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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 elevated temperature tensile properties of S-200E commercially pure beryllium

Description: Experiments were performed at 300-100 C in longitudinal and transverse orientations at quasi-static strain rate 5.5 {times} 10{sup {minus}4}s{sup {minus}1}. Results show that the stress-strain curve is smooth, without yield points or serrations. Yield stress and ultimate tensile stress decrease monotonically with temperature. Similar strengths were measured for both orientations. Failure elongation vs temperature is complex.
Date: March 1, 1995
Creator: Henshall, G.A.; Torres, S.G. & Hanafee, J.E.
Partner: UNT Libraries Government Documents Department

The effect of artificial aging on the tensile properties of alclad 24S-T and 24S-T aluminum alloy

Description: An experimental study was made to determine the effect of artificial aging on the tensile properties of alclad 24S-T and 24S-T aluminum-alloy sheet material. The results of the tests show that certain combinations of aging time and temperature cause a marked increase in the yield strength and a small increase in the ultimate strength; these increases are accompanied by a very large decrease in elongation. A curve is presented that shows the maximum yield strengths that can be obtained by aging this material at various combinations of time and temperature. The higher values of yield stress are obtained in material aged at relatively longer times and lower temperatures.
Date: August 1943
Creator: Kotanchik, Joseph N.; Woods, Walter & Zender, George W.
Partner: UNT Libraries Government Documents Department

Tensile properties of AZ31A-0 magnesium-alloy sheet under rapid-heating and constant-temperature conditions

Description: Specimens of AZ31A-0 magnesium alloy sheet were heated to rupture at nominal rates of 0.2 F to 100 F per second under constant tensile load conditions. The data are presented and compared with the results of conventional tensile stress-strain tests at elevated temperatures after 1.2-hour exposure. A temperature-rate parameter was used to construct master curves from which stresses and temperatures for yield and rupture can be predicted under rapid-heating conditions. A comparison of the elevated-temperature tensile properties of AZ31A-0 and HK31XA-H24 magnesium-alloy sheet under both constant-temperature and rapid-heating conditions is included.
Date: August 1956
Creator: Kurg, Ivo M.
Partner: UNT Libraries Government Documents Department

Tensile properties of Inconel X sheet under rapid-heating and constant-temperature conditions

Description: From Summary: "Results of rapid-heating tests of Inconel X sheet are presented for nominal temperature rates of 0.2 degrees F to 100 degrees F per second under constant tensile load conditions. Yield and rupture stresses obtained under rapid-heating conditions are compared with the results of conventional tensile stress-train tests at elevated temperatures. A marked increase in strength is observed with increased temperature rates."
Date: August 1957
Creator: Kurg, Ivo M.
Partner: UNT Libraries Government Documents Department

Tensile properties of 7075-T6 and 2024-T3 aluminum-alloy sheet heated at uniform temperature rates under constant load

Description: Results are presented of tests to determine the effect of heating at uniform temperature rates from 0.2 degrees to 100 degrees F per second on the tensile properties of 7075-T6 d(75s-T6) and 2024-T3 (24s-T3) aluminum-alloy sheet under constant-load conditions. Yield and rupture stresses, obtained under rapid-heating conditions, are compared with results of elevated-temperature stress-strain tests for 1/2-hour exposure. Master yield-and-rupture-stress curves based on linear temperature-rate parameter are presented. Yield and rupture stresses and temperatures may be predicted by means of master curves and the parameter.
Date: July 1955
Creator: Heimerl, George J. & Inge, John E.
Partner: UNT Libraries Government Documents Department

Effects of Interstitial Boron and Alloy Stoichiometry on Environmental Effects in FeAl

Description: Room-temperature tensile tests were conducted on B-doped (300 wppm) and B-free polycrystalline FeAl alloys containing 37, 40, 45, and 48 at. % aluminum in pure hydrogen gas at pressures in the range of 10 sup minus 8 to 10 sup 3 Pa. The ductilities of both B-free and B-doped FeAl decreased with increasing Al content. However, at a given Al level, the ductility of B-doped FeAl was higher than that of its B-free counterpart. Fracture mode was independent of environment and dependent mainly on stoichiometry. Ductility was found to be very sensitive to environment, particularly in the lower Al alloys. Alloys that exhibited >10% ductility in UHV showed a decrease in elongation to fracture with increasing hydrogen pressure. Tests conducted in dry hydrogen gas result in greater ductilities than those conducted in air, indicating that water vapor is more detrimental than H sub 2 to the ductility of FeAl alloys.
Date: April 22, 1998
Creator: Cohron, J.W.; George, E.P. & Zee, R.H.
Partner: UNT Libraries Government Documents Department

