bluuebunny/crossref_metadata_2025_split huggingface dataset:
Strain-Cycling Fatigue Behavior of Ten Structural Metals Tested in Liquid Helium, Liquid Nitrogen, and Ambient Air
Authors: Nachtigall AJ 
Published: March 2009

The strain-cycling fatigue behavior of 10 different structural alloys and metals (two aluminum alloys, two titanium alloys, two stainless steels, a maraging steel, a high-nickel alloy, pure nickel, and pure copper) was investigated in liquid helium, liquid nitrogen, and ambient air at room temperature. Cylindrical hourglass-shaped specimens were loaded in compression and tension about zero mean strain to produce the desired strain ranges. Tensile properties were also obtained for each material and environmental temperature so that they could be used with the Manson-Hirschberg method of universal slopes to predict the fatigue behavior at each temperature.
At high cyclic fatigue lives, fatigue resistance increased with decreasing temperature for all the materials investigated. At low cyclic fatigue lives, fatigue resistance generally decreased with decreasing temperature for the materials investigated. Only for Inconel 718 did the fatigue resistance increase with decreasing temperature over the entire life range investigated. Comparison of experimental fatigue behavior with that predicted by the Manson-Hirschberg method of universal slopes showed that the strain-cycling fatigue behavior of these materials at cryogenic temperatures can be predicted with an accuracy comparable to that achieved in earlier investigations conducted at room temperature. Of the fatigue data obtained at cryogenic temperatures 80 percent were predicted within a life factor of 3.
Performance of Tied-Back Excavation at Water Tower Place
Authors: Gnaedinger JP , Gill SA , Keim PA 
Published: March 2009

The earth retention system used for the construction of a four-level underground garage at the Water Tower Place project, located in Chicago, Ill., is described. The excavation covered an area of 530 by 212 ft and extended to a depth of 44 ft below ground surface. It was supported by a cast-in-place reinforced concrete wall, 30 in. thick, 62 ft deep, installed by the slurry trench method. The wall spanned between the shafts of perimeter foundation caissons spaced 30 to 31 ft on centers, bearing on “hardpan” at a depth of 88 ft. The shafts were designed to carry part of the lateral load and were encased in a steel shell ⅝ in. thick to a depth of 72 ft. The slurry wall was supported at two levels: by a row of grouted earth anchors at the upper level 11 ft from the top, and by inclined rakers at the lower level 27 ft from the top.
Performance of the earth retention system was monitored by load cells on tiebacks, strain points on rakers, inclinometers, and by surface measurements. The load carried by each tieback at the completion of substructure was measured by a hydraulic jack. Measured loads are compared with those predicted by the commonly used earth pressure theories. Terzaghi and Peck's pressure diagram appears to fit the observed data. Lateral displacements were generally comparable to those recorded elsewhere for excavations supported by concrete walls and tiebacks. Vertical displacements contiguous to the cut were much less than the predictions based on settlement data reported by Peck for basement excavation in the downtown Chicago area.
Formability Testing and Deformation Analysis of Steel Sheet
Authors: Newby JR 
Published: March 2009

The success of production sheet metal stamping operations is determined by material properties, in conjunction with the forming process. The uniaxial tension test provides useful values to compare materials. These may relate to properties for improved biaxial stretchability and deep drawability as determined by simulative tests. Mathematical models derived from continuum mechanics and microplasticity theory may be used to explain simple deformation processes.
The failure of most production stampings results from local necking. For this reason, if the forming operation can be designed such that no thickness straining occurs, forming performance can be improved. An experiment demonstrating this was conducted.
Stress-Peen Straightening of Complex Machined Aircraft Parts
Authors: Skinner RD 
Published: March 2009

The forming and straightening of complex aircraft parts usually requires development to overcome springback, and often requires elevated temperature to minimize scrappage and reduce detrimental stresses. Also, it is more of an art than a controlled process. A new forming concept has been developed which employs shot peening of the part while it is restrained to a predetermined, elastic tensile stress. The process, called stress-peen forming, demonstrates excellent predictability by balancing the stress profile across the cross section, applying standard, strength-of-materials equations. The process provides ideal compressive stresses on all surfaces.
This paper presents the development of the process from its initial theory to preliminary straightening tests. The work includes the development of a mathematical model which (a) determines the initial stress in a complex forged part when it has been restored to its straightened position, and (b) predicts the amount of elastic prestress and permits the determination of the selected peening process parameters to produce the required balance stress equilibrium across the section. Limited compressive stress profiles due to shot peening and preliminary straightening test data are also presented.
Pilger Tooling Design for Texture Control
Authors: Schemel JH , McKenzie RW 
Published: March 2009

