scholarly journals Investigation of the bainitic reaction in a CuAlNiMnFe shape memory alloy

2013 ◽  
Vol 49 (1) ◽  
pp. 43-47 ◽  
Author(s):  
M. Benke ◽  
V. Mertinger ◽  
P. Pekker
Keyword(s):  
Heat Flux ◽  
Martensitic Transformation ◽  
Shape Memory ◽  
Functional Materials ◽  
Martensitic Transformations ◽  
Bainitic Transformation ◽  
Thermoelastic Martensitic Transformation ◽  
Thermoelastic Martensitic Transformations ◽  
Thermoelastic Transformation ◽  
Heat Flux Dsc

Despite their favorable properties, brittle nature of the CuAlNi shape memory alloys limits their suitability. To increase their ductility, Mn and Fe were added to the base CuAlNi alloy. To reveal the applicability of the developed CuAlNiMn and CuAlNiMnFe alloys as functional materials, the effect of ageing on the thermoelastic martensitic transformation was investigated. During the first heating of the aged samples the thermoelastic ?? ? ? transformation occurred, which was followed by a bainitic transformation. This transformation inhibited the further thermoelastic martensitic transformations. The present paper covers heat flux DSC, SEM, and TEM investigations of the bainitic transformation. A feasible mechanism of the bainitic transformation in these alloys is suggested based on the results of the examinations.

Shape memory effect due to magnetic field-induced thermoelastic martensitic transformation in polycrystalline Ni–Mn–Fe–Ga alloy

2001 ◽  
Vol 291 (2-3) ◽  
pp. 175-183 ◽  
Author(s):  
A.A. Cherechukin ◽  
I.E. Dikshtein ◽  
D.I. Ermakov ◽  
A.V. Glebov ◽  
V.V. Koledov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Martensitic Transformation ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Thermoelastic Martensitic Transformation

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.

Analysis on the Martensitic Transformation in the Ti-xNb Alloys Using a Phenomenological Theory

2007 ◽  
Vol 124-126 ◽  
pp. 1669-1672 ◽  
Author(s):  
Hi Won Jeong ◽  
Seung Eon Kim ◽  
Chang Yong Jo ◽  
Yong Tae Lee ◽  
Joong Kuen Park
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Martensitic Transformation ◽  
Shape Memory ◽  
Titanium Alloys ◽  
Martensitic Transformations ◽  
Phenomenological Theory ◽  
Transition Elements ◽  
Low Elastic Modulus ◽  
Diffraction Peaks

The titanium alloys containing the Nb transition elements have been investigated as the Ni-free shape memory and the biomedical alloys with a low elastic modulus. The mechanical properties of the alloys depended upon the meta-stable phases like the α`, α``, ω. To study the martensitic transformations from the β to α`` or α` the Ti-xNb (x=0 to 40 wt%) alloys were melted into the button type ingots using a VAR, and followed by the water-quenching after the soaking at 1000oC for 2hrs. The crystallography of the martensitic phases in the water-quenched alloys was analyzed using a XRD. The diffraction peaks of the orthorhombic martensites were identified by the crystallographic relationship with the bcc matrix. The lattice parameters of the orthorhombic martensites were varied continuously with the contents of the Nb elements. The martensitic transformations of the alloys were studied using the phenomenological theory of Bowles and Mackenzie.

High-temperature shape memory effect and the B2-L10 thermoelastic martensitic transformation in Ni-Mn intermetallics

2013 ◽  
Vol 58 (6) ◽  
pp. 878-887 ◽  
Author(s):  
V. G. Pushin ◽  
N. N. Kuranova ◽  
E. B. Marchenkova ◽  
E. S. Belosludtseva ◽  
V. A. Kazantsev ◽  
...  
Keyword(s):  
High Temperature ◽  
Martensitic Transformation ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Thermoelastic Martensitic Transformation

Investigation of Ageing Phenomena in CuAlNi Based Shape Memory Alloys

2007 ◽  
Vol 537-538 ◽  
pp. 129-136 ◽  
Author(s):  
Marton Benke ◽  
Valéria Mertinger ◽  
E. Nagy ◽  
Jan Van Humbeeck
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Ternary Alloy ◽  
Room Temperature ◽  
Beta Phase ◽  
Heat Treatments ◽  
Thermoelastic Martensitic Transformation ◽  
Transformation Temperatures ◽  
Exothermic Process

The ageing phenomena and its effect on the thermoelastic martensitic transformation was investigated in three Cu-base SMAs. The transformation temperatures shifted to higher temperatures due to aging in the beta-phase. To increase the alloy’s ductility, a definite amount of Mn (4 wt%) and Fe (2 wt%) were added to the ternary alloy. The thermoelastic martensitic transformation was found in the not-aged samples of the CuAlNiMn and CuAlNiMnFe alloys. This transformation was destroyed due to ageing heat treatments by a fairly unknown exothermic process. The thermoelastic martensitic transformation appeared again in the aged CuAlNiMn and CuAlNiMnFe samples after keeping them on room temperature for a few months. This phenomena was investigated by DSC, SEM, TEM, and XRD.

Precipitates Formation in Ti-Ni Equiatomic Alloys due to Annealing Heat Treatment

2010 ◽  
Vol 643 ◽  
pp. 49-54 ◽  
Author(s):  
Carlos Augusto Nascimento Oliveira ◽  
Euclides Apolinário Cabral De Pina ◽  
Cezar Henrique Gonzalez ◽  
Carlos José de Araújo ◽  
U.S.L. Filho ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Martensitic Transformation ◽  
Shape Memory ◽  
Martensitic Transformations ◽  
Smart Material ◽  
X Ray Diffraction ◽  
X Ray ◽  
Metallurgical Investigation ◽  
Annealing Heat Treatment ◽  
Annealing Heat

The use of smart material such as Ti-Ni in actuators application requires an intense mechanical and metallurgical investigation to understand its behavior. This paper studies martensitic transformation using DSC and X-ray diffraction techniques to compare shape memory parameters in Ti-50.2%Ni (A1) and equiatomic Ti-50.0%Ni (A2) Alloys. The as as-received samples were submitted to annealing at 400°C and 500°C for 24 hours then quenched in at 25°C. The influence of heat treatment on martensitic transformations temperatures and the appearance of R-phase were analyzed using DSC and X-ray diffraction.

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