Download or read book Microgravity and Dendritic Solidification at Low Speed written by D. Camel and published by . This book was released on 1987 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Solidification and Microgravity written by P. Barczy and published by Trans Tech Publications Ltd. This book was released on 1991-01-01 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: The volume presents invited papers on topics of current interest.

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 Alloy Solidification and Quantification of Equiaxed Dendritic Growth and Motion in Microgravity and Terrestrial Conditions written by Sathya Velayutham and published by . This book was released on 2018 with total page 116 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 Spurious Grain Formation During Directional Solidification in Microgravity written by Supriya Ramashankar Upadhyay and published by . This book was released on 2018 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research is aimed at carrying out a systematic investigation of the nucleation, and growth of spurious "misoriented" grains during directional solidification in the low gravity environment of space. Three Al–7 wt. % Si alloy cylindrical samples (MICAST-6, MICAST-7 and MICAST2-12) were directionally solidified on the Space Station at growth speeds varying from 5 to 50 μms-1 under thermal gradients varying from 14 to 33 K cm-1 in alumina crucibles, under a joint NASA-ESA (European Space Agency) project called, MICAST (Microstructure formation in casting of technical alloys under a diffusive and magnetically controlled convection conditions). The primary purpose of directionally solidifying these three Al-7Si samples in the low gravity environment of space was to eliminate gravity-induced convection in the melt, and grow dendrite array morphology under purely diffusive transport conditions. However, when these directionally solidified samples were extracted from their alumina crucibles, they all showed evidence of surface pores along their length. We believe that these pores formed because in microgravity, there is no imposed force to pull the liquid column down on to the solidifying portion below to continue to feed the volume shrinkage due to liquid to solid phase transformation. There was no additional built-in mechanism, such as a piston and spring, in the MICAST ampoules to keep the melt column pressed onto the solid below. We also believe that even in the absence of gravity, a liquid coulmn which gets detached from the crucible internal waals (forming surface pores), under an imposed positive thermal gradient, would lead to the liquid-solid surface energy driven Marangoni convection. This convection may fragment fragile secondary or tertiary arms of the primary dendrite trees growing in the mushy zone. These broken dendrite solid fragments may lead to the nucleation and growth of spurious grains in the MICAST samples, where the orientation of primary dendrites would be very different from those in their unmelted seed portions. Our purpose is to examine the longitudinal and transverse microstructures of these MICAST samples to study the formation of spurious grains, and investigate if there is any correlation between the location of the observed surface pores and the formation of spurious grains.

Download or read book Dynamical Theory of Dendritic Growth in Convective Flow written by Jian-Jun Xu and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 243 pages. Available in PDF, EPUB and Kindle. Book excerpt: Convective flow in the liquid phase is always present in a realistic process of freezing and melting and may significantly affect the dynamics and results of the process. The study of the interplay of growth and convection flow during the solidification has been an important subject in the broad fields of materials science, condensed matter physics, fluid physics, micro-gravity science, etc. The present book is concerned with the dynamics of free dendritic growth with convective flow in the melt. It systematically presents the results obtained in terms of a unified asymptotic approach in the framework of the interfacial wave (IFW) theory. In particular, the book explores the effect of the various types of convection flow on the selection and pattern formation of dendritic growth based on the global stability analysis.

Download or read book Advanced Materials 93 written by T Matsumoto and published by Newnes. This book was released on 2012-12-02 with total page 809 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Interactive Dynamics of Convection and Solidification written by Peter Ehrhard and published by Springer Science & Business Media. This book was released on 2013-03-14 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: Crystal growth, casting, soldering, welding, high-energy surface treatment, nuclear safety systems and geophysical flows are just a few examples where solidification and convection occur together. These processes are interactive on micro- and macroscales: flow affects the distribution of heat and species and hence the freezing process, while solidification evolves flow boundaries, as in crusting, for example, and hence can radically alter the convection. Mathematical modellers, experimentalists and applied scientists were invited to this colloquium with the aim of consolidating our understanding of such interactions, of identifying key outstanding issues, and of developing new approaches in this important area of fundamental research. Both invited and contributed papers focus on both fundamental and technologically relevant problems.

