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A special type of flexure bearings are installed to support a compressor motor and a displacer within a cryocooler which is used in space applications. The fatigue life of spring is a critical factor for such applications, to ensure that the cryocooler does not fail. The flexure spring is used in the setup of an eccentric type of flexure bearing. The present study analyzes various significant parameters and properties in selecting the best suitable material to achieve finite-fatigue life. To avoid a failure of such critical component, batch testing is carried out. The three materials which are compared with respective SN-curve are a] beryllium copper, b] Stainless Steel (3 0 4) and c] Titanium. The study has been carried out to find the best suitable material for flexure bearing. Finite Element Analysis (FEA) is used to understand flexure springs stress and displacement.

Flexure spring is thin metallic disc used to allow relative motion by bending between the piston and the fixed support in compressor body. The flexure spring deforms by the force applied by piston and come back to its original position. As spiral arms cut from its surface, flexing takes place. The main object of this article is to optimize the spring material to enhance the service life of spring. The present article analyzes five different copper based alloys as these materials are having elasticity property. Initially the model was prepared in Catia software. The Finite Element Analysis (FEA) was carried out by applying boundary conditions. As the total displacement of piston is 10 mm so force is applied at the central hole in such a way that the spring will deform for 5 mm from mean position. Due to applied load stresses will develop in the flexure. The equivalent stress was observed for chosen materials. The equivalent stresses were compared with permissible stress for that material by considering factor of safety (FoS). The cold drawn copper and the Beryllium copper UNS C (TH02) found suitable for flexure spring having the stress within permissible limit. As stiffness is also important property for spring. The deformation was observed in FEA for these two materials by applying 1 N force. The stiffness was calculated. The material was selected which will give maximum stiffness. It was found that the Beryllium copper UNS C (TH02) shows the maximum stiffness.

The electro chemical machining system is the type of system in which it is used in the machining operations. In our project we have analyse the erosion in the electro chemical machining tool. The main disadvantage of the electrochemical machining system is that, due to repeated use of electrochemical machining tool there may be occurance of erosion in the machining tool. This effect is due to the presence of oxygen content in the electrolyte. We compared different types of metal like beryllium copper, copper tungsten, copper and brass with the electrolyte combination of sodium chloride and sodium nitrate. Normally the electrolyte used in the electro chemical machining system is that the sodium chloride and sodium nitrate [5] . So that we have used to compare the metals and electrolytes and used to find the best among them. Finally we have concluded that the beryllium copper has the best results. So the use of berylliumcopperwiththeelectrolyteofsodiumchloridewill havethereductionintheerosion.

The current investigation is, to determine the optimum process variables on CNC turning operation of Be-Cu (C17200) alloy using grey relational approach (GRA). In GRA, optimum level of turning variables can be identified by the grey relational grade as the performance index. In present work, the three turning variables were chosen namely cutting speed (V1 = 800 rpm, V2 = 1000 rpm and V3 = 1200 rpm), feed rate (F1 = 0.10 mm/rev, F2 = 0.12 mm/rev and F3 = 0.14 mm/rev) and depth of cut (D1 = 0.8 mm, D2 = 1.0 mm and D3 = 1.2 mm) and the output responses such as material removal rate (MRR) and surface roughness (SR) were considered. A grey relational grade attained from the GRA was used to identify the optimum turning process variables on multi response characteristics with an objective to maximize the MRR and minimize the SR. Based on the grey relational grade, optimum level of turning variables was identified as V3F3D2 that is cutting speed at level 3 (1200 rpm), feed rate at level 3 (0.14 mm/rev) and depth of cut at level 2 (1.0 mm). The significant effect of each variable on response was determined by analysis of variance (ANOVA). From ANOVA result shows that cutting speed was the most significant factor on multi response characteristics followed by depth of cut. Finally, the verification test was performed to validate the experimental results.

Fabrication of superhydrophobic surface (SHS) on metal can effectively enhance its utility value. Herein, electrochemical etching for the electrical discharge machining (EDM) surface of beryllium copper (Be-Cu) alloy is carried out in the hydrochloric acid electrolyte, to obtain a hierarchical micro-nanostructure. After modification by stearic acid, the contact angle is up to 167.1 ± 2.6° and the sliding angle to 2.4 ± 0.7°. The microstructure constructed by EDM improves the quality of the SHS availably. The corrosion and abrasion resistance tests show that the performance is significantly higher than that without EDM. EDM can be used as a pretreatment process for the fabrication of SHS. It can also be applied to the EDM functional unit of parts to achieve specific functions. In addition, EDM for hole, the inner wall of the superhydrophobic hole was obtained, confirmed the excellent self-cleaning performance. This method has a good application prospect in the fabrication of SHS of metallic engineering materials.

Copper alloys have important industrial roles due to their excellent properties. Beryllium copper is one of the copper-based alloys with the highest strength and excellent metal working and machining properties. Beryllium copper alloy composite is fabricated by the stir casting method. Its characteristics are studied with scanning electron microscopy and energy dispersive analysis of X-rays. The material properties of the stir cast beryllium copper alloy composites are evaluated. Hardness can be increased by the addition of silicon carbide particles. Abrasive water jet machining is an effective unconventional machining process, in which high pressure water jet and abrasive particles are used to remove material. Response parameters such as material removal rate and circularity of holes are considered. Response parameters of abrasive water jet machining are compared to electrical discharge machining. The most influential factor for the responses is determined by analysis of variance. Optimization of machining parameters is performed with the Taguchi method.

This paper presents the effect of micro-drilling parameters such as pulse on time, pulse off time and servo voltage to analyze tool wear in electrical discharge machine (EDM). In this work, hard material beryllium copper is selected as a workpiece to study the optimal parameter in micro-drilling processes in EDM to find the optimal tool wear for the copper electrode. Micro-drilling experiments were performed by changing the parameter levels. This paper deals with the response surface methodology approach for optimizing the tool wear. The experiments were designed based on response surface design where the Box–Behnken design method was used, and the results were analyzed using a microscope. The outcome of the parameters on tool wear was determined by performing an analysis of variance (ANOVA) and regression analysis is performed with significant interactions. The results indicate that the predicted values are closer to the experimental values with a maximum deviation of 12.03%. It shows clearly that the experimental models are in good agreement with the mathematical model and optimal values.

Shock absorber is a mechanical device designed to smooth out or damp shock impulse, and dissipate kinetic energy. In this work, suspension system is designed and a 3D model is created using CATIA V5R21. Structural analysis is done on the shock absorber by varying different spring materials. Spring materials are spring steel, phosphorus bronze, beryllium copper, and titanium alloy. To validate the strength of the model, the structural analysis on the helical spring is done. The analysis is done by considering loads, bike weight, and single, double riding. Finally, comparison is done for different materials to verify which material suits for spring in shock absorber.

A spring beam in a miniature electrical switch enables the two electrical contacts to either close or separate and supplies both current and necessary contact pressure between the contacts. Arc erosion and material transfer between the contacts occur, and those aspects depend on various parameters including the kinematics of the contacts. Therefore, the mechanical properties of the spring beam will affect the arc erosion and material transfer, but this topic has not been well studied. In this study, the material transfer phenomena between two AgCu contacts attached to a spring beam made of three different copper-based strip alloys were investigated after 30,000 switching operations under 12 V and 9 A in a direct-current resistive load circuit. For spring beams made of beryllium copper (BeCu) and titanium copper (TiCu) alloy, the material transfer occurred from the cathode to the anode. However, an opposite material transfer occurred for a spring beam made of Corson-type (CuNiSi) alloy. The make- and break-arc voltage waveforms were analyzed, and the results showed that the changes in arcing behaviors depend on the spring beam material. The properties of the spring beam materials responsible for the changed arcing behaviors are discussed and their relationship with the observed contact arc erosion and material transfer is analyzed.

Conference: 3rd International Conference on Materials and environmental Science (ICMES) Location: ‏ Agadir, MOROCCO Date: ‏ DEC 18-20, 2019 In this study, WC/C coating was applied on beryllium (Be)-copper (Cu) mould alloy by arc physical vapor deposition (PVD) as a corrosion and wear protection barrier against alumina ball in a 3.5 wt% NaCl solu- tion. Tribocorrosion tests were carried out in a triboelectrochemical cell using a ball-on-plate tribometer integrated with a potentiostat for electrochemical control. The results showed a clear improvement of wear resistance on the WC/C coating without reducing the corrosion behavior in a 3.5 wt% NaCl solution. (C) 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of The Third International Conference on Materials and Environmental Science. Bilecik Şeyh Edebali Üniversitesi Bilimsel Araştırma Projesi - BAP - 2018-01.BŞEÜ.03-03. Bilecik Seyh Edebali University Scientific Research Project - BAP - 2018-01.BŞEÜ.03-03. WOS:000544883200019

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.

