Beryllium Copper Research Articles

The influence of damping resistance on first swing stability of turbine generator considering stator transient

Generally, the ignored stator transient of turbine generator result in the unidirectional electromagnetic torque caused by damping resistance is neglected. While, the unidirectional electromagnetic torque has a braking effect which can reduce the rotor acceleration following the disturbance and improve the stability of power system. With a 300 MW turbine generator as an example, the large disturbance characteristic and First Swing Stability (FSS) limit are calculated by Time-Step Finite Element Model (T-S FEM) and three practical models of turbine generator in this paper. The unidirectional electromagnetic torque caused by stator transient is investigated and its important role in FSS is analyzed. Since there are several material options for damping windings, the influence of damping resistance on the large disturbance characteristic and FSS limit are calculated and compared under different damping resistance. The result shows that the FSS limits calculated by the practical model with stator transient are increased than that without stator transient; the FSS limits of turbine generator with damping windings made from stainless steel are larger than that made from aluminum and beryllium bronze by the four kinds of generator models. The result provides theoretic basis of generator modeling for precise simulation of power systems.

Mössbauer monitoring of alloys homogeneity

The possibility of monitoring structure homogeneity has been studied by the method of Mossbauer spectroscopy with a resonance detector on the example of beryllium alloys, containing from 0.09 to 0.8 wt.% iron and other metallic impurities with a total amount of 0.04 to 0.14 wt.%. The quality of the obtained spectra description has been improved using methods which have a different degree of complexity and effectiveness.

Positron annihilation spectroscopy studies of bronze exposed to sandblasting at different pressure

An application of Doppler broadening of annihilation line spectroscopy to samples of beryllium bronze DIN-CuBe2 exposed to sandblasting is presented in performed studies. It is familiar that sandblasting introduces open-volume defects. Samples were sandblasted under different pressure for 1 minute using 110 μm particles of Al2O3. For a non-defected sample the constant value of S-parameter was detected. In the cases of sandblasted samples, S-parameter decreased when the depth enhanced. In our studies the thicknesses of defected zones were determined (it was c.a. 30 μm for a sample blasted under pressure of 1 bar and 110 μm – for 5 bar), and it was also observed that if sandblasting pressure is higher the defected zone is larger.

A low-background piston–cylinder-type hybrid high pressure cell for muon-spin rotation/relaxation experiments

ABSTRACTA low background double-wall piston–cylinder-type pressure cell is developed at the Paul Scherrer Institute. The cell is made from BERYLCO-25 (beryllium copper) and MP35N nonmagnetic alloys with the design and dimensions which are specifically adapted to muon-spin rotation/relaxation (μSR) 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 materials 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 a softer inner CuBe cylinder enables pressures of up to 2.6 GPa to be reached at ambient temperature, 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 μSR signal.

Micro-EDM drilling of high aspect ratio micro-holes and in situ surface improvement in C17200 beryllium copper alloy

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.

An improved electronic determination of the Boltzmann constant by Johnson noise thermometry

Recent measurements using acoustic gas thermometry have determined the value of the Boltzmann constant, k, with a relative uncertainty less than 1 × 10−6. These results have been supported by a measurement with a relative uncertainty of 1.9 × 10−6 made with dielectric-constant gas thermometry. Together, the measurements meet the requirements of the International Committee for Weights and Measures and enable them to proceed with the redefinition of the kelvin in 2018. In further support, we provide a new determination of k using a purely electronic approach, Johnson noise thermometry, in which the thermal noise power generated by a sensing resistor immersed in a triple-point-of-water cell is compared to the noise power of a quantum-accurate pseudo-random noise waveform of nominally equal noise power. The experimental setup differs from that of the 2015 determination in several respects: a 100 Ω resistor is used as the thermal noise source, identical thin coaxial cables made of solid beryllium–copper conductors and foam dielectrics are used to connect the thermal and quantum-accurate noise sources to the correlator so as to minimize the temperature and frequency sensitivity of the impedances in the connecting leads, and no trimming capacitors or inductors are inserted into the connecting leads. The combination of reduced uncertainty due to spectral mismatches in the connecting leads and reduced statistical uncertainty due to a longer integration period of 100 d results in an improved determination of k = 1.380 649 7(37) × 10−23 J K−1 with a relative standard uncertainty of 2.7 × 10−6 and a relative offset of 0.89 × 10−6 from the CODATA 2014 recommended value. The most significant terms in the uncertainty budget, the statistical uncertainty and the spectral-mismatch uncertainty, are uncorrelated with the corresponding uncertainties in the 2015 measurements.

Colossal multi-resonant magnetoelectric response in Fe73.5Cu1Nb3Si13.5B9/Terfenol-D/Be-bronze/Pb(Zr,Ti)O3 structure at zero bias magnetic field

This paper reports multi-resonant magnetoelectric (ME) response at zero bias magnetic field in structure Fe73.5Cu1Nb3Si13.5B9/Terfenol-D/Be-bronze/PZT (FTBP) consisting of a composite magnetic layer Fe73.5Cu1Nb3Si13.5B9/Terfenol-D, a elastic beryllium bronze (Be-bronze) plate, and a piezoelectric Pb(Zr,Ti)O3 (PZT) plate. By using the composite magnetic layer Fe73.5Cu1Nb3Si13.5B9/Terfenol-D and the elastic Be-bronze plate, multi-resonant ME responses at zero-biased field are obtained in FTBP structure. The influences of the Be-bronze plate length and the Fe73.5Cu1Nb3Si13.5B9 foil layers on multi-resonant ME characteristics are investigated in detail. When the lengths of Be-bronze plates are 30, 50 and 70 mm, the FTBP structures have four, five and nine high resonant peaks, respectively. In range of 0.1–70 kHz, nine large peaks of zero-biased ME response with magnitudes of 0.45–7.38 V/(cm Oe) can be observed for FTBP structure with 70 mm length of Be-bronze plate and two layers of Fe73.5Cu1Nb3Si13.5B9 foil. Furthermore, the zero-biased sensitivity can reach 10.1, 226.4, 590.5 mV/Oe when detecting the 1, 7.88 and 35.26 kHz alternating current magnetic fields, respectively. These results demonstrate that the proposed ME structure may be useful for multifunctional devices such as multi-frequency energy harvesters or low-frequency ac magnetic field sensors at zero bias magnetic field.

Application of laser spot cutting on spring contact probe for semiconductor package inspection

A packaged semiconductor has to be electrically tested to make sure they are free of any manufacturing defects. The test interface, typically employed between a Printed Circuit Board and the semiconductor devices, consists of densely populated Spring Contact Probe (SCP). A standard SCP typically consists of a plunger, a barrel, and an internal spring. Among these components, plungers are manufactured by a stamping process. After stamping, plunger connecting arms need to be cut into pieces. Currently, mechanical cutting has been used. However, it may damage to the body of plungers due to the mechanical force engaged at the cutting point. Therefore, laser spot cutting is considered to solve this problem. The plunger arm is in the shape of a rectangular beam, 50μm (H)×90μm (W). The plunger material used for this research is gold coated beryllium copper. Laser parameters, such as power and elapsed time, have been selected to study laser spot cutting. Laser material interaction characteristics such as a crater size, material removal zone, ablation depth, ablation threshold, and full penetration are observed. Furthermore, a carefully chosen laser parameter (Etotal=1000mJ) to test feasibility of laser spot cutting are applied. The result show that laser spot cutting can be applied to cut SCP.

