Author: R. J. Self
Publisher:
ISBN:
Category :
Languages : en
Pages : 127
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Book Description
This research extends previous thesis work by Becker and Mills, and is concurrent with that of Stengel on the superplastic behavior of warm rolled high-Mg, Al-Mg alloys. In this work, the effect of various alloy additions were investigated. The following Al-Mg alloy compositions were studied: 8% Mg; 8% Mg-0.4% Cu; 8% Mg-0.4% Cu-0.5% Mn; 10% Mg; 10% Mg-0.4% Cu; 10% Mg-0.2% Mn. These materials were solution treated and hot worked at 440 C and then warm rolled at 300 C to 94% reduction. Tensile testing was then conducted for the as-rolled condition. The alloys were tested at temperatures ranging from room temperature to 300 C and at strain rates from .000056/sec to .14/sec. The copper addition has, on the same weight percentage basis, the same effect on superplasticity as does the addition of manganese to the alloy. The addition of small amounts (i.e., approximately 0.2 weight percent) of manganese appears to offer little advantage over the binary compositions in terms of super plasticity.
Author: J. J. Becker
Publisher:
ISBN:
Category :
Languages : en
Pages : 102
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Book Description
The elevated temperature deformation characteristics of two thermomechanically processed high magnesium, aluminum-magnesium alloys were investigated. The thermomechanical processing itself included warm rolling at 300 deg C to 94% reduction. Subsequent treatments included annealing after rolling for either one-half hour or ten hours at 300 deg C, or one half hour at 440 deg C. These annealing treatments resulted in varying degrees of recrystallization and grain growth and facilitated examination of the effect of grain size on the superplastic deformation characteristics of these alloys. Tension testing was conducted at strain rates ranging from .000053 to .053 S-1 and temperatures varying from ambient to 300 deg C. Materials in the warm rolled condition exhibited the highest strength at ambient temperature and were generally most superplastic at elevated temperature. An Al 10%Mg-0.5%Mn alloy exhibited elongation of approximately 400% at 300 deg C.
Author: Ralph Brian Johnson
Publisher:
ISBN:
Category :
Languages : en
Pages : 90
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Book Description
The purpose of this research was the development of a thermomechanical procedure to process Aluminum-Magnesium alloys and testing effects of alloying additions on these alloys. Magnesium contents of eight and ten weight percent and the alloying effects of copper and manganese were studied. Microstructures and mechanical properties at six warm rolling temperatures located above and below the solvus line of these alloys were examined. Ultimate tensile strengths in excess of 680 MPa (99 KSI) were obtained. Microstructural evidence indicated that the precipitation of the 'beta' intermetallic phase was one of the most important mechanisms in controlling the strength of the alloy. Furthermore, precipitation is so rapid at higher temperatures that it becomes the strongest force within the microstructure and its presence prevents any possible recrystallization of the alloy. However, when the temperature exceeds the solvus temperature for the alloy, recrystallization does occur with large losses in both yield and ultimate tensile strength. (Author).
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 704
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Author: Wade H. Shafer
Publisher: Springer Science & Business Media
ISBN: 1461573882
Category : Science
Languages : en
Pages : 414
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Book Description
Masters Theses in the Pure and Applied Sciences was first conceived, published, SIld disseminated by the Center for Information and Numerical Data Analysis and Synthesis (CINDAS) * at Purdue University in 1957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dissemination phases of the activity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thought that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all con cerned if the printing and distribution of the volumes were handled by an interna and broader dissemination. tional publishing house to assure improved service Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Cor poration of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 30 (thesis year 1985) a total of 12,400 theses titles from 26 Canadian and 186 United States universities. We are sure that this broader base for these titles reported will greatly enhance the value of this important annual reference work.
Author: Ahmed Ahmed Abou-Salama
Publisher:
ISBN:
Category :
Languages : en
Pages : 167
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Book Description
Previous research had demonstrated superplastic behavior in aluminum-magnesium alloys of high magnesium content to result from deformation processing to an initially non recrystallized condition. Analysis here of those data has demonstrated that such a result may be understood in terms of constitutive equations developed for fine-grained materials and that the constitutive equations are applicable to materials achieving grain boundary misorientations in the range of only 2 to 7 by a process of continuous recrystallization. The constitutive equations provide a basis for analysis of anomalous temperature dependence of the strength and of the activation energy for plastic deformation seen as well in this work. A study of the separate effects of processing variables has lead to a model for continuous recrystallization during deformation processing. This model considers recovery of dislocations to sub-boundaries to be the critical step in this process. Application of this model to development of advanced aluminum alloys for air frame structural applications will result in increased weight savings by such processing methods. Theses Keywords: Superplasticity; Aluminum magnesium alloys; Thermomechanical processing; Microstructural evolution; Continuous recrystallization; Microstructural instability; Grain growth.
