bluuebunny/crossref_metadata_2025 huggingface dataset:
The Influence of Residual Copper in Annealed and Postweld Heat Treated 2-1/4Cr-1Mo Steel
Authors: Bodnar RL , Bramfitt BL , Cappellini RF
Published: December 2008

Vacuum arc remelted (VAR) and electroslag remelted (ESR) 2-1/4Cr-1Mo tube-sheet forgings were produced for the steam generators of the now terminated Clinch River breeder reactor project. The forgings were produced to American Society of Mechanical Engineers (ASME) SA336 Grade F22a, and test metal in the annealed and simulated postweld heat treated (PWHT) condition had to meet the minimum yield strength requirement of 207 MPa. All of the VAR forgings passed the yield strength requirement, while all of the ESR forgings marginally failed the yield strength requirement. The main difference between the two steels was the lower copper content of the ESR forgings (for example, 0.046 versus 0.13%). The yield strength increment in the annealed condition was accounted for by solid-solution strengthening due to copper, whereas in the PWHT condition, precipitation strengthening due to ϵ-copper accounted for the difference. This additional strengthening increment would have been sufficient to ensure that all of the ESR forgings met the minimum yield strength requirement. Both strengthening increments were confirmed with laboratory-produced and heat treated 2-1/4Cr-1Mo steels with copper levels of 0, 0.16, and 0.32%, and were found to be compatible with the most recent iron-copper phase equilibria. Yield strength was also found to increase by increasing the cooling rate from the PWHT. This strengthening increment is attributed to solid-solution strengthening due to carbon, nitrogen, molybdenum, and chromium, and precipitation strengthening due to (M2X) carbides. The data presented in this paper provide an example of residual copper affecting the mechanical properties of a 2-1/4Cr-1Mo steel. Furthermore, much of the data base used to establish the mechanical property capabilities of 2-1/4Cr-1Mo steel was developed using steels that had relatively high copper levels (or were not analyzed for copper), and were air-cooled from the PWHT, thus producing a data base of yield strength values that are higher than can be achieved under the constraints of the specification.
The Effect of Processing on Autohesive Strength Development in Thermoplastic Resins and Composites
Authors: Howes JC , Loos AC , Hinkley JA
Published: December 2008

The effects of processing on autohesive bond strength development in polysulfone resin and graphite-polysulfone composites were investigated. Autohesive bond strength development in polysulfone resin was observed by measuring the refracture toughness of precracked compact tension specimens that were healed at a given temperature and contact time. The fractured specimens, when completely healed, achieved the original toughness of the virgin resin. Results of the compact tension (CT) tests, when corrected for nonisothermal effects, compared favorably with diffusion models explaining crack healing and welding of amorphous polymers. Interply strength development in graphite-polysulfone unidirectional composites was measured as a function of healing temperature and contact time using a double cantilever beam (DCB) interlaminar fracture toughness test. The critical strain energy release rate of the refractured composites did not show a strong time or temperature dependence as observed in the neat resin tests. Furthermore, only 80 to 90% of the undamaged fracture energy can be recovered. The fracture mechanisms were determined to be different in the healed DCB specimen from those in the virgin specimen due to resin flow at the crack plane upon healing.
Stress-State Effects on the Viscoelastic Response of Polyphenylene Sulfide (PPS) Based Thermoplastic Composites
Authors: Myers FA
Published: December 2008

The viscoelastic properties of polyphenylene sulfide resin based carbon fiber-reinforced composites have been examined using torsion, centrosymmetric disk (CSD), and three-point and four-point flexure testing modes. Laminates fabricated with carbon fabric and a quasi-isotropic layup of continuous carbon fiber have been considered. Dynamic mechanical tests have shown that these materials exhibit a glass transition interval (Tg) from 50 to 150°C and a melting transition near 280°C. The storage component of the modulus or stiffness decreases from room temperature to 175°C by an amount which varies with the imposed stress or strain state. Fiber-dominated modes (three-point and four-point flexure) exhibit a smaller percentage loss in modulus or stiffness than resin-dominated modes (torsion and CSD). Arrhenius plots obtained from frequency sweep data in the glass transition region indicate the fabric-reinforced material and quasi-isotropic layup have activation energies of 130 and 105 kcal, respectively, independent of testing mode. Superposition of frequency/temperature or time/temperature data was achieved in dynamic mechanical and transient (that is, creep and relaxation) tests, respectively. Projection of the ten-year modulus, stiffness, or compliance from transient tests suggests that the response is stress-state dependent with greater change observed for resin-dominated testing modes.
Combustion of 316 Stainless Steel in High-Pressure Gaseous Oxygen
Authors: Benz F , Steinberg TA , Janoff D
Published: December 2008