Download or read book Experimental Methods for Microgravity Materials Science Research written by Robert A. Schiffman and published by Minerals, Metals, & Materials Society. This book was released on 1988 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceeding of the Second International Symposium on [title] held Feb., 1988, Phoenix, Ariz. The 25 papers included in this volume detail research techniques being used in earth-based simulations, and also planned experimentation techniques to be used upon resumption of the space shuttle program. No

Download or read book Microgravity Science and Applications Program Tasks written by United States. Office of Space Science and Applications and published by . This book was released on 1988 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book NASA Technical Memorandum written by and published by . This book was released on 1994 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Study on the Growth Anomaly in Al Ni Melts Under Gravity and Microgravity Conditions written by Marcus Reinartz and published by . This book was released on 2020* with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis the solidification behaviour of different Al-Ni alloys is studied by means of the electromagnetic levitation (EML) technique. Of special interest is an anomaly of the growth behaviour, a decreasing solidification velocity for increasing undercooling. However, according to theoretical considerations the growth velocity should increase with increasing undercooling. In order to study the anomaly, levitation experiments on earth (1g) as well as levitation experiments using the electromagnetic levitation facility on board the International Space Station (ISS) are carried out. The electromagnetic levitator on board the ISS (ISS-EML) provides a unique processing environment in microgravity μg where external influences are severely reduced. The new results obtained in μg and 1g show no difference in terms of the growth velocity. However, the high-speed video data used to capture the solidification show an unexpected behaviour. The visible front consists of circular features which grow and consecutively form, referred to as scales. The measured front velocity is therefore a superposition of formation of new and growth of the existing scales. Accompanying microstructure analyses of samples processed on earth show that each scale corresponds to a nucleation event. It is concluded that the observed front is not a dendritic growth front, but a nucleation front. This resolves the contradiction between experimental results and theoretical considerations since the theoretical approaches are valid only for dendritic growth fronts. For a better understanding of its behaviour, the nucleation front is studied in greater detail. The number and size of the scales is measured. It is found that for an increasing undercooling fewer, yet larger scales form. The loss of nuclei is not compensated by the larger area, and therefore leads to a decrease of the front velocity. The velocity of the dendrites cannot be measured due to the opacity of the melt.

Download or read book NASA s Microgravity Technology Report Summary of Activities 1997 written by and published by . This book was released on 1998 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book 50 Years Progress in Crystal Growth written by Robert Feigelson and published by Elsevier. This book was released on 2004-07-09 with total page 269 pages. Available in PDF, EPUB and Kindle. Book excerpt: There is no question that the field of solid state electronics, which essentially began with work at Bell laboratories just after World War II, has had a profound impact on today's Society. What is not nearly so widely known is that advances in the art and science of crystal growth underpin this technology. Single crystals, once valued only for their beauty, are now found, in one form or another in most electronic, optoelectronic and numerous optical devices. These devices, in turn, have permeated almost every home and village throughout the world. In fact it is hard to imagine what our electronics industry, much less our entire civilization, would have been like if crystal growth scientists and engineers were unable to produce the large, defect free crystals required by device designers. This book brings together two sets of related articles describing advances made in crystal growth science and technology since World War II. One set is from the proceedings of a Symposium held in August 2002 to celebrate 50 years of progress in the field of crystal growth. The second contains articles previously published in the newsletter of the American Association for Crystal Growth in a series called "Milestones in Crystal Growth".The first section of this book contains several articles which describe some of the early history of crystal growth prior to the electronics revolution, and upon which modern crystal growth science and technology is based. This is followed by a special article by Prof. Sunagawa which provides some insight into how the successful Japanese crystal growth industry developed. The next section deals with crystal growth fundamentals including concepts of solute distribution, interface kinetics, constitutional supercooling, morphological stability and the growth of dendrites. The following section describes the growth of crystals from melts and solutions, while the final part involves thin film growth by MBE and OMVPE.These articles were written by some of the most famous theorists and crystal growers working in the field. They will provide future research workers with valuable insight into how these pioneering discoveries were made, and show how their own research and future devices will be based upon these developments. · Articles written by some of the most famous theorists and crystal growers working in the field· Valuable insight into how pioneering discoveries were made.· Show how their own research and future devices will be based upon these developments

Download or read book Materials Processing in the Reduced Gravity Environment of Space Volume 87 written by Robert H. Doremus and published by Mrs Proceedings. This book was released on 1987 with total page 394 pages. Available in PDF, EPUB and Kindle. Book excerpt: The MRS Symposium Proceeding series is an internationally recognised reference suitable for researchers and practitioners.

Download or read book Ultrahigh and High speed Photography Videography and Photonics written by and published by . This book was released on 1993 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: