Beryllium Copper Research Articles

Effect of Ti/Si and Ti/TiN/Si interlayers on the structure, properties, and tribological behavior of an a-C film deposited onto a C17200 copper-beryllium alloy

Reduced hardness and wear resistance may limit SAE C17200 copper‐beryllium alloy use in manufacturing applications, such as plunger tips of die casting machines and as cores and inserts for steel dies in injection molding processes. In order to improve the surface properties of Cu—Be alloys, amorphous carbon (a-C) films have been selected since these coatings may show high hardness, low wear rate and low coefficient of friction. However, the adhesion of carbonaceous films on Cu—Be alloys remains a challenge. Two interlayer compositions (Ti/Si and Ti/TiN/Si) were deposited onto Cu—Be disks and silicon wafers to assess amorphous carbon adhesion on substrates made of Cu—Be alloy. The microstructure and topography of the coatings were examined by Field Emission Scanning Electron Microscopy (FESEM) coupled with X-ray dispersive energy spectroscopy (EDS). The chemical composition depth profile was measured by glow discharge optical emission spectroscopy (GDOES), which confirmed distinct coating layers of Ti, Si, a-C (C1 and C2 conditions-pDCMS). A TiN extra layer presence was obtained for the C3 and C4 conditions-pDCMS reactive, confirmed by small angle XRD analysis. Raman scattering spectroscopy showed a higher quantity of sp3 carbon bonds for C3 and C4 coating conditions compared to C1 and C2. Instrumented indentation tests indicated a higher hardness and reduced elastic modulus for C3 and C4 coating systems, corroborating Raman results, in terms of a higher concentration of sp3 bonds. Scanning electron microscopy (SEM), atomic force microscopy (AFM), and coherence correlation interferometry (CCI) were used to characterize the coatings' surface features and scratch tracks after the tests. In addition, ramp load scratch tests were conducted to assess coating adhesion to the Cu—Be alloy substrate by measuring critical loads and the coefficient of friction. The highest critical loads to failure (Lc2) and (Lc3) were found for the Ti/TiN/Si interlayer sample (C4 condition), indicating that this interlayer improved the coating contribution to a gradual increase in the hardness and promotion of an enhanced adhesion strength of the a-C coating.

Analysis of surface roughness and energy consumption in turning of C17500 copper alloy under different machining environments and modellings with response surface method

The difficulties in machinability due to the developments in the technical properties of engineering materials increase the importance of machinability indicators such as surface quality, power or energy consumption and tool life in terms of sustainable machining. In this context, the machinability of a copper-beryllium alloy (C17500), which is used in a wide range of industries and also characterized as a hybrid material, was investigated in vortex tube cooling and dry cutting environments. First, turning experiments were performed with a coated carbide tool and varying cutting speed, feed rate and depth of cut. In the experiments, the total energy consumed during turning and the roughness of the machined surfaces were measured, and analysed experimentally and statistically. In the second stage, mathematical models were developed for the total energy consumption and average surface roughness for both cutting environments with the response surface method. As a result, the chip formation process in the turning of the Cu alloy under vortex tube cooling negatively affected the cutting power and positively contributed to the surface quality. Due to the fact that vortex tube cooling creates a cooling effect rather than lubrication, built-up layer/built-up edge (BUL/BUE) formation on the tool cutting edges caused the change in the tool geometry and thus the chip removal process became more difficult and increased the energy consumption. On the other hand, in the vortex tube cooling application, the surface roughness decreased by an average of 31.4% compared to dry cutting. Furthermore, the predictive mathematical models developed for the total energy consumption and the mean surface roughness can be used with high reliability.

Modeling, Simulation and Analysis of Intermediate Fixed Piezoelectric Energy Harvester

To address the problem that piezoelectric energy harvesters are difficult to apply in certain environments, this paper establishes the theoretical study of the intermediate fixed disc piezoelectric energy harvester (IFDPEH) based on the unimorph under concentrated force. The reliability of the model was indirectly verified by numerical simulation and Computer-Aided Engineering (CAE) simulation. The effects of load, radius ratio (piezoelectric layer/intermediate support), thickness ratio (piezoelectric layer/total thickness), and elastic modulus ratio (substrate/piezoelectric layer) on electrical energy were studied. The results indicate that the radius/thickness ratios of the IFDPEH based on aluminum and beryllium bronze are 0.05/0.31 and 0.05/0.48, respectively. In addition, through parameter comparison, it is found that the most important parameters affecting IFDPEH power are radius ratio and large load. The results are demonstrated to be meaningful for broadening the application of piezoelectric energy harvesters by the derived closed-form equations for the electrical energy along the diameters of the piezoelectric discs in the z-direction.

Hexagonal close-packed (hcp) alloys under dynamic impacts

Predictions on the mechanical behavior of metals and alloys with a hexagonal close-packed (HCP) lattice under dynamic influences in a wide range of temperatures are in demand for solving a wide range of applied problems. This article presents new results of numerical simulation showing the general similarity of the mechanical behavior of HCP titanium, zirconium, hafnium, and beryllium alloys under dynamic loadings in a wide range of temperatures. These alloys belong to the important isomechanical subgroup of HCP alloys. A model for numerical simulation of mechanical behavior of HCP alloys under dynamic loadings in a wide temperature range was proposed. The model takes into account the change in contributions to the flow stress from the mechanisms of twinning and dislocation slip in the considered subgroup of HCP alloys. A kinetic damage model was adopted to describe the damage evolution under complex stress conditions and under dynamic loading. Thus, it was possible to increase the accuracy of predicting the dynamic fracture under tensile loads including the spall fracture.

Assessment of dermal absorption of beryllium and copper contained in temple tips of eyeglasses

Dermal exposure to hazardous substances such as chemicals, toxics, metallic items and other contaminants may present substantial danger for health. Beryllium (Be) is a hazardous metal, especially when inhaled and/or in direct contact with the skin, associated with chronic beryllium disease (CBD) and Be sensitization (BeS). The objective of this study was to investigate the percutaneous penetration of beryllium and copper contained in metallic items as eyeglass temple tips (specifically BrushCAST® Copper Beryllium Casting Alloys containing Be 0.35 < 2.85%; Cu 95.3–98.7%), using Franz diffusion cells. This work demonstrated that the total skin absorption of Cu was higher (8.86%) compared to Be (4.89%), which was expected based on the high percentage of Cu contained in the eyeglass temple tips. However, Be accumulated significantly in the epidermis and dermis (up to 0.461 µg/cm2) and, to a lesser extent, in the stratum corneum (up to 0.130 µg/cm2) with a flux of permeation of 3.52 ± 4.5 µg/cm2/hour and lag time of 2.3 ± 1.3 h, after cutaneous exposure of temple tip into 1.0 mL artificial sweat for 24 h. Our study highlights the importance of avoiding the use of Be alloys in items following long-term skin contact.

Comparison of the Mechanical Properties and Microstructures of QB2.0 and C17200 Alloys.

As it is known, beryllium bronze, an important copper alloy, is widely used in the field of aerospace. Since the performance of domestic and imported beryllium bronze alloys have obvious differences, domestic beryllium bronze QBe2.0 and imported C17200 alloy were adopted, and the hardness and tensile properties of imported and domestic beryllium bronze alloys in the peak aging state were compared and analyzed. In addition, the microstructure morphologies of the C17200 alloy and QBe2.0 alloy were analyzed by SEM, EBSD, and TEM. This study adopted a data-driven exploration approach to elaborate the differences between C17200 and QBe2.0 alloy. After aging at 300 °C for 2 h (peak aging), the tensile strengths of the C17200 alloy and QBe2.0 alloy were 1357 MPa and 1309 MPa, the yield strengths were 1195 MPa and 1188 MPa, and the elongations were 5.5% and 4.0%, respectively. In the peak-aged state, the grain size, uniformity, small angle grain boundary, and twin density of the C17200 alloy were much better than those of the QBe2.0 alloy, which led to more significant grain refinement and twin strengthening effects. A large amount of γ’ phase, γ phase, and β phase were precipitated in both alloys, but the precipitation density of the γ’ strengthening phase in the C17200 alloy was much greater than that of the QBe2.0 alloy. The C17200 alloy exhibited better mechanical properties under the combined effects of the various strengthening mechanisms, which provided a guideline for the subsequent improvement of domestic alloys and laid a solid foundation for the development of new copper alloys.

