RU2503494C2 - Device to strain conical specimens by shockwave and to preserve them after straining - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to testing of materials. Proposed device comprises collar ring 7 vertically fitted at base 12 to house mother ampoule with material specimen 11 to be tested by high dynamic pressure above which arranged is striker 5 composed of aluminium disc. Besides, it includes pyrotechnical charge to be initiated by trigger to produce detonation wave towards said disc. Guide steel ring 4 is arranged above said pyrotechnical charge 3 to accommodate said aluminium disc spaced from collar ring 7. Said mother ampoule is composed by base 8 and cover 9 jointed together by thread joint. Cylindrical recess for disc-shape insert 10 is made at ampoule base centre. Conical cavity is made at the centre of said recess to accommodate conical material specimen 11 to be tested. Specimen base is located flush with recess bottom surface while said insert 10 is arranged in cylindrical recess between cone base and ampoule cover 9. Specimen conical shape and ampoule design allows straining the specimens to over 2 Mbar using single detonator.

EFFECT: higher efficiency of testing.

5 dwg

Description

The invention relates to the field of testing materials and can be used for shock wave synthesis of new materials, shock wave compaction of powder materials, the study of phase transformations of various materials under the influence of high pressures and temperatures, and physical modeling of impact processes in laboratory conditions. In particular, the invention relates to the design of the device used in experiments related to loaded samples of graphite by a shock wave and their subsequent storage after loading.

Devices for shock-wave loading of samples with their subsequent preservation of various designs - with spherical geometry of loading, with flat geometry of loading, etc. - have similar applications: for shock-wave synthesis of new materials, modification of the structure and properties of materials, shock-wave compaction powder materials, studying the phase transformations of various materials under the influence of high pressures and temperatures, physical modeling of impact processes in laboratory conditions, etc. .P.

Devices with spherical loading geometry allow obtaining very high pressures (several Mbar in the central part), have an inhomogeneous spatial distribution of the maximum pressure and other loading parameters over the sample, require knowledge of the equation of state of the material under study and numerical calculations to establish the aforementioned pressure distribution and interpret experimental results have an extremely complex initiation scheme and are difficult to manufacture. In flat systems, the pressure is not high - usually up to 0.5 Mbar, but the initiation scheme is very simple (only one detonator is required), such devices are simple to manufacture, the pressure distribution over the sample is uniform to a first approximation, and mathematical modeling and knowledge to find the maximum pressure in the material no equation of state is required.

In particular, a device for processing materials with ultra-high pressure is known, which includes a single or multilayer spherical hermetic shell, in the central cavity of which a sample is placed in the form of a continuous ball of processed material for comprehensive compression so that the center of the sample coincides with the center of this cavity. At the same time, a layer of explosive is placed on the shell: the thickness, power and mass of which are calculated depending on what parameters (temperature, pressure) must be provided for a specific sample and specific material. An explosive layer activation system is installed on its surface, and the enclosure surrounds the layers described above, is single- or multi-layer and has the property to carry away excess momentum and absorb explosive energy by selecting materials or combining materials with certain properties that contribute to the absorption of energy generated by explosive substance (RU 2063449, C21D 7/00, B01J 3/06, publ. 10.07.1996).

The design flaw of such a spherical device is the laboriousness of its manufacture and the exceptional complexity of the explosive layer activation system, since with spherical blasting it is necessary to carry out multi-point initiation with a high degree of time synchronization and use elements of a special design to transmit detonation.

As mentioned above, devices with flat loading geometry are more convenient and technologically simple devices for conducting experiments on loading samples with a shock wave and then preserving them. Such devices are described, for example, in RU 2006137056 and in the article "Vladimir V. Milyavskiy, Konstantin V. Khishchenko, Tariana I. Borodina. Stepwise shock compression of C ₇₀ fullerene // Carbon. 2011. Vol.49. P. 2345-2351 "

So, in RU 2006137056, B01J 3/00 publ. 04/27/2008, a device for the synthesis of crystalline carbine is described, comprising a housing vertically mounted sequentially on the base with a chamber for storing a storage ampoule, in which graphite material is placed and above which a hammer in the form of a metal disk is placed, as well as a pyrotechnic charge with initiation from a detonator for the formation of a shock wave in the direction of the metal disk, a guide steel ring is installed under the explosive, in the cavity of which a hammer is placed in the form of an aluminum a disk, which is placed at a distance above the cavity formed by the ring-shaped steel element of the casing, in the cavity of which a steel storage ampoule is installed, made of the lower part (base) and the lid interconnected by a threaded connection, while an insert is placed in the internal volume of the storage ampoule in the form a steel disk with a cylindrical recess in the central part for installing a fluoroplastic disk in it with a diameter repeating the diameter of the cylindrical recess and the surface of which is across and lined with overlapping flakes of monochromatic quality graphite foil with a density of at least 2.2 g / cm ³ and a thickness of 10-20 μm, while after installing a fluoroplastic disk with flakes located on it overlapping relative to each other, the cylindrical recess is closed by another disk from ftoroplast and a copper stopper.

