Download or read book The Role of Ledge Nucleation Migration in Omega Plate Thickening Behavior in Al Cu Mg Ag Alloys written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The thickening kinetics of[Omega] plates in an Al-4Cu-0.3Mg-0.2Ag (wt.%) alloy have been measured at 200 C, 250 C and 300 C using conventional transmission electron microscopy techniques. At all temperatures examined the thickening showed a linear dependence on time. At 200 C the plates remained less than 6nm in thickness after 1000h exposure. At temperatures above 200 C the thickening kinetics are greatly increased. Atomic resolution Z-contrast microscopy has been used to examine the structure and chemistry of the (001)[sub[Omega]][parallel] (111)[sub[alpha]] interphase boundary in samples treated at each temperature. In all cases, two atomic layers of Ag and Mg segregation were found at the broad face of the plate. The risers of the growth ledges and the ends of the plates were free of segregation. No significant levels of Ag or Mg were detected inside the plate at any time. The necessary redistribution of Ag and Mg accompanying a migrating thickening ledge occurs at all temperatures and is not considered to play a decisive role in the excellent coarsening resistance exhibited by the[Omega] plates at temperatures up to 200 C. Plates transformed at 200 C rarely contained ledges and usually exhibited a strong vacancy misfit normal to the plate. A large increase in ledge density was observed on plates transformed at 300 C, concomitant with accelerated plate thickening kinetics. The high resistance to plate coarsening exhibited by[Omega] plates at temperatures up to 200 C, is due to limited ledge nucleation under these conditions. The prohibitively high barrier to coherent ledge nucleation on the broad faces of plates aged at 200 C arises from the contribution to the total free energy change attending nucleation from elastic interactions between the misfitting coherent ledges and the significant strain field that can exist normal to the broad face of the[Omega] plate.
Download or read book Characterization of Al Cu Mg Ag Alloy RX226 T8 Plate written by Cynthia L. Lach and published by . This book was released on 2003 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Alloy Development for the Enhanced Stability of omega Precipitates in AL CU MG AG Alloys written by Brian M. Gable and published by . This book was released on 2004 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Microstructure and Aging Behavior of Conventional and Nanocrystalline Al Cu Mg Alloys with Sc Additions written by Alejandro Zúñiga and published by . This book was released on 2006 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Characterization of Al Cu Mg AG Alloy Rx226 T8 Plate written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-05-29 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aluminum-copper-magnesium-silver (Al-Cu-Mg-Ag) alloys that were developed for thermal stability also offer attractive ambient temperature strength-toughness combinations, and therefore, can be considered for a broad range of airframe structural applications. The current study evaluated Al-Cu-Mg-Ag alloy RX226-T8 in plate gages and compared performance with sheet gage alloys of similar composition. Uniaxial tensile properties, plane strain initiation fracture toughness, and plane stress tearing resistance of RX226-T8 were examined at ambient temperature as a function of orientation and thickness location in the plate. Properties were measured near the surface and at the mid-plane of the plate. Tensile strengths were essentially isotropic, with variations in yield and ultimate tensile strengths of less than 2% as a function of orientation and through-thickness location. However, ductility varied by more than 15% with orientation. Fracture toughness was generally higher at the mid-plane and greater for the L-T orientation, although the differences were small near the surface of the plate. Metallurgical analysis indicated that the microstructure was primarily recrystallized with weak texture and was uniform through the plate with the exception of a fine-grained layer near the surface of the plate. Scanning electron microscope analysis revealed Al-Cu-Mg second phase particles which varied in composition and were primarily located on grain boundaries parallel to the rolling direction. Fractography of toughness specimens for both plate locations and orientations revealed that fracture occurred predominantly by transgranular microvoid coalescence. Introduction High-strength, low-density Al-Cu-Mg-Ag alloys were initially developed to replace conventional 2000 (Al-Cu-Mg) and 7000 (Al-Zn-Cu-Mg) series aluminum alloys for aircraft structural applications [1]. During the High Speed Civil Transport (HSCT) program, improvements in thermal stability were demonstrated for candidate
Download or read book The Influence of Spray Deposition Processing on the Microstructure and Mechanical Behavior of Al Cu Mg Ag Alloys written by Linda Del Castillo and published by . This book was released on 2000 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optimizing Mechanical Properties and Thermal Stability of Age Hardenable Aluminum Alloys Through Theoretical Modeling Alloy Modification and Thermal Mechanical Processing written by and published by . This book was released on 2005 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: This proposal was to design and test an Al-Cu-Mg (Ag) alloy for moderate temperatures (up to 150 degrees C) application. A significant improvement in the creep resistance was primarily pursued in the program through enhancement of the yield strength and the thermal stability of the age-hardenable alloy. Major tasks have been finished as planned: 1) We identified the optimum structures of complex multiple secondary phase precipitates using dislocation slip simulation methods that we developed; focusing on Al-Cu-Mg based alloys with Cu: Mg ratios, vs. determined the omega phase as the main strengthening precipitate phase. 2) We constructed a special thermodynamic database (incorporating the metastable omega phase) to determine the absolute Cu and Mg concentration for optimum chemical driving forces of omega phase nucleation. 3) To control the formation (nucleation) of competing precipitate phases, we developed an effective and efficient approach to characterize effects of alloying elements. The computational tools, combining the state-of-the- art across-scale computational methods from first principles calculations to clustering strain analysis. We demonstrated how trace amounts of Mg and Ag additional catalyze omega phase nucleation and identified Si to be deleterious and that it must be eliminated. 4) We accordingly designed new alloys with compositions: Al -(4 to 5) Cu-(O.4 to 0.6) Mg-(O.4 to 0.06) Ag (wt%)with minimal Si content for the optimum strength and second phase thermal stabilities.
