bluuebunny/crossref_metadata_2025 huggingface dataset:
Strength and Fracture of 5083-0 Aluminum Weldments
Authors: Zinkham RE , Ashton RF
Published: March 2009

The mechanical performance of 1 ¾-in. (44 mm) 5083-0 weldments was examined at room temperature and at -320°F (-196°C). The welds were made using 5183 and 5356 electrodes and three variations of the gas metal arc process; these were a twenty-pass vertical procedure, a two-pass high-current flat position method, and a one-pass vertical electrogas technique. It was determined that the tensile and yield strengths of the entire weldments, heat-affected zones and weld metals increased with decreasing test temperature. Both 5356 and 5183 filler alloys produced welds which met the existing codes and specifications; however, 5183 was preferred because it resulted in slight increases in strength with no sacrifice in ductility or toughness. In comparison with multipass welding, the high-current method produced welds with low defect levels and, therefore, higher tensile strengths and elongations. The high-current and electrogas weld yield strengths were respectively less due to coarser microstructures. The notch sensitivity and resistance to a propagating crack were slightly lower for weld metal than for the base plate or heat-affected zone at -320°F. This trend was particularly evident for the high-current welds. However, the toughness of all 5083-0 welds was indicated to be high, and structural failures would be unlikely to occur at elastic stresses unless cracks were very large.
Low Temperature Fracture Behavior of Iron-Nickel Alloy Steels
Authors: Tobler RL , Mikesell RP , Durcholz RL , Reed RP
Published: March 2009

Fracture toughness tests over the interval 298 to 4 K and fatigue crack growth rate tests at 298, 111, and 76 K are reported on selected iron-nickel (Fe-Ni) alloys which are commercially available for potential use in storage or transportation of liquefied natural gas (LNG). These alloys include Fe-6Ni and Fe-5Ni in newly developed three-step heat treatments and Fe-9Ni in the quenched and tempered condition. Linear elastic fracture mechanics parameters (KQ, KIC) and J-integral (JIC) test data are presented for 1.25-in.-thick compact specimens. Discussion includes comparisons of fatigue crack growth rate and fracture data between alloys.
Strength and Fracture Toughness of Nickel Containing Steels
Authors: Haynes AG , Firth K , Hollox GE , Buchan J
Published: March 2009

Having relatively high yield strength at liquefied natural gas (LNG) temperatures, nine percent nickel steel offers scope for some increase in design stresses for LNG structures with attendant economies in cost. This paper presents corroborative fracture toughness data for small specimens and wide plate tests that indicate favorable behavior and conditions for high stress designs.
Newly Developed Welding Material for Liquefied Natural Gas Application
Authors: Nishi T , Saito S , Nakano T , Horii Y
Published: March 2009

The purpose of this study is to put the 37Ni-6Mn-10Cr type weld metal to practical application for the gas metal arc (MIG) welding of 9Ni steel. The effect of molybdenum, tungsten, and nitrogen on the strength and notch toughness of weld metal and the effect of silicon and sulfur on the hot crack sensitivity were examined. Then the joint efficiencies of MIG weldments made with an optimum level of filler wire chemical composition were examined varying heat input of welding and plate thickness. The center-notched wide plate tension test was conducted in order to assertain the satisfactory performance of this filler wire in comparison with the conventional 70Ni type filler wire. This filler wire is applicable for Ar-Co2 gas shielded arc welding, which produces stable arc and good penetration, thus preventing from occurrence of lack of fusion.
Monitoring Ground Movements Adjacent to an Excavation in Downtown Chicago
Authors: Lukas RG , Anderson DE
Published: March 2009

A high-rise building constructed in downtown Chicago was monitored for ground movements. The below-grade excavation consisted of two parts: the installation of drilled caissons through the underlying soft clay to hardpan, or in most cases to the limestone bedrock at a depth of 110 ft; and the excavation for a double-level basement to a depth of approximately 25 ft below grade. The monitoring of ground movements was considered essential at this site because it is located in downtown Chicago with adjacent buildings, utilities located in the streets and alleys, and an elevated transit system along the western boundary which is supported on shallow foundations. Monitoring was accomplished by two separate means. Ground surface elevations and lateral movements were taken at many points, including the foundations of the elevated structure and the streets, by surveying methods. Two inclinometer stations were installed and read on a periodic basis to measure the variation in horizontal movement with depth below grade. A correlation was established between the lateral survey readings and the inclinometer readings. The monitoring system was sufficiently accurate to record the observed settlement as a function of the construction activity. This paper is limited to a description of the instrumentation, the soil conditions, and the observed readings related to the various phases of construction.
Monitoring Consolidation Settlements of Soft Soils Induced by Dewatering
Authors: Partos A , Koerner RM
Published: March 2009

A case study of induced, consolidation settlements using wellpoint dewatering is presented. Included are a site description, results of laboratory tests, and details of an elaborate monitoring system consisting of water observation pipes, bench marks, settlement plates and anchors, piezometers, and nuclear density and moisture-content probes. A critique of each type of instrumentation is included in the paper. Five thousand field observations show that the wellpoint technique can produce predictable consolidation settlements.
Soil Strain Measurement Using Inductance Coil Method
Authors: Selig ET
Published: March 2009

Past field experience using the inductance coil system for soil strain measurement is summarized. The purpose is to illustrate the usefulness of measuring strain as well as to show the advantages and limitations of the instrumentation system. The examples include soil compaction, soil-structure interaction, and traffic-induced strains.
Static and Dynamic Strain Measurements for Embankments
Authors: Dietrich RJ , Salley JR
Published: March 2009

The U.S. Department of Transportation and the Atchison, Topeka, and Santa Fe Railway Co. (ATSF) are jointly sponsoring a railroad test embankment on the main line of the ATSF system. The test embankment is nearly 2 miles long and is comprised of a minimum thickness of 6 ft of compacted, highly plastic clay. The embankment is divided into nine test sections, each with a unique track support system but having identical embankment instrumentation.

This paper discusses the considerations leading to final design, fabrication, and installation of the embankment instrumentation. The embankment instrumentation was developed to provide quantitative data on embankment performance and response to aid in the comparative evaluation of track structure performance. Emphasis was placed on reliable measurements of dynamic embankment strain. Provisions for measurement of long-term deformations and volume changes in the highly plastic clay embankment were also provided. Each of the nine test sections has one principal instrument array supplemented by additional instruments spaced to verify that the performance at the main arrays is typical for that test section. The main array instrumentation includes vertical extensometers, portable horizontal extensometers which will be inserted in flexible horizontal tubing embedded in the embankment, pressure cells, and moisture-temperature cells. The instrumentation was specifically designed for this project.
Effects of Very Low Pressures on Fatigue Fracture Surface Features in Ti-6Al-4V
Authors: Meyn DA
Published: March 2009

The amount and quality of quasi-cleavage and possibly the crack growth rates caused by fatigue of Ti-6Al-4V in vacuum were enhanced by increasing hydrogen content and decreasing cyclic loading frequency. Precision matching studies of pseudo-striations on mating vacuum fatigue fracture surfaces lead to the tentative conclusion that these do not mark successive positions of the crack front, hence are not fatigue striations. Similar studies of quasi-cleavage areas show that tear ridges mate exactly, suggesting that such cracking proceeds by a combination of micro-cleavage crack initiation and microplastic coalescence of the micro-cracks.
Fractographic Features in Eutectic Composites
Authors: Stoloff NS , Duquette DJ
Published: March 2009

An extensive literature has emerged on the flow and fracture behavior of aligned eutectic composites. However, there have been few attempts to systematically record and compare fractographic features in eutectics as a function of microstructural variables (for example, interfiber spacing) or test conditions (for example, temperature, load application). This paper constitutes a compilation and evaluation of fractographic features from specimens loaded parallel to the eutectic growth direction, obtained by scanning and transmission electron microscopy from the following fibrous alloys: Al-Al3Ni, Ni,Cr-TaC, and Co,Cr,Ni-TaC; and lamellar alloys: Ag3Mg-AgMg, Mg17Al12-Mg, and Al-Ag2Al. Tensile, creep, and fatigue loading at a variety of test temperatures are included for several of these alloys. It will be shown that fatigue fracture morphology is particularly sensitive to microstructural variables. For example, a shift from striation-free Stage I cracking to profusely-striated Stage II cracking in Ag3Mg-AgMg is obtained by post-solidification heat treatment.
Fracture Feature Anisotropy in a Martensitic Steel Plate
Authors: Sailors RH
Published: March 2009

The three mutually-perpendicular fracture plane orientations in a martensitic steel plate were examined both metallographically and fractographically. The nonuniform distribution of inclusions and anisotropy in inclusion shape produced different appearing fractures, yet all were microscopically ductile. Detailed examination of fracture surfaces and fracture surface profiles illustrated the extent of void growth from sulfide inclusions before macroscopic fracture. Comparisons of cementite nucleated void size and prior austenite grain size showed that only a few cementite particles nucleated voids whereas many hundreds existed per prior austenite grain. A mathematical characterization of inclusion distribution illustrated that effective volume fraction of inclusions was dependent on fracture plane orientation and aided in the understanding of anisotropy in fracture strain. This investigation emphasized the compatibility of conventional metallography and stereofractography in analyzing the fracture process.
Cyclic Plasticity of Copper at the Surface and in the Interior
Authors: Nakano Y , Sandor BI
Published: March 2009

The cyclic plastic strain ranges were determined in the surface layers (material containing persistent slip bands) and inside the specimens. In the experiments several stress amplitudes, several average grain sizes, and two environments were used. The cyclic plastic strain range inside a specimen was constant throughout the fatigue life, but in the surface layer it was high early in the life and decreased throughout the life. The largest cyclic plastic strains in the surface layer were about two orders of magnitude larger than those inside the specimen. The mechanical surface effect involved a layer of metal with a thickness of about four average grains.
A Fractographic Study of the Edge-Sliding Mode in Fracture Toughness Testing
Authors: Jones DL , Chisholm DB
Published: March 2009

A fractographic study of Mode II fracture surfaces has been conducted for the purpose of identifying the microstructural mechanisms responsible for fracture in the edge-sliding mode. A compact shear (CS) specimen developed by the authors was employed to generate the fracture surfaces and also to establish Mode II fracture toughness values (KIIc) for Ti-6Al-4V, A533-B steel, and several aluminum alloys. In all tests, one of the two edge cracks sustained complete Mode II fracture while the other exhibited only a limited amount of subcritical crack growth. Mode II fracture surfaces, which were unique in appearance, have been examined by optical and scanning electron microscopy.

It was determined that shear (or parabolic) microvoid coalescence was the dominant mechanism for Mode II fracture. The smallest dimples were about ½ to 1 µm in diameter and were about the same size for all alloys studied. However, a significant portion of the fracture surfaces were abraded against their mating crack surfaces so that no initiation mechanisms could be observed in these regions. It was established that most of the surface abrasions were created by the relative sliding of the fracture surfaces during unstable fracture rather than the crack initiation process. Some tendency for brittle fracture on crystallographic planes of maximum shear was also observed.
Sensory Methods — Choices and Limitations
Authors: Larmond E
Published: March 2009

Several methods of sensory evaluation have been developed, and each has its advantages and disadvantages. The experimenter must be aware of these and select the most practical and efficient method in each situation. The form of the results obtained depends on the method used and determines what further treatment can be applied to the data.
Search for the Determiners of Food Quality Ratings — Description of Methodology with Application to Blueberries
Authors: Bargmann RE , Wu L , Powers JJ
Published: March 2009

The object of this study is to relate qualitative and quantitative ratings as expressed by judges and to relate sensory responses to physical measurements and gas chromatograms. Judges were asked to rate acceptability, flavor, and mouthfeel of blueberries on a five-point scale in a darkened room. With another specimen, they were asked to judge appearance and color without, however, tasting these berries. The judges were also asked to complete a questionnaire describing, in qualitative terms, the characteristics of each specimen. Varieties were subjected to analysis by physical and chemical measurements, and gas chromatograms were prepared. Contingency analysis and analysis of variance were performed to relate qualitative and quantitative ratings. The relationship between physical measurements or chromatograms and ratings is displayed in tables of means; although these numbers can be expressed as single correlations, using a random model, a single measure based on just four products was deemed to be less informative than a tabulation of correspondence.
Response Surface Methodology and Subjective Data
Authors: Wells ME
Published: March 2009

The use of quadratic models in two or more variables to describe a subjective response is discussed. Attention is given to the principles of experimental design as well as to any special problems incurred by the use of ranking or rating data as a response. An example taken from the textile area serves as an illustration.
Applications of Multidimensional Scaling to the Psychological Evaluation of Odors
Authors: Moskowitz HR
Published: March 2009

The use of multidimensional scales is outlined for two problems in odor perception. Multidimensional analyses of profile data allow the experimenter to obtain, at a glance, the necessary information about qualitative relations among odorants and their linguistic descriptors, as well as changes in the perception of the same odorant evaluated across time. All can be represented by the analysis procedures of multidimensional scaling.
Experiences with Subjective/Objective Correlation
Authors: Powers JJ
Published: March 2009

Practical knowledge acquired during a decade of devising methods for the correlation of sensory evaluation for flavor with gas-liquid chromatographic analysis of food volatiles is described. The evolution of methods, precautions that should be taken with each method, limitations of the methods, and minimizing of experimental error on the sensory and objective sides are discussed.
Formability and Fracture of Some Higher Strength Aluminum Alloys
Authors: Sowerby R , Sareen BK
Published: March 2009

This work presents the comparative behavior of some formable grades of aluminum alloy sheet and an aluminum killed drawing quality (AKDQ) steel sheet in a number of formability tests. Tensile data were assembled from specimens cut at different orientations in the plane of the as-received sheet. An attempt was made to fit the stress-strain data with an empirical equation of the form σ¯ = k (ϵ0 + ϵ¯)n. The following quantities were also obtained from the tension tests: uniform strain, the plastic strain ratio (r value) and fracture strain. The aluminum alloys showed inferior r values and lower values of fracture strain when compared with the steel sheet; the n value did not always correlate well with the measured uniform strain in the alloys.

The aluminum alloys were deformed under different conditions of biaxial straining by stretching over a rigid punch, and forming limit diagrams were constructed. From the same test it was also possible to assess the fracture strains. The fracture thickness strain does not appear to be a single valued material property but can be dependent upon the deformation mode rather like the limit strain.

Additional tests performed on the materials included bulging in a circular die under hydraulic pressure, an in-plane torsion test, and an in-plane stretch test designed to promote a plane-strain deformation mode. The results from these tests supplemented the limit and fracture strain data gathered from the punch-stretch tests.

The aluminum alloys could be formed but showed inferior formability to the AKDQ steel. The lower fracture strains exhibited by the alloys may influence the behavior in certain plastic forming processes in a manner that would not be anticipated on the basis of n value predictions.
Bending and Springback of Aluminum Alloy Sheet and Plate
Authors: Rolf RL , Patrick EP
Published: March 2009

A practical method was developed to predict the minimum bend radius and the amount of springback of aluminum alloy sheet and plate. Analytical equations describing the mechanics of bending were used and were correlated with extensive 90-deg air bend test results of alloys 2024-T3, 3003-H14, 5052-H32, 5083-O, 6061-O, 6061-T4, 6061-T6, and 7475-T6. The method utilizes the fracture strain obtained from a bend test or tension test in the minimum radius prediction and the mechanical properties obtained from a tension test in the springback prediction.
Development of Forming Limit Curves for Aerospace Aluminum Alloys
Authors: Hursman TL
Published: March 2009

The objective was to develop forming limit curve (FLCs),tensile(elastic and plastic) properties, and production stretch-form test data for two alloys.

A laboratory technique developed by Hecker and his associates at General Motors Research Laboratories was used to develop FLCs for 2024-T3 and 2219-T31 aluminum alloys. This laboratory technique involves biaxial punch-stretch testing of sheet metal specimens clamped securely between two die plates at the periphery. Using this technique, the influences of sheet thickness, lubrication, blank size, and blank orientation on forming limits were investigated.

The values of the strain-hardening exponent and plastic strain ratio calculated for 2024-T3 and 2219-T31 aluminum alloys are in good agreement with those for other aluminum alloys reported by Hecker. The strain-hardening exponent, n, was found to be higher for 2219-T31 than for 2024-T3. The average plastic strain ratios, r, for 2024-T3 were higher than for those for 2219-T31 in all three test directions.

All FLCs measured in the laboratory were found to be in good agreement with production stretch-form test data.
Use of Calcium in Inclusion Shape Control of High-Strength, Low-Alloy Steels Produced by the Direct Reduction-Electric Furnace Process*Original experimental data were measured in U.S. customary units.
Authors: Hastings PR , Drolet R
Published: March 2009

The use of a high charge of reduced pellets (91 to 94 percent iron) in the electric furnace enables steels containing a maximum of 0.010 percent sulfur to be obtained without desulfurization. A typical sulfur value is 0.007 percent for a 100 percent pellet charge. At such low sulfur levels, it is shown that good inclusion shape control is obtained by simple additions of calcium silicon to the ladle. Various methods of evaluating transverse ductility in hot-rolled, high-strength, low-alloy (HSLA) steels are compared. A relationship is obtained between the ratio of transverse to longitudinal Charpy shelf energy values and projected inclusion length, which is upheld for a wide range of steel compositions. A minimum Charpy ratio of 0.7 is required for a given severe stretching application. The influence of manganese and sulfur contents on transverse ductility is also considered.
Determination of Ductility for Bulk Deformation
Authors: Woodall SM , Schey JA
Published: March 2009

The possibility of predicting the onset of fracture in bulk deformation processes from ductility parameters determined in simple tests was investigated by performing uniaxial tension, plane-strain tension, partial-width indentation, and secondary tension tests on 6061 aluminum, 1020 and 1045 steels, and lead. Limiting strains were correlated with those measured in upsetting with sticking at the end face and in rolling. Uniaxial tension was inapplicable, but the other tests showed reasonable agreement with a ductility criterion giving a ½ slope in a major (tensile) versus minor (compressive) strain plot, at least for isotropic materials. Normal anisotropy made the relationship invalid, with a much larger compressive or rolling strain attainable when the plastic strain ratio (r value) was less than unity.
Workability Testing and Analysis for Bulk Forming Processes
Authors: Kuhn HA
Published: March 2009

A workability test procedure has been developed using cylindrical upset tests and bend tests. Variation of the upset specimen aspect ratio (height-to-diameter ratio) and of lubrication of the compression dies produces a variety of stress and strain combinations at the free surface of the cylinders. Bend tests extend the range of available stress and strain states, and are also useful in cases where cylindrical upset test specimens are impractical. In either test, measurements of grid deformations at the surface permit calculation of the surface strains and, with the aid of plasticity equations, surface stresses.

Results show that the surface tensile and compressive strains at fracture fit a straight line relationship having a slope of −½ and an intercept along the tensile strain axis. The intercept depends on material, composition, structure, and surface condition. Such results have been found for a variety of ferrous and nonferrous alloys, as well as sintered powder metals at cold and hot working temperatures.

The fracture-strain relationship determined by workability tests can be used for workability analysis of bulk-forming processes. Progressive strain relationships in critical regions of the workpiece of interest are determined through plasticity analysis or through measurements on model materials. These relationships are compared with the fracture strain relationship to determine the likelihood of defect formation and to suggest alterations of the process for improved workability. This approach has been used for analysis of cracking in various modes of flow generic to forging, such as formation of hubs, flanges, rims, and gear teeth; it has been also applied to specific forged parts.
Analysis of Sheet Metal Forming to Axisymmetric Shapes
Authors: Levy S , Shih CF , Wilkinson JPD , Stine P , McWilson RC
Published: March 2009

The objective of this study was to develop an analytical method of predicting the stress and strain distribution in a metal sheet formed into a cup or other axially symmetric geometry. The analysis is done using the finite element method based on the deformation theory of plasticity; the elastoplastic computations account for the large deformation associated with sheet forming operations. The theory behind the computer program is discussed in detail. Examples are given of the strain distributions induced in cups drawn to depths comparable with their diameters. The results also give the stresses, thickness changes, and forming force required. Some comparisons between the calculated and measured strains are discussed, and they show good agreement.
Multicylinder Test Sequences for Evaluating Automotive Engine Oils: Part 1: Sequence IID
Authors: Committee D02
Published: March 2009

Description

The test method described in this publication has not been subjected to the ASTM Standardization Procedure. It is not a standard recommended practice of the American Society of Testing and Materials.
Zirconium for Nuclear Primary Steam Systems
Authors: Webster RT
Published: March 2009

Zirconium and zirconium alloys provide the best combination of metallurgical and mechanical properties for light and heavy water nuclear reactor fuel cladding and for the primary steam generation equipment. However, before materials may be used in such applications, long-term mechanical properties within the reactor operating temperature range must be established. Also, fabrication methods for such systems must be developed and evaluated.

In order that zirconium would become a qualified ASME Boiler Code material, a long-term test program was initiated; the qualifying data is presented in graphical form. The statistical data on short-term physical tests is amplified by the long-term creep rate and rupture-life versus temperature data.

Primary steam generation equipment fabrication data and criteria are presented with examples. Examples of the use of zirconium and zirconium alloys in nuclear and non-nuclear structures is reported; the stages necessary to fabricate components for the large nuclear steam generation equipment used in commercial power production is discussed.

Additional data required by international specifications is also presented, including charpy impact and fatigue data, as well as the normal mechanical property tests.
Development of a Closed-End Burst Test Procedure for Zircaloy Tubing
Authors: Hardy DG , Stewart JR , Lowe AL
Published: March 2009

The results of a round robin on the closed-end burst testing of Zircaloy tubes for fuel cladding are presented. Sponsored by the American Society for Testing and Materials, the testing program had as its objective the preparation of a suitable burst test procedure for inclusion in the ASTM Specification for Wrought Zirconium and Zirconium Alloy Seamless and Welded Tubes for Nuclear Service (B 353-71).

Seventy-five specimens, cut from five lengths of tubing were tested at room temperature. Four laboratories took part and six different test methods were used.

It was found that the closed-end burst test can be used to characterize the biaxial mechanical properties of Zircaloy cladding tubes. The tests identified certain parameters as having a significant effect on the mechanical properties and which must be precisely defined in the specification, these include the internal mandrel geometry, strain rate, and system stored energy. The most desirable burst test apparatus is one which has low stored energy and which provides good control over the volume pumping rate producing a smooth pressure versus fluid volume output curve.
Uniform Ultrasonic Inspection of Fuel Sheath Tubing
Authors: Cross BT , Abbott DJ
Published: March 2009

Ultrasonic nondestructive inspection of fuel tubing can be made far more uniform and reliable by placing proper priority on the various test parameters. Search units, for example, should be designed specifically for a given tube size, tube material, and quality assurance specification. It is common practice to select a standard product line search unit and juggle test parameters until some semblance of a test is achieved. Through an in-depth study of tubing inspection requirements, it has become evident that arbitrarily selected search units will rarely satisfy the actual requirements for tubing inspection.

“Spectral compatibility” in an ultrasonic inspection system is as important in achieving realistic test results as proper selection of search units. This often ignored parameter is one of the keys to uniform reproducible inspection results.

This paper discusses these significant test parameters, how they are used, and their relation to the current ultrasonic inspection procedures being used in American Society for Testing and Materials Committee B-10 on Reactive and Refractory Metals and Alloys.
Improved Metallography of Zirconium Alloys
Authors: Kaufmann PD , Danielson P , Baroch EF
Published: March 2009

Several procedures for the metallographic preparation and viewing of zirconium alloys have been developed in recent years which broaden the ability of the metallographer to more totally describe the morphology of these materials. For most detailed studies, it is not possible to describe with a single method the structure of commercial materials. Features found to be present by one technique may be completely missed or inconclusively revealed by other techniques.

Anodizing a metallographically prepared sample of a zirconium alloy in a phosphoric acid solution results in color contrast between retained intermetallic compounds and the matrix. While this method is not new, its application to evaluation of low-solubility compounds is described herein. A color contrast is also observed between various types of intermetallic compounds by the nature of their different anodizing characteristics. A technique for metallographic preparation and anodizing is described. The resultant microstructure with typical carbide, phosphide, and silicide intermetallics in zirconium and zirconium alloys is shown with color photomicrographs. Characteristics of each of these three types of intermetallic compounds are described.

A technique for heat tinting metallographic samples of Zircaloy-2 and Zircaloy-4 to show alloy microsegregation is also described. This method is complementary to anodizing and conventional etching methods. Subtle compositional variations, such as the tin distribution in the Zircaloys, can be revealed by heat tinting techniques. Such variations are not apparent with other techniques.
Determination of Solid Solubility Limit of Hydrogen in Alpha Zirconium by Internal Friction Measurements
Authors: Mishra S , Asundi MK
Published: March 2009

The general background internal friction variation with temperature is considered to be due to the oscillations of the dislocation segments in metal crystals. When these segments are strongly pinned by impurities or precipitates, then the back-ground level reduces considerably. Under certain experimental conditions, zirconium hydride precipitates along the dislocations so as to pin the dislocation segments firmly. For a given composition of Zr-H alloy, the maximum temperature at which there is a measurable decrease in internal friction, due to precipitation, indicates the maximum solubility at that temperature. Thus, the solid solubility of hydrogen in iodide zirconium can be determined by a close study of the precipitation of hydride using the internal friction technique. Such a technique has been used to determine the solubility limit of hydrogen in iodide zirconium, Zr-0.25Gd and reactor grade sponge zirconium in the temperature range of 100 to 300°C. However, in the latter case the technique was found to be inadequate.
Potential for Improvement of Mechanical Properties in Zircaloy Cold-Rolled Strip and Sheet
Authors: Kaufmann PD , Baroch EF
Published: March 2009

A summary of mechanical properties representing several thousand Zircaloy-4 channel blanks is presented. The data show a wide variation in elevated-temperature mechanical properties.

Investigation of the effect of variations in ingot chemistry on mechanical properties is discussed. The effect of the elements carbon, silicon, tin, and oxygen on elevated-temperature yield strength is statistically significant, but does not account for the total magnitude of the variation in mechanical properties observed. Although it does not represent an actual material variation, tensile testing strain rate was found to have a very significant effect on elevated-temperature yield strength values. Further experimental work was performed to investigate the effect of fabrication variables on elevated-temperature yield strength. The most influential processing parameter on elevated-temperature yield strength of the resultant product was the hot-rolling temperature. A 20 to 30 percent variation in yield strength was observed between alpha-rolled and beta-rolled material. This variation existed even after subsequent cold rolling and recrystallization. The primary difference between these two products was shown to be the difference in preferred orientation. The elevated-temperature transverse yield strength and bend ductility were improved by beta rolling, while the product uniformity, corrosion resistance, and tensile elongation were decreased. The limitations as well as potential improvements in mechanical properties which could be obtained through processing variations are discussed.
Operable Deformation Systems and Mechanical Behavior of Textured Zircaloy Tubing
Authors: Tenckhoff E
Published: March 2009

The slip and twinning systems known to operate in zirconium and Zircaloy are discussed with respect to the mechanical behavior of Zircaloy tubes. For extreme basal pole orientations in the radial and tangential directions, different stress-strain conditions in the tube cause different deformation systems to operate. The effects of the stress-strain conditions are discussed for axial tension and compression, internal and external pressure, axial bending, tube collapse, and axial torsion. The predictions of short time properties for strongly textured radial and tangential tubing are compared with experimental results.

The method of taking tubes from a textured plate has proved suitable for studying texture as a parameter not only in the extreme positions discussed here but also at intermediate positions. This technique guarantees that other parameters, such as the degree of deformation and recrystallization, grain size, segregation, etc., are constant since all the variants of texture are present in one single tube.
Directionality of the Grain Boundary Hydride in Zircaloy-2
Authors: Kawanishi H , Ishino S , Mishima Y
Published: March 2009

The correlation between hydride orientation and texture has been studjed. Previous_work showed that there are grain boundary “habits” such as {101¯1}, {101¯3}, and {101¯5} for hydride precipitation in Zircaloy-2. By taking into account the stereographic configuration of these habits, the fn-values of various specimens have been evaluated. Comparison between fn-values obtained metallographically and by the present method gives excellent agreement.

The mechanism of stress reorientation of hydride and the dependence of stress reorientation on stress direction are also discussed.
Mechanisms of Irradiation Creep in Zirconium-Base Alloys
Authors: Dollins CC , Nichols FA
Published: March 2009

Many models have been proposed to explain and predict in-pile creep of cladding materials. Our purpose is to consider the relative merits of models based on diffusion of irradiation-induced point defects and to apply those models to zirconium-base alloys. At intermediate stresses, creep is believed to be due to dislocation glide between irradiation-produced obstacles and controlled by climb over those obstacles. The two primary models to predict dislocation climb are based on (1) the alleged increased attraction dislocations have for interstitials over vacancies and (2) statistical fluctuations in the arrival rate of vacancies and interstitials produced in equal numbers. Both models are considered in detail. In addition to creep caused by edge dislocation glide and climb, creep due to preferred nucleation of dislocation loops and their subsequent growth is considered. Such creep is believed to be dominant at low stresses.
High Deformation Creep Behavior of 0.6-in.-Diameter Zirconium Alloy Tubes Under Irradiation
Authors: Wood DS
Published: March 2009

High creep strain experiments have been carried out under irradiation using cold worked Zircaloy-2, cold-worked Zr-Nb, and heat treated Zr-Nb 0.6-in.-diameter tubes in DFR, DMTR, and PLUTO reactor. The tests in PLUTO were found to be the most useful since full creep curves were obtained using neutron radiography techniques. Creep strains of up to 9 percent were obtained on cold-worked Zircaloy-2 tubes without failure, thus substantiating the recommended pressure tube creep strain limit of 3 percent. Up to 5 percent creep strain was observed with cold-worked Zr-Nb tubing, but since one tube failed at only 1.8 percent strain it is not yet possible to specify a realistic yet safe creep limit for this material.
Suppression of Void Formation in Zirconium
Authors: Yoo MH
Published: March 2009

An analysis is given of the effects of anisotropic thermal expansion coefficients and elastic constants on radiation-induced void formation in zirconium and other hexagonal metals. Upper bound values of thermal stress in polycrystalline metals are estimated. A cyclic temperature fluctuation at high irradiation temperature causes changes in internal stresses that suppress nucleation and growth of voids as a result of the enhanced recombination of point defects at grain boundaries and also retard void growth due to the induced self stress field. Such effects are more pronounced in highly anisotropic zirconium than in magnesium. Effects of hydrostatic pressure on void formation are also investigated. Other metallurgical variables for void formation are discussed, and an experiment to test the current concept is suggested.
Deformation of Irradiated Zirconium-Niobium Alloys
Authors: Ells CE
Published: March 2009

This review summarizes the flow and fracture behavior of irradiated zirconium-niobium alloys. It is confined to the alloys currently used in power reactors, namely Zr-1.ONb, Zr-2.5Nb, and Zr-2.5Nb-0.5Cu, and of these, most of the literature deals with the Zr-2.5Nb alloy. Both before and after irradiation, the Zr-2.5Nb alloy has a good combination of strength and ductility; these properties have enabled reactor designers to replace Zircaloy with Zr-2.5Nb in applications where the superior in-reactor creep resistance of the latter alloy is important. The good ductility of the irradiated Zr-2.5Nb alloy, however, is dependent on the alloy remaining below the beta transus in the final stages of heat-treatment/fabrication before irradiation. Although there is much information on the deformation of the irradiated material relevant to reactor design, the basic understanding of the deformation is in an early stage of development.
Variation of Zircaloy Fracture Toughness in Irradiation
Authors: Walker TJ , Kass JN
Published: March 2009

Irradiated and unirradiated fracture toughness data for Zircaloy-4 are summarized as functions of both temperature and orientation. Data are presented as ASTM “valid” values and as maximum or failure values which may be desirable for certain applications with multiple redundant structures. Surface fractographic characterization is included based on scanning electron microscope studies of the fracture surface and metallographic studies of sections of the crack tip region. A limited amount of crack growth data for irradiated material was obtained from the irradiated fracture specimens prior to fracture testing and has been included for general reference.
Plastic Instability in Irradiated Zr-Sn and Zr-Nb Alloys
Authors: Cheadle BA , Ellis CE , van der Kuur J
Published: March 2009

Factors affecting the plastic instability of irradiated zirconium alloys in tensile deformation have been studied. The materials used were pure zirconium, commercial Zircaloy-2 and Zr-2.5Nb, and a series of alloys based on pure zirconium containing either niobium or tin. The materials were rolled into thick sheet which enabled different crystallographic textures and deformation modes to be studied. Niobium alloy additions delay the onset of plastic instability and in some circumstances reverse the textural effects found in commercial Zircaloy-2 and Zr-2.5Nb. The merits of Zr-Nb alloys for use as fuel sheathing are outlined.
Assessment of Fracture Studies on Zircaloy-2 Pressure Tubes
Authors: Pickles BW , Cowan A , Johnson ER
Published: March 2009

It is shown that, to initiate an unstable fast fracture during operation of Zircaloy-2 pressure tubes used in the Steam Generating Heavy Water Reactor, a defect more than 4 in. long and having a depth 80 percent through the wall has to be present. The effect of hydrides oriented in both the circumferential and radial directions is discussed, and it is concluded that the hydrogen absorbed during a 30 year life should have no significant effect on the critical defect size. Similarly, it is shown that fast neutron damage will not have a deleterious effect on the critical defect size. The growth of partial thickness defects due to pressure cycling is discussed in relation to the types of defects which could be present in pressure tube or could form during operation. Overpressure tests before and during the operational life of the reactor are analysed, and the use of periodic cold pressure tests is considered as a means of demonstrating pressure tube integrity.
Stress Corrosion Cracking of Zircaloys in Iodine Containing Environments
Authors: Cox B
Published: March 2009

Iodine solutions in organic solvents fall into two groups. First, those which, like iodine vapor at room temperature, cause crack propagation in double cantilever beam (DCB) specimens but do not initiate cracks in smooth specimens. These are solvents which form no, or only weak complexes with iodine. A second group of solvents (alcohols) both initiate cracking in smooth specimens and cause crack propagation in DCB specimens. These are solvents which form strong complexes with iodine. In addition to these two groups there are a few solvents in which neither crack propagation in DCB specimens nor cracking of smooth specimens occur.

