scholarly journals Temperature contour maps at the strain-induced martensitic transition of a Cu–Zn–Al shape-memory single crystal

2011 ◽  
Vol 98 (1) ◽  
pp. 011902 ◽  
Author(s):  
Eduard Vives ◽  
Susan Burrows ◽  
Rachel S. Edwards ◽  
Steve Dixon ◽  
Lluís Mañosa ◽  
...  
Keyword(s):  
Single Crystal ◽  
Shape Memory ◽  
Martensitic Transition ◽  
Contour Maps ◽  
Temperature Contour

THE USE OF SHAPE-MEMORY ALLOYS FOR MECHANICAL REFRIGERATION

2009 ◽  
Vol 02 (02) ◽  
pp. 73-78 ◽  
Author(s):  
LLUÍS MAÑOSA ◽  
ANTONI PLANES ◽  
EDUARD VIVES ◽  
ERELL BONNOT ◽  
RICARDO ROMERO
Keyword(s):  
Shape Memory Alloys ◽  
Single Crystal ◽  
Shape Memory ◽  
Large Temperature ◽  
Martensitic Transition ◽  
Stress Strain ◽  
Temperature Changes ◽  
Entropy Changes ◽  
Elastocaloric Effect ◽  
Different Temperatures

This letter reports on stress–strain experiments on a Cu – Zn – Al single crystal performed using a purpose-built tensile device which enables the load applied to the specimen to be controlled while elongation is continuously monitored. From the measured isothermal tensile curves, the stress-induced entropy changes are obtained at different temperatures. These data quantify the elastocaloric effect associated with the martensitic transition in shape-memory alloys. The large temperature changes estimated for this effect, suggest the possibility of using shape-memory alloys as mechanical refrigerators.

Cu-AI based single crystal shape memory actuators and drives

2003 ◽  
Vol 112 ◽  
pp. 1181-1184 ◽  
Author(s):  
I. Vahhi ◽  
S. Pulnev ◽  
A. Priadko
Keyword(s):  
Single Crystal ◽  
Shape Memory ◽  
Crystal Shape ◽  
Shape Memory Actuators

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 Martensitic transition and magnetoresistance in a Cu-Al-Mn shape-memory alloy: Influence of ageing

2002 ◽  
Vol 66 (5) ◽  
Author(s):  
Jordi Marcos ◽  
Antoni Planes ◽  
Lluís Mañosa ◽  
Amílcar Labarta ◽  
Bart Jan Hattink
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Martensitic Transition

A phenomenological model for thermally-induced hysteresis in polycrystalline shape memory alloys with internal loops

2021 ◽  
pp. 1045389X2110482
Author(s):  
Yuxiang Han ◽  
Haoyuan Du ◽  
Linxiang Wang ◽  
Roderick Melnik
Keyword(s):  
Shape Memory Alloys ◽  
Single Crystal ◽  
Shape Memory ◽  
Phenomenological Model ◽  
Landau Theory ◽  
Thermally Induced ◽  
First Order ◽  
Proposed Model ◽  
Crystal Model ◽  
Hysteretic Response

In the current study, a 1-D phenomenological model is constructed to capture the temperature-induced hysteretic response in polycrystalline shape memory alloys (SMAs). The martensitic and austenitic transformations are regarded as the first-order transitions. A differential single-crystal model is formulated on the basis of Landau theory. It is assumed that the transformation temperatures follow the normal distribution among the grains due to the anisotropic stress field developed in the material. The polycrystalline hysteretic response is expressed as the integration of single-crystal responses. Besides, the prediction strategy for incomplete transitions is presented, and the first-order reversal curves are obtained via density reassignment. The proposed model is numerically implemented for validation. Comparisons between the modeling results and the experimental ones demonstrate the capability of the proposed model in addressing the hysteresis in thermally-induced phase transformations.

scholarly journals Giant two-way shape memory effect in high-temperature Ni–Mn–Ga single crystal

2010 ◽  
Vol 10 ◽  
pp. 94-98 ◽  
Author(s):  
V.A. Chernenko ◽  
E. Villa ◽  
S. Besseghini ◽  
J.M. Barandiaran
Keyword(s):  
High Temperature ◽  
Single Crystal ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect
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