Nucleation and the Properties of Undercooled Melts

Nucleation and the Properties of Undercooled Melts PDF Author: Livio Battezzati
Publisher: Trans Tech Publications Ltd
ISBN: 3035705968
Category : Technology & Engineering
Languages : en
Pages : 80

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Book Description
Nucleation is a central topic in Materials Science because it initiates most phase transformations. When a new phase appears within an existing phase, seeds must form before growth can occur within the given volume. The study of nucleation treats the very early stages, which involve only a limited number of atoms or molecules. It is a branch of fundamental research which has far-reaching implications for processes where nucleation is of paramount relevance to phase and microstructure selection. The development of any new material or processing route always leads to renewed interest in the topic.

Nucleation and the Properties of Undercooled Melts

Nucleation and the Properties of Undercooled Melts PDF Author: Livio Battezzati
Publisher: Trans Tech Publications Ltd
ISBN: 3035705968
Category : Technology & Engineering
Languages : en
Pages : 80

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Book Description
Nucleation is a central topic in Materials Science because it initiates most phase transformations. When a new phase appears within an existing phase, seeds must form before growth can occur within the given volume. The study of nucleation treats the very early stages, which involve only a limited number of atoms or molecules. It is a branch of fundamental research which has far-reaching implications for processes where nucleation is of paramount relevance to phase and microstructure selection. The development of any new material or processing route always leads to renewed interest in the topic.

Nucleation and the Properties of Undercooled Melts

Nucleation and the Properties of Undercooled Melts PDF Author: L. Battezzati
Publisher: Trans Tech Publications
ISBN:
Category : Science
Languages : en
Pages : 86

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Book Description
The study of nucleation refers to the early stages of materials phase transformations in which a limited number of atoms or molecules are involved in the formation of seeds as a new phase originates from a matrix. Battezzati and Castellero (both: chemistry, U. of Torino, Italy) describe the theory of nucleation and discuss the thermophysical properties which mostly influence its rate. Although the material mostly focuses on classical theory starting from heterophase fluctuations, other theories are also described. Also included is a detailed analysis of quantities related to solidification. Annotation copyrighted by Book News Inc., Portland, OR.

Solidification of Containerless Undercooled Melts

Solidification of Containerless Undercooled Melts PDF Author: Dieter M. Herlach
Publisher: John Wiley & Sons
ISBN: 3527647929
Category : Technology & Engineering
Languages : en
Pages : 569

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Book Description
All metallic materials are prepared from the liquid state as their parent phase. Solidification is therefore one of the most important phase transformation in daily human life. Solidification is the transition from liquid to solid state of matter. The conditions under which material is transformed determines the physical and chemical properties of the as-solidified body. The processes involved, like nucleation and crystal growth, are governed by heat and mass transport. Convection and undercooling provide additional processing parameters to tune the solidification process and to control solid material performance from the very beginning of the production chain. To develop a predictive capability for efficient materials production the processes involved in solidification have to be understood in detail. This book provides a comprehensive overview of the solidification of metallic melts processed and undercooled in a containerless manner by drop tube, electromagnetic and electrostatic levitation, and experiments in reduced gravity. The experiments are accompanied by model calculations on the influence of thermodynamic and hydrodynamic conditions that control selection of nucleation mechanisms and modify crystal growth development throughout the solidification process.

Science and Technology of the Undercooled Melt

Science and Technology of the Undercooled Melt PDF Author: P.R. Sahm
Publisher: Springer Science & Business Media
ISBN: 940094456X
Category : Science
Languages : en
Pages : 296

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Book Description
"SCIENCE AND TECHNOLOGY OF '!HE UNDEROLED MELT" This title was chosen as the topical headline of the Advanced Research Workshop (ARW) from March 17 to 22 1985, held at the Castle of Theuern. The usual term "Rapid Solidification" is an overlapping description. Due to the fact that nucleation is so eminently important for the undercooling of a melt and this, in turn, is an important characteristic of rapid solidifi cation, undercooling plays an essential role in "rapid solidification." The undercooled melt has caused an "accelerated evolution" (if not a revolution) in materials science during the last decade. Several rather exciting concepts with interesting potential for novel applications are being pursued presently in various laboratories and companies. They concern not only new processes and ha~ware developments, but also present chal lenging perspectives for ventures, including the founding of new companies; or they promise growth possibilities with established larger and smaller industrial establishments.

Containerless Processing of Undercooled Melts

Containerless Processing of Undercooled Melts PDF Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781722128074
Category :
Languages : en
Pages : 28

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Book Description
The investigation focused on the control of microstructural evolution in Mn-Al, Fe-Ni, Ni-V, and Au-Pb-Sb alloys through the high undercooling levels provided by containerless processing, and provided fundamental new information on the control of nucleation. Solidification analysis was conducted by means of thermal analysis, x-ray diffraction, and metallographic characterization on samples processed in a laboratory scale drop tube system. The Mn-Al alloy system offers a useful model system with the capability of phase separation on an individual particle basis, thus permitting a more complete understanding of the operative kinetics and the key containerless processing variables. This system provided the opportunity of analyzing the nucleation rate as a function of processing conditions and allowed for the quantitative assessment of the relevant processing parameters. These factors are essential in the development of a containerless processing model which has a predictive capability. Similarly, Ni-V is a model system that was used to study duplex partitionless solidification, which is a structure possible only in high under cooling solidification processes. Nucleation kinetics for the competing bcc and fcc phases were studied to determine how this structure can develop and the conditions under which it may occur. The Fe-Ni alloy system was studied to identify microstructural transitions with controlled variations in sample size and composition during containerless solidification. This work was forwarded to develop a microstructure map which delineates regimes of structural evolution and provides a unified analysis of experimental observations. The Au-Pb-Sb system was investigated to characterize the thermodynamic properties of the undercooled liquid phase and to characterize the glass transition under a variety of processing conditions. By analyzing key containerless processing parameters in a ground based drop tube study, a carefully designed flight experiment may b...

Metastable Solids from Undercooled Melts

Metastable Solids from Undercooled Melts PDF Author: Dieter Herlach
Publisher: Elsevier
ISBN: 0080468861
Category : Technology & Engineering
Languages : en
Pages : 445

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Book Description
This book presents the physical concepts and tools to characterize and describe the formation of metastable solids from undercooled melts. Its aim is to facilitate understanding of the development of the science and technology of solidification of melts and to introduce new concepts within this exciting research field in order to fulfil the challenges of the future in the field of undercooled melts. A comprehensive description of the science and applications of the undercooling phenomenon is given. It is composed of several main parts: experimental techniques for undercooling; characterization of the undercooled melt as the first step in rapid solidification; introducing the concepts of modern theories of rapid dendrite and eutectic growth and their comparison with experimental results, and a survey of metastable materials formed from the non-equilibrium state of an undercooled melt. * Showing clear links to possible application of results obtained from basic research * The subject matter is multidisciplinary and will be of interest to material scientists, physicists, physical chemists, mechanical and electrical engineers

Nucleation in Condensed Matter

Nucleation in Condensed Matter PDF Author: Ken Kelton
Publisher: Elsevier
ISBN: 0080912648
Category : Technology & Engineering
Languages : en
Pages : 759

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Book Description
In Nucleation in Condensed Matter, key theoretical models for nucleation are developed and experimental data are used to discuss their range of validity. A central aim of this book is to enable the reader, when faced with a phenomenon in which nucleation appears to play a role, to determine whether nucleation is indeed important and to develop a quantitative and predictive description of the nucleation behavior. The third section of the book examines nucleation processes in practical situations, ranging from solid state precipitation to nucleation in biological systems to nucleation in food and drink. Nucleation in Condensed Matter is a key reference for an advanced materials course in phase transformations. It is also an essential reference for researchers in the field. Unified treatment of key theories, experimental evaluations and case studies Complete derivation of key models Detailed discussion of experimental measurements Examples of nucleation in diverse systems

Advanced Materials '93

Advanced Materials '93 PDF Author: T Matsumoto
Publisher: Newnes
ISBN: 0444601155
Category : Technology & Engineering
Languages : en
Pages : 809

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Book Description
Computations, Glassy Materials, Microgravity and Non-Destructive Testing is a compilation of the papers presented during the Third IUMRS International Conference on Advanced Materials International Union of The Materials Research Societies that discussed the concepts and methods behind glassy materials. The book is divided into parts. Part 1 tackles the progresses in sol-gel science and technology; the reaction mechanisms of ormosils and effects of ultrasonic irradiation; and the preparation of different glasses and their properties. Part 2 covers topics such as the neural network system for the identification of materials; the use of computers for simulations of many-body systems; computer system for meeting the supercomputing needs of materials; quality control of materials information by knowledge base; and the development of knowledgebase system for computer-assisted alloy design. Part 3 deals with the properties of different materials, the concepts, and the techniques behind them, and Part 4 discusses the non-destructive evaluation. The text is recommended for chemists and engineers in the field of materials science, especially those who wish to know more about the progress in its field of research.

NASA Technical Memorandum

NASA Technical Memorandum PDF Author: United States. National Aeronautics and Space Administration
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 464

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Book Description


Microgravity Science & Applications

Microgravity Science & Applications PDF Author:
Publisher:
ISBN:
Category : Gravity
Languages : en
Pages : 390

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Book Description