni-Mn-Sn-Ti ferromagnetic shape memory alloys

2018 ◽  
Vol 23 (2) ◽  
Author(s):  
Federico Guillermo Bonifacich ◽  
Osvaldo Agustín Lambri ◽  
José Ignacio Pérez-Landazábal ◽  
Vicente Recarte ◽  
Damián Gargicevich ◽  
...  
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Martensitic Transition ◽  
Ferromagnetic Shape Memory Alloys ◽  
Ferromagnetic Shape Memory

scholarly journals Entropy Change Caused by Martensitic Transformations of Ferromagnetic Shape Memory Alloys

Metals ◽  
2017 ◽  
Vol 7 (11) ◽  
pp. 509
Author(s):  
Victor L’vov ◽  
Eduard Cesari ◽  
Anna Kosogor ◽  
Joan Torrens-Serra ◽  
Vicente Recarte ◽  
...  
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Martensitic Transformations ◽  
Entropy Change ◽  
Ferromagnetic Shape Memory Alloys ◽  
Ferromagnetic Shape Memory
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