4th World Congress on Integrated Computational Materials Engineering (ICME 2017): Microstructure Evolution - I
Program Organizers: Paul Mason, Thermo-Calc Software Inc.; Michele Manuel, University of Florida; Alejandro Strachan, Purdue University; Ryan Glamm, Boeing Research and Technology; Georg J. Schmitz, Micress/Aachen; Amarendra Singh, IIT Kanpur; Charles Fisher, Naval Surface Warfare Center

Monday 10:30 AM
May 22, 2017
Room: Salon IV
Location: Ann Arbor Marriott Ypsilanti at Eagle Crest

10:30 AM  
SPPARKS - A Platform for Simulation of Material Microstructures: Jonathan Madison1; Theron Rodgers1; Veena Tikare1; 1Sandia National Laboratories
     Integrated Computational Materials Engineering (ICME) hinges upon the enabling interactions of simulation with experiments to hasten, improve and bolster the design cycle for materials. This requires simulation tools which are properly scoped, reliable and sometimes flexible to the need at hand. With regard to meso-scale microstructural predictions, few simulation codes currently exist which are readily extensible, maintain low computational overhead, are applicable to a variety of material phenomena and are also free of cost. However, Sandia’s SPPARKS platform, which is an acronym for Stochastic Parallel PARticle Kinetic Simulator, is. This talk will present an overview as well as a few select user routines from within SPPARKS which provide first order approximations of microstructure undergoing coarsening, static or dynamic recrystallization, laser-welding and even additive manufacturing.Sandia National Laboratories is a multi-mission laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000

10:50 AM  
Extending CALPHAD Based Tools with Process-Structure-Property Models to Develop a Computational Materials Design Platform: Johan Jeppsson1; Adam Hope1; Kevin Wu1; Qing Chen1; Johan Bratberg1; Anders Engström1; Ralf Rettig1; 1Thermo-Calc Software
    CALPHAD is a phase based approach to describe the underlying thermodynamics and diffusion in complex, multicomponent systems taking into consideration composition and temperature variations. In the early days of CALPHAD, predictions were limited to thermodynamic equilibrium. The approach was then extended to consider diffusion controlled kinetics. More recently, development has focused on precipitation kinetics and also the modelling of microstructure evolution through phase field. This enables the predictive modelling of process-structure with variations in chemistries essential for materials design. The ultimate interest in materials design or Integrated Computational Materials Engineering (ICME) is understanding material properties or possibly performance, and to reach there we need process-structure-property relationships. New work is now focusing on the integration of process-structure-property models into Thermo-Calc to provide a framework for computational materials design. This presentation will describe the development of property models and how Thermo-Calc users can implement own property models using the script language Jython(Python for Java VM). In addition, new functionality and infrastructure supporting computer aided materials design will be discussed and It will be shown how to visualize and export the results from property models.

11:10 AM  Cancelled
Microstructural Design of Thermal Sprayed Chromium Oxide Coatings: Tatu Pinomaa1; Tom Andersson1; Anssi Laukkanen1; Tomi Suhonen1; Jarkko Metsäjoki1; Nikolas Provatas2; 1VTT Technical Research Centre of Finland; 2McGill University
    We present an approach to virtually design thermal spray coatings. Thermal spray coatings are deposited by melting and propelling micron-sized particles to a surface, resulting in a submillimeter-thick lamellar film. The coating microstructure forms via accumulation of rapidly solidified splats, which are modeled with a multi-order parameter phase-field model. A mesoscale finite-element model is then used to to relate microstructure properties–such as texture and interlamellar adhesion–to mechanical response of the coating. A set of simulated rapidly solidified chromium oxide microstructures are sampled to produce a complete synthetic coating. In addition, a set of scanning electron microscope (SEM) images are segmented and sampled to represent a coating volume. The simulation-based and SEM-based representations are compared: first their microstructural features, and second their mechanical properties. Finally, the simulation and SEM-based methods are combined to produce a richer representation of the coating. The lamellar and coating-substrate adhesion strengths tend to bottleneck the coating performance, and therefore these interface regions are treated with special care. The chromium oxide tends to reduce into metallic chromium, and the portion of chromium is varied to see its influence on the coating performance.

11:30 AM  
Multi-Scale Modeling of Quasi-Directional Solidification of a Cast Si-rich Eutectic Alloy: Chang Kai Wu1; Kwan Skinner1; Andres Becerra1; Vasgen Shamamian1; Salem Mosbah2; 1Dow Performance Silicones; 2Think Solidification, LLC
     Dow Corning Corporation recently examined the use of transition metal-silicon eutectics for producing melt-castable ceramic parts. These materials display good strength, wear and corrosion resistance. The near-eutectic solidification structure has significant impact on the final properties of a cast component. However, direct simulation of the cast structure at industrial scales remains a challenge. The objective of this work is to develop a multi-scale integrated solidification model that includes: density functional theory (DFT) calculations, which enable the computation of difficult-to-measure thermophysical properties; microstructural evolution simulation, which tackles nucleation eutectic growth and segregation during solidification; and casting modeling, which accounts for different boundary conditions including temperature-dependent heat transfer coefficients and geometry. The developed 3D coupled code can predict the correct morphology of the solidified composite and aid in the design and optimization of melt-cast parts based on composition and process parameters in a virtual environment. To verify the model, a mold was designed to achieve quasi-directional solidification within large regions of each casting; hypo- and hyper-eutectic Si-Cr alloys were cast into this custom mold using a vacuum tilt pour unit. Our experimental efforts focused on the quantification of the effects of process conditions on the resulting microstructure of the cast component. Local segregation was examined and compared with the model’s predictions. Results are in agreement with the microstructure observed in our castings.

11:50 AM  
A Model for Prismatic Grain Growth in Cemented Carbides (P-4): Manon Bonvalet1; Joakim Odqvist1; Annika Borgenstam1; John Ågren1; 1KTH - Royal Institute of Technology
    Cemented carbides, consisting of hard WC grains embedded in a ductile matrix (Co for instance), are used in the manufacturing industry, for e.g. cutting tools, thanks to an interesting combination of hardness and toughness. These mechanical properties are mainly due to the average grain size and the grain size distribution, and consequently the prediction of their evolution and the understanding of the physical phenomena driving it are of a great importance. Cemented carbides are made by liquid phase sintering and during this process abnormal grain growth may occur, i.e. few large grains of WC, consume the small neighbouring grains. This phenomenon cannot be explained in view of the classical LSW theory. The flat surface planes of the grains observed experimentally suggest that the grain coarsening is controlled by interface reaction. The 2D nucleation of new atomic layers on the different facets consumes a part of the driving force for coarsening. Our grain growth model deals with this 2D nucleation but also with the mass transfer across the interface and the long-range diffusion during growth. These phenomena are coupled in series. In addition, the prismatic grain shape and the anisotropic interfacial energy are taken into account. The driving force for coarsening, which is written for a non-spherical grain, is dissipated by different physical phenomena and the interfacial energy of different grain facets. A Kampmann-Wagner approach is used to describe the evolution of the grain size distribution within the system over time. Predictions are compared with experimental results for different multicomponent systems.

12:10 PM Break