Approach to enhance the heat transfer of valve seats through thermal analysis

The valve seat insert is a component of the engine cylinder head, whose primary function is to seal the combustion chamber and absorb the valve's heat, releasing it to the engine cylinder head. The valves experience high temperatures owing to high thermal loading and low heat absorption in the valve seat, which can potentially damage the engine. Therefore, the thermal characteristics of the valve seat must be optimised to increase the heat transmission between the valve and its seat. Here, three copper alloy valve seats, brass, beryllium copper, and bronze copper, were tested against the existing sintered iron valve seat, and their temperature maps were determined using actual engine operation conditions. The instantaneous heat transfer coefficients of the valves, seats, and engine cylinder head during the four-stroke cycle were evaluated using a one-dimensional thermal simulation analysis. The values obtained were used to assess the finite-element model using a three-dimensional thermal simulation in the Ansys software. The results show that the brass, beryllium-, and bronze-copper valve seats increased the overall heat flux by 4.46%, 4.16%, and 2.06%, respectively, compared to those for sintered iron. Thus, the results are essential to improve the thermal characteristics of the copper alloy valve seat imposed on the cylinder head. For validation, an experimental engine thermal survey and uncertainty magnification factors were used to validate the model. The results indicate that the maximum difference between the simulation and experimental values is 8.42%. Therefore, this approach offers a direct and comprehensible application for evaluating the temperature distribution, heat gradient, and heat flux of the cylinder head of air-cooled spark-ignition moped motorcycle engines using copper alloy valve seat materials at intermediate engine speeds. Furthermore, this method is applicable as a platform for the automotive industry to improve the heat transfer of the structural parts of internal combustion engines.

Chemical Etching of Cu98Be Alloy in Electrolyte Solutions

The process of chemical etching of Cu98Be alloy in solutions of various compositions was investigated. The rate of etching of beryllium bronze in the investigated solutions was deter-mined, and its change in time was studied. The selectivity of dissolution of the components of Cu98Be during prolonged etching in solutions of different electrolytes was established. A possibility of achieving uniform etching of Cu98Be alloy by varying the composition of the etching solution was shown. The concentrations of metal ions in the used etching solutions were determined, and the capacity of those solutions was calculated. The compositions of solutions with a high capacity for both alloy components during prolonged etching was estab-lished. The optimal compositions of etching solutions providing high-quality etching of beryl-lium bronze according to several criteria such as: a high process rate, uniform dissolution of alloy components, high capacity for both alloy components were proposed. The morphology of the Cu98Be electrode surface after etching in solutions, providing uniform dissolution for both alloy components, was studied. The absence of surface passivation after chemical etch-ing in these solutions was shown. The chemical nature of the compounds formed in the form of small inclusions on the etched surface of the electrode was established. The obtained results are of great importance in practical use because they allow selecting the appropriate composition of the etching solution, which, in turn, helps to optimize the technological etching process.

Shock wave study of precipitation hardening of beryllium copper

Based on three series of planar impact tests performed on beryllium copper samples, having thickness 0.25–6 mm, individual contributions of beryllium clusters (in the as quenched supersaturated solid solution), Guinier-Preston zones (GP, formed following ageing at 300°C for 26 min) and metastable γ" precipitates (crystallizing after 400 min ageing at 300°C) to the strength of alloy were quantified along with corresponding activation volumes. These data being coupled with Transmission Electron Microscopy evaluation of geometry and statistics of GP and γ" precipitates, made determination of the resistance τp to dislocation motion (Peierls stress) of the lattices of these particles possible. The great difference between values measured in these two cases, namely 3.7 GPa for GP and 1.4 GPa for the γ" precipitates may be considered as an additional confirmation of the fact that in these two cases the strengthening occurs due to different phases.

Structure and properties of CrN/TiN multilayer coatings deposited by vacuum arc plasma evaporation on copper and beryllium-copper alloy

Structure and properties of CrN/TiN multilayer coatings deposited by vacuum arc plasma evaporation on copper and beryllium-copper alloy

Investigating the effect of cryogenic treatment of workpieces and tools on electrical discharge machining performance

&lt;abstract&gt; &lt;p&gt;In this competitive world, manufacturers must embrace new technology in order to differentiate their products and capture market leadership. This can be achieved using advanced materials; however, these materials are difficult to machine by using traditional machining processes. A very viable and practical unconventional machining process is electrical discharge machining (EDM). EDM processes need proper selection of input parameters to get optimum productivity aspects, namely, the material removal rate and tool wear rate. Thus, the present study aims at investigating the effect of cryogenically treated work pieces and tools, gap currents, gap voltages, pulse on time and pulse off time on the material removal rate and tool wear rate during EDM of Nitinol (NiTi) alloy, Monel (NiCu) alloy and beryllium copper (BeCu) alloy. The experimental results showed that cryogenic treatment significantly improved the electrical conductivity of the workpieces and tool electrodes, which resulted in an enhanced material removal rate and reduced tool wear rate.&lt;/p&gt; &lt;/abstract&gt;

Design Aspects and Thermal Characteristics of Single-Sided Linear Induction Motor for Electromagnetic Launch Application

This paper presents the design aspects and thermal characteristics of single-sided linear induction motor (SLIM) for Electromagnetic launchers. It is designed to accelerate a 50 kg mass through a distance of 3 meters within a minuscule time to an exit velocity of 50 m/s. A study of the motor&#x2019;s parametric variation based on the launching requirement has been performed. Its performance characteristics are obtained using 3D FEM and verified analytically using Parseval&#x2019;s method. The FEM, analytical and experimental verification of the thrust characteristics of different secondary conductive sheet materials namely, aluminum, beryllium copper and German silver shows that, the latter exhibits superior characteristics than the former two, because its thrust-velocity curve is close to inverse linear relationship (stable region of operation of LIM), which significantly reduces the accelerating time during the launch. The designed SLIM is assessed for its thermal performance with materials having temperature-dependent electrical properties by carrying out a coupled-field FEM simulation. The conclusions demonstrate that the electromagnetic and thermal assessments are in tandem with each other as required for launching.

A Systematic Way of using Preference Selection Index Methodology for Selecting Suspension Coil Spring Material

Material selection serves as a foundation for all engineering applications. Inappropriate material selection would create a huge impact which in turn would affect the quality of the product in whole. In this work, the best material for suspension coil spring is selected by using a novel method. Fatigue failure of a shock absorber coil spring occurs mainly due to the improper selection of material. To improve the performance and efficiency of the shock absorber coil spring, suitable material is to be selected based on its application with considerations of the desired properties. Preference selection Index (PSI), a systematic multi-criteria decision-making approach is presented in this study for selecting the appropriate material which is considered as best. This technique is used to select the best alternatives without defining the proportionate significance of attributes. ASTM A231 steel, AISI 9255 steel, 302 Stainless Steel, ASTM A228 Steel and Beryllium Copper UNS C17200 are the various materials suitable for suspension coil spring. Through PSI method, ASTM A228 Steel is selected as a best material among the alternative materials. The PSI results are validated using the numerical analysis, basic analytical analysis and verified using the average validation method with respect to the desired attributes.

Моделирование ударно-волновых эффектов в металлах на основе релаксационной модели с дислокационной кинетикой пластических сдвигов

In the range of weak shock waves (before absorption of elastic precursors by the shock wave) the effects of shock wave deformation of aluminum and beryllium alloys are numerically studied by the relaxation model with dislocation kinetics of plastic shear. Both the structure of non-stationary and stationary shock wave profiles are modeled. The plastic flow behind the front of elastic precursors is studied.

Characterization of the Electrochemical Corrosion of a Beryllium-Bronze Alloy

Selective and efficient electrochemical analytical methods for the characterization of the corrosion behavior of beryllium bronze alloys are significant and necessary. These electrochemical methods are based on open-circuit chronopotentiometry curves, potentiodynamic polarization, and electrochemical impedance spectroscopy. From the electrochemical analysis, the results show that the corrosion reaction of the untreated samples became more severe as the NaCl concentration was increased. However, the corrosion reaction was not obvious when the alloy was treated by commercial latex paint and laboratory-produced latex paint. Furthermore, the corrosion potential has the same variation tendencies and the value of the corrosion potential was more positive when the alloy surface was treated by the laboratory-produced latex paint. The maximum and minimum of the corrosion potential were found for conditions using the untreated samples and samples treated with the laboratory-produced latex paint. The corrosion current, the charge transfer resistance, and the radius of capacitive resistance all decreased with increasing NaCl concentration. The above results suggest that the corrosion rate increased as the NaCl concentration was increased. Better anti-corrosion technology was found through various experimental analyses. The innovative electrochemical methods applied in the electrochemical corrosion behavior of beryllium bronze alloy are accurate, efficient, and reliable.

Numerical analysis of heating by a current pulse of a niobium nitride membrane in its longitudinal section

A numerical calculation of the evolution of the temperature distribution in the longitudinal section of a niobium nitride membrane when it is heated by an electric current pulse is performed. Mathematical modeling was carried out on the basis of a two-dimensional initial-boundary value problem for an inhomogeneous heat equation. In the initial boundary value problem, it was taken into account that current and potential contacts to the membrane serve simultaneously as contacts for heat removal. The case was considered for the third from the left and the first from the right initial-boundary value problem. Analysis of the numerical solution showed that effective heat removal from the membrane can be provided by current-carrying and potential clamping contacts made, for example, of beryllium bronze. This makes it possible to study the current-voltage characteristics of superconducting membranes near the critical temperature of the transition to the superconducting state by currents close to the critical density without significant heating.

The natural frequency of drum-deployed thin-walled open tubular booms

Thin-walled tape springs are extended from cylindrical deployment drums to support instruments and sensors in a cantilevered manner on spacecraft. Attaching tape springs onto the deployment drums results in a partially flattened and partially restrained cross section, which is far from the ideal case of a fixed-free beam. The consequence is a more compliant root condition that has the potential to couple and amplify on-board microvibrations with the natural frequency of the extended instrumentation. In this paper it is shown that an Euler–Bernoulli beam model can be used to calculate the natural frequency of drum-deployed tape springs using elastic boundary conditions to represent the root condition. A Finite Element (FE) model and experimental data are used to validate the beam model’s correctly predicted relationships between the natural frequency and tape spring length, f1,Res.∝L−1.5, and its rotational stiffness, f1,Res.∝krot0.5. For the investigated beryllium copper tape springs the FE model and beam model are in excellent agreement with experiment, with the error <10%. For carbon fibre epoxy tape springs there is also strong agreement between the FE model and experiment, and approximately 10%–20% error with the beam model. On a scale from a hinged beam to a fixed-free beam, the non-dimensionalised beam equation reveals that the drum-deployed tape springs are close to the hinged beam end of the scale. Two stiffening methods are proposed to increase the stiffness of the tape springs, and hence move the tape springs towards being a fixed-free beam.

Tribological Performance of Copper-Titanium Alloy under Dry Sliding Contact

Abstract Frictional heating leads to sparking and excessive wear of components in engineering applications. Until now, copper-beryllium alloys have been used extensively in frictional contacts where nonsparking ability is desired. However, copper-beryllium creates an inhalation hazard when there is exposure to the dust or fumes from beryllium metal, metal oxides. Besides nonsparking ability, an environmentally friendly alternate material having equally good electrical and tribo-mechanical properties needs to be developed. In achieving the objective of this article, tribological properties of copper titanium alloy as an alternative under dry sliding contact were investigated and compared. Experiments were conducted on copper-titanium alloy having 2 % and 4.2 % titanium sliding against an EN-31 disk using a pin-on-disk apparatus. Taguchi-based design of experiments was used to find out significance of parameters and their effect on friction coefficient and wear rate. The microstructure was studied for distribution of titanium powder in alloy and its effect on grain distribution vis-à-vis tribo-properties using scanning electron microscopy analysis. It was found that the coefficient of friction decreases as titanium concentration and velocity increase. Titanium concentration has a significant effect on reducing wear. Results are indicative for potential use of copper-titanium alloy instead of copper-beryllium alloy. Because copper-titanium is a more recent material, its tribological properties are yet to be researched. Apparently, hardly any literature is available exclusively in this type of application.

Phase Composition, Structure, and Properties of Beryllium Bronze after Thermal and Thermoacoustic Treatment

Phase Composition, Structure, and Properties of Beryllium Bronze after Thermal and Thermoacoustic Treatment

Improvement of the technological process of processing parts of coaxial radio components using thermal impulse deburring

Purpose of the study is to improve the technological process of manufacturing small-sized parts of coaxial radio components from beryllium bronze and alloy 29 NK to reduce costs and obtain stable quality at the stage of machining. Analysis of the characteristics of parts of coaxial radio components and methods of deburring has shown that a promising method is thermal impulse deburring. For complete removal of burrs by the thermal impulse method, the selection of the tool and processing modes at the stage of blade processing was carried out in order to obtain a normalized size of burrs. The thermal impulse deburring experiment showed complete deburring while maintaining the geometry of the parts. The design of the tooling and devices for placing parts in it are proposed. The calculation of the base pressure and the required volume of the gas mixture for processing the loaded batch of parts has been developed. The calculation of the size of the batch of loading and the time of thermal impulse treatment for the production program has been developed. A technique for choosing equipment for a thermal impulse treatment section is proposed. The results of the research performed can be used to apply the operation of thermal impulse deburring in the technological process of manufacturing small-sized parts from beryllium bronze and alloy 29 NK.