bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of Some Macronutrients and Micronutrients and Some Toxic Elements in Sewage Sludges from Domestic and Industrial Influents Prior to Land Disposal: I. Development of Methods
Authors: Katz SA , Jenniss SW
Published: December 2008

Procedures for the determination of some micronutrients and macronutrients and some toxic elements in sewage sludge are reviewed and evaluated. Digestion with nitric acid and hydrogen peroxide prior to measurement by atomic absorption spectroscopy was well suited to the determination of heavy metals in sewage sludge nd compatible with the existing requirements and recommendations of the North American and Western European regulatory agencies. Ignition was found to satisfactorily prepare sewage sludge for the determination of phosphorus by spectrophotometry of the molybdenum blue complex, and extraction with water shows promise for isolating nitrites and nitrates from sewage sludge before their spectrophotometric determinations. The criteria used in evaluating the procedures were speed, simplicity, sensitivity, and selectivity.
Soil Moisture Monitoring and Sampling Probe for Underground Storage Tanks and Surface Impoundments
Authors: Morrison R , Mioduszewski D
Published: December 2008

A review of available technologies for monitoring leaks from underground storage tanks and surface impoundments was performed to identify equipment that was most suited for this purpose. A single probe that combines the functions of a tensiometer and lysimeter was selected for additional research based upon this review. The unit detects changes in matric potential when functioning as a tensiometer and can also collect soil pore-water samples as a lysimeter. The probe developed from this effort was instrumented for both manual or remote monitoring, recording, and sampling. Instrumentation for automated maintenance allowed the unit to operate for extended periods of time without refilling the tensiometer mode of the probe with liquid.

Probe density depends upon soil texture and moisture content, geometry of the containment structure, and depth of installation. Calculations for determining the optimum probe placement based upon the diameter of the porous ceramic portion along with soil dispersion characteristics determine the primary variables for determining the optimum number of probes for a given containment structure. Probe sensitivity is controlled by the porous surface to vessel liquid volume, the radius of the porous section, and type of surface instrumentation.
Practices for Sampling Solid Wastes from Point Discharges and Impoundments
Authors: Holcombe L , Johnson D , Lorenzen D
Published: December 2008

Practices for sampling solid wastes from point discharges and impoundments are being developed for ASTM Committee D-34 on Waste Disposal and will provide guidance for obtaining representative samples of solid wastes from point discharges and surface impoundments. The sampling guidelines outline safety procedures, design considerations, sampling equipment, and sampling procedures. Proper design is a key component of any waste sampling program and is emphasized in these practices. The frequency of sampling or the spatial distribution of samples required to obtain a descriptive sample depends on the variability of the waste composition and the precision of waste analysis required. Given the waste variability and precision requirements, the number of samples necessary can be calculated using fundamental statistical concepts.
ASTM Standard Leach Test D 3986: A History
Authors: Jackson K
Published: December 2008

In 1977 ASTM Subcommittee D19.12 (currently ASTM Committee D-34 on Waste Disposal) was organized to develop standard test methods for the evaluation of hazardous waste. A standard leach test was the first test that needed to be identified. The development of this standard leach test involved a two phase testing program. The phase one testing program included 21 laboratories testing six waste streams for three parameters. The phase one program identified the areas in the proposed test method that were responsible for the very high variability found during the testing program. The second phase testing program was designed and carried out to address those areas of variability. The proposed test method was adopted as a standard in June 1980.
A New Look at Storage of Hazardous Materials and Wastes
Authors: Warner DJ , Frick JH , Lovejoy WC , Burns GF
Published: December 2008

In response to the need for improved information concerning hazardous materials/wastes in a storage environment, the Hazardous Materials Technical Center (HMTC) reviewed the definition of hazardous materials and applicable regulations and developed a storage classification scheme for packaged commodities. Seventy-seven final storage compatibility groups were developed from 12 major areas defined by regulation. To arrive at this scheme, HMTC combines Department of Defense (DOD) hazardous material storage/disposal methods, industry-based storage/disposal guidelines, and survey/analysis of regulations affecting the public and military sectors (for example, Department of Transportation, Occupational Safety and Health Administration. Environmental Protection Agency, Nuclear Regulatory Commission). Tables provide major definitions, a priority list of materials for multiple hazard, and major groupings of hazardous materials. Figures illustrate the development of the 77 final compatibility groups.
Nonlinear Rotatory Power of 90° Twisted Nematic Liquid Crystals
Authors: Wu S-T , Hess LD
Published: December 2008

The optical rotatory power of 90° twisted nematic liquid crystal cells was measured with a CW CO2 laser and found to be intensity dependent for intensities > kW/cm2. We found that the rotatory power can either decrease monotonically or increase first and then decrease as the laser intensity increases; this effect depends on the liquid crystal layer thickness. A threshold-like transition was observed and the threshold power was found to be linearly proportional to the inverse square of the liquid crystal layer thickness. These results provide evidence that optical field induced molecular reorientation and thermal effect are responsible for the observed nonlinear optical effect. Self-defocusing, self-phase modulation and laser-induced damage were also observed with the use of a HeNe laser probe beam.
Application of a Computer-Automated IR Sensitive Camera To the Determination of Pulsed Laser Surface Damage Thresholds
Authors: Filbert PC , Guttman JL , Navoda CL , Watson BA
Published: December 2008

