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Article Dans Une Revue Physics Procedia Année : 2010

Measurement of local strain heterogeneities in superelastic shape memory alloys by digital image correlation

Résumé

This work is focused on the displacement and strain fields measurement using the Digital Image Correlation (DIC) technique on a superelastic Shape Memory Alloy (SMA) sample submitted to uniaxial tension. The local strain heterogeneities are estimated in a CuAlBe multicrystal with one grain in the thickness and millimetric grain size. Crystallographic orientation of each grain is measured by EBSD technique. Several tests are carried out on the same specimen, in front of a long distance microscope with or without speckle pattern, and at two different magnifications. Evolutions of the martensitic transformation are investigated and analysed in terms of the strain heterogeneities. In copper SMA, the important anisotropy of the elastic moduli tensor involves high intergranular elastic strain heterogeneities. Martensite variants induce steps on the specimen surface. However, the strain fields were measured for greater load levels, when the material runs through the phase transformation. These steps interfere with the speckle patterns and may perturb the correlation process. The challenge was also to apply very fine speckle to analyze the deformation in grains. The study shows that the transformation and strain localizations mainly occur in bands involving the well crystallographic oriented grains with respect to the load direction.

Dates et versions

hal-01769305 , version 1 (17-04-2018)

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Citer

Nadine Bourgeois, Fodil Meraghni, Tarak Ben Zineb. Measurement of local strain heterogeneities in superelastic shape memory alloys by digital image correlation. Physics Procedia, 2010, 10, pp.4 - 10. ⟨10.1016/j.phpro.2010.11.066⟩. ⟨hal-01769305⟩
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