Download or read book The Morphological Development and Mechanical and Thermal Behavior of Powder Processed Icosahedral Phase Strengthened Aluminum Alloys written by Hannah Leonard and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quasicrystalline (QC) phases are a promising potential strengthening component in next generation Al-based metal matrix composites (MMCs). This thesis presents an investigation of a series of three gas atomized Al-based QC MMCs in the Al-Cr-Mn-Co-Zr system currently in development as a structural material for aerospace applications. All three alloys exhibited the same main phases (FCC Al and I-phase), but the microstructures contained three distinct types of I-phase morphologies and distributions that depended on powder particle size, and hence on the cooling rate and nucleation mechanisms. These microstructures were retained in the as-consolidated material, and after warm (300 - 370°C) uniaxial upset forging to 30 and 50% reduction, while forging to higher upsets gave a more refined and homogeneous microstructure. Tensile tests performed on the upset-forged alloys showed retention of yield and ultimate tensile strengths across the window of processing conditions, and an analysis of possible contributions from various strengthening mechanisms indicated that these mechanical properties arise from a combination of I-phase dispersion strengthening and solid solution strengthening due to supersaturation of Cr and Mn in the FCC Al matrix. Upon heat treatment, the consolidated alloy retained the initial hardness and microstructure up to about 400°C. Initial softening behavior after thermal exposures corresponded to the formation of a plate-like ternary Al11(Cr,Mn)2 phase within the former supersaturated Al matrix. Kinetic data from in situ TEM experiments on powder particles with the cellular dendritic microstructure gave an activation energy of 277 kJ/mol, consistent with Cr diffusion in the Al matrix being the rate-limiting process. Further heat-treatment resulted in a morphological change of the I-phase dispersoids, and TEM analysis identified that I-phase decomposed into a ternary Al45(Cr, Mn)7 and a Al9Co2 phase. Kissinger analysis of DSC data gave an activation energy of 162 kJ/mol, indicating a transformation initiated by Co diffusion. In situ STEM heating experiments on samples prepared from powder particles revealed the formation of Al9Co2 precipitates that coincided with the transformation of the I-phase. The structure-property relationships explored in this thesis work will be used as a basis for future development of these Al-based QC MMC materials.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1991 with total page 1460 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book Metals Abstracts written by and published by . This book was released on 1996 with total page 1628 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 Study on Effects of Powder and Flake Chemistry and Morphology on the Properties of Al Cu Mg X X X Powder Metallurgy Advanced Aluminum Alloys written by and published by . This book was released on 1986 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physics Briefs written by and published by . This book was released on 1993 with total page 1058 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanical Behavior of Ultrafine Dispersion Strengthened Aluminum Alloys written by Xinlin Shi and published by . This book was released on 2005 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Crystallization of amorphous alloys provides opportunities to produce bulk nanostructured materials with a high volume fraction of second phase particles. In this research, the deformation behavior of aluminum alloys with different alloying elements was characterized. The as-received materials were processed by powder metallurgy techniques. Extrusion was the secondary fabrication route to produce bulk materials"--Abstract, leaf iv.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1990 with total page 892 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1997 with total page 940 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Metals Abstracts Index written by and published by . This book was released on 1996 with total page 1622 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 Properties written by and published by . This book was released on 2003 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research was concerned with a practical approach to the design of an improved age-hardenable aluminum alloy for moderate temperature application. The process involved extensive empirical research, theoretical simulation and modeling, calculated phase diagrams and first principle calculations and analytical techniques. Microstructure characterization and analytical transmission electron microscopy were employed to refine the development of the quaternary Al-Cu-Mg-Ag phase diagram Differential scanning calorimetry and electron diffraction were implemented to investigate the microstructural evolution of the ternary alloys and to validate calculated equilibrium phase boundaries. Energy dispersive spectroscopy was also used to illustrate the effect of trace additions on the phase boundaries that are important for the thermal stability of this class of alloys. Computer simulation & modeling were used to identify the microstructure that will result in the optimal combination of mechanical properties. Unavailable parameters were calculated from first principle atomistic modeling. The major objective of this research program has been to illustrate the use of modeling and simulation in alloy design and therefore aid in the early insertion of new high performance materials.
Download or read book Aerospace Alloys written by Stefano Gialanella and published by Springer Nature. This book was released on 2019-10-30 with total page 583 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents an up-to-date overview on the main classes of metallic materials currently used in aeronautical structures and propulsion engines and discusses other materials of potential interest for structural aerospace applications. The coverage encompasses light alloys such as aluminum-, magnesium-, and titanium-based alloys, including titanium aluminides; steels; superalloys; oxide dispersion strengthened alloys; refractory alloys; and related systems such as laminate composites. In each chapter, materials properties and relevant technological aspects, including processing, are presented. Individual chapters focus on coatings for gas turbine engines and hot corrosion of alloys and coatings. Readers will also find consideration of applications in aerospace-related fields. The book takes full account of the impact of energy saving and environmental issues on materials development, reflecting the major shifts that have occurred in the motivations guiding research efforts into the development of new materials systems. Aerospace Alloys will be a valuable reference for graduate students on materials science and engineering courses and will also provide useful information for engineers working in the aerospace, metallurgical, and energy production industries.
Download or read book Metallurgical Transactions written by and published by . This book was released on 1990 with total page 1148 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Fundamental Study of P M Processed Elevated Temperature Aluminum Alloys written by M. J. Koczak and published by . This book was released on 1987 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: Al-Fe-Ni powder containing 0.19 volume fraction of FeNiA19 dispersoid (approx. 0.18 micrometers) was mechanically alloyed (MA) and hot extruded. There is a significant enhancement in creep response compared to the same alloy without MA and microstructural stability is superior. Improvements in creep strength and microstructural stability are attributed to the presence of fine-scale (approx. 30nm) oxides/carbides introduced during MA distributed uniformly throughout the martix, at matrix-intermetallic interfaces, and on subgrain boundaries. The fine-scale dispersion inhibits coarsening and appears to interact with the diffusing Fe and Ni atoms. Keywords: Aluminum, Iron, Nickel, Alloys, Powder metallurgy, Rapid solidification, Mechanical alloying, Microstructure, Stability, Temperature, Mechanical properties, Dispersion, Strengthening.
Download or read book The Effects of Powder Metallurgical Processing and Intermediate Thermal Mechanical Treatment on the Fatigue Properties of High Strength Aluminum Alloys X7091 written by Victor Wei-Chung Kuo and published by . This book was released on 1981 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effects of Powder Metallurgical Processing and Intermediate Thermal Mechanical Treatment on the Fatigue Properties of High Strength Aluminum Alloys written by Saghana Baran Chakrabortty and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effects of Powder Metallurgical Processing and Intermediate Thermal Mechanical Treatment on the Fatigue Properties of High Strength Aluminum Alloys written by Victor Kuo and published by . This book was released on 1983 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: The application of advanced metallurgical processing techniques, e.g., intermediate thermomechanical treatment (ITMT) and powder metallurgy (P/M), has produced a recrystallized X7091 P/M alloy having fine grain and particle structures and weak texture with the best overall mechanical properties compared to those of ingot metallurgical and conventional P/M alloys. The dependence of mechanical properties on grain size and particle distribution has been demonstrated among these alloys. The study of the effect of the last microstructural feature, crystallographic texture, is necessary for further property improvement through texture control.
