Effects of Ni and Co on Phase Transformation and Shape Memory Effect of Ti–Pd–Zr Alloys

This project is investigates of NiTi shape memory alloy for simple smart application. The shape memory effect (SME) is attributed from the reversible phase transformation when subjected to stress and temperature. In this study, a small model of CAMAR logo was designed to mimic the shape memory effect. Three samples of wire were investigated; (i) Austenitic NiTi (ii) Martensitic NiTi and (iii) commercial plain carbon steel. The reversible austenite to martensite transformation of the NiTi wire was investigated by a differential scanning calorimetry (DSC) at temperatures ranging from -50 and 200oC. The wire was shaped into CAMAR logo using a mould and then heated at 500°C for 30 minutes in a high temperature furnace. To observe the shape effect recovery, the wire was straighten and reheated in warm water at different temperatures. Results showed that the austenitic wire exhibited complete shape memory recovery after heated at temperature approximately 35°C and 80°C. For the martensitic wire, complete recovery was only observed when the water temperature was ~ 80°C and no recovery was observed at ~30°C. This recovery effect was significantly influenced by the reversible phase transformation temperatures (PTTs) which attributed from the Austenite finish (Af) temperature.

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Phase Transformation and Microstructures in Ni and Cu Base Ferromagnetic Shape Memory Alloys

Materials Science Forum ◽

10.4028/www.scientific.net/msf.539-543.3157 ◽

2007 ◽

Vol 539-543 ◽

pp. 3157-3162 ◽

Cited By ~ 2

Author(s):

Takuro Kushima ◽

Koichi Tsuchiya ◽

Yasuyoshi Sho ◽

Takafumi Yamada ◽

Yoshikazu Todaka ◽

...

Keyword(s):

Phase Transformation ◽

Magnetic Property ◽

Chemical Composition ◽

Martensitic Transformation ◽

Curie Temperature ◽

Shape Memory ◽

Shape Memory Effect ◽

Memory Effect ◽

Ferromagnetic Shape Memory Alloys ◽

Ferromagnetic Shape Memory

Effect of chemical composition was investigated on martensitic transformation temperatures, Curie temperature, magnetization and microstructures for Ni-(Mn, Fe, Co)-Ga and Cu-Mn-Ga systems. In the Ni-(Mn, Fe, Co)-Ga alloys, which is a modification of Ni-Mn-Ga systems, the Af and TC over 400 K were achieved. Cu-Mn-Ga alloy exhibited shape memory effect at temperatures above 373 K and had TC over 400 K. Furthermore, Cu-Mn-Ga exhibits good ductility even in polycrystalline condition unlike the case of Ni-Mn-Ga. Effect of addition of the fourth element to improve the magnetic property is under investigation.

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Phase transformation and structure of functionally graded Ni–Ti bi-layer thin films with two-way shape memory effect

Sensors and Actuators A Physical ◽

10.1016/j.sna.2015.03.014 ◽

2015 ◽

Vol 228 ◽

pp. 151-158 ◽

Cited By ~ 9

Author(s):

Maryam Mohri ◽

Mahmoud Nili-Ahmadabadi

Keyword(s):

Thin Films ◽

Phase Transformation ◽

Shape Memory ◽

Shape Memory Effect ◽

Memory Effect ◽

Functionally Graded

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A computational study of shape memory effect and pseudoelasticity of NiTi alloy under uniaxial tension during complete and partial phase transformation

Materials Research Express ◽

10.1088/2053-1591/ab06e1 ◽

2019 ◽

Vol 6 (5) ◽

pp. 055702 ◽

Cited By ~ 1

Author(s):

Rajat Rastogi ◽

S J Pawar

Keyword(s):

Phase Transformation ◽

Shape Memory ◽

Uniaxial Tension ◽

Shape Memory Effect ◽

Memory Effect ◽

Computational Study ◽

Niti Alloy ◽

Partial Phase

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Actuation of a carbon/epoxy beam using shape memory alloy wires

Journal of Intelligent Material Systems and Structures ◽

10.1177/1045389x18810807 ◽

2018 ◽

Vol 30 (2) ◽

pp. 186-197 ◽

Cited By ~ 3

Author(s):

Reza Damansabz ◽

Fathollah Taheri-Behrooz

Keyword(s):

Phase Transformation ◽

Shape Memory Alloy ◽

Shape Memory ◽

Shape Memory Effect ◽

Memory Effect ◽

Hybrid Composite ◽

Epoxy Composite ◽

Numerical Study ◽

Cohesive Zone Modeling ◽

Host Structure

Shape memory effect of NiTi wires is utilized to design various smart composite structures. In these systems, smart wires can induce strains in the host structure by their inherent shape memory effect and phase transformation at elevated temperatures. This article presents an experimental and numerical study on the actuation capability of shape memory alloy wires embedded in the carbon/epoxy composite. In the experimental part, hybrid shape memory alloy/carbon/epoxy composite specimens are fabricated and examined to measure induced strains in the host structure by the phase transformation of the shape memory alloy wires. Hybrid composite specimens were clamped at one end, and the shape memory alloy wires were activated using electrical resistive heating. Numerical simulations were carried out using ABAQUS software to simulate the actual thermomechanical behavior of the hybrid composite specimens. A three-dimensional finite element model based on cohesive zone modeling is used to predict interfacial debonding in hybrid composite plates. The results of the parametric study suggest that by increasing Young’s modulus of the host composites, the amount of the induced strain decreases rapidly. However, for Young’s moduli more than 20 GPa, the induced strain will stay almost constant. Moreover, it was confirmed that increasing the shape memory alloy pre-strain without controlling the actuation temperature may result in the reduction of induced strain in the host composites.

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