Computational Thermodynamics and Kinetics: On-Demand Poster Session
Sponsored by: TMS Functional Materials Division, TMS Materials Processing and Manufacturing Division, TMS Structural Materials Division, TMS: Chemistry and Physics of Materials Committee
Program Organizers: Vahid Attari, Texas A&M University; Sara Kadkhodaei, University of Illinois Chicago; Eva Zarkadoula, Oak Ridge National Laboratory; Damien Tourret, IMDEA Materials Institute; James Morris, Ames Laboratory

Monday 8:00 AM
March 14, 2022
Room: Physical Metallurgy
Location: On-Demand Poster Hall

3D-reconstruction of Sectioning Nephograms Based on Simulated Results: Xiao Han1; 1Beijing Jiaotong University
    Modeling and simulation usually requires the integration of more and more software, such as Integrated computed materials engineering (ICME). However, it is difficult due to the unavailability of the original model or the simulated result data. In this paper, a method is proposed to realize the acquisition of original model and simulated result data based on a series of slice images of simulated results which can be obtained in the post processing interface of software. The slice images can be transferred into 3D model with mapping of pixels to meshes and the color of pixels can be mapped into the simulated results of meshes. The model and data can be further analyzed and integrated into other software as initial condition for new simulation. Case studies of the simulation of castings are provided. The sectioning videos of simulated temperature results during solidification are transferred into 3D casting and mold FDM model and simulated results.

Effect of Alloying Elements on the Stability of (Cr,Zr) Intermetallic Phases: Theresa Davey1; Ying Chen1; 1Tohoku University
     The application of chromium-based coatings to zirconium alloy clad nuclear fuels may improve safety margins in loss-of-coolant accidents. When exposed to steam in a high-temperature accident scenario, a Cr2O3 scale will form on the surface, preventing catastrophic oxidation of the zirconium alloy. An intermetallic layer of ZrCr2 will form between the Cr-based coating and the Zr-based alloy, and diffusion of Cr, Zr, and other alloying elements will occur in each of the metallic layers. The stability of the ZrCr2 Laves phases and the bcc and hcp solid solution phases is explored using first-principles calculation. Special Quasirandom Structures (SQS) are used to represent chemical mixtures in the bcc and hcp solid solutions and antisite mixing in the Laves phases. The calculated energies are incorporated into a Calphad-type thermodynamic database. The effect of alloying elements (e.g. Fe, Ni, Sn, Nb) on the stability and stoichiometry range of each phase is also considered.

Thermodynamic Database of Sm-Ti Binary System from First-principles Calculations: Arkapol Saengdeejing1; Ying Chen1; 1Tohoku University
    SmFe12-based compounds have been considered as a potential candidate that achieves on par or better performance than current commercially available Nd2Fe14B-based permanent magnet. Towards the instability of SmFe12, Ti is taken as one of the best stabilizing elements for SmFe12. As one of the sub-binary systems of Sm-Fe-Ti-X multinary, thermodynamic data of Sm-Ti is necessary, but there is no any data available either experimentally or computationally which makes difficult to explore the Sm-Fe-Ti-X multinary system through the CALPHAD approach. Employing first-principles calculations, we calculated the electronic structures at zero K and the lattice vibration effect of ordered phases. Combing with the cluster expansion method (CEM) and special quasirandom structures (SQS) we obtained the finite temperature Gibbs energy of disordered fcc, bcc, hcp and rhombohedral structures. The DFT-based thermodynamic database of Sm-Ti has been constructed and the first Sm-Ti phase diagram has been calculated accordingly.

Simulation and Experimental Characterization of Intragranular Ferrite Nucleation on Deformation Induced (Ti,V)(C,N) Precipitates in Microalloyed Steel: Evelyn Sobotka1; Johannes Kreyca2; Nora Fuchs1; Tomasz Wojcik1; Erwin Povoden-Karadeniz1; 1Christian Doppler Laboratory for Interfaces and Precipitation Engineering (CDL-IPE), Institute of Materials Science and Technology, TU Wien, Vienna, Austria; 2voestalpine Forschungsservicegesellschaft Donawitz GmbH
    Predictive thermokinetic simulations of intragranular ferrite nucleation on (Ti,V)(C,N) MX precipitates are expected to support the process development and cost savings of technological steel production. In this work, the role of microalloying elements on ferrite formation is investigated experimentally as well as by computational simulation. During thermo-mechanical treatments of microalloyed steels, deformation induced MX carbonitrides provide potential pre-nuclei for intragranular ferrite formation. Heat treatments and isothermal single-hit compression tests are performed on a Gleeble 3800 thermo-mechanical simulator to investigate the ferrite nucleation processes and microstructure evolution of a Ti, Nb, and V microalloyed steel grade. For in-situ observations, high temperature laser scanning confocal microscopy (HT-LSCM) is used. The nanoscale examination and chemical analysis of the phases is carried out by transmission electron microscopy (TEM). The experimental data serves as validation base of the on-particle nucleation model used for the precipitation of ferrite on the surface of MX carbonitrides.

