Investigation of martensitic microstructures in a monocrystalline Cu–Al–Be shape memory alloy with the grid method and infrared thermography

Delpueyo, D.; Grédiac, Michel; Balandraud, Xavier; Bădulescu, Claudiu

doi:10.1016/j.mechmat.2011.09.007

Cited by 34 publications

(34 citation statements)

References 25 publications

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“…1 (see also [34] We measured the in-plane displacement, the linear strain components and the local rotation on the gauge region of the sample through the grid method. This technique derives these quantities from the images of a grid captured by a camera as the sample deforms under the loading.…”

Section: Appendixmentioning

confidence: 99%

Strain intermittency in shape-memory alloys

et al. 2015

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We study experimentally the intermittent progress of the mechanically-induced martensitic transformation in a Cu-Al-Be single crystal through a full-field measurement technique: the grid method. We utilize an in-house especially designed gravity-based device, wherein a system controlled by water pumps applies a perfectly monotonic uniaxial load through very small force increments. The sample exhibits hysteretic superelastic behavior during the forward and reverse cubic-monoclinic transformation, produced by the evolution of the strain field of the phase microstructures. The in-plane linear strain components are measured on the sample surface during the loading cycle, and we characterize for the first time the strain intermittency in a number of ways, showing the emergence of power-law behavior for the strain avalanching over almost six decades of magnitude. We also describe the non-stationarity and the asymmetry observed in the forward vs. the reverse transformation. The present experimental approach, which allows for the monitoring of the reversible martensitic transformation both locally and globally in the crystal, proves useful and enhances our capabilities in the analysis and possible control of transition-related phenomena in shape-memory alloys.

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Section: Appendixmentioning

confidence: 99%

Strain intermittency in shape-memory alloys

et al. 2015

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“…Different local strain levels are observed in this map. However, it can be expected that all the martensitic zones in the specimen are characterized by a fixed transformation strain whose order of magnitude is 0.10 [12]. The different levels of local strain in the martensitic zones actually result from the image processing, which is based on the windowed Fourier transform (WFT): this value is underestimated if the martensite needle width is too small.…”

Section: Resultsmentioning

confidence: 99%

“…A comparison between DIC and digital speckle pattern correlation to measure displacement fields in a Cu-AlBe SMA was presented in Reference [10]. The grid method [11] was used on a monocrystalline Cu-Al-Be [12], including a specific procedure to limit some negative effects of unavoidable grid defects [13,14]. This procedure limited the use of spatial filtering to reduce noise in strain maps, leading to a good compromise between strain resolution and spatial resolution in strain, and thus making possible the detection of very localized phenomena such as appearance and development of thin martensite needles.…”

Section: Introductionmentioning

confidence: 99%

Study of Phase Transformation Intermittency in S.M.A. Using the Grid Method

Barrera

Balandraud

Grédiac

et al. 2014

Fracture, Fatigue, Failure, and Damage Evolution, Volume 5

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The objective of this study is to show experimentally the intermittency of the phase transformation in a shape memory alloy using a kinematical full-field measurement method. The specimen is a Cu-Al-Be single crystal with Ms D 2 ı C. A uniaxial loading was applied by using a device based on gravity. In practice, a drop-by-drop device controlled by water pumps enabled us to apply a perfectly monotonic loading with very small force increments. The grid method was used to measure the strain fields on the specimen surface during the test. It is observed that the plateau which is classically obtained when the specimen transforms from austenite to martensite is actually characterized by an intermittency of the phase change. It means that the events, in terms of appearance of martensite needles and propagation, occur with an irregular alternation. The paper presents the experimental setup, the image processing and some typical results.

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“…Considering temperature as itself is already a precious tool to characterize the response of materials or structures under mechanical loading. This analysis can be performed for homogeneous cases under monotonic or cyclic solicitations in order to include any thermal effect induced by the mechanical testing conditions (heat build-up for fatigue testing, for example), to investigate the thermo-elastic couplings (Delpueyo et al, 2012), to follow the evolution of the material microstructure (Anthony et al, 1942;Le Saux et al, 2012;Delpueyo et al, 2012) or to detect a change in the thermo-mechanical response, allowing for example to get a quick evaluation of the fatigue limit (La Rosa and Risitano, 2000;Le Saux et al, 2010). Taking advantage of the development of full field measurements techniques (and especially of infrared devices), the analysis of heterogeneous cases is also available.…”

Section: Introductionmentioning

confidence: 99%

“…The evaluation of these heat sources is clearly a key point in order to characterize and understand the thermodynamic behaviour of the sample tested. The applications lead for instance to evaluate the balance between stored and dissipated energy (Chrysochoos, 2012;Rittel, 1999), to identify the intrinsic thermo-mechanical parameters (Lemaitre and Chaboche, 1985), to detect localized phenomena (Chrysochoos et al, 2009;Wang et al, 2014) or microstructural changes (Delpueyo et al, 2012;Samaca Martinez et al, 2013) and to feed energy based criteria to predict the fatigue properties (Doudard et al, 2005;Le Saux et al, 2010).…”

Section: Introductionmentioning

confidence: 99%