Phase Transformations


Book Description

The terms phase transitions and phase transformations are often used in an interchangeable manner in the metallurgical literature. In Phase Transformations, transformations driven by pressure changes, radiation and deformation and those occurring in nanoscale multilayers are brought to the fore. Order-disorder transformations, many of which constitute very good examples of continuous transformations, are dealt with in a comprehensive manner. Almost all types of phase transformations and reactions that are commonly encountered in inorganic materials are covered and the underlying thermodynamic, kinetic and crystallographic aspects elucidated. - Shows readers the advancements in the field - due to enhanced computing power and superior experimental capability - Drawing upon the background and the research experience of the authors, bringing together a wealth of experience - Written essentially from a physical metallurgists view point




NBS Special Publication


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The Role of Convection and Fluid Flow in Solidification and Crystal Growth


Book Description

Physicochemical Hydrodynamics: The Role of Convection and Fluid Flow in Solidification and Crystal Growth focuses on the processes, methodologies, reactions, and approaches involved in solidification and crystal growth brought about by convection and fluid flow. The selection first offers information on the techniques of crystal growth, convection in Czochralski growth melts, and Marangoni effects in crystal growth melts. Discussions focus on crystal growth under reduced gravity, Marangoni effects in growth from a crucible, thermocapillary convection in floating zones, near-field flow, Czochralski bulk flow, and melt, solution, and vapor growth. The text then examines the effect of convective flow on morphological stability and time-dependent natural convection in crystal growth systems. The manuscript elaborates on the effects of fluid flow on the solidification of industrial castings and ingots and application of holographic interferometry to hydrodynamic phenomena in crystal growth. Topics include effects of fluid flow on crystal structure, importance of macrosegregation defects in castings, value of convection in crystal growth, and occurrence of thermal oscillations in fluids. The selection is a dependable reference for readers interested in the role of convection and fluid flow in solidification and crystal growth.




Theory of Solidification


Book Description

The processes of freezing and melting were present at the beginnings of the Earth and continue to dominate the natural and industrial worlds. The solidification of a liquid or the melting of a solid involves a complex interplay of many physical effects. This 2001 book presents in a systematic way the field of continuum solidification theory based on instability phenomena. An understanding of the physics is developed by using examples of increasing complexity with the object of creating a deep physical insight applicable to more complex problems. Applied mathematicians, engineers, physicists, and materials scientists will all find this volume of interest.







Morphology of Crystals


Book Description

The molecular mechanisms underlying the fact that a crystal can take a variety of external forms is something we have come to understand only in the last few decades. This is due to recent developments in theoretical and experimental investigations of crystal growth mechanisms. Morphology of Crystals is divided into three separately available volumes. Part A contains chapters on roughening transition; equilibrium form; step pattern theory; modern PBC; and surface microtopography. This part provides essentially theoretical treatments of the problem, particularly the solid-liquid interface. Part B contains chapters on ultra-fine particles; minerals; transition from polyhedral to dendrite; theory of dendrite; and snow crystals. All chapters are written by world leaders in their respective areas, and some can be seen as representing the essence of a life's work. This is the first English-language work which covers all aspects of the morphology of crystals - a topic which has attracted top scientific minds for centuries. As such, it is indispensable for anyone seeking an answer to a question relating to this fascinating problem: mineralogists, petrologists, crystallographers, materials scientists, workers in solid-state physics and chemistry, etc. In Parts A: Fundamentals and B: Fine Particles, Minerals and Snow equilibrium and kinetic properties of crystals are generally approached from an `atomistic' point of view. In contrast, Part C: The Geometry of Crystal Growth follows the alternative and complementary `geometrical' description, where bulk phases are considered as continuous media and their interfaces as mathematical surfaces with orientation-dependent properties. Equations of motion for a crystal surface are expressed in terms of vector and tensor operators working on surface free energy and growth rate, both expressed as functions of surface orientation and driving force, or `affinity' for growth. This approach emphasizes the interrelation between equilibrium and kinetic behavior. Part 1 establishes the theoretical framework. Part 2 gives a construction toolbox for explicit (analytic) functions. An extra chapter is devoted to experimental techniques for measuring such functions: a new approach to sphere growth experiments. The emphasis throughout is on principles and new concepts. Audience: Advanced readers familiar with traditional aspects of crystal growth theory. Can be used as the basis for an advanced course, provided supplementation is provided in the areas of atomistic models of the advancing surface, diffusion fields, etc.




Report of NRL Progress


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Publications


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Variational and Free Boundary Problems


Book Description

This IMA Volume in Mathematics and its Applications VARIATIONAL AND FREE BOUNDARY PROBLEMS is based on the proceedings of a workshop which was an integral part of the 1990- 91 IMA program on "Phase Transitions and Free Boundaries. " The aim of the workshop was to highlight new methods, directions and problems in variational and free boundary theory, with a concentration on novel applications of variational methods to applied problems. We thank R. Fosdick, M. E. Gurtin, W. -M. Ni and L. A. Peletier for organizing the year-long program and, especially, J. Sprock for co-organizing the meeting and co-editing these proceedings. We also take this opportunity to thank the National Science Foundation whose financial support made the workshop possible. Avner Friedman Willard Miller, Jr. PREFACE In a free boundary one seeks to find a solution u to a partial differential equation in a domain, a part r of its boundary of which is unknown. Thus both u and r must be determined. In addition to the standard boundary conditions on the un known domain, an additional condition must be prescribed on the free boundary. A classical example is the Stefan problem of melting of ice; here the temperature sat isfies the heat equation in the water region, and yet this region itself (or rather the ice-water interface) is unknown and must be determined together with the tempera ture within the water. Some free boundary problems lend themselves to variational formulation.