The design of high pressure oxygen systems requires a better understanding of the combustion properties of structural metals and aIloys to make proper choices for any particular set of operating conditions. Upward combustion of 316 stainless steel (SS) rods is discussed and a combustion model is presented. The effects of varying oxygen pressure and rod diameter on the rate limiting processes for combustion of 316 SS are evaluated. The rate limiting steps for combustion up 316 SS rods are shown to be dependent on incorporation and mass transport of oxygen in the molten mass, and heat transfer between the molten mass and rod. Both these rate limiting steps are shown to be dependent on rod diameter. Small (dr = 0.051 cm) 316 SS rods are shown to be dependent on convective heat transfer and larger rods (dr ⩾ 0.32 cm) are shown to be dependent on oxygen incorporation and mass transport in the molten mass.
Design of an Ignition-Resistant, High-Pressure, High-Temperature Oxygen Valve
Authors: Christianson RC , Plante BA
Published: December 2008

Components used in high-pressure, high-temperature, flowing oxygen can be susceptible to ignition and combustion when particles travelling with the gas stream impact surfaces. Such impact was responsible for the violent combustion of the original Space Shuttle Main Propulsion System oxygen flow control valves during qualification testing at the NASA White Sands Test Facility. This provided the impetus to develop a new valve based on Shuttle operating specifications and on several criteria ensuring ignition resistance, proper performance, and fabrication economy. Several flow control devices and concepts were investigated, and the design incorporating a variable segmented orifice was considered most likely to meet the basic design parameters. This design was selected for further development, which resulted in a valve that met all established design parameters when tested under normal and worst-case conditions. These results confirm the position taken at the NASA White Sands Test Facility that components can be designed and fabricated to resist combustion caused by particle impact. Thus, adherence to general design parameters such as careful design of the gas flow path, appropriate selection of ignition-resistant materials, and configurational testing at worst-case operating conditions can ensure safe and reliable oxygen components.
Urinary Excretion Levels of Metal Ions in Patients Undergoing Total Hip Replacement with a Porous-Coated Prosthesis: Preliminary Results
Authors: Jones LC , Hungerford DS , Kenna RV , Braem G , Grant V
Published: December 2008

Porous-coated prostheses implanted without bone cement are currently being evaluated for use in patients undergoing total joint replacement (TJR). One parameter under study is the potential release of metal ions from these prostheses. In order to determine if there is a systemic increase in cobalt, chromium, or nickel levels within the body subsequent to total joint replacement with a porous-coated prosthesis, 24-h urine specimens were collected from patients prior to and subsequent to TJR with a PCA total hip prosthesis. Metal ion analysis was achieved using flameless atomic absorption spectroscopy. Increases in urinary cobalt and nickel excretion were detected in several patients at six months and in most patients at one year after surgery. However, these differences were not statistically significant. No differences between the preoperative and postoperative time periods (one week, six months, and twelve months) were detected for urinary levels of chromium. Although the metal ion levels for all of the patients studied appear to be in the range handled by the body's systemic compensatory mechanisms, which adjust levels of trace elements, continued follow-up is needed to determine the patterns and the long-term significance of metal ion release.
Clinical Indicators of Dental Implant Performance
Authors: Young FA , Montes GM
Published: December 2008

The traditional clinical indicators of implant performance are mobility, pocket depth, keratinized tissue width, amount of bleeding, amount of plaque accumulation, and gingival appearance.

This report examines measurements of these variables at intervals of 1 to 2 months for 36 months for 27 implants in 11 rhesus monkeys. The implants were cylindrical porous-rooted titanium alloy and were placed in premolar and molar mandibular sites using a two-stage technique. The implants were used to support both single-unit and multiple-unit restorations. Examination of traditional plots of indicator values versus time revealed no readily observable trends either for individual implants or for pooled implant data. The assumption was made that each observation may be expressed in terms of the additive relationship between the mean response of the total group of responses for an individual, the effect of time, and the error associated with the measurements. The data were analyzed using a multivariate analysis of variance with a repeated measures design (MANOVA, SPSS Inc., Chicago, Illinois). The analysis provided a control on differences between individuals because the effect of time was measured relative to the average response of the individual.

The conclusions of this study are (1) that the technique applied can be useful in determining trends in the measured indicators and (2) that a difference can be observed between implants supporting single-unit restorations and those supporting multiple-unit restorations.
Effect of Press Fit on Lateral Stem Stresses and the Integrity of Porous-Coated Femoral Prostheses: An In Vitro Strain Gage Study
Authors: Davidson JA , Bushelow M , Gavens AJ , DeMane MF
Published: December 2008

A strain gage analysis was performed to determine the stresses generated on the lateral surface of two types of porous-coated femoral prostheses. One type of prosthesis was made of wrought titanium (Ti-6Al-4V) alloy with a porous polysulfone coating; the other was a porous-coated alloy meeting the requirements of the ASTM Specification for Cast Cobalt-Chromium-Molybdenum Alloy for Surgical Implant Applications (F 75–82). Various degrees of fit were evaluated, ranging from a loose fit to one in which the stem was cemented into the femoral canal. The results showed that modeling pressfit porous-coated stems using cemented conditions can produce peak stresses on the lateral surface of the stem significantly lower than those for noncemented stems. Based on the fatigue strength of the stem material, the authors show that assessing stem integrity with the assumption that the cemented stem represents a complete bone ingrowth condition may lead to a design evaluation of the femoral stem that is overoptimistic for in vivo fatigue load conditions.
Flexible Porous Titanium for Revision Surgery: Concept and Initial Data
Authors: Ducheyne P , Cuckler JM
Published: December 2008

Bone stock deficiency is a major challenge encountered in the revision of failed hip arthroplasties. Loosening of the prosthetic components under aseptic conditions results in the loss of trabecular and cortical bone. At revision the surgeon is frequently faced with a thin smooth cortical tube with an almost complete absence of endosteal trabecular bone. Consequently, fixation of the revision component is seriously compromised. The objective of the present paper is to address this issue specifically by discussing a new concept in materials created to alleviate this major problem of deficient bone stock. The authors propose using a porous flexible titanium material to fill void spaces in the deficient bone structure. The material can easily be shaped at the time of surgery and has a pore size in the optimum range for bone ingrowth (100 to 600 µm). In addition, it is possible to infiltrate it with bone cement. Furthermore, the elastic properties of this material closely correspond to those of trabecular bone.

The objective in the design of this new material was to improve the current practice of revision surgery in three problem areas: first, by avoiding brittle fracture due to excess cement thickness; second, by decreasing the risk of disuse atrophy caused by large prosthesis stem sizes; and third, by filling the excess cavity with a material with elastic properties matching those of the missing tissue.
Biomechanical and Morphometric Testing Methods for Porous and Surface-Reactive Biomaterials
Authors: Gross U , Roggendorf W , Schmitz H-J , Strunz V
Published: December 2008

Two implantation sites were evaluated in the rabbit for measurement of the tensile strength of bonding between bone and both surface-reactive and metallic biomaterials. In rabbits, the tensile strength of bonding was 2.4 N/mm2 for glass-ceramic KG Cera rectangular solid implants that had been firmly clamped against cortical bone of the femur midshaft with champy plates for 56 days. The tensile strength of bonding was consistently less with cylindrical implants (flattened on one side) of the same material held against cortical bone of the femur midshaft with sutures or embedded into trabecular bone of the distal rabbit femur. The surface roughness of surface-reactive biomaterials affected the tensile strength of bonding only insignificantly.
A Method for Quantitative Characterization of Porous Biomaterials Using Automated Image Analysis
Authors: Shors EC , White EW , Edwards RM
Published: December 2008

An automated image analysis method is described for the quantitative characterization of porous biomaterials. The method consists of impregnating porous materials with epoxy embedding medium and polishing planar sections. Contrast was optimized under a scanning electron microscope using backscattered electron images or under a light microscope using reflected light. The images were analyzed using an image analysis system and software developed for this study. The parameters measured on each image feature of the solid and void fractions, frame by frame, were the area fraction, internal perimeter, minimum crossing distance, number of features per area, equivalent circular diameter, perimeter squared per area, and distribution of equivalent circular diameter squared.

The usefulness of this method was validated by comparing the median values of these parameters and their statistical distributions on Replamineform porous biomaterials derived from echinoid and coral skeletons. We believe that this method for quantitative characterization of the three-dimensional structure of biomaterials is applicable to a broad range of materials and is readily amenable to standardization.
Comparison of Porous and Nonporous hydroxyapatite and Anorganic Xenografts in the Restoration of Alveolar Ridges
Authors: Boyne PJ
Published: December 2008

This paper reports the results of surgical investigation of three types of hydroxyapatite implanted in ten adult Macaca fascicularis monkeys. The hydroxyapatite was placed in edentulous alveolar ridges of the animals. Three types of implants were evaluated—porous hydroxyapatite, nonporous granular hydroxyapatite, and xenografts of bovine bone. The results indicated that all three implants increased the thickness and height of the alveolar ridge. The anorganic xenogeneic bone was more effective in being replaced by host bone than either the porous or nonporous hydroxyapatite. Bony ingrowth into the hydroxyapatite in the porous implants was more extensive than bony growth around nonporous particles.
Studies on a Porous Alumina Dental Implant Reinforced with Single-Crystal Alumina: Animal Experiments and Human Clinical Applications
Authors: Yamagami A , Kotera S , Kawahara H
Published: December 2008

A new type of porous alumina dental implant has been designed. A biological seal is provided by single-crystal alumina on its cervical portion, and fixation capability in bone is provided by a porous alumina layer with an average interconnecting pore size of approximately 130 μm.

The mandibular premolar and molar extraction sites of 15 male rhesus monkeys (3 to 6 years old) were used in the animal experiments. All the implants and superstructures that were not retained by attachment to proximate teeth participated in functional occlusion at all times except during the first two to four weeks.

After four, six, and eight months, histological examinations, including light microscopy (LM), scanning electron microscopy (SEM), and electron probe microanalysis (EPM), were conducted. The surrounding gingival tissue strongly adhered to the single-crystal alumina on the cervical portion of the implant, and prolific bone ingrowth was observed within the porous network of the root component.

The human clinical evaluations showed a high success rate of 94% in 45 cases. Long-term clinical cases were included, the longest implant having survived for eight years in free-standing form. These cases included 23 free-standing cases and 22 bridge cases; 3 of these failed in the first stage of human clinical trials.
A Method for Evaluating Methyl Bromide Fumigant Under Low-Temperature Conditions
Authors: Ashton AD , Delventhal K , Sargent J
Published: December 2008

Fumigants normally are not used at subfreezing temperatures, because of low efficacy for arthropod control. Rodents, being homeothermic, can be controlled readily during cold weather. However, data are not currently available to judge dosage and exposure variables. A chamber fumigant test procedure using methyl bromide is described, in which dosage and length of exposure can be controlled at ambient temperatures.
Towards a New Standard for Laboratory Accreditation Terminology
Authors: Unger PS
Published: December 2008

After years of discussion and several drafts, ASTM Committee E36 on Criteria for the Evaluation of Testing and Inspection Agencies established a new standard for terminology related to laboratory accreditation. Laboratory accreditation has been defined as a formal recognition that a testing laboratory is competent to carry out specific tests or specific types of tests. Twenty-seven other terms have been defined. Among the more difficult issues to resolve were the definitions for general criteria versus generic criteria and specific criteria, calibration versus standardization, laboratory assessment versus evaluation, and laboratory quality assurance and quality control. This paper discusses the formulation of the current definitions and some of the issues involved, identifies terms which have yet to be defined, and indicates a future course that the terminology subcommittee may take.
The NAMAS Accreditation System
Authors: Summerfield JD
Published: December 2008

The National Measurement Accreditation Service (NAMAS) is the United Kingdom (UK) national third party accreditation service for both calibration and testing laboratories. Based at the National Physical Laboratory (NPL), NAMAS is a government service which encourages industry to make improvements to every aspect of its quality procedures by providing formal traceability for all its measurements to the national primary standards held at NPL. NAMAS provides an essential link between government and industry and plays a leading role in the UK National Measurement System and the Government National Quality Campaign.
Laboratory Accreditation and Quality System Accreditation—A Merging of the Ways
Authors: Bell MR
Published: December 2008

Laboratory accreditation and quality system accreditation have been developing along parallel lines for some years but to date there has been little interaction between agencies undertaking the two functions. In New Zealand the Testing Laboratory Registration Council (TE-LARC) now undertakes both laboratory accreditation and quality system accreditation. This has allowed an integrated approach to be adopted focusing on quality assurance in the laboratory and the proper accreditation of quality control laboratories within industry.
Fracture Characteristics of Angleplied Laminates Fabricated from Overaged Graphite/Epoxy Prepreg
Authors: Ginty CA , Chamis CC
Published: December 2008

A series of angleplied graphite/epoxy laminates was fabricated from overaged prepreg and tested in tension to investigate the effects of overaged or “advanced-cure” material on the degradation of laminate strength. Results which include fracture stresses indicate a severe degradation in strength. In addition, the fracture surfaces and microstructural characteristics are distinctly unlike any features observed in previous tests of this prepreg and laminate configuration. Photographs of the surface and microstructures reveal flat morphologies consisting of alternate rows of fibers and hackles. These fracture surface characteristics are independent of the laminate configurations. The photomicrographs are presented and compared with data from similar studies to show the unique characteristics produced by the overaged prepreg. Analytical studies produced results which agreed with those from the experimental investigations.
Fracture Morphology of 13% Chromium Steam Turbine Blading Steel
Authors: Bhambri SK
Published: December 2008

To understand micromechanisms of steam turbine blade failures, a variety of fracture morphology was generated in 13Cr-Mo-V steel by controlled laboratory tests. The primary variables were microstructural condition and environment. Micromechanisms operative during fracture under impact and fatigue loading have been presented and discussed.
Micromechanisms of Major/Minor Cycle Fatigue Crack Growth in Inconel 718
Authors: Venkataraman S , Nicholas T , Ashbaugh NE
Published: December 2008

Fatigue crack growth tests under major/minor cycle loading were conducted on Inconel 718 at 649°C using center-cracked tension specimens, M(T). The loading waveform used consisted of a major cycle loading (1 Hz) and a hold at the major cycle maximum load, with a superimposed minor cycle loading (10 Hz) during the hold period. Crack growth data were obtained for a range of major and minor cycle stress intensities. Constant load amplitude tests were also run at various R-values to determine the effect of R on major/minor cycle fatigue. Detailed fractographic investigation was conducted on selected specimens using a scanning electron microscope to study the associated micromechanisms. Creep processes as indicated by an intergranular fracture mode were found to be dominant at lower minor cycle stress intensity ranges and higher values of R for the minor load. Transition to fatigue-dominant mechanisms as indicated by a transgranular fracture mode occurred at higher stress intensity ranges and lower R-values for the minor load. The minor cycle stress intensity range at which this transition occurred varied with the major cycle stress intensity range.
Cessation of Irradiation Creep in AISI 316 Concurrent with High Levels of Swelling
Authors: Porter DL , Garner FA
Published: December 2008

At high neutron exposures where the swelling of AISI 316 exceeds ∼5% the irradiation creep rate at 550°C begins to decline and eventually disappear. Swelling continues to proceed, however, leading to a maximum deformation rate dictated only by that of the steady-state swelling rate or ∼0.33%/displacements per atom (dpa). It is not clear at this point whether large levels of voidage are directly responsible for the decrease in creep rate. There is some evidence to support the possible role of intermetallic precipitate formation, although the mechanism of creep suppression by such precipitates is not known.
Post-Irradiation Fracture Properties of Precipitation-Strengthened Alloy D21
Authors: Huang F-H
Published: December 2008

The precipitation strengthened alloys have the potential for use in fuel cladding and duct applications for liquid metal reactors due to their high strength and low swelling rate. Unfortunately, these high strength alloys tend to exhibit poor fracture toughness, and the effects of neutron irradiation on the fracture properties of the material are of concern. Compact tension specimens of alloy D21 were irradiated in the Experimental Breeder Reactor II to a fluence of 2.7 × 1022 neutrons (n)/cm2 (E > 0.1 MeV) at 425, 500, 550, and 600°C. Fracture toughness tests on these specimens were performed using electric potential techniques at temperatures ranging from 205 to 425°C. The material exhibited low post-irradiation fracture toughness which increased with either increasing test or irradiation temperature. The tearing modulus, however, increased with increasing irradiation temperature but decreased with increasing test temperature. Results were analyzed using the J-integral approach. The fracture toughness of irradiated D21 was evaluated essentially following the procedure recommended in ASTM Test Method E813. It was found that the data elimination limits illustrated in E813 were too large for the specimens tested, although the thickness criterion was satisfied. The precautions needed to determine JIc based on a reduced data qualification range were discussed.
Mechanical Properties at Low and High Strain Rates of PE 16 Alloys Irradiated to 9.2 dpa
Authors: Albertini C , Del Grande A , Montagnani M , Pachera A
Published: December 2008

The mechanical properties of nimonic alloy PE 16 are reported, for the strain-rate range 10−3 to 103 s−1, at ambient temperature, 400 and 500°C, on as-received, thermally aged (9864 h in sodium at 500°C), and irradiated to 9.2 dpa materials. Regarding the irradiated material one observes: (1) the effect of irradiation consisted of a marked increase of flow stress ranging between 100 and 30% and a reduction of ductility of about 20% points with respect to the as-received material; (2) decrease of flow stress with increasing strain-rate of small value at ambient temperature while it reaches the value of about 15% at high temperature; (3) dynamic strain aging with serrations along the flow curves at high temperature and low strain-rate.

The decrease of the flow stress with increasing strain-rate of the irradiated material seems to be caused by (1) the dynamic strain aging that is present at low strain rate and not at high strain rate; (2) the thermal softening caused by the temperature rise during the adiabatic dynamic testing; and (3) the accentuation of the effects of the two preceeding phenomena caused by the damage introduced by irradiation.
Fatigue Crack Growth and Fracture Toughness Properties of Low Fluence Neutron-Irradiated Type 316 and Type 304 Stainless Steels
Authors: De Vries MI
Published: December 2008

Small compact-tension specimens of Type 316 plate and Type 304 forging have been irradiated in the High Flux Reactor (HFR) at Petten, The Netherlands, up to a fluence level of 2 × 1024 neutrons (n) · m−2 (E > 0.1 MeV) at 573 K. Post-irradiation fatigue crack propagation tests and J-integral fracture toughness tests have been performed at the irradiation temperature. Additional tests were made at the higher temperatures of 723 and 823 K.

The two materials exhibited almost identical crack growth curves after irradiation, despite the chemical and microstructural differences between the materials in the as-fabricated condition.

The irradiation caused a slight increase of the resistance to crack growth under cyclic and monotonic loading at 573 K. This is attributed to irradiation hardening from displacement damage, the latter being observed in the form of the well-known black dots. The additional tests showed modest degradation of the resistance at 723 and 823 K, but the fatigue crack growth resistance decreased significantly under low frequency loading at 823 K because of helium-enhanced intergranular crack formation.

The results are compared with fatigue and toughness curves for Type 304 and Type 316 plate and welds after similar irradiations in the HFR and in thermal material test reactors in the United Kingdom (UKMTR). The closely corresponding curves show the same type of results after the various irradiations.

It is concluded that low fluence (less than 1 dpa, displacements per atom) irradiations at temperatures below 700 K, have a slight beneficial effect on the crack growth resistance of austenitic stainless steels. Nevertheless, the fatigue crack growth rates of Type 316 plate and Type 304 forging are still higher than for weld metal, although the toughness properties are better than for weld metal.
Effect of Cold Work on Tensile Behavior of Irradiated Type 316 Stainless Steel
Authors: Klueh RL , Maziasz PJ
Published: December 2008

