The hysteresis cycle modification in thermoelastic martensitic transformation of shape memory alloys

1997 ◽  
Vol 36 (11) ◽  
pp. 1273-1278 ◽  
Author(s):  
G. Airoldi ◽  
A. Corsi ◽  
G. Riva
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Hysteresis Cycle ◽  
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.

Atomic Order and Martensitic Transformation in Cu-Al-Be Shape Memory Alloys

1995 ◽  
Vol 05 (C8) ◽  
pp. C8-973-C8-978
Author(s):  
M. Jurado ◽  
Ll. Mañosa ◽  
A. González-Comas ◽  
C. Stassis ◽  
A. Planes
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Atomic Order

scholarly journals Effect of Crystallographic Orientation and Grain Boundaries on Martensitic Transformation and Superelastic Response of Oligocrystalline Fe–Mn–Al–Ni Shape Memory Alloys

2021 ◽  
Author(s):  
A. Bauer ◽  
M. Vollmer ◽  
T. Niendorf
Keyword(s):  
Martensitic Transformation ◽  
Grain Boundary ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Grain Boundaries ◽  
Tensile Tests ◽  
Image Correlation ◽  
Stress Concentrations ◽  
Grain Orientations ◽  
High Degree

AbstractIn situ tensile tests employing digital image correlation were conducted to study the martensitic transformation of oligocrystalline Fe–Mn–Al–Ni shape memory alloys in depth. The influence of different grain orientations, i.e., near-〈001〉 and near-〈101〉, as well as the influence of different grain boundary misorientations are in focus of the present work. The results reveal that the reversibility of the martensite strongly depends on the type of martensitic evolving, i.e., twinned or detwinned. Furthermore, it is shown that grain boundaries lead to stress concentrations and, thus, to formation of unfavored martensite variants. Moreover, some martensite plates seem to penetrate the grain boundaries resulting in a high degree of irreversibility in this area. However, after a stable microstructural configuration is established in direct vicinity of the grain boundary, the transformation begins inside the neighboring grains eventually leading to a sequential transformation of all grains involved.

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