bluuebunny/crossref_metadata_2025 huggingface dataset:
Irradiation-Induced Swelling in AISI 316 Steel: Effect of Tensile and Compressive Stresses
Authors: Lauritzen T , Vaidyanathan S , Bell WL , Yang WJS
Published: December 2008

Effects of bending stresses on the swelling behavior of 20% cold worked AISI 316 steel were studied in material irradiated to moderately high fluences in EBR-II. Specimens used in this investigation consisted of beams subjected to four-point bending during irradiation. Fluences as high as 1.5 × 1023 n/cm2 (E > 0.1MeV) were accumulated at temperatures ranging from 412 to 458°C. The beams were subsequently sectioned to isolate regions of tensile, compressive, and neutral loading for examination by transmission electron microscopy. A complete characterization of swelling in each of the three regions was conducted to assess the influence of these stress states on the magnitude of swelling. A detailed microstructural evaluation of the material was also made to attempt to relate swelling differences with physical changes in the alloy.

The results of this investigation confirm earlier experimental data that showed swelling in AISI 316 steel to be enhanced by the application of stress during irradiation and that the magnitude of swelling is independent of the sign of the applied stress. The results also show that increases in swelling can be correlated with either more or larger voids depending upon the total strain incurred. This suggests that the mechanism for stress-enhanced swelling in this alloy may be a sensitive function of the magnitude of the applied stress.
Gas-Bubble Growth Mechanisms in the Analysis of Metal Fuel Swelling
Authors: Gruber EE , Kramer JM
Published: December 2008

Under steady state conditions, irradiation resorption of fission gas from bubbles limits the swelling rates of metallic fast-reactor fuels to relatively small values. During transient thermal excursions, however, resorption effects diminish relative to thermal kinetics. Various bubble-growth mechanisms then become important components of the swelling These mechanisms include growth by diffusion, for bubbles within grains and on grain boundaries; dislocation nucleation at the bubble surface, or “punchout”; and bubble growth by creep. Analyses of these mechanisms are presented and applied to provide information on the conditions and the relative time scales for which the various processes should dominate fuel swelling. The results are compared to a series of experiments in which the swelling of irradiated metal fuel was determined after annealing at various temperatures and pressures. The diffusive growth of bubbles on grain boundaries is concluded to be dominant in these experiments.
Ion Damage in a Fe-10Cr-6Mo-0.5Nb Ferritic Steel
Authors: Farrell K , Lee EH
Published: December 2008

An annealed-and-aged ferritic steel containing fine NbC precipitates and relatively coarse particles of Laves phase was bombarded with 4-MeV iron ions to 100 displacements per atom (dpa) at 400 to 600°C. Much of the damage structure consisted of dislocation tangles that coarsened with increasing temperature. Cavity formation began at 450°C, peaked at about 535°C, and was absent at 600°C. Maximum swelling was only 0.2%. The Laves particles exhibited recoil dissolution and restructuring. Bombardments with Fe + He + D or Fe + He beams at ratios of 10 atomic parts per million (appm) He/dpa and 45 appm D/dpa introduced high concentrations of very small bubbles and comparatively few larger, bias-driven cavities. The latter were initiated at bubble clusters on NbC particles. Maximum swelling of 0.75% occurred at 550°C. Recoil dissolution of the Laves phase was retarded by the gases. Large critical cavity sizes and unbalanced dislocation and cavity sink strengths contribute to low swelling of this alloy.
Fatigue Crack Growth and Lifetime Trends in Injection Molded Reinforced Thermoplastics
Authors: Mandell JF , McGarry FJ , Li C-G
Published: December 2008

Glass and graphite fiber reinforced injection molded thermoplastics contain very short fibers, resulting in matrix/interface dominated properties. Molded parts typically fail by propagation of a single dominant crack. A fiber avoidance crack growth model is presented in which the crack extends by the coalescence of isolated failure zones; the crack tip process zone dimension is fixed by the microstructure (fiber) size and so does not change with test conditions or Kmax in fatigue crack growth. Fracture toughness data for several materials correlate with this model. Fatigue crack growth follows a power law relationship with an exponent close to 4 for the pure matrices and 7 to 8 for the composites. The threshold KI values where cracks will not grow are a much higher fraction of the fracture toughness for the composites than for most unreinforced polymers or metals. The trends of S-N curves for unnotched molded bars follow the same exponent as observed in fatigue crack growth. Shifts in the pure matrix failure mode in fatigue are reflected in the local failure mode of the composites.
A Hierarchical Model-Based Control System for Inspection
Authors: Hopp TH , Lau KC
Published: December 2008

A control system architecture for three-axes coordinate-measuring machines, using hierarchical task-decomposition techniques, is described. This architecture is based on real-time, sensory-interactive control concepts developed at the National Bureau of Standards (NBS). An inspection program consists of a series of high-level goals to be satisfied. Goals are satisfied when specified information has been obtained regarding the part. There is a decision hierarchy, each level of which provides logic for partially decomposing goals into simpler goals. The control system executes the inspection program by interpreting the decision hierarchy logic. The lowest level of the decision hierarchy generates primitive coordinate-measuring machine actions, which are directly executed. A world model hierarchy executing in parallel with the task decomposition hierarchy provides information which aids in the decomposition decisions at each level. The world model is derived from a combination of prior knowledge of the part and observations gathered during inspection. The use of a world model allows an inspection task to adapt to the particular part being inspected.

