Frontiers in Solidification: An MPMD Symposium Honoring Jonathan A. Dantzig: Modeling: From Atomistic to Meso- to Macro-scales
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS Functional Materials Division, TMS Light Metals Division, TMS Structural Materials Division, TMS: Aluminum Committee, TMS: Chemistry and Physics of Materials Committee, TMS: Process Technology and Modeling Committee, TMS: Solidification Committee
Program Organizers: Andre Phillion, McMaster University; Michel Rappaz, Ecole Polytechnique Fédérale De Lausanne; Melis Serefoglu, Marmara University; Damien Tourret, IMDEA Materials Institute
Tuesday 2:30 PM
March 21, 2023
Room: 28E
Location: SDCC
Session Chair: Alain Karma, Northeastern University; Ingo Steinbach, Ruhr-University Bochum
2:30 PM Invited
Dealloying of Metals in Molten Salts – From Atomistic to Mesoscale Simulations: Nathan Bieberdorf1; Nick Winner1; Luke Langford1; Andrea Hwang1; Raluca Scarlat1; Laurent Capolungo2; Mark Asta1; 1University of California, Berkeley; 2Los Alamos National Laboratory
Dealloying is a well-studied process in alloys exposed to liquids that selectively dissovle one element over another. The phenomenon can lead to formation of complex interconnected dealloyed patterns useful for the development of nanoporous materials. This talk focuses on the analogous process of dealloying in the context of molten salt corrosion of structural metals, a subject of current interest for research related to molten-salt nuclear reactors. We present results of atomistic simulations of bulk and interfacial systems, as well as phase field modeling using methods based on previously published models for liquid-metal dealloying, to investigate phenomena related to molten salt corrosion. Specific topics include the nature of the solvation of corrosion products in molten salts, the structure and kinetics of metal/salt interfaces, and the role of grain boundaries, interfacial transport processes and triple junctions on dealloying rates and morphologies. Research supported by the DOE-BES FUTURE EFRC.
3:00 PM Invited
Development of Phase Field Type Theories for Modelling Solidification Across Multiple Length Scales: Nikolas Provatas1; 1McGill University
We review theoretical and numerical advances that made phase field modelling practical for studying solidification across multiple length scales. Examples are recalled, from early applications to more recent applications in rapid solidification in polycrystalline systems. We then fast-forward to the evolution of the phase field into a periodic entity and the introduction of phase field crystal (PFC) models, which couple diffusion-limited phase transformations to grain boundaries, dislocations, and elasto-plasticity. We review PFC applications to dislocation flow, defect-assisted nucleation, and complex non-metallic symmetries. We end with a latest direction in PFC modelling that affords control of the full phase space of solid, liquid, and vapor phases and allows for pressure-control, density-induced shrinkage, and void formation phenomena. We highlight recent studies of rapid solidification of thin-film Al and Al-Cu that reproduce experimentally observed orientation gradients within crystallizing grains and provide a causal connection between defect and void formation and orientation gradients.
3:30 PM Invited
Molecular Dynamics Simulations of Solid-liquid Interfaces: A Progress Report: Jeffrey Hoyt1; 1McMaster University
The capillary fluctuation method (CFM) has emerged as an effective atomistic simulation tool to investigate thermodynamic properties of solid-liquid interfaces. In this work the application of the CFM to binary alloys, and in particular the temperature dependence of the excess interfacial free energy, is discussed. In most alloys the interfacial energy decreases with decreasing temperature, which is consistent with Spaepen’s negative entropy model for pure systems. However, in Cu-Zr and Al-Sm, both glass forming alloys, the interfacial energy rises dramatically with a decrease of temperature. A possible explanation for the unusual temperature dependence in terms of the atomistic structure of the solid-liquid interface will be presented. In addition, the link between the interface structure and the unusual temperature dependence will be discussed using Gibbsian excess interfacial quantities.
4:00 PM Break
4:20 PM Cancelled
Growth and Melting of Crystals: Molecular Dynamics versus Phase Field Modeling: Peter Galenko1; 1Friedrich Schiller University Jena
A kinetic phase field model for small and large driving forces on solidification and melting of a pure metal or binary alloy is formulated. A traveling wave solution of the phase field equation predicts the non-linear behavior in the velocity of the fast and slow crystal-liquid interface. This non-linearity has the dependence of velocity with saturation or exhibiting the velocity with a maximum at a fixed undercooling/superheating. The predicted velocity is compared with the molecular dynamics simulation data for elemental and binary systems. A crucial role of local non-equilibrium in the form of relaxation of gradient flow in the quantitative description of the crystal growth kinetics is shown. The described kinetic effects are included in the dendrite growth model whose predictions are compared with experimental data on the rapid solidification of binary alloys.
