bluuebunny/crossref_metadata_2025_split huggingface dataset:
Properties and Applications of Molybdenum
Authors: Burman R 
Published: December 2008

Molybdenum (“Moly”) is the most readily available and least expensive refractory metal. Massive ore reserves and many refinement facilities are located within the United States. The major application for Moly, over 80% of total markets, is that of alloy additions to irons and steels.
Metallic Moly is consolidated into commercial products by the powder-metallurgy process (P/M) and by the consumable electrode vacuum-arc casting process (VAC). Moly's high melting point and low vapor pressure at extreme temperatures justify its applications to cold wall vacuum or inert atmosphere furnace equipment. These properties, as well as Moly's high thermal conductivity and good electrical and chemical properties, lead to applications in glass-making manufacture of fibers and containers. Moly is also widely used in electronics, solid-state devices, X-ray tubes, crystal growing, heat pipes, photoetched masks, etc.
TZM Moly Alloy is the best commercial high strength, high temperature material for hot-work tool applications such as die casting (even ferrous metals), hot extrusion (non-ferrous and ferrous metals), hot piercing stainless steel tubes, isothermal forging tools, isothermal shape rolling, hot gas valves and seals, and hot turbine components. The Moly-30% tungsten alloy (Mo-30W) is commercially employed for its high melting temperature of 2829°C (5125°F) and its chemical inertness in corrosive molten zinc, especially the high purity grades. Moly and Moly-base alloys are commercially used for principally high temperature applications in hot equipment, hot working tools, and hot operating machines.
The Effect of Wafer Flatness on Yield by Off-Line Computer Simulation of the Photolithographic Process
Authors: Denes L 
Published: December 2008

This paper describes a powerful new computer program which has the ability to directly simulate virtually all popular projection and stepper type aligners. The effects on yield of such metrologies as global wafer retilting, exposure by exposure retilting and autofocusing will be analyzed. Three point and the new seven point mirror projection aligner image plate geometries will also be characterized.
The results of several process simulations will be presented using the new program's powerful graphic displays which yield a view of wafer shape never seen before.
Dopant Profiling in Silicon
Authors: Pawlik M 
Published: December 2008

The developments necessary to implement a comprehensive research programme aimed at understanding dopant incorporation in silicon are described. The two experimental techniques used, and possessing the required dynamic range and depth resolution, are high resolution Spreading Resistance and Secondary Ion Mass Spectrometry. Comparative studies of samples with both techniques lead to a greater understanding of dopant incorporation and dopant activation and provide a wealth of data for the refinement of process models such as SUPREM.
Data are presented on a number of different samples, including boron and arsenic implantations and anneals (furnace, and electron beam) in silicon and in silicon-on-sapphire.
New Applications of Tape Bonding for High Lead Count Devices
Authors: Marshall JF , Sheppard RP 
Published: December 2008

There are two primary forces which drive the interconnect market: the first is manufacturing cost, and the second is system performance. In the past, tape automated bonding (TAB) was viewed as an interconnection technology which offered a cost advantage; however, only a handful of semiconductor manufacturers with high volume, low lead count product lines were able to demonstrate a cost savings with TAB over conventional automatic wirebonding.
Recently, however, development work and usage of TAB has been accelerating due to performance considerations in the interconnection of increasingly complex VLSI devices. VHSIC speeds are forcing new approaches to packaging and interconnection. TAB offers a practical solution to many of these performance problems. TAB leads offer improved electrical, thermal and mechanical properties in addition to doubling the I/O density capability for perimeter pad configurations compared to conventional wirebonding. Furthermore, TAB technology affords the potential to accommodate I/O pads anywhere on the surface of the device through the use of a multilayer “area array” or “decal” tape interconnect pattern.
Recovery of Chromium from Plating Wastes
Authors: Bolto BA , Kotowski M , Pawlowski L 
Published: December 2008

Recovery of chromium from a plating sludge is discussed. The process consists of two parts: roasting the sludge with sodium carbonate (Na2CO3) and calcium oxide (CaO), followed by leaching. The optimal parameters for roasting are a temperature range of 950 to 1000°C and Na2CO3 and CaO contents of 2.4 and 2.8 mol per mole of chromium oxide (Cr2O3) respectively.
Demineralized water is recommended for the leaching of sodium chromate (Na2CrO4) from the agglomerate formed during roasting. The leached water is recycled through a strongly acidic cation exchanger followed by a weakly basic anion exchanger. A solution of chromate or chromic acid having a concentration up to 60 kg Cr/m3 is obtained.
Comparison of Analytical and Experimental Stress-Intensity Coefficients for Chevron V-Notched Three-Point Bend Specimens
Authors: Bar-On I , Tuler FR , Roman I 
Published: December 2008

Chevron-notched specimens in a number of configurations have been recently used to determine plane-strain fracture toughness. Most researchers have employed tensile short-rod and short-bar specimens, while the three-point bend configuration has been used only to a limited extent despite its convenience for testing at ambient and high temperatures.In the present study, both experimental and analytical K-calibrations for three-point bend chevron-notched specimens were carried out. Fracture toughness tests were performed in accordance with ASTM Standard of Test Method for Plane-Strain Fracture Toughness of Metallic Materials (E 399-81) to determine plane-strain fracture toughness, KIc, for polymethyl methacrylate (PMMA), 60/40 brass, 7075-T651 aluminum, and quenched and tempered 4140 steel. In parallel, three-point bend chevron-notched specimens of these materials were loaded to failure. The ratio (KIc/Pmax) B · √W is the dimensionless quantity Y*. This quantity was found to be 11.6 for the specimen geometry employed in the present study.Three analytical models, which have been used successfully for the short-bar and shor t-rod configurations were used to calculate the stress-intensity coefficient and the critical crack length for the three-point bend configuration. The predicted stress intensity coefficients are 20 to 60% higher than the experimental value, and the predicted critical crack length is at least 20% lower than the directly measured critical crack length.
Correlation of the Parameters of Fatigue Crack Growth with Plastic Zone Size and Fracture Micromechanisms in Vacuum and at Low Temperatures
Authors: Verkin BI , Grinberg NM , Serdyuk VA 
Published: December 2008

Much attention has been paid recently to the kinetics and micromechanisms of fatigue crack growth in various materials. Of particular interest are magnesium alloys, which find expanding applications in structures requiring high specific strength. This paper reports experimental results on Mg-Nd-Zr, Mg-Y-Cd, and Mg-Y-Cd-Zn alloys in different structural states. We measured the fatigue crack propagation rates and the values of the threshold point Kth, the transition points K1−2, K*, and K2−3, and the critical point Kfc in air at 293 K and in a vacuum of 10−4 Pa at 293 and 140 K. The plastic zone size around a fatigue crack was studied by X-ray diffraction and the micromechanisms of its growth by electron fractography.
Vacuum is shown to produce a decrease in the rate of fatigue crack growth in the whole range of Kmax values, while Kth and Kfc remain undergoing. The effect of vacuum was most prominent in thermally hardened alloys undergoing cyclic softening. A reduction in temperature from 293 to 140 K produced an increase in Kth and a decrease in the rate of fatigue crack growth in Region I and at the beginning of Region II for all alloys. In Region III, however, the rate of fatigue crack growth and Kfc changed ambiguously.
The plastic zone size was found to be larger in vacuum than in air; a reduction in temperature produced a decrease in its value regardless of the alloy structural state. The micromechanisms of fatigue crack growth were found to be dependent on composition and initial structural state of alloys, and variations in these parameters with low temperature correlated with the plastic zone size and the rate of fatigue crack growth. Our studies show the existence of certain structural and substructural criteria for the transition points K1−2, K*, and K2−3.
Fracture Behavior of SiC Matrix Composites Reinforced with Helical Tantalum Fiber
Authors: Kagawa Y , Nakata E , Yoshida S 
Published: December 2008

The present study was started to examine the effect of ductile metallic fiber on the toughness and fracture behavior of engineering ceramics. Helical fibers were used for the purpose of better ensuring stress transfer from the matrix to the fiber than straight fibers.
A length of tantalum fiber 0.4 mm in diameter was formed into two types of helix. Helical or straight fibers were incorporated in a silicon carbide (SiC) matrix. The fibers were unidirectionally aligned to the longest axis of a specimen with uniform spacings. Specimen dimensions were 10 by 10 by 55 mm. Specimens were prepared by means of vacuum sintering. The volume fraction of the fiber was varied from 0.01 to 0.04. Three-point bending tests were carried out at room temperature in air. Measurement of the acoustic emission signal was made to investigate the fracture process of the composites. Results were compared with three kinds of specimens: helical fiber reinforced composites, straight fiber reinforced composites, and SiC matrix alone.
It was found that the fracture of the composites reinforced with tantalum fiber, whether straight or helical, was not so catastrophic as to be shattered to pieces like that of the SiC matrix alone. This arises because in fiber reinforced composites, fibers bridge the crack surfaces which have occurred in the matrix and carry the load which the matrix supported before fracture. But the fracture behavior of both types of composites differs in detail depending on their fiber geometry. The maximum load supported by the specimen after the matrix fracture was larger in the helical fiber composites than in the straight fiber composites. This seems to be due to the fact that the stress-transfer effect between the matrix and fiber was better for the helical fiber composites than for the straight fiber composites. Also, multiple fracture of the SiC matrix was observed in the helical fiber composites. Moreover, the total work done up to the complete fracture of a specimen, which was estimated from the load-displacement relation, was different by the fiber geometry and this was due to the differences of the energy absorption mechanism of the composites.
Fatigue Response of Notched Graphite/Epoxy Laminates
Authors: Kress GR , Stinchcomb WW 
Published: December 2008

Although composites have gained widespread use, we do not, as yet, have a precise and complete understanding of the mechanisms of damage development in composite materials. Recent research results have pointed out the need to treat damage as a collective condition—that is, a damage state, rather than as an assembly of discrete and independent damage modes. This paper presents the results of an investigation to determine the damage states which develop in two quasi-isotropic graphite/epoxy laminates with center holes due to tension-tension cyclic loads, to determine the influence of stacking sequence on the initiation and interaction of damage modes and the process of damage development, and to establish the relationships between the damage states and the strength, stiffness, and life of the laminates. Damage was monitored nondestructively throughout the loading history using X-ray radiography, moiré interferometry, and stiffness change. Some specimens were deplied after specific numbers of cycles to determine the distribution of damage in each ply around the hole and to confirm the components and size of the damage state observed nondestructively. Fatigue life and residual strength tests were also performed.
Fatigue damage in the two laminates included matrix cracks in all plies followed by delaminations. The density of matrix cracks and the distribution of the damage zone (matrix cracks plus delaminations) in laminates cycled at the same percent of notched tensile strength were strongly dependent on the local constraint and distribution of interlaminar stresses as governed by the stacking sequence. The distinctly different damage states which developed in the two initially quasi-isotropic laminates due to similar load histories produced stiffness changes of 15% to 20%, different rates of change in residual strength (an initial increase followed by a decrease), and a factor of two to four difference in fatigue life.
Finite-Element Analysis of Interlaminar Shear Stress Due to Local Impact
Authors: Ross CA , Malvern LE , Sierakowski RL , Takeda N 
Published: December 2008

Interlaminar delamination may occur as a result of a nonperforating low-velocity impact of a foreign object against a continuous-fiber composite laminate. Experimental evidence shows that for a crossplied laminate consisting of three lamina and subjected to a central localized impact, one delamination region will extend farther from the impact point than the second region.
To establish a quantitative value for the interlaminar shear stress of a crossplied fibrous composite plate subjected to a central impact, a finite-element computer program has been utilized. Specifically, a three-dimensional dynamic-elastic-orthotropic-material finite-element program has been used in which the interlaminar shear stress can be calculated directly. This program was used to evaluate the interlaminar shear stresses for a [05/905/05] glass/epoxy plate with built-in edges, and subjected to a load simulating a central localized impact of 45.7 m/s by a cylindrical steel projectile.
Results of the calculations show a region of large shear stress (exceeding the estimated shear strength of the matrix material) extending from the impact point toward the boundary in the 0-deg direction while a region of large shear stress in the transverse 90-deg direction was found to be much smaller. Also, only minor differences in calculated shear stresses were evident in the interlaminar plane immediately below the impact point when compared with the interlaminar plane farthest from the impact point. The high-shear-stress regions agreed qualitatively with the areas observed in experiments.
Toward Process Optimization by Monitoring the Electrical Properties During the Cure Cycle for CFRP
Authors: Minoda Y , Sakatani Y , Yamaguchi Y , Niizeki M , Saigoku H 
Published: December 2008

Application of advanced composite materials, namely carbon fiber reinforced plastic (CFRP) (graphite/epoxy) to aerospace structures is currently expanding from simple components to complex-shape integrated structures. The objective of this study is to establish the feasibility of optimizing the cure cycle of integrated CFRP structure by in-process direct measurement of electrical properties of the article in an autoclave.
An instrumentation technique that included material and shape of electrodes and an insulator and bleeder system was investigated. Experimental studies using the above test setup attempted to determine correct pressurization timing under certain preprogrammed heating patterns thus resulting in cured CFRP laminates, which were practically voidless, with proper fiber volume fraction and thickness per ply.
Work of Fracture in Metal Matrix Composites
Authors: Daimaru A , Hata T , Taya M 
Published: December 2008

When one talks about “fracture toughness” of composites, one must be careful in distinguishing the energy release rate for the initiation of a crack (γI) and the energy absorbed during the fracture averaged over the whole history of fracture process (γF). Unlike metals, the value of the critical stress intensity factor KIc of composite was found not to reflect any basic material property. Instead, the measurement of γF seems to represent a meaningful toughness property of composite when the composite is a mixture of brittle and ductile phases, such as metal matrix composites (MMCs).
We have recently conducted experimental and analytical study on the value of γF of unidirectional fiber MMC and obtained a good agreement between the experiment and theory. In this paper, we report the experimental and theoretical results on a particulate MMC. The results of two different types of MMCs have revealed that three-point bending test of the MMC specimen with center notch can be used as a reasonable method to measure γF.
Liquid Crystal Film Visualization Approach to Fracture in Composites
Authors: Kobayashi A , Suemasu H 
Published: December 2008

The cholesteric liquid crystals indicate a change of color in response to the temperature change by reflecting the specified wavelength of light due to the pitch alternation caused by the temperature change in the molecular layer of a liquid crystal, indicating red at lower temperature and blue at higher temperature.
Using these liquid crystals, heat evolution during rapid crack propagation can be estimated. However, rather much errors have been introduced due to poor response of liquid crystals.
In the present study, the heat evolution produced during rapid fracture in composites will be calculated through the improved dual-layer liquid crystal film method, which is to improve the response and to increase the accuracy in measurement of isothermal colored boundaries appeared in the liquid crystal film during fracture by obtaining two isothermals, T1 and T2, necessary for heat evolution calculation, at an earlier period of time after fracture, and by making the spacing between isothermals larger, leading toward the easier discrimination of colored boundaries, resulting in fewer errors. The results show that the time required to obtain two isothermals is reduced even by 50% for the glass-fiber composites. A videotape recorder system is used to record the colored isothermals, and velocity gages to measure the crack propagation velocity.
Thus obtained heat evolution is correlated with the crack propagation velocity.
Shear Modulus of Epoxy Resin Under Compression
Authors: Hayashi T 
Published: December 2008

The matrix shear modulus of a unidirectionally fiber-reinforced composite material is one of the factors affecting its compressive shear mode fracture and it depends on the compressive stress.
In order to investigate the effect of compressive stress on the shear modulus, a special form of test specimen was designed such that compressive and torsional loads could be applied simultaneously. Test specimens were molded from epoxy resin for structural use.
Under every constant compressive load, specimens were subjected to torsional moment, and the corresponding strains were measured from which shear strains were calculated. Then the shear modulus was obtained as a function of compressive stress.
It was found that the shear modulus of epoxy resin decreased with increasing compressive stress in the range beyond the proportional limit, and the order of magnitude of its reduction was found.
Evaluation of Factors Affecting Tank Mix Compatibility of Pesticide Combinations
Authors: Brenner WE , Brown LJ , Machado IE 
Published: December 2008

Laboratory tank mix compatibility testing presents the challenge of predicting the ultimate physical fate of mixtures under a large variety of often poorly known field use conditions. Most procedures, as dictated by practical necessity, involve only a few test conditions, are easy to perform, and utilize common laboratory equipment. By reason of their simplicity, however, these tests may fail to adequately mimic, hold fixed, or consider many of the field variables which may influence compatibility.
Studies were conducted with two formulations of each of two pesticides to explore the effects of some of the variables generally known or perceived to affect formulation performance and physical compatibility. Fractional factorial experimental designs were conducted in stages to study the effects and interactions of water hardness, temperature, copesticide ratio, order of addition, degree of agitation, residence time of the mix in the tank, and dilution rate. For one of the formulation pairs multiple regression and analysis of variance were used to construct a model which was able to adequately predict the failure or success of experiments not yet performed. The results indicate that all these factors can affect tank mix compatibility. Complex interactions between the factors were observed. The effects and interactions of the factors appeared to vary both qualitatively and quantitatively from the other formulation pairs, indicating that the major effects and critical ranges of factors are different for different tank mixes. These results indicate the types of difficulties which can be expected to be encountered in devising simple standardized tests for tank mix compatibility.
The Reversing D-C Electrical Potential Method
Authors: Catlin WR , Lord DC , Prater TA , Coffin LF 
Published: December 2008

An automated reversing d-c potential system capable of measuring crack growth rates in compact-type, edge-notched, and surface-defected specimens under a wide variety of environmental conditions is described. Measurements can be made with ease during cyclic or static loading conditions. The unique characteristics of the system software, which give the operator a wide choice of test routines, including constant load range, constant stress-intensity range, and programmed load range or programmed stress-intensity range, are discussed. Detailed procedures are then given for conducting a “controlled K” cyclic test on a surface-defected specimen.
The system has outstanding stability and sensitivity. The high frequency of measurement permits averaging of many readings within a given cycle to obtain a single data point or to detail a given cycle. Techniques for averaging data to enhance the resolution of growth rate measurements are discussed.
Finally, results from several tests are described to demonstrate the versatility of the system in making measurements on different specimen geometries over a wide range of testing conditions.
Automated Test Methods for Fatigue Crack Growth and Fracture Toughness Tests on Irradiated Stainless Steels at High Temperature
Authors: Tjoa GL , van den Broek FP , Schaap BAJ 
Published: December 2008

An automated system for fatigue crack growth and fracture toughness measurements has been developed for irradiated stainless steels tested at temperatures up to 925 K. The system, including a microcomputer, is based on the d-c potential-drop technique for crack extension measurements. Specimens of the compact-tension type are used for the experiments. A description is given of the potential-drop method and the automated data acquisition system. The method of collecting N-a data pairs is given as well as the calculation and analysis of the fatigue crack growth rate (da/dN) and stress-intensity factor (ΔK). The measurement of load, deflection, and crack extension data to determine the J-versus-Δa curves is also discussed.
Calculations and interpretations of the results are in good agreement with the ASTM standards.
The system for crack growth experiments has proven to be very reliable, with a high resolution and accuracy.
In practice, good experience has been gained using the system for testing irradiated specimens under remote handling conditions.