Download or read book Effects of Annealing Treatments on Superplasticity in a Thermomechanically Processed Aluminum 10 2 Mg 0 52 Mn written by A. F. Stengel and published by . This book was released on 1984 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research follows previous thesis work by Becker and Mills on superplastic behavior of a warm rolled Al-10.2%Mg-0.52%Mn alloy. Elongations of up to 391% were reported to them for tension testing at 300 C and a strain rate of .0014/s. In this work, material was warm rolled at 300 C to 94% reduction and then subjected to one of five subsequent annealing treatments: 1 hour at 200 C, 10 hours at 200 C, 1/2 hour at 250 C, 1 hour at 250 C, or 1/2 hour at 440 C (to recrystallize the material). Tension testing at temperatures ranging from 300 C to 425 C was then conducted. Annealing below the rolling temperature enhances superplastic behavior when compared to the as rolled condition. For example, material warm rolled at 300 C with a strain rate of .0056/s gave a ductility of 572%. Annealing, however, for 1/2 hour at 440 C results in a recrystallized structure which is stronger than the as-rolled condition and less ductile when tested at 300 C. Originator's supplied keywords include: aluminum, aluminum-magnesium, grain refinement, precipitation, cavitation, grain boundary sliding.
Download or read book Effects of Annealing Treatments on Superplasticity in a Thermomechanically Processed Aluminum 10 2 Mg 0 52 Mn Alloy written by Alta Fern Stengel and published by . This book was released on 1984 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Superplasticity in a Thermo Mechanically Processed Aluminum 10 2 Mg 0 52 Mn Alloy written by Max E. Mills and published by . This book was released on 1984 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book The Effect of Alloy Additions on Superplasticity in Thermomechanically Processed High Magnesium Aluminum Magnesium Alloys written by R. J. Self and published by . This book was released on 1984 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Alloys Index written by and published by . This book was released on 1985 with total page 1000 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 1987 with total page 786 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1985 with total page 590 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of Processing and Superplastic Deformation on Ambient Ductility of Al 10 Mg 0 1 Zr written by Dimosthenis K. Solomos and published by . This book was released on 1987 with total page 87 pages. Available in PDF, EPUB and Kindle. Book excerpt: In previous work, the room temperature mechanical properties of an Al-10Mg-0.1Zr alloy were evaluated after simulated, superplastic forming at a temperature of 300 C (573K). A variation of ductility from 1 to 14% elongation was observed in the room temperature test data. To examine the cause of this variability, the processing schedule was changed to one incorporating more severe reductions during rolling. This resulted in a lesser range of variability in room temperature ductility, but the material no longe behaved superplastically. Elongations at 300 C of only 161% at a maximum were recorded although the small grain size required for good superplasticity apparently was developed. SEM and optical microscopy was then done to investigate the cause of this loss of superplastic behavior. Keywords: Superplasticity, Ductility, Aluminum magnesium, Alloys, thermomechanical, Processing, Aluminum alloys.
Download or read book Analysis of Grain Refinement and Superplasticity in Aluminum Magnesium Alloys written by Ahmed Ahmed Abou-Salama and published by . This book was released on 1987 with total page 167 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Processing of 2090 Aluminum Alloy for Superplasticity written by and published by . This book was released on 1988 with total page 71 pages. Available in PDF, EPUB and Kindle. Book excerpt: The applicability of a thermomechanical process, involving warm rolling to facilitate continuous recrystallization (CRX), to aluminum alloy 2090 was considered. The thermomechanical process has been shown to result in 2-5mm grains and superplasticity at 300C in Al-Mg and Al-Mg-Li alloys. In this study, the warm rolling temperature and the reheating time between consecutive rolling passes were varied. Superplastic ductility of 320 percent was obtained during tension testing at 350C. Microstructural analysis of the structures produced during warm rolling indicates inadequate interaction between precipitating phases and dislocation structures. Thus, improved warm-temperature superplastic ductility may be obtained by initial precipitation treatments followed by warm rolling. Keywords: Aluminum-Copper Lithium alloys 2090; Thermomechanically processing; Superplasticity. (jes).