The effect of various levels of cold work on the tensile behavior of Type 316 stainless steel was investigated. Tensile specimens were irradiated in the Oak Ridge Research Reactor (ORR) at 250, 290, 450, and 500°C to produce a displacement damage of ∼5 displacements per atom (dpa) and 40 atomic ppm He. Irradiation at 250 and 290°C caused an increase in yield stress and ultimate tensile strength and a decrease in ductility relative to unaged and thermally aged controls. The changes were greatest for the 20%-cold-worked steel and lowest for the 50%-cold-worked steel. Irradiation at 450°C caused a slight decrease in strength for all cold-worked conditions relative to the aged material. A large decrease was observed at 500°C, with the largest decrease occurring for the 50%-cold-worked specimen. No bubble, void, or precipitate formation was observed for specimens examined by transmission electron microscopy (TEM). The irradiation hardening was correlated with Frank-loop and “black-dot” damage. A strength decrease at 500°C was correlated with dislocation network recovery. Comparison of tensile and TEM results from ORR-irradiated steel with those from steels irradiated in the High Flux Isotope Reactor and the Experimental Breeder Reactor indicated consistent strength and microstructure changes.
Radiation Effects on the Micromechanics of Fatigue Crack Initiation
Authors: Naughton TD , Ghoniem NM , Lin TH
Published: December 2008

A micromechanical model is employed to investigate parameters that affect the rate of local plastic strain in and around persistent slip bands in cyclically loaded metals. The model utilizes a solution of the stress field in a semi-infinite elastic-plastic medium under generalized plane deformation. By following the evolution of the stress field, a natural gating mechanism is observed to produce regions of localized deformation. The regions of local deformation develop into extrusions and intrusions that are responsible for the formation of fatigue cracks.

By coupling this micromechanical model with an empirical correlation developed to predict the increase in critical shear stress as a function of fluence and temperature, an investigation of radiation effects on fatigue crack initiation is carried out. It is determined that longer fusion reactor burn times and lower operating temperatures inhibit the crack initiation rate. Because of irradiation induced-hardening, increases in the fatigue limit are predicted for long reactor burn times (>103 s) and low operating temperatures (<300°C). Irradiation is found to increase the number of cycles required to obtain a failure strain at low temperatures and high-cycle fatigue conditions.
The Effects of Temperature and Strain Rate on the Properties of (Fe,Ni)3V LRO Alloys
Authors: Lin HT , Wilcox RC , Chin BA
Published: December 2008

Tension tests with two distinctly different strain rates, 2.8 × 10−5 and 2.8 × 100 s−1, have been performed on the (Fe,Ni)3V long-range ordered (LRO) alloys in aged and unaged condition between 20 and 750°C. Tensile results as a function of test temperature indicate that the LRO alloys have good high-temperature strength. The yield strength of the ordered alloys increases with increasing test temperature, rather than decreasing as in conventional alloys. Long-term aging at 600°C has little or no effect on the elevated temperature tensile properties, and tends to reduce the sensitivity of aged materials to strain rate. The deformation mechanisms are changing as a function of test temperature, while there is a minor change in fracture characteristics over test temperature range. Oxidation features show the iron-base LRO alloys have limited oxidation resistance above 600°C.
Tensile Properties of Irradiated Pressure Vessel Steels
Authors: Lucas GE , Robert Odette G , Maiti R , Sheckherd JW
Published: December 2008

Yield stress and hardness changes have been demonstrated to be strongly correlated to transition temperature shifts in nuclear pressure vessel steels, and hence such measurements can be a convenient means for evaluating the role of metallurgical and environmental variables in embrittlement. We have irradiated miniature tensile specimens of over 100 alloy (chemistry and thermomechanical treatment) variants at nominal fluxes 0.5 to 5 × 1016 n/m2·s, temperatures 271 to 325°C, and fluences 0.15 to 3 × 1023 n/m2. A subset of these specimens has been tested, and the results are reported here. For both commercial and model alloys, good agreement between hardness and yield stress changes were observed. Yield stress changes were strongly influenced by copper and nickel content and by thermomechanical treatment.
A Comparison Between French Surveillance Program Results and Predictions of Irradiation Embrittlement
Authors: Brillaud C , Hedin F , Houssin B
Published: December 2008

At the beginning of 1986, thirty-two 900-MWe and four 1300-MWe nuclear power stations were in service in France. A regulatory surveillance program is in progress concerning the base metal, weld metal, and heat affected zones of every nuclear pressure vessel; a reference metal sample is also present in each reactor. This surveillance program was implemented largely in accordance with U.S. rules. The specifications for the core shell forgings in MnNiMo low alloy steel and the associated welds require low contents in embrittling elements such as copper and phosphorus. The results presented here concern materials containing less than 0.08 wt% Cu and 0.011 wt% P, except for the welds of the first six reactor vessels, which have 0.13 wt% Cu and 0.019 wt% P maximum. The main aim is to obtain the RTNDT shift from Charpy-V tests, in relation to the fluence measured from fissile and activation dosimeters. Tensile, compact, and three-point bend specimens are also included in the capsules.

