Crack behavior and toughness of 2219-T81 aluminum alloy parent and weldments.
Al alloys sheet, plate and weldments crack behavior and fracture toughness at cryogenic temperatures, using notched and surface flawed plane strain specimens
Kropp, C. J.↗
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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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The values of the parameters of a distributed RC null network
Distributed RC notch filter normalized constants for dominant and nondominant transmission zero
Huelsman, L. P.↗
Propagation of Love waves in layers with irregular boundaries
Love wave propagation in layers with irregular boundaries, investigating scattered field to determine reflection from triangular notch
Wolf, B.↗
An accelerated stress corrosion test for high- strength ferrous alloys
High strength ferrous alloys susceptibility to stress corrosion in seacoast environment, tension loading single edge notched and fatigue cracked specimens in NaCl solution
Freedman, A. H.↗
Practical method of diffusion-welding steel plate in air
Method is ideal for critical service requirements where parent metal properties are equaled in notch toughness, stress rupture and other characteristics. Welding technique variations may be used on a variety of materials, such as carbon steels, alloy steels, stainless steels, ceramics, and reactive and refractory materials.
Holko, K. H.↗
Investigation of the fracture mechanics of boride composites Quarterly report no. 3
Tables on fracture mechanics of notched bars of boride composites and cobalt bonded tungsten carbide
Kaufman, L.↗
Design features and results from fatigue reliability research machines
Design and performance tests for reversed bending with steady torque fatigue test machine using notched steel specimens
Lalli, V. R.↗
Crack initiation at stress concentrations as influenced by prior local plasticity
Notched metal crack initiation, determining high cyclic loads effects by prior local plastic behavior at stress concentration
Crews, J. H., Jr.↗
Vise to hold bones or other irregular objects
Vise with stationary vee-shaped jaw and segmented notched jaw for holding irregular shaped objects is described. Operation of the device and specific application to holding bones are explained. Diagram of equipment is provided.
Dowell, R. H.↗
Crack toughness evaluation of hot pressed and forged beryllium
Beryllium fracture toughness test specimens were fatigue cracked using reversed cycling with a compression load two to three times the tension load. In worked beryllium, textures may be produced which result in fatigue cracks that are out of plane with the starter notch. Specimens of hot pressed stock exhibited load displacement records which were nonlinear throughout their course. Fracture specimens of both hot pressed and forged stock showed essentially no reduction of thickness and the fracture surfaces were flat and normal to the load axis. However, the stress intensity factor at maximum load increased with decreasing thickness. Load-displacement and electric potential records for the hot pressed beryllium specimens exhibited several anomalies such as negative residual crack mouth displacements and a decrease in electrical potential with increasing load.
Jones, M. H.↗
Development of an adhesively bonded beryllium propulsion structure for the Mariner Mars 1971 spacecraft
The design, testing, and fabrication of the support truss structure for the propulsion system of the Mariner 9 spacecraft are described. Support is provided by an 8.9-kg (19.5-lbm) truss assembly consisting of beryllium tubes adhesively bonded to magnesium end fittings. Beryllium was selected for the tubular struts in the truss because of its exceptionally high stiffness-to-weight ratio. Adhesive bonding, rather than riveting, was utilized to join the struts to the end fittings because of the low toughness (high notch sensitivity) of beryllium. Magnesium, used in the end fittings, resulted in a 50% weight saving over aluminum since geometric factors in the fitting design resulted in low stress areas where magnesium's lower density is a benefit.
Stevens, J. H.↗
Exploratory investigation of lift induced on a swept wing by a two-dimensional partial-span deflected jet at Mach numbers from 0.20 to 1.30
An exploratory investigation was conducted in the Langley 16-foot transonic tunnel at Mach numbers from 0.20 to 1.30 to determine the induced lift characteristics of a body and swept-wing configuration having a partial-span two-dimensional propulsive nozzle with exhaust exit in the notch of the swept-wing trailing edge. The Reynolds number per meter varied from 4,900,000 to 14,030,000. The effects on wing-body characteristics of deflecting the propulsive jet in the flap mode at nominal exhaust-nozzle deflection angles of 0 deg and 30 deg were studied for two nozzle designs with different geometry and wing spans.
Capone, F. J.↗
Ion and laser microprobes applied to the measurement of corrosion produced hydrogen on a microscopic scale.
