Structure and Dynamics of Chemically Heterogeneous Metal-metal Solid-liquid Interfaces


Seminar

Date

Time

11:00 a.m.

Location

Zoom

Presenter

Brian B. Laird (Professor, Department of Chemistry, University of Kansas)

Abstract

The properties of solid-liquid interfaces (SLIs) govern a wide variety of processes of technological import, e.g., wetting, heterogeneous nucleation, casting, and crystal morphology and growth. Here, we examine three chemically heterogeneous metal-metal SLIs, specifically Al(s)/Pb(l), Cu(s)/Pb(l) and Al(s)/Ga(l) to determine how interfacial structure and dynamics affect phenomena of experimental interest. For Al/Pb, transmission electron microscopy (TEM) experiments show that liquid Pb inclusions undergo Brownian motion within a solid Al matrix. Using molecular-dynamics (MD) simulations, we examine the role played by Al diffusion at the SLI interface in this phenomena and in the spreading of droplets. For Cu/Pb interfaces, earlier simulations predict a strong anisotropy in interfacial structure, with the (100) interface exhibiting surface alloying and the (111) showing a “pre-freezing” region, 2-3 lattice spacings thick, of crystalline Pb at the interface. Using an extensive series of MD simulations we show how this structural anisotropy contributes significantly to differences in the heterogeneous nucleation rates between these two interfaces. Finally, we examine the Al(s)/Ga(l) solid-liquid interface, an important material for the understanding of liquid-metal embrittlement, using both classical and ab-initio molecular-dynamics simulation.