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An Approach To Low Temperature High Strain Rate Superplasticity In Aluminum Alloy 2090
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Book Synopsis An Approach to Low Temperature High Strain Rate Superplasticity in Aluminum Alloy 2090 by : Michael Wayne Reedy
Download or read book An Approach to Low Temperature High Strain Rate Superplasticity in Aluminum Alloy 2090 written by Michael Wayne Reedy and published by . This book was released on 1989 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Low-Temperature Superplasticity in Aluminum Alloys Processed by Equal-Channel Angular Pressing by :
Download or read book Low-Temperature Superplasticity in Aluminum Alloys Processed by Equal-Channel Angular Pressing written by and published by . This book was released on 2002 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: Equal-channel angular pressing (ECAP) was applied to achieve grain refinement of Al-3 mass%Mg alloys containing 0.2 mass%Sc. 0.2 mass%Fe or 0.1 mass%Zn The thermal stability of the fine-grained structures was examined by conducting static annealing experiments. The fine grain sizes produced by ECAP were essentially retained up to a temperature of 523K for the Fe-containing and Zr-containing alloys and up to a temperature as high as 773 K for the Sc-containing alloy. The three alloys with Sc. Fe and Zr additions were pulled to failure in tension at 523 K corresponding to 0.59Tm. where Tm is the absolute melting point of the alloy, and maximum elongations of 640%, 370% and 390% were obtained at an initial strain rate of 3.3 x l0-4 s-1 respectively. Such elongations resulted in more than three times or approximately twice the elongation achieved in a binary Al-3%M alloy. It is shown that either Fe or Zr may be used as an alternative element in place of Sc to attain low temperature superplasticity. Tensile testing was also conducted on the Sc-containing ternary alloy at a temperature as low as 473K corresponding to O.54Tm. A maximum elongation of 420% was attained at an initial strain rate of 3.3 % l0-4 s-1. This appears to be the lowest homologous temperature reported to date for superplasticity of Al-based alloys.
Book Synopsis Technical Reports Awareness Circular : TRAC. by :
Download or read book Technical Reports Awareness Circular : TRAC. written by and published by . This book was released on 1989-11 with total page 506 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Superplasticity in Aluminum Alloys by :
Download or read book Superplasticity in Aluminum Alloys written by and published by . This book was released on 1997 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have characterized in the Al-Mg system the microstructure and mechanical properties of a cold-rolled Al-6Mg-0.3Sc alloy. The alloy exhibited superplasticity at relatively high strain rates (about 10-2 s-1). At a strain rate of 10-2 s-1 there exists a wide temperature range (475-520'C) within which the tensile elongation is over 1000%. There also exists a wide strain rate range (10-3 - 10-1 s-1) within which the tensile elongation is over 500%. The presence of Sc in the alloy results in a uniform distribution of fine coherent Al3SC precipitates which effectively pin grain and subgrain boundaries during static and continuous recrystallization. As a result, the alloy retains its fine grain size (about 7 micron), even after extensive superplastic deformation (>1000%). During deformation, dislocations Mg with a high Schmidt factor slip across subgrains but are trapped by subgrain boundaries, as a result of the strong pining of Al3Sc. This process leads to the conversion of low-angled subgrain boundaries to high-angled grain boundaries and the subsequent grain boundary sliding, which produces superelasticity. A model is proposed to describe grain boundary sliding accommodated by dislocation glide across grains with a uniform distribution of coherent precipitates. The model predictions is consistent with experimental observations.
Download or read book Metals Abstracts written by and published by . This book was released on 1995 with total page 1602 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Processing of 2090 Aluminum Alloy for Superplasticity by :
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).
Book Synopsis Superplasticity in a Thermo-Mechanically Processed Aluminum-10.2%Mg-0.52%Mn Alloy by : Max E. Mills
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.
Book Synopsis Deformation and Failure Mechanisms of a Modified Commercial Aluminum Alloy at Elevated Temperatures by : William Paul Green
Download or read book Deformation and Failure Mechanisms of a Modified Commercial Aluminum Alloy at Elevated Temperatures written by William Paul Green and published by . This book was released on 2004 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: Superplastic aluminum alloys have been the subject of recent research in the automotive industry for several reasons. First, the formability of such alloys under superplastic forming (SPF) conditions is quite good; second, the potential weight reduction associated with formed aluminum sheet as compared to traditional steel sheet is particularly important for automotive applications. Unfortunately, SPF-grade aluminum is relatively expensive, and the typical SPF process is expensive and time-consuming because of the high temperatures and slow strain rates involved. The present study investigates the potential for forming AA5083, the most common commercial alloy for SPF operations, at reduced temperatures and increased strain-rates. The deformation and failure mechanisms under these conditions are examined in a modified AA5083 material and are compared with data from unmodified AA5083. A new method of presenting creep transient data is presented and is used to determine deformation mechanisms at elevated temperatures. A modified AA5083 alloy produced by continuous casting (CC), and containing a small addition of Cu, was studied. This small addition of Cu causes the formation of Mg2Cu and MgCu2 intermetallic particles, which produce incipient melting. It is proposed that these low-melting-temperature phases may reside at grain boundaries and enhance grain-boundary sliding at low temperatures, which may explain the improved ductility of the Cu-containing alloy. Ductility variations for the Cu-containing alloy are also explored. The differences in tensile ductility between the Cu-containing AA5083 and unmodified AA5083 materials, produced by both CC and direct-chill (DC) casting, are related to differences in cavitation behavior. The final part of the present work is a study on the effect of various heat treatment schedules on the constituent particle distribution in AA5083. It is shown that a simple one-day aging treatment at a moderate temperature can effectively reduce the interparticle spacing. This may lead to a finer recrystallized grain size [1] and, thus, improve superplastic properties.
