Buffiere J.-Y.,CNRS Laboratory for Materials: Engineering and Science |
Maire E.,CNRS Laboratory for Materials: Engineering and Science |
Adrien J.,CNRS Laboratory for Materials: Engineering and Science |
Masse J.-P.,SIMaP |
Boller E.,European Synchrotron Radiation Facility
Experimental Mechanics | Year: 2010
This paper aims at illustrating the potential of X-ray tomography for studying the mechanical behaviour of materials through in situ experiments. Typical experimental tomography set ups which use laboratory and synchrotron X ray sources are described; advantages and limitations of both types of sources are presented. Dedicated experimental devices which allow deformation and/or temperature changes to be applied to various types of materials are described. Examples of results of in situ mechanical experiments are presented and discussed; they include monotonic tensile testing of steel fiber entanglements, high temperature compression and room temperature fatigue of Al alloys. Examples of quantitative assessment of localisation of deformation in the interior of optically opaque samples under mechanical loading are also described. © Society for Experimental Mechanics 2010.
Galand R.,STMicroelectronics |
Clement L.,STMicroelectronics |
Waltz P.,STMicroelectronics |
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010
In this article, we focus on the characterization of copper interconnect by Electron Backscattered Diffraction (EBSD) in the final aim of reliability issue investigation. In a first time we demonstrate that we achieve to characterize copper lines of 70 nm width after some improvements in sample preparation. Then, after showing that EBSD is well adapted to characterize our structure even for very small dimensions (line width smaller than 100 nm), we propose to associate Transmission Electron Microscope in scanning mode (STEM) to complete information given by EBSD and localize defects due to electromigration. We begin by highlighting the very good correspondence between EBSD map and STEM images on line with small microstructure and finally we apply both techniques on a tested copper line after electromigration. In this case we show the relevance of using STEM to localize the defect due to electromigration which can not be seen on EBSD map. © 2010 Copyright SPIE - The International Society for Optical Engineering.
Grenet T.,CNRS Neel Institute |
Delahaye J.,CNRS Neel Institute |
Journal of Physics: Conference Series | Year: 2012
We focus on the slow relaxations observed in the conductance of disordered insulators at low temperature (especially granular aluminum films). They manifest themselves as a temporal logarithmic decrease of the conductance after a quench from high temperatures and the concomitant appearance of a field effect anomaly centered on the gate voltage maintained. We are first interested in ageing effects, i.e. the age dependence of the dynamical properties of the system. We stress that the formation of a second field effect anomaly at a different gate voltage is not a "history free" logarithmic (lnt) process, but departs from lnt in a way which encodes the system's age. The apparent relaxation time distribution extracted from the observed relaxations is thus not "constant" but evolves with time. We discuss what defines the age of the system and what external perturbation out of equilibrium does or does not rejuvenate it. We further discuss the problem of relaxation times and comment on the commonly used "two dip" experimental protocol aimed at extracting "characteristic times" for the glassy systems (granular aluminum, doped indium oxide...). We show that it is inoperable for systems like granular Al and probably highly doped InO x where it provides a trivial value only determined by the experimental protocol. But in cases where different values are obtained like in lightly doped InO x or some ultra thin metal films, potentially interesting information can be obtained, possibly about the "short time" dynamics of the different systems. Present ideas about the effect of doping on the glassiness of disordered insulators may also have to be reconsidered.
Li X.,Shanghai University |
Ren Z.,Shanghai University |
Shen Y.,Shanghai University |
Philosophical Magazine Letters | Year: 2012
By eliminating the effect of the magnetic moment arising from the magnetic crystalline anisotropy, the effect of the thermoelectric magnetic force on the array of dendrites during directional solidification of Al-35wt%Cu and Al-40wt%Cu alloys in a high magnetic field has been investigated experimentally. The results indicate that the dendrite array is essentially destroyed, a result that could have general significance for understanding the processes involved in the solidification of alloys in a magnetic field. © 2012 Taylor & Francis.
Wargnier H.,University of Bordeaux 1 |
Kromm F.X.,University of Bordeaux 1 |
Danis M.,University of Bordeaux 1 |
Materials and Design | Year: 2014
This paper describes a proposal for a multi-material design procedure. First, the context of the study and the requirements of the multi-material must be clearly defined in order to specify the parameters that the designer must select or optimise in order to produce the design: the components and their volume fraction, the architecture and morphology at different scales, etc. The general design procedure proposed here starts with the reasons why the designer has turned to multi-materials, from which a multi-material concept with fixed parameters can be defined. In this first stage the design problem can be made less complex by reducing the number of unknown parameters and guiding the designer towards the appropriate selection or optimisation tools: (i) subdivision of requirements, guided by applying statistical analysis tools to the materials database to search for appropriate multi-material components, (ii) tools to filter the materials database and search for multi-material components and their volume fraction, (iii) optimisation tools to search for the appropriate architecture when components are known or to search for architecture and components simultaneously. The paper demonstrates how these tools can be applied to different design concepts. © 2013 Elsevier Ltd.