Modifications to the chemistry of the system by additives were effective only for arsenite and N2O additions to alcoholic solvents. In both instances times to failure were increased. These results are discussed in terms of the chemistry of the system, and the mechanisms operating during both crack initiation and propagation are considered.
Effect of Surface Treatment on the Irradiation Enhancement of Corrosion of Zircaloy-2 in HBWR
Authors: Lunde L , Videm K
Published: March 2009

Specimens of Zircaloy-2 have been exposed at 240°C (464°F) in various locations in the primary circuit of the Halden Boiling Water Reactor (HBWR). Corrosion data have also been collected from Zircaloy-2 clad fuel elements. The radiation field caused a drastic enhancement of the attack, corrosion rates increased a hundred times, and was under normal conditions about 0.15 mg/dm2 per day for pickled, anodized, and autoclaved material. Variations in the flux level from 2 × 109 to 3 × 1012 neutrons (n)/cm2 ⋅ s (> 1 MeV) had little influence on the corrosion rate, and it is suggested that γ-irradiation or lower energy neutrons, rather than fast neutrons, can be responsible for the corrosion enhancement. When uranium was present in the water, the corrosion rate increased for pickled and for autoclaved fuel rods, while hardly any effect was observed with anodized material. A deliberate fluoride contamination on the specimens increased the corrosion rate in-pile as well as out-of-pile. By anodizing this harmful effect of fluorides could be completely counteracted.
Interpretation of Plate Loading Test Results
Authors: Dodds DJ
Published: March 2009

Many varieties of the plate loading test have been developed to aid in the design of underground powerhouses, major tunnel projects, and foundation design of large concrete dams. Whereas all forms of the test dutifully generate data, generally the only results of these data are the modulus of deformation and, on occasion, some creep information. However, much significant information is ignored, such as: strength parameters, in situ stress levels, amounts of stress and blast damage, plus judgment factors on elastic-plastic response. Information on all these items is not available from every test, but some information occurs often enough to be of significant value and should be used together with the creep and modulus values.
A Radio Frequency Warning Device for Early Roof Failure Detection
Authors: McVey JR , Meyer TO , Lewis SR
Published: March 2009

A radio frequency roof failure warning device has been designed by the Bureau of Mines, Spokane Mining Research Center, that can be easily installed in a standard rockbolt hole drilled into a mine roof or rib. The device will monitor deformation of the exposed rock surface with respect to an anchor installed in the rock at any reasonable depth. It provides surveillance for falling rock and, with modification, will measure rock movement as a function of time. The device is inexpensive, coal mine permissible, and of nonobstructing nature when installed, thereby lessening interference with mining operations. A warning signal is transmitted to a radio receiver in the immediate area when the deformation limit (adjustable from 0 to 212 in.) is reached. Total cost for the roof failure sensor is expected to be less than $50 in large quantities and any standard radio receiver can be used. A small inexpensive personal receiver can be developed for mine personnel to use when working in the immediate area.
Measurement of In Situ Shear Strength Using the Torsional Shear Method
Authors: Sellers JB
Published: March 2009

The torsional shear test consists of applying a torque to a cylindrical core of rock isolated from a rock mass, by means of a diamond drill. The core is restrained by means of an axial rock bolt which is used to apply a controlled normal load. The core is gripped in an apparatus and twisted with a known torque. The twist is measured and the point of failure determined. Failure occurs on a well-defined plane, which can be made to coincide with indigenous planes of weakness. Test results give the shear strength directly in terms of the cohesion and the angle of friction. Residual shear strength after prolonged sliding can also be determined.
A Simple Method for Estimating In Situ Stresses at Great Depths
Authors: Haimson BC
Published: March 2009

A new borehole method has been recently suggested for estimating stresses remotely at long distances from the operator and under any stress configuration. This method, called “hydraulic fracturing,” is based on a technique used by the petroleum industry to stimulate oil wells. The basic required equipment is available commercially through renting or purchasing, and the experience of oil field service companies is accessible to ensure correct functioning. The method itself consists of pressurizing a sealed-off interval of the tested borehole until fracture occurs. Additional pumping is then undertaken to open and extend the fracture. After the pressure is released, an “impression packer” is used to obtain an oriented imprint of the hole showing the inclination and azimuth of the hydraulic fracture. Using the recorded fracturing pressures and the fracture impression, the principal stresses and their directions are calculated. Laboratory experimental work has confirmed most of the theoretical assumptions and results. Stresses calculated from field hydraulic fracturing tests have demonstrated the great potential of the method. In particular, a hydraulic fracturing test was conducted at 6280 ft (1915 m) below the surface at Rangely, Colo. The in situ stresses as determined by the method were in accord with the expected condition for the type and the slip direction of an existing fault, and were used to predict the critical pore pressure necessary to trigger local earthquakes. Following the successful experiment, more field tests have been planned, and a number of research groups have purchased the necessary equipment, planning to use hydrofracturing on a routine basis in the future.