bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ductile Fracture Mechanisms in an A302B Modified Reactor Pressure Vessel Steel
Authors: Cuddy LJ , Manahan MP , Brauer G , Martinko J 
Published: March 2009

It has been demonstrated that thermal cycling of a previously quenched and tempered reactor pressure vessel (RPV) steel induces a hardness increase equivalent to an increase in flow stress of about 70 MPa. Single cycle heat treatments produce no such changes in hardness, flow stress, ductility or upper shelf energy (USE). Equivalent cycles will occur during reactor operation and may thus contribute to the observed changes during service of the properties of RPV steels. Preliminary microstructural examination offered no clear explanation for these effects, although it was observed that thermal cycling induced decomposition of retained austenite. It is demonstrated that, should the defects involved be shearable defects similar to those introduced by irradiation, they would promote ductile fracture by enhancing the growth and linking of microvoids and thus contribute to a drop in USE.
An analysis was performed which demonstrates that, of the several defects of the shearable type produced during irradiation of steels, vacancy clusters (or voids) are unstable with respect to both individual vacancies and collapsed vacancy loops. Thus, the latter defect and depleted zones would be the predominant vacancy hardening defects. Since irradiation produces both shearable (Cu/Ni/Mn rich precipitates, depleted zones, and loops) and non-shearable (Mo2C) hardening defects, it is important to resolve whether the shearable or non-shearable contribution is greater in order to be able to adequately model the effect on ductile fracture. For this purpose, a study of light water reactor (LWR) surveillance tensile data trends was performed and the results show negligible copper dependence of the yield strength change on fluence for fluences less than the boiling water reactor (BWR) end-of-license (EOL) fluence. These trends also show that the change in strain hardening behavior for U.S. steels is also negligible which indicates that shearable particles are the primary defect responsible for hardening. In addition to the Charpy curve shift, the shearable obstacles also cause a shelf drop during the strain controlled ductile fracture process. Rather than diffusing strain by slip plane hardening, as with non-deformable particles, shearable obstacles cause localization of strain in the unhardened slip plane. Strain localization in ligaments between voids leads to premature ligament failure in the irradiated material by the flow localization mechanism of void linkage.
Influence of Thermomechanical Treatment on Irradiation Microstructures in an ODS Ferritic Steel
Authors: Little EA 
Published: March 2009

The effects of thermomechanical treatment on microstructural changes and void swelling in a DT2203YO5-grade 13%Cr oxide-dispersion-strengthened (ODS) ferritic alloy have been studied following ion irradiations to a damage level of 50 dpa at 475°C with 600 appm helium gas implantation. Swelling in a solution treated and aged (STA) condition ranges from 0.07 to 0.24% due to cast-to-cast variations, whilst in a solution treated, cold-worked and aged (STCWA) condition the swelling decreases to 0.025%. Cavities are in general irregularly shaped, non-uniformly distributed and frequently attached to small yttria dispersoid particles.
The results confirm that this ODS ferritic steel exhibits low irradiation-induced swelling in the presence of high gas concentrations, as required for advanced fast and fusion reactor applications. The observed sensitivity of irradiation-induced swelling to compositional or processing variables implies that ODS ferritic alloys can be further optimized for high radiation resistance.
Effect of Boron on Post Irradiation Tensile Properties of Reduced Activation Ferritic Steel (F-82H) Irradiated in HFIR
Authors: Shiba K , Suzuki M , Hishinuma A , Pawel JE 
Published: March 2009

Reduced activation ferritic / martensitic steel, F-82H (Fe-8Cr-2W-V-Ta), was irradiated in the High Flux Isotope Reactor (HFIR) to doses between 11 and 34 dpa at 400 and 500°C. Post irradiation tensile tests were performed at the nominal irradiation temperature in vacuum. Some specimens included 10 B or natural boron (nB) to estimate the helium effect on tensile properties.
Tensile properties including the 0.2% offset yield stress, the ultimate tensile strength, the uniform elongation and the total elongation were measured. The tensile properties were not depend on helium content in specimens irradiated to 34 dpa; however 10 B-doped specimens with the highset levels of hilium showed slightly higher yield strength and less ductility than boron-free specimens. Strength appears to go through a peak, and ductility through a trough at about 11 dpa. The irradiation to more than 21 dpa reduced the strength and increased the elongation to the unirradiated levels.
Fatigue Crack Propagation by Channel Fracture in Irradiated 316 Stainless Steel
Authors: Jitsukawa S , Hishinuma A , Suzuki M 
Published: March 2009

Fatigue crack growth rates (da/dN)in an irradiated cold worked 316 stainless steel were obtained at temperatures of 298, 573 and 673 K. Specimens were prepared from a duct material, which irradiated at 683 K to 20 displacements per atom in an experimental fast breeder reactor.
Fatigue loading caused channel fracture to occur in the irradiated material. This was accompanied by acceleration of da/dN. Both the increment of da/dN and the fraction of channel fracture in fracture surface became larger with stress intensity factor range at temperatures of 573 and 673 K, but they were not at 298 K. Results indicate that irradiation induced channel fracture increased da/dN.
Data Collection on the Effect of Irradiation on the Mechanical Properties of Austenitic Stainless Steels and Weld Metals
Authors: Tavassoli A-A , Picker C , Wareing J 
Published: March 2009

Data on the influence of low dose 400–550°C irradiation on the mechanical properties of structural steels (Types 304, 316, 316L, 316H and 316L(N) and associated weld metals) at temperatures from 20°C to 750°C, have been compiled from published literature and the results of British, Dutch, French and German laboratories. Properties evaluated include tensile, impact, creep, fatigue, and creep-fatigue. The preliminary results, which cover the dose range from 0 to 5 displacements per atom (and/or up to 9 appm helium) are presented as comparisons between irradiated and unirradiated control data, covering a range of strength and cyclic properties. The results show that low dose irradiation can have a significant influence on the properties, i.e.:• increases in tensile proof strength,• reductions in tensile ductility,• decreases in impact energy,• reductions in creep-rupture strength and ductility, and • reductions in creep-fatigue endurance.
By considering the influence of irradiation temperature and dose level, the results are rationalised in terms of irradiation hardening and grain boundary embrittlement mechanisms.
Bubble Microstructure Evolution and Helium Behavior in He+ Implanted Ni-Base Alloys
Authors: Kalin BA , Chernov II , Kalashnikov AN , Solovyev BG 
Published: March 2009

Behavior of ion-implanted helium in Ni as a function of alloying element concentration (Al or Ti) and irradiation conditions (at 20 or 750°C) have been investigated by means of thermal desorption spectrometry (TDS) and transmission electron microscopy (TEM).
Substitution elements in solid solution were demonstrated to have substantial influence on the evolution of implanted helium, shifting the TDS spectrum peaks to higher temperature region and increasing the quantity of helium remaining in the samples after long-time postirradiation annealing. TEM investigations showed that in the case of postirradiation annealing, helium bubbles are formed earlier in quenched alloys than in those annealed. In the high-temperature irradiated alloys, the bubbles formed are smaller in size and higher in density than in the case of postirradiation annealed samples irradiated at room temperature. Alloying elements reduce bubble diameter and increase bubble number density. This is especially typical for concentrations of alloying elements that exceed the ultimate solubility in nickel.
Corrosion Response of Pre-Irradiated Zr-2.5Nb Pressure Tube Material
Authors: Urbanic VF , Griffiths M 
Published: March 2009

Out reactor corrosion testing of Zr-2.5Nb pressure tubes in moist air at 573 K has shown that the pre-irradiated samples, i.e. those fabricated from tubes removed from power reactors, were more corrosion resistant than their unirradiated counterparts. The pre-irradiated materials had lower pre-transition corrosion rates, longer times to transition and lower post-transition rates than unirradiated material. As the samples were prepared equally in each case by polishing to bare metal, it is clear that the microstructural changes produced during irradiation are responsible for the improved corrosion response. For this reason X-ray diffraction (XRD) and analytical electron microscopy (AEM) have been used to characterise microstructural and microchemical changes produced by neutron irradiation of Zr-2.5Nb pressure tubes during service.
There is a positive effect of irradiation in improving the corrosion response down to fluences of at least 1×1025 n/m2 (E&gt;1 MeV). However, despite the reduction in corrosion, the amount of deuterium absorbed, as a fraction of the total deuterium generated by the corrosion process, was about ten times higher for the irradiated material than for the unirradiated material.
The results of the analyses indicate that improvements in corrosion behaviour may be linked with decreases in the Nb concentration in the α-Zr matrix due to Nb precipitation during irradiation. However there is no clear indication as to the cause of the increased deuterium uptake.
Effect of Preform Architecture on Modulus and Strength of Two-Dimensional, Triaxially Braided, Textile Composite Materials
Authors: Masters JE , Minguet PJ 
Published: March 2009

This paper investigates the mechanical response of two-dimensional, triaxially braided, textile composites from an experimental viewpoint. The specific objective of this study was to empirically define the role of the braid architecture in determining laminate mechanical properties. Three primary braiding parameters, that is, braid angle, 0° yarn content, and yarn size, were identified. A number of reinforcing fiber architectures were designed to provide a direct comparison of the effects of these parameters on mechanical performance. These parameters were varied over a wide range to establish data that reflect the full spectrum of viable braid architectures. Braid angle varied from 45° to 70°, 0° yarn content ranged from 12 to 46%, and yarn bundle size ranged from 6 thousand fibers per bundle to 75 thousand fibers per bundle. The laminates studied featured AS4 graphite fibers in Shell's 1895 epoxy matrix.
In addition, two secondary braiding parameters, 0° yarn spacing and yarn crimp, were also investigated. A set of laminates was designed to isolate the effects of these two parameters.
The effects of fiber architecture on the mechanical performance are thus further defined in the investigation. Experimental results will include measures of the materials' longitudinal and transverse tensile moduli, their Poisson's ratios, and their shear moduli. In addition, the effects of the textile preforms' architecture on laminate tensile strength will also be reviewed.
Municipal Solid Waste Sampling and Characterization
Authors: Brokaw WS , Hornberger GS 
Published: March 2009

The character and composition of solid wastes need to be determined for a variety of objectives. These objectives include developing design criteria for resource recovery facilities, determining performance efficiency, and evaluating source reduction initiatives (e.g. recycling).
The techniques described in this paper are for the collection and characterization of municipal solid waste and can be employed at resource recovery facilities, transfer stations and sanitary landfills. The results have been used in conjunction with emissions testing and ash analyses to calculate a mass balance for an incinerator at a resource recovery facility.
The technique utilized is an adaptation of several related ASTM methodologies developed for sampling and analyzing refuse derived fuel. Representative waste samples are manually collected from trash collection vehicles (rolloff containers, compactor trucks, etc.) as they unload. The discrete samples are collected and composited during a predetermined period. Each composite sample is mixed and characterized on-site and a portion recovered and prepared for laboratory analyses.
A significant amount of data can be generated from the sampling such as the mass and percent of recyclable materials, heating value, and elemental composition (proximate and ultimate parameters). The sampling technique can be readily modified to obtain the desired data.
Microbeam Analysis of Heavy Element Phases in Polished Sections of Particulate Material — An Improved Insight into Origin and Bioavailability
Authors: Kennedy SK , Casuccio GS , Lee RJ , Slifka GA , Ruby MV 
Published: March 2009

The contamination of environmental materials (soil and dust) by heavy elements is of concern in assessing environmental pollution. Characterization of samples is performed in order to provide information that can be used to assess the potential hazard of the material, to assess remediation strategies, and to determine the source of the heavy element-bearing material. This is difficult because the particles in which the element of interest occur may consist of multiple phases, some potentially hazardous and some benign. Bulk properties of samples are often determined to assess the potential risk related to such a sample. Such an assay may reveal the total content of a contaminant, and so document the maximum hazard potential, but cannot directly address important mitigating factors, including the specific phases present, their size distribution and internal particle structure.
Microbeam analysis using a scanning electron microscope (SEM) or electron microprobe on polished particle mounts allows the size, internal morphology and chemical composition to be determined on a particle-by-particle basis. Computer controlled SEM allows all factors except internal structure to be acquired in an automated fashion.
We present examples of two studies using microbeam techniques. In the first example, we illustrate how cadmium associated with sphalerite (zinc sulfide) in soils can be quantified at levels down to a few parts per million (ppm) using computer controlled SEM techniques. In the second example, we illustrate how lead in soils can be assigned to phases, phase sizes and to internal structure types using manual electron microprobe techniques.
Reducing Stress Related Problems in Steel Forgings Using Sub-Harmonic Vibrational Energy
Authors: Hebel TE 
Published: March 2009

There are predominantly three residual stress related problems plaguing steel forgings. They are 1) distortion following machining, 2) delayed distortion, and 3) premature cracking tendencies. The major source of these problems is the stress caused by a sharp temperature drop from hot forging or welding.
This paper will detail SUB-harmonic vibrational technology as an effective stress relief solution to reducing these problems. Also, this paper will outline the three step approach for using the sub-harmonic energy process during welding. When used during welding additional benefits of reducing weld distortion and cracking will be achieved.
Data collected from seven Test Cases will be presented including reduced machine distortion (43–76%) from forged cannon barrels and aerospace components. Reducing premature cracking will be demonstrated using examples of longer fatigue life (200–400%) from components such as forged crankshafts and connecting rods used in racing engines. Data from the U.S. Department of Energy sponsored study on this technology will be presented. This report concluded that there is evidence that the Sub-harmonic treated and thermal stressed relieved specimens are “comparable.”
Ultrasonic Signal Processing Using Indication Sets for Detection and Characterization
Authors: Viertl JRM 
Published: March 2009

The potential for discontinuities in turbine and generator rotors must be dealt with in the manufacture of these components. In recent years it has become practical to acquire and analyze large quantities of ultrasonic data obtained from testing solid rotor forgings.
This paper describes an ultrasonic system for testing solid rotors, and discusses the detection, characterization, and imaging capability developed for evaluating rotor indications.
For detection of rotor indications, the ultrasonic signal path is divided into range windows. The signals within each window are compressed and stored for detection and characterization algorithms. Detection is performed by associating echoes from one ultrasonic path with the data from neighboring paths. These associations are constructed with respect to the cylindrical coordinate system used during the process.
Characterization is performed using the indication data sets constructed during the detection process. The final results determined by these automatic data processing algorithms are presented to the user as potential indication lists which can be correlated to images constructed from the original data.
A Rare Type of Flake-Like Forging Burst in Heavy Forgings
Authors: Steiner JE , Murphy EL 
Published: March 2009

Forging bursts are infrequently reported in the published literature. One type of forging burst, which has been observed only on four occasions in the combined experience of the authors, is described. The similarity of this defect with hydrogen-caused thermal flakes is remarkable. It is characterized by a fracture appearance similar to that of flaking when broken open, by orientation and distribution similar to flaking, but within a specific section of a large forging, generally in ultrasonic test response and by its good response to healing during reforging, as with flaking.
Case histories of two 3.5Ni-Cr-Mo-V forgings, one 1cr-1Mo-0.25v forging and one martensitic stainless steel forging are presented, and processing factors related to these bursts and means for avoidance of the problem are discussed. A fifth case of possible misidentification of this phenomenon as hydrogen flakes in a small gear component forging is discussed. Approaches to differentiation of this defect from flaking are discussed.
Martensitic 11% CrMoNiNb Steel for Turbine Rotors in Geothermal Power Stations
Authors: Schonfeld KH , Levacher R , Manning MP , Murley PF 
Published: March 2009

Turbine rotors in a geothermal power station were required in high alloyed 12% Cr steel. After some preliminary investigations it was found that a modified 11% CrMoNiNb steel will fulfil the required mechanical properties as well as a sufficient resistance to corrosion.
Two LP rotors with appr. 1 295 mm (51 in.) premachined diameter and ungashed weight of appr. 31 mt were manufactured. The steel was melted in a 125 mt electric arc furnace and subsequently remelted into a 113 mt ESR ingot with 2 300 mm (90 in.) diameter. After forging and preliminary heat treatment the rotors were quality heat treated to a yield strength (0.2% and 0.02%) of appr. 600 MPa (87 ksi) and appr. 550 MPa (80 ksi) respectively and tensile strength of appr. 780 MPa (113 ksi). This resulted in a FATT of appr. 16‡C (60‡F). Low hardness is important to susceptibility to stress corrosion. It was achieved to appr. 20 HRC.
The results have met the assumption with respect to this steel for application as rotor material for geothermal power stations.
Field Measurement of the Corrosion Rate of Steel in Concrete using a Microprocessor Controlled Unit with a Monitored Guard Ring for Signal Confinement
Authors: Broomfield JP 
Published: March 2009

The principle of corrosion rate measurement by the linear polarisation resistance method is simple. The equipment measures the half cell potential, applies a small current and measures the change in potential. The corrosion rate is proportional to the applied current divided by the potential shift.
Using the technique in the field on reinforced concrete structures is complicated because the area of measurement must be defined and readings fluctuate with the weather conditions.
This paper describes the use of a corrosion rate device in Europe and the USA on bridges, buildings and other structures. Its application for measuring the effectiveness of chloride removal and other rehabilitation techniques is discussed.
A Case Study: Assessment of Ice Rink Refrigerant Tubing Corrosion using Half Cell Techniques
Authors: Brickey WJ 
Published: March 2009

This paper describes a corrosion study performed on an ice rink. The purpose of the study was to evaluate the extent and increase in corrosion of low carbon steel refrigeration tubes and the reinforcing steel embedded in a concrete slab-on-grade. A copper-copper sulfate half cell was used in the assessment. Chemical analyses, microscopic examinations and destructive examinations were used to supplement and confirm the results of the half cell testing.
An increase in corrosion activity was determined by comparing the results of half cell surveys conducted in 1989 and 1990. The cause of the corrosion activity was determined from chemical analyses, microscopic examinations and destructive techniques.
Development of Specifications for Mortar Cement
Authors: Melander JM , Ghosh SK 
Published: March 2009

A specification for mortar cement was incorporated into the Uniform Building Code (UBC) Standards by the International Conference of Building Officials (ICBO) in 1991. This action was taken on the basis of recommendations made by the Masonry Industry Code Committee (MICC), a volunteer committee of producers, general interest, and user individuals, which coordinates masonry industry input with respect to the UBC and UBC Standards. The UBC Mortar Cement Standard represents the culmination of research and standards development effort that was coordinated by the MICC. More recently, ASTM Subcommittee C01.11 on Masonry Cement has undertaken action to develop an ASTM consensus standard for mortar cement.
This paper examines the research, rationale, and events that led to the development of the UBC mortar cement standard, explains how mortar cement differs from masonry cement in use and requirements, and discusses key issues being considered in the development of an ASTM Standard Specification for Mortar Cement.
An Evaluation of Bond Wrench Testing Apparatuses
Authors: McGinley WM 
Published: March 2009

Summarized are results of a combined testing and analytical investigation of four different bond wrench testing systems. The testing program involved placing a calibration block within each testing apparatus and applying a range of loads to the block. This calibration device was designed to simulate a standard brick couplet specimen and was instrumented with linear strain gauges which were monitored and recorded during loading. The results of these tests were compared and discussed in an effort to determine what attributes of the testing apparatuses can significantly affect the stress distribution in masonry couplet specimens. Evaluation of the bond wrench testing system was also performed using a finite element analysis.
Finally, in an effort to extend the scope of C 1072 -92 to include hollow masonry assemblies, an analytical evaluation of hollow couplet specimens was made. The results of these finite element analyses are presented and discussed.