TY - JOUR
T1 - Capillary effects on curved solid–liquid interfaces
T2 - An overview
AU - Glicksman, Martin E.
AU - Ankit, Kumar
AU - Wu, Peichen
N1 - Funding Information:
The authors are honored to contribute an account of our collective research efforts on capillary effects at steady-state crystal-melt interfaces, and to add to this journal's timely Festschrift, honoring the lifetime of work by Dr. Alexander A. Chernov. Dr. Chernov, through his long, productive, and distinguished career in the fields of crystallography and crystal growth science has, to his credit, many important scientific accomplishments. His research, books, professional expertise, and extraordinary wealth of scientific understanding have all profoundly advanced the field of crystallography and improved our fundamental understanding of crystal growth phenomena and its practice. Author Glicksman met and befriended Dr. Chernov when they attended the IVth All Union Conference on Crystal Growth, Tsakhadzor, Armenian SSR, in 1972. At that meeting Dr. Chernov was serving as laboratory director of the USSR's Institute of Crystallography, Russian Academy of Science, Moscow, whereas Glicksman represented the Naval Research Laboratory, Washington, DC, as Head of NRL's Transformations and Kinetics Branch, Metallurgy Division. Over two decades later, then as Director of Microgravity Research Programs, Universities Space Research Association (USRA), Glicksman assisted in Dr. Chernov's becoming a USRA Visiting Scientist at NASA's Marshall Space Flight Center, Huntsville, Alabama. “Our contacts and discussions over the intervening years when Sasha Chernov was at NASA Marshall, and later at the Energy Department's LLNL, were always warm, productive, and excellent. “He's been a life-long friend”, said Glicksman. We all wish Dr. Chernov continued health and productivity. We also acknowledge Dr. Kalpana Chawla, our NASA astronaut and mission specialist, who on her first space-flight helped us operate the IDGE-3 hardware in 1997. Sadly, just 5 years later, on her second venture into space, Dr. Chawla was killed while returning to Earth on Shuttle Columbia, flight STS-107, when its crew of seven were lost in a devastating re-entry accident. We dedicate this overview to her memory and faithful public service, and to its contribution to our present research. This research was funded through the National Aeronautics and Space Administration, USA's Physical Science Informatics (NASA-PSI) Program, via contract number 80NSSC18K1440. In addition, MEG thanks the Allen S. Henry Chair fund at Florida Institute of Technology, USA, for its partial support of this research.
Funding Information:
This research was funded through the National Aeronautics and Space Administration, USA ’s Physical Science Informatics (NASA-PSI) Program, via contract number 80NSSC18K1440 . In addition, MEG thanks the Allen S. Henry Chair fund at Florida Institute of Technology, USA , for its partial support of this research.
Publisher Copyright:
© 2022 Elsevier B.V.
PY - 2023/1/15
Y1 - 2023/1/15
N2 - This overview begins with observations of capillary-mediated effects on crystal-melt interfaces in microgravity and attempts to interpret them using the LeChâtelier–Braun effect and Kelvin's equation—both local equilibrium requirements applicable at curved interfaces. Numerical studies of interfacial kinetics followed, using Greens function distributions that simulated evolving sharp solid–liquid interfaces undergoing pattern formation. Those methods exposed a need for more incisive steady-state techniques. Grain boundary grooves were used as constrained, stationary, microstructures. Their steady-state profiles derive from variational calculus and were analyzed for their imputed Gibbs–Thomson thermopotentials for comparative thermodynamic studies. Variational profiles, however, have unrealistic zero-thickness transitions between phases, and thus lack fluxes of energy or solute that occur on real interfaces. The exact formulation of variational profiles, however, advantageously supports field-theoretic calculations of their first-order formation free energy, thermodynamic stability, capillary-mediated chemical potentials, interfacial gradients and scalar divergences. These linked fields all depend on an interface's curvature distribution, i.e., its geometry, but others, for example tangential fluxes of energy and solute, also depend on interface thickness and structure, i.e., thermodynamics. We comparatively analyzed capillary-mediated fields up to 4th-order, including the surface Laplacian of a profile's chemical potential. This Laplacian is proportional to scaled divergences of fluxes that appear on counterpart real or simulated microstructures with congruent shapes. Divergent energy fluxes manifest as cooling distributions, which cause depression of the thermochemical potential measured along diffuse-interfaces simulated with phase-field. Cooling distributions are visualized to explain qualitative and quantitative features of a microstructure's steady-state thermal maps. Evidence is included of how thickness and shape of crystal-melt interfaces co-determine whether, and to what extent, interfacial transport occurs. Understanding the origin and actions of interfacial capillary fields might offer improved control of microstructure at mesoscopic levels, accessible with these deterministic fields through physical and chemical means.
AB - This overview begins with observations of capillary-mediated effects on crystal-melt interfaces in microgravity and attempts to interpret them using the LeChâtelier–Braun effect and Kelvin's equation—both local equilibrium requirements applicable at curved interfaces. Numerical studies of interfacial kinetics followed, using Greens function distributions that simulated evolving sharp solid–liquid interfaces undergoing pattern formation. Those methods exposed a need for more incisive steady-state techniques. Grain boundary grooves were used as constrained, stationary, microstructures. Their steady-state profiles derive from variational calculus and were analyzed for their imputed Gibbs–Thomson thermopotentials for comparative thermodynamic studies. Variational profiles, however, have unrealistic zero-thickness transitions between phases, and thus lack fluxes of energy or solute that occur on real interfaces. The exact formulation of variational profiles, however, advantageously supports field-theoretic calculations of their first-order formation free energy, thermodynamic stability, capillary-mediated chemical potentials, interfacial gradients and scalar divergences. These linked fields all depend on an interface's curvature distribution, i.e., its geometry, but others, for example tangential fluxes of energy and solute, also depend on interface thickness and structure, i.e., thermodynamics. We comparatively analyzed capillary-mediated fields up to 4th-order, including the surface Laplacian of a profile's chemical potential. This Laplacian is proportional to scaled divergences of fluxes that appear on counterpart real or simulated microstructures with congruent shapes. Divergent energy fluxes manifest as cooling distributions, which cause depression of the thermochemical potential measured along diffuse-interfaces simulated with phase-field. Cooling distributions are visualized to explain qualitative and quantitative features of a microstructure's steady-state thermal maps. Evidence is included of how thickness and shape of crystal-melt interfaces co-determine whether, and to what extent, interfacial transport occurs. Understanding the origin and actions of interfacial capillary fields might offer improved control of microstructure at mesoscopic levels, accessible with these deterministic fields through physical and chemical means.
KW - A1. Capillarity
KW - A1. Grain boundary grooves
KW - A1. Phase-field modeling
KW - A1. Solidification
KW - A1. Solid–liquid interfaces
KW - A1. Surface laplacian
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U2 - 10.1016/j.jcrysgro.2022.126871
DO - 10.1016/j.jcrysgro.2022.126871
M3 - Article
AN - SCOPUS:85142152604
SN - 0022-0248
VL - 602
JO - Journal of Crystal Growth
JF - Journal of Crystal Growth
M1 - 126871
ER -