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Effect of Aging Aircraft Structures on Magnesium Parts

Description: Note presenting an analysis of a procedure for artificially aging assemblies and subassemblies to improve the strength properties of the wrought aluminum alloys comprising their principal structure. Information is given on the magnesium alloys which may be present. The forms in which magnesium alloys may be encountered are casings, extrusions, forgings, and sheet.
Date: April 1945
Creator: Winston, A. W.
Partner: UNT Libraries Government Documents Department

Tensile Properties of HK31XA-H24 Magnesium-Alloy Sheet Under Rapid-Heating Conditions and Constant Elevated Temperatures

Description: "Specimens of HK31XA-H24 magnesium-alloy sheet from an experimental batch were heated to failure at nominal temperature rates from 0.2 F to 100 F per second under constant-load conditions. Rapid-heating yield and rupture stresses are presented and compared with the yield and ultimate stresses from elevated-temperature tensile stress-strain tests for 1/2-hour exposure. Linear temperature-rate parameters were used to correlate rapid-heating results by constructing master curves which can be used for predicting yield stresses and temperatures and for estimating rupture stresses and temperatures" (p. 1).
Date: August 1956
Creator: Gibbs, Thomas W.
Partner: UNT Libraries Government Documents Department

Column Strength of Extruded Magnesium Alloys AM-C58S and AM-C58S-T5

Description: "Tests have previously been made to determine the column strength of magnesium alloy AM-C58S-T5 extruded rod, but these few data were not considered a satisfactorily wide basis for establishing a general formula for the column strength of this alloy. It was therefore decided to make additional tests on a number of extruded sections of magnesium alloy AM-C58S-T5 with some tests on AM-C58S for comparison" (p. 1).
Date: December 1945
Creator: Leary, J. R. & Holt, Marshall
Partner: UNT Libraries Government Documents Department

The Corrosion of Magnesium and of the Magnesium Aluminum Alloys Containing Manganese

Description: "The extensive use of magnesium and its alloys in aircraft has been seriously handicapped by the uncertainties surrounding their resistance to corrosion. This problem has been given intense study by the American Magnesium Corporation and at the request of the Subcommittee on Materials for Aircraft of the National Advisory Committee for Aeronautics this report was prepared on the corrosion of magnesium" (p. 419).
Date: 1927
Creator: Boyer, J. A.
Partner: UNT Libraries Government Documents Department

Interfacial structures and energetics of the strengthening precipitate phase in creep-resistant Mg-Nd-based alloys

Description: This article discusses the study of two interfaces– {112}β1/{1100}Mg and {111}β1/{1120}Mg– that are commensurate with β1/hcp-Mg orientation relationship via first principles calculations.
Date: January 17, 2017
Creator: Choudhuri, Deep; Banerjee, Rajarshi & Srivilliputhur, Srinivasan
Partner: UNT College of Engineering

Bearing tests of magnesium-alloy sheet

Description: From Summary: "Bearing tests of AM-3S, AM-52S, and AM-C57S magnesium-alloy sheet in various thicknesses and tempers were made. Bearing yield and ultimate strengths were determined and compared for various edge distances and for various ratios of loading-pin diameter to sheet thickness. Tensile strengths were determined and ratios of average bearing yield and ultimate strength to tensile strength are given."
Date: June 1943
Creator: Sharp, W. H. & Moore, R. L.
Partner: UNT Libraries Government Documents Department

Bearing strength of some sand-cast magnesium alloys

Description: Report presenting testing to determine the bearing strength characteristics of some magnesium-alloy sand castings and the relation between those and more commonly determined tensile properties. The primary sand-cast magnesium alloys of interest for aircraft design are AM403, AM260, and AM265. Results of all of the tension, compression, and shear tests are provided in tables.
Date: February 1947
Creator: Moore, R. L.
Partner: UNT Libraries Government Documents Department

The Determination of Hydrogen in Magnesium, Lithium, and Magnesium Alloys

Description: The following report describes the process of the determination of hydrogen in magnesium, lithium, and magnesium alloys, including methods of analyzing magnesium-lithium alloys for hydrogen, and the tin-fusion method used for determining the hydrogen content of pure magnesium that can also be used to analyze pure lithium for hydrogen.
Date: November 13, 1951
Creator: Mallett, Manley William, 1909-; Gerds, A. F. & Griffith, C. B.
Partner: UNT Libraries Government Documents Department