High performance bimorph piezoelectric MEMS harvester via bulk PZT thick films on thin beryllium-bronze substrate

This letter presents a high performance bimorph piezoelectric MEMS harvester with bulk PZT thick films on both sides of a flexible thin beryllium-bronze substrate via bonding and thinning technologies. The upper and lower PZT layers are thinned down to about 53 μm and 76 μm, respectively, and a commercial beryllium bronze with the thickness of about 50 μm is used as the substrate. The effective volume of this device is 30.6 mm3. The harvester with a tungsten proof mass generated the close-circuit peak-to-peak voltage of 53.1 V, the output power of 0.979 mW, and the power density of 31.99 mW/cm3 with the matching load resistance of 360 kΩ at the applied acceleration amplitude of 3.5 g and the applied frequency of 77.2 Hz. Meanwhile, in order to evaluate the stability, the device was measured continuously under applied acceleration amplitudes of 1.0 g and 3.5 g for one hour and demonstrated a good stability. Then, the harvester was utilized to light up LEDs and about twenty-one serial LEDs were lighted up at resonance under an applied acceleration amplitude of 3.0 g.

Material performance of age-hardened beryllium–copper alloy, CDA-C17200, in a high-pressure, gaseous hydrogen environment

In order to develop safer and more energy-efficient, hydrogen pre-cooling systems for use in hydrogen refueling stations, it is necessary to identify a high-strength metallic material with greater thermal conductivity and lower susceptibility to hydrogen embrittlement, as compared with ordinary, stable austenitic stainless steels. To accomplish this task, the hydrogen compatibility of a precipitation-hardened, high-strength, copper-based alloy was investigated by slow-strain-rate tensile (SSRT), fatigue-life, fatigue-crack-growth (FCG) and fracture toughness tests in 115-MPa hydrogen gas at room temperature. The hydrogen solubility and diffusivity of the alloy were also determined. The hydrogen solubility of the alloy was two or three orders of magnitude lower than that of austenitic stainless steels. The alloy also demonstrated absolutely no hydrogen-induced degradation of its strength properties, a factor which could contribute to the reduction of costs related to the construction and maintenance of hydrogen refueling stations, owing to the downsizing and improved cooling performance of the pre-cooling systems.

Research on micro-EDM with an auxiliary electrode to suppress stray-current corrosion on C17200 beryllium copper alloy in deionized water

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.

Study of Outgassing and Removal of Tritium from Metallic Construction Materials of ITER Vacuum Vessel Components

The subject of this study is the evaluation of tritium outgassing and removal from metals such as tungsten, beryllium, stainless steel, and copper alloy. In addition, a composite sample assembled from tungsten, copper alloy, and stainless steel was also studied. Samples of individual materials and composite samples were of thicknesses and compositions representing the internal components of the ITER vacuum vessel. The samples of materials were loaded with tritium by exposure to a gaseous tritium-deuterium mixture (about 1:1) at a temperature of 473 K and a pressure of about 0.05 MPa. The rate of outgassing was measured at temperatures of about 295, 308, and 323 K under static or dynamic atmospheres either of ambient air or dry air or argon. The study allows recommendation of conditions for storage of in-vessel components and reduction of the rate of tritium outgassing. The metals’ samples were also subject to study of tritium removal by thermal desorption under purge with argon containing 5 vol % of hydrogen. The study has demonstrated that this detritiation procedure allows for removal of large portions of the tritium inventory and substantial reduction in tritium outgassing rates.

Lead-Free Solders for Copper Alloy Wire Mesh

The wetting of compact materials made of pure copper and copper bronzes (tin, beryllium, aluminum) by low-temperature tin-based solders is studied with the sessile drop method with drop melt capillary purification in the experiment. The Sn–Ag–Cu solders wet the bronzes more actively than Sn–Pb (POS-61) and Sn–Bi alloys. The wetting of vacuum-annealed copper and bronze substrates by POS-61, O-2, Sn–Bi, CASTIN, and SAC alloys show that copper and beryllium bronze are wetted by solder alloys better. The Sn–Ag–Cu solders and Sn–Bi alloys are used for metallization and soldering of copper mesh structures. Soldered copper wire 0.1 mm in diameter is obtained to produce mesh representing a knitted soldered structure. The resistivity of O-2, SAC, Sn–Bi, and POS-61 alloys and the surface resistivity of the knitted soldered copper mesh are determined. The metallization of copper wire and soldering of mesh knots substantially influence the mesh surface resistivity.

Role of the structural state of a copper–beryllium alloy in the formation of its tribotechnical properties

The influence of the structural state of a copper–beryllium alloy on its resistance to friction fracture under adhesion interaction and abrasive wear has been investigated. It has been shown that the elastic interphase deformations that cause the tension of the crystal lattice of the particles of precipitated phase brings about a decrease in the wear resistance of the alloy at a retained high hardness. The relaxation of interphase deformations during the aging process leads to a significant increase in the wear resistance of the alloy, despite the reduction its hardness.

Thermo-electric modelling, simulation and experimental validation of powder mixed electric discharge machining (PMEDM) of BeCu alloys

Beryllium copper alloy has high strength, nonmagnetic, good wear resistance, corrosion resistance, high fatigue strength and non-sparking qualities. These properties impose machining issues when machined by conventional machining processes. Electric discharge machining is a practically viable solution to machine such materials. Recently researchers have been attracted by powder mixed electric discharge machining with the advancement in technology. Present study focuses on developing Finite Element model of Powder Mixed Electric Discharge Machining of Beryllium copper alloy with experimental validation. An axis symmetric three-dimensional model has been developed and simulated using ANSYS 15.0 software for obtaining the temperature distribution on the surface of workpiece during a single discharge machining process. And the temperature profile was utilized to estimate the material removal rate. Experiments were performed to validate the numerical results. The average percentage error of 7.8% was obtained between numerical and experimental results. Thus, a good agreement between the experimental and numerical results shows that the software model can efficiently simulate and predict the real time results.

Formation of microstructure and properties of Cu-3Ti alloy in thermal and thermomechanical processes

Abstract This paper presents the possibilities of forming the microstructure as well as mechanical properties and electrical conductivity of Cu-3Ti alloy (wt.%) in thermal and thermomechanical processes that are a combination of homogenising treatment, hot and cold working, solution treatment and ageing. Phase composition of the alloy following various stages of processing it into the specified semi-finished product was being determined too. It was demonstrated that the application of cold plastic deformation between solution treatment and ageing could significantly enhance the effect of hardening of the Cu-3Ti alloy without deteriorating its electrical conductivity. It was found that for the investigated alloy the selection of appropriate conditions for homogenising treatment, hot and cold deformation as well as solution treatment and ageing enables to obtain the properties comparable to those of beryllium bronzes.

X-ray radiography of cavitation in a beryllium alloy nozzle

Making quantitative measurements of the vapor distribution in a cavitating nozzle is difficult, owing to the strong scattering of visible light at gas–liquid boundaries and wall boundaries, and the...

Influence of Cold work on aging response of C17200-Beryllium Copper Alloy C17200

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.

