Grain size effects on stability of nonlinear vibration with nanocrystalline NiTi shape memory alloy

2017 ◽  
Vol 26 (10) ◽  
pp. 105033 ◽  
Author(s):  
Minglu Xia ◽  
Qingping Sun
Keyword(s):  
Grain Size ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Nonlinear Vibration ◽  
Size Effects ◽  
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

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.

Simulation of grain size effects in nanocrystalline shape memory alloys

2015 ◽  
Vol 117 (24) ◽  
pp. 244305 ◽  
Author(s):  
Rajeev Ahluwalia ◽  
Siu Sin Quek ◽  
David T. Wu
Keyword(s):  
Grain Size ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Size Effects ◽  
Grain Size Effects
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