Magnesium-Uranium Alloy System

Description: Analytical, x-ray, thermal, and metallographic data have been obtained in the study of the magnesium-uranium system, and a proposed phase diagram has been constructed.
Date: 1954
Creator: Tracy, George A.; Chiotti, P. & Wilhelm, Harley A.
Partner: UNT Libraries Government Documents Department

Column Strength of Magnesium Alloy AM-57S

Description: Tests were made to determine the column strength of extruded magnesium alloy AM-57S. Column specimens were tested with round ends and with flat ends. It was found that the compressive properties should be used in computations for column strengths rather than the tensile properties because the compressive yield strength was approximately one-half the tensile yield strength. A formula for the column strength of magnesium alloy AM-57S is given.
Date: July 1943
Creator: Holt, M.
Partner: UNT Libraries Government Documents Department

Tensile and Compressive Tests of Magnesium Alloy J-1 Sheet

Description: Note presenting tensile and compressive stress-strain curves, stress-deviation curves, and secant modulus-stress curves for longitudinal and transverse specimens of magnesium alloy J-1 sheets 0.032 and 0.102 inch thick. Significant differences were found between the tensile and compressive stress-strain curves and between the compressive stress-strain curves for the longitudinal and transverse questions.
Date: December 1943
Creator: Aitchison, C. S. & Miller, James A.
Partner: UNT Libraries Government Documents Department

Plate Compressive Strength of FS-1H Magnesium-Alloy Sheet and a Maximum-Strength Formula for Magnesium-Alloy and Aluminum-Alloy Formed Sections

Description: "The plate compressive strength of FS-1h magnesium-alloy sheet was determined from local-instability tests of formed Z-section columns. The critical compressive stress was found to correlate well with the compressive stress-strain curve for the material. The curves of average stress at maximum load plotted against calculated elastic critical strain resulted in a family of curves similar to previous results for aluminum-alloy sheet" (p. 1).
Date: October 1948
Creator: Gallaher, George L.
Partner: UNT Libraries Government Documents Department

Microstructure for Enhanced Plasticity and Toughness

Description: Magnesium is the lightest metal with a very high specific strength. However, its practical applicability is limited by its toughness and reliability. Mg, being HCP has low ductility. This makes the improvement of toughness a grand challenge in Mg alloys. Friction stir processing (FSP) is a thermomechanical technique used to effect microstructural modification. Here, FSP was utilized to affect the toughness of WE43 sheets through microstructural modification. Room temperature Kahn-type tests were conducted to measure the toughness of WE43 sheets. Microscopic techniques (SEM, TEM) was utilized to study the effect of various microstructural factors like grain size, texture, constituent particles, precipitates on crack initiation and propagation. Tensile properties were evaluated by mini-tensile tests. Crack growth in WE43 sheets was also affected by mechanics and digital image correlation (DIC) was utilized to study the plastic zone size. The underlying mechanisms affecting toughness of these sheets were understood which will help in formulating ways in improving it. WE43 nanocomposites were fabricated via FSP. Uniform distribution of reinforcements was obtained in the composites. Improved mechanical properties like that of enhanced strength, increased hardness and stiffness were obtained. But contrary to other metal matrix composites which show reduction in ductility with incorporation of ceramic reinforcements, the nanocomposites showed good strength-ductility combination. The composites were precisely characterized and mechanisms governing this property were studied. The nano-length of the reinforcements was observed to be the main criteria and the dislocation-particle interaction, the main reason behind the strength-ductility property.
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Date: August 2016
Creator: Das, Shamiparna
Partner: UNT Libraries

Effect of Open Circular Holes on Tensile Strength and Elongation of Sheet Specimens of a Magnesium Alloy

Description: Note presenting an investigation of the effect of open circular holes on the tensile strength and elongation of sheet specimens of magnesium alloy AM-C52S in both the annealed and hard-rolled condition. Tests were made to study the effect of variable ratio of hole diameter to total specimen width and the effect of spacing and arrangement of the holes.
Date: June 1952
Creator: Barker, R. S.
Partner: UNT Libraries Government Documents Department