Results for the first capsules removed after up to four years of operation, corresponding to fluences (E > 1 MeV) less than 1.5 × 1019 n · cm−2 (2.9 × 10−2 dpa), are presented and evaluated. The mean and upper values of the RTNDT shift are about 20 and 40°C, respectively, and there is no significant difference between parent metal and weld. A new formula to predict embrittlement has been derived from test reactor experiments, because of the strict limits on the residual element contents in French materials when compared with materials for which other formulae have been established. The surveillance program results are discussed and compared with the predictions of these formulae.
Irradiation Embrittlement Evaluation Without Lateral Expansion Measurements
Authors: Chatterjee S , Anantharaman S , Sivaramakrishnan KS , Roy PR
Published: December 2008

It is progressively felt that the lateral expansion criterion should be included for the determination of the transition temperature for irradiation embrittlement studies as this criterion compensates for the effects of irradiation induced increases in the strength. Lateral expansion measurements on irradiated specimens require specially designed jigs and time consuming remote measurements to be made inside a shielded cell. Results generated on eighth A533 and A508 category of pressure vessel steels and weldments containing copper contents up to 0.125 wt%, phosphorous contents up to 0.015 wt%, and subjected to fast neutron fluences (>1 MeV) of the order of 1 × 1019 n/cm2 at 290°C were analyzed to find out whether fixed energy criterion alone could be used instead of lateral expansion criterion. The adjusted reference temperature RTNDT of these irradiated steels and weldments, as obtained from the unirradiated reference temperature RTNDT according to the American Society of Mechanical Engineers (ASME) Code, Section III, and the temperature shift at 41J absorbed energy (ΔT41J), were compared with the reference temperature RTNDT of the irradiated steels and weldments as obtained directly as per ASME Code, Section III. It was observed that in practically all these materials, the latter values were conservative. It was found that for these steels and weldments, if 68J absorbed energy criterion is used, no lateral expansion measurements need to be carried out.
Trend Curve Data Development and Testing
Authors: McElroy WN , Gold R , Simons RL , Roberts JH
Published: December 2008

Existing trend curves do not account for previous and more recently observed test and power reactor flux-level, thermal neutron and γ-ray field-induced effects. Any agreement between measured data and trend curve predictions that does not adequately represent the important neutron environmental and temperature effects as well as the microstructural damage processes, therefore, could be fortuitous. Empirically derived end-of-life (EOL) and life-extension-range (LER) trend curves are presented and discussed in this paper for high temperature [∼288°C (550°F)] irradiation of two weld, two plate, and two forging pressure vessel (PV) steels and low-temperature [∼60°C (140°F)] irradiation of one support structure-type steel.

Preliminary results of a comprehensive study of the effects of environmental variables (neutron spectrum, exposure, exposure rate, and the thermal and γ-ray fluxes associated with surveillance capsules and PV through-wall gradients) were used to develop these trend curves.

Pressurized water reactor (PWR) and boiling water reactor (BWR) plant-specific results together with those of the Poolside Facility (PSF) of the Oak Ridge Research Reactor (ORR) at the Oak Ridge National Laboratory (ORNL) and other research reactor experiments support the existence of a significant material-dependent flux-level effect for PV and support structure steels; that is, a steel may show a decrease, an increase, or no change in the measured Charpy shift with changes in fluxlevel. Further, the actual behavior of a material can change significantly as a function of neutron exposure; also, thermal neutron and γ-ray effects can contribute to observed changes in property, especially near steel-water interface positions with high thermal-to-fast-neutron ratios.
Effect of Gamma Radiation on the Permeability of Opthalmic Preservatives Through Fluorine Surface-Treated Low-Density Polyethylene Bottles
Authors: Sparacio DA , Amini MA
Published: December 2008

Efforts to improve the barrier properties of polyethylene have led to the development of fluorine surface treatments in which the surface of polyethylene is changed from nonpolar to polar by replacing some of the hydrogen atoms in the polyethylene chains with fluorine atoms. The purpose of this study was to determine the effect of gamma radiation on the permeability of benzyl alcohol, phenylethyl alcohol, and 3-phenyl-1-propanol through fluorine treated and untreated 15-cm3 Boston round bottles, which were injection blow molded from low-density polyethylene (LDPE). Using a weight loss technique, it was concluded that the fluorine treatment alone improved the barrier properties, especially at elevated temperatures. Irradiation of the bottles at the 5.0- and 7.5-Mrad level also improved their barrier properties; irradiation at the 2.5-Mrad level improved their barrier properties except for untreated bottles that were stored at 50°C. Results are analyzed based on the molecular structure of the LDPE with and without fluorine surface treatment.
Irradiation Facilities at the Idaho National Engineering Laboratory
Authors: Gupta VP , Herring JS , Korenke RE , Harker YD
Published: December 2008

Although there is a growing need for neutron and gamma irradiations by governmental and industrial organizations in the United States and in other countries the number of facilities providing such irradiations are limited. At the Idaho National Engineering Laboratory, there are several unique irradiation facilities producing high neutron and gamma radiation environments. These facilities could be readily used for nuclear research, materials testing, radiation hardening studies on electronic components/circuitry and sensors, and production of neutron transmutation doped (NTD) silicon and special radioisotopes. In addition, a neutron radiography unit, suitable for examining irradiated materials and assemblies, is also available. This paper provides a description of the irradiation facilities and the neutron radiography unit as well as examples of their unique applications.
Improvement of Accuracy Assessment in Radiation Damage Predictions
Authors: Zijp WL , Zsolnay ÉM , Nolthenius HJ
Published: December 2008