Download or read book Microstructure property Relationships in Al Cu Li Ag Mg Weldalite superscript TM Alloys written by T. J. Lanagan and published by . This book was released on 1991 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An In Situ HRTEM Study of Growth Mechanisms of the 111 Precipitate Plate in Al Cu Mg Ag Alloys written by William Earl Benson and published by . This book was released on 1995 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Microstructural Evolution During Aging of an Al Cu Li Ag Mg Zr Alloy written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-08-20 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Alloys in the Al-Cu-Li Ag-Mg subsystem were developed that exhibit desirable combinations of strength and ductility. These Weldalite (trademark) alloys, are unique for Al-Cu-Li alloys in that with or without a prior cold stretching operation, they obtain excellent strength-ductility combinations upon natural and artificial aging. This is significant because it enables complex, near-net shape products such as forgings and super plastically formed parts to be heat treated to ultra-high strengths. On the other hand, commercial extrusions, rolled plates and sheets of other Al-Cu-Li alloys are typically subjected to a cold stretching operation before artificial aging to the highest strength tempers to introduce dislocations that provide low-energy nucleation sites for strengthening precipitates such as the T(sub 1) phase. The variation in yield strength (YS) with Li content in the near-peak aged condition for these Weldalite (trademark) alloys and the associated microstructures were examined, and the results are discussed. Kumar, K. S. and Brown, S. A. and Pickens, Joseph R. Unspecified Center ...
Download or read book Role of Nucleation Entropy in Precipitation in Al Cu Alloy microform written by J. Karov and published by National Library of Canada. This book was released on 1985 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Light Alloys written by Ian Polmear and published by Elsevier. This book was released on 2005-11-11 with total page 437 pages. Available in PDF, EPUB and Kindle. Book excerpt: The definitive overview of the science and metallurgy of aluminum, magnesium, titanium and beryllium alloys, this is the only book available covering the background materials science, properties, manufacturing processes and applications of these key engineering metals in a single accessible volume. Use of these metals is now more widespread than ever, and they are routinely found in motor vehicles and aircraft. New material includes materials characteristics and applications; heat treatment properties; fabrication; microstructure/property relationships; new applications and processes. The definitive single volume overview New material on processing, characteristics and applications of these essential metals Covers the latest applications and processes in the auto and aero industries
Download or read book Titanium and Titanium Alloys written by Christoph Leyens and published by John Wiley & Sons. This book was released on 2006-03-06 with total page 532 pages. Available in PDF, EPUB and Kindle. Book excerpt: This handbook is an excellent reference for materials scientists and engineers needing to gain more knowledge about these engineering materials. Following introductory chapters on the fundamental materials properties of titanium, readers will find comprehensive descriptions of the development, processing and properties of modern titanium alloys. There then follows detailed discussion of the applications of titanium and its alloys in aerospace, medicine, energy and automotive technology.
Download or read book Liquid Cell Electron Microscopy written by Frances M. Ross and published by Cambridge University Press. This book was released on 2017 with total page 529 pages. Available in PDF, EPUB and Kindle. Book excerpt: 2.6.2 Electrodes for Electrochemistry
Download or read book Current Trends in Boriding written by Michal Kulka and published by Springer. This book was released on 2018-12-30 with total page 293 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the most important thermochemical and physical techniques of boriding. The formation and characterization of different boride layers or boride coatings are compared in this book. The author analyzes the technological aspects of boriding processes, presenting the advantages and disadvantages of each method. The effect of the boriding techniques on the microstructure of borided materials are also indicated. The mechanism of formation of active boron atoms or ions and the phenomena during re-melting of alloying material together with the substrate are described. Special attention is devoted to powder-pack boriding, electrochemical boriding in borax, gas boriding, plasma gas or paste boriding and laser or plasma surface alloying with boron, acknowledged as the most important current methods in boriding. The thermodynamics of gas boriding is also analyzed.
Download or read book Surface Chemistry and Catalysis written by Albert F. Carley and published by Springer Science & Business Media. This book was released on 2002-09-30 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt: Exciting results are still emerging from the many research groups working in this fertile area and the book is an excellent stimulus to researchers at the start of the 21st century."--BOOK JACKET.
Download or read book Solidification Processing of Metallic Alloys Under External Fields written by Dmitry G. Eskin and published by Springer. This book was released on 2018-10-09 with total page 323 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explores the application of external physical fields to the solidification processing of metallic alloys. Leading academics from around the world present comprehensive and critical reviews on state-of-the-art research and discuss possible future directions. Major physical fields, including electromagnetic, electric, acoustic, and thermal, are considered. In addition, the most advanced synchrotron X-ray based real-time and in-situ studies and numerical modeling methodologies are reviewed and discussed, with a special emphasis on their applications to the solidification processes. Throughout, all chapters are illustrated with both historical and very recent research cases, including typical examples of in-situ studies, modeling, and simulation. This book contains essential knowledge and information suitable for a wide audience, from undergraduate and postgraduate students to academics, practicing researchers, and engineers in materials, metallurgy, and manufacturing.