Description: A survey of Mg including the cost and availability of various high- purity grades, safe handling considerations, methods of distillation and production physical and thermodynamic properties, and the binary and ternary alloys is presented. A bibliography is included with 157 references. (J.R.D.)
Date: March 1, 1958
Creator: Breederman, M.; Bennett, G.A.; Burris, L. Jr.; Dillon, I.G.; Winsch, I.O.; Nathans, M.W. et al.
Partner: UNT Libraries Government Documents Department

Interfacial segregation and deformation of superplastically deformed Al-Mg-Mn alloys

Description: Microstructural and microchemical studies have been carried out on superplastically deformed Al-Mg-Mn (AA5083-type) alloys. Grain boundary composition was measured using a Scanning Auger Microprobe (SAM) and an Analytical Transmission Electron Microscope (ATEM), while conventional TEM was used for microstructural evaluation. Non-equilibrium segregation of Si to grain boundaries following deformation was measured by both techniques. Significant interfacial Si enrichment was only detected in gage sections of tensile specimens after uniaxial strains from 50 to 200%. Grip regions which experience identical thermal histories, but without plastic deformation, did not reveal Si segregation. Selected samples also showed a slight depletion of Mg at grain boundaries after deformation. The only reproducible observation of equilibrium segregation was in Zr-modified alloys, where Sn was detected by SAM in both the deformed and undeformed sections of the sample. Microstructural analysis documented subgrain formation and subgrain-precipitate interactions during superplastic deformation. In addition, many grain boundaries and precipitate interfaces contained small (5 to 20 nm) voids. Compositional analysis of these nano-voids revealed that they were enriched in Mg with the adjacent boundary regions correspondingly depleted.
Date: March 1, 1995
Creator: Vetrano, J.S.; Lavender, C.A. & Bruemmer, S.M.
Partner: UNT Libraries Government Documents Department

Ceramic materials testing and modeling

Description: Certain refractory ceramics (notably oxides) have desirable properties suitable for the construction of ceramic waste containers for long term use in nuclear waste disposal applications. In particular, they are far less prone to environmental corrosion than metals under realistic repository conditions. The aqueous corrosion rates of oxides such as magnesium aluminate spinel (MgAl{sub 2}0{sub 4}) and alumina (Al{sub 2}0{sub 4}) fall in the range of a few millimeters per million years. Oxide ceramics are also not likely to be subject to microbiologically influenced corrosion, which apparently can attack most, if not all, of the available engineering metals. Ceramics have a reputation for poor mechanical performance and large, impermeable objects are not easily fabricated by most current fabrication methods. As a result, the most promising approach for incorporating ceramics in large waste packages appears to be to apply a high density ceramic coating to a supporting metallic structure. Ceramic coatings 2048 applied by a thermal spray technique can be made effectively seamless and provide a method for final closure of the waste package while maintaining low average temperatures for the entire assembly. The corrosion resistance of the ceramic should prevent or delay water penetration to the underlying metal, which will in turn provide most of the mechanical strength and toughness required by the application. In this way, the major concerns regarding the ceramic coating become ensuring it is impervious to moisture, its adherence and its resistance to mechanical stresses during handling or resulting from rock fall in the repository. Without water, electrochemical corrosion and microbiologically influenced corrosion processes are considered impossible, so a complete coating should protect the metal vessels for far longer than the current design requirements. Even an imperfect coating should extend the life of the package, delaying the onset and reducing the severity of corrosion by limiting the ...
Date: April 30, 1998
Creator: Wilfinger, K. R., LLNL
Partner: UNT Libraries Government Documents Department

Laser beam welding of AZ31B-H24 magnesium alloy.