Superhydrophobic surfaces have a wide application prospect in the future industrial production due to its special abilities. The fabrication of superhydrophobic coating on metal surfaces can improve its performance. A one-step electrodeposition method is proposed to construct nanostructures on the surface of beryllium copper (Be-Cu) alloys, and a mixture of copper chloride and stearic acid is used as the electrolytes. The static contact angle of water on the surface can reach up to 163 ± 4°, a sliding angle of 1.7 ± 0.2°. The nanostructure and chemical composition on the surface were evaluated by scanning electron microscopy and X-ray photoelectron spectroscopy respectively. The corrosion resistance was tested through electrochemical measurement. It was found that the as-prepared superhydrophobic coating improved the corrosion resistance significantly. In addition, the coating with excellent self-cleaning performance was proved. This method solves the problems of complicated process, improves the efficiency effectively, and the electrolyte is eco-friendly.

Pure copper, tin copper and beryllium copper were exposed to a harsh marine environment, and the effects of tin and beryllium addition on copper corrosion were systematically investigated and compared. The corrosion rate for pure copper was similar with that for tin copper, but significantly higher than that for beryllium copper, indicating an improvement in corrosion resistance due to the addition of beryllium. Pitting corrosion occurred in all investigated materials and the extent of pitting damage was in the order of pure copper > tin copper > beryllium copper. Flaking corrosion was prominent on tin copper plate after long-term exposure and the primary corrosion products in all materials were Cu2O, CuCl and Cu2Cl(OH)3. The tin content in the inner corrosion layer was higher than in the outer layer for tin copper, whereas beryllium accumulated at the outer layer of beryllium copper, confirmed by auger electron spectroscopy, and related corrosion mechanisms were proposed.

In this study, the characteristics of thin semi-rigid cables composed of different conductors and with outer diameters ranging from 0.86 to 1.19 mm were investigated at low temperatures. The thermal conductance was measured between approximately 1 and 8 K, and the frequency dependence of the attenuation in the cables was obtained at 3 K. The electrical conductors used in the cables were alloys: beryllium copper, brass, stainless steel (SUS304), phosphor bronze, cupronickel (CuNi), and niobium–titanium (NbTi). The thermal conductance of a commercial miniature coaxial cable with braided wires forming the outer electrical conductor was also examined for reference. The measured thermal conductance was compared to published data and that generated from material libraries and databases. Among the measured cables using normal metals, the semi-rigid cable composed of SUS304 conductors and a polytetrafluoroethylene insulator showed the lowest thermal conductance. The transmission performance of the semi-rigid cables using SUS304 or CuNi was improved by plating the central conductors with a silver coating of approximately \(3~{\upmu }\hbox {m}\) thickness, and their thermal conductance with the plating increased by approximately one order of magnitude. The superconducting NbTi semi-rigid cable exhibited the lowest thermal conductance of all the cables considered in the present study along with very small attenuation up to above 5 GHz.

Beryllium copper alloys are the ideal materials to fabricate the supporting parts owing to their excellent physical and chemical properties. Many high aspect ratio micro-holes are often required to realize the special missions. However, they were not easily fabricated by the traditional machining methods owing to the materials' mechanical strength. Here, we presented a high efficiency method for drilling high aspect ratio micro-holes on C17200 beryllium copper alloy by combining deionized water based micro-EDM and in situ PMEDM with boron carbide additives. The machining parameters were systematically investigated and optimized to realize the ever high aspect ratio of 23.26 at the holes' diameter of 215 μm. The surface quality of the micro-hole was improved further by in-situ PMEDM, which was demonstrated by the decreasing of surface roughness (Ra) from 2.65 μm to 0.92 μm. Our method will open an avenue to fabricate high aspect ratio micro-holes on C17200 with high efficiency.

