Download or read book Phase field Investigation on the Non equilibrium Interface Dynamics of Rapid Alloy Solidification written by and published by . This book was released on 2011 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt: The research program reported here is focused on critical issues that represent conspicuous gaps in current understanding of rapid solidification, limiting our ability to predict and control microstructural evolution (id est morphological dynamics and microsegregation) at high undercooling, where conditions depart significantly from local equilibrium. More specifically, through careful application of phase-field modeling, using appropriate thin-interface and anti-trapping corrections and addressing important details such as transient effects and a velocity-dependent (id est adaptive) numerics, the current analysis provides a reasonable simulation-based picture of non-equilibrium solute partitioning and the corresponding oscillatory dynamics associated with single-phase rapid solidification and show that this method is a suitable means for a self-consistent simulation of transient behavior and operating point selection under rapid growth conditions. Moving beyond the limitations of conventional theoretical/analytical treatments of non-equilibrium solute partitioning, these results serve to substantiate recent experimental findings and analytical treatments for single-phase rapid solidification. The departure from the equilibrium solid concentration at the solid-liquid interface was often observed during rapid solidification, and the energetic associated non-equilibrium solute partitioning has been treated in detail, providing possible ranges of interface concentrations for a given growth condition. Use of these treatments for analytical description of specific single-phase dendritic and cellular operating point selection, however, requires a model for solute partitioning under a given set of growth conditions. Therefore, analytical solute trapping models which describe the chemical partitioning as a function of steady state interface velocities have been developed and widely utilized in most of the theoretical investigations of rapid solidification. However, these solute trapping models are not rigorously verified due to the difficulty in experimentally measuring under rapid growth conditions. Moreover, since these solute trapping models include kinetic parameters which are difficult to directly measure from experiments, application of the solute trapping models or the associated analytic rapid solidification model is limited. These theoretical models for steady state rapid solidification which incorporate the solute trapping models do not describe the interdependency of solute diffusion, interface kinetics, and alloy thermodynamics. The phase-field approach allows calculating, spontaneously, the non-equilibrium growth effects of alloys and the associated time-dependent growth dynamics, without making the assumptions that solute partitioning is an explicit function of velocity, as is the current convention. In the research described here, by utilizing the phase-field model in the thin-interface limit, incorporating the anti-trapping current term, more quantitatively valid interface kinetics and solute diffusion across the interface are calculated. In order to sufficiently resolve the physical length scales (id est interface thickness and diffusion boundary length), grid spacings are continually adjusted in calculations. The full trajectories of transient planar growth dynamics under rapid directional solidification conditions with different pulling velocities are described. As a validation of a model, the predicted steady state conditions are consistent with the analytic approach for rapid growth. It was confirmed that rapid interface dynamics exhibits the abrupt acceleration of the planar front when the effect of the non-equilibrium solute partitioning at the interface becomes signi ficant. This is consistent with the previous linear stability analysis for the non-equilibrium interface dynamics. With an appropriate growth condition, the continuous oscillation dynamics was able to be simulated using continually adjusting grid spac...
Download or read book Phase field Investigation on the Non equilibrium Interface Dynamics of Rapid Alloy Solidication written by Jeong Yun Choi and published by . This book was released on 2011 with total page 167 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quantitative Phase Field Modelling of Solidification written by Nikolas Provatas and published by CRC Press. This book was released on 2021-10-12 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a study of phase field modelling of solidification in metal alloy systems. It is divided in two main themes. The first half discusses several classes of quantitative multi-order parameter phase field models for multi-component alloy solidification. These are derived in grand potential ensemble, thus tracking solidification in alloys through the evolution of the chemical potentials of solute species rather than the more commonly used solute concentrations. The use of matched asymptotic analysis for making phase field models quantitative is also discussed at length, and derived in detail in order to make this somewhat abstract topic accessible to students. The second half of the book studies the application of phase field modelling to rapid solidification where solute trapping and interface undercooling follow highly non-equilibrium conditions. In this limit, matched asymptotic analysis is used to map phase field evolution equations onto the continuous growth model, which is generally accepted as a sharp-interface description of solidification at rapid solidification rates. This book will be of interest to graduate students and researchers in materials science and materials engineering. Key Features Presents a clear path to develop quantitative multi-phase and multi-component phase field models for solidification and other phase transformation kinetics Derives and discusses the quantitative nature of the model formulations through matched interface asymptotic analysis Explores a framework for quantitative treatment of rapid solidification to control solute trapping and solute drag dynamics
Download or read book A Phase Field Model for Rapid Solidification with Non Equilibrium Solute Diffusion written by and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Phase Field Methods in Materials Science and Engineering written by Nikolas Provatas and published by John Wiley & Sons. This book was released on 2011-07-26 with total page 323 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive and self-contained, one-stop source discusses phase-field methodology in a fundamental way, explaining advanced numerical techniques for solving phase-field and related continuum-field models. It also presents numerical techniques used to simulate various phenomena in a detailed, step-by-step way, such that readers can carry out their own code developments. Features many examples of how the methods explained can be used in materials science and engineering applications.