Description: The laser beam weldability of AZ31B magnesium alloy was examined with high power CW CO{sub 2} and pulsed Nd:YAG lasers. The low viscosity and surface tension of the melt pool make magnesium more difficult to weld than steel. Welding parameters necessary to obtain good welds were determined for both CW CO{sub 2} and pulsed Nd:YAG lasers. The weldability of the magnesium alloy was significantly better with the Nd:YAG laser. The cause of this improvement was attributed to the higher absorption of the Nd:YAG beam. A lower threshold beam irradiance was required for welding, and a more stable weldpool was obtained.
Date: September 29, 1998
Creator: Leong, K. H.
Partner: UNT Libraries Government Documents Department

Enhanced tensile ductility in Al-Mg alloys by solid-solution interactions

Description: The development of methods for obtaining high tensile elongation in aluminum alloys is of great importance for the practical forming of near-net-shape parts. Current superplastic alloys are limited in use by high material costs. The utilization of solute-drag creep processes, the approach used in this study, to obtain enhanced tensile ductility in aluminum alloys has lead to tensile elongations of up to 325% in simple, binary Al-Mg alloys with coarse grain sizes. This method has the advantage of lowering processing costs in comparison with superplastic alloys because a fine grain size is not necessary. Whereas superplastic alloys typically have a strain-rate sensitivity of m = 0.5, the enhanced ductility Al-Mg alloys typically exhibit m = 0.3 where maximum ductility is observed. Although a strain-rate sensitivity of rn = 0.5 can lead to elongations of over 1000% (superplastic materials) a value of m = 0.3 is shown experimentally to be sufficient for obtaining elongations of 150% to a maximum observed of 325%. Enhanced ductility is also affected strongly by ternary alloying additions, such as Mn, for which a preliminary understanding is pursued.
Date: November 29, 1995
Creator: Taleff, E.M.; Henshall, G.A.; Lesuer, D.R.; Nieh, T.G. & Wadsworth, J.
Partner: UNT Libraries Government Documents Department

Failures to model the development of a cube texture during the high temperature compression of Al-Mg alloys

Description: A strong (100) fiber texture has been observed under some circumstances after the compression and tension of Al-Mg alloys. It is not due to static recrystallization after the text, but probably connected with some form of dynamic recrystallization. Possibilities that this unusual texture might rise from some unconventional deformation mechanisms were searched for but not found.
Date: December 31, 1993
Creator: Kocks, U. F.; Chen, Shuh Rong & Dawson, P. R.
Partner: UNT Libraries Government Documents Department

Influence of grain structure and solute composition on the work hardening behavior of aluminium at cryogenic temperatures

Description: An unrecrystallized structure is found to significantly improve the work hardening characteristics by lowering the work hardening rate during early stages of deformation. This is in contrast to a recrystallized structure, which requires a higher work hardening rate to accommodate the greater degree of multiple slip necessary to maintain strain compatibility between the more randomly oriented grains. The stronger texture associated with the unrecrystallized structure allows deformation to occur more efficiently. Addition of magnesium also improves work hardening by increasing overall level of the work hardening rate. The improved characteristics of the work hardening behavior result in a parallel increase in both the strength and ductility at cryogenic temperatures. These findings are positive since they suggest a method by which improvements in the work hardening behavior and subsequent mechanical properties may be obtained through practical modifications of the microstructure and composition.
Date: July 1, 1993
Creator: Chu, D. & Morris, J. W. Jr.
Partner: UNT Libraries Government Documents Department

Phase stability in the Cd-Mg system

Description: This paper reports on results of a theoretical study of solid-state phase equilibria and short-range order in Cd-Mg alloys. Results of first-principles linear muffin-tin orbital method total-energy calculations for seven hcp-based superstructures have been combined with cluster-variation-method calculations of thermodynamic properties in order to compute the Cd-Mg phase diagram. Effect on the calculated phase diagram of contributions to the alloy free energy arising from atomic vibrations and structural relaxations are assessed using available experimental information for ordered and disordered alloys in the Cd-Mg system.
Date: December 31, 1993
Creator: Asta, M.; McCormack, R. & de Fontaine, D.
Partner: UNT Libraries Government Documents Department

New extensions in the development of deformation processed metal-metal matrix composites

Description: Copper-Refractory metal composites have been under development for some time. The experience gained with these materials has been used as a starting point for investigations into other alloy systems. Deformation processing for the production of metal-metal matrix composites has been applied to titanium-yttrium, yttrium-niobium, copper-cobalt, aluminum-niobium and magnesium-refractory metal alloys. This process has been used to produce elevated strength material and also for the production of electrical capacitors.
Date: October 1, 1993
Creator: Ellis, T. W. & Gibson, E. D.
Partner: UNT Libraries Government Documents Department