Book Synopsis Thermomechanical Processing of Al Alloy 2090 for Grain Refinement and Superplasticity by : Procopios T. Spiropoulos
Download or read book Thermomechanical Processing of Al Alloy 2090 for Grain Refinement and Superplasticity written by Procopios T. Spiropoulos and published by . This book was released on 1987 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: An aluminum copper lithium zirconium alloy, recently registered as 2090, with 7 percent lower density and 10 percent higher elastic modulus, has been introduced as a replacement for the 7075-T6 alloy. The purpose of this research is to investigate the applicability of thermomechanical processing methods developed at NPS for materials including Al-Mg and Al-Mg-Li alloys, to the 2090 alloy. The material is hot worked, cold worked, aged and warm rolled to a total true strain of about 2.4. Tensile tests were conducted at different temperatures and strain rates allowing a determination of the effect of the processing on microstructural evolution and the superplastic behavior of this material.
Book Synopsis Superplastic Forming and Diffusion Bonding of Rapidly Solidified, Dispersion Strengthened Aluminum Alloys for Elevated Temperature Structural Applications by :
Download or read book Superplastic Forming and Diffusion Bonding of Rapidly Solidified, Dispersion Strengthened Aluminum Alloys for Elevated Temperature Structural Applications written by and published by . This book was released on 1989 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Developing a High Strain Rate Superplastic Forming Capability in Aluminum Alloys by :
Download or read book Developing a High Strain Rate Superplastic Forming Capability in Aluminum Alloys written by and published by . This book was released on 2003 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: The applications for superplastic forming (SPF) are currently limited because the strain rates involved in the forming process tend to be relatively slow (typically 10(exp -3)-10 (exp -1) 1 s(exp -1). There would be a very significant increase in the applications for SPF if the forming rates were increased to 10(exp -1) 1 s(exp -1). It can be shown on theoretical grounds that SPF-may be achieved at faster rates by reducing the grain size of the superplastic material. Unfortunately, it is generally not possible to achieve grain sizes as small as the submicrometer level using conventional thermo-mechanical processing. This paper demonstrates the potential for achieving ultrafine grain sizes through the application of severe plastic deformation. It is shown that two aluminum- based alloys exhibit superplastic elongations at very rapid strain rates when the alloys are processed using the procedure of Equal-Channel Angular Pressing (ECAP) in which the samples are pressed through a die containing a channel bent into an L-shaped configuration. It is demonstrated also that samples processed by ECAP can be Superplastically formed at very rapid strain rates.
Book Synopsis Government Reports Annual Index by :
Download or read book Government Reports Annual Index written by and published by . This book was released on 1991 with total page 1654 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Superplasticity at High Strain Rates in Aluminum Alloys by :
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.
Book Synopsis Materials Processing Handbook by : Joanna R. Groza
Download or read book Materials Processing Handbook written by Joanna R. Groza and published by CRC Press. This book was released on 2007-03-28 with total page 840 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of materials science and engineering is rapidly evolving into a science of its own. While traditional literature in this area often concentrates primarily on property and structure, the Materials Processing Handbook provides a much needed examination from the materials processing perspective. This unique focus reflects the changing comple
Download or read book Alloys Index written by and published by . This book was released on 1990 with total page 1040 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :National Aeronautics and Space Adm Nasa Publisher :Independently Published ISBN 13 :9781731402776 Total Pages :160 pages Book Rating :4.4/5 (27 download)
Book Synopsis Superplastic Forming and Diffusion Bonding of Rapidly Solidified, Dispersion Strengthened Aluminum Alloys for Elevated Temperature Structural Applicat by : National Aeronautics and Space Adm Nasa
Download or read book Superplastic Forming and Diffusion Bonding of Rapidly Solidified, Dispersion Strengthened Aluminum Alloys for Elevated Temperature Structural Applicat written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-11-19 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rapidly solidified alloys, based upon the Al-Fe-V-Si system and designed for elevated temperature applications, were evaluated for superplasticity and diffusion bonding behavior. Alloys with 8, 16, 27, and 36 volume percent silicide dispersoids were produced; dispersoid condition was varied by rolling at 300, 400, and 500 C (572, 752, and 932 F). Superplastic behavior was evaluated at strain rates from 1 x 10(exp -6)/s to 8.5/s at elevated temperatures. The results indicate that there was a significant increase in elongation at higher strain rates and at temperatures above 600 C (1112 F). However, the exposure of the alloys to temperatures greater than 600 C (1112 F) resulted in the coarsening of the strengthening dispersoid and the degradation of mechanical properties. Diffusion bonding was possible using low gas pressure at temperatures greater than 600 C (1112 F) which also resulted in degraded properties. The bonding of Al-Fe-V-Si alloys to 7475 aluminum alloy was performed at 516 C (960 F) without significant degradation in microstructure. Bond strengths equal to 90 percent that of the base metal shear strength were achieved. The mechanical properties and microstructural characteristics of the alloys were investigated. Ting, E. Y. and Kennedy, J. R. ALUMINUM ALLOYS; DIFFUSION WELDING; DISPERSION STRENGTHENING; DISPERSIONS; FORMING TECHNIQUES; SOLIDIFICATION; SUPERPLASTIC FORMING; SUPERPLASTIC FORMING; SUPERPLASTICITY; DEGRADATION; ELONGATION; MECHANICAL PROPERTIES; MICROSTRUCTURE; SILICIDES; STRAIN RATE...
