Download or read book Superplastic Forming an Aluminium lithium Alloy AA8090 written by Ana Sofia Climaco Monteiro D'Oliveira and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Aluminum Lithium Alloys written by S. Balasivanandha Prabu and published by Elsevier Inc. Chapters. This book was released on 2013-09-20 with total page 51 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the late 1950s, lithium is being used as an alloying element in aluminum. Their excellent ductility, which allows superplastic forming, along with their ability to decrease the density, makes aluminum-lithium alloys a primary choice for many structural applications in aerospace industry. This chapter initially discusses the processes and mechanisms that give rise to significant plasticity/Superplasticity in these alloy systems. The superplastic behavior of Al-Li alloys and their applications in forming are then discussed. The thickness variation during superplastic forming strongly depends on the peak strain rate sensitivity index (m) of the material, and an increase in the m value reduces the thickness variation in the formed component. The factors that help increase the value of m are enumerated. Superplastic forming is carried out at temperatures ≥ 0.5 Tm (Tm is the absolute melting temperature), often closer to 0.7 − 0.8 Tm. Significant cavitation and grain growth are present at such high temperatures. This has ushered in low temperature superplastic forming by the production of ultra-fine grain sizes via dispersion strengthening and severe plastic deformation (SPD). The promise of superplastic forming of Al-Li alloys for the future and the factors including cost that limit the use of Al-Li alloys are also discussed.

Download or read book Flow Behavior and Microstructural Evolution During Superplastic Deformation of AA8090 Aluminum lithium Alloy written by and published by . This book was released on 1906 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Superplasticity in AA8090 Al-Li alloy has been a subject of extensive studies, due to its potential for commercial applications since last decade. However, the anisotropy and microstructural gradient existing in this material introduce additional complication in understanding the mechanisms for superplastic deformation and has resulted in a debate about the role of dislocation activity. This has necessitated a more detailed microstructural study, especially texture, than that is commonly required to understand the deformation mechanism in other superplastic materials. Attempt has been made in this investigation to achieve this by means of microstructural characterization of specimens deformed in ten ion by using optical microscopy, TEM, SEM and orientation imaging microscopy (OIM). The microstructural characterization of the as-received material showed that there were three distinct layers in the cross-section of the sheet. Pancake grains in the center layer of about 1/3 thickness with brass-type texture, and nearly equiaxed grains on either side of it of about 1/3 thickness with copper texture. Tensile tests were conducted over a temperature range of $25{-}570\sp\circ$C and a strain rate range of $\rm 1 \times 10\sp{-4}{-}1 \times 10\sp{-2}/s.$ Optimum superplastic conditions were found in a temperature range of 500-530$\sp\circ$C and in a strain rate range of $\rm 1 \times 10\sp{-4}{-}1 \times 10\sp{-3}/s.$ These deformation conditions yielded the maximum value of strain rate sensitivity index $\rm(m \approx 0.5)$ and the minimum value of instability parameter (I). During superplastic deformation, there occurred grain growth, texture weakening and change in grain shape. The disappearance of initial microstructural gradient occurred at a strain of about 1.0. The relationship between grain size (d) and strain $(\varepsilon)$ could be expressed as $\rm d\propto\varepsilon\sp{q}, $ with the value of exponent q ranging from 0.21-0.44 depending on the test temperature. T.

Download or read book Flow Behavior and Microstructural Evolution During Superplastic Deformation of AA8090 Aluminum lithium Alloy written by Wenjie Fan and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Aluminum lithium Alloys written by Ramesh J. Kar and published by . This book was released on 1988 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Superplastic Forming of 8091 Aluminum Lithium written by C. E. Antone and published by . This book was released on 1988 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aluminum-Lithium alloys have been introduced to the Aerospace community as a way to decrease weight and improve stiffness over conventional aluminum alloys for structural components. A manufacturing method which as created a great deal of interest for A1-Li aerospace applications is the fabrication of net shape parts by superplastic forming (SPF). Aluminum-Lithium alloys present some unique handling problems and fabrication challenges for established practices in superplastic forming. This paper will discuss the manufacturing challenges and approaches of forming 8091 AL-Li by SPF and provide a brief overview into the material characteristic which make 8091 a successful candidate for SPF aircraft parts. Keywords: Superplastic forming (SPF); Aluminum lithium (AL-Li); Advanced aluminum; Aluminum alloys. (KT).