Author: Max E. Mills
Publisher:
ISBN:
Category : Mechanical engineering
Languages : en
Pages : 0
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Book Description
This research extended the previous work performed by Becker on the elevated temperature deformation characteristics of an aluminum-10.2% magnesium-0.52% manganese alloy. The alloy was warm rolled at 300 C to 94% reduction. Stress-strain testing was utilized to collect data for stress vs strain rate and ductility vs strain rate, as well as, stress exponents and activation energies. Tensile testing was performed at strain rates at .000139 per sec. and temperatures from 20 C to 425 C. Ductility ranged from 400% at 300 C and 600% at 325 C to 700% at 425 C. The data clearly establishes that the warm rolled alloy is superplastic at temperatures as low as 275 C and may exhibit superplastic elongations (greater than 400%) at strain rates at high as .01 per sec at 325 C. Scanning electron microscope observations indicated little or no void formation at or below 300 C. The high ductilities observed at temperatures above the solvus are the result of grain boundary sliding. Originator-supplied keywords included: Superplasticity, Aluminum, Aluminum alloys, Aluminum-magnesium, Thermo-mechanical processing, Rolling, Warm rolling, Annealing recrystallization, Grain Refinement, Precipitation, Cavitation, Grain boundary sliding, Computer programs, Fortran, Theses.
Author: Fusheng Pan
Publisher: Elsevier
ISBN: 0128201118
Category : Technology & Engineering
Languages : en
Pages : 309
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Book Description
High Plasticity Magnesium Alloys focuses on the microstructure, mechanical properties and processing methods of magnesium alloy materials. The title offers theory and methods on high-plasticity magnesium alloys, including phase diagram construction, alloying and deformation. Four typical high-plasticity magnesium alloys are discussed through thermodynamic phase diagram construction and the characterization of their microstructure, mechanical properties and texture at as-cast, extruded, rolled and heat-treated states. Chapters update principle calculations for the effects of alloying elements, Mg-Gd-Zr medium strength and high-plasticity alloys, medium strength and high-plasticity Mg-Mn based alloys, medium strength and high-plasticity Mc-Sn based alloys, and Mg-Gd-Y-Zn-Mn high-strength and high-plasticity magnesium alloys. This book presents the plasticity of magnesium alloys, and guides the design and development of new high-strength and high-plasticity magnesium alloys. It provides detailed solutions for practicing industrial engineers. - Presents in-depth theory and research methods on high-plasticity magnesium alloys - Considers the microstructure, mechanical properties and processing methods of high-performance magnesium alloys - Shows the first principles needed to calculate the effects of various alloying elements - Introduces the development of magnesium alloys with relatively high plasticity - Characterizes the plasticity of polycrystalline metallic materials - Provides detailed solutions for industrial engineers who need to use high-performance magnesium alloys
Author: Raymond Arthur Grandon
Publisher:
ISBN:
Category :
Languages : en
Pages : 73
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Book Description
Microstructures and mechanical properties of thermomechanically processed Aluminum-Magnesium alloys were investigated in this research. Magnesium content of the alloys ranged from 7 to 12 weight percent and an alloy containing 10 percent Mg and 0.5 percent Cu was also examined. Thermomechanical processing treatments involved solution treatment followed by warm isothermal rolling. Temperature for this warm rolling was typically 300 C, and this is below the solvus temperature for the alloy. Such processing results in a fine dispersion of the intermetallic compound Al3Mg2 (beta) in a solid solution matrix. Typical mechanical properties are an ultimate tensile strength of 520 Mpa (75000 psi), with 12 percent elongation to fracture. Such a material may be further cold worked to ultimate tensile strengths of 620 Mpa (90000 psi), with 6 percent elongation to fracture. Dynamic recrystallization is necessary to achieve a uniform dispersion of the intermetallic in subsequent processing. (Author).
Author: John J. Becker
Publisher:
ISBN:
Category : Mechanical engineering
Languages : en
Pages :
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Book Description