It is expected that control architecture described here will provide new research opportunities in various areas of computer-aided design/computer-integrated manufacturing (CAD/CAM). The experience at NBS in using a similar architecture for robot control systems indicates that this system can naturally incorporate new inspection technology such as continuous tracing and vision. The system will also be used in various research efforts in the area of standards. These include the development of techniques for incorporating quality assurance standards into inspection tasks, development of languages for communicating inspection programs between different systems, and identifying n new data requirements for CAD representations of parts.
Strain-Hardening Effects on Fracture Toughness and Ductile Crack Growth in Austenitic Stainless Steels
Authors: Balladon P , Heritier J , Jarboui C
Published: December 2008

The influence of cyclic and monotonic strain hardening on fracture toughness and ductile crack growth properties of 316 L stainless steel is determined using JIc and J-R curves. Cyclic strain hardening is performed by cyclic loading at different levels during precracking of specimens used for J-R tests. Monotonic strain hardening is done by controlled hot rolling of plate steel. The results obtained show that the fracture toughness is decreased by both cyclic and monotonic strain hardening. This decrease mainly affects crack initiation resistance (JIc) in the case of cyclic loading and only slightly influences crack growth resistance (dJ/da). For monotonic strain hardening, both JIc and dJ/da are strongly reduced at room and elevated temperatures. An attempt is made to determine the main factors responsible for these effects.
A Similitude Criterion for Fatigue Crack Growth Modeling
Authors: Broek D
Published: December 2008

Instead of the stress intensity factor, the crack tip plastic strain range is proposed as a similitude parameter and as a basis for fatigue crack growth analysis. Quantitative analytical evaluation shows that an effective stress intensity that accounts for differences in crack tip plastic strain range can be rationally derived and used to account for the fatigue crack threshold, certain small crack behavior, and retardation.
Slow-Strain-Rate Testing of Al 7075-T6 in Controlled Atmospheres
Authors: Khobaib M , Lynch CT
Published: December 2008

The stress-corrosion-cracking (SCC) susceptibility of Al 7075-T6 alloys has been studied in a controlled-atmosphere chamber utilizing the slow-strain-rate technique. The effects of high-humidity air with small additions of sulfur dioxide, nitrogen dioxide, and surface salts in different combinations have been investigated to predict the behavior of industrial environments. The slow-strain-rate technique has been used to optimize the simulated environments which result in accelerated crack growth and failure by SCC in high-strength Al 7075-T6 alloy. These controlled environmental tests provide initial data on the environmental susceptibility needed for the development of realistic accelerated-corrosion testing methods. The design of the environmental chamber for providing controlled atmospheres is discussed and initial experimental results are presented.

Most tests were conducted at 80 to 90% relative humidity. The SO2 concentration was varied from 10 to 1000 ppm, while NO2 was maintained to 100 ppm. Small amounts of surface salts were obtained by rapid immersion in aqueous salt solutions. The susceptibility of the alloy shows significant differences that are dependent upon the specific environmental contaminants. Synergistic effects in several environments were found to maximize the environmental effects upon crack growth in stress corrosion. In a related study, these effects were demonstrated in corrosion-fatigue experiments under similar conditions. The qualitative estimates of embrittlement in the fracture surfaces were consistent with slow-strainrate results. The data provide the basis for the development of accelerated corrosion tests in realistic atmospheres.
Variation in the Strain Anisotropy of Zircaloy with Temperature and Strain
Authors: Hindle ED , Worswick D
Published: December 2008

The strong crystallographic texture which is developed during the fabrication of zirconium-based alloys causes pronounced anisotropy in their mechanical properties, particularly deformation.

The tendency for circular-section tension specimens with a high concentration of basal poles in one direction to become elliptical when deformed in tension has been used in this study to provide quantitative data on the effects of both strain and temperature on strain anisotropy. Tension tests were carried out over a temperature range of 293 to 1193 K on specimens machined from Zircaloy-2 plate. The strain anisotropy was found to increase markedly at temperatures over 923 K, reaching a maximum in the region of 1070 K. The strain anisotropy increased with increasing strain in this temperature region.

The study was extended to Zircaloy-4 pressurized-water reactor fuel cladding by carrying out tube swelling tests and evaluating the axial deformation produced. Although scatter in the test results was higher than that exhibited in the tension tests, the general trend in the data was similar.

The effects of the strain anisotropy observed are discussed in relation to the effects of temperature on the ductility of Zircaloy fuel cladding tubes during postulated large-break loss-of-coolant accidents.
Corrosion of Steel in Brick Masonry
Authors: Grimm CT
Published: December 2008

Under present design standards steel ties, anchors, fasteners, joint reinforcement, reinforcing bars, and structural steel lintels and shelf angles in exterior masonry walls corrode at a rate which gives them a life expectancy of 5 to 70 years. Implementation of recommendations for improved design standards could double their life expectancy. Seventy references are cited.
Desiccation Cracking of Soil Barriers
Authors: Kleppe JH , Olson RE
Published: December 2008

Compacted soil liners have been used to retard leakage of fluids from burial sites. If allowed to desiccate, such liners may shrink, crack, and lose their integrity. As a result of the expense and control problems associated with field tests, an initial laboratory study was made of shrinkage, cracking tendency, and hydraulic conductivity of various compacted clay/sand mixtures. The study showed that desiccation shrinkage increased linearly with compaction water content and was unaffected by density. Soaking prior to desiccation increased strains markedly for specimens compacted dry of optimum. Shrinkage strains greater than 10% should cause serious problems in the field. Clay/sand mixtures were prepared which were crack resistant and which had low hydraulic conductivities.
Relationships Between Vehicle Speed, Ride Quality, and Road Roughness
Authors: Paterson WDO , Watanatada T
Published: December 2008

The relationship of vehicle response to road roughness and speed is quantified from two major data sets obtained from response-type roughness measuring systems used in Brazil. The average rectified slope and average rectified velocity (ARV) response statistics are expressed in terms of speed and a reference roughness scale in a generalized relationship applicable to most road surfaces. Corrugated surfaces require explicit analysis. The effect of road roughness on average traffic speed, that is, the driver's response, is quantified as a function of the vehicle's ARV response and vehicle type; the limiting values estimated for six vehicle classes range from 150 to 280 mm/s. The issues of roughness measurement speed, a reference speed for a universal roughness scale, and the relationship between road roughness and vehicle operating costs are discussed.
Combustible Linings and Room Fire Growth—A First Analysis
Authors: Magnusson SE , Sundström B
Published: December 2008

A computational procedure has been developed to correlate a full-scale room fire test process and results from the proposed International Organization for Standardization (ISO) small-scale laboratory tests. The analysis assumes that the combustible lining material covers ceiling and walls. Derived material characteristics and test room time lag factors are used as input data to an uncomplicated mathematical expression, essentially describing the full-scale test fire process as a concurrent flame spread phenomenon. Undetermined parameters in the model have been derived using linear regression analysis and results from seven full-scale room tests. In these room tests, the tested materials were of such thickness that no burning through occurred. Using results from the regression analysis, a simulation of the fire growth behavior can be carried out, including the adjustments needed due to transportation time lags and instrument response time. The predictive capability was thought acceptable, but further experimental confirmation and sensitivity studies are needed to assess the inherent variability. Qualitatively the regression equation predicted the same relative ranking of materials as the room test.

For thin surface finish materials on a noncombustible base, it was possible to derive a radically simple expression to be used as indication of the risk of flashover. Again, the final usefulness only can be evaluated on the basis of further experimental evidence.

In summary, it is thought that a first step has been taken in the efforts to use results from small-scale tests to rationally predict full-scale fire growth (for one specified scenario) and rank materials.
Design of Buildings for Prescribed Levels of Structural Fire Safety
Authors: Harmathy TZ , Mehaffey JR
Published: December 2008

Two techniques are outlined for designing buildings to meet prescribed probabilities of structural failure in fire. They require input information for seven variables; three of these variables, fire load, ventilation, and (experimentally determined) fire resistance, are random variables. Information on the randomness of the first and third variables is available. The second variable, ventilation, is taken into account with its most adverse value.
Fatigue Life Estimates for a Simple Notched Component Under Biaxial Loading
Authors: Fash JW , Socie DF , McDowell DL
Published: December 2008

Three-dimensional stress-strain fields are routinely determined for complex components using elastic and elastic-plastic finite element models. Although the local stress-strain response can be easily determined, the proper approach to strain based multiaxial fatigue analysis is not clear. Several multiaxial fatigue theories have been suggested, but there exists a lack of consensus on which model is most appropriate. To clarify the situation, experiments have been performed on two different multiaxial specimen geometries. Results are compared with theoretical predictions.

Thin-walled tube specimens have been tested using combined in-phase tension-torsion loading. This specimen geometry has a simple uniform stress-strain state. Tests were also performed using a solid notched shaft specimen subjected to inphase torsion-bending loads. Stress-strain gradients exist in the notch root. Local multiaxial stress-strain fields were determined using an elastic-plastic finite element model.

Five current multiaxial strain based fatigue theories have been developed to correlate the experimental results. Fatigue life estimates were based upon uniaxial strain controlled fatigue data.

Correlations for the thin-walled tube test series were within a factor of 3 in fatigue life. For the notched shaft specimen with the more complex stress-strain state, life estimates were in error by a factor of 10 in fatigue life. This suggests that the effects of geometry are as important as the selection of the fatigue theory. Much additional work needs to be done to understand the effect of notches in multiaxial fatigue before these methods can be routinely implemented by designers.
Creep and Ageing Interactions in Biaxial Fatigue of Type 316 Stainless Steel
Authors: Kandil FA , Miller KJ , Brown MW
Published: December 2008

A high-strain, biaxial (tension/torsion) fatigue study has been conducted on Type 316 stainless steel at 550°C. The tests were under strain control, some with dwell periods up to 10 min at the positive strain peaks. The deformation and fracture behavior under these conditions revealed a strengthening effect due to the fast carbide precipitation which extended life in some cases. Also it is shown that the form of the multiaxial fatigue failure criterion, modes, and directions of cracking were functions of hold time. The multiaxial cyclic stress-strain curve is best described in terms of shear stress and strain components on the maximum shear plane for a given hold time.
Damage Growth Under Nonproportional Loading
Authors: Hayhurst DR , Leckie FA , McDowell DL
Published: December 2008

The objective of the study is to quantify the growth rate of damage which occur when materials are subjected to variable nonproportional loading at elevated temperatures. Fast and slow nonproportional cyclic tests are performed on circular tubes and observations made on the deformation history, life, and nature of damage accumulation. The results are then related to a general theory of creep-fatigue damage description which has recently been formulated.
Use of Biochemical Measurements to Detect Pollutant-Mediated Damage to Fish
Authors: Neff JM
Published: December 2008

The use of enzyme activity or concentration of biochemicals in the tissues to detect pollutant stress in fish is reviewed. Of the many biochemical parameters which have been measured, most are of limited value at present, primarily because correlations between biochemical effects and significant deleterious effects in the fish population have not been established. Characteristics of the metallothionein and mixed-function oxygenase systems and activity of acetylcholinesterase and delta amino levulinic acid dehydratase in fish tissues or blood may be useful for identifying fish which have been exposed to particular classes of pollutants. Some blood enzymes and biochemicals are useful for diagnosing liver damage in fish. Biochemical composition and concentrations in the blood and tissues of fish. Biochemical composition and concentrations in the blood and tissues of fish from polluted habitats differ in characteristic ways from those of fish of the same species from nearby clean areas. Some of these differences show promise for use in assessing damage to fish populations.
How Representative are the Data Sets Used to Derive National Water Quality Criteria?
Authors: Seegert G , Fava JA , Cumbie PM
Published: December 2008

One of the key assumptions implicit in developing national water quality criteria is that the data base used to derive the criteria includes data from a reasonable cross section of the aquatic communities to be protected. This requires testing not only a large number of species but those species that represent a variety of taxonomic and functional groups. Implicit also is the assumption that the species tested represent the full range of sensitivities expected in the population as a whole and that neither overly sensitive nor resistant species are unduly represented in the data base. Examination of the national toxicity data base indicated that the toxicity data which it contains does not meet these assumptions because (for 21 priority pollutants) 40% of the data are on a few regularly tested species such as bluegill and fathead minnow and one quarter of the data are on only two families. Daphnidae and Salmonidae. Furthermore, for many chemicals, many of the species that have been tested are restricted to the northeastern and/or upper midwest portions of the United States. The problem of nonrepresentative testing is further complicated by the fact that toxicity data for some of the commonly tested species (e.g., rainbow trout) are often replicated and verified by several investigators, whereas data on other species are not. This is particularly true of the toxicologically sensitive species. Finally, the evidence suggests that sensitive species may be overrepresented in the national toxicity data base.

The net result is that we now have a great deal of data about a few species, but little or no data about the vast majority of species. Nor do the data available necessarily represent a reasonable cross section, based on sensitivities or ecological importance. The above assertions will be supported using examples from the national data base and from data bases on individual chemicals. This indicates a need for information on a wider variety of organisms in order for the national data base to be representative of the full range of sensitivities expected in the population as a whole. While it is recognized that it will not be possible to conduct tests on all species, the underlying distribution of the data base should be understood before appropriate statistical methods can be developed to derive national water quality criteria for the protection of aquatic life. This may require some testing of representative species from sensitive and insensitive groups. Additional implications of the actual distribution of the national toxicity data base will be discussed.
Delamination Crack Growth in Composite Laminates
Authors: Wang ASD , Slomiana M , Bucinell RB
Published: December 2008

This paper presents in detail the application of an energy method to describe a class of delamination crack growth problems found in polymer-based composite laminates. The energy method is derived from the general concepts of classical fracture mechanics. When used judiciously and with proper interpretation of the physical factors pertinent to the crack growth process at the lamina(ply) level, the method describes well delamination growth behavior in laminates that are subjected to monotonically (static) or cyclically(fatigue) applied loads or to both. Both could be in tension or in compression.

The basic method can be used to describe not only one-dimensional delamination growth (for example, free edge delamination) but also two-dimensional delamination growth (contoured delamination). Laboratory test results using laminates made of an AS-3501-06 graphite epoxy system are presented along with analytically predicted results. Excellent correlations between analytical and experimental results are obtained.
A Fracture Mechanics Approach for Designing Adhesively Bonded Joints
Authors: Johnson WS , Mall S
Published: December 2008

An analytical and experimental investigation was undertaken to determine if the adhesive debond initiation stress could be predicted for arbitrary joint geometries. The analysis was based upon a threshold total strain-energy-release rate (Gth) concept. Two bonded systems were tested: T300/5208 graphite/epoxy adherends bonded with either EC-3445 or FM-300 adhesive. The Gth for each adhesive was determined from cracked-lap-shear (CLS) specimens by debond initiation tests. Finite-element analyses of various tapered CLS specimen geometries predicted the specimen stress at which the total strain-energy-release rate (GT) equaled Gth at the joint tip. Experiments verified the predictions. The approach described herein predicts the maximum stress at which an adhesive joint can be cycled yet not debond. Total strain-energy-release rate appeared to be the driving parameter for cyclic debonding and debond initiation in structural adhesives, and debond initiation and growth were found to occur with virtually no peel stress present.
Repeatability of Mixed-Mode Adhesive Debonding
Authors: Everett RA , Johnson WS
Published: December 2008

An experimental study was undertaken to assess the repeatability of debond growth rates in adhesively bonded joints subjected to constant-amplitude cyclic loading. This was done by comparing debond growth rates from two sets of cracked-lap-shear specimens that were fabricated by two different manufacturers and tested in different laboratories. The fabrication method and testing procedure were identical for both sets of specimens. The specimens consisted of aluminum adherends bonded with FM-73 adhesive. Critical values of strain-energy-release rate were also determined from specimens that were monotonically loaded to failure. The test results showed that the debond growth rates for the two sets of specimens were within a scatterband similar to that observed in fatigue crack growth in metals. Cyclic debonding occurred at strain-energy-release rates that were more than an order of magnitude less than the critical strain-energy-release rate in static tests.
Static Behavior of Variably Cemented Beach Sands
Authors: Rad NS , Clough GW
Published: December 2008

The surface of the seafloor is covered by sediments consisting of or containing calcareous, siliceous, or argillaceous soils. These sediments are frequently exposed by tectonic uplift or sea level lowering and usually exhibit a degree of cementation. In coastal areas and in a consolidated form they can stand at steep angles and in bluffs as high as 150 m. Although apparently strong, they tend to lose most, if not all, of their strength at the time of failure resulting in sudden and complete collapse.

This paper presents selected test results obtained during laboratory investigation concerning the effects of cementation on the behavior of soils. Utilizing block sampling techniques, naturally occurring cemented soils were sampled from the bluffs along the Pacific coast south of San Francisco, CA. The sands are of quaternary and tertiary marine origin and are classified as weakly or moderately cemented. Static strain-controlled drained and undrained triaxial tests were performed on samples confined under different pressures. Thin sections and electron micrographs were prepared to assess agents of cementation.
Ceramic Fracture Features, Observations, Mechanisms, and Uses
Authors: Rice RW
Published: December 2008

The character and occurrence of mist, hackle, and crack-branching features on ceramic fractures are reviewed and possible mechanisms for causing these features are discussed. Besides glass and polycrystalline fractures, substantial attention is paid to fractures of ceramic crystals, for which new data are presented and similarities shown to fractures of brittle metal crystals. Distinct geometrical effects exhibited by crystal fracture features are illustrated and discussed, as are the variable distances from fracture origin to the onset of features such as mist.

Crack branching of ceramics, which is suggested to be the merging of hackle, is shown to follow the same type of relations as for the onset of mist and hackle. If there is rebranching, it tends to occur at multiples of the original branching distance. Substantial data (again much of it new) show that branch angles are similar for a wide variety of ceramics as well as for brittle fracture of metals. Branch directions are shown to depend on the nature of the test specimen (or crystal directions), and biaxial testing is shown to increase branch angles over those for uniaxial flexure of tension testing. Observations, mechanisms, and effects of intergranular versus transgranular fracture are discussed. The determination and character of flaws causing fracture are summarized, and questions concerning their behavior are raised (for example, effects of complex flaws and of mixed-mode failure).
Scanning Electron Microscopy Techniques and Their Application to Failure Analysis of Brittle Materials
Authors: Healey JT , Mecholsky JJ
Published: December 2008

The applicability of scanning electron microscopy (SEM) to failure analysis of glasses, glass ceramics, and polycrystalline ceramic materials is presented. The principle electron operational modes include the secondary electron mode and the backscattered electron mode, where the traditional backscattered electron image obtained from a negatively biased Everhart-Thornley detector is compared with the topographical and compositional backscattered electron images obtained from the newer solid-state backscattered electron detectors. Both the energy-dispersive and wavelength-dispersive X-ray analysis modes and their relation to failure analysis are presented.

The principles of fracture mechanics are combined with the fracture surface analysis to illustrate the correlation between the fracture surface features and fracture mechanics. Examples of phase-separated glasses will show the ability to determine the propagation path with respect to the phase-separated regions. Glass ceramic fracture toughness samples will be used to illustrate the ability to observe the microstructure and fracture features independently using backscattered electron imaging techniques. Ceramic samples will be used to show the applicability of determining failure mode (transgranular versus intergranular) as well as interaction with twinning and second phases.
Analysis of Failures Associated with Intergranular Fracture
Authors: Pellegrino JV , McCartney RF
Published: December 2008

Intergranular fracture is usually the most easily recognizable mode of fracture, but determining the cause may be quite difficult. Although fractography identifies the presence of intergranular fracture, a correlation of both fractographic and metallographic features should be obtained to aid in identifying the mechanism responsible.

Case histories of failure analyses in which intergranular fractures were observed and were attributed to a variety of mechanisms are presented and include (1) liquid-metal embrittlement of an AISI 1070 rod caused by copper pickup during processing, (2) liquid-metal embrittlement of a low-carbon steel caused by lithium in service, (3) liquid-metal embrittlement of a platinum and platinum-rhodium thermocouple caused by a low-melting platinum-silicon eutectic that formed in service, (4) fracture of a steel-strand wire-rope caused by an area of untempered martensite, (5) “rock candy” brittle fracture of a steel casting caused by the presence of aluminum nitride at the solidification grain boundaries, and (6) brittle fracture of heat-treated bolts manufactured from columbium-treated fine-grain AISI 1541 steel caused by the presence of a columbium film at prior-austenite grain boundaries.

The investigative techniques used included light microscopy, scanning electron microscopy, energy-dispersive spectroscopy, electron diffraction, and secondary-ion mass spectroscopy.
In-Reactor Creep of Selected Ferritic Alloys
Authors: Puigh RJ
Published: December 2008

In-reactor creep data to a peak fluence of 5.7 × 1022 neutrons (n)/cm2 (E > 0.1 MeV) for irradiation temperatures between 380 and 570°C have been obtained for the ferritic alloys HT9, 9Cr-1Mo, and 2¼Cr 1Mo. Also, in-reactor creep data for HT9 has been obtained at 650°C at a fluence of 2.9 × 1022 n/cm2 (E > 0.1 MeV). For irradiation temperatures less than 520°C, the creep strains for all ferritic alloys are small and less than predicted for 20% cold-worked Type 316 stainless steel. At 570°C, thermal creep mechanisms become important and 2¼Cr-1Mo loses its creep resistance. HT9 loses its creep resistance at 650°C and exhibits large diametral strains (>24%).
Swelling of Austenitic Iron-Nickel-Chromium Ternary Alloys During Fast Neutron Irradiation
Authors: Garner FA , Brager HR
Published: December 2008

Swelling data are now available for 15 iron-nickel-chromium ternary alloys irradiated to exposures as high as 110 displacements per atom (dpa) in Experimental Breeder Reactor-II (EBR-II) between 400 and 650°C. These data confirm trends observed at lower exposure levels and extend the generality of earlier conclusions to cover a broader range of composition and temperature. It appears that all austenitic iron-nickel-chromium ternary alloys eventually approach an intrinsic swelling rate of ∼1%/dpa over a range of temperature even wider than studied in this experiment. The duration of the transient regime that precedes the attainment of this rate is quite sensitive to nickel and chromium content, however.

At nickel and chromium levels typical of 300 series steels, swelling does not saturate at engineering-relevant levels. However, there appears to be a tendency toward saturation that increases with declining temperature, increasing nickel and decreasing chromium levels.

Comparisons of these results are made with those of similar studies conducted with charged particles. Conclusions are then drawn concerning the validity of charged particle simulation studies to determine the compositional and temperature dependence of swelling.
Swelling of Microstructure of Neutron-Irradiated Titanium-Modified Type 316 Stainless Steel
Authors: Seran JL , Naour LL , Grosjean P , Hugon MP , Carteret Y , Maillard A
Published: December 2008

The analysis of the behavior of fuel pins irradiated in the same Rapsodie subassembly, shows that titanium has a marked beneficial effect on the swelling resistance of cold-worked Type 316 stainless steel in a wide temperature range. This effect is particularly visible at high temperature since cold-worked Type 316 titanium does not swell above 550°C up to a dose of 100 French displacements per atom (dpaF)(∼74 dpa NRT).

The results obtained on samples irradiated in a Rapsodie experimental rig give us confirmation of the good behavior of cold-worked Type 316 titanium stainless steel that swells less and at lower temperature than other steels of the Type 316 series such as solution-annealed Type 316 titanium or aged solution-annealed Type 316 titanium.

The swelling differences between some of these materials can be associated with different microstructures that are also very different from the ones obtained on the unirradiated steels aged for the same time and temperature conditions.
Solute Segregation and Void Formation on Grain Boundaries in Electron-Irradiated Type 316 Stainless Steel
Authors: Ohnuki S , Takahashi H , Takeyama T
Published: December 2008

Radiation-induced segregation and void formation on grain boundaries in titanium-modified Type 316 stainless steel were investigated by electron irradiation and X-ray microanalysis (EDX). Strong enrichment and depletion of solutes were observed on grain boundaries during irradiation. Moreover, preferential void formation on grain boundaries occurred and grain boundary migration was induced by the irradiation. These facts indicate that grain boundaries act as preferential sinks for radiation-induced point defects, and the sink behavior may be changed by the development of the segregation under irradiation.
Influence of Composition on Steady-State Void Nucleation in Irradiated Alloys
Authors: Esmailzadeh B , Kumar AS
Published: December 2008

The major features of the compositional dependence of radiation-induced swelling of iron-nickel-chromium and iron-nickel-chromium-silicon alloy systems are reproduced using a model proposed by Garner. The model asserts that the major compositional dependence of radiation-induced swelling can be explained by the compositional dependence of the effective vacancy diffusion coefficient, Dveff. The primary influence of composition resides in the transient regime of swelling and is related to the effect of Dveff on the rate of void nucleation.

Measured variations in elemental diffusivities with composition and temperature are used along with the KWR nucleation theory to calculate the steady-state void nucleation rate. The nucleation rate is inversely proportional to the duration of the transient regime at any given temperature. Void nucleation rate is found to depend strongly on the silicon content, and to a lesser extent on the nickel and chromium contents.
Fractographic Analysis of Biaxial Failure in Ceramics
Authors: Mecholsky JJ , Rice RW
Published: December 2008

Borosilicate and silica glass, Pyroceram 9606 glass ceramic, and polycrystalline magnesium fluoride ceramic disks were biaxially stressed and the fracture surfaces examined to determine the size of the fracture surface features. The fracture stress (σ)-fracture mirror radii (rj) relationship σjm=Mj where Mj are the mirror constants (j = 1, 2, 3) and m is constant, usually 0.5, is shown to hold for uniaxial, flexural, and biaxial loading conditions. This implies that any local differences of the stress state at the fracture-initiating site are dissipated by the time the crack-front forms mist, hackle, and crack branching, making measurement of the boundaries of these features a general fracture characteristic.
Factors Affecting the Stress Corrosion Cracking of Austenitic Stainless Steels Under Thermal Insulation
Authors: McIntyre D
Published: December 2008

Fundamental factors affecting the stress corrosion cracking (SCC) of stainless steels under thermal insulation will be reviewed. Specific topics are susceptible alloys, problem temperature ranges, sources of chloride ions, effect of halides other than chlorides, effect of geographical location, effect of potential, pH and buffering agents, mechanisms of concentration, and mechanisms of inhibition. Field experience with closed cell versus wicking type insulation will be discussed. The effectiveness of the weather barrier in preventing SCC under insulation will be discussed in light of maintenance procedure and detail design practice.
Failure of Type 316 Stainless Steel Nozzles in Contact with Fire Retardant Mastic
Authors: Moniz BJ , Ritter MC
Published: December 2008

Two vertical American Iron and Steel Institute (AISI) 316L (Unified Numbering System [UNS] S31603) stainless steel (SST) nozzles on the head of a process vessel operating at 120°C leaked after six years in service. It has been plant practice to apply mastic reinforced with glass cloth as a sealer over insulation around nozzles on vessel heads. The cracking occurred where the fire retardant brominated mastic met the nozzles. Chloride stress corrosion cracking developed when the mastic seal with the nozzles broke, allowing water to enter and chloride to concentrate. The water source is the fire protection sprinkler system (50-ppm chloride), which deluged the vessel eight to ten times in six years. Up to 60 000-ppm chloride was detected on the fracture face and, significantly, no bromide. Tests showed that the mastic contained 363-ppm leachable chloride and 36 300-ppm leachable bromide. The remedy was to terminate insulation with a metal cover and seal the gap between cover and nozzles with caulking compound.
Designing to Prevent Corrosion of Metals Under Insulation
Authors: Mettam CT
Published: December 2008

The paper concentrates on the corrosion of carbon steel under insulation. Austenitic steel corrosion is also mentioned. Hot and cold insulation materials are discussed with the main consideration place on “cold” problems. The current solution of the problem is to paint all carbon steel that is to be insulated and operating between -1 and 121°C. Insulation material and thickness is then selected. A moisture barrier or a vapor barrier is added to protect the insulation. Additional deterents added are vapor stops and contraction/expansion joints. A European versus an American design is examined as a conclusion. An Appendix, including protective coatings used, and drawings for additional clarification are included.
Use Inspection as a Means of Reducing Failures Caused By Corrosion Under Wet Insulation
Authors: Moak HA
Published: December 2008

This paper is an overview of what to look for in inspection to prevent the problem of corrosion under wet insulation. To assure quality, do not limit inspection of thermal insulation systems to just the installation. Review the work of the designer as critically as you do that of the installer. An excellent physical installation cannot always cure a poor design. Inspect on a routine basis to look for “tell-tale” signs of pending failures and follow up with prompt repair.
A New Apparatus and Test Procedure for Running ASTM C 692 Stress Corrosion Cracking Tests
Authors: Hutto FB , Tissot RG , Whitaker TE
Published: December 2008

A new experimental technique has been developed for running stress corrosion cracking tests on insulating materials. The new technique uses a steam heated pipe for heating the coupons and uses an “upside down” dripping action rather than a “wicking” action, as in ASTM Evaluating the Influence of Wicking-Type Thermal Insulations on the Stress Corrosion Cracking Tendency of Austenitic Stainless Steel (C 692). In addition to providing a more realistic approach, the new procedure correlates well with the old, simplifies sample coupon preparation and gives added reliability to the test results.
Comparisons of Several Accelerated Corrosiveness Test Methods for Thermal Insulating Materials
Authors: Sheppard KG , Patel S , Taneja M , Weil R
Published: December 2008

A study was conducted to provide data on which to base a corrosiveness test for the thermal insulating materials used in residential structures. Several possible test methods were compared. The materials tested included celluloses containing several different fire-retardant additives, glass fiber, rock wool, and a urea formaldehyde foam. Because of their widely differing physical properties, testing was conducted in water leachants made from the insulations. In addition, a test was performed that simulated the condensation conditions that might occur in a residence. It was found that two leachant-based methods could be suitable for accelerated corrosiveness testing of thermal insulation. One method involved determining the corrosion rate of metal coupons immersed in leachant for 14 days at 45°C. The other test was cyclic potentiodynamic voltammetry, which can be completed in only a few hours.
Fracture Mechanics: Fifteenth Symposium
Authors: Sanford RJ
Published: December 2008

Description

Subjects covered fall into several categories: theoretical, numerical, and experimental aspects of the mechanics of fracture; high-cycle fatigue; material influences on fracture; and elasto-plastic fracture mechanics.
Ecological Assessment of Macrophyton: Collection, USE, and Meaning of Data
Authors: Dennis WM , Isom BG
Published: December 2008

Description

Establishes a baseline of compilation of currently used methods to sample population of aquatic macrophytes. Discusses: designing sampling programs; Statistical problems; Mechanical sampling devices; and aerial photography.
Statistics in the Environmental Sciences
Authors: Gertz SM , London MD
Published: December 2008

Description

Discusses the development and application of mathematical and statistical techniques to environmental problems. Emphasis is placed on the conceptual framework of applying statistical analyses, but not at the expense of mathematical rigor. Rather, papers focus on the types of analyses available their usefulness under a variety of conditions, and the decision making process an investigator must go through prior to applying techniques.
Liquid Particle Size Measurement Techniques
Authors: Tishkoff JM , Ingebo RD , Kennedy JB
Published: December 2008

Description

Twelve papers review techniques for determining the drop size of sprays under various conditions and applications. The techniques include light scattering, resonance light scattering, laser-video imaging, drops on glass plates, and drop interaction with a hot wire.
Corrosion and Degradation of Implant Materials: Second Symposium
Authors: Fraker AC , Griffin CD
Published: December 2008

Description

An update of STP 684. Details new studies in vitro and in vivo of metals, polymers, and ceramic materials used in surgical implants. Subjects include aneurysm clip materials, fatigue ball-joint rods, electrochemical studies of dental alloys, arc plasma sprayed coatings, biocompatibility, biodegradation, risk management, performance standards, regulation, and litigation.
Inhalation Toxicology of Air Pollution: Clinical Research Considerations
Authors: Frank R , O'Neil JJ , Utell MJ , Hackney JD , Van Ryzin J , Brubaker PE
Published: December 2008

Description

Discusses issues critical to the design, execution, and analysis of basic and applied research. Divided into four sections: an overview of clinical research; measuring the response; subjects with underlying lung disease; and statistical and analytical considerations.
Hydraulic Barriers in Soil and Rock
Authors: Johnson AI , Frobel RK , Cavalli NJ , Pettersson CB
Published: December 2008

Description

Discusses permeability test methods used to evaluate hydraulic barriers, presents test results, and describes the effects of organic and inorganic permeants on slurry walls and clay and soil-admix liners.
Automated Test Methods for Fracture and Fatigue Crack Growth
Authors: Cullen WH
Published: December 2008

Description

Researchers describe their techniques for using automated systems to conduct fracture and fatigue tests. They discuss how they qualify their systems to assure that the data conform to existing ASTM standard tests.
Strength Testing of Marine Sediments: Laboratory and In-Situ Measurements
Authors: Chaney RC , Demars KR
Published: December 2008

Description

Provides a unifying state-of-the-art review of marine sediment strength testing. Identifies the types and varieties of in-situ and laboratory strength tests. Determines the environmental handling and preparation factors that affect strength measurements.
Aquatic Toxicology and Hazard Assessment: Eighth Symposium
Authors: Bahner RC , Hansen DJ
Published: December 2008

Description

Begins with papers establishing the need for RSP alloy development for use in aerospace and land vehicles. Follows with tutorial papers on solidification theory and stereological characteristics. Concludes with papers on powders, consolidations and processing, and characterization and properties.
Skiing Trauma and Safety: Sixth International Symposium
Authors: Mote CD , Johnson RJ
Published: December 2008

Description

Papers explain the factors resulting in ski injuries and the steps being taken to reduce the risk of ski injuries. Topics include: biomechanics and knee injuries; ski boots; release bindings, including testing; epidemiology of skiing injuries in Japan and Germany; spinal injuries; use of helicopter evacuation; and FIS efforts to control competitive skiing injuries.