Grain Size Effects on Young’s Modulus and Hardness of Nanocrystalline NiTi Shape Memory Alloy

2017 ◽  
pp. 203-210 ◽  
Author(s):  
Minglu Xia ◽  
Pan Liu ◽  
Qingping Sun
Keyword(s):  
Grain Size ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Young’S Modulus ◽  
Size Effects ◽  
Young's Modulus ◽  
Niti Shape Memory Alloy ◽  
Grain Size Effects

Grain size effects on NiTi shape memory alloy fatigue crack growth

2017 ◽  
Vol 33 (2) ◽  
pp. 91-107 ◽  
Author(s):  
William S. LePage ◽  
Aslan Ahadi ◽  
William C. Lenthe ◽  
Qing-Ping Sun ◽  
Tresa M. Pollock ◽  
...  
Keyword(s):  
Grain Size ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Crack Growth ◽  
Size Effects ◽  
Niti Shape Memory Alloy ◽  
Image Position ◽  
Grain Size Effects

Abstract

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.

Nucleation of martensite and thermal hysteresis of the young’s modulus in a Ni50.8Ti49.2 shape memory alloy

1999 ◽  
Vol 41 (11) ◽  
pp. 1211-1216 ◽  
Author(s):  
R. Campanella ◽  
B. Coluzzi ◽  
A. Biscarini ◽  
L. Trotta ◽  
G. Mazzolai ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Young’S Modulus ◽  
Thermal Hysteresis ◽  
Young's Modulus

A micromechanics-based constitutive model for nanocrystalline shape memory alloys incorporating grain size effects

2021 ◽  
pp. 1045389X2110282
Author(s):  
Xiang Zhu ◽  
Guansuo Dui ◽  
Yicong Zheng
Keyword(s):  
Grain Size ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Size Effects ◽  
Boundary Phase ◽  
Length Scale ◽  
Internal Length ◽  
Length Scales ◽  
Size Dependent ◽  
Grain Size Effects

A micromechanics-based model is developed to capture the grain-size dependent superelasticity of nanocrystalline shape memory alloys (SMAs). Grain-size effects are incorporated in the proposed model through definition of dissipative length scale and energetic length scale parameters. In this paper, nanocrystalline SMAs are considered as two-phase composites consisting of the grain-core phase and the grain-boundary phase. Based on the Gibbs free energy including the spatial gradient of the martensite volume fraction, a new transformation function determining the evolution law for transformation strain is derived. Using micromechanical averaging techniques, the grain-size-dependent superelastic behavior of nanocrystalline SMAs can be described. The internal length scales are calibrated using experimental results from published literature. In addition, model validation is performed by comparing the model predictions with the corresponding experimental data on nanostructured NiTi polycrystalline SMA. Finally, effects of the internal length scales on the critical stresses for forward and reverse transformations, the hysteresis loop area (transformation dissipation energy), and the strain hardening are investigated.

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