Frontiers in Solidification Science VIII: Faceted Growth / Solid-Liquid Interfaces
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Chemistry and Physics of Materials Committee, TMS: Phase Transformations Committee, TMS: Solidification Committee, TMS: Computational Materials Science and Engineering Committee
Program Organizers: Damien Tourret, IMDEA Materials Institute; Amy Clarke, Los Alamos National Laboratory; Ulrike Hecht, Access e.V.; Nana Ofori-Opoku, Canadian Nuclear Laboratories; Melis Serefoglu, Marmara University; Tiberiu Stan, Asml
Tuesday 2:00 PM
March 16, 2021
Room: RM 56
Location: TMS2021 Virtual
Session Chair: Mohsen Asle Zaeem, Colorado School of Mines; Damien Tourret, IMDEA Materials; Alain Karma, Northeastern University; Nana Ofori-Opoku, Canadian Nuclear Laboratories
2:00 PM Invited
3D Phase-field Simulations of Pattern Formation during Freeze Casting: Kaihua Ji1; Kaiyang Yin1; Louise Strutzenberg2; Rohit Trivedi3; Ulrike Wegst1; Alain Karma1; 1Northeastern University; 2NASA Marshall Space Flight Center; 3Iowa State University
We present the results of a combined experimental and phase-field modeling study of pattern formation during freeze casting. Those studies use unidirectional freezing of simple binary liquid mixtures of water and sugars (sucrose and trehalose) in a temperature gradient, which suffice to produce hierarchical templated structures similar to those observed in more complex multi-component freeze-cast systems including lamellae, undulated ridges, and more exotic “jellyfish-like” substructures. Multiscale 3D phase-field simulations reproduce remarkably well those structures quantitatively and identify key properties of the ice-water interface that control their formation. They further reveal that lamellae form as a result of a novel symmetry-breaking secondary instability of partially faceted cellular structures and pinpoint additional secondary instability mechanisms giving rise to smaller-scale substructures.
2:30 PM
Experimental Observations of Mechanisms of Pattern Formation during Freeze Casting: Kaiyang Yin1; Kaihua Ji1; Louise Strutzenberg2; Rohit Trivedi3; Alain Karma1; Ulrike G.K. Wegst1; 1Northeastern University; 2NASA Marshall Space Flight Center; 3Iowa State University
Empirically, many different materials compositions have been freeze cast over the years. Few have been analyzed to better understand the mechanisms by which the ice crystal growth drives structure formation, particularly the substructures on the cell walls. Collating substructural features, for example, ridges, bridges, and “jellyfish"-like substructures, found on the cell walls of freeze-cast ceramics (platelets versus particles), fibrillated biopolymers (collagen, nanocellulose), and "smooth" biopolymers (chitosan, trehalose), we capture the ice crystal growth process and analyze it both in situ in 2D and "post-mortem" in 3D to gain insights into anisotropic ice crystal growth and other self-assembly mechanisms. Combining these experimental observations with 3D Phase-field simulations of structure formation in ice-templated materials, detailed in a companion presentation, it becomes possible to gain fundamental science insights and to obtain the desired structure-property-processing correlations not only at the more traditional macroscopic, but also at the meso- and microscopic scales.
2:50 PM Invited
Combination of X-ray Topography and Radiography for In Situ and Time Resolved Investigation of the Solidification of Silicon: Hadjer Ouaddah1; Gabrielle Regula1; Guillaume Reinhart1; Nathalie Mangelinck-Noel1; 1IM2NP CNRS UMR 7334, Aix Marseille University
Aiming to the production of low cost and high efficiency solar cells based on silicon material, all processes either innovative or conventional face challenges linked to the grain structure and crystalline defects left during the solidification step. Our contribution consists in conducting in situ and time-resolved investigations on the fundamental solidification mechanisms in a unique device named GaTSBI (Growth at high Temperature observed by X-ray Synchrotron Beam Imaging). Two imaging techniques using X-ray synchrotron radiation are combined during solidification: X-ray radiography and Bragg diffraction (topography). X-ray radiography brings information on the morphology and kinetics of the solid/liquid (S/L) interface. X-ray Bragg diffraction gives complementary information about misorientations, structural defect formation and the local level of deformation of the crystal structure.During the presentation, the dynamics of twinning, grain competition and the origin of dislocations as well as their interaction with grain boundaries during solidification will be presented.