Use of an ion microprobe and a laser microprobe to measure concentrations of corrosion-produced hydrogen on a microscopic scale. Hydrogen concentrations of several thousand ppm were measured by both analytical techniques below corroded and fracture surfaces of hot salt stress corroded titanium alloy specimens. This extremely high concentration compares with only about 100 ppm hydrogen determined by standard vacuum fusion chemical analyses of bulk samples. Both the ion and laser microprobes were used to measure hydrogen concentration profiles in stepped intervals to substantial depths below the original corroded and fracture surfaces. For the ion microprobe, the area of local analysis was 22 microns in diameter and for the laser microprobe, the area of local analysis was about 300 microns in diameter. The segregation of hydrogen below fracture surfaces supports a previously proposed theory that corrosion-produced hydrogen is responsible for hot salt stress corrosion embrittlement and cracking of titanium alloys. These advanced analytical techniques suggest great potential for many areas of stress corrosion and hydrogen embrittlement research, quality control, and field inspection of corrosion problems. For example, it appears possible that a contour map of hydrogen distribution at notch roots and crack tips could be quantitatively determined. Such information would be useful in substantiating current theories of stress corrosion and hydrogen embrittlement.
Gray, H. R.↗
Pendulum impact resistance of tungsten fiber/metal matrix composites.
The impact properties of copper, copper-10 nickel, and a superalloy matrix reinforced with tungsten fibers were studied. In most cases the following increased composite impact strength: increased fiber or matrix toughness, decreased fiber-matrix reaction, increased test temperature, hot working and heat treatment. Notch sensitivity was reduced by increasing fiber or matrix toughness. The effect of fiber content depended on the relative toughness of the fibers and matrix. Above 530 K a 60 volume per cent superalloy matrix composite had a greater impact strength than a turbine blade superalloy, whereas below 530 K a hot worked 56 volume per cent composite had a greater impact strength than the superalloy.
Winsa, E. A.↗
Calibration of combined bending-torsion fatigue reliability data reduction
The combined bending-torsion fatigue reliability research machines are described. Three such machines are presently in operation. The calibration of these machines is presented in depth. Fatigue data generated with these machines for SAE 4340 steel grooved specimens subjected to reversed bending and steady torque loading are given. The data reduction procedure is presented. Finally, some comments are made about notch sensitivity and stress concentration as applied to combined fatigue.
Kececioglu, D.↗
Irradiation effects on 17-7 PH stainless steel, A-201 carbon steel, and titanium-6-percent-aluminum-4-percent-vanadium alloy
Irradiation effects on three materials from the NASA Plum Brook Reactor Surveillance Program were determined. An increase of 105 K in the nil-ductility temperature for A-201 steel was observed at a fluence of approximately 3.1 x 10 to the 18th power neutrons/sq cm (neutron energy E sub n greater than 1.0 MeV). Only minor changes in the mechanical properties of 17-7 PH stainless steel were observed up to a fluence of 2 x 10 to the 21st power neutrons/sq cm (E sub n greater than 1.0 MeV). The titanium-6-percent-aluminum-4-percent-vanadium alloy maintained its notch toughness up to a fluence of 1 x 10 to the 21st power neutrons/sq cm (E sub n greater than 1.0 MeV).
Hasse, R. A.↗
Characterization of the mechanical and physical properties of TD-NiCr (Ni-20Cr-2ThO2) alloy sheet
Sheets of TD-NiCr processed using techniques developed to produce uniform material were tested to supply mechanical and physical property data. Two heats each of 0.025 and 0.051 cm thick sheet were tested. Mechanical properties evaluated included tensile, modulus of elasticity, Poisson's Ratio, compression, creep-rupture, creep strength, bearing strength, shear strength, sharp notch and fatigue strength. Test temperatures covered the range from ambient to 1589K. Physical properties were also studied as a function of temperature. The physical properties measured were thermal conductivity, linear thermal expansion, specific heat, total hemispherical emittance, thermal diffusivity, and electrical conductivity.
Fritz, L. J.↗
Factors affecting miniature Izod impact strength of tungsten-fiber-metal-matrix
The miniature Izod and Charpy impact strengths of copper, copper-nickel, and nickel-base superalloy uniaxially reinforced with continuous tungsten fibers were studied. In most cases, impact strength was increased by increasing fiber or matrix toughness, decreasing fibermatrix reaction, increasing test temperature, hot working, or heat treating. Notch sensitivity was reduced by increasing fiber content or matrix toughness. An equation relating impact strength to fiber and matrix properties and fiber content was developed. Program results imply that tungsten alloy-fiber/superalloy matrix composites can be made with adequate impact resistance for turbine blade or vane applications.
Winsa, E. A.↗