Download or read book Investigation of the Oxidation Behavior of High Strength NiAl Alloys written by Arthur Lee Brown and published by . This book was released on 2008 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Oxidation and Corrosion of Intermetallic Alloys written by Gerhard Welsch and published by ASM International(OH). This book was released on 1996 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: This handbook provides researchers and development engineers with essential information on intermetallics for high temperature applications. The information will enable users to make choices by considering cost, properties, and performance for long-term use at elevated temperatures and in other adverse environmental conditions. It provides an overview of processing, structural and mechanical properties, applications, behavior and endurance at high temperature and in oxidizing conditions. It also focuses on 'pesting' disintegration, corrosion and oxidation phenomena at intermediate temperatures, corrosion embrittlement at ambient temperatures, aqueous corrosion and corrosion sensitive embrittlement properties.
Download or read book Microstructural Evolution and Oxidation Behavior of AlNiCrCoSi Multi component Alloys written by Joel Alfano and published by . This book was released on 2013 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: Equiatomic or near-equiatomic multicomponent alloys, often termed high-entropy alloys (HEAs), are an emerging class of metallic materials that are being investigated for a wide range of technical applications. Unlike conventional engineering alloys, HEAs lack a principal component and are instead composed of at least five major metallic elements, each with compositions generally ranging from 5 to 35 at. %. Unlike conventional alloys, HEAs have high entropies of mixing that are said to enhance the formation of solid solutions and other metastable phases resulting in materials exhibiting unique combinations of properties including high thermal stability, high strength/hardness, and high corrosion/oxidation resistance. Most studies of HEAs have focused on optimizing microstructures or mechanical properties. Relatively few have designed an alloy for or investigated oxidation behavior of HEAs. This dissertation describes the microstructural evolution and oxidation behavior of three HEA alloys that were designed with the intent to provide high oxidation resistance whilst offering the possibility for high temperature precipitation hardening. The alloys were intentionally designed to contain four elements that are commonly utilized in high temperature high-temperature Ni-based alloys, Al, Ni, Cr, and Co. A fifth element, Si, was also added. Though not a typical addition to structural Ni-based superalloys, it has been show to improve their resistance to oxidation, hot corrosion, and wear, particularly when incorporated into surface layers or protective coatings. All of the alloys investigated were designed using the phase selection rules proposed by Yang and Zhang which predicted that the alloys would consist of a mixture of solid solution and intermetallic phases in the as-cast or as-deposited state. Two alloys were designed to have higher concentrations of Al and Cr, thus maximizing the possibility of forming disordered BCC phases, while one was designed to have lower concentrations of Al and Cr, thus maximizing the chances of forming disordered FCC phases. Detailed microstructural and chemical analysis showed that characterizations have confirmed the presence of the expected solid solution phases, however, the majority phases in all of the alloys were found to be ordered intermetallics which increased in volume fraction upon annealing. The majority of the phases that formed were consistent with thermodynamic predications made using the Thermo-Calc software package; however the alloys were subject to phase transformations that could not be predicted using existing thermodynamic data. Isothermal and cyclic oxidation tests demonstrated that both sets of alloys were capable of forming aluminum oxide (aka alumina) surface scales, but that alloys containing higher Al and Cr were more stable. Coatings with similarly high Al and Cr levels were found to significantly improve the oxidation resistance of pure Ni and to exceed the 250 h oxidation upon the already excellent oxidation resistance of beta-NiAl based coatings. This result was surprising in that the HEA coatings produced in this study were thinner and were deposited on a less oxidation resistant substrate than the beta-NiAl based coatings. Collectively these results have confirmed that complex multicomponent HEAs that are capable of forming protective alumina scales can be designed and processed using existing phase selection rules. These results also reiterate the need for refinement of the phase selection rules for HEA formation and improved thermodynamic databases to facilitate the design of better HEAs.
Download or read book Thermodynamics Diffusion and the Kirkendall Effect in Solids written by Aloke Paul and published by Springer. This book was released on 2014-07-16 with total page 543 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book basic and some more advanced thermodynamics and phase as well as stability diagrams relevant for diffusion studies are introduced. Following, Fick’s laws of diffusion, atomic mechanisms, interdiffusion, intrinsic diffusion, tracer diffusion and the Kirkendall effect are discussed. Short circuit diffusion is explained in detail with an emphasis on grain boundary diffusion. Recent advances in the area of interdiffusion will be introduced. Interdiffusion in multi-component systems is also explained. Many practical examples will be given, such that researches working in this area can learn the practical evaluation of various diffusion parameters from experimental results. Large number of illustrations and experimental results are used to explain the subject. This book will be appealing for students, academicians, engineers and researchers in academic institutions, industry research and development laboratories.
Download or read book Nial Alloys for Structural Uses written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-10-20 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Alloys based on the intermetallic compound NiAl are of technological interest as high temperature structural alloys. These alloys possess a relatively low density, high melting temperature, good thermal conductivity, and (usually) good oxidation resistance. However, NiAl and NiAl-base alloys suffer from poor fracture resistance at low temperatures as well as inadequate creep strength at elevated temperatures. This research program explored macroalloying additions to NiAl-base alloys in order to identify possible alloying and processing routes which promote both low temperature fracture toughness and high temperature strength. Initial results from the study examined the additions of Fe, Co, and Hf on the microstructure, deformation, and fracture resistance of NiAl-based alloys. Of significance were the observations that the presence of the gamma-prime phase, based on Ni3Al, could enhance the fracture resistance if the gamma-prime were present as a continuous grain boundary film or 'necklace'; and the Ni-35Al-20Fe alloy was ductile in ribbon form despite a microstructure consisting solely of the B2 beta phase based on NiAl. The ductility inherent in the Ni-35Al-20Fe alloy was explored further in subsequent studies. Those results confirm the presence of ductility in the Ni-35Al-20Fe alloy after rapid cooling from 750 - 1000 C. However exposure at 550 C caused embrittlement; this was associated with an age-hardening reaction caused by the formation of Fe-rich precipitates. In contrast, to the Ni-35Al-20Fe alloy, exploratory research indicated that compositions in the range of Ni-35Al-12Fe retain the ordered B2 structure of NiAl, are ductile, and do not age-harden or embrittle after thermal exposure. Thus, our recent efforts have focused on the behavior of the Ni-35Al-12Fe alloy. A second parallel effort initiated in this program was to use an alternate processing technique, mechanical alloying, to improve the properties of NiAl-alloys. Mechanical alloying in the convent...
