High-speed Imaging and Analysis of the Solidification of Undercooled Alloy Melts
Author: John William Lum
Publisher:
Published: 1996
Total Pages: 200
ISBN-13:
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Solidification of Containerless Undercooled Melts
Author: Dieter M. Herlach
Publisher: John Wiley & Sons
Published: 2012-05-21
Total Pages: 569
ISBN-13: 3527647929
DOWNLOAD EBOOKAll 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
Author: P.R. Sahm
Publisher: Springer Science & Business Media
Published: 2012-12-06
Total Pages: 296
ISBN-13: 940094456X
DOWNLOAD EBOOK"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.
Rapid Solidification of Undercooled Melts
Author: Xiaolong Xu
Publisher:
Published: 2018
Total Pages:
ISBN-13:
DOWNLOAD EBOOKRapid 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.
Metastable Microstructures
Author: Dipankar Banerjee
Publisher:
Published: 1993
Total Pages: 360
ISBN-13:
DOWNLOAD EBOOKProceedings of the Merton C. Flemings Symposium on Solidification and Materials Processing
Author: Merton C. Flemings
Publisher: Minerals, Metals, & Materials Society
Published: 2001
Total Pages: 568
ISBN-13:
DOWNLOAD EBOOKThis 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.
TMS 2013 142nd Annual Meeting and Exhibition
Author: The Minerals, Metals & Materials Society (TMS)
Publisher: John Wiley & Sons
Published: 2013-02-22
Total Pages: 1238
ISBN-13: 1118663136
DOWNLOAD EBOOKPresenting 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.
Solidification at the High and Low Rate Extreme
Author: Halim Meco
Publisher:
Published: 2004
Total Pages: 398
ISBN-13:
DOWNLOAD EBOOKThe 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.
Rapidly Quenched Metals
Author: S Steeb
Publisher: Elsevier
Published: 2012-12-02
Total Pages: 1163
ISBN-13: 0444601112
DOWNLOAD EBOOKRapidly 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.
A Review: Chill-Block Melt Spin Technique, Theories & Applications
Author: Mustafa Kamal
Publisher: Bentham Science Publishers
Published: 2013-03-15
Total Pages: 192
ISBN-13: 160805151X
DOWNLOAD EBOOKRapid 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.