Evaluation of Semi-solid Shear Deformation Behavior Using the Multi-phase-field Lattice Boltzmann Method: Namito Yamanaka1; Shinji Sakane1; Tomohiro Takaki1; 1Kyoto Institute Of Technology
    In casting processes, semi-solid deformation causes serious solidification defects, such as macrosegregation. To control the solidification defects, it is crucial to elucidate the mechanism of semi-solid deformation. Thus, modeling and simulation studies are indispensable for a better understanding of the semi-solid deformation. However, the semi-solid deformation is a significantly complicated multi physics problem that includes solidification, liquid flow, solid motion, solid-solid interaction, among other aspects. In our previous study, we constructed the multi-phase-field lattice Boltzmann (MPF-LB) model, which can simulate the growth of multiple dendrites with motion, liquid flow, collision, and grain growth, to express the formation process of equiaxed solidification structures [Comput. Mater. Sci., 197 (2021) 110658]. In this study, we investigate the two-dimensional semi-solid shear deformation using the MPF-LB model, where several parameters such as the solid fraction, grain size, and grain morphology are systematically changed.

Development of a Twin Experiment-validated Data Assimilation System for Dendrite Growth with Melt Convection Using Phase-field Lattice Boltzmann Method: Ayano Yamamura1; Shinji Sakane1; Munekazu Ohno2; Tomohiro Takaki1; 1Kyoto Institute of Technology; 2Hokkaido University
    Predicting the formation process of equiaxial structures accurately is critical for macrosegregation control in alloy casting. However, the equiaxial structure formation is poorly understood because it involves the motion of equiaxial crystals in the liquid phase. Recently, high-performance computing using phase-field lattice Boltzmann model and time-resolved X-ray tomography have been used to elucidate the equiaxial structure formation process. However, even with these state-of-the-art technologies, major issues such as the lack of material properties for simulations and spatiotemporal resolution in experiments persist. The purpose of this study is to combine experimental observation and simulation through data assimilation to develop a highly accurate prediction method for the formation process of an equiaxial structure. As a first step, a data assimilation system for dendrite growth with melt convection of a binary alloy is developed and validated using twin experiments.

Investigation of Phase-field Data Assimilation System Using In-situ Observation Results Obtained during Dendrite Growth in Thin Films: Yuki Imai1; Tomohiro Takaki1; Shinji Sakane1; Munekazu Ohno2; Hideyuki Yasuda3; 1Kyoto Institute of Technology; 2Hokkaido University; 3Kyoto University
    The phase-field method has been used extensively as it is a powerful numerical model that can predict dendrite growth during alloy solidification. However, this method possesses a significant disadvantage in that the material properties, such as the interface energy and its anisotropy, which are required for the phase-field simulation, have not been sufficiently determined. With the recent development of numerical techniques for the modelling of dendrite growth, it has now become possible to perform simulations at the same scale as in in-situ X-ray observation. In this study, we investigated the phase-field data assimilation system, employing which multiple phase-field simulations were performed simultaneously on the basis of the Bayesian inference using results obtained via in-situ X-ray observations. During the simulations, the unknown parameters were expected to gradually approach their true values. We used the in-situ observation results obtained during the directional solidification of Fe-Si in thin films as the observation data.

Multiphysics Modelling of Additively Manufactured Cellular Structures Using Selective Laser Melting: Mahmoud Elsadek1; Tarek Hatem1; 1The British University in Egypt
     Cellular structures are characterized by the large percentage of porosity and therefore large surface area. Therefore, they are extensively used as catalysts and filters and biological interfaces. Besides, they provide high stiffness-to-weight ratio, a high energy absorption, and low heat conductivity with smart geometrical orientations.In this work, a multi-physics model is developed starting from the thermodynamics analysis using Finite Element Method (FEM) and Computer Coupling of Phase Diagrams and Thermochemistry (CALPHAD) approach to predict then microstructure features. The proposed approach is applied for both cellular and bulk high-strength stainless steel alloy 17-4PH (Precipitation Hardening) structures to investigate the thermodynamics and kinetics of the transformation and its impact on the resulting microstructure.

A Tailor-made Experimental Setup for Thermogravimetric Analysis of the Hydrogen- and Carbon Monoxide- based Reduction of Iron (III) Oxide (Fe2O3) and Zinc Ferrite (ZnOFe2O3): Ulrich Brandner1; Juergen Antrekowitsch1; Felix Hoffelner1; Manuel Leuchtenmueller1; 1Montanuniversitaet Leoben
    Electric arc furnace dust contains valuable metals like iron and zinc. The high temperature and the oxidizing conditions in the off-gas stream of the electric arc furnace form iron (III)oxide (Fe2O3), zinc oxide (ZnO) and zinc ferrite (ZnOFe2O3). The state-of-the-art treatment for EAFD is based on the carbothermal reduction of these oxides and thus emitting CO2 contributing to the anthropogenic climate change. An approach to reduce CO2 emissions in electric arc furnace dust recycling processes is the substitution of carbon with hydrogen. An economic evaluation of the industrial feasibility of using hydrogen requires basic research dealing with its influence on the reduction behavior of iron (III) oxide (Fe2O3) and zinc ferrite (ZnOFe2O3), when carbon is substituted with hydrogen. This work gives an insight into thermogravimetric analysis comparing carbon monoxide and hydrogen-based reduction in a tailor-made thermogravimetric analysis instrument (TGA). It allows for the investigation of sole reactions with mixtures of hydrogen and water vapor, showing that the reduction of Fe2O3 is three times and the reduction of ZnOFe2O3 two times faster when hydrogen substitutes carbon monoxide at 800 C.