This paper gives the first results of the interlaboratory exercise, REAL-84. The exercise has as its aim the improvement of the assessment of the accuracy in predictions of radiation damage in steel, in a calculation exercise in which the best available input data and the best available calculation methods are used. In this report the results of 39 solutions from 10 participants, which were received before Feb. 1986, are discussed.
Spectrum Integrated (n,He) Cross Section Comparison and Least Squares Analysis for 6Li and 10B in Benchmark Fields
Authors: Schenter RE , Oliver BM , Farrar H
Published: December 2008

Spectrum integrated cross sections for 6Li and 10B from five benchmark fast reactor neutron fields are compared with calculated values obtained using the ENDF/B-V Cross Section Files. The benchmark fields include the Coupled Fast Reactivity Measurements Facility (CFRMF) at the Idaho National Engineering Laboratory, the 10% Enriched U-235 Critical Assembly (BIG-10) at Los Alamos National Laboratory, the Sigma Sigma and Fission Cavity fields of the BR-1 reactor at CEN/SCK, and the Intermediate-Energy Standard Neutron Field (ISNF) at the National Bureau of Standards.

Results from least square analyses using the FERRET computer code to obtain adjusted cross section values and their uncertainties are presented. Input to these calculations include the above five benchmark data sets. These analyses indicate a need for revision in the ENDF/B-V files for the 10B cross section for energies above 50 keV.
Strategy for Industrial Hygiene Monitoring in the Chemical Industry
Authors: Norwood SK
Published: December 2008

The traditional approach to industrial hygiene sampling involves the subjective evaluation of factors in the work environment such as the likelihood of exposures during certain job tasks, the frequency of such tasks, the toxicity of the chemicals encountered, and the type of sampling needed to adequately quantify the particular exposures of interest. This approach to sampling requires judgment based on past experience and is most effective when there is adequate communication between industrial hygienists, physicians, toxicologists, analytical chemists, safety engineers, and process engineers. Recently, sampling strategies have incorporated statistical methods to aid in data interpretation and the selection of sample size. However, reliance on a statistical approach alone will not suffice to determine optimum sampling strategies because the objectives of industrial hygiene programs will usually extend beyond compliance to exposure guidelines. A sampling strategy should be founded on the traditional approach, but incorporate statistical methods where applicable. This balanced approach to sampling design offers a better utilization of industrial hygiene resources while accomplishing the objectives of the total industrial hygiene program.
Collection and Analysis of Airborne Hexamethylene Diisocyanate by a Modified OSHA Method
Authors: Podolak GE , Cassidy RA , Esposito GG , Kippenberger DJ
Published: December 2008

A modified Occupational Safety and Health Administration (OSHA) method for the determination of 1,6-hexamethylene diisocyanate (HDI) in air was tested in the laboratory and applied in the analysis of spray paint environments. Field tests included side-by-side comparison of alternative procedures of HDI sampling, along with tests to define the stability of 1-(2-pyridyl) piperazine [1-(2-P)P] impregnated filters, and the effect of increased reagent loading. Since the method employs 1-(2-P)P in excess to form the HDI-urea derivative that is then analyzed by high-performance liquid chromatography (HPLC), there is unreacted reagent present in samples. This residual (unreacted) portion causes HPLC interferences, extended analysis time, and deterioration of HPLC columns. To avoid these undesirable characteristics, a means for the removal of “excess” reagent was developed. This paper describes the application of a multi-port valve and short precolumns for facilitating the removal of “excess” reagent and presents data generated by this improved method.
ASTM and Semi Standards for the Semiconductor Industry
Authors: Scace RI
Published: December 2008

This article, based on an introductory talk at the symposium, points out the needs for standards in the semiconductor industry and briefly describes the activities of the organizations that develop them. The direct cooperation between the several organizations in the world active in semiconductor standards development is briefly described. Readers are invited to join these development activities.
Characterization of the in Situ HCl Etch for Epitaxial Silicon
Authors: Medernach JW , Wells VA
Published: December 2008

An experimental design strategy was used to characterize the in situ HCl etch used in the epitaxial silicon deposition and the selective epitaxial silicon processes. The dependence of the etch rate, haze and etch anisotropy is determined as a function of the HCl flow and etch temperature. Results show that temperatures less than 1025°C are the only limitation for the in situ HCl etch used in the epitaxial silicon process. Patterned oxide substrates which are used in a selective epi process show different etch rate and haze characteristics than unpatterned substrates. Etch anisotropy on the oxide patterned substrates limits the operational region for the selective epi process.
Doped Oxide Spin-On Source Diffusion
Authors: Ramamurthy V
Published: December 2008

The advantages offered by doped oxide spin-on source diffusion are briefly out-lined from thermodynamic as well as techno-economic considerations. Diffusion characteristics are presented for spin-on sources of gallium, gallium with boron, gallium with arsenic, boron and phosphorus, keeping in view their potential applications. Sheet resistivity and doping profile measurements show that the dopant distributions which essentially exhibit a time varying surface concentration, cannot be explained by any of the existing models for solid-state diffusion available in the literature. With three specific examples it is shown how this technique can be employed for the fabrication of different types of semi-conductor devices. The investigations also show that the results of diffusion are independent of gas-flow rates as this type of diffusion dispenses with gas-solid interactions.