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Marc Bernacki

Bio: Marc Bernacki is an academic researcher from PSL Research University. The author has contributed to research in topics: Finite element method & Grain boundary. The author has an hindex of 33, co-authored 181 publications receiving 2768 citations. Previous affiliations of Marc Bernacki include French Institute for Research in Computer Science and Automation & Mines ParisTech.


Papers
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Journal ArticleDOI
TL;DR: In this article, a 99.995% pure Ni sample, compressed to 25%, was annealed in a SEM chamber and changes in the density of annealing twins were monitored in situ during recrystallization and grain growth.
Abstract: A 99.995% pure Ni sample, compressed to 25%, was annealed in a SEM chamber and changes in the density of annealing twins were monitored in situ during recrystallization and grain growth. In addition to average microstructural measurements, the evolution of individual grains was also observed. Both the average annealing twin density in the recrystallized domain and the annealing twin density per grain increased during recrystallization. The rate of increase in twin density correlates with the velocity of the recrystallization front. During grain growth, however, the average annealing twin density decreased. The in situ EBSD observations showed both the formation of new twins and the extension of existing twins during annealing. The observations reported here suggest that the existing models for annealing twin formation are incomplete.

167 citations

Journal ArticleDOI
07 Sep 2015
TL;DR: In this article, a quantitative analysis of features involved in recovery during annealing of deformed Tantalum is presented, where only Geometrically Necessary Dislocations (GNDs) are considered.
Abstract: The aim of this work is to present a quantitative analysis of features involved in recovery during annealing of deformed Tantalum. In pure metals where crystalline defects usually have high mobility, dislocation annihilation and rearrangement occur to a great extent prior to recrystallization. Therefore a complete understanding of recrystallization cannot be accomplished without an advanced knowledge of the recovery phenomenon. Depending on whether dislocations induce a measurable curvature in the crystal lattice or not, they are called Geometrically Necessary Dislocations (GNDs) or Statistically Stored Dislocations (SSDs) respectively. In the present work only GNDs are considered. For this purpose electron backscatter diffraction (EBSD) is an advantageous technique to obtain statistically representative results when compared to Transmission Electron Microscopy (TEM). However, a quantitative analysis of GNDs from EBSD data is not straightforward. Since local misorientations are induced by the curvature of the crystal lattice caused by GNDs, GNDs analysis can be done using local misorientations. However the values obtained from this analysis are step size dependent and influenced by the measurement noise. Reasoning on the basis that when the step size tends to zero, local misorientation should also tend to zero, measurement noise can be estimated [1]. The measurement noise appears to notably be very much dependent on the amplitude of local misorientations, which must be considered in the perspective of GND density calculation

139 citations

Journal ArticleDOI
TL;DR: In this article, the authors focus on two main domains where these properties play a major role: cleaving techniques used to obtain a thin silicon layer for photovoltaic applications and MEMS.
Abstract: Single-crystal silicon is extensively used in the semiconductor industry. Even though most of the steps during processing involve somehow thermo-mechanical treatment of silicon, we will focus on two main domains where these properties play a major role: cleaving techniques used to obtain a thin silicon layer for photovoltaic applications and MEMS. The evolution and validation of these new processes often rely on numerical simulations. The accuracy of these simulations, however, requires accurate input data for a wide temperature range. Numerous studies have been performed, and most of the needed parameters are generally available in the literature, but unfortunately, some discrepancies are observed in terms of measured data regarding fracture mechanics parameters. The aim of this article is to gather all these data and discuss the validity of these properties between room temperature and 1273 K. Particular attention is given to silicon fracture properties depending on crystallographic orientations, and to the brittle–ductile temperature transition which can strongly affect the quality of silicon layers.

126 citations

Journal ArticleDOI
TL;DR: In this paper, a level set framework for the numerical modeling of primary static recrystallization in polycrystalline material is described, and the topological evolution of the grain structure is simulated in two and three dimensions, based on a kinetic law relating the velocity of the boundary to the thermodynamic driving force.

117 citations

Journal ArticleDOI
TL;DR: In this article, a level set framework for the finite-element modeling of recrystallization in polycrystalline materials, including the nucleation, primary re-stallization and grain growth stages, is described.

110 citations


Cited by
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01 Apr 1988-Nature
TL;DR: In this paper, a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) is presented.
Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

9,929 citations

Journal ArticleDOI
TL;DR: In this paper, a review of continuum-based variational formulations for describing the elastic-plastic deformation of anisotropic heterogeneous crystalline matter is presented and compared with experiments.

1,573 citations

Journal ArticleDOI
TL;DR: In this paper, the authors review the current state of the art as CT transforms from a qualitative diagnostic tool to a quantitative one, including the use of iterative reconstruction strategies suited to specific segmentation tasks and emerging methods that provide more insight than conventional attenuation based tomography.
Abstract: X-ray computer tomography (CT) is fast becoming an accepted tool within the materials science community for the acquisition of 3D images. Here the authors review the current state of the art as CT transforms from a qualitative diagnostic tool to a quantitative one. Our review considers first the image acquisition process, including the use of iterative reconstruction strategies suited to specific segmentation tasks and emerging methods that provide more insight (e.g. fast and high resolution imaging, crystallite (grain) imaging) than conventional attenuation based tomography. Methods and shortcomings of CT are examined for the quantification of 3D volumetric data to extract key topological parameters such as phase fractions, phase contiguity, and damage levels as well as density variations. As a non-destructive technique, CT is an ideal means of following structural development over time via time lapse sequences of 3D images (sometimes called 3D movies or 4D imaging). This includes information nee...

1,009 citations