4:40 PM
An Integrated Machine Learning and Phase-field Approach for Accurate Prediction of Dendritic Arm Spacing: Sepideh Kavousi1; Mohsen Asle Zaeem1; 1Colorado School of Mines
This study describes the exploration of data science techniques to predict primary dendritic arm spacing (PDAS) for solidification of different material systems. The theoretical models, which relate the PDAS to the material properties and solidification conditions—pulling velocity and temperature gradient—do not match the relationships obtained from experimental and computational studies. We present a machine learning model for predicting PDAS via performing atomistic-informed phase field modeling of solidification for various compositions of Al-Cu, Ti-Ni, and Mg-Al alloys. A three-layer hidden feedforward artificial neural network (ANN) model is developed and trained to mimic the arm spacing associated with the training data set. To produce a new global relation for PDAS, we used material systems with different crystal structures (FCC, BCC, and HCP) and accounted for slow, moderate, and rapid solidification rates.
5:00 PM
About the Solidification Path in Multicomponent Alloys: Multiphase-field Simulations versus Gulliver-Scheil: Markus Apel1; Bernd Böttger1; Bei Zhou1; 1Access e.V.
The solidification path, in particular the later stage, is an important attribute for the processing of multicomponent alloys, e.g. a large solidification interval may promote hot tearing. The standard approach to compute fraction solid as function of temperature is still the Gulliver-Scheil (GS) model. Input for the GS model are solely thermodynamic state variables and GS leads to a unique solution independent on cooling rate and solidification morphology. In contrast, phase-field models explicitly considers diffusion, both in the liquid and solid state.We compare results from multiphase-field simulations (MPF) for multicomponent alloys with GS-calculations and discuss the impact of cooling rate and solidification morphology, the impact of nucleation undercooling and density of secondary phases, and potential artifacts due to the diffuse PF interface thickness. In consequence, GS and MPF will lead to different estimations for the hot crack susceptibility based on e.g. critical temperature interval criteria or the Kou-criterion.
5:20 PM
New Insights in Controlling Freckle Defect Formation Using Magnetic Fields: Xianqiang Fan1; Natalia Shevchenko2; Catherine Tonry3; Samuel Clark4; Robert Atwood5; Sven Eckert2; Koulis Pericleous3; Peter Lee1; Andrew Kao3; 1UCL; 2HZDR; 3University of Greenwich; 4Argonne National Lab; 5Diamond Light Source
Static magnetic fields have been shown to have a significant effect on channel formation in the GaIn freckle defect forming alloy. Inter-dendritic convective solute transport driven by the Thermoelectric Magnetoydrodynamics (TEMHD) phenomena leads to repositioning of the channel, preferential growth of secondary arms, plume migration and complex grain boundary interactions. This paper focuses on a secondary TEMHD mechanism that is generated by larger scale thermoelectric currents that circulate between the liquid and the entire mushy zone. This secondary mechanism is strongly dependent on the thermal profile and this leads to further modification of the bulk flow and ultimately plume migration. This mechanism has been observed by Xray synchrotron experiments and predicted by TESA (ThermoElectric Solidification Algorithm), a parallel Cellular Automata Lattice Boltzmann based numerical model, providing new insights into the intimate coupling between thermal solidification conditions and the effect of the magnetic field.
5:40 PM
Modelling of Interface Evolution in Advanced Welding (Mintweld): Hongbiao Dong1; 1University of Leicester
In this talk, I will present our work in an EU FP7 project (MintWeld) which I collaborated with Jon. In the project, we established a multi-scale, multi-physics modelling frame work for arc welding. An integrated suite of modelling software has been developed and validated, able to describe the key phenomena of the welding process at all relevant length scales, with a special emphasis on in-situ measurement of internal flow in melt pool during arc welding, the solid-liquid interface evolution, including the description of macro-scale mass flow and thermal profile in weld pool, meso-scale solid/liquid interface movements during melting and solidification of weld joints, micro/nano-scale grain boundary and morphology evolution in the solidified joints, mechanical integrity, and service life of the welded products. Acknowledgments: Thisresearch work is supported by the European Commission as part of the FP7 programme, as the project, Modelling of Interface Evolution in Advanced Welding; contract number no. NMP3-SL-2009-229108.