Modeling solid-state dewetting of a single-crystal binary alloy thin films

Abstract

Dewetting of a binary alloy thin film is studied using a continuum many-parameter model that accounts for the surface and bulk diffusion, the bulk phase separation, the surface segregation and the particles formation. Analytical solution is found for the quasistatic equilibrium concentration of a surface-segregated atomic species. This solution is factored into the nonlinear and coupled evolution PDEs for the bulk composition and surface morphology. Stability of a planar film surface with respect to small perturbations of the shape and composition is analyzed, revealing the dependence of the particles size on major physical parameters. Computations show various scenarios of the particles formation and the redistribution of the alloy components inside the particles and on their surface. In most situations, for the alloy film composed initially of 50% A and 50% B atoms, a core-shell particles are formed, and they are located atop a wetting layer that is modestly rich in the B phase. Then the particles shell is the nanometric segregated layer of the A phase, and the core is the alloy that is modestly rich in the A phase.

Analysis of Self-Organized Patterned Surface Oxide Spots on Ejected Spatter Produced during Laser Powder Bed Fusion

“…The shapes and configurations of the observed surface patterns are consistent with patterning and organization described by Turing and others [15][16][17][18][19][20][23][24][25][26][27] and supports the hypothesis that these particles formed from liquid generated during LPBF processing which had time to undergo organization into the observed surface configurations. While many of the mathematical descriptions of patterning and self-organization are based on biological processes, the theory and modeling of organization has expanded to describe processes ranging from earth sciences, semiconductors, thin films, nanotechnology and materials science.…”

“…While many of the mathematical descriptions of patterning and self-organization are based on biological processes, the theory and modeling of organization has expanded to describe processes ranging from earth sciences, semiconductors, thin films, nanotechnology and materials science. Pattern configuration is typically dependent on the relationship between the liquid species properties where modeling of applications have demonstrated features ranging from symmetrical and non-symmetrical stripes and spots to random features on curved, flat and irregular surfaces in a variety of systems and conditions [15][16][17][18][19][20][23][24][25][26][27].…”

“…3 and, in a second stage, oxidize in the low oxygen partial pressure environment of the PBF chamber to form glassy silicates. The mechanisms for ordering of the silicon into organized features arise through a variety of effects: instabilities due to gradients in surface tension, elasticity, or chemical reaction rates [20,[23][24][25][26][27]. A key avenue for future study would be investigate such properties as the coarsening dynamics or the response to perturbations of a smooth interface.…”

Solid-state dewetting on curved substrates

“…The dewetting of solid thin films deposited on substrates is similar to the dewetting of liquid films [25], and * Corresponding author: jiangwei1007@whu.edu.cn they share some common features, such as the moving contact line [26][27][28], Rayleigh instability [29][30][31], multiscale and multi-physics features [32][33][34][35]. However, they have many important major differences.…”

On a fourth order equation describing single-component film models

“…We here focus on the single-component film with uniform composition of the bulk and the surface. The study of this particular problem has been inspired by the paper proposed by M. Khenner [11]. In his work, M. Khenner developed a theoretical model which describes the redistribution of the alloy components in the bulk of the film and on its surface during the dewetting process.…”