Download or read book Flow Behaviour and Microstructural Evolution During Superplastic Deformation of AA 8090 Aluminium lithium Alloy written by Wenjie Fan and published by . This book was released on 1998 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Aluminum Lithium Alloys written by N Eswara Prasad and published by Butterworth-Heinemann. This book was released on 2013-09-20 with total page 596 pages. Available in PDF, EPUB and Kindle. Book excerpt: Because lithium is the least dense elemental metal, materials scientists and engineers have been working for decades to develop a commercially viable aluminum-lithium (Al-Li) alloy that would be even lighter and stiffer than other aluminum alloys. The first two generations of Al-Li alloys tended to suffer from several problems, including poor ductility and fracture toughness; unreliable properties, fatigue and fracture resistance; and unreliable corrosion resistance. Now, new third generation Al-Li alloys with significantly reduced lithium content and other improvements are promising a revival for Al-Li applications in modern aircraft and aerospace vehicles. Over the last few years, these newer Al-Li alloys have attracted increasing global interest for widespread applications in the aerospace industry largely because of soaring fuel costs and the development of a new generation of civil and military aircraft. This contributed book, featuring many of the top researchers in the field, is the first up-to-date international reference for Al-Li material research, alloy development, structural design and aerospace systems engineering. - Provides a complete treatment of the new generation of low-density AL-Li alloys, including microstructure, mechanical behavoir, processing and applications - Covers the history of earlier generation AL-Li alloys, their basic problems, why they were never widely used, and why the new third generation Al-Li alloys could eventually replace not only traditional aluminum alloys but more expensive composite materials - Contains two full chapters devoted to applications in the aircraft and aerospace fields, where the lighter, stronger Al-Li alloys mean better performing, more fuel-efficient aircraft

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 Encyclopedia of Aluminum and Its Alloys Two Volume Set Print written by George E. Totten and published by CRC Press. This book was released on 2018-12-07 with total page 2957 pages. Available in PDF, EPUB and Kindle. Book excerpt: This encyclopedia, written by authoritative experts under the guidance of an international panel of key researchers from academia, national laboratories, and industry, is a comprehensive reference covering all major aspects of metallurgical science and engineering of aluminum and its alloys. Topics covered include extractive metallurgy, powder metallurgy (including processing), physical metallurgy, production engineering, corrosion engineering, thermal processing (processes such as metalworking and welding, heat treatment, rolling, casting, hot and cold forming), surface engineering and structure such as crystallography and metallography.

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 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 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 Aluminum lithium written by American Society for Metals and published by . This book was released on 1986 with total page 514 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Superplastic Forming written by Suphal P. Agrawal and published by . This book was released on 1985 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Superplastic Forming Adhesive Bonding of Aluminum Spf Ab Multi Sheet Structures written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-20 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: A significant fraction of airframe structure consists of stiffened panels that are costly and difficult to fabricate. This program explored a potentially lower-cost processing route for producing such panels. The alternative process sought to apply concurrent superplastic forming and adhesive bonding of aluminum alloy sheets. Processing conditions were chosen to balance adequate superplasticity of the alloy with thermal stability of the adhesive. As a first objective, an air-quenchable, superplastic aluminum-lithium alloy and a low-volatile content, low-viscosity adhesive with compatible forming/curing cycles were identified. A four-sheet forming pack was assembled which consisted of a welded two-sheet core separated from the face sheets by a layer of adhesive. Despite some preliminary success, of over 30 forming trials none was completely successful. The main problem was inadequate superplasticity in the heat-affected zones of the rib welds, which generally fractured prior to completion of the forming cycle. The welds are a necessary component in producing internal ribs by the 'four-sheet' process. Other challenges, such as surface preparation and adhesive bonding, were adequately solved. But without the larger issue of tearing at the weld locations, complex panel fabrication by SPF/AB does not appear viable. Wagner, John A. (Technical Monitor) and Will, Jeff D. and Cotton, James D. Langley Research Center NASA/CR-2003-212400, NAS 1.26:212400

Download or read book Diffusion bonding of an aluminium lithium alloy AA8090 written by A. Urena and published by . This book was released on 1989 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: