bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radiation Damage Rate Measurements in Nickel
Authors: Schüle W 
Published: March 2009

Measurements of the electrical resistivity on almost dislocation free nickel specimens were performed during irradiation with 1.85 MeV electrons. Results obtained for irradiation temperatures varying between -80 and -40°C and for production rates varying between 2.10-11 and 5. 8 ∙ 10-10 dpas -1 are reported.
It was found that the electrical resistivity per Frenkel defect ρ, varies with the measuring temperature yielding a value of ρ = 2.33 ∙10 -4 Ωcm for TM = -60, 0°C.
Interstitials are not mobile for irradiation temperatures below Tirr = -60°C and quasi steady state defect concentrations are obtained in due time for irradiation temperatures higher than Tirr = -45°C. The results are compatible with the finding that the migration activation energy of interstitials decreases with increasing high energy particle flux i.e. from a value EIIM = 1.03 eV without irradiation to EIIM = 0.885 eV for a production rate of K = 3.46∙10 -10 dpas -1.
It was further found that di-interstitials are formed in situ when an existing interstitial encounters a dynamic crowdion. Di-interstitials are very mobile at an irradiation temperature of Tirr = -60°C initiating the formation of interstitial clusters which are enriched in undersized impurity atoms, e.g. in silicon.
In the presence of large interstitial clusters or precipitates the migration activation energy of interstitials decreases further e.g. a value of EIIM ≤ 0.82 eV is found for specimens irradiated for τirr = 2∙106 s.
Effects of Irradiation Temperature on Charpy and Tensile Properties of High-Copper, Low Upper-Shelf, Submerged-Arc Welds
Authors: Nanstad RK , Berggren RG 
Published: March 2009

The Heavy-Section Steel Irradiation Program conducted the Second and Third Irradiation Series to investigate the effects of irradiation on the ductile fracture toughness of seven commercially fabricated low upper-shelf welds. All seven submerged-arc welds were fabricated with copper-coated wire and Linde 80 flux and have average bulk copper contents ranging from 0.21 to 0.42% with nickel levels of about 0.6%. The preirradiation upper-shelf energies range from 74 to 111 J (55–82 ft-lb). Compact specimens up to 101.6 mm (4 in.) thick, 4TC(T), were irradiated at nominally 288°C in the Bulk Shielding Reactor at Oak Ridge National Laboratory to fluences ranging from about 4 to 12 × 1018 neutrons/cm2 (&gt;1 MeV). Charpy V-notch and tensile specimens were included in the capsules at available locations which were subject to wide variations in irradiation temperature and fluence.
This paper presents analyses of the Charpy impact and tensile test data, including adjustments for irradiation temperature and fluence normalization which make possible comparison of the irradiation sensitivity of the different welds. Analyses revealed a dependence of yield and ultimate strength on irradiation temperature of -1.1 and -0.8 MPa/°C, respectively. Similarly, the Charpy impact energy changes due to irradiation temperature were -0.5°C/°C for transition temperature shift and -0.05 J/°C for the upper-shelf energy decrease. After adjustment to an irradiation temperature of 288°C and normalization to a fluence of 8 × 1018 neutrons/cm2, percentage increases in yield strength due to irradiation ranged from about 21 to 35% while those for ultimate strength ranged from about 13 to 20%. The Charpy transition temperature shifts ranged from 59 to 123°C while the postirradiation upper-shelf energies ranged from 58 to 79 J.
Influence of Some Alloying Elements on the Formation of Vacancy Defects in Ferritic Steels During Irradiation at 288°C
Authors: Akamatsu M , Dai G , Li X , Moser P , Van Duysen JC , Zacharie G 
Published: March 2009

In order to determine if the formation of vacancy defects in pressure vessel steels during neutron irradiation is partly controlled by the chemical composition, we have studied the effects of electron irradiations on the following model alloys : Fe, Fe-0, l%Cu, Fe-0,l%Cu-0,004%C, Fe-0, l%Cu-0,010%C, Fe-0, l%Cu-0, 5%Mo, and Fe-0, l%Cu-l, 2%Mn. The irradiations have been carried out at 288°C and 150°C with fluences up to 4 1023 e-.m-2. After irradiation, some samples underwent 30 min annealing treatments at temperatures ranging up to 380°C.
The mobility of vacancies and their ability to form clusters have been studied by the positron annihilation technique. We have noticed that the clustering of single vacancies in iron is favoured by the presence of molybdenum or carbon. The observed defects are small and are made of 10 to 13 vacancies. In the same conditions, copper and manganese do not seem to have any effect on the formation of vacancy clusters. We have also observed that the recovery of the vacancy-type defects occurs at temperatures close to that of pressure vessel of PWR (288°C). These temperatures depend also on the nature of the alloying elements.
Influence of Cold Work, Heat Treatment, and Chromium Content on the Fracture Properties of Irradiated Martensitic Steels
Authors: Huang FH 
Published: March 2009

Martensitic steels undergo a change in the fracture mode from ductile microvoid coalescence to brittle cleavage as temperature decreases. Neutron exposure can raise the ductile-brittle transition temperature and produce a condition of low toughness during service. This study examines the effects of cold-work, heat treatment, and chromium content on the postirradiation fracture behavior of selected steels to provide a better understanding of fracture resistance in hopes of improving it.
Experimental materials included alloy HT9 containing 12 percent Cr, a vacuum remelt of HT9, modified HT9 containing 10 percent Cr, and 9Cr-1Mo. They were irradiated in the Experimental Breeder Reactor(EBR)-II at 400 to 550°C to fluences of 2.9 and 6 × 1022 n/cm2 (E &gt; 0.1 MeV). Results of fracture toughness tests conducted at temperatures from 93 to 450°C with electric-potential single-specimen techniques were analyzed by means of the J-integral approach.
The initiation fracture toughness of irradiated martensitic steels increased with increasing chromium content and tempering temperature. Remelting of HT9 slightly raised the fracture toughness of the irradiated materials. Cold work did not improve the fracture resistance of irradiated ferritic steels. Initiation fracture toughness decreased slightly while the tearing modulus increased significantly as irradiation temperature increased from 400°C to 500°C. Results also showed that neutron fluence had little effect on the fracture resistance of these steels, over the present range of fluences.
Mechanical Property Degradation of Fast Reactor Fuel Cladding During Thermal Transients
Authors: Shibahara I , Omori T , Sato Y , Onose S , Nomura S 
Published: March 2009

Temperature-transient-to-burst tests were performed on irradiated Type 316 stainless steel cladding. Special attention was paid to control the atmosphere for specimen preparation and testing to avoid possible change in the chemical state of the fission products which remained inside the fueled specimens. Under the controlled atmosphere, the burst temperature of the irradiated fueled cladding was not degraded at lower stress level by the ‘fuel adjacency effect (FAE)’. The so-called fuel adjacency effect was suspected to be caused, at least in part, by an atmospheric effect during post-irradiation examination.
The transient burst temperatures of Type 316 stainless steels were fairly insensitive to the material conditions in a controlled testing environment, although the onset of swelling acted to decrease the failure temperature. Results were also presented for irradiated advanced austenitic stainless steel and ferritic/martensitic steel cladding.
Effects of Applied Stress on Microstructural Evolution in 316SS Under Ion Irradiation
Authors: Katoh Y , Yutaka Y , Kohyama A 
Published: March 2009

To obtain fundamental knowledge about the stress effects on microstructural behavior in irradiated materials, we developed a tensile loading apparatus which is to be mounted on the dual-ion irradiation stage of the High-fluence Irradiation Facility of the University of Tokyo and established a corresponding experimental method. In the first part of this paper, a description of the facility and the experimental technique are given.
As an initial experiment using this facility, austenitic Type 316 stainless steel in solution annealed condition was irradiated by 4 MeV nickel ions at 773 or 873K under tensile stresses between 0 and 200 MPa. The irradiation dose was 3 or 50 dpa. Faulted loop microstructure and cavity microstructure were examined with a transmission electron microscope. The effects of applied stress were apparent in both cases, which proved the validity of the facility and the experimental method.
Relative number density of the interstitial type faulted loop appeared to increase when they have such an orientation that relaxes the tensile stress. The degree of such deflection of loop orientation was similar for 50 and 100 MPa of tensile stress. The size distribution of the faulted loops was not clearly affected by external stress.
As for cavity microstructure, an increasing tensile stress increased their mean size but did not clearly influence the number density. The observed stress dependence of cavity size distribution showed that a larger stress advances both the beginning and the end of cavity nucleation. Further microstructural examination suggested a possible effect of stress-enhanced precipitation on cavity nucleation.
Effects of Cascade Damage and Helium Production Under 600 MeV Proton Irradiation of Cu and Cu-Al2O3
Authors: Singh BN , Horsewell A 
Published: March 2009

Specimens of pure copper (oxygen free high conductivity grade) and a commercial dispersion strengthened Cu-Al2O3 alloy were irradiated with 600 MeV protons at 523 and 673 K to a dose level of about 0.5 dpa. The irradiation induced microstructure was investigated by transmission electron microscopy (TEM). The irradiation of copper with 600 MeV protons yields an average recoil energy of 2.3 MeV, giving rise to concurrent production of multi displacement cascades and helium (125 atomic part per million/displacement per atom) atoms.
The TEM investigation showed a complete absence of cavity formation in Cu and the Cu-Al2O3 alloy at the irradiation temperature of 523 K. At 673 K, cavities were observed in Cu but not in the Cu- A12O3 alloy. These results are compared with the results of neutron irradiations and α-particle implantations. The implications of these results are discussed particularly in terms of helium generation rate and recoil energy.
Factors Affecting the Susceptibility of Carbon-Manganese Steel Welds to Cracking in Sour Environments
Authors: Pargeter RJ 
Published: March 2009

Weldments in structural and pipeline steels have been characterized in terms of hardness and microstructure (using light and electron microscopy) and resistance to stress corrosion cracking (SCC) in NACE TM-01-77 test solution. In addition, the propensities of the steels for pitting and hydrogen pickup in NACE solution have been determined, and stress corrosion fracture surfaces have been examined in the scanning electron microscope.
The principal factor affecting susceptibility to SCC was hardness, after which the presence of martensite was the only factor that clearly increased risk of cracking. While there were marked differences in hydrogen pickup and pitting tendency, no direct correlation with risk of cracking was observed.
It is concluded that the use of hardness limits is applicable to carbon-manganese steel weldments operating in sour environments, but that compositional ranges over which such limits are used need to be determined. Attention is also drawn to the fact that the inter/sub critical heat affected zone (HAZ) could be the most susceptible region for cracking in some steels.
Fatigue Crack Initiation and Growth in Tensile-Shear Spot Weldments
Authors: McMahon JC , Smith GA , Lawrence FV 
Published: March 2009

Fatigue crack initiation and growth in SAE 960X steel tensile-shear spot welds were studied by sectioning companion specimens and by replicating the exposed site of crack initiation in a presectioned weldment. Constant-amplitude R = 0 and R = -1 tests, as well as variable-load history tests were performed on as-welded weldments and weldments peened (“coined”) after welding.
Approximately 50% of the total fatigue life was devoted to developing a 0.25-mm-depth crack under constant-amplitude loading in the life range 104 to 106 cycles. At lives greater than 106 cycles, this percentage appeared to increase. Similar results were found under a variable load history, although, in this case, only 40% of the life was devoted to developing a 0.25-mm-depth crack. Postweld coining increased the fatigue life by over an order of magnitude. Several analytical models for predicting the fatigue life of the tensile-shear spot weldments studied were compared.
The Effect of Fatigue Pre-Cracking Versus V-Notching on Impact Testing of Charpy Specimens
Authors: Fields BA , Low SR , Early JG 
Published: March 2009

Charpy impact testing was carried out on both V-notch and fatigue pre-cracked specimens of two steels: AAR M128, and ASTM A212-65. Values of total energy absorbed, lateral expansion and shear fracture appearance were found for both types of specimen. The total energies absorbed by the fatigue pre-cracked specimens were markedly less than those by V-notch samples.
Transition temperature ranges were found for both the V-notch and pre-cracked specimens. The energy absorption results show a small increase in transition temperatures for the pre-cracked specimens. The lateral expansion results are the same in both types of specimen for the AAR M128 steel and show only a small change in the ASTM A212-65 steel. Also for the A212 steel the shear fracture appearance results can be represented by a single curve for V-notch and pre-cracked specimens. However, for the M128 steel these curves occur at lower temperatures for the pre-cracked specimens.
A Multiaxial Fatigue Life Estimation Technique
Authors: Bannantine JA , Socie DF 
Published: March 2009

A method to estimate the fatigue life of a component subjected to variable amplitude multiaxial loading has been developed. The strain-life approach, which achieved success in correlating the fatigue lives of components subjected to uniaxial variable amplitude loading, is used as the foundation of this approach. The method incorporates critical plane multiaxial damage models that relate fatigue damage to remote loading parameters.
A computer model was developed to implement the proposed method. Measured or estimated strain histories are used as input. Corresponding stress histories are calculated using a nonproportional cyclic plasticity model. Damage is calculated using the stress and strain histories and multiaxial damage models. The plane experiencing the maximum damage is identified as the critical plane, and the fatigue life of the component is estimated from the damage calculations on this plane.
Experimental test results were used to evaluate and verify the proposed method. The measured stress-strain response of thin wall tubes loaded in combined tension and torsion were used to verify the nonproportional cyclic plasticity model. Good correlation between predicted and measured responses was observed. Results from tests conducted on SAE 1045 steel components, loaded in bending, proportional bending and torsion, and nonproportional bending and torsion, were used to evaluate the overall method. Good correlation between predicted and actual fatigue lives was achieved.
Life Prediction of Circumferentially Grooved Components under Low-Cycle Fatigue
Authors: Hatanaka K , Fujimitsu T , Shiraishi S , Omori J 
Published: March 2009

Stress-strain response was analyzed in the cross section of circumferentially notched components by the finite element method. Then, the cyclic J-integral range, ΔJ was estimated for the semielliptical surface crack and for the circumferential crack. The growth rate of the surface crack was successfully plotted against the estimated J-integral range under low-cycle fatigue loading.
Furthermore, the transition from the semielliptical surface crack to the circumferential crack, which occurred in the fatigue crack growth process in the acutely notched cylindrical component, was reasonably analyzed in terms of elastic-plastic fracture mechanics.
Finally, the low-cycle fatigue lives of the dully and acutely notched cylindrical components were satisfactorily evaluated through the analysis of the growth of the surface and circumferential cracks.
Analytical and Experimental Investigation of Fatigue in Lap Joints
Authors: Swenson DV , Chih-Chien C , Derber TG 
Published: March 2009

A finite element model is presented that can simulate crack growth in layered structures such as lap joints. The layers can be joined either by rivets or adhesives. The crack is represented discretely in the mesh, and automatic remeshing is performed as the crack grows. Because of the connections between the layers, load is transferred to the uncracked layer as the crack grows. This reduces the stress intensity and slows the crack growth rate.
The model is used to analyze tests performed on a section of a wing spanwise lap joint. The crack was initiated at a rivet and grown under constant amplitude cyclic loads. Both experimentally observed crack growth rates and the analysis show the retardation that occurs as a result of load transfer between layers. A good correlation is obtained between predicted and observed crack growth rates for the fully developed through-thickness crack.
Fatigue Lifetime Monitoring in Power Plants
Authors: Riccardella PC , Deardorff AF , Griesbach TJ 
Published: March 2009

