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 Processing of 2090 Aluminum Alloy for Superplasticity written by Gary E. Groh and published by . This book was released on 1988 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt: Existing superplastic forming techniques for A1 alloys rely on deformation at temperatures of 500 C to achieve the desired ductilities. The A1 alloy 2090 (A1-Li-Cu-Zr) has been successfully fabricated by such techniques, but at temperatures where cavitation during formation may significantly reduce the mechanical properties of the final product. It has been previously shown that cavitation can be effectively suppressed by forming at lower temperatures. The purpose of this research is to investigate the applicability of thermomechanical processing methods (developed at NPS for A1-Mg-X alloys) to produce a refined microstructure capable of supporting superplasticity at lower temperatures in A1 2090. Aluminum alloys, Copper, Lithium, Thermomechanically processing, Superplasticity, Theses. (mjm).

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 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 69 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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.

Download or read book Superplastic Forming of Aluminum Lithium 2090 Alloy written by Rocky Wong and published by . This book was released on 1994 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effect of Thermal Processing Practices on the Properties of Superplastic Al Li Alloys written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-06 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effect of thermal processing on the mechanical properties of superplastically formed structural components fabricated from three aluminum-lithium alloys was evaluated. The starting materials consisted of 8090, 2090, and X2095 (Weldalite(TM) 049), in the form of commercial-grade superplastic sheet. The experimental test matrix was designed to assess the impact on mechanical properties of eliminating solution heat treatment and/or cold water quenching from post-forming thermal processing. The extensive hardness and tensile property data compiled are presented as a function of aging temperature, superplastic strain and temper/quench rate for each alloy. The tensile properties of the materials following superplastic forming in two T5-type tempers are compared with the baseline T6 temper. The implications for simplifying thermal processing without degradation in properties are discussed on the basis of the results. Hales, Stephen J. and Lippard, Henry E. Unspecified Center...

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:

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 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 Developing a Superplastic Forming Capability in a Commercial Aluminum Alloy Without Scandium Or Zirconium Additions written by and published by . This book was released on 2002 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tests were undertaken to determine the feasibility of producing a superplastic forming capability in a commercial Al-2024 alloy through processing by equal-channel angular pressing (ECAP), where this alloy was selected because it contains no scandium or zirconium additions that are generally beneficial in retaining an array of small grains. Processing by ECAP produced grain sizes in the range from 0.3 to 0.5 micronmeter and static annealing showed these ultrafine grains were reasonably stable at temperatures up to 700 K. Superplastic elongations were achieved after ECAP with a maximum elongation of 500% at 673 K when using a strain rate of 1.0 x l0(exp -2) s(exp-1) The strain rate sensitivity was measured as 0.3 suggesting that dislocation glide is the rate-controlling mechanism. These results demonstrate the potential for achieving high tensile ductilities in conventional commercial aluminum alloys through processing by ECAP.

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.

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.

Download or read book Effects of Alloy Chemistry on Superplastic Forming of Rapid Solidification Processed Aluminum Lithium Alloys written by RJ. Lederich and published by . This book was released on 1986 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: The superplastic forming characteristics of rapid-solidification-processed (RSP) Al-3Li-based alloys containing varying amounts of copper, magnesium, cobalt, and zirconium and processed by different thermomechanical sequences were investigated. Their final microstructures were strongly dependent on the processing treatment and alloy composition. All the zirconium-containing alloys were processed to have a fine subgrain microstructure. These alloys deform predominantly by dislocation glide and climb processes and by subgrain boundary motion, and they exhibit up to 400% elongation, which is sufficient for many commercial forming applications. Cavitation was suppressed, and the mechanical properties were not affected by forming. A thermomechanical processing sequence was established that develops a completely recrystallized fine grain microstructure in the Al-Li-Cu-Zr alloys. The alloys with this recrystallized microstructure have excellent formability.

Download or read book Effect of Thermal Processing Practices on the Properties of Superplastic Al Li Alloys written by Stephen J. Hales and published by . This book was released on 1993 with total page 72 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 Processing and properties of advanced aluminum alloys written by John A. Wert and published by . This book was released on 1989 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: This project has as its focus microstructure control for improving fracture resistance of advanced aluminum alloys. Our progress report is divided into two major parts: Part I which is concerned with the quench sensitivity of the Al-Li-Cu-Mg alloy 2090 and the effect of quench rate on fracture behavior, and Part II which is concerned with the recovery and recrystallization mechanisms that occur in an alloy having a high density of dispersoid particles. The grain size of aluminum alloys can affect both strength and deformation behavior and often controls the degree of superplasticity during elevated temperature deformation. (jes).