THE EFFECT OF OXIDATION ON THE COMPRESSION STRENGTH OF CS-GBF GRAPHITE

Description: Data on the effects of oxidation on the compressive strength of graphite are presented. Results indicate that a rapid decrease in compressive strength in unirradiated graphite during initial oxidation, with a more gradual decrease during further oxidation. Irradiated samples exhibited greater compressive strength than non-irradiated. (J.R.D.)
Date: April 11, 1956
Creator: Griggs, B.
Partner: UNT Libraries Government Documents Department

Tensile creep performance of a developmental in-situ reinforced silicon nitride

Description: The evaluation was done between 1300 and 1425 C in ambient air. Minimum creep rate was evaluated vs tensile stress and temperature, and measured tensile creep performances of two different specimen geometries (buttonhead and dogbone - machined from same billet) were compared. This Si nitride exhibited comparable or better creep resistance than other Si nitrides described in the literature. Measured creep response of the material and lifetime were observed to be geometry dependent; the smaller cross-sectioned dogbone samples exhibited faster creep rates and shorter lives, presumably due to faster oxidation-induced damage in this geometry. The tensile creep rates and lifetimes were found to be well represented by the Monkman- Grant relation between 1350 and 1425 C, with some evidence suggesting stratification of the data for the 1300 C tests and a change in dominant failure mode between 1300 and 1350 C. Lastly, values of the temperature-compensated stress exponent and activation energy for tensile creep were found to decrease by 80 and 75% in compression, respectively, illustrating anisotropic creep behavior in this Si nitride.
Date: February 1, 1997
Creator: Wereszczak, A.A.; Kirkland, T.P.; Lin, H.T.; Ferber, M.K.; Li, C.W. & Goldacker, J.A.
Partner: UNT Libraries Government Documents Department

Mechanical Response of Stitched T300 Mat/Urethane 420 IMR Composite Laminates: Property/Orientation Dependence and Damage Evolution

Description: This report presents experimental and analytical results of investigations on the mechanical response of stitched T300 mat/urethane 420 IMR composite laminates with three different lay-up configurations. Tensile tests and short-term creep and recovery tests were conducted on the laminate coupons at various orientations. The X-ray photographic technique was adopted to detect the internal damage due to external loading history. The tensile data of laminates with antisymmetric and symmetric lay-ups indicated that lay- up sequences of cross-ply laminates do not have much influence on their tensile properties. However, misalignments within the stitch-bonded plies disturb the symmetry of intended quasi-isotropic laminates and thereby cause the mechanical properties to exhibit a certain amount of angular dependence. Classic lamination theory was found to be able to provide a very good prediction of tensile properties for the stitched laminates within linear range. Creep and recovery response of laminate coupons is greatly dependent on loading angles and load levels. The internal damage of laminate coupons is also directly related to loading angles and load levels as well as loading history.
Date: March 1, 2000
Creator: Deng, S. & Weitsman, Y.J.
Partner: UNT Libraries Government Documents Department

Solid-state joining of ultrahigh carbon steels

Description: A joining study of these steels was initiated to determine the feasibility of using ultrahigh carbon steels in structural applications. The high carbon content (1.5 wt%) in these steels and the desire to maintain the superplastic microstructure limit the use of conventional arc-welding processes. We chose two solid-state joining processes: diffusion bonding and inertia friction welding. Preliminary results show that sound bonds can be obtained with tensile properties nearly equal to those of the base metal. Of three UHC steels bonded by both inertia-friction welding and diffusion- bonding processes, the one with the lowest aluminum content had the best overall properties. Diffusion bonding with a nickel interlayer showed the most promising results for the UHC steel containing 1.6 wt% aluminum. The properties of inertia-friction-welded steels can be improved by a post-weld heat treatment.
Date: April 22, 1993
Creator: Sunwoo, A.J.
Partner: UNT Libraries Government Documents Department

The strain-rate sensitivity of high-strength high-toughness steels.

Description: The present study examines the strain-rate sensitivity of four high strength, high-toughness alloys at strain rates ranging from 0.0002 s-1 to 200 s-1: Aermet 100, a modified 4340, modified HP9-4-20, and a recently developed Eglin AFB steel alloy, ES-1c. A refined dynamic servohydraulic method was used to perform tensile tests over this entire range. Each of these alloys exhibit only modest strain-rate sensitivity. Specifically, the strain-rate sensitivity exponent m, is found to be in the range of 0.004-0.007 depending on the alloy. This corresponds to a {approx}10% increase in the yield strength over the 7-orders of magnitude change in strain-rate. Interestingly, while three of the alloys showed a concominant {approx}3-10% drop in their ductility with increasing strain-rate, the ES1-c alloy actually exhibited a 25% increase in ductility with increasing strain-rate. Fractography suggests the possibility that at higher strain-rates ES-1c evolves towards a more ductile dimple fracture mode associated with microvoid coalescence.
Date: January 1, 2006
Creator: Dilmore, M.F. (AFRL/MNMW, Eglin AFB, FL); Crenshaw, Thomas B. & Boyce, Brad Lee
Partner: UNT Libraries Government Documents Department