Download or read book Thermomechanical Processing of Aluminum Alloy 2090 for Superplasticity written by MoHammad B. Choudhry and published by . This book was released on 1989 with total page 85 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effect of processing variables on the microstructural development and superplasticity of aluminum alloy 2090, a high strength Aluminum-Copper-Lithium-Zirconium alloy of reduced density in comparison to other A1-based materials, was investigated. Following previous research, warm rolling was conducted to strains, up to 3.36 and it was found that increasing the strain to values greater than 2.6 offered no improvement in subsequent superplastic response. Increased rolling speeds likewise did not enhance ductibility above a maximum value of approximately 240 percent. Microstructural examination revealed a refined, homogeneous microstructure consisting of T2 particles distributed in an alloy matrix. These particles reside a triple junctions in a recovered microstructure. Theses. (AW).
Download or read book Study of Processing and Microstructure of a Superplastic 5083 Aluminum Alloy written by Tracy A. Maestas and published by . This book was released on 2002-09 with total page 77 pages. Available in PDF, EPUB and Kindle. Book excerpt: Orientation Imaging Microscopy (OIM) methods were applied to the analysis of the microstructure and microtexture as well as the deformation and failure modes of superplastic AA5083 aluminum alloys. Annealing of a cold-rolled AA5083 material at 450 deg C resulted in the formation of equiaxed grains approximately 7mum-8mum in size. Random grain-to-grain misorientations were consistent with particle-stimulated nucleation of recrystallization during processing for superplasticity. Such as microstructure is necessary for superplasticity but mechanical property data indicated only moderate ductility and failure by cavity formation and linkage. This investigation then employed OIM methods to identify the misorientations of boundaries prone to cavitation and determine the role of such boundaries in failure of these materials during elevated temperature deformation.
Download or read book Metals Abstracts written by and published by . This book was released on 1997 with total page 782 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thermomechanical Processing of Aluminum Alloy 2519 for Grain Refinement and Superplasticity written by Scott D. Bohman and published by . This book was released on 1992 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Annual Index written by and published by . This book was released on 1985 with total page 974 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Superplasticity at High Strain Rates in Aluminum Alloys written by and published by . This book was released on 1996 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: The detailed experimental data of microstructural developments during the optimum thermomechanical treatments and superplastic properties in the wide deformation range have been investigated on fourteen P/M aluminum alloys with various chemical matrix compositions and different typed precipitate particles. It was revealed that the differences in both size and volume among the second phase particles, which increase with content of Zr, Cr, Mn or Y, affect on the recrystallization behavior, grain size and superplastic properties of these aluminum alloys. Some of them exhibited high-strain-rate superplasticity, so the optimizing processing methods in this proposal were very powerful to provide the desired structures required for high-strain-rate superplasticity in these aluminum alloys. A theoretical interpretation, based on the experimental data by tensile test and the observed grain sizes, has been revealed that values in activation energy for all alloysare between 140 and 155 kJmol-1, which are similar to that for lattice self-diffusion of aluminum. Each mechanical data of each alloy can be presented by a single equation. It was postulated that superplastic flow in these P/M aluminum alloys was fundamentally controlled by a grain boundary sliding mechanism accommodated by dislocation climb controlled by lattice self-diffusion. However, for the statically recrystallized alloys consisted of the high-angle grain boundaries, the Dorn typed equation presents n=2, p=2 and D=D sub L, whereas for the dynamically recrystallized alloys with the low-angle grain boundaries, n=3, p=2 and D=D sub L. The consideration for deformation mechanisms with the accommodation helper by such a liquid has been applied on the aluminum alloys, but it remained unclear.
Download or read book Grain Boundary Development in Superplastic Aluminum Alloys written by Michael Edward McMahon and published by . This book was released on 1996-12-01 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: Superplasticity may be defined as the capability of certain polycrystalline materials to deform to extensive plastic elongations prior to failure, often without formation of a neck. Typically, superplasticity refers to tensile elongations greater than 200%, although some elongations have been reported in excess of 5000% Ref 1. While it has been suggested that bronze metals in use in ancient civilizations may have possessed superplastic properties Ref 2, most historical reviews credit the modern-day documentation of superplastic behavior to a paper published in the Journal of the Institute of Metals by G.D. Bengough in 1912 which described extensive elongations in brass Ref 3. Recognition of a stress and strain-rate relationship was first presented qualitatively in a paper by Rosenhain in 1920 which examined a near eutectic Zn- Al-Cu alloy Ref 4. Photomicrographs detailing superplastic grain structures in eutectic Sn-Pb and Bi-Pb alloys deformed to elongations of 2000% were presented in 1934 by Pearson Ref 5. This study was the first to identify an equiaxed grain morphology in the deformed regions and suggest that grain boundary migration may be involved in the deformation processes.
