Cyclic pseudoelastic behavior and energy dissipation in as-cast Cu-Zn-Al foams of different densities

Bertolino, G.; Gruttadauria, Andrea; Larochette, P. Arneodo; Castrodeza, Enrique Mariano; Baruj, A.; Troiani, Horacio Esteban

doi:10.1016/j.intermet.2010.12.008

Cited by 20 publications

(15 citation statements)

References 29 publications

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“…Recently significant effort has been devoted to demonstrate their experimental viability. So far, oSMA wires and foams have been developed, and they all exhibit superior performance compared to their bulk polycrystalline counterparts 1–6. For example, Chen et al showed completely recoverable strains up to about 7% in Cu‐Al‐Ni oSMA wires which normally fracture at very small strains 1.…”

Section: Introductionmentioning

confidence: 99%

Oligocrystalline Shape Memory Alloys

Ueland

Chen

Schuh

2012

Adv Funct Materials

138

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Copper-based shape memory alloys (SMAs) exhibit excellent shape memory properties in single crystalline form. However, when they are polycrystalline, their shape memory properties are severely compromised by brittle fracture arising from transformation strain incompatibility at grain boundaries and triple junctions. Oligocrystalline shape memory alloys (oSMAs) are microstructurally designed SMA structures in which the total surface area exceeds the total grain boundary area, and triple junctions can even be completely absent. Here it is shown how an oligocrystalline structure provides a means of achieving single crystal-like SMA properties without being limited by constraints of single crystal processing. Additionally, the formation of oSMAs typically involves the reduction of the size scale of specimens, and sample size effects begin to emerge. Recent fi ndings on a size effect on the martensitic transformation in oSMAs are compared and a new regime of heat transfer associated with the transformation heat evolution in these alloys is discussed. New results on unassisted two-way shape memory and the effect of loading rate in oSMAs are also reported.

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Section: Introductionmentioning

confidence: 99%

Oligocrystalline Shape Memory Alloys

Ueland

Chen

Schuh

2012

Adv Funct Materials

138

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“…An oligocrystalline structure can be defined as one where the total surface area is greater than the total grain boundary area, meaning that grains are coordinated mostly by unconfined free surfaces rather than rigid boundaries with other grains. The oligocrystalline structures that have been studied to date in conventional SMAs are based on fine wires with a bamboo grain structure [16][17][18], with some preliminary work on open-cell foams [19,20]; the same concept has been explored in magnetic SMA foams at an even earlier date [21].…”

Section: Introductionmentioning

confidence: 99%

Superelasticity and fatigue in oligocrystalline shape memory alloy microwires

2012

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In oligocrystalline shape memory alloys, the total grain boundary area is smaller than the surface area of the specimen, leading to significant effects of free surfaces on the martensitic transformation and related shape memory and superelastic properties. Here we study sample size effects upon the superelastic characteristics of oligocrystalline microwires after one loading cycle and after many. Cu-Zn-Al wires with diameters ranging from ~100 down to ~20 µm are fabricated by the Taylor liquid processing technique and characterized through both uniaxial cyclic tensile testing and mechanically constrained thermal cycling. The energy dissipated per superelastic cycle increases with decreasing wire diameter, and this size effect is preserved after extensive cycling despite a significant transient evolution of the superelastic response for early cycles. We also present fatigue and fracture data indicating that oligocrystalline wires of this normally brittle alloy can exhibit fatigue lifetimes two orders of magnitude improved over conventional polycrystalline Cu-Zn-Al.

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“…One possibility is to use SMA as a substitute material, including SMA foams to take advantage of the positive re-centering effects. SMA CuZnAl foams with an M s temperature below room temperature (M s = 10°C) were synthesized [170,171] using the method described in Ref. [172].…”

Section: Dynamic and Recoverable Stabilization Of Cualbementioning

confidence: 99%

“…Early studies have shown very restricted pseudoelastic behavior [184][185][186], usually related to low shape recovery properties. However, recent developments on these alloys related to the introduction of NbC precipitates [187,188] and pre-deformation at intermediate temperatures [171,189] resulted in materials with excellent shape memory properties and extended pseudo-elastic ranges [190][191][192]. In particular, Sawaguchi et al [193] showed that a Fe-Mn-Si-Cr alloy containing a small amount of tiny NbC precipitates could be deformed by cycling between tension and compression, reaching a SDC of 80 % for cycles with 1 % deformation amplitude.…”

Section: Dynamic and Recoverable Stabilization Of Cualbementioning

confidence: 99%

Shape memory alloys as an effective tool to damp oscillations

Torra¹,

Isalgué

Lovey

et al. 2015

J Therm Anal Calorim

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The SMA was studied for their macroscopic application in damping for civil engineering. The study is a synthesis and includes an outline of the models required for the SMA simulation and some case studies using the finite element analysis methods. This work is an overview that focuses in the mitigation of the oscillations in structures induced by earthquakes, and for a reduction of the oscillations amplitude in stayed cables under the action of rain, wind or traffic. The analysis needs the required conditions for each application determining the working conditions. The study includes the number of working cycles, the temperature effects and the cooling actions and, for instance, the action of the cycling frequency. The main target relates the appropriateness of the SMA for each purpose, and the suitability of the SMA device is always experimentally guaranteed. Furthermore, the applicability of the obtained results for SMA and the practical behavior of the SMA dampers were studied in international facilities. The paper includes appropriate suggestions for a correct preparation of the SMA dampers. This work outlines the effects of stress and temperature aging in NiTi, describes the particular structural effects between 18R and 6R, introduces a first attempt in the dynamic properties of the CuAlBe single crystals and summarizes some recent suggestions for damping using SMA.Keywords Shape memory alloys Á Martensitic transformation Á NiTi Á CuAlBe Á Damping Á Fatigue Part oneThe martensitic transformation (MT) is the origin of the unique properties of shape memory alloys (SMA) [1,2]. MT is a first-order phase transition between metastable phases with hysteresis. The transformation takes place with small displacements of the atoms and without any change in the positions of the neighboring atoms: Atomic order is conserved in the transformation. The transformation can be induced by temperature or by external forces, such as traction or compression. In temperature-induced transformations, M s (martensite start) denotes the starting temperature. The M f (martensite finish) temperature determines the end of the transformation, and A s and A f denote the austenite start and the austenite finish temperatures, respectively. This part was devoted to general contents and properties of the SMA appropriate for damping of oscillations. In particular, reduction of oscillations appeared in civil engineering structures.

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Cyclic pseudoelastic behavior and energy dissipation in as-cast Cu-Zn-Al foams of different densities

Cited by 20 publications

References 29 publications

Oligocrystalline Shape Memory Alloys

Oligocrystalline Shape Memory Alloys

Superelasticity and fatigue in oligocrystalline shape memory alloy microwires

Shape memory alloys as an effective tool to damp oscillations

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