Alain Karma, Physics Department and Center for Interdisciplinary Research on Complex Systems Northeastern University, Boston, USA 

Abstract:

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-Tananocomposites with outstanding mechanical properties. LMD offers similar advantages as the traditional electrochemical dealloying method, 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 review the rich history of dealloying and discuss the results of a combined experimental and computational modeling study [1] that sheds light on basic mechanisms of interfacial pattern formation during LMD. Simulations 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.

[1]  “Topology-generating interfacial pattern formation during liquid metal dealloying”, P.-A. Geslin, I. McCue, J. Erlebacher, and A. Karma, Nature Communications 6, 9887 (2015).

Site web du groupe de  http://www.northeastern.edu/cos/faculty/alain-karma/

Cette conférence est présentée par le RQMP Versant Nord du Département de physique de l'Université de Montréal et le Département de génie physique de Polytechnique Montréal.