Download or read book High speed Imaging and Analysis of the Solidification of Undercooled Alloy Melts written by John William Lum and published by . This book was released on 1996 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Solidification of Containerless Undercooled Melts written by Dieter M. Herlach and published by John Wiley & Sons. This book was released on 2012-05-21 with total page 569 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Science and Technology of the Undercooled Melt written by P.R. Sahm and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: "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.
Download or read book Rapid Solidification of Undercooled Melts written by Xiaolong Xu and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Rapid solidification and microstructure evolution of deeply undercooled bulk concentrated Ni-20%at.Cu and Co-20%at.Pd alloys are strictly and systematically evaluated. First, thermodynamics of the undercooled melt is discussed. Consideration is provided for not only the systematic microstructure evolution within a broad undercooling range, but also the dendrite growth mechanism and the rapid solidification characteristics. The dendrite growth in the bulk undercooled melts was captured by a high speed camera. The first kind of grain refinement occurring in the low undercooling regimes was explained by a current grain refinement model. Besides for the dendrite melting mechanism, the stress originating from the solidification contraction and thermal strain in the first mushy zone during rapid solidification could be a main mechanism causing the second kind of grain refinement above the critical undercooling. This internal-stress led to the distortion and breakup of the primary dendrites and was semi-quantitatively described by a corrected stress accumulation model. It was found that the stress induced recrystallization could make the primary microstructures refine substantially after recalescence.
Download or read book Proceedings of the Merton C Flemings Symposium on Solidification and Materials Processing written by Merton C. Flemings and published by Minerals, Metals, & Materials Society. This book was released on 2001 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text comprises a collection of papers from the Merton C. Flemings Symposium held on the MIT campus in June, 2000. The papers cover such topics as dendritic solidification dynamics, control of casting quality, interdendritic fluid flow, semi-solid processing, and engineering education.
Download or read book Solidification at the High and Low Rate Extreme written by Halim Meco and published by . This book was released on 2004 with total page 398 pages. Available in PDF, EPUB and Kindle. Book excerpt: The microstructure selection at both high and low growth rates is studied. For the high rate extreme, melt spinning of a Fe-Si-B alloy is employed. The microstructural variations with changing wheel speed and factors affecting these variations are examined through various characterization techniques. Particular attention was given for the influence of melt pool behavior on the competition between nucleation of crystalline solidification products and glass formation. It is found that there exists a window of wheel speeds which give rise to a stable melt-pool and production of amorphous ribbons. The surface-controlled melt-pool oscillation is found as the dominant factor governing the onset of unsteady thermal conditions accompanied by varying amounts of crystalline nucleation observed near the lower wheel speed limit. For the upper wheel speed limit, a criterion based on mass-balance and momentum transfer is developed for predicting the window of wheel speeds for obtaining uniform and fully amorphous ribbons. For the low rate extreme, solidification and morphological selection of the faceted silicon phase is investigated in a near eutectic Al-Si system by utilizing a Bridgman type directional solidification unit. Particularly, the role of certain defect mechanisms, namely twinning, in the selection of microstructure and growth crystallography is investigated. At the imposed growth rates of 0.5 and 1 micron/s and temperature gradient of 7.5 K/mm, a unique silicon morphology consisting of 8-pointed stars is observed to grow with 001 texture within continuous domains across the sample. The growth crystallography of this unique silicon structure is characterized and it is found that substantial amount of [210] type twinning exists within the central core of this star-shaped morphology. It is found that the twinning phenomenon at the core is an essential feature for branching, morphological selection, and adjustment of spacing between the star-like silicon features. These mechanisms and the associated growth characteristics are examined in detail.
Download or read book TMS 2013 142nd Annual Meeting and Exhibition written by The Minerals, Metals & Materials Society (TMS) and published by John Wiley & Sons. This book was released on 2013-02-22 with total page 1238 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presenting papers from the 2013 annual meeting of The Minerals, Metals & Materials Society (TMS), this volume covers developments in all aspects of high temperature electrochemistry, from the fundamental to the empirical and from the theoretical to the applied.
Download or read book Metastable Microstructures written by Dipankar Banerjee and published by . This book was released on 1993 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Rapidly Quenched Metals written by S Steeb and published by Elsevier. This book was released on 2012-12-02 with total page 1163 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rapidly Quenched Metals, Volume I covers the proceedings of the Fifth International Conference on Rapidly Quenched Metals, held in Wurzburg, Germany on September 3-7, 1984. The book focuses on amorphous and crystalline metals formed by rapid quenching from the melt. The selection first covers the scope and trends of developments in rapid solidification technology, rapid solidification, and undercooling of liquid metals by rapid quenching. Discussions focus on experimental method, powders, strip, particulate production, consolidation, and alloys and alloy systems. The text then examines the solidification of undercooled liquid alloys entrapped in solid; crystallization kinetics in undercooled droplets; and grain refinement in bulk undercooled alloys. The manuscript tackles the undercooling of niobium-germanium alloys in a 100 meter drop tube; influence of process parameters on the cooling rate of the meltspinning process; and the mechanism of ribbon formation in melt-spun copper and copper-zirconium. The formation and structure of thick sections of rapidly-solidified material by incremental deposition and production of ultrafine dispersions of rare earth oxides in Ti alloys using rapid solidification are also mentioned. The selection is a valuable reference for physicists, chemists, physical metallurgists, and engineers.
Download or read book A Review Chill Block Melt Spin Technique Theories Applications written by Mustafa Kamal and published by Bentham Science Publishers. This book was released on 2013-03-15 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rapid Solidification Processing of molten metals and alloys has proved to be a reliable route for producing new and advanced materials. The Chill-Block Melt Spin (CBMS) technique is important because its simplicity, flexibility and perfection. High quality materials can be produced with lower costs, as compared to other routes, by refining the microstructure and trapping the nucleated (new) metastable phases. Melt-spun ribbons subsequently produced can then be consolidated to produce billets and sheets that can be used in many industries especially high-tech industries such as aerospace and racing automobiles. This book contains several perspectives about CBMS technology and should be a useful review for undergraduate and post-graduate metallurgy students.
Download or read book Metastable Solids from Undercooled Melts written by Dieter Herlach and published by Elsevier. This book was released on 2006-12-18 with total page 445 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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
Download or read book Masters Theses in the Pure and Applied Sciences Accepted by Colleges and Universities of the United States and Canada written by and published by . This book was released on 1996 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Containerless Processing of Undercooled Melts written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-30 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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...
Download or read book Solidification Characteristics of Aluminum Alloys written by Lars Arnberg and published by . This book was released on 1996 with total page 259 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Interface and Transport Dynamics written by Heike Emmerich and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: An overview of the recent progress of research in computational physics and materials science. Particular topics are modelling of traffic flow and complex multi-scale solidification phenomena. The sections introduce novel research results of experts from a considerable diversity of disciplines such as physics, mathematical and computational modelling, nonlinear dynamics, materials sciences, statistical mechanics and foundry technique. The book intends to create a comprehensive and coherent image of the current research status and illustrates new simulation results of transport and interface dynamics by high resolution graphics. Various possible perspectives are formulated for future activities. Special emphasis is laid on exchanging experiences concerning numerical tools and on the bridging of the scales as is necessary in a variety of scientific and engineering applications. An interesting possibility along this line was the coupling of different computational approaches leading to hybrid simulations.
Download or read book Technical Abstract Bulletin written by and published by . This book was released on 1965 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Union Membership and Employment Dynamics written by Marcus Dittrich and published by . This book was released on 2010 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
