Alcoa and ArcelorMittal
Profile story on Alcoa and ArcelorMittal for the American Energy and Manufacturing Competitiveness Summit.
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Alcoa wind turbines
An overview of Alcoa's wind energy program is given with emphasis on the the development of a low cost, reliable Darrieus Vertical Axis Wind Turbine System. The design layouts and drawings for fabrication are now complete, while fabrication and installation to utilize the design are expected to begin shortly.
Ai, D. K.↗
Liquid oxygen LOX compatibility evaluations of aluminum lithium (Al-Li) alloys: Investigation of the Alcoa 2090 and MMC weldalite 049 alloys
The behavior of liquid oxygen (LOX) compatibility of aluminum lithium (Al-Li) alloys is investigated. Alloy systems of Alcoa 2090, vintages 1 to 3, and of Martin Marietta Corporation (MMC) Weldalite 049 were evaluated for their behavior related to the LOX compatibility employing liquid oxygen impact test conditions under ambient pressures and up to 1000 psi. The developments of these aluminum lithium alloys are of critical and significant interest because of their lower densities and higher specific strengths and improved mechanical properties at cryogenic temperatures. Of the different LOX impact tests carried out at the Marshall Space Flight Center (MSFC), it is seen that in certain test conditions at higher pressures, not all Al-Li alloys are LOX compatible. In case of any reactivity, it appears that lithium makes the material more sensitive at grain boundaries due to microstructural inhomogeneities and associated precipitate free zones (PFZ). The objectives were to identify and rationalize the microstructural mechanisms that could be relaxed to LOX compatibility behavior of the alloy system in consideration. The LOX compatibility behavior of Al-Li 2090 and Weldalite 049 is analyzed in detail using microstructural characterization techniques with light optical metallography, scanning electron microscopy (SEM), electron microprobe analysis, and surface studies using secondary ion mass spectrometry (SIMS), electron spectroscopy in chemical analysis (ESCA) and Auger electron spectroscopy (AES). Differences in the behavior of these aluminum lithium alloys are assessed and related to their chemistry, heat treatment conditions, and microstructural effects.
Diwan, Ravinder M.↗
The Alcoa ram fastener: A reusable blind rivet
Results of tensile, shear, fatigue and accelerated weathering tests are presented for the ram fastener, a reusable, single unit blind rivet. The effects of variations in hole size, grip length and sheet thickness on strength properties of the fastener were determined. The test results show these fasteners to have strength characteristics suitable for light structural applications. Exposure to accelerated weathering did not impair their performance.
Dewalt, W. J.↗
Precision Aluminum Forming Final Report CRADA No. TC-0187-91
Lawrence Livermore National Laboratory (LLNL), Sandia National Laboratories (SNL), and ALCOA Technical Center joined together to advance the state of the art in computation analysis of aluminum forming processes. LLNL and SNL developed numerical modeling tools that incorporated material models and interface models provided by ALCOA. The two DOE laboratories and ALCOA jointly participated in the validation of the software package by modeling a set of benchmark forming data in the areas of rolling, forging, and extrusion. These forming benchmarks were produced by ALCOA. The software package was delivered to ALCOA and is being used in forming research.
36 MATERIALS SCIENCE↗
Specific Adaptation of Gas Atomization Processing for Al-Based Alloy Powder for Additive Manufacturing
The initial three atomization attempts resulted in “freeze-outs” within the pour tubes in the pilot-scale system and yielded no powder. Re-evaluation of the alloy liquidus temperatures and melting characteristics, in collaboration with Alcoa, showed further superheat to be necessary to allow the liquid metal to flow through the pour tube to the atomization nozzle. A subsequent smaller run on the experimental atomization system verified these parameters and was successful, as were all successive runs on the larger pilot scale system. One alloy composition froze-out part way through the atomization on both pilot scale runs. SEM images showed needle formation and phase segregations within the microstructure. Analysis of the pour tube freeze-out microstructures showed that large needles formed within the pour tube during the atomization experiment, which eventually blocked the melt stream. Alcoa verified the needle formation in this alloy using theoretical modeling of phase solidification. Sufficient powder of this composition was still generated to allow powder characterization and additive manufacturing trials at Alcoa.
36 MATERIALS SCIENCE↗
Analysis of Base Metal Microstructures and Mechanical Properties of a Single-Piece, Spin-Formed Forward Pressure Vessel Bulkhead
In 2012, a pathfinder forward pressure vessel bulkhead (FPVBH) for the Orion Multi-Purpose Crew Vehicle (MPCV) was fabricated using aluminum (Al) alloy 2219. The demonstration article was offered as a replacement for the baseline configuration, which at that time was a multi-piece welded construction using aluminum-lithium (Al-Li) alloy 2195. In 2014, the NASA Engineering and Safety Center (NESC) funded a Phase I effort to explore spin-forming as a manufacturing method to produce a complex-shaped, single-piece FPVBH for the crew module (CM) [1]. The primary focus of the NESC effort was to expand spin-forming technology to the fabrication of an Al-Li 2195 FPVBH. As a result, limited testing and analysis was performed on the original Al 2219 article. In this study, a sufficiently large plate of Al 2219 was not available for the fabrication of a FPVBH. Therefore, the forming blank comprised two plates (from different lots) butt welded together using a single friction stir weld. The welded forming blank was then spin formed into the FPVBH configuration and heat treated to the T62 temper. Mechanical property testing of the spin-formed 2219-T62 FPVBH revealed that the tensile properties were comparable to the Metallic Material Properties Development and Standardization (MMPDS) A-basis allowable for Al 2219-T6 wrought products. However, post-spin forming application of the standard heat treatment produced large, recrystallized grains in the material. The response varied within the two plates; one plate lot exhibited nearly complete recrystallization, while the other lot contained bands of recrystallization. Although no reduction in tensile properties was observed due to these microstructural variations, a more detailed investigation was recommended to better understand the effect of spin forming on the recrystallization mechanism and the impact on other material properties. The current study examined the microstructure and mechanical properties of the fully processed Al 2219-T62 FPVBH with emphasis on comparing differences between the two plates. Testing was limited to the cone region of the FPVBH. The two specific tasks in this study were: a) Characterization of the microstructure and mechanical properties in the two plates used in the FPVBH. b) Isolation of the impact of each step in the thermo-mechanical processing (TMP) sequence of the FPVBH on recrystallization and grain growth. Mechanical property testing sampled regions containing both large, recrystallized and small, unrecrystallized grains. Tensile strengths and elongations were equivalent in both regions and exceeded MMPDS A-basis allowables. Fracture toughness was equivalent in both regions and fracture morphology was typical of aluminum alloys. The fatigue precrack region of the fracture toughness specimens appeared more faceted in the recrystallized plate. This suggests that property testing that is more sensitive to grain size, such as fatigue crack growth rate and stress corrosion cracking, may be warranted. Alcoa reviewed the production records for the two plate lots and confirmed that composition of both plates was within the allowable range for Al 2219 and that plate processing steps were all performed within production limits. However, the Fe content was notably higher in the fully recrystallized plate, resulting in a greater volume fraction of large Fe-bearing inclusions and Al-Cu constituent particles. Alcoa did not provide details regarding plate processing variables for the two plate lots. It was surmised that deformation by hot rolling was the most accurate TMP simulation of commercial spin forming within a laboratory setting. Both hot rolling and spin forming comprise combinations of shear and compressive deformation. The through-thickness strain caused by hot rolling is symmetrical about the mid-plane, as the rollers contact both sides of the material. Shear strains are maximum at the inner and outer surfaces and trend toward zero at the mid-thickness. In contrast, spin forming utilizes a single roller on the outer surface, producing a gradient in shear stress through the thickness. Shear strains in spin-formed material are highest at the outer surface due to direct contact with the roller, and trend toward zero at the inner surface. Consequently, there will undoubtedly be some discrepancies in the mechanical response of hot-rolled and spin-formed products in the through-thickness direction. Interrupted TMP simulations were performed on remnant plate from the FPVBH forming blank in order to isolate the effects of a post-weld anneal, spin-forming deformation/thermal cycling, and solution heat treatment (SHT) on development of the recrystallized microstructures. Analysis confirmed that large, recrystallized grains formed exclusively during SHT and only after a certain deformation level was exceeded. Remnant plate from both lots that received thermal processing only did not exhibit recrystallization but exhibited fully recrystallized microstructures when processed by hot rolling. This indicates that (1) the level of deformation exceeded the critical level for recrystallization in both plates and (2) that the level of deformation during hot rolling was greater than that which accumulated during spin forming of the FPVBH. Comparison of the hot-rolled plate with the spin-formed material showed that the recrystallized grain size was larger in the FPVBH, providing further evidence that deformation levels were lower in the FPVBH. The most plausible explanation for the differing degrees of recrystallization in the two plates is particle stimulated nucleation (PSN) at the Fe-bearing inclusions and large Al-Cu constituent particles. In the plate with higher solute content, the greater volume fraction of these particles reduces the deformation level required to promote recrystallization. During spin forming the critical deformation level was likely exceeded for the higher Fe content plate resulting in a fully recrystallized microstructure. The lower Fe content plate developed a microstructure that exhibited bands of recrystallization due to the combination of a non-uniform distribution of particles and deformation. The critical deformation required for recrystallization was likely only exceeded during spin forming in regions of higher particle content. While there were differences in Fe content between these lots of Al 2219 plate, the composition of both was within defined alloy limits and Alcoa reported no anomalies during plate production. The observed differences in recrystallization after spin forming may reflect the inherent variability between these two lots of plate. The spin-forming vendor, Spincraft, reported that similar variations in recrystallized microstructures have been observed during examination of multiple spin-forming trials of a different 2xxx series aluminum alloy. Hence, tighter chemical specification limits on impurity levels in Al 2219 plate may help ensure uniform, predictable microstructures. Finally, the tensile and fracture toughness properties were not affected by the microstructural variations noted.
single-piece↗
Recovery Act. Tapoco project. Cheoah upgrade
Under Funding Opportunity Announcement Number: DE-FOA-0000120, Recovery Act: Hydroelectric Facility Modernization, Alcoa Power Generating Inc. (APGI), a fully owned subsidiary of Alcoa Inc., implemented major upgrades at its Cheoah hydroelectric facility near Robbinsville, North Carolina.
13 HYDRO ENERGY↗
Explore the Techno-Economic Viability of Using Large-Scale Additive Manufacturing (AM) For High-Performance Windows
Use of 3D printing, or additive manufacturing (AM) technology, in window design and construction is an under-explored area of research. Given the rapid advancements in AM technology and the potential for AM to address significant challenges associated with window design and manufacturing, there was a need to explore the feasibility of using AM technology. Alcoa’s Kawneer (Alcoa Building and Construction Systems) partnered with Oak Ridge National Laboratory’s (ORNL) Manufacturing Demonstration Facility (MDF) to explore the technical and commercial viability of large-scale 3D printing technologies with Kawneer’s AM window design. The project combined Alcoa/Kawneer’s design and expertise with ORNL’s equipment capability to create and study the world’s first 3D printed window using Big Area Additive Manufacturing (BAAM) technology. The results show that AM is useful for creating custom window shapes and sizes. With AM, more efficient windows can be made by sealing the glass pane into the printed frame during the printing process. In addition to energy savings, the use of AM reduces the manual labor required to produce custom windows.
36 MATERIALS SCIENCE↗
Deformation and fracture of thin sheet aluminum-lithium alloys: The effect of cryogenic temperatures
The objective is to characterize the fracture behavior and to define the fracture mechanisms for new Al-Li-Cu alloys, with emphasis on the role of indium additions and cryogenic temperatures. Three alloys were investigated in rolled product form: 2090 baseline and 2090 + indium produced by Reynolds Metals, and commercial AA 2090-T81 produced by Alcoa. The experimental 2090 + In alloy exhibited increases in hardness and ultimate strength, but no change in tensile yield strength, compared to the baseline 2090 composition in the unstretched T6 condition. The reason for this behavior is not understood. Based on hardness and preliminary Kahn Tear fracture experiments, a nominally peak-aged condition was employed for detailed fracture studies. Crack initiation and growth fracture toughness were examined as a function of stress state and microstructure using J(delta a) methods applied to precracked compact tension specimens in the LT orientation. To date, J(delta a) experiments have been limited to 23 C. Alcoa 2090-T81 exhibited the highest toughness regardless of stress state. Fracture was accompanied by extensive delamination associated with high angle grain boundaries normal to the fatigue precrack surface and progressed microscopically by a transgranular shear mechanism. In contrast the two peak-aged Reynolds alloys had lower toughness and fracture was intersubgranular without substantial delamination. The influences of cryogenic temperature, microstructure, boundary precipitate structure, and deformation mode in governing the competing fracture mechanisms will be determined in future experiments. Results contribute to the development of predictive micromechanical models for fracture modes in Al-Li alloys, and to fracture resistant materials.
Wagner, John A.↗
Stress Corrosion Testing
Advanced testing of structural materials was developed by Lewis Research Center and Langley Research Center working with the American Society for Testing and Materials (ASTM). Under contract, Aluminum Company of America (Alcoa) conducted a study for evaluating stress corrosion cracking, and recommended the "breaking load" method which determines fracture strengths as well as measuring environmental degradation. Alcoa and Langley plan to submit the procedure to ASTM as a new testing method.
Source record↗
Specific Adaptation of Gas Atomization Processing for Al-Based Alloy Powder for Additive Manufacturing
The charge for each gas atomization experiment was provided by Alcoa and consisted of cast blocks cut into 1 inch by 1 inch square rods of the chosen aluminum alloys. The atmosphere in the melting chamber and connected atomization system was evacuated with a mechanical pump prior to backfilling with ultrahigh purity (UHP grade) Ar. The melt was contained in a bottom tapped alumina crucible with an alumina stopper rod to seal the exit while heating to a pouring temperature of 1000 – 1400°C. When the desired superheat was reached, the stopper rod was lifted and melt flowed through pour tube and was atomized with Ar from a 45-22-052-409 gas atomization nozzle (or atomization die), having a jet apex angle of 45 degrees with 22 cylindrical gas jets (each with diameter of 1.32 mm or 0.052 inches) arrayed around the axis of a 10.4 mm central bore. The Ar atomization gas supply regulator pressure was set to produce nozzle manifold pressures for the series of runs at pressures of 250-650 psi. Secondary gas halos of Ar+O 2 and He also were added to the interior of the spray chamber at various downstream locations for additional cooling of the atomized droplets, surface passivation, and to prevent coalescence of the resulting powder.
36 MATERIALS SCIENCE↗
Laminated Metal Composites (LMC) for Aerospace Application Final Report CRADA No. TC-169-91
The project is a relationship between the Lawrence Livermore National Laboratory (LLNL), Aluminum Company of America (ALCOA), United Technologies, Pratt & Whitney, Rohr, Inc. and Sutek Coiporalion.
36 MATERIALS SCIENCE↗
Transition of Spent Nuclear Fuel to Dry Storage: Modeling activities concerning aluminum spent nuclear fuel cladding integrity
In 2017, a report was prepared by the Spent Nuclear Fuel Working Group in 2017 and titled “Technical Considerations and Challenges for Extended (>50 Years) Dry Storage” [1-2]. In this report several key scientific issues were identified pertaining to the problem of aluminum spent nuclear fuel (ASNF) and its safe removal from wet storage with subsequent drying and transfer to dry storage at the Department of Energy (DOE) Idaho National Laboratory (INL). This report outlines two modeling analyses performed for aluminum and aluminum oxides. The first analysis examined the solubility of aluminum oxides as a function of temperature and pH. This report presents existing literature produced as far back as the 1950’s and including significant analysis and reporting performed at Alcoa in the 1980’s. The primary technical gap was the lack of solubility data beyond that reported at standard temperature (25°C). The analysis examined these solubility curves as a function of temperature as well as phase type. The pH value of minimum solubility shifted with temperature but was insensitive to the oxide phase type. The solubility increases with temperature as would be expected, where an order of magnitude increase was observed from 25°C and 90°C. This data provides greater information to understand the various conditions experiences by ASNF including in dry storage in cases where water filming may occur. A second thermodynamic analysis was performed to examine the aluminum phase behavior as a function of temperature. This was performed to understand limitations and possible problems with fuel drying at elevated temperatures. Based on what has been established in previous reports, water remains chemically entrained within boehmite until temperatures exceeding 400°C. Analysis showed that significant phase changes occurred with highly alloyed AA6061 and AA5052 while the more pure aluminum (AA1100) showed nearly ideal behavior (i.e. limited phase changes). In the case of the more alloyed AA5052 and AA6061, the phase changes could take place at relatively low temperatures (100°C to 250°C), and thus may have already experienced some of these phase changes in service. As results are thermodynamic in nature, assessment of kinetics will be examined to determine if the phase changes are a concern for the relatively short fuel drying step.
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
Feasibility and process scale-up low cost alumina fibers for advanced Re-usable Surface Insulation (RSI)
The objective of this program was to establish feasibility of a process to produce low cost aluminum oxide fibers having sufficient strength, flexibility, and thermal stability for multiple re-use at temperatures to 1480 C in advanced RSI type heat shields for reentry vehicles. Using bench-scale processing apparatus, the Alcoa 'Saphiber' process was successfully modified to produce nominally 8 microns diameter polycrystalline alpha-alumina fiber. Thermal stability was demonstrated in vacuum reheating tests to 1371 C and in atmospheric reheating to 1483 C. Individual fiber properties of strength, modulus, and flexibility were not determined because of friability and short length of the fiber. Rigidized tile produced from fiber of nominally 8, 20 and 40 micron diameter had thermal conductivities significantly higher than those of RSI SiO2 or mullite at relatively low temperature but became comparable above about 1000 C. Tile densities were high due to short fiber length, especially in the coarser diameter fiber. No significant effect of fiber diameter on thermal properties could be determined form the data. Mechanical properties of tiles deteriorated as fiber diameter increased.
Pearson, A.↗
Extraction processes for the production of aluminum, titanium, iron, magnesium, and oxygen and nonterrestrial sources
The suitability of existing terrestrial extractive metallurgical processes for the production of Al, Ti, Fe, Mg, and O2 from nonterrestrial resources is examined from both thermodynamic and kinetic points of view. Carbochlorination of lunar anorthite concentrate in conjunction with Alcoa electrolysis process for Al; carbochlorination of lunar ilmenite concentrate followed by Ca reduction of TiO2; and subsequent reduction of Fe2O3 by H2 for Ti and Fe, respectively, are suggested. Silicothermic reduction of olivine concentrate was found to be attractive for the extraction of Mg becaue of the technological knowhow of the process. Aluminothermic reduction of olivine is the other possible alternative for the production of magnesium. The large quantities of carbon monoxide generated in the metal extraction processes can be used to recover carbon and oxygen by a combination of the following methods: (1) simple disproportionation of CO,(2) methanation of CO and electrolysis of H2O, and (3) solid-state electrolysis of gas mixtures containing CO, CO2, and H2O. The research needed for the adoption of earth-based extraction processes for lunar and asteroidal minerals is outlined.
D Bhogeswara Rao↗
Toward defining good writing: A rhetorical analysis of the words, sentences, and paragraphs in 16 industrial scripts
The assumption that teachers of technical writing agree on a definition of good writing was found to be without basis. Resolution of disagreements arising from close reading and textual analysis is described. Writing samples from corporate sources including IBM, ALCOA, Exxon, Weyerhaeuser, Bell Labs, Underwriters Laboratories, Dow Chemical, and US Steel were requested. A mixture of informative and persuasive examples, and examples directed at lay and specialist audiences were received. Analyses of 16 writing samples are reported. Analysis of word level, sentence level, and paragraph level, was completed. Syllabism, verb selection, nominalizations, vocabulary choices, t-units, subordination, sentence and clause length, syntactic order, patterns, development, topic sentences, propositional order, and transitions were analyzed.
Freisinger, R. R.↗
Utility experience with two demonstration wind turbine generators
Edison has committed 360 MW of nameplate generating capacity to wind energy by year 1990 in its long-range generation plan. To reach this goal the Company's wind energy program focuses on three areas: the continuous evaluation of the wind resource, the hands-on demonstration of wind turbine generators (WTG) and an association with wind park developers. Two demonstration WTGs have been installed and operated at Edison's Wind Energy Center near Palm Springs, California: a 3 MW horizontal axis Bendix/Schachle WTG and a 500 kW vertical axis Alcoa WTG. They are part of a one to two year test program during which the performance of the WTGs will be evaluated, their system operation and environmental impact will be assessed and the design criteria of future WTGs will be identified. Edison's experience with these two WTGs is summarized and the problems encountered with the operation of the two machines are discussed.
Wehrey, M. C.↗