It has been shown earlier that the crystallographic texture of a Zircaloy tube is determined by the ratio of wall reduction to diameter reduction during tube fabrication. The use of this ratio as applied mathematically to the starting tube size and the final tube size does not take into account the complex nature of the tapers in the tube reducing tooling. Instantaneous values of the reduction ratio along the tube transition are shown to vary widely in tools of conventional design. A tooling design scheme that holds the reduction or strain ratio constant is developed by mathematical integration of the basic premise.
Data showing the results of various reductions made holding the reduction ratio constant are shown. These tests indicate that the texture rotation is not a linear function of the reduction ratio, and there is a strong indication that the strain field is not homogeneous in thick-walled tubes.
Use of Ion Bombardment to Study Irradiation Damage in Zirconium Alloys
Authors: Adamson RB , Bell WL , Lee D 
Published: March 2009

Zircaloy-2 having several different microstructures, textures, and compositions has been bombarded with either 5 MeV or 46.5 MeV nickel ions at 300 to 600°C to achieve doses ranging from 0.65 to 87.0 displacements per atom (dpa). Similar material was reactor-irradiated near 320°C to neutron fluences between 0.8 and 3.2dpa. Transmission electron microscopy methods were used to identify and compare the nature of the defect structure produced by the ions and neutrons.
For doses below 10 dpa (8 × 1021 neutrons (n)/cm2 (E&gt; 1 MeV)) and temperatures below 400°C, the predominant defects formed by nickel ion bombardment are black spots and loops on the order of 100 Å (10 nm) diameter. For these conditions the damage appears to be similar in most ways to that produced by neutron irradiation. An exception is that a diffraction contrast effect termed “corduroy” is consistently observed after neutron irradiation but generally not after ion bombardment. At temperatures above 400°C, the residual microstructure appears to depend on the rate of displacement damage. For doses above about 10 dpa and irradiation temperatures between 400 to 500°C, bombardment with 5 MeV nickel ions produces a striking alignment of defects on {0002} planes. At 600°C, no residual irradiation damage was observed. For all conditions where damage was present, some of the defects had Burgers vectors with a component parallel to the C-axis. Possible implications of the various observations are discussed.
In—Reactor Stress Relaxation of Zirconium Alloys
Authors: Causey AR 
Published: March 2009

In-reactor stress-relaxation tests were done on zirconium alloys with different compositions, grain sizes, heat-tratments, cold-work, and specimen stress directions at 568 ± 5 K in a fast neutron flux (E &gt; 1 MeV) of 2.0 × 1017 neutrons (n)/m2s, for up to 8200 h with initial stresses up to 300 MPa. The relaxation behavior can be represented by σ/σo = D exp (-Kt) where σ/σo is the ratio of the unrelaxed stress at time t to the initial stress, D is a constant which approximates the stress ratio after a rapid initial drop, and K is a relaxation rate constant.
The effects of the metallurgical variables on the in-reactor stress relaxation of zirconium alloys is small. Variations in composition and heat-treatments change the relaxation rate constant by factors of 2 to 4, while variations due to cold-work and working direction change the constant by factors of up to 2. Stress-relieving (or aging) following cold-work decreases the initial stress drop.
Irradiation Damage Recovery in Some Zirconium Alloys
Authors: Carpenter GJC , Watters JF 
Published: March 2009