Ion drift meter aboard China seismo-electromagnetic satellite

A lot of electromagnetic anomalies observed by satellites before earthquakes indicate that there is interrelation between earthquake and ionosphere.China seismo-electromagnetic satellite (CSES) is the first Chinese space-based platform of three-dimensional earthquake monitoring system.The scientific payload of plasma analyzing package (PAP) aboard CSES is designed to study the possible influence of the seismic activity on the ionospheric plasma and thereby to monitor the earthquakes from space.The PAP is made up of three sensors,retarding potential analyzer (RPA),ion drift meter (IDM),and ion capture meter (ICM).The main objective of IDM is to detect the ion bulk velocity from-3 to 3 km/s with a precision better than 20 m/s,perpendicular to the sensor-look direction. The IDM sensor consists of six-layer grids and a collector.The grid is made of beryllium copper,plated with gold.Polyimide is used to achieve electrical insulation between grids.The grid transmission rate of signal layer is designed to be 82.64%,and total transmission rate of six layers is 31.85%.To ensure the performance of IDM,the side length of the square aperture and the depth of the sensor are designed to be 40 and 20 mm,respectively.The radius of segmented planar collector is 50 mm.The arrival angle of the ions is determined by measuring the ratio between the currents from the different electrically isolated collector segments.Accordingly,velocity perpendicular to the sensor-look direction is calculated,based on arrival angle and ion velocity parallel to the sensor-look direction which is measured by the RPA. In addition,a wide-range and high-precision current measurement circuit is designed to measure the current of IDM.The preamplifier circuit has three measurement ranges,providing different amplification factors.The right measurement range is chosen automatically by the field programmable gate array (FPGA).The test results show that the circuit provides a total measuring dynamic range from 20 pA to 6A with an accuracy better than 0.4%. Finally,the method of testing in the plasma environment and the measurement results are discussed.The plasma environment test of the IDM flight model is carried out in the Institute for Space Astrophysics and Planetology,National Institute of Astrophysics (INAF-IAPS).Since the plasma source is fixed to a large volume vacuum tank,the arrival angle of the plasma with respect to the sensor-look direction is changed by horizontally or vertically mounted IDM on the rotating platform in the vacuum tank.As the platform rotates,the performance of IDM is proved by testing different ion arrival angles in vacuum tank.The ion velocities along the Y and Z axes of the spacecraft are validated by testing the horizontal arrival angle and the vertical arrival angle respectively.The IDM test data are consistent with those obtained under the setting angle of the rotating platform.The experimental results show that the detector has good performance and will fulfill the mission goal of monitoring the bulk velocity of ion,perpendicular to the sensor-look direction.

Research on retarding potential analyzer aboard China seismo-electromagnetic satellite

China seismoelectromagnetic satellite (CSES) is the first space-based platform of three-dimensional earthquake monitoring system in china. Plasma analyzing package (PAP) is one of scientific payloads aboard on CSES, which is the first application to the field of Chinese satellite. The main scientific objective of PAP is to measure ion density, ion temperature, ion composition and ion drift velocities (parallel and perpendicular to the direction of the satellite flight on orbit), and ion density fluctuation in the ionosphere. The PAP payload is composed of four parts, including retarding potential analyzer (RPA), ion drift meter, ion capture meter, and metal plate. The RPA is used to test ion density, ion temperature, ion composition and ion drift velocity (parallel to the direction of the satellite flight on orbit). The detailed design process of the sensor of RPA is described in this paper. The grid of RPA sensor is made of Beryllium copper, plated with gold to ensure uniform surface work function, and to prevent space atomic oxygen from eroding. The design value of the transmission rate of grid is 82.64%1.4%, with taking into account the Debye length on the orbit of satellite. And the total transmission rate of multilayer grid for RPA is verified by SIMON simulation experiment. To ensure the accuracy of RPA, the radii of sensor window and sensor collector are designed to be 20 mm and 50 mm respectively, and the height of sensor is 20 mm. The sweeping voltage ranges from -2 V to 20 V. And the step of sweeping voltage is adjustable between 0.056 and. 179 V. In this paper electronic design of RPA is also discussed. The electronic box is composed of preamplifier circuit, digital logical circuit, satellite interface circuit, etc. The sweeping voltage and the signal acquisition are controlled by field-programmable gate array. The design of three measurement ranges in digital logical circuit improves RPA measurement accuracy, which is better than 1.3% in the full range. In addition, the method of testing the plasma environment and the testing results are introduced. The plasma environment test of the RPA payload is carried out in INAF-IAPS. The performance of ion density measurement is validated by testing different ion densities in a vacuum tank, through changing three different distances between RPA and the plasma source. And the ion drift velocity measurement is verified by testing three different ion energies of the plasma source. Furthermore, the RPA test data are consistent with the test data from the INAF-IAPS reference RPA. The experimental results show that the detector has good performances and will contribute much to monitoring the space plasma parameters.