An inexpensive, easily constructed infrared-sensitive camera system which as an active electronic readout is described in detail and examples of its utility in the determination of surface damage thresholds are presented. A small fraction of the pulsed 1.06 μm laser beam incident on the sample is split off and directed to a screen. The beam spatial profile of each shot is then imaged onto a 100 × 100 photodiode array whose output is digitized and stored by a PDP 11/23 computer-controlled data acquisition system. Further processing of the image data by a VAX 11/780 computer yields a high resolution fluence contour map of the laser beam incident on the sample. This map is especially useful when irradiating areas of several cm2 during material testing experiments. The map, showing the variation of beam fluence over its cross-section, can be superposed over the damaged sample providing an accurate value for the surface damage threshold for the material or coating. Examples will be presented and additional advantages of large area irradiation discussed.
A Low Loss, High Power Variable Laser Attenuator
Authors: Foltyn SR , Griggs JE , Jolin LJ , Roberts JH , Keaton D
Published: December 2008

The need for improved means of beam attenuation in uv optical damage experiments has led to the development of a new reflective attenuator using conventional multilayer dielectric optics. The device has low insertion loss even for unpolarized beams, high damage resistance, continuously variable attenuation, and a large clear aperture. Also discussed is a transmissive version of this device which uses standard reflectors or edge filters. Either version lends itself well to computer automation.
Laser Generated Ripple Patterns on Dielectrics and Intermediate Band Gap Semiconductors
Authors: Mansour N , Reali G , Aiello P , Soileau MJ
Published: December 2008

In this paper we report the results of studies of laser generated ripple patterns on intermediate band gap semiconductors (e.g., ZnS, ZnSe) and dielectrics of various indices of refraction by 10.6 μm laser pulses. The results confirm, only on a coarse scale, the scenario of the formation of coherent structures on the front or rear surface of damaged materials. In particular, for a variety of transparent dielectrics, we carefully determined the ripple spacing through microscopic observation and by diffraction pattern measurements. The ripple spacing and direction are consistent with prior observation by other workers. Similar measurements on front and rear surfaces of ZnS and ZnSe were also carried out revealing the presence of domains of regularly spaced ripple formations and fine structures superimposed parallel to the main pattern. Such fine structures are also present in the damaged dielectric samples, although they are perpendicular to ripple direction. Furthermore a “wrong” orientation, i.e., parallel to the incident field, of the induced gratings was observed. This points toward a less naive interpretation of laser induced ripples than has been described in the literature thus far.
Some Recent Observations on the Properties of UHV-Deposited ZrO2
Authors: Raj T , Weaver LD , Tuenge SR , Price JS , Jungling KC
Published: December 2008

Single-layer ZrO2 coatings were deposited in an ultrahigh vacuum system by two techniques: laser evaporation (utilizing a 100-W, continuous wave, CO2 laser) and electron-beam evaporation. Substrate temperatures were maintained at either 150°C or 250°C with backfill oxygen pressures between 0 and 5×10−5 torr. The coatings were analyzed by Auger Electron Spectroscopy to determine stoichiometry and to provide information on the nature and level of impurities. The refractive indices for the coatings were determined by ellipsometry at 6328 Å. Selected coatings were damage tested at 531 nm.

This report discusses the influence of backfill pressure, substrate temperature and evaporation technique on thin film properties and compares the results obtained by Auger and ellipsometric analyses. Also presented is a comparison between films prepared under high vacuum and ultrahigh vacuum conditions.
Pulse Duration Dependence of 1064-nm Laser Damage Thresholds of Porous Silica Antireflection Coatings on Fused Silica Substrates
Authors: Milam D , Thomas IM , Weinzapfel C , Wilder JG
Published: December 2008

We used 1064-nm pulses with durations of 1, 5, 9 ns to measure laser-damage thresholds of 10 porous silica antireflection coatings deposited from both methanol and ethanol solutions containing silica particles with diameters of 10–20 nm. The median thresholds measured at the three pulse durations, 10.8 J/cm2, 26.5 J/cm2, and 38 J/cm2, scaled as pulse duration to the 0.56 power.
Variation of Transmittance Spectra of Porous Antireflection Coatings with Index Profile
Authors: Milam D , Peterson GG
Published: December 2008

Transmittance spectra were calculated for single-layer coatings with (1) homogeneous refractive index, (2) index profiles that increase monotonically with distance into the coating, and (3) index profiles that rise in discrete steps. The calculations predict that large transmittance at tuned wavelengths can be obtained using any of these coating designs and known, porous silica coating materials. The spectral bandwidth of transmittance maxima increases when the index profile is altered from homogeneous to any profile whose index increases montonically with thickness in the coating. Bandwidth is greatest for the linear-ramp coating whose index rises linearly from that of air to that of the substrate, but this design cannot currently be used because we are unable to fabricate silica coating material with the extremely large porosity needed to provide a coating index near unity at the air interface. For currently attainable fractional silica contents, estimated to be in the range 0.4–0.5, the optimum bandwidth is provided by a coating with a single discrete step in its index profile.
Effect of Overcoats on 355-nm Reflectors
Authors: Carniglia CK , Hart TT , Staggs MC
Published: December 2008

Previous experiments have demonstrated that halfwave overcoats of a low-index coating material are effective in increasing the damage thresholds of dielectric high reflector coatings (HR's) at the wavelengths of 1064 nm and 248 nm. This overcoat layer led to a 50% increase in damage threshold at 1064 nm and to a 100% increase in threshold at 248 nm. This paper presents new results on the effect of halfwave overcoats at an intermediate wavelength: 355 nm.