The recovery of irradiation damage in a number of zirconium alloys has been studied by means of hardness measurements. The experiments were designed to examine the effect of different solutes (copper, aluminum, titanium, niobium, molybdenum) and metallurgical condition on the stability of irradiation-induced defect clusters.
Sheet specimens have been irradiated at 50°C to a fast neutron fluence of 5.5 × 1019 neutrons (n)/cm2 and the hardness changes studies during isochronal annealing. The specimens were heat treated prior to irradiation as follows: (a) well annealed, to approach the equilibrium structure and (b) β-quenched. Most of the annealed alloys recovered in one stage over a temperature range of about 100°C within the range 300 to 460°C.
The behavior of the β-quenched specimens was more complicated due to the simultaneous annealing of the martensitic substructure and solute precipitation. The presence of a high supersaturation of niobium or molybdenum resulted in large hardness increments as a result of irradiation. This is believed to result from precipitation of the solute on a fine scale or to the formation of solute/radiation damage complexes.
Transmission electron microscopy under kinematical conditions revealed the presence of “black spot” images, 30 to 70Å (3 to 7 nm) in diameter in a concentration of ∼5 × 1016/cm3 The smallest images could not be clearly distinguished owing to the presence of a thin oxide film on the surfaces of thin foil specimens. Some possible implications of these results to the problem of in-reactor creep are discussed.
Corrosion and Hydriding Performance of Zircaloy Tubing After Extended Exposure in the Shippingport Pressurized Water Reactor
Authors: Hillner E 
Published: March 2009

Three original blanket fuel bundles from the Zircaloy-2 clad pressurized water reactor (PWR) at the Shippingport Atomic Power Station were discharged after continuous exposure for the entire first core, consisting of one original seed and three seed refuelings, and for the first seed life of the second core. Detailed visual examinations of these components after ∼4100 calendar days of operation (41 000 EFPH) revealed only the anticipated uniform gray-tan (post-transition) corrosion products with no evidence of a gross Zircaloy corrosion acceleration; all corrosion films were found to be tightly adherent to the underlying cladding.
An extensive destructive evaluation of two fuel rods from each of the three fuel bundles produced greater oxide film thicknesses (7 to 12 μm or 0.28 to 0.47 mils) than the values predicted from the time-temperature history of the components (3 to 5 μm or 0.12 to 0.20 mils); an average corrosion acceleration factor of 2.4 can be calculated from the data. In slightly different terms, the observed corrosion acceleration was equivalent to raising the average surface temperature by ∼40°F. The accelerated corrosion attack was accompanied by a considerably lower total hydrogen pickup than that calculated from the observed film thicknesses. This combination Of an irradiation-induced corrosion acceleration and a less-than-predicted hydrogen absorption is suggestive of operation in an oxygenated environment although the Shippingport PWR coolant is maintained at a hydrogen concentration in the range 10 to 60 c3 H2/kg H2O.
Study of Zirconium Alloy Corrosion Parameters in the Advanced Test Reactor
Authors: Johnson AB , LeSurf JE , Proebstle RA 
Published: March 2009

The influence of nuclear radiation on zirconium alloy corrosion was studied in the North (1D) loop of the Advanced Test Reactor (ATR). The loop was new and therefore was free of fissionable contamination. The principal corrosion parameters were: alloy composition (Zircaloy-2, Zircaloy-4, Zr-2.5Nb, and crystal bar zirconium); flux level (unirradiated, 6 × 1012 to 1.7 × 1014 neutrons (n)/cm2 s &gt; 1 MeV); metallurgical condition (Zircaloy-4 and Zr-2.5Nb in two conditions); oxygen concentration (0.6 ppm O2 and &lt; 0.05 ppm O2); and surface pretreatment (as-etched, thin prefilms, and thick prefilms). Maximum exposures were 61.6d (oxygenated) and 102.1 d (deoxygenated) at 280°C, 2000 psig, in pH 10 LiOH.
In the oxygenated test, corrosion rates were substantially accelerated at high-flux locations. At the low-flux location, corrosion rates were unaffected or slightly accelerated on Zircaloy-2 and -4, substantially accelerated on zirconium, and slightly reduced on Zr-2.5Nb. Thick prefilms tended to suppress accelerated corrosion in the oxygenated system. In the deoxygenated test, corrosion rates were substantially accelerated for zirconium, but were only slightly above unirradiated values for the other materials.
The results from the ATR loop paralleled previous results from the ETR G-7 loop, indicating that dissolved oxygen, rather than fissionable contamination, was the principal cause of accelerated corrosion in both systems.
The Zr-2.5Nb alloy (quenched, cold-worked, aged) had the lowest weight gains and hydrogen absorption in both oxygenated and deoxygenated tests, but showed some pustule formation in the oxygenated test.
Zircaloy-2 coupons which had oxidized rapidly to 120 to 160 mg/dm2 (2.0 to 2.6 mg/dm2d) in the oxygenated system were transferred to the deoxygenated system. After transfer the corrosion rates decreased to 0.5 to 0.6 mg/dm2d. Inspection of coupons under polarized light revealed evidence of oxide porosity on coupons undergoing accelerated corrosion.
A New Technique for Determining the Deformation and Frictional Characteristics of In Situ Rock
Authors: Pratt HR , Black AD , Brown WS , Brace WF 
Published: March 2009

We describe a new technique for measuring the deformation and load bearing capability of large intact and jointed in situ rock specimens under applied uniaxial stress. The specimen configuration is an equilateral triangular prism of constant cross section with one end still connected to the rock mass. The free end of the specimen is loaded by a triangular flat-jack package. Displacements are monitored along and across joints; strains are measured on the surface of the specimen.
Forty-six tests have been performed at five sites on solid and jointed specimens over a range of effective diameters from 6 to 50 in.; on surfaces with orientation ranging from horizontal to nearly vertical; and on a wide variety of rock types including granites, sandstones, amphibolites, and chloritic schists. The technique has been used to measure the effect of specimen size on the strength of intact rock and frictional characteristics such as maximum and residual shear stress, normal and shear stiffness, and friction angle on natural joints with surface areas up to 750 square inches.
Laboratory Calibration and Field Performance of Inclinometers
Authors: Butler DK 
Published: March 2009

The state of the art in the use of inclinometers in engineering is reviewed briefly. Use of inclinometers in structures such as earth and rockfill dams, embankments, piles, behind retaining walls, etc., can be instrumental in detecting conditions leading to both short-term catastrophic failure and long-term progressive failure.
The types of inclinometer systems in general use are discussed. Field data acquisition procedures are described as well as necessary considerations in the interpretation of the data. Among the considerations are instrument drift, calibration, cross-sensitivity, and casing spiral. A laboratory device is described which is capable of checking the calibration of inclinometers, the effect of drift on instrument output, and the effect of cross sensitivity on measured angles. Results of the laboratory evaluation of two inclinometer systems are presented.
Site Engineering Indexing of Rock
Authors: Aufmuth RE 
Published: March 2009

An “Engineering Index” has been developed, (Aufmuth, 1972) for use at field sites, by means of which the pertinent characteristics of the intact and in situ rock mass may be presented in a brief, clear, and relevant manner. The Engineering Index consists of two parts; a lithologic and an engineering description. The latter is determined accurately from field index tests which have been directly correlated to laboratory investigational procedures.
The Engineering Index allows for the rapid and economical determination of the engineering properties of rock materials under field conditions and facilitates the acquisition of design data and experience translation from site to site.
Exfoliation Corrosion Testing of 7075 and 7178 Aluminum Alloys—Interim Report on Atmospheric Exposure Tests
Authors: Sprolws DO , Summerson TJ , Loftin FE 
Published: March 2009

Atmospheric exposures of 18 to 39 months have been completed at seacoast and inland industrial locations to determine the resistance to exfoliation corrosion of specially heat-treated test panels of high-strength aluminum alloys. Two seacoast locations, one at Point Judith, Rhode Island, and another at Daytona Beach, Florida, were selected, together with an industrial location near Chicago, Illinois, to represent the relatively severe atmospheric conditions to which aluminum alloy aircraft structures are subjected in service. The purpose of these tests was to demonstrate the relationship of the performances in the accelerated exfoliation corrosion tests previously evaluated by this task group with those in relatively aggressive natural environments.
The exfoliation performance is being evaluated on test panels heat treated to produce three different metallurgical structures that would be expected to provide a high, low, and medium resistance to exfoliation of both a 7075 alloy extrusion and a 7178 alloy rolled plate. Results obtained thus far are gratifying in that the atmospheric exposures are ranking the test materials in the same relative order as the new ASTM Standard Method of Test for Exfoliation Corrosion Susceptibility in 7XXX Series Copper Containing Aluminum Alloys (G 34-72, EXCO test). That is, the materials that showed either a high or a low resistance to exfoliation in the EXCO test also showed the same performance in the seacoast atmosphere, and that which showed an intermediate resistance in the EXCO test showed more spotty and a slower rate of exfoliation in the atmospheric exposures.
Exfoliation of the most susceptible items initiated more rapidly (within five months) at the seacoast, but the exfoliation tended to be more uniform at the industrial site. Other factors such as the climatic conditions at the seacoast, location, and exposure position of the test panels are considered.
Ten-Year Seawater Tests on Aluminum
Authors: Ailor WH 
Published: March 2009

Seven aluminum alloys and panels of high-purity aluminum were exposed for ten years in seawater at Wrightsville Beach, N. C. Replicate 4 by 12-in. panels of each material were exposed in half-tide immersion and full immersion. Removals in triplicate were made at the end of one-, two-, five-, and ten-year exposures.
Other than the 1199 aluminum (99.99 percent purity), seven aluminum-magnesium alloys (5000 series) were tested. Panels were degreased prior to exposure and were cleaned ultrasonically after exposure in a chromic-phosphoric acid solution. After depth of pitting was measured, tension specimens were cut from each panel, and the mechanical properties determined.
Panels were heavily fouled with barnacles and other marine growth for all exposure periods. The fouling had little apparent effect on the pitting depth of the aluminum in tidal immersion, but generated heavy etching on some alloys during the 5 to 10 year exposure interval.
Little change in tensile properties after ten years' exposure was noted for any of the test alloys. Tensile losses reported for several alloys after full immersion include: 5086-0 (3.7 percent), 5154-H38 (5.1 percent), and 5457-H34 (5.2 percent). The high-purity 1199 and alloys 5154-H38, 5456-0, and 5456-H321 showed losses of 16 to 27 percent in elongation while the change in elongation for the 5086-0 was a decrease of about 6 percent.
Confirming other work, we found the corrosion rates to be greater for the full seawater immersion than for the tidal immersion. The lowest ten-year corrosion rate in the half-tide location was 0.014 mpy (mils per year) and the 5456-0, and the highest rate for the aluminum-magnesium 5000 series was 0.051 mpy for the 5456-H321 alloy. In full-immersion tests, the lowest rate was 0.064. For comparison, the rates for the 1199 alloy were 0.036 mpy in tidal and 0.061 mpy in full immersion. Corrosion weight losses and depth of pitting had reduced rates of growth over the interval between five years and ten years. Maximum depth of pitting for an alloy was generally at least four times the magnitude of the average of the twenty deepest pits.
The deepest pit found for any alloy after ten years was 72.0 mils for 5456-H321 in half-tide immersion and 131.0 mils for the same alloy (0 temper) in full immersion. Least apparent pitting depths occurred on alloys 5154-H38, 5457-H34, 5086-0 and high-purity 1199 where heavy etching tended to hide pits on the ten-year full-immersion panels.
Corrosion Tests in the Gulf Floor
Authors: Di Gregorio JS , Fraser JP 
Published: March 2009

Because of the importance of good corrosion control to the safe operation of offshore pipelines, a test program was started in 1966 to study the behavior of pipeline materials in and near the ocean bottom in waters of pipeline depth (50 to 500 ft). This program has included the study of the corrosion of pipeline steels in and near the ocean bottom, the cathodic protection required to control this corrosion, and the performance of coating, paint, and anode systems in and near bottom sediments of the Gulf of Mexico.
Results to date have shown that the corrosion of separate, buried steel panels and the cathodic protection current densities required to control this corrosion are less than in the ocean immediately above the mudline. The corrosion rate of unprotected steel panels exposed to seawater above the mud is as high as 11 mpy (mils per year) depending on the time and location of exposure. Unprotected panels below the mudline, however, corrode at rates of 1 to 3 mpy. Pitting corrosion of these panels is also more intense in the water above the mud than buried in the mud. The current density required to reduce the corrosion rate of these panels to less than 1 mpy is in excess of 3.2 mA/ft2 above the mudline; below the mudline a current density of 0.6 to 2.5 mA/ft2 is required to reduce the cor- rosion rate to the same level. The current density required to control corrosion decreases with increasing depth of burial below the mudline. The corrosion rates of electrically connected pipe lengths partially buried in the mud are inde- pendent of position relative to the mudline. A large amount of calcareous deposit was formed on zinc metal when it was made electrically negative for 10.5 months in seawater.