Change in Young's Modulus Associated with Martensitic Transformation in Shape Memory Alloys

2000 ◽  
Vol 327-328 ◽  
pp. 363-366 ◽  
Author(s):  
Koh Ichi Sugimoto ◽  
M. Nakaniwa
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Young’S Modulus ◽  
Young's Modulus

Design of Shape Memory Alloy Springs With Applications in Vibration Control

1993 ◽  
Vol 115 (1) ◽  
pp. 129-135 ◽  
Author(s):  
C. Liang ◽  
C. A. Rogers
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Vibration Control ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Design Method ◽  
Control Area ◽  
Spring Constant ◽  
Damping Capacity

Shape memory alloys (SMAs) have several unique characteristics, including their Young’s modulus-temperature relations, shape memory effects, and damping characteristics. The Young’s modulus of the high-temperature austenite of SMAs is about three to four times as large as that of low-temperature martensite. Therefore, a spring made of shape memory alloy can change its spring constant by a factor of three to four. Since a shape memory alloy spring can vary its spring constant, provide recovery stress (shape memory effect), or be designed with a high damping capacity, it may be useful in adaptive vibration control. Some vibration control concepts utilizing the unique characteristics of SMAs will be presented in this paper. Shape memory alloy springs have been used as actuators in many applications although their use in the vibration control area is very recent. Since shape memory alloys differ from conventional alloy materials in many ways, the traditional design approach for springs is not completely suitable for designing SMA springs. Some design approaches based upon linear theory have been proposed for shape memory alloy springs. A more accurate design method for SMA springs based on a new nonlinear thermomechanical constitutive relation of SMA is also presented in this paper.

The Effect of Non-Constant Young's Modulus in Modelling of Tension and Compression of Superelastic NI-TI Shape Memory Alloys

2010 ◽  
Vol 26 (4) ◽  
pp. 553-561
Author(s):  
Andrej Puksic ◽  
Janez Kunavar ◽  
Miha Brojan ◽  
Franc Kosel
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Transformation Strain ◽  
Material Model ◽  
Stress Plateau ◽  
Micromechanical Approach ◽  
Tension And Compression ◽  
Tension Compression Asymmetry

ABSTRACTMany unresolved issues remain in the field of modelling of shape memory alloys. In this paper the problem of unequal elastic properties of austenite and martensite is addressed. We propose a modification of the micromechanical material model that enables the application of different Young's modulus for austenite and martensite. The corresponding computational model for the application of the micromechanical approach to modeling of superelasticity in shape memory alloys is demonstrated. Material properties for Ni-Ti alloy (50.8 at.% Ni) obtained from literature and from our own experiments were applied to the model and a sample calculation of a 3D model subjected to uniaxial loading was performed. The results were compared to experimental results obtained from tensile and compressive tests. In general the presented model predicts well the level of the superelastic stress plateau and maximum transformation strain in tension. The agreement in compression is worse but the overall characteristics of the tension-compression asymmetry are predicted correctly.

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.

Sign in / Sign up

Export Citation Format

Share Document