Beryllium Wire Research Articles

Form measurement of a 0.1 mm diameter wire with a chromatic confocal sensor, with associated uncertainty evaluation

The accurate characterisation of a copper–beryllium wire with a diameter of 0.1 mm is one of the steps to increase the precision of future accelerators’ pre-alignment. Novelties in measuring the wire properties were found in order to overcome the difficulties brought by its small size. This paper focuses on an implementation of a chromatic-confocal sensor leading to a sub-micrometric uncertainty on the form measurements. Hence, this text reveals a high-accuracy metrology technique applicable to objects with small diameters: it details the methodology, describes a validation by comparison with a reference and specifies the uncertainty budget of this technique.

Object image correction using an X-ray dynamical diffraction Fraunhofer hologram

Taking into account background correction and using Fourier analysis, a numerical method of an object image correction using an X-ray dynamical diffraction Fraunhofer hologram is presented. An example of the image correction of a cylindrical beryllium wire is considered. A background correction of second-order iteration leads to an almost precise reconstruction of the real part of the amplitude transmission coefficient and improves the imaginary part compared with that without a background correction. Using Fourier analysis of the reconstructed transmission coefficient, non-physical oscillations can be avoided. This method can be applied for the determination of the complex amplitude transmission coefficient of amplitude as well as phase objects, and can be used in X-ray microscopy.

Numerical reconstruction of an object image using an X-ray dynamical diffraction Fraunhofer hologram

A numerical method of reconstruction of an object image using an X-ray dynamical diffraction Fraunhofer hologram is presented. Analytical approximation methods and numerical methods of iteration are discussed. An example of a reconstruction of an image of a cylindrical beryllium wire is considered. The results of analytical approximation and zero-order iteration coincide with exact values of the amplitude complex transmission coefficient of the object as predicted by the resolution limit of the scheme, except near the edges of the object. Calculations of the first- and second-order iterations improve the result at the edges of the object. This method can be applied for determination of the complex amplitude transmission coefficient of amplitude as well as phase objects. It can be used in X-ray microscopy.

Determining the temperature-dependent characteristic temperature of beryllium from electrical resistance measurements

We have developed an intermediate-level laboratory experiment to determine the temperature- dependent characteristic temperature of beryllium. The apparatus used to measure the resistance of a beryllium wire sample between liquid nitrogen and room temperatures was simple. The characteristic temperatures obtained from these data using the Block–Grüneisen model are in reasonable agreement with literature values obtained from resistivity and heat capacity experiments. The experiment introduced students to cryogenic and computer data analysis techniques and forced them to extend their knowledge of the theory of electrical resistance and of characteristic temperatures.

A transverse beam profile monitor for p-p studies in the CERN SPS

In the SPS collider, counter-rotating beams of protons and antiprotons will be stored at 270 GeV/c for many hours. Each beam will consist of up to 6 bunches of 1011 particles. A simple device has been developed which allows the transverse profile of each individual bunch to be measured in an almost nondestructive way. 1,2,3). A fine beryllium wire is passed quickly (/spl I.itilde/4m/s) through the beam. The profile is measured by detecting the high-energy secondary particles produced in the wire. Due to the strong directionality of secondary particle production the profile of each proton and antiproton bunch can be measured simultaneously using two scintillators placed either side of the wire and close to the beam pipe. In addition, profiles of single beams can be obtained by measuring the secondary electron current emitted by the wire. The device has been successfully tested during storage studies with protons.

Properties of high-strength beryllium wire

1. The ultimate strength of beryllium wire with a purity of 99.96–99.99% is lower than that of wire from commercial beryllium; it increases from 54 to 90 kgf/mm2 as the diameter of the wire is reduced from 1.3 to 0.19 mm. The strength of annealed wire is independent of the diameter. The ductility is high for wire of high purity beryllium. 2. Mechanical stresses and plastic deformation of wire at 77°K induce relatively small changes in the specific electrical resistivity, which decreases with decreasing purity of the wire.

Recrystallization of beryllium wire

1. The effective activation energy of primary recrystallization and grain growth in beryllium wire of high purity is 18±3 kcal/mole and 49±3 kcal/mole, respectively. 2. The average rate of grain growth varies linearly with temperature and is 0.2·10−8 m/deg-sec and 0.006·10−8 m/deg-sec, respectively, which is two orders higher than for rolled beryllium and agrees with data for hydrostatically extruded beryllium.

Stress-Rupture of Epoxy-Coated Beryllium Wire

Stress-Rupture of Epoxy-Coated Beryllium Wire

Finite indentation of elastic-perfectly plastic membranes by a spherical indenter.

The beryllium wire epoxy composites displayed a yieldingtype tensile stress-strain curve with a proportional limit 30 to 40% of ultimate strength and yield strengths 80 to 96% of ultimate. In the 0-90° bidirectional composites tested in tension, there was 100% conversion of the strength and modulus of the beryllium wire. In compression, the beryllium wire plastic composites failed by plastic deformation, and in the long span flexure, they failed by excessive flexural deformation followed by filament fracture. Short beam interlaminar shear specimens failed by excessive flexural deformation rather than delamination. Inter laminar shear strength of the beryllium wire epoxy composites was not degraded by a two hour water boil. The ballistic impact resistance of beryllium wire epoxy composites was about 5 times that of glass fiber reinforced epoxy composites having similar lay up and thickness. V. Conclusions Based on preliminary processing and mechanical property investigations of plastic composites incorporating intermediate and high modulus graphite fibers, silicon carbide filaments and beryllium wire reinforcements, all three types of fibers warrant further investigation in composites for aerospace structural use. From the standpoint of further improvement, especially in modulus of elasticity, the graphite fiber composites have outstanding potential because of anticipated future availability of higher modulus graphite fibers.

Structural plastic composites incorporating new high modulus fibers.

Three types of high-modulus-to-density ratio fiber reinforcements which have recently been investigated in plastic composites by the Nonmetallic Materials Division of the Air Force Materials Laboratory are graphite, silicon carbide, and beryllium. Each of these types of fibers was used, separately, to fabricate laboratory scale unidirectional and multidirectional epoxy matrix plastic composites which were tested to determine their mechanical properties. The strength and modulus conversion of the fibers in the composites ranged from about 75 to 100%. Stress-strain curves for the graphite fiber and silicon carbide fiber composites, loaded parallel to the reinforcement direction, were essentially linear to fracture, whereas those for the beryllium wire composites showed considerable plastic deformation. In addition to static mechanical property data, some fatigue, stress-rupture, and ballistic impact data are also reported for some of the composites.

Wire Reinforced Metal Composites

The strength of a composite material will depend sensitively on that of the fibre chosen for reinforcement. Metallic and non-metallic whiskers can be very strong and other less strong, but more practical, fibres such as carbon, silica and boron are now available in experimental quantities. Some of the non-metallic whiskers, and the last three fibres mentioned, will no doubt eventually be made on a production scale.The strongest drawn wires yet available have tensile strengths of more than 0.5 X 106 psi which is still only one-third of that of iron or sapphire whiskers, and compares with boron in filament form, although the specific strength of the steel wire would only be one-third of the latter. On the basis of specific strength drawn beryllium wire would be only slightly better than the steel, but would have about 6 times its elastic modulus (E) which is comparable to that of boron.