SOLIDIFICATION

ALICIA E. ARES

INTECH

Lugar: Rijeka, Croacia; Año: 2018 p. 151

978-953-51-3905-8

In a solidification process, the material is first heated to melt and then is poured into a cavity of the mold. When the molten metal is in the mold, it begins to cool. When the temperature drops below the freezing point (melting point) of the material, solidification starts.Solidification involves a change of phase of the material and differs depending on whether the material is a pure element or an alloy. A pure metal solidifies at a constant temperature, which is its melting point (freezing point). For alloys, the solidification occurs over a temperature range depending upon the composition. Similar to the processing of metals and alloys, the thermoplastic processing depend critically on the ability to melt and process them via different processes. Many polymers do not crystallize however solidify when cooled.Inorganic glasses do not crystallize simply. The melt is every so often excessively viscous and the diffusion is too slow for crystallization advance during solidification.The Solidification book logically develops through careful presentation of relevant theories and models of solidification occurring in a variety of materials. Mathematicians, chemists, physicists, and engineers concerned with melting/freezing phenomena will also find much of value in this book.Section I: Effect of microalloying elements on the heat treatment response and tensile properties of Al-Si-Mg alloysChapter 1 (M.F. Ibrahim, M.H. Abdelaziz, H.W. Doty, S. Valtierra and F.H. Samuel) investigate the effects of alloying elements and heat treatment conditions on the microstructure and mechanical behavior of non-modified and Sr-modified 356- and 357-type alloys by examining several factors.Section II: Rapid solidification of undercooled meltsChapter 2 (Xiaolong Xu, Hua Hou and Feng Liu) The authors experimentally investigated the microstructural evolution of the Ni-20at.%Cu alloys as a function of initial undercooling and the physical mechanisms of the grain refinements occurring at low undercooling regimes. In combination with the current dendrite growth model, they theoretically analyzed the dendrite remelting in the undercooled alloys by an extended chemical superheating model for non-equilibrium solidification of undercooled binary single-phase alloys.Section III: Coupled Model of Precipitates and Microsegregation During Solidification Chapter 3 (Yandong Li, Huamei Duan and Cheng Peng) In order to understanding precipitates behavior during solidification process of micro-alloyed steel containing rare earth elements, thermodynamic calculation and equilibrium experiments were adopted to simulation the solidification process. The experiments and analysis include FactSage calculations, equilibrium experiments, thermodynamic model establishment, precipitates prediction and dynamic experiments.Section IV: Physics of solidification and microstructure. A study of AlMg and AlMgSi by Vortex methodChapter 4 (S. Valdez Rodríguez, L. Martínez-Gómez and M.I-Pech Canul) The microstructure characteristic is essential for the properties of metallic materials, included binary, ternary or eutectic alloys. Consequently even with significant progress on microstructural evolution, numerous challenges still exist for reveling the internal structure to act synergistically with matrix alloy chemical components.The authors analyses the necessary understanding of the correlation between equilibrium and non-equilibrium effects, surface energy, and chemical potential for the time of the structures formation is probably the key to solidification that can help to predict the complex of microstructures. For the case of multi-phase solidification AlMgSi alloy involves thousands of atoms, at the atomic scale, that transit to microstructures while the solid-liquid phase transformation occurs. The analysis outline the role physic solidification and the atomic arrangement influencing mechanical hardness properties and degradation resistance.Section V: Solidification versus adsorption for immobilization of pollutants in geopolymeric materialsChapter 5 (B. I. El-Eswed) The author review the latest development in the fields of immobilization of heavy metals, radio-actinides, dyes and other hazardous wastes in geopolymeric materials. Two techniques are investigated and compared; the first is solidification and the second is adsorption. Geopolymer (GP), as host for solidification and as adsorbent for adsorption, is a class of amorphous three-dimensional aluminosilicate binder material, produced by the reaction of an aluminosilicate source (metakaolin or fly ash) with a highly concentrated aqueous alkali metal silicate or hydroxide. The chapter review and evaluate solidification and adsorption of different kinds of pollutants in GP matrix. The two techniques are compared regarding efficiency or capacity of GP, reversibility of process, mechanism of adsorption or solidification, leaching of contaminants, stability of the material, cost, energy, and environmental impact. Section VI: The Application of Carbon Fiber Composites in Cryogenic Fuel TanksChapter 6 (H. Zheng, X. Zeng, J. Zhang and H. Sun) The applications of carbon fiber composites in liquid hydrogen (LH2) and liquid oxygen (LOX) fuel tanks are introduced in this chapter. The materials, processing and design of DC-XA LH2 tank, X-33 LH2 tank, SLI LH2 tank and CCTD Program tank are discussed. Lockheed Martin LOX tank and Space X Lox tank are were introduced by the authors. Technology development, materials development and development trend of cryogenic fuel tanks are discussed. Thin-ply hybrid laminates and out-of-autoclave tanks are projected for future space missions.Section VII: Clathrate HydratesChapter 7 (J. Lee and J. W. Kenney, III) In this chapter a brief historical review of the formation, structure, and uses of clathrate hydrates forms the backdrop for a discussion of modern scientific investigations of these solids employing spectroscopy, structure determination methods, isotopic studies, computational-theoretical modelling, and interrogations of guest-host interactions via special guests. For example, the use of colored halogens in clathrate hydrate hosts enables UV-visible spectroscopic methods to be employed to study clathrate hydrate structure.