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High temperature nanomechanics

le 7 novembre 2013
13h30

Javier LLORCA IMDEA Materials Institute, 28906 – Getafe, Madrid, Spain & Department of Materials Science, Polytechnic University of Madrid, 28040 – Madrid, Spain.

Javier LLORCA

Javier LLORCA

Nanomechanics and micromechanics experiments have become very popular in recent years as they provide unique evidence of the deformation and damage processes at the µm and nm scale. This information is of paramount importance to design novel materials with optimized properties, to develop physically-based models (as opposed to phenomenological ones) of the mechanical behavior and to explore size effects in the realm of nanotechnology. Basic experimental techniques to achieve these goals involve either in situ mechanical testing within a microscope (so the actual deformation and damage processes can be resolved at the submicron scale), instrumented nanoindentation (in which a very small volume is deformed) or a combination of both. In addition to the experimental challenges, nanomechanics often requires the use of sophisticated simulations tools (atomistics, dislocation dynamics, crystal plasticity, etc.) to interpret the results.

A further challenge in nanomechanics is the extension to high temperature. This is important from the theoretical point of view, as many deformation mechanisms are thermally-activated, as well as from the engineering side. In fact, many current or intended applications of nanostructured materials (metal-ceramic nanoscale multilayers in integrated circuits interconnects, high absorbance coatings in thermo-solar applications, radiation-resistant nanostructured metals, etc.) involve operation at high temperature. However, the field of high temperature nanomechanics is a rather unexplored area because of the challenges associated with thermal drift (while trying to measure nm), oxidation, chemical reactions and microstructure evolution in very small specimens or nanostructured materials.

In this seminar, the current activities at IMDEA Materials Institute on the area of high temperature nanomechanics will be reviewed. They include the competition among different deformation mechanisms (slip and twinning) in Mg-Al-Zn and Mg-Mn-RE alloys as a function of temperature [1-2], and the determination of the size and temperature effects on deformation mechanisms of LiF [111] micropillars [3] and of Al/SiC metal-ceramic nanoscale multilayers [4-5]. Experimental results will be interpreted and understood to the light of dislocation dynamics and crystal plasticity simulations (in the case of LiF micropillars) and of finite element modeling (Al/SiC multilayers).


[1] C. J. Boehlert, Z. Chen, I. Gutiérrez-Urrutia, J. LLorca, M. T. Pérez-Prado Acta Materialia, 60, 1889-1904, 2012.

[2] C. Boehlert Z. Chen, I. Gutiérrez-Urrutia, J. LLorca, J. Bohlen, S. Yi, D. Letzig, M. T. Pérez-Prado. Philosophical Magazine, 93, 598-617, 2013.

[3] R. Soler, J. M. Molina-Aldareguía, J. Segurado, J. LLorca, R. I. Merino, V. M. Orera. International Journal of Plasticity, 36, 50-63, 2012.

[4] S. Loftian, J. M. Molina-Aldareguía, K. E. Yazzie, J. LLorca, N. Chawla. Philosophical Magazine Letters, 92, 362-367, 2012.

[5] S. Lotfian, M. Rodríguez, K. E. Yazzie, N. Chawla, J. LLorca, J. M. Molina-Aldareguía. Acta Materialia, 61, 4439-4451, 2013.





Type :
Séminaires - conférences
Lieu(x) :
Campus de Cachan
Amphi e-média
Bâtiment Léonard De Vinci de - ENS Cachan
61, avenue du Président Wilson 94230 Cachan
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