New Insights into Dewetting of Cu Thin Films Deposited on Si.

Very thin metallic films are susceptible to dewetting upon thermal excursions, resulting in fragmentation and hence loss of structural integrity. Herein, 15 to 55 nm thick Cu films deposited on a Si substrate were isothermally annealed at 400 to 700 °C inside a scanning electron microscope operating in high-vacuum mode and the ensuing dewetting behavior was studied. The observations revealed that the induction time before the void nucleation varied with film thickness as per a power-law with an exponent of 4, and the activation energy for both the void nucleation and the growth was close to the activation energy for surface diffusion.

Interphase anisotropy effects on lamellar eutectics: a numerical study.

In directional solidification of binary eutectics, it is often observed that two-phase lamellar growth patterns grow tilted with respect to the direction z of the imposed temperature gradient. This crystallographic effect depends on the orientation of the two crystal phases α and β with respect to z. Recently, an approximate theory was formulated that predicts the lamellar tilt angle as a function of the anisotropy of the free energy of the solid(α)-solid(β) interphase boundary.

Grand-potential formulation for multicomponent phase transformations combined with thin-interface asymptotics of the double-obstacle potential.

In this paper, we describe the derivation of a model for the simulation of phase transformations in multicomponent real alloys starting from a grand-potential functional. We first point out the limitations of a phase-field model when evolution equations for the concentration and the phase-field variables are derived from a free energy functional. These limitations are mainly attributed to the contribution of the grand-chemical-potential excess to the interface energy.

Theoretical and numerical study of lamellar eutectic three-phase growth in ternary alloys.

We investigate lamellar three-phase patterns that form during the directional solidification of ternary eutectic alloys in thin samples. A distinctive feature of this system is that many different geometric arrangements of the three phases are possible, contrary to the widely studied two-phase patterns in binary eutectics. Here, we first analyze the case of stable lamellar coupled growth of a symmetric model ternary eutectic alloy, using a Jackson-Hunt-type calculation in thin film geometry, for arbitrary configurations, and derive expressions for the front undercooling as a function of velocity and spacing.