Among the appearance defects of injection molded products, sink mark near the gate accounts for a large proportion, especially for the precision products that require a high appearance quality. The traditional method to relieve gate sink mark is to increase packing pressure and packing time. Even so, the problem cannot be completely solved. In current study, a three-dimensional numerical simulation method was employed to analyze the formation mechanism of gate sink mark. The analyses point out that high shear in the filling stage, melt refilling in packing stage and high mold temperature lead to the imbalance of shear heat generation and cooling between the gate and other regions, and finally result in the relatively high temperature and the sink mark defect in the gate region. Based on these results, a novel and simple method for improving gate sink mark by adding beryllium copper insert in the runner was proposed and implemented. Further simulation shows that the method is effective in eliminating the gate “hot spot” and improving the temperature uniformity of the entire product. The experiment results also prove that the heat sink mark in the gate area can be effectively avoided by using the mold with insert for both amorphous ABS and semi-crystalline PP products. The proposed method can not only solve the sink mark problem effectively, but also has the advantage of being simple and easy to achieve because the slide type side gate design is adopted.

A low background double-wall piston-cylinder-type pressure cell is developed at the Paul Scherrer Institute. The cell is made from BERLYCO-25 (beryllium copper) and MP35N nonmagnetic alloys with the design and dimensions which are specifically adapted to muon-spin rotation/relaxation (muSR) measurements. The mechanical design and performance of the pressure cell are evaluated using finite-element analysis (FEA). By including the measured stress-strain characteristics of the material into the finite-element model, the cell dimensions are optimized with the aim to reach the highest possible pressure while maintaining the sample space large (6 mm in diameter and 12 mm high). The presented unconventional design of the double-wall piston-cylinder pressure cell with a harder outer MP35N sleeve and asofter inner CuBe cylinder enables pressures of up to 2.6 GPa to be reached at ambient temperatures, corresponding to 2.2 GPa at low temperatures without any irreversible damage to the pressure cell. The nature of the muon stopping distribution, mainly in the sample and in the CuBe cylinder, results in a low-background muSR signal.

Beryllium copper alloys known as high-reliability engineered materials are widely used in many engineering fields. Micro-electrical discharge machining (micro-EDM) provides a safely and effectively machining process to machine beryllium copper alloys regardless of their toxicity and mechanical strength. During micro-EDM, the higher material removal rate and the lower electrode wear rate are observed when deionized water is used as a dielectric fluid. However, there are many stray-current corrosion pits on the end surface of holes which directly affect the performance and life span of parts. In this study, the method of auxiliary electrode was used to suppress the effects of stray-current corrosion on the end surfaces of holes on C17200 beryllium copper alloy. The end surfaces of holes were protected by sacrificing the auxiliary electrode. The feasibility of micro-EDM with an auxiliary electrode was verified by an experiment of a hole machined with half coved by the auxiliary electrode and the others without. The effects of the thickness of the auxiliary electrode on end surface quality and machining time were studied. The effects of the auxiliary electrode to suppress stray-current corrosion on C17200 beryllium copper alloy were proved under diffident pulse currents and pulse widths. Machining time and electrode wear were investigated. The results show that the electrode wear is scarcely affected by the auxiliary electrode. However, the machining time is slightly increased when the pulse current is lower than 0.55 A, and the pulse width is shorter than 20 μs. Beyond that level, the effect of the auxiliary electrode on machining time is not obvious. The end surface quality decreases when the pulse width is longer than 20 μs. In addition, the results also show that, when the thickness of the auxiliary electrode is 60 μm, a value of 0.34 A pulse current and 20 μs pulse width could be considered as ideal parameters for C17200 beryllium copper alloy machined by micro-EDM with an auxiliary electrode in deionized water. Furthermore, it is confirmed that the auxiliary electrode can be easily fixed on different radii of curvature surface and effectively protect the end surface of micro-holes from stray-current corrosion.

Progress in materials science requires deeper understanding of the correlation of properties to internal structure and how they get altered to tailor the required properties. The paper aims to explore the variation in the mechanical properties on the degree of cold work in Beryllium copper. Hardness increased with the increase in the degree of cold working and was observed that the hardness saturated beyond 40% cold work. The samples of various percentages of cold work were subjected to ageing treatment at 330°C for one hour and the trend of hardness is explained. The microstructures revealed the evolution of precipitates during aging that attributed to increase in the hardness. Dislocation density is predicted to increase during cold work and thus improving the kinetics of precipitation. Results show a very good agreement between reported experimental observations and predictions.