Unusual strain recovery in γ1′ martensite single variant of CuAlNi alloy

Ichikawa, Tsukasa; Otani, Naoki; Miyazaki, S.; Otsuka, Kazuhiro

doi:10.1016/0036-9748(89)90054-9

Cited by 5 publications

(3 citation statements)

References 12 publications

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“…Figure c shows the pseudoelastic behavior in cycle 140, which is fully reproducible once the martensite phase becomes completely stabilized and encloses a smaller area in the depth‐load space, indicating that a certain amount of mechanical energy is still dissipated during one loading‐unloading cycle. This mechanical response, named as rubber‐like behavior or pseudoelastic‐twinning, is characteristic of the martensitic state and associated to the hysteretic motion of the martensite interfaces between different variants crystallographically equivalent but with different orientations to minimize the elastic strain energy …”

Section: Resultsmentioning

confidence: 99%

“…This mechanical response, named as rubber-like behavior or pseudoelastic-twinning, is characteristic of the martensitic state and associated to the hysteretic motion of the martensite interfaces between different variants crystallographically equivalent but with different orientations to minimize the elastic strain energy. [38,39] In order to verify if the stabilized martensite phase can return back to the superelastic behavior, a slight heating of the bulk sample, not exceeding 373 K, was performed, by touching the sample with the tip of a soldering iron, to produce the reverse martensitic transformation. This slight heating is not expected to produce any other microstructural evolution because these samples have an atomic order L2 1 being thermally stable even at 473 K; diffusion processes are only activated above this temperature and dislocations in this L2 1 lattice start moving thermally at 750 K as confirmed by in-situ transmission electron microscopy and internal friction measurements.…”

Section: Anomalous Behavior During Cyclingmentioning

confidence: 99%

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Anomalous Behavior During Nano‐Compression Superelastic Tests on Cu‐Al‐Ni Shape Memory Alloy Micro Pillars

Gómez-Cortés

Nó

López‐Echarri

et al. 2018

Physica Status Solidi (a)

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Shape memory alloys are one of the most important families of functional materials due to superelasticity and shape memory properties. In particular Cu‐Al‐Ni alloys exhibit these properties at nanoscale, becoming potentially useful to design new smart MEMS. In this work, an anomalous behavior observed during nano‐compression superelastic tests on Cu‐Al‐Ni shape memory alloy micro pillars is reported. The study is approached by nano‐compression tests on micro and nano pillars milled by focused ion beam. The anomalous behavior on the superelastic effect is manifested by a sudden stabilization of the stress‐induced martensite, which does not undergo the reverse transformation. A transition, from superelastic to pseudoelastic‐twinning behavior, takes place during the nano‐compression tests, and is evaluated through the load‐depth curves and quantified by the mechanical damping coefficient η, which undergoes a sharp change from ultra‐high damping, η > 0.1, down to η ≈ 0.01. The stabilization of the martensite occurs under two different experimental conditions, along cycling and by applying a very high stress during superelastic tests. In both cases, a further recovery of the initial superelastic behavior is registered. The mechanisms responsible for the observed stabilization and recovery are discussed, together with the implications and further requirements for technological applications in MEMS.

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Section: Resultsmentioning

confidence: 99%

Section: Anomalous Behavior During Cyclingmentioning

confidence: 99%

Anomalous Behavior During Nano‐Compression Superelastic Tests on Cu‐Al‐Ni Shape Memory Alloy Micro Pillars

Gómez-Cortés

Nó

López‐Echarri

et al. 2018

Physica Status Solidi (a)

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“…This variant selection by external stress is at the origin of the transformation strain and superelasticity in shape memory alloys 39 . Otsuka and co-workers 45 – 48 have succeeded in making and investigating the deformation behaviour of single-crystalline martensite of Cu-Al-Ni SMAs by this method.…”

Section: Introductionmentioning

confidence: 99%

Plastic deformation behaviour of single-crystalline martensite of Ti-Nb shape memory alloy

Tahara

Okano

Inamura

et al. 2017

Sci Rep

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β-Ti alloys have attracted considerable attention as new biomedical shape memory alloys. Given the critical importance of the plastic deformation in the martensite phase for the shape memory effect and superelasticity, we investigated here the plastic deformation behaviour of a single crystal of α″ (orthorhombic) martensite of Ti-27 mol%Nb shape memory alloy obtained by the stress-induced martensitic transformation of a single crystal of the parent β phase. Four operative plastic deformation modes were observed, including two dislocation slips and two twinnings. To the best of our knowledge, two of these plastic deformation modes (one dislocation slip and one twinning) were discovered for the first time in this study. The identified slip and twinning systems in the martensite phase have corresponding slip and twinning systems in the parent β phase with which they share many similarities. Therefore, we believe that the plastic deformation of the α″ martensite is inherited from that of the parent β phase.

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