On the effect of cobalt doping on thermoelastic martensitic transformations in ferromagnetic Heusler Ni50 − x Co x Mn29Ga21 magnetically controlled shape memory alloys

2013 ◽  
Vol 39 (8) ◽  
pp. 737-740 ◽  
Author(s):  
V. G. Pushin ◽  
A. V. Korolev ◽  
N. I. Kourov ◽  
N. N. Kuranova ◽  
E. B. Marchenkova ◽  
...  
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Martensitic Transformations ◽  
Cobalt Doping ◽  
Thermoelastic Martensitic Transformations

Thermodynamic Analysis of Thermoelastic Martensitic Transformations

2004 ◽  
Vol 449-452 ◽  
pp. 1325-0 ◽  
Author(s):  
Yinong Liu
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Experimental Determination ◽  
Thermodynamic Parameters ◽  
Thermodynamic Analysis ◽  
Martensitic Transformations ◽  
Thermoelastic Martensitic Transformations ◽  
The Past ◽  
Concise Overview

This paper is concerned with the application of fundamental thermodynamic theories in the analysis of thermoelastic martensitic transformations in shape memory alloys, with a particular reference to polycrystalline NiTi. The discussion is delivered in two parts. The first part presents a concise overview of the fundamental theories of thermodynamics of thermoelastic martensitic transformations established in the past 30 years. The second part focuses on the principles governing the application of the theories, interpretation of the thermodynamic parameters defined in the theories, experimental determination of the parameters, and some common misperceptions and unjustified assumptions in practice concerning these parameters.

scholarly journals Effect of Hydrostatic Pressures on Thermoelastic Martensitic Transformations in Aged Ti–Ni and Ausaged Fe–Ni–Co–Ti Shape Memory Alloys

1992 ◽  
Vol 33 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Tomoyuki Kakeshita ◽  
Ken’ichi Shimizu ◽  
Sei Nakamichi ◽  
Ritsu Tanaka ◽  
Shoichi Endo ◽  
...  
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Martensitic Transformations ◽  
Thermoelastic Martensitic Transformations

Thermal arrest analysis of thermoelastic martensitic transformations in shape memory alloys

2011 ◽  
Vol 26 (10) ◽  
pp. 1243-1252 ◽  
Author(s):  
Qinglin Meng ◽  
Hong Yang ◽  
Yinong Liu ◽  
Tae-hyun Nam ◽  
F. Chen
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Martensitic Transformations ◽  
Thermal Arrest ◽  
Thermoelastic Martensitic Transformations ◽  
Image Position

Abstract

On the effect of aging on martensitic transformations in Ni-rich NiTi shape memory alloys

2005 ◽  
Vol 14 (5) ◽  
pp. S186-S191 ◽  
Author(s):  
Gunther Eggeler ◽  
Jafar Khalil-Allafi ◽  
Susanne Gollerthan ◽  
Christoph Somsen ◽  
Wolfgang Schmahl ◽  
...  
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Martensitic Transformations ◽  
Niti Shape Memory Alloys

Powder Metallurgical Processes for NiTi Shape Memory Alloys

2010 ◽  
Vol 636-637 ◽  
pp. 928-933
Author(s):  
Filipe Neves ◽  
Francisco Manuel Braz Fernandes ◽  
Isabel M. Martins ◽  
Jose Brito Correia ◽  
Manuela Oliveira ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Martensitic Transformations ◽  
Reactive Extrusion ◽  
Powder Mixtures ◽  
Heat Treated ◽  
Niti Shape Memory Alloys ◽  
Metallurgical Processes ◽  
Niti Matrix

Two promising powder metallurgy (PM) processes were used for the fabrication of NiTi shape memory alloys (SMA): Mechanically Activated Reactive FOrging Synthesis (MARFOS) and Mechanically Activated Reactive Extrusion Synthesis (MARES). In these two processes, equimolar powder mixtures of elemental Ni and Ti are first mechanically activated and then forged/extruded at relatively low temperature. Afterwards, heat treatments are used to promote homogenization and to adjust the composition of the NiTi matrix. When MARFOS and MARES processes are compared some differences have been observed but only in relation to the extent of phase transformation and to the degree of densification. The crystallite size was less than 100 nm for all the phases which indicates nanostructured materials and multi-step martensitic transformations could be observed in heat treated materials.

Ab initio modeling of martensitic transformations (MT) in magnetic shape memory alloys

2007 ◽  
Vol 310 (2) ◽  
pp. 2761-2763 ◽  
Author(s):  
P. Entel ◽  
M.E. Gruner ◽  
W.A. Adeagbo ◽  
C.-J. Eklund ◽  
A.T. Zayak ◽  
...  
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Ab Initio ◽  
Martensitic Transformations ◽  
Magnetic Shape Memory ◽  
Magnetic Shape Memory Alloys ◽  
Ab Initio Modeling

Martensitic Transformations and Functional Stability in Ultra-Fine Grained NiTi Shape Memory Alloys

2008 ◽  
Vol 584-586 ◽  
pp. 852-857 ◽  
Author(s):  
Juri Burow ◽  
Egor Prokofiev ◽  
Christoph Somsen ◽  
Jan Frenzel ◽  
Ruslan Valiev ◽  
...  
Keyword(s):  
Grain Size ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Thermomechanical Processing ◽  
High Pressure Torsion ◽  
Martensitic Transformations ◽  
Coarse Grained ◽  
Functional Stability ◽  
Fine Grained ◽  
Niti Shape Memory Alloys

Martensitic transformations in NiTi shape memory alloys (SMAs) strongly depend on the microstructure. In the present work, we investigate how martensitic transformations are affected by various types of ultra-fine grained (UFG) microstructures resulting from various processing routes. NiTi SMAs with UFG microstructures were obtained by equal channel angular pressing, high pressure torsion, wire drawing and subsequent annealing treatments. The resulting material states were characterized by transmission electron microscopy and differential scanning calorimetry (DSC). The three thermomechanical processing routes yield microstructures which significantly differ in terms of grain size and related DSC chart features. While the initial coarse grained material shows a well defined one-step martensitic transformation on cooling, two-step transformations were found for all UFG material states. The functional stability of the various UFG microstructures was evaluated by thermal cycling. It was found that UFG NiTi alloys show a significantly higher stability. In the present work, we also provide preliminary results on the effect of grain size on the undercooling required to transform the material into B19’ and on the related heat of transformation.

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