Results reported at last year's Boulder Damage Symposium indicated that halfwave silica overcoats were detrimental to the damage thresholds of HR's at 355 nm. New results confirm that silica overcoats decrease thresholds and also show that magnesium fluoride overcoats do not improve the thresholds at 355 nm. A series of eight reflectors without overcoats had an average threshold of 2.4 J/sq. cm. The addition of silica overcoats decreased the average threshold by 2%, while magnesium fluoride overcoats decreased the threshold by an average of 7%.
Interface and Bulk Absorption of Oxide Layers and Correlation to Damage Threshold at 1.06 μm
Authors: Ristau D , Dang XC , Ebert J
Published: December 2008

We describe an infrared line scanning technique for measuring the temporal and spatial development of a temperature field which is generated by a high power cw Nd-laser on the surface of a coated sample. A theoretical model based on the solution of the differential equation of heat transport for an instantaneous point source is discussed. In this theory the optical and thermal properties of a laser heated single layer are related to its temperature field. Investigations on a temperature calibration technique are made in order to rule out the effect of different emissivities of the coating materials under test. In the present study interface and bulk absorption of single layers and multilayer stacks are measured and related to the laser damage threshold attained from 15 ns pulses at 1.064 μm. The layers are produced by e-beam evaporation and by ion-beam assisted deposition. Results will be given on TiO2, Ta2O5, HfO2, Al2O3 and SiO2.
The Design of Optimum High Reflectivity Coatings for Grazing Angles of Incidence
Authors: Shellan JB
Published: December 2008

Although quarter-wave multilayer dielectric coatings (QW MLDCs) usually offer the highest reflectivity possible at a single wavelength, this may not be the case at grazing angles of incidence. For incident angles greater than the Brewster angle, the p polarization absorption can easily be several orders of magnitude higher than the s polarization absorption due to the destructive interference between the reflection from the superstrate — top layer interface and the rest of the coating. An analytic approach is developed for designing optimum reflectivity coatings at grazing angles of incidence, once the fraction of s and p polarized light is given. These coatings can give at least an order of magnitude reduction over QW MLDCs in total coating absorption, even for the case where less than 0.1% of the incident radiation is p polarized. The absorption of the designs found from the analytic results compare favorably with designs generated using numerical methods of non-linear optimization.
Self-Focusing in Damage Experiments Revisited
Authors: Soileau MJ , Williams WE , Van Stryland EW
Published: December 2008

Last year we reported that the power of importance in self-focusing experiments is the second critical power, P2, defined by P2=3.77 P1 rather than the often quoted P1=c λ2/(32π2n2). Here n2 is the nonlinear refractive index, c the speed of light and λ the wavelength (both in vacuum). The factor of 3.77 is a numerical factor coming from computer calculations as discussed by Marburger [1]. We also presented a method by which we could obtain n2 at irradiances very near to damage. In addition, we showed the experimental conditions under which self-focusing is unimportant in damage experiments. We have now extended these results so that in damage experiments where self-focusing is important we can estimate the reduced spot size within the bulk at damage and, thus, obtain the damaging electric field magnitude. This we do by observing the far field time integrated spatial irradiance distribution. We present data for SiO2, NaCl, BK-7, and CS2.
Two-Photon Absorption, Nonlinear Refraction and Optical Limiting in Semiconductors
Authors: Van Stryland EW , Vanherzeele H , Woodall MA , Soileau MJ , Smirl AL , Guha S , Boggess TF
Published: December 2008

Two-photon absorption coefficients β2 of eight different semiconductors with bandgap energy Eg varying between 1.4 and 3.7 eV are measured using 1.06 μm and 0.53 μm picosecond pulses. β2 is found to scale as E−3g as predicted by theory for the samples measured. Extension of the empirical relationship between β2 and Eg to InSb with Eg = 0.2 eV also provides agreement between previously measured values and the predicted β2. In addition the absolute values of β2 are in excellent agreement (the average difference being >26%) with recent theory which includes the effects of nonparabolic bands. The nonlinear refraction induced in these materials is monitored and found to agree well with the assumption that the self-refraction originates from the two-photon generated free carriers. The observed self-defocusing yields an effective nonlinear index as much as two orders of magnitude larger than CS2 for comparable irradiances. This self-defocusing in conjunction with two-photon absorption is used to construct a simple, effective optical limiter that has high transmission at low input irradiance and low transmission at high input irradiance. The device is the optical analog of a Zener diode.
Advanced Fastener Technology for Composite and Metallic Joints
Authors: Speakman ER
Published: December 2008

The investigations described in this paper were conducted to develop new fasteners and joining methods to reduce the weight and improve the fatigue life of aircraft structures. Three major modes of structural failure—fatigue, fretting, and stress corrosion—are discussed along with recommendations for improvement. Stresscoining was developed to cold-work aircraft structures for fatigue improvement. Fretting fatigue failures have been reduced by using Teflon coatings on fasteners and in faying surfaces of splice joints. Standard stress corrosion test blocks have been designed for evaluation of this failure mode. A crown flush rivet configuration has been developed that does not require head shaving after installation. Qualification tests were performed in compliance with MIL-STD-1312 to obtain Federal Aviation Administration and military approval.

