Wetting and capillarity driven grain rearrangement and microstructure evolution during liquid phase sintering: Solubility and particle size effects
Glass, Ceramics and Derived Composites
Final Report Abstract
The main achievements of the project are listed below. • A model was developed to predict the morphology of liquid bridges connecting two spherical solid grains. The theory is shown to be qualitatively in line with simulation results for various liquid volume fractions and contact angles. • It has been shown that curvature-induced stresses enhance the initial sintering stage (solid-solid contact) for sub-micrometer grain sizes. The effect becomes stronger for smaller grains. • The role of coalescence phenomenon and the ways to control it have been elucidated. • Basic questions regarding the coupling between fluid flow and phase field dynamics have been addressed from a theoretical perspective. • Morphology of multiple grain structures has been investigated via numerical simulations after a thorough validation of the model. • The model has been applied to a soft-hard powder mixture using cobalt-tungsten showing that it is capable of predicting porous microstructures for different initial particle configuration. • All the new routines developed during this project are implemented in OpenPhase-software package and is made publicly available. The established work and the developed simulation package can serve as a starting point for future studies of liquid phase sintering with focus on effects arising from properties of individual powder components, their mass ratio, size distribution and variation of process parameters.
Publications
- "Multi-phase-field method for surface tension induced elasticity", Phys. Rev. B 97, 035410 (2018)
R. Schiedung, I. Steinbach, F. Varnik
(See online at https://doi.org/10.1103/PhysRevB.97.035410) - "Controlling bubble coalescence in metallic foams: A simple phase fieldbased approach", Computational Materials Science 173, 109437 (2020)
S. Vakili, I. Steinbach, F. Varnik
(See online at https://doi.org/10.1016/j.commatsci.2019.109437) - "Diffuse interface models of solidification with convection: The choice of a finite interface thickness", Eur. Phys. J. Special Topics 229, 447 (2020)
A. Subhedar, P. Galenko, F. Varnik
(See online at https://doi.org/10.1140/epjst/e2019-900099-5) - "Simulation of Capillary-Driven Kinetics with Multi-Phase- Field and Lattice-Boltzmann Method", Modelling Simul. Mater. Sci. Eng. 28, 065008 (2020)
R. Schiedung, M. Tegeler, D. Medvedev, F. Varnik
(See online at https://doi.org/10.1088/1361-651X/ab9bb3) - "Thin interface limit of the double sided phase field model with convection", Philosophical Transactions A 378, 20190540 (2020)
A. Subhedar, P. Galenko, F. Varnik
(See online at https://doi.org/10.1098/rsta.2019.0540)