3:20 PM
Facetted Growth in Isothermal Solidification of Silicon: 3D Phase-field Simulations of Growth and Equilibrium Shapes
: Ahmed Kaci Boukellal1; Ahmed Kerim Sidi Elvalli2; Jean-Marc Debierre3; 1Aix-Marseille University (IM2NP) and IMDEA Materials; 2Aix-Marseille University (IM2NP) and Spintec; 3Aix-Marseille University (IM2NP)
Phase-field simulations of facetted growth require special attention to the representation of strongly anisotropic properties of solid-liquid interfaces. The present work deals with the numerical study of isothermal solidification of silicon (Si) using the thin interface phase-field model developed by Karma et al. (Phys. Rev. E 57, 4323, 1998). Based on physical considerations and on the experimental results of Yang et al. (Prog. Photovolt: Res. Appl., 22, 574-580, 2014), we propose analytical anisotropy functions of the interface energy and attachment kinetics. These functions aim to trigger {111} facets formation. We find that both functions are essential to reproduce the early growth shapes while only that of the surface energy is involved at equilibrium (Boukellal et al., J. Cryst. Growth, 522, 37-44, 2019).
3:40 PM Invited
Bridging Multiscale Models for Predicting Nano and Microstructures in Rapid Solidification of Metals and Alloys: Mohsen Asle Zaeem1; 1Colorado School of Mines
A transferable multiscale modeling framework will be presented to quantitatively study rapid solidification in different metals and alloys accounting for the multi length and time scale characteristics of solidification. An algorithm for developing accurate interatomic potentials capable of predicting low and high temperature properties and phases of several metals and alloys will be presented. The interatomic potentials are developed based on the semi-empirical modified embedded atom method using low and high temperature data from electronic structure calculations and experiments. By utilizing large scale molecular dynamics (MD) simulations, the capabilities and transferability of these potentials are tested in study of the homogeneous and heterogeneous nucleation and phase formation processes during rapid solidification of different metals and alloys. Directly utilizing MD data, a quantitative phase-field modeling framework is developed to accurately predict the solidification microstructures and predict solute trapping and primary dendrite arm spacing in a wide range of solidification rates.
4:10 PM
A Method of Estimation of Solid-liquid Interface Anisotropy Based on Machine Learning Combined with Phase-field Simulations: Geunwoo Kim1; Tomohiro Takaki2; Yasushi Shibuta3; Munekazu Ohno1; 1Hokkaido University; 2Kyoto Institute of Technology; 3The University of Tokyo
Anisotropy parameters of solid-liquid interface energy are important parameters that determine the preferred growth direction of dendrites in alloy solidification. It is important for description of microstructural processes to measure or estimate anisotropy parameters including its concentration-dependences with accuracy. However, the experimental measurement or estimation is not straightforward. In this study, we propose a method for estimating anisotropy parameters in fcc alloy, ε1 and ε2, by combining phase-field simulations with machine learning. The phase-field simulations for solidification microstructures in fcc model alloy with different sets of ε1 and ε2 were carried out and various microstructure thus simulated were characterized by the distribution of local curvedness (C) and shape indicator (S) of solid-liquid interface. Datasets of (ε1,ε2) and corresponding (C,S) distribution were trained by deep neural networks. This method allows determination of anisotropy parameters from the given (C,S) distribution accurately.
4:30 PM
Structural Changes during Crystallization and Vitrification of Dilute FCC-based Binary Alloys: Deep Choudhuri1; Bhaskar Majumdar1; 1New Mexico Institute of Mining and Technology
Structural changes during crystallization and vitrification in dilute face-centered-cubic (FCC) alloys was investigated using model Al-Sm alloys. Molecular dynamics simulations were performed to study the solidification behavior of Al-1at.%Sm and Al-5at.%Sm at 10^10, 10^11 and 10^12 K/s cooling rates. Two structural features were identified from these simulations. In case of Al-1at.%Sm, we learn that, near the melting point, liquid phase manifested pockets of unique transitional structures comprising triangular arrangements in near-parallel layers that encapsulated a FCC-HCP coordinated core. We defined such a structure as the pre-critical nucleus, which is contained within an otherwise predominantly uncoordinated amorphous liquid phase. However, within the range of cooling rates employed, Al-5at.%Sm manifested only amorphous structure after solidification. The liquid structure in the transitional state contained temperature dependent icosahedron clusters that manifested as double-peak in the radial distribution function. Near the Tg Al-5at.%Sm achieves additional local ordering via the formation of inter-penetrating icosahedral frameworks.
4:50 PM
Unraveling the Effect of Solid-liquid Interfacial Anisotropy on Pattern Formation in Rapid Directional Solidification of Binary Alloys: Ghavam Azizi1; Mohsen Asle Zaeem1; 1Colorado School of Mines
Intrinsic properties of the solid-liquid interface play a key role on determination of morphological pattern in alloys solidification. Using molecular dynamic simulation, the interfacial energy and its anisotropy are determined for different Al-Cu alloys. The effect of solid-liquid interface properties on interface stability, solidification pattern, segregation of solute atoms, and final phase fractions are investigated using phase-field modeling. While at low anisotropy values cellular pattern is dominant, by increasing anisotropy the interface becomes less stable and dendritic pattern forms. Furthermore, by increasing anisotropy value the primary and secondary arm spacing decreases, the growth velocity of dendrites increases, and less Al2Cu (θ-phase) forms in final structure. It is also shown that the effect of interface anisotropy is more pronounced at higher cooling rates.