Kinetics and morphological evolution of liquid metal dealloying

• Published in: Acta materialia Vol. 115; no. C; pp. 10 - 23
• Main Authors: McCue, Ian, Gaskey, Bernard, Geslin, Pierre-Antoine, Karma, Alain, Erlebacher, Jonah
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 01.08.2016; Elsevier
• Subjects: Alloys; Chemical Sciences; Composites; Composition effects; Dealloying; Diffusion; Dissolution; Engineering Sciences; Evolution; Kinetics; Liquid metals; Metals; Physics; Titanium base alloys; Composites; Kinetics; Diffusion; Dealloying; Metals
• ISSN: 1359-6454; 1873-2453
• DOI: 10.1016/j.actamat.2016.05.032

Liquid metal dealloying (LMD) has recently emerged as a novel technique to fabricate bulk nanostructures using a bottom-up self-organization method, but the literature lacks fundamental studies of this kinetic process. In this work, we conduct an in-depth study of the kinetics and fundamental microstructure evolution mechanisms during LMD using TiTa alloys immersed in molten Cu as a model system. We develop a model of LMD kinetics based on a quantitative characterization of the effects of key parameters in our system including alloy composition, dealloying duration, and dealloying temperature. This work demonstrates that the dealloying interface is at or near equilibrium during LMD, and that the rate-limiting step is the liquid-state diffusion of dissolving atoms away from the dealloying interface (diffusion-limited kinetics). The quantitative comparison between theoretically predicted and measured dealloying rates further reveals that convective transport and rejection of the dissolving element during coarsening of the structure also influence the dealloying kinetics. [Display omitted]