scholarly journals On the Full-Field Deformation of Single Crystal CuAlNi Shape Memory Alloys—Stress-Induced β1 → γ'1 Martensitic Transformation

1997 ◽  
Vol 07 (C5) ◽  
pp. C5-555-C5-560 ◽  
Author(s):  
X. Y. Zhang ◽  
T. T. Xu ◽  
Q. P. Sun ◽  
P. Tong
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory Alloys ◽  
Single Crystal ◽  
Shape Memory ◽  
Full Field

Martensitic Transformation in Submicron Cu-Al-Ni Pillar

2013 ◽  
Vol 1581 ◽  
Author(s):  
Lifeng Liu ◽  
Yumei Zhou ◽  
Lan Lv
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory Alloys ◽  
Single Crystal ◽  
Shape Memory ◽  
Sample Size ◽  
Small Scale ◽  
Bulk Materials ◽  
Stress Curve ◽  
Strain Stress

ABSTRACTThe transformation plateau on the strain-stress curve is the characteristic of superelasticity of bulk shape memory alloys upon tension/compression loading. However, recent studies show that such transformation plateau is hard to see when the sample size of shape memory alloys decreases to submicrons. In order to see what happened in such small scale samples during loading, in-situ compression test has been done with single crystal Cu-14.2Al-4.0Ni (wt %) submicron pillars. Our in-situ observation during compression demonstrates that the stress-induced martensitic transformation indeed occurs in submicron pillars, but is not suppressed. Furthermore, the transformation proceeds in a sequential nucleation-growth-nucleation dominated mode, but not the transient way like that in bulk materials. As a result, the stress keeps increasing throughout the transformation and no obvious transformation plateau can be detected. However, the underlying reason for such contrast transformation behaviors between our submicron pillars and bulk materials still needs further investigation.

On Deformation of A-M Interface in Single Crystal Shape Memory Alloys and Some Related Issues

1999 ◽  
Vol 121 (1) ◽  
pp. 38-43 ◽  
Author(s):  
Qing-Ping Sun ◽  
Terry Ting Xu ◽  
Xiangyang Zhang
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory Alloys ◽  
Single Crystal ◽  
Shape Memory ◽  
Deformation Field ◽  
Experimental Results ◽  
Crystal Shape ◽  
Invariant Plane ◽  
Experimental Discovery ◽  
Deformation Features

Recent experimental results on the deformation field of single crystal CuNiAl shape memory alloys (SMA) by using Moire´ interference technique are reported and two kinds of austenite-martensite (A-M) interfaces with different deformation features are identified. The experimental discovery questioned the invariant plane hypothesis used in crystallographic theory of martensitic transformation. Some fundamental issues on the property of A-M interface and the related micro- and macro-deformation features are discussed.

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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