|Événements du mois|
Rémi Dingreville (Sandia National Labs, Albuquerque, New Mexico, USA) est invité au LEM3 dans le cadre de l'action WP5 ("Multiscale Modeling") du Labex DAMAS pour un séminaire intitulé :
"From coherent to incoherent mismatched interfaces : a generalized continuum formulation of surface stress"
Date et lieu :
Mercredi 17 juin 2015 à 11h00
(Bat. C, LEM3, RDC)
The equilibrium of coherent and incoherent mismatched interfaces is reformulated in the context of continuum mechanics based on the Gibbs dividing surface concept . Two surface stresses are introduced: a coherent surface stress and an incoherent surface stress, as well as a transverse excess strain. The coherent surface stress and the transverse excess strain represent the thermodynamic driving forces of stretching the interface while the incoherent surface stress represents the driving force of stretching one crystal while holding the other fixed and thereby altering the structure of the interface. These three quantities fully characterize the elastic behavior of coherent and incoherent interfaces as a function of the in-plane strain, the transverse stress and the mismatch strain. The isotropic case is developed in detail and particular attention is paid to the case of interfacial thermo-elasticity. This exercise provides an insight on the physical significance of the interfacial elastic constants introduced in the formulation and illustrates the obvious coupling between the interface
structure and its associated thermodynamics quantities. Finally, illustrations based on atomistic simulations of Cu [2, 3] and Cu/Cu2O interfaces  is given to demonstrate the relevance of the generalized interfacial formulation and to emphasize the dependence of the interfacial thermodynamic quantities on the incoherency strain with an actual material system.
Dr. Dingreville is a Principal Member of the Technical Staff at Sandia National Laboratories (SNL), Albuquerque, New Mexico, USA and is currently in the Structural and Thermal Analysis Department within the Nuclear Energy and Fuel Cycle Programs Center. He holds a PhD in Mechanical Engineering from the Georgia Institute of Technology, Atlanta GA USA (2008). His Ph.D. dissertation was on upscaling theories of atomistic description to a continuum approach of interfaces in nanostructured materials and was supervised by Professor Jianmin Qu. From 2007 to 2009, he was a post-doctoral fellow at Sandia National Laboratories in the Department of Computational Materials Science. During this period his research focused on the theory of defect/microstructure interactions, crystal plasticity finite element analysis and its application to microstructure evolution. From 2009 to 2011, he was an Assistant Professor at the New York University, where he worked on stress-induced texture evolution with inelastic effects, nanomechanics, surface structure, and mesoscale modeling. In 2011, he moved back to Sandia National Laboratories in the Department of Structural and Thermal Analysis. At Sandia, Dr. Dingreville’s research areas include microstructural effects in materials performance and aging, irradiation effects in structural materials, probabilistic mechanics and uncertainty quantification, and mechanics of generalized continua. Dr. Dingreville leads several projects related to materials performance and aging and his research is supported by various agencies including DoE, NSF, NRC and SNL's LDRD.
 Dingreville R., A. Halli and S. Berbenni From coherent to incoherent mismatched
interfaces: A generalized continuum formulation of surface stresses,
Journal of the Mechanics and Physics of Solids, 72 pp. 40–60 (2014).
 Dingreville, R., and J. Qu., Interfacial excess energy, excess stress and excess
strain in elastic solids: planar interfaces. Journal of the Mechanics and
Physics of Solids, 56 (5) pp. 1944–1954 (2008).
 Dingreville, R., and J. Qu., A semi-analytical method to estimate interface
elastic properties.Computational Materials Science, 46 (1) pp. 83–91 (2009).