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Séminaire « Mécanismes de la croissance » de l’INSP

Microstructural Pattern Formation during Liquid Metal Dealloying - Alain Karma - Vendredi 14 octobre 2016 à 11 h

INSP - UPMC - 4 place Jussieu - 75005 Paris - Barre 22-12, 4e étage, salle 426

Alain Karma - NorthEastern University - Boston


Microstructural Pattern Formation during Liquid Metal Dealloying Liquid metal dealloying (LMD) has emerged as a novel technique to produce topologically complex nanoporous and nanocomposite structures with ultra-high interfacial area and other unique properties relevant for diverse materials applications, exemplified by Si for battery anodes with extremely long cycle fatigue, nonporous Nb for electrolytic capacitors, or Cu-Ta nano-composites with outstanding material properties. LMD offers similar advantages as the traditional electrochemical dealloying method for forming desirable structures, but is applicable to a larger class of materials by using a liquid metal instead of an acid bath as conduit for the selective dissolution of one element of a multicomponent alloy. How dealloyed structures form has remained somewhat of a mystery. I will discuss the results of a recent collaborative study with P.-A. Geslin, Ian McCue, and J. Erlebacher, which combines phase-field simulations, experiments, and theoretical analysis to unlock this mystery. Simulations and experimental observations reveal how diffusion-limited interfacial and bulk transport phenomena interact to form a rich variety of topologically disconnected and connected structures. Moreover, analysis of the results yields scaling laws governing nano/microstructural lengthscales and dealloying kinetics that provide a quantitative theoretical basis for controlling dealloyed structures.

Alain Karma is a Professor of Physics and Arts and Sciences Distinguished Professor at Northeastern University where he directs the Center for Interdisciplinary Research on Complex Systems. His research interests span the theoretical study of nonequilibrium phenomena and interface patterns in materials, the nonlinear dynamics of heart rhythm disorders, and systems biology.

Contact : S. Akamatsu ; silvere.akamatsu – 01 44 27 63 99