Download or read book Phase Transformations in Multicomponent Melts written by Dieter M. Herlach and published by John Wiley & Sons. This book was released on 2009-06-10 with total page 435 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bringing together the concerted efforts of the multicomponent materials community in one decisive reference work, this handbook covers all the important aspects from fundamentals to applications: thermodynamics, microscopic processes, solidification, simulation and modeling. As such, it provides a vital understanding of melt and solidification processes, treating all simulation techniques for continuous and discrete systems, such as molecular dynamics, Monte Carlo, and finite elements calculations.
Download or read book A Phase field Model for Technical Alloy Solidification written by Janin Eiken and published by . This book was released on 2010 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Grand Potential Based Multi phase Field Model for Alloy Solidification written by Kaushik Shampur and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "The ability to model phase transitions in complex (i.e. multi-component and multi- phase) alloys, accurately, efficiently, and in an accessible manner, is important in material science. This thesis derives a new model that extends the quantitative model of polycrystalline solidification of Ofori-Opoku et al [3] to the case of multiple components and alloy phases through a grand potential functional description. Here, solidification is described by a set of order parameters describing solid phases and a set chemical potentials describing solute components. Solidification of a solid phase is driven by the grand potential difference between it and the liquid, expanded here to quadratic order in the chemical potential difference (relative to equilibrium) of each solute, i.e., its supersaturation. This allows us to model both near and far- from equilibrium solidification conditions, and to easily make contact with previous quantitative single-crystal phase field theories in the literature. Thermal fluctuations in the theory are treated via stochastic noise, a feature important for modelling multi-phase nucleation self-consistently. Working in the grand canonical ensemble treats the evolution of order parameter and chemical potential as a coupled process, unique compared to the traditional methods. As a result, complete decoupling of all diffusion fields and order parameter fields is achieved at equilibrium, making it possible to easily set solid-liquid or solid- solid interface energy independently of solute distribution across an an interface, an important feature for quantitative meso-scale calculations. Chemical diffusion equations in the model are augmented by a non-variational, so-called anti-trapping flux in each solute species. These fictitious fluxes are used in the literature in some phase field theories to correct for spurious solute trapping effects caused by the use of a diffuse interface, which is done solely for numerical expediency.We demonstrate its workings of our model in the limit of a two-component eutectic alloy system simulated with 2D dynamic adaptive mesh refinement. Benchmark eutectic lamellar simulations and measurements are first performed. Following that, two-phase homogenous nucleation and growth are examined. In the limit of near- equilibrium interfaces (zero interface kinetics), we illustrate two-phase grain growth scaling that is independent of nucleation barrier." --
Download or read book Nonequilibrium Solidification of Nondilute Alloys written by David Paul Brunco and published by . This book was released on 1995 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Phase field method and integrated computing materials engineering written by Yu-Hong Zhao and published by Frontiers Media SA. This book was released on 2023-04-19 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Solidification written by Michel Rappaz and published by EPFL Press. This book was released on 2009-08-21 with total page 656 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solidification is one of the oldest processes for producing useful implements and remains one of the most important modern commercial processes. This text describes the fundamentals of the technology in a coherent way, using consistent notation.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Selected Works of John W Cahn written by W. Craig Carter and published by John Wiley & Sons. This book was released on 2013-10-28 with total page 830 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book represents a collection of 30 selected papers from the work of John W. Cahn. Dr. Cahn is Senior Fellow at the Materials Science and Engineering Laboratory of the National Institute of Standards and Technology, and is widely recognized as a founder of modern theory and thought in materials science. The range of his research included kinetics and mechanisms of metallurgical phase changes, surfaces, interfaces, defects, quasicrystals, thermodynamics, and other areas impacting the fundamental understanding of materials science. Each paper includes a 2-4 page review of the impact and historical perspective of the work. This is an important collection for students, instructors, and scientists interested in materials science.
Download or read book Phase field Simulations of Rapid Solidification in Binary Alloys written by Jun Fan and published by . This book was released on 2005 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quantitative Phase field Model for Phase Transformations in Multi component Alloys written by Abhik Narayan Choudhury and published by Karlsruher Institut Fur Technologie. This book was released on 2014-05-13 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Phase-field modeling has spread to a variety of applications involving phase transformations.While the method has wide applicability, derivation of quantitative predictions requires deeper understanding of the coupling between the system and model parameters. The book highlights a novel phase-field model based on a grand-potential formalism allowing for an elegant and efficient solution to problems in phase transformations.
Download or read book Elements of Rapid Solidification written by Monde A. Otooni and published by Springer. This book was released on 1998 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: With contributions by numerous experts.
Download or read book Combined Molecular Dynamics and Phase Field Simulation of Crystal Melt Interfacial Properties and Microstructure Evolution During Rapid Solidification of TI NI Alloys written by Sepideh Kavousi and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
