Periodic Grain Boundary Grooves: Analytic Model, Formation Energies, and Phase-Field Comparison

Martin E. Glicksman, Peichen Wu, Kumar Ankit

Research output: Contribution to journalArticlepeer-review

Abstract

Analytic profiles for periodic grain boundary grooves (PGBGs) were determined from variational theory. Variational profiles represent stationary solid-liquid profiles with abrupt, zero-thickness, transitions between adjoining phases. Variational PGBGs consequently lack tangential interfacial fluxes, the existence of which requires more realistic (non-zero) interfacial thicknesses that allow energy and solute transport. Variational profiles, however, permit field-theoretic calculations of their scaled formation free energy and thermodynamic stability, capillary-mediated chemical potentials, and their associated vector gradient distributions, all of which depend on a profile’s geometry, not its thickness. Despite the fact that variational profiles are denied interface fluxes, one may, nevertheless, impute shape-dependent interface transport in the form of a profile’s surface Laplacian of its presumptive chemical potential distribution due to capillarity. We compare variational surface Laplacians with residuals of the thermochemical potential measured along counterpart diffuse-interface PGBGs, simulated via phase-field with metrically-proportional profiles. Fundamentally, it is the thickness of a microstructure’s interfaces and its shape that co-determine whether, and to what extent, gradients of the chemical potential excite fluxes that transport energy and/or solute. PGBGs, both variational and simulated, greatly expand the limited universe of solid-liquid microstructures suitable for steady-state thermodynamic analysis. Understanding the origin and action of these capillary-mediated interfacial fields opens a pathway for estimating and, eventually, measuring how solid-liquid interface thickness modifies the transport of energy and solute during solidification and crystal growth, and influences microstructure.

Original languageEnglish (US)
JournalJournal of Phase Equilibria and Diffusion
DOIs
StateAccepted/In press - 2022

Keywords

  • capillarity
  • grain boundary grooves
  • interface stability
  • phase-field modeling
  • solid-liquid interfaces
  • surface Laplacian
  • surface thermodynamics

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Metals and Alloys
  • Materials Chemistry

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