Prof Javier Llorca, Polytechnic University of Madrid

High Temperature Nanomechanics
When Feb 18, 2013
from 02:00 PM to 03:00 PM
Where LR8
Contact Name
Contact Phone 01865 283302
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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 determination of the size and temperature effects on deformation mechanisms of LiF [111] micropillars, Al/SiC metal-ceramic nanoscale multilayers and Cu/Nb metallic multilayers. Experimental results will be interpreted and understood to the light of dislocation dynamics and crystal plasticity simulations (in the case of LiF micropillars), finite element modeling (Al/SiC multilayers) o theoretical models (Cu/Nb multilayers).