Cu-Be Alloy Research Articles

Dissolution of beryllium in artificial lung alveolar macrophage phagolysosomal fluid

Dissolution of a lung burden of poorly soluble beryllium particles is hypothesized to be necessary for development of chronic beryllium lung disease (CBD) in humans. As such, particle dissolution rate must be sufficient to activate the lung immune response and dissolution lifetime sufficient to maintain chronic inflammation for months to years to support development of disease. The purpose of this research was to investigate the hypothesis that poorly soluble beryllium compounds release ions via dissolution in lung fluid. Dissolution kinetics of 17 poorly soluble particulate beryllium materials that span extraction through ceramics machining (ores, hydroxide, metal, copper–beryllium [CuBe] fume, oxides) and three CuBe alloy reference materials (chips, solid block) were measured over 31 d using artificial lung alveolar macrophage phagolysosomal fluid (pH 4.5). Differences in beryllium-containing particle physicochemical properties translated into differences in dissolution rates and lifetimes in artificial phagolysosomal fluid. Among all materials, dissolution rate constant values ranged from 10 −5 to 10 −10 g cm −2 d −1 and half-times ranged from tens to thousands of days. The presence of magnesium trisilicate in some beryllium oxide materials may have slowed dissolution rates. Materials associated with elevated prevalence of CBD had faster beryllium dissolution rates [10 −7–10 −8 g cm −2 d −1] than materials not associated with elevated prevalence ( p < 0.05).

Mechanical and Electrical Properties of Rapidly Solidified Cu-Zr-Ag Alloy Fabricated by Powder Rolling Process

ABSTRACTA non-equilibrium Cu-Zr-Ag alloy was designed for the development of an alternative electric connector to Cu-Be alloys. This work aims at producing a Cu-Zr-Ag sheet using a hot-powder-rolling (HPR) process. The sheets were produced by a sequential process of HPR, pre-annealing, and cold rolling, using Cu93.5Zr5.5Ag1 (at.%) alloy powder produced by an argon gas atomization method. The Cu93.5Zr5.5Ag1 alloy sheet has a tensile strength of 1188 MPa and a conductivity of 33.2% IACS, which are similar values to those of Cu-Be alloys. In this paper, we optimize the conditions of the HPR process and reveal the correlation between the microstructure and properties of the Cu-Zr-Ag sheet produced by the HPR process. In addition, we discuss the alloy’s applicability for use as a connecter material.

Small-angle neutron scattering study of the magnetoplastic effect in the beryllium bronze aged in magnetic fields

The magnetoplastic effect induced in the beryllium bronze BrB-2 aged in magnetic fields of up to 1 T has been studied using the microhardness method. “Positive” and “negative” magnetoplastic effects have been shown to exist. The possibility of applying the small-angle polarized-neutron scattering method to the investigation of the effect of a magnetic field on the kinetics of phase formation in Cu-Be alloys has been analyzed. Models of the structure of possible scattering centers have been proposed.

Effects of Alloying Element and Heat Treatment on Properties of Cu-Ti Alloys

Cu-Ti alloys with titanium in the range of 0.5-6.0 wt% were developed to evaluate the effect of the titanium content and heat treatment on microstructure, hardness, and electrical conductivity. The hardness of the Ti-added copper alloys generally increased with the increase in titanium content and hardening was effective up to the 2.5 wt%-Ti addition. Microstructural examination showed that the second phase of <TEX>$Cu_4Ti$</TEX> started to precipitate out from the 3.0 wt% Ti-addition, and the precipitate size and volume fraction increased with further Ti addition. Aging of the present Cu-Ti alloys at <TEX>$450^{\circ}C$</TEX> for 1 h increased the hardness; however, the further aging up to 10 h did not much change the hardness. In the present study, it was inferred that in optimal Ti addition and aging condition Cu-Ti alloy could have the hardness and electrical conductivity values which are comparable to those of commercial Cu-Be alloy.

Magnetic Anisotropy of Nanocrystalline HITPERM-Type Alloys and its Correlation with Application

Structure as well as magnetic and magnetoelastic properties of nanocrystalline (Fe,Co)-(Hf,Zr)-Cu-B alloys (HITPERM-type) were investigated in order to find out which factors are responsible for the magnetic hardening of these magnetically soft materials. Magnetoelastic anisotropy, caused by the presence of cobalt, was found to play the predominant role in the observed increase of coercive field. On this basis, guidelines on chemical composition and crystallisation process selection were suggested for two fields of application: soft magnetic cores and sensors or actuators cores.

Cu-Be合金におけるトリチウムの吸着・溶解挙動［_I_］

Cu-Be合金におけるトリチウムの吸着・溶解挙動［_I_］

Surface Roughness of Cu-Be Alloy (C17200) Rod Alloy Produced by Horizontal Type Continuous Casting Process

Cu-Be alloy (C17200) rod having diameter of 23.5mm was produced by a vacuum continuous casting method at furnace temperature range of from 1240°C to 1260°C with casting speed range of from 35mm/min to 103mm/min. When the furnace temperature was 1240°C and 1250°C, Cu-Be alloy rod without fracture could successfully produced at high casting speed of 103mm/min. However, when the furnace temperature was 1260°C, the breakout occurred at casting speed faster than 78mm/min. Surface roughness (Ra) increased with increasing not only a furnace temperature but also a casting speed.

Transmission Electron Microscopy Observations on Cu-Mg Alloy Systems

Environmentally friendly Cu-based alloys with high strength and low electrical resistivity have been much sought in order to replace deleterious Cu-Be alloys for electrical applications. As one of the candidate systems, we have examined age-hardening behaviors of Cu-Mg alloys by using transmission electron microscopy (TEM). Cu-2.26wt.%Mg alloys were solution-treated and annealed at 723K, and their structural changes have been investigated. The Vickers hardness measurements showed that they aged-harden gradually. Our TEM observations showed that annealing for 6h brings about precipitation of numerous needle-like particles of 10 nm in length. The diffraction studies indicated these precipitates consist of the Cu2Mg phase with {111}Cu habit planes. When annealed for 96h, these precipitates become semi-coherent, which was manifested by moiré fringes; while maintaining the orientation relationship of (111)Cu//(111)Cu2Mg, [110]Cu//[110]Cu2Mg.

Effect of prior cold work on age hardening of Cu-4Ti-1Cd alloy

This research is part of a project whose scope was to develop high strength ternary alloys based on Cu-Ti system with the primary aim of substituting them for toxic and expensive Cu-Be alloys. In this pursuit, age hardening behaviour of Cu-4Ti-1Cd alloy has already been investigated and the present paper reports the investigations on the influence of prior cold work by rolling of 50, 75 and 90% on the age hardening of a Cu-4Ti-1Cd alloy using hardness and tensile tests and optical as well as transmission electron microscopy. As a result of cold work followed by aging, hardness of the alloy increased from 237 Hv in solution treated condition to 425 Hv on 90% cold work and peak aging. Similarly, yield and tensile strengths of the alloy reached maxima of 1037 and 1252 MPa respectively on 90% deformation and peak aging. The microstructure of the deformed alloy exhibited elongated grains and deformation bands. The maximum strength on peak aging was obtained due to precipitation of ordered, metastable and coherent βl, Cu4Ti phase in addition to high dislocation density and deformation twins. Both hardness and strength of the alloy decreased on overaging due to the formation of incoherent and equilibrium β, Cu3Ti phase. However, the morphology of the discontinuous precipitation was changed to globular shape due to large deformations and overaging.

Geometrical analysis and pattern recognition using mapping technologies of three-dimensional fracture surfaces in materials

Geometrical analysis of fracture surfaces in materials was made using newly developed computer programs on the three-dimensional images reconstructed by the stereo matching method. The global value of the fractal dimension of the fracture surface was estimated by the box-counting method on a fatigue fracture surface of a Cu-Be alloy and impact fracture surfaces of a SiC and an alumina. The results of the present analysis were well correlated with those of the two-dimensional fractal analysis. The fractal dimension map (FDM) by the box-counting method and the surface roughness map (SRM) proposed in this study can give important information about the local fracture mechanisms, the crack growth direction or the fracture origin in materials. FDM and SRM have interesting characteristics by which one can discriminate the flat regions, the regions of complex geometry or the steeply inclined areas on a given fracture surface. Pattern recognition using mapping technologies of FDM and SRM is also applicable to the extraction of “hidden patterns” on fracture surfaces, which cannot be observed only by microscopes.

SANDVIK 13RM19

Abstract Sandvik 13RM19 combines high mechanical strength with a nonmagnetic structure. This combination of properties has previously been found mainly in Co-Ni-base or Cu-Be alloys. The steel has very good corrosion resistance comparable to that of AISI Type 302. This datasheet provides information on composition, physical properties, elasticity, tensile properties, and shear and bend strength It also includes information on low temperature performance as well as forming, heat treating, and joining. Filing Code: SS-935. Producer or source: Sandvik Steel Company.

Fabrication and Properties of TiB&lt;sub&gt;2&lt;/sub&gt; Reinforced Cu Composites by Electromagnetic Stirring

Cu-Ti and Cu-B alloys were separately cast in vacuum arc melting furnace for alloying. These alloys were added to the copper melt of 1500K in the induction furnace and performed electromagnetic stirring at 1000rpm. The cast ingot(dia : 70mm, length : 100mm) was hot extruded with the extrusion ratio of 13:1 after heating at 1073K for 1 hour. The TiB 2 precipitates were observed in the extruded materials and the mean size of TiB 2 precipitates was found to be about 1.5µm. The volume fraction of TiB 2 varies due to the density difference between the TiB2 and the copper melt. With the increasing of TiB2 contents from 3 to 8 vol.%, the hardness and the tensile strength increased from 951 to 140Hv and from 248 to 278MPa, respectively, and the electrical conductivity decreased from 82 to 70%IACS. However, the mean size of TiB 2 particle was not increased despite increasing an annealing temperature.

Fractal Analysis of Three-dimensional Fracture Surfaces in Metals and Ceramics

Three-dimensional images of fracture surfaces formed by different mechanisms were reconstructed by the computer-aided stereo matching method on metals and ceramics. The fractal dimension of the three-dimensional fracture surface was estimated by the box-counting method using the height data generated by the stereo matching method. The ductile fracture surface (stage I fatigue) had the larger fractal dimension compared with the brittle-type fracture surface (stage II fatigue) in a Cu-Be alloy. However, it was difficult to classify the type of fracture, namely, ductile fracture or brittle-type fracture, in different materials only by the fractal dimension of the fracture surface, since even fractal dimensions of brittle-type fracture surfaces exhibited different values with different materials, depending on the fracture mechanisms of materials. There was a good correlation between the results of the three-dimensional fractal analysis and those of the two-dimensional fractal analysis on materials. The value of the fractal dimension of the three-dimensional fracture surface depends not only on the size of the analyzed area but also on the algorithms of the fractal analysis. The fractal dimension estimated in a given length scale range can be correlated with specific microstructures in materials.

An experimental study of the effect of hardening on plastic deformation at notch tips in metallic single crystals

Experiments to measure the effect of hardening on the plastic deformation field near a notch tip in metallic single crystals were conducted. The specimens were cut from pure Cu and a CuBe alloy (with 1.8–2.0 wt% Be) FCC single crystals. The Cu–2.0wt%Be alloy was selected because its initial hardness and rate of hardening can be modified by heat treatment. The Vickers hardness of the specimens ranged from 87 to 353 kg/mm 2 , while the hardening exponents ranged between 10 and 4.5. The experimental results were compared to analytical and numerical solutions from the literature. This comparison shows that the inclusion of elastic regions in the analytical solutions and anisotropic hardening in the numerical solutions results in better agreement with the experiments.

Quantitative Analysis of Three-dimensional Fatigue Fracture Surface Reconstructed by Stereo Matching Method

Three-dimensional geometry of a fatigue fracture surface in a Cu-Be alloy (the grain diameter is about 24 μm) was reconstructed by the stereo matching method based on the coarse-to-fine method. The fractal dimensions of the contours and of the fracture surface profiles extracted from the reconstructed image were then estimated by the box-counting method in the scale length range smaller than about one grain-boundary length (about 14 μm). The mean value of the fractal dimension of the contours was about 1.238, and was close to that of the actual fracture surface profiles in the plane in parallel with the crack growth direction (about 1.210) (in the parallel direction) and in the plane perpendicular to the crack growth direction (about 1.190) (in the perpendicular direction). Thus, the stereo matching method can reproduce the three-dimensional image of the complex fracture surface. However, the mean value of the fractal dimension of the reconstructed fracture surface profiles (about 1 128 in the parallel direction and about 1.146 in the perpendicular direction) was a little smaller than that of the actual fracture surface profiles, since there were microstructural features such as overhang, debris and microcracks on the fatigue fracture surface, which were only partly reproducible by the stereo matching method. Nevertheless, the geometrical information about a given fracture surface in a wide area can be obtained by the three-dimensional fracture surface reconstruction and analysis. Combination of three-dimensional and two-dimensional analyses may lead to the further understanding of the geometrical features of fracture surfaces and the fracture mechanism in materials. The fractal dimension was found to be a useful index not only for characterizing fracture surfaces but also for comparison of the result of three-dimensional image reconstruction with the actual fracture surface morphology.

プラスチック射出成形金型におけるＣｕ‐Ｂｅ合金インサート材形状の自動生成

Cu-Be alloy, whose thermal conductivity is 3 to 10 times higher than the common mold steels, has been identified as an effective material for improving the cooling uniformity of resin when applied it to plastic injection molds as inserts. However, arranging an optimum shape and size of the Cu-Be alloy into a mold is still one of the major problems in using this technology. In this paper, an evaluation method of cooling uniformity to a resin product is proposed by observing the temperature distribution and its variation on the resin surface. This method can be used for judging the validity of a cooling system inside an injection mold, such as the layout of cooling channels, or the shape and the arranging location of a embedded Cu-Be alloy block. This can be realized by comparing the result values gained from a defined evaluation function. Simultaneously, by making the evaluation value to converge to the minimum, a procedure is provided for the automatic search of the Cu-Be black from an arbitrarily assigned initial arrangement to the optimum shape. Furthermore, case studies are presented to discuss the process of realizing the automatic shape generation of Cu-Be alloy inserts based on numerical analysis.

Thermodynamic Analysis of Copper-Beryllium Alloy Production.

The thermodynamics of the Cu-Be-C-O system was studied in wide ranges of temperature and alloy composition, considering the importance of the minimization of Be2C and BeO formation in Cu-Be alloy production.The equilibrium relation of molten Cu-Be-C-O system was determined by conducting the following experiments: the solubility measurements of beryllium in molten copper under the conditions of Be2C-C equilibrium at 1,573 ∼ 1,873 K and under the conditions of BeO-C equilibrium for normalized CO partial pressure πCO = 0.01 and 1 at 1,423 ∼ 1,873 K. The activity coefficient of beryllium, γBe, in liquid Cu-Be alloys with respect to pure liquid beryllium as the standard state was also determined as a function of temperature T and mole fraction of beryllium XBe at 1,423 ∼ 1,873 K:ln γBe = {[-1 582.1 (T / K) -1-1.9154 log (T / K) + 7.1103] × 104 (±80)} · (1-XBe)2+ {[1 577.8 (T / K) -1 + 1.9154 log (T / K)-7.1089] × 104 (±80)}Additionally, the activity of beryllium in solid Cu-Be alloys was determined by an EMF method at 973 ∼ 1,073 K to establish a partial stability diagram of the solid Cu-Be-O system.Based on the results obtained, the operational conditions of the current Cu-Be alloy production process were also examined from a thermodynamic viewpoint. At the same time, several methods for improving the process were proposed.

Spontaneous deformation during aging under stress in a copper-beryllium alloy

An anomalous phenomenon has been found in a Cu-Be alloy during an investigation of the aging behavior. A platelike testpiece of a cold-rolled Cu-Be alloy (Japanese Industrial Standard No. C1720) was held at 1073 K for 2 hours, followed by quenching to solutionize. The testpiece was set in a hand-made cantilever jig and aged by applying an external stress with a screw at the free end of the cantilever. The free end of the cantilever leaves the screw in 30 minutes and warps further, within 1 hour, during aging. The spontaneous warping deflection is closely related to the hardness change through aging and is dependent upon the elastic strain introduced initially by the external load. Transmission electron microscope (TEM) observation makes clear that matastable γ′ precipitates, which bring about the most effective hardening and shrinkage, are predominant at the compression side of the cantilever, while extremely fine Guinier—Preston (G—P) zones are observed at an early stage of aging and coarse γ-phase precipitates are observed at a prolonged aging time in the tension side. The spontaneous warping results from the difference of the precipitation sequence between the two sides.

Measurement of the activity of boron in liquid copper using a four-phase equilibrium technique

The purpose of this article is to report measurements on dilute Cu-B alloys at 1723 K using a new four-phase equilibrium technique. The method can be considered as an extension of the conventional procedure involving metal-slag-gas equilibration, where the gas phase containing carbon monoxide is pre-equilibrated with graphite to define the carbon and oxygen chemical potentials. Under the reducing atmosphere, liquid diboron trioxide (B 2 O 3 ) is partially reduced by graphite generating a liquid Cu-B alloy and carbon monoxide at controlled pressure. After quenching to room temperature, the concentration of B in the liquid copper is measured. The equilibrium boron concentration in copper is measured as a function of the partial pressure of carbon monoxide in the gas phase.

Precision grinding and facing of copper-beryllium alloys

This paper investigates the machinability of Cu-Be alloys by ultraprecision grinding and facing. The material temper, tool geometry, and machining parameters are varied to assess their effects on surface finish. The study shows that microgrinding of Cu-Be with a diamond wheel generates a rougher surface finish as compared to that produced by microfacing with a single-point diamond tool. Similar chip formation mechanisms are observed when the depths of cut vary from few millimeters to submicron levels. A mathematical model is derived to compare the theoretical and experimental surface finish. Good agreement between predicted and measured data is obtained, providing grain boundaries are visible on a machined surface when being observed under a microscope. Feedrate and tool radius are the most influential parameters on surface finish. Flatness of 20 nm on the 9.5 mm diameter rod and roughness of 2 nm R a and 8 nm R t are achieved. Although the material’s micromachinability is the same for both the aged and unaged alloys, size and distribution of beryllides must be controlled for better tool life and surface finish.