Download or read book Oxidation of Intermetallics written by Hans Jürgen Grabke and published by Wiley-VCH. This book was released on 2008-07-11 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the last ten years vast efforts were made in the research and development of intermetallic compounds to attain improved high temperature strength and low temperature ductility. These new structural materials are used in several high-temperature applications like engines and turbines. Oxidation and corrosion resistance are as important for the current applications of these materials as mechanical properties. This book gives a sound review of the present knowledge of the oxidation kinetics and mechanisms of intermetallics. Especially Ti-, Ni- and Fe-aluminides are treated in detail by experts from Europe, USA and Japan. The information provided will be of wealth for any engineer and scientist- materials scientist, physicist or chemist - involved in the development of new intermetallic materials and their applications.
Download or read book The 1200 C Cyclic Oxidation Behavior of Two Nickel aluminium Alloys Ni 3 Al and NiAl with Additions of Chromium Silicon and Titanium written by Carl E. Lowell and published by . This book was released on 1972 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High temperature Oxidation of Metals written by Per Kofstad and published by . This book was released on 1966 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physical and Mechanical Metallurgy of NiAl written by Ronald D. Noebe and published by . This book was released on 1994 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Considerable research has been performed on NiAl over the last decade, with an exponential increase in effort occurring over the last few years. This is due to interest in this material for electronic, catalytic, coating, and especially high-temperature structural applications. This report uses this wealth of new information to develop a complete description of the properties and processing of NiAl and NiAl-based materials.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1988 with total page 872 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Oxidation of High temperature Intermetallics written by Toni Grobstein and published by . This book was released on 1988 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advanced Characterization of the Oxidation Behavior of Grain Refined NiAl written by Rachel Ellen White and published by . This book was released on 2019 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reactive element doped Îø-NiAl is one of the most oxidation resistant materials available for high temperature use. It has been extensively studied to create the most adherent, slow growing, and passive layer possible. One recent area of interest is grain refinement, whereby the reduced metal grain size improves mechanical properties, transports reacting elements rapidly to the oxidizing surface, and facilitates the growth of a more adherent scale. This research focused on the effect of substrate grain refinement on the microstructure of its thermally grown oxide, in comparison to the oxide grown on extruded and single crystal NiAl alloys. The oxidation behavior of grain refined materials produced by via sputter deposition, ball milling, and cryomilling was found to vary significantly. Sputter deposition was shown to significantly increase the parabolic steady state oxidation rate constant, while decreasing the length of transient oxidation. Ball milling did not result in an increase in oxidation rate, but did show increased interfacial void formation as a result of the Al2O3 dispersions incorporated during the milling process. Last, cryomilling resulted in an increase in steady state oxidation rate and increased interfacial void formation that was correlated to AlN dispersions incorporated during milling. All three grain refinement methods were found to decrease the oxide grain size approximately three-fold in comparison with the oxide grown on extruded NiAl, though a consistent relationship between oxide grain size and steady state oxidation rate was not observed. This suggests that microstructural features other than substrate and oxide grain size dominate the oxidation behavior.
Download or read book NASA Technical Note written by and published by . This book was released on 1972 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book COSP for Windows Strategies for Rapid Analyses of Cyclic Oxidation Behavior written by James L. Smialek and published by . This book was released on 2002 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High Temperature Oxidation and Corrosion of Metals written by David John Young and published by Elsevier. This book was released on 2008-10-03 with total page 593 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book is concerned with understanding the fundamental mechanisms of high temperature alloy oxidation. It uses this understanding to develop methods of predicting oxidation rates and the way they change with temperature, gas chemistry and alloy composition. The focus is on designing (or selecting) alloy compositions which provide optimal resistance to attack by corrosive gases. . Emphasises quantitative calculations for predicting reaction rates and the effects of temperature, oxidant activities and alloy compositions. . Uses phase diagrams and diffusion paths to analyse and interpret scale structures and internal precipitation distributions . Provides a detailed examination of corrosion in industrial gases (water vapour effects, carburisation and metal dusting, sulphidation) . Text is well supported by numerous micrographs, phase diagrams and tabulations of relevant thermodynamic and kinetic data . Combines physical chemistry and materials science methodologies.
Download or read book Proceedings of the Symposium on Oxide Films on Metals and Alloys written by B. R. MacDougall and published by . This book was released on 1992 with total page 628 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Handbook of Aluminum written by George E. Totten and published by CRC Press. This book was released on 2003-04-25 with total page 744 pages. Available in PDF, EPUB and Kindle. Book excerpt: This reference provides thorough and in-depth coverage of the latest production and processing technologies encountered in the aluminum alloy industry, discussing current analytical methods for aluminum alloy characterization as well as extractive metallurgy, smelting, master alloy formation, and recycling. The Handbook of Aluminum: Volume 2 examin
