The Electric Resistance of Shape Memory Alloys in the Pseudoelastic Regime

Airoldi, G.; Lodi, D.A.; Pozzi, Michele

doi:10.1051/jp4:1997580

Cited by 12 publications

(11 citation statements)

References 4 publications

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“…Such observation, however, is not unique and has been documented by Airoldi et al (1998) and Novak et al (2008) in the elastic strain range. The initial decrement in the electric resistance is possibly contributed by the change in resistivity of Cu-Al-Mn SEA bar.…”

Section: Discussionmentioning

confidence: 77%

“…And it exhibits a negative gage factor for small strain region up to 0.8% strain for Cu-Al-Mn SEAs as reported earlier due to changes in resistivity for the applied elastic strains. Hence, calibration of such SEA bar as sensor would (Airoldi et al, 1998) 0.033 70-84.5 2.5 8.40 Cu-Al-Be wire (Airoldi et al, 1998) 0 require definition of two distinct regions, before and after the start of transformation. As illustrated in Table 1, the previous works have been mainly done on SEAs of wire samples or thin plates.…”

Section: Discussionmentioning

confidence: 99%

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Feasibility of Cu-Al-Mn superelastic alloy bar as a self-sensor material

Shrestha

Araki

Yamakawa

et al. 2014

Journal of Intelligent Material Systems and Structures

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This article examines the feasibility of Cu-Al-Mn superelastic alloy bars as possible self-sensor components, taking electrical resistance measurement as a feedback. Superelastic alloy bars change their crystallographic structure with phase transformation, as well as electrical resistance during loading-unloading process at ambient temperature. This work studies the relationship between strain and electrical resistance measurements of superelastic alloys at room temperature. Such relationship can be used in determining the state of a shape memory alloy-based structure effectively, without separate sensors, by appropriately measuring the changes in electrical resistance during and after structure's loading history. Quasi-static cyclic tensile tests are conducted in this article to investigate the relationship between electrical resistance and strain for a 4-mm-diameter Cu-Al-Mn superelastic alloy bar. It was demonstrated that linear relationship with little hysteresis can be achieved up to 10% strain. The test observations support the feasibility of newly developed Cu-Al-Mn superelastic alloy bars, characterized by low material cost and high machinability, as a multifunctional material for both structural and sensing elements.

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Section: Discussionmentioning

confidence: 77%

Section: Discussionmentioning

confidence: 99%

Feasibility of Cu-Al-Mn superelastic alloy bar as a self-sensor material

Shrestha

Araki

Yamakawa

et al. 2014

Journal of Intelligent Material Systems and Structures

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“…This variation cannot only be explained by geometric alterations of samples, but is also related to martensite variants reorientation process [11,12]. In these tests, a negative change of ER was attributed the presence of the R phase [13].…”

Section: Introductionmentioning

confidence: 84%

Behaviour of electrical resistivity in single crystals of Cu-Zn-Al and Cu-Al-Be under stress

2001

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Abstract. Electrical resistivity measurement (ER) has been one of the main experimental techniques used in researches that involve alloys with martensitic transformation, due to its susceptibly to detect crystalline structure modifications. In alloys that present shape memory effect, ER is mainly used to study thermal cycling and ageing. Recently, measures of electrical resistance have been coupled to mechanical tests during shape memory effect phenomena. Most of publications using ER at constant temperature in the stress-strain domain was done in polycrystalline alloys of Ti-Ni and Ti-Ni-Cu. In this work, single crystals of copper-based samples were tested at different temperatures to analyse the behaviour of stress and resistivity variation versus strain. During superelasticity test, ER variation presents a linear behaviour and an absence of hysteresis with strain. Mechanical tests are performed at different temperatures and with different orientations of the tensile axis. These results show that the martensite variants present an electrical anisotropy.

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“…Using these probes, transformation behavior has been studied extensively by many researchers [6][7][8][9][10][11]. The present author has used differential scanning calorimeter (DSC) for the study of transformation temperature and recoverable strain which are the two main design parameters in applications.…”

Section: Introductionmentioning

confidence: 99%

Shape memory alloys — characterization techniques

Uchil

2002

Pramana - J Phys

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Shape memory alloys are the generic class of alloys that show both thermal and mechanical memory. The basic physics involved in the shape memory effect is the reversible thermoelastic martensitic transformation. In general, there exists two phases in shape memory alloys, viz., a hightemperature phase or austenitic phase (A) and a low-temperature phase or martensitic phase (M). In addition, an intermediate R phase exists in some special cases. The M↔A transformation is associated with a recoverable strain of about 6.5-8% and the R↔A transformation is associated with a recoverable strain of about 1%. The former transformation has been widely used in the applications like antenna deployment of satellite, aerospace couplings, orthodontic arch wires, medical guide wires for diagnostic and therapeutic catheters and other industrial applications. Our group has been giving emphasis to the characterization techniques for R phase, using differential scanning calorimetry (DSC), electrical resistivity probe (ER) and thermomechanical analyzer (TMA). R phase is found to have attractive features like stability against thermal cycling, a small thermal hysteresis and a negligible strain recovery fatigue. DSC has been used successfully to characterize the recoverable strain parameters, apart from the determination of transformation temperatures. ER is used, for the systematic study of the dependence of various phases on heat-treatment temperatures. TMA has been effectively employed for the study of the mixed phases. A space-rotating platform is designed and fabricated, using an actuator of shape memory spring, for obtaining controlled rotations. The efficiency and the reliability of this actuator has been tested, over a million thermal cycles.

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The Electric Resistance of Shape Memory Alloys in the Pseudoelastic Regime

Cited by 12 publications

References 4 publications

Feasibility of Cu-Al-Mn superelastic alloy bar as a self-sensor material

Feasibility of Cu-Al-Mn superelastic alloy bar as a self-sensor material

Behaviour of electrical resistivity in single crystals of Cu-Zn-Al and Cu-Al-Be under stress

Shape memory alloys — characterization techniques

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