Metal fatigue is a potentially life limiting mechanism for pressure retaining components in nuclear and fossil-fueled power plants. Fatigue cracking may occur at high stress locations due to the accumulation of startup-shutdown cycles and other thermal transients or load cycles during plant operation. This is accentuated in fossil power plants because of higher operating temperatures and the interaction between creep and fatigue effects.
Under sponsorship of the Electric Power Research Institute (EPRI), an automated fatigue lifetime monitoring technology has been developed that utilizes plant process data to perform a continuous prediction of fatigue damage accumulation in critical components. The methodology was demonstrated in two field tests at operating nuclear plants and has since been installed on a production basis in a number of plants. A demonstration fossil plant application has also been developed and installed, adding creep-fatigue damage and crack growth algorithms to the basic nuclear plant technology.
The methodology has been incorporated into a PC-based computer program called FatiguePro. This program acquires plant process computer data (temperatures, pressures, flows, valve positions, etc.) and interprets them to predict local loads and temperatures in the monitored components. Green's functions are then used to determine transient thermal stresses at high stress locations in these components and to account for thermal history effects. A fatigue evaluation is then made based on the computed transient stress history. The fatigue analysis, based on Miner's Rule, is accomplished in accordance with ASME Boiler and Pressure Vessel Code stress and fatigue analysis procedures. Methodology is also available to perform fatigue and creep crack growth analyses.
The major benefit of on-line monitoring is that the actual challenge to structural integrity is measured, instead of simply counting design-basis cycles, as was the practice before the development of this system. Since actual plant operating cycles are typically less severe than those included in design, extension of predicted design lifetime can usually be obtained.
Development of Spatial Data Guidelines and Standards: Spatial Data Set Documentation to Support Hydrologic Analysis in the U.S. Geological Survey
Authors: Fulton JL 
Published: March 2009

Spatial data analysis has become an integral component in many surface and subsurface hydrologic investigations within the U.S. Geological Survey (USGS). Currently, one of the largest costs in applying spatial data analysis is the cost of developing the needed spatial data. Therefore, guidelines and standards are required for the development of spatial data in order to allow for data sharing and reuse; this eliminates costly redevelopment. In order to attain this goal, the USGS is expanding efforts to identify guidelines and standards for the development of spatial data for hydrologie analysis. Because of the variety of project and database needs, the USGS has concentrated on developing standards for documenting spatial data sets to aid in the assessment of data set quality and compatibility of different data sets.
An interim data set documentation standard (1990) has been developed that provides a mechanism for associating a wide variety of information with a data set, including data about source material, data automation and editing procedures used, projection parameters, data statistics, descriptions of features and feature attributes, information on organizational contacts, lists of operations performed on the data, and free-form comments and notes about the data, made at various times in the evolution of the data set. The interim data set documentation standard has been automated using a commercial geographic information system (GIS) and data set documentation software developed by the USGS. Where possible, USGS developed software is used to enter data into the data set documentation file automatically. The GIS software closely associates a data set with its data set documentation file; the documentation file is retained with the data set whenever it is modified, copied, or transferred to another computer system. The Water Resources Division of the USGS is continuing to develop spatial data and data processing standards, with emphasis on standards needed to support hydrologic analysis, hydrologic data processing, and publication of hydrologic thematic maps. There is a need for the GIS vendor community to develop data set documentation tools similar to those developed by the USGS, or to incorporate USGS developed tools in their software.
An Approach to Data Exchange: The Spatial Data Transfer Standard
Authors: Rossmeissl HJ , Rugg RD 
Published: March 2009

Significant developments have taken place in the disciplines of cartography and geography in recent years with the advent of computer hardware and software that manipulate and process digital cartographic and geographic data more efficiently. The availability of inexpensive and powerful hardware and software systems offers the capability of displaying and analyzing spatial data to a growing number of users. As a result, developing and using existing digital cartographic databases are becoming very popular. However, the absence of uniform standards for the transfer of digital spatial data is hindering the exchange of data and increasing costs.
Several agencies of the U.S. government and the academic community have been working hard over the last few years to develop a spatial data transfer standard that includes definitions of standard terminology, a spatial data transfer specification, recommendations on reporting digital cartographic data quality, and standard topographic and hydrographic entity terms and definitions. This proposed standard was published in the January 1988 issue of The American Cartographer. Efforts to test and promote this standard were coordinated by the U.S. Geological Survey. A Technical Review Board was appointed with representatives from the U.S. government, the private sector, and the academic community to complete the standard for submittal to the National Institute of Standards and Technology for approval as a Federal Information Processing Standard. The proposed standard was submitted in February 1992 for final approval.