A note on: “Monotone strain-stress models for shape memory alloys hysteresis loop and pseudoelastic behavior” [Z. Angew. Math. Phys. (ZAMP) 56 (2005), 304–356]

2007 ◽  
Vol 59 (1) ◽  
pp. 181-185
Author(s):  
Aida Timofte ◽  
Vlad Timofte
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Hysteresis Loop ◽  
Strain Stress ◽  
Stress Models ◽  
Math Phys ◽  
Pseudoelastic Behavior

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.

scholarly journals Understanding the Shape-Memory Alloys Used in Orthodontics

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Daniel J. Fernandes ◽  
Rafael V. Peres ◽  
Alvaro M. Mendes ◽  
Carlos N. Elias
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Nickel Titanium ◽  
Orthodontic Wires ◽  
Steel Alloys ◽  
Thermomechanical Characteristics ◽  
Shape Memory Properties ◽  
Niti Wires ◽  
Niti Shape Memory Alloys ◽  
Pseudoelastic Behavior

Nickel-titanium (NiTi) shape-memory alloys (SMAs) have been used in the manufacture of orthodontic wires due to their shape memory properties, super-elasticity, high ductility, and resistance to corrosion. SMAs have greater strength and lower modulus of elasticity when compared with stainless steel alloys. The pseudoelastic behavior of NiTi wires means that on unloading they return to their original shape by delivering light continuous forces over a wider range of deformation which is claimed to allow dental displacements. The aim of this paper is to discuss the physical, metallurgical, and mechanical properties of NiTi used in Orthodontics in order to analyze the shape memory properties, super-elasticity, and thermomechanical characteristics of SMA.

scholarly journals Effects of B2 nanoprecipitates on the phase stability and pseudoelastic behavior of Fe-Mn-Al-Ni shape memory alloys

2015 ◽  
Vol 33 ◽  
pp. 04005 ◽  
Author(s):  
P. La Roca ◽  
J. Medina ◽  
C.E. Sobrero ◽  
M. Avalos ◽  
J.A. Malarria ◽  
...  
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Phase Stability ◽  
Pseudoelastic Behavior

A mechanical contact model for superelastic shape memory alloys

2020 ◽  
pp. 1045389X2095361
Author(s):  
Mohammad Sattari ◽  
Hossein Ashtari Esfahani ◽  
Mahmoud Kadkhodaei ◽  
Saleh Akbarzadeh
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Constitutive Equations ◽  
Contact Model ◽  
Stress And Strain ◽  
Resistant Material ◽  
Niti Wire ◽  
Contact Models ◽  
Acceptable Agreement ◽  
Pseudoelastic Behavior

Shape memory alloys (SMA) are nowadays widely used in different industries. The two extraordinary behaviors of superelasticity and shape memory effect make these alloys a super wear-resistant material. In a range of SMA applications, contact between adjacent surfaces occurs. In this research, a formerly-developed contact model, which individually considers each asperity, is extended to cases where superelastic shape memory alloys are used. Since constitutive equations of SMAs are based on stress and strain, to establish a relationship between classical contact models and the main arguments of these constitutive equations, a representative strain based on the pseudoelastic behavior of SMAs was defined. Experiments were conducted to verify the model’s predictions. In these experiments, a NiTi wire was pressed against a Steel plate; then, the measured penetration in the test and the values predicted by the contact model were compared. The reported results show an acceptable agreement between theory and experiment.

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