Various new fasteners have been developed for aluminum, carbon-fiber composite, and titanium structures. These fasteners were designed to be “forgiving to the hole” in that they fill and prestress the hole uniformly without being extremely sensitive to hole-preparation tolerances. New low-cost specimens have been designed to provide a basis for screening and comparing fastener tests conducted by fastener manufacturers and aircraft companies. These programs are directed toward creating technology for achieving a more balanced fatigue-resistant aircraft structure.
Fatigue Life Enhancement and High Interference Bushing Installation Using the ForceMate Bushing Installation Technique
Authors: Champoux RL , Landy MA
Published: December 2008

The patented ForceMate bushing installation process, originally developed by McDonnell Aircraft, involves expansion of a hole and simultaneous installation of an interference fitted bushing. The process provides a significant improvement in the fatigue life of bushed holes in metallic structures and offers reduced bushing installation costs. Fatigue life improvement is attributed both to the creation of residual compressive stresses in the metal surrounding the hole and to the reduction in applied cyclic stress range caused by the interference fitted bushing. Installation is accomplished without loss of corrosion protection because of the initial clearance fit of the bushing in the hole. Installation costs are reduced by the elimination of liquid nitrogen needed for shrinkage of bushings, as well as the significant reduction in installation time and manpower.

This paper describes the ForceMate process in detail. Fatigue lives of simulated aluminum lug geometries with bushings installed using the ForceMate process were compared with lives of lugs with bushings installed using conventional shrink fit methods. Constant amplitude and flight-by-flight spectrum loading were used for cyclic testing. Life improvement factors of greater than 3:1 were shown. Bushing-to-hole interferences were significantly greater than those achievable with traditional shrink-fit installation techniques. The process was demonstrated effectively with bushings manufactured from beryllium-copper, aluminum-nickel-bronze, and steel alloys.
Evaluation of a Stochastic Initial Fatigue Quality Model for Fastener Holes
Authors: Yang JN , Manning SD , Rudd JL
Published: December 2008

An initial fatigue quality (IFQ) model, based on stochastic crack growth and the equivalent initial flaw size (EIFS) concept, is described and evaluated for the durability analysis of relatively small cracks in fastener holes [for example, <2.54 mm (0.10 in.)]. The IFQ model uses a stochastic crack growth rate model which accounts for crack growth rate dispersion. Procedures and concepts are also described and evaluated for optimizing initial flaw size distribution parameters based on pooled EIFS results. Fatigue crack growth test results for 7475-T7351 aluminum specimens subjected to fighter and bomber load spectra are used to evaluate the proposed IFQ model and model calibration procedures. The cumulative distribution of crack size at any given time and the cumulative distribution of the time-to-crack initiation (TTCI) at any given crack size are predicted using the derived EIFS distribution and a stochastic crack growth approach. The predictions compare well with the actual test results in the small-crack-size region. The methods described are very promising for durability analysis applications.
Experimental Characterization of Cracks at Open Holes and in Rounded-End Straight Attachment Lugs
Authors: Nicoletto G
Published: December 2008

The paper focuses on the application of the frozen-stress photoelastic technique to an assessment of various engineering solutions from the literature for several hole-related crack problems. Single corner, transitioning, and through-the-thickness cracks are examined. Remote tensile loading of a plate containing an open hole and 100% load transfer through a rigid pin in a rounded-end lug is considered.

Experimental evidence demonstrates the presence of stress intensity factor (SIF) gradients for every crack configuration. Good correlation with existing SIF solutions is found for the through-the-thickness configuration in lugs. Less conclusive are the comparisons with engineering estimates for corner cracks emerging from open holes and lug. The transitioning behavior of a part-through crack is also discussed. Finally, modeling aspects of three-dimensional fracture problems are examined.
Fatigue of Riveted Metallic Joints
Authors: Ekvall JC
Published: December 2008

Spectrum fatigue test results are presented on riveted lap joint and flush joint specimens made from 7075-T6 plate and extrusion and from 7091-T7E69 and IN9021 powder metallurgy (PM) aluminum alloys. For the lap joint specimens, the 7091-T7E69 PM plate material exhibited a shorter fatigue life than the 7075-T6 plate, 7091-T7E69 extrusion, and IN9021 extrusion materials. Crack growth rates were determined for the PM aluminum alloys from characteristic markings made on the fracture surfaces by the modified Minitwist fatigue loading spectrum. Fatigue life predictions were made for two types of 7075-T6 aluminum joints using the local stress-strain method of fatigue analysis. Finite element stress analyses were conducted to determine the local stress and strain at the fatigue critical location of the test specimens due to the spectrum of applied loads. Fatigue life predictions agreed with the test results within a factor of 1.22 for the two types of 7075-T6 specimens analyzed when accounting for the difference in fatigue properties of the materials with respect to grain direction.
Maintaining Scale and Sludge in Suspension in Automotive Cooling Systems
Authors: Starkey J , Engelhardt PR
Published: December 2008

The automotive cooling system will have hardness present as a result of the water supplies used. This hardness along with the inhibitors in the antifreeze can lead to scale deposits forming, especially in high heat transfer areas. Corrosion products can also form and contribute to sludges in the coolant system. These deposits and sludges can reduce heat transfer, block radiators causing higher operating temperatures, and plug heater cores. Experimental tests were conducted to determine the effectiveness of different commercial antifreezes as scale and sludge inhibitors in a laboratory test boiler. The addition of an environmentally safe organic additive to a commercial antifreeze gives better scale inhibition on a high heat transfer surface than the same antifreeze without the additive. The amount of scale was determined and was analyzed.
Additive Package for Used Antifreeze
Authors: Conley JH , Jamison RG
Published: December 2008

The objective of this study was to develop an additive package that would allow the continued use of MIL-A-46153 antifreeze after its inhibitor system reached a marginal condition. Since Military Specification for Antifreeze, Ethylene Glycol, Inhibited, Heavy-Duty, Single-Package (MIL-A-46153) is a composition specification with a well documented history, a field test kit is used to determine when the antifreeze should be replaced. Eighteen different formulations were screened in ASTM Corrosion Test for Engine Coolants in Glassware (D 1384) with used MIL-A-46153 antifreeze which contained depleted inhibitor ingredients. Two formulations were selected for final testing. Both formulations were similar except that in one sodium silicate was used and in the other, potassium silicate. The formulation with sodium silicate was dropped from further testing when it was discovered that upon sitting for a period of one month the material formed a precipitate. The precipitate does not form in the formulation using potassium silicate.

Results of ASTM D 1384 test and ASTM Method for Simulated Service Corrosion Testing of Engine Coolants (D 2570) show that the formulated additive package used at a 3% concentration in used antifreeze not only gives adequate protection to the six cooling system metals, it is an excellent inhibitor for water. It can also be added to new MIL-A-46153 antifreeze with no deleterious effects. Several military vehicles were selected for a one-year field test and the pH and reserve alkalinity were monitored throughout the test at three-month intervals. The results show that the pH and reserve alkalinity remained at an acceptable level over the one-year period and clearly indicate the coolant was still useable for further service.

It is concluded that the addition of the additive package, Additive, Antifreeze Extender, Liquid Cooling System (MIL-A-53009), to used military antifreeze will allow continued use for a period of time exceeding one year. It has no adverse effect if added to a new fully inhibited antifreeze and is an excellent inhibitor for a water system.
Dynamic Testing of Soldered Joints in Engine Coolants
Authors: Beal RE
Published: December 2008

A dynamic test for soldered joints in a coolant environment has been developed that allows definitive coolant comparison with respect to soldered joint response in service. The test unit consists of a heated pressure vessel, capable of handling temperatures up to 149°C and pressures up to 0.21 MPa, and twelve specimen jigs. Soldered joints are made under controlled conditions and exposed in coolant under static and dynamic stress rupture conditions. Joint failure is measured on timers that trip upon specimen fracture.

Solder alloys selected for the program were 70Pb-30Sn, 95Pb-5Sn, and 97Pb-2.5Sn-0.5Ag materials. Four commercially available coolants were tested with the above solders at selected loads. A series of tests was also conducted to examine the effect of water used in diluting the coolant. Different commercial coolant and water combinations were found to produce variable degrees of corrosion and joint failure. Solder bloom was found to increase in engine coolant at radiator operating temperatures in the presence of applied stresses.
Observations on Aluminum Water Pump Cavitation Tests
Authors: Oakes BD
Published: December 2008

Two water pump cavitation tests are currently used by automotive coolant suppliers that wish to sell coolants to automobile manufacturers in the United States. One test is ASTM Test for Cavitation Erosion-Corrosion Characteristics of Aluminum Pumps with Engine Coolants (D 2809). The other is Ford Laboratory Test for Cavitation Erosion-Corrosion Characteristics of Engine Coolants on Aluminum Coolant Pumps (BL 3-1). Details of the test methods are given in the respective ASTM and Ford publications.

Phosphate is confirmed to have a beneficial effect on cavitation. Silicate is shown to be beneficial when used with borate or benzoate, but it can be detrimental to the performance of phosphate. Materials of construction in the test apparatus, copper primarily, can affect the results obtained in the longer term Ford test. Coolants not particularly subject to cavitation appear to fail the test if copper from the test rig piping deposits inside the water pump. Cavitation is not observed with these coolants in the absence of copper. Coolants truly subject to cavitation will show it regardless of the construction materials in the test rig. Finally, it is observed that coolants that will not pass the ASTM pump test at the specified 1:5 concentration will often do so at a 1:2 concentration.
Miniaturized Disk Bend Test Technique Development and Application
Authors: Manahan MP , Browning AE , Argon AS , Harling OK
Published: December 2008

The objective of miniaturized specimen technology is to enable the characterization of mechanical behavior while using a greatly reduced or minimum volume of material. The significance of this technology is obvious to the nuclear industry where neutron irradiation space is limited and irradiation costs scale with specimen volume. In addition, the substantial advantages resulting from application of this technology in non-nuclear industries are only beginning to be realized.

The initial development of a miniaturized disk bend test (MDBT) for extraction of post-irradiation mechanical behavior information from disk-shaped specimens no larger than transmission electron microscopy samples is described. Central loading with a hemispherically tipped punch is used to measure load/deflection curves to fracture. These load/deflection curves are simulated using finite element analysis. This approach to miniature mechanical property testing is shown to offer the potential for the derivation of uniaxial flow properties.

This paper primarily emphasizes the development of test techniques and procedures; however, results for the determination of uniaxial tensile behavior are presented to demonstrate the validity of the basic methodology. Recommended techniques for specimen design, specimen preparation, experimental design, experimental implementation, and data analysis are presented.
Development of Small Punch Tests for Ductile-Brittle Transition Temperature Measurement of Temper Embrittled Ni-Cr Steels
Authors: Baik J-M , Kameda J , Buck O
Published: December 2008

Small punch tests were developed to determine the ductile-brittle transition temperature of nickel-chromium (Ni-Cr) steels having various degrees of temper embrittlement and various microstructures. It was found that the small punch test clearly shows the ductile-brittle transition behavior of the temper-embrittled steels. The measured values were compared with those obtained from Charpy impact and uniaxial tensile tests. The effects of punch tip shape, a notch, and the strain rate on the ductile-brittle transition behavior were examined. It was found that the combined use of a notch, high strain rates, and a small punch tip strongly affects the ductile-brittle transition behavior. Considerable variations in the data were observed when the small punch tests were performed on coarse-grained steels. Several factors controlling embrittlement measurements of steels are discussed in terms of brittle fracture mechanisms.
Low-Load Microhardness Changes in 14-MeV Neutron Irradiated Copper Alloys
Authors: Zinkle SJ , Kulcinski GL
Published: December 2008

Transmission electron microscopy (TEM) disks of pure copper and copper alloyed with 5 atom% of either aluminum, manganese, or nickel have been irradiated at 25°C with 14-MeV neutrons. Vickers microhardness measurements were obtained as a function of fluence up to a maximum level of 2.2 × 1021 n/m2. Measurements were made at two different values of indenter load (5 and 10 g) in order to facilitate correlations with high-load microhardness data. A simple antivibration test stand was designed which allowed reproducible microhardness results to be obtained independent of background vibrations down to indenter loads of 2 g. The radiation-induced microhardness change at both indenter loads scales linearly with the fourth root of neutron fluence following an incubation fluence. At a fluence of 2 × 1021 n/m2, the microhardness is increased by at least 50% over the unirradiated microhardness value for all four metals. The alloys, in particular Cu-5 Mn, exhibited a shorter incubation fluence and a larger radiation hardening than pure copper. Estimates of the defect cluster density obtained from 10 g microhardness data are in good agreement with TEM observations obtained on these alloys by other researchers. The measured irradiation-induced microhardness change is about 40% less at an indenter load of 5 g than at an indenter load of 10 g for a fluence of 2 × 1021 n/m2. This indicates that irradiation-induced changes in low-load microhardness are dependent on the indenter load; therefore any results which are obtained at low loads should be used with caution.
Wire Tensile Testing for Radiation-Hardening Experiments
Authors: Bradley ER , Jones RH
Published: December 2008

Techniques have been developed for preparing, irradiating, and conducting tensile tests on small-diameter (0.25 to 0.5 mm) wire specimens to determine the effects of high-energy neutron and proton irradiation on mechanical properties. Gage sections were produced electrolytically, and the tensile tests were conducted in an Instron tensile testing machine using a fixture designed to maintain axial alignment and to allow for easy loading of the fragile specimens.

Nickel, niobium, vanadium, and titanium wire specimens were irradiated with T(d,n) neutrons, Be(d,n) neutrons, or 16-MeV protons to fluence levels ranging from 0.2 to 30 × 1021 m−2. The tensile data indicated that yield strength measurements can provide a reliable method of evaluating the hardening produced by high-energy particle irradiations. The precision of the yield strength data ranged from 0.03 to 0.18, depending on radial flux gradients, material grain size, and wire diameter. Greater variations were observed in the elongation and strain-hardening data; these variations were attributed to the tapered gage sections produced by electropolishing. Tensile elongation and work hardening were also strongly dependent on specimen diameter; thus, these properties from small-diameter wire specimens should be used with caution.
Use of Subsized Specimens for Evaluating the Fracture Toughness of Irradiated Materials
Authors: Huang FH
Published: December 2008

The effects of specimen size, temperature, and irradiation on fracture toughness were studied in unirradiated compact tension specimens of Alloy A286 and HT-9 and irradiated specimens of 20% cold-worked Type 316 stainless steel. Techniques for specimen preparation and test procedures were developed using unirradiated specimens of A286 with the specimen size identical to that of irradiated specimens of 20% cold-worked Type 316 stainless steel. Fracture toughness tests on these precracked specimens were conducted at various temperatures, and test results were analyzed using the multiple specimen R-curve method. Owing to irradiation hardening and post-irradiation toughness degradation, sufficient constraint existed in thin irradiated specimens to permit the application of the J-integral approach. Analysis showed the absence of a significant size effect among the specimens tested and that the size requirements for an ASTM valid JIc test were satisfied, indicating that small specimens may be used for post-irradiation fracture toughness testing. The results are discussed in terms of size criteria for valid JIc determination and conditions for J-controlled crack growth.
Effect of Specimen Size and Material Condition on the Charpy Impact Properties of 9Cr-1Mo-V-Nb Steel
Authors: Corwin WR , Hougland AM
Published: December 2008

The degradation of fracture resistance of ferritic steels subjected to neutron irradiation can be qualitatively evaluated by examining the shift in the ductile-to-brittle transition temperature and the drop in the upper-shelf energy as determined in the Charpy impact test. That is an empirical test, however, and its usefulness is derived primarily from either correlation to more quantitative measures of fracture toughness or comparison with other Charpy test results for different materials or conditions of interest. Any departures from the standard testing procedures, including specimen dimensions, will yield results which will vary in some degree from those of a standard test.

In examining the effects of neutron irradiation on the fracture resistance of the high-chromium ferritic steels which are candidates for the first wall of magnetic fusion reactors, it is necessary to severely limit the size of the test specimens to be fit within high-flux test reactors. Impact specimens with cross sections as small as ⅓ by ⅓ cm are employed. To evaluate the effectiveness of small specimens in measuring the relative shift in transition temperature and drop in upper-shelf energy, compared with a standard Charpy specimen, a study of the impact properties of 9Cr-1Mo-V-Nb steel in both the normalized and tempered and the quenched-only condition was conducted. Full-size and various subsize Charpy V-notch specimens of two orientations were examined in both material conditions.

Comparing the test results of the tempered with the embrittled 9-Cr-1Mo-V-Nb steel showed that larger transition temperature shifts and smaller fractional drops of upper shelf were measured with the small specimens relative to the standard-size specimens. Attempts were made to improve the correspondence of data by fracture area and volume normalization. No improvement in the shift or shelf drop was obtained. However, a fair agreement for the higher energy tests of absolute energy was obtained with fracture volume normalization.
Use of Rapidly Solidified Aluminum Alloys in Land Vehicles
Authors: Waldman J
Published: December 2008

The use of aluminum alloys produced by rapid solidification technology (RST) in land vehicles is discussed. Applications of these alloys to both commercial land vehicles (automobiles) and military land vehicles (armored personnel carriers) are presented. Also presented is a discussion on the ingot metallurgy aluminum alloys currently used in land vehicle applications.
Microstructure of Supercooled Submicrometre Aluminum-Copper Alloy Powder
Authors: Ridder SD , Shechtman D
Published: December 2008

Various Al-Cu alloy powder particles were produced by electrohydrodynamic atomization. The particles produced by this process range in size from 3 nm to 2 μm. The microstructure of the submicrometre particles is shown, and a discussion of their cooling rates and solidification history is presented.

The alloys produced included various compositions of aluminum and copper. Extended solid solubility was observed in all the alloys and was dependent on the particle size and concentration. The particles produced from alloy concentrations beyond the equilibrium solubility limit which exhibit segregation-free microstructure probably solidified after undercooling sufficiently to produce the interfacial temperatures and velocities necessary to suppress segregated growth. These aspects of solidification are discussed and estimates of the cooling rates and bulk undercoolings achieved are given. Some of the particles show a transition from partitionless solidification to a segregated, cellular solidification.
Influence of Hydrogen on the Ductility of 7091 and 7090 PM Aluminum Alloys
Authors: Meunier J
Published: December 2008

Two high-strength aluminum alloys, X7091 and X7090, were produced by powder metallurgy (PM) processing, which included gas (air or helium) atomization, cold compaction, hot vacuum degassing, hot compaction, and extrusion. The products were then solution heat treated, water quenched, stress relieved, and aged as follows: Alloy X7091 was aged for 24 h at 120°C plus 4 h at 163°C and Alloy X7090 for 24 h at 120°C plus 1 h at 163°C. The mechanical properties in the longitudinal and transverse directions and the hydrogen (H2) content were then measured.

The author observed that the H2 content of the different products varies from 1 ppm to more than 10 ppm as a function of the quality of the degassing process and that, though the mechanical properties (yield strength, ultimate tensile strength, and elongation) are not affected in the longitudinal direction, the elongation in the transverse direction can decrease from 10% for an alloy with low H2 content to 0% for an alloy with high H2 content.

It is, however, difficult to correlate the hydrogen content with ductility: a high-H2 alloy can have good ductility when highly oxidized. This phenomenon can be explained by a beneficial hydrogen getter effect by the oxide. It seems, then, that the best way to characterize the soundness of the PM aluminum alloys is by their hydrogen and oxygen contents.
Powder Metallurgy Processing of Aluminum Alloy 7091
Authors: Griffith WM , Kim Y-W , Froes FH
Published: December 2008

Aluminum alloys produced by powder metallurgy (PM) processing have the potential to solve many material problems in aerospace systems. However, to optimize fully the performance of these materials, strict processing control is required. For example, the breakup and redistribution of oxides, which is key to achievement of maximum properties, is directly related to vacuum degassing, hot pressing, and subsequent working of the material. An analysis of each of these steps is reviewed for aluminum PM Alloy 7091 with respect to oxide breakup and distribution.
Dynamic Compaction of Rapidly Solidified Aluminum Alloy Powders
Authors: Sears JW , Miller DJ , Fraser HL
Published: December 2008

Dynamic powder compaction has been investigated as a means of consolidating aluminum alloy particulate. Thus, the aluminum alloy 7091 has been compacted using this technique, and the dependence of both compaction density and hardness on the projectile velocity have been determined. The consolidated material has been studied using analytical (transmission) electron microscopy, both in the as-compacted state and after subsequent heat treatment at 523 and 723 K. In the as-compacted specimens, some evidence for interparticle melting has been observed. For the heat-treated material, decomposition of the as-solidified and compacted microstructure has been observed and the products of this decomposition have been characterized.
Effects of Alloy Chemistry on Superplastic Forming of Rapid-Solidification-Processed Aluminum-Lithium Alloys
Authors: Lederich RJ , Meschter PJ , Sastry SML
Published: December 2008

The superplastic forming characteristics of rapid-solidification-processed (RSP) Al-3Li-based alloys containing varying amounts of copper, magnesium, cobalt, and zirconium and processed by different thermomechanical sequences were investigated. Their final microstructures were strongly dependent on the processing treatment and alloy composition. All the zirconium-containing alloys were processed to have a fine subgrain microstructure. These alloys deform predominantly by dislocation glide and climb processes and by subgrain boundary motion, and they exhibit up to 400% elongation, which is sufficient for many commercial forming applications. Cavitation was suppressed, and the mechanical properties were not affected by forming. A thermomechanical processing sequence was established that develops a completely recrystallized fine grain microstructure in the Al-Li-Cu-Zr alloys. The alloys with this recrystallized microstructure have excellent formability.
Thermomechanical Treatment of 2124 PM Aluminum Alloys with Low and High Dispersoid Levels
Authors: Sarkar B , Barry Lisagor W
Published: December 2008

The effects of thermomechanical treatment (TMT) on the mechanical properties and metallurgical structure of 2124 powder metallurgy (PM) aluminum alloys prepared from rapidly solidified powders were investigated. The alloys were prepared by using a standard canning/vacuum degassing/hot consolidation/extrusion sequence. Two compositions, with manganese contents of 0.5 and 1.5%, were investigated to examine the effects of low and high dispersoid levels.

The results indicate that significant improvements in strength can be accomplished through TMT for this PM alloy system with little loss in toughness. The increase in strength observed is attributed to the presence of much finer, more homogeneous S′ precipitation than that observed without TMT. Rolling deformation at room temperature resulted in some tendency for nonuniform (planar) deformation and resulted in slightly lower notch strength values. The lower notch strengths observed in the higher manganese composition were attributed to the coarser, more dense dispersoids observed in this material.
Developments in Premium High-Strength Powder Metallurgy Alloys by Kaiser Aluminum
Authors: Ping SW
Published: December 2008

Powder metallurgy (PM) development by the Kaiser Aluminum & Chemical Corp. began in 1953 with a U.S. Air Force contract to make high-modulus, high-temperature alloys. From 1957 to 1959, alloy supersaturation studies were undertaken on binary, ternary, and more complex alloys. The development of powder products with good room-temperature properties followed in 1959 to 1961. Some of the Al-Zn-Cu-Mg-based PM alloy extrusions had tensile yield strengths of > 760 MPa (> 110 ksi). In the late 1960s, the high-strength, heat-treatable 7XXX alloy PM61 was developed. In the early 1970s, an improved powder vacuum degassing method was developed, which removes essentially all of the volatile contaminants at lower temperatures and shorter times than required by previous vacuum degasification processes. Using this new degassing technology, PM61 alloy seat track extrusions were produced for use in Boeing 727 aircraft in 1977. Two new alloys, PM62 (a 7XXX type) and PM63 (a 2XXX type) were developed in 1976 and 1977; these alloys exceeded the minimum allowable strength levels of high-strength ingot metallurgy (IM) 2XXX and 7XXX alloy extrusions by about 30%. During 1978 and 1979, Alloy PM64, a 7XXX alloy having improved damage tolerance, was developed. A subsequent U.S. Navy contract with the Northrop Corp. showed that PM64 alloy extrusions exhibited a combination of properties superior to those of contemporary high-strength IM or PM alloys. Recently, slight chemistry and fabrication modifications of PM63 and PM64 alloys have produced significant improvements in fatigue crack growth resistance without adversely affecting other properties. It has also been demonstrated that PM64 alloy sheet has attractive superplastic properties.