In this device, the pyrotechnic charge initiated by the detonator includes a plane shock wave generator of paraffin and explosive and the explosive itself. Adopted as a prototype.

The design described in RU 2006137056 is effective as a device for the synthesis of carbine, easy to manufacture, requires only one detonator to initiate, but in terms of maximum shock pressure acting on the sample, it is many times inferior to the spherical device RU 2063449.

The present invention is aimed at achieving a technical result, which consists in increasing the efficiency of the device in terms of carrying out the shock wave processing of the material placed in the device when the charge is initiated by one detonator by repeatedly increasing the maximum shock pressure acting on the sample by changing the geometry of the sample and its location. The specified technical result is achieved by the fact that in the device for loading the shock wave of conical-shaped samples and for preserving them after loading, containing a guard ring with a cavity vertically mounted sequentially on the base with a cavity for accommodating a storage ampoule in which a sample of material subjected to high dynamic pressure processing is placed ( or source material for shock wave synthesis, or powder material for conducting shock wave compaction) and over which a drummer in the form of an aluminum disk is placed, as well as a pyrotechnic charge with initiation from the detonator to form a detonation wave in the direction of this disk, a guide steel ring is installed under the explosive, in the cavity of which the specified disk is placed, which is located at a distance above the guard ring, in the cavity which has a steel storage ampoule made of interconnected by a threaded connection of the base of the ampoule and the covers covering it, in the upper part of the base of the ampoule a cylindrical recess for a steel liner in the form of a disk, a conical cavity is located in the center of the recess for accommodating a sample of the processed material in the form of a cone, the base of which is flush with the surface of the bottom of the recess, and a liner is placed in the cylindrical recess between the cone base and the lid of the ampoule in the form steel disk.

These features are significant and are interconnected with the formation of a stable set of essential features sufficient to obtain the desired technical result.

The present invention is illustrated by specific examples of execution, which are not only possible, but clearly demonstrate the ability to achieve the desired technical result.

Figure 1 presents a diagram of a device with a conical cavity for loading and preserving samples after exposure to a strong shock wave;

figure 2 is a General view of the ampoule of conservation and sample;

figure 3 - the results of a numerical calculation of the pressure distribution in the samples of graphites MF-307;

figure 4 - the results of a numerical calculation of the pressure distribution in the samples of graphite PGM;

figure 5 - the results of a numerical calculation of the pressure distribution in the graphite samples GMZ.

According to the present invention, there is considered a device (Fig. 1) for shock wave loading of graphite samples and for their conservation after loading. The sample for loading can be presented in the form of a monolithic element (as a graphite sample in the considered specific example) or in the form of a powdery material that is pressed directly into the conical cavity of the base of the storage ampoule. Also, samples from materials with a low melting point compared to steel can be made by melting the material and then pouring the melt into the conical cavity of the base of the storage ampoule.

Figure 1, the following positions represent the structural elements of the device: 1 - detonator; 2 - a plane shock wave generator; 3 - explosive; 4 - a directing ring; 5 - drummer; 6 - columns; 7 - a guard ring; 8 - the base of the conservation ampoule; 9 - ampoule cover; 10 - liner; 11 - test sample; 12 - base, 13 - cavity of conical shape.

This device contains a guard ring 7 vertically mounted sequentially on the base 12 with a cavity for storing the storage ampoule, in which the sample 11 is placed and above which the striker 5 in the form of a metal disk is placed, as well as a pyrotechnic charge (consisting of a plane shock wave generator 2 and an explosive 3) with initiation from detonator 1 to form a detonation wave in the direction of the metal disk. Under the explosive 3 is installed a guide steel ring 4, in the cavity of which is placed an impactor 5 in the form of an aluminum disk, which is placed at a distance above the guard ring 7, in the cavity of which there is a steel storage ampoule made of interconnected threaded connection of the base of the ampoule 8 and covering its cover 9, in the upper part of the base of the ampoule there is a cylindrical recess for the steel insert in the form of a disk 10, in the center of the recess there is a cavity of a conical shape 13 for placement of a sample of the processed material in the form of a cone 11, the base of which is flush with the surface of the bottom of the recess, and in the cylindrical recess between the base of the cone and the ampoule cover there is an insert in the form of a steel disk 10.

This device for loading conical-shaped samples by the shock wave and retaining them after loading allows obtaining high pressures (several Mbar at the top of the cone, as in devices with spherical loading geometry), is simple to manufacture, and has a simple initiation circuit from one detonator (as devices with flat loading geometry), has an inhomogeneous spatial distribution of the maximum pressure and other loading parameters along the sample, and require numerical calculations for the setup changes in the pressure distribution and interpretation of experimental results (as devices with spherical geometry). The advantage of this device compared to devices with a spherical loading geometry is a simple initiation scheme and ease of manufacture, compared with devices with a flat loading geometry - high loading pressures.

The device used a flat shock wave generator 2 (composition: P-1 paraffin (GOST 23683-89-150 g), explosive (composition A-IX-1, OST 384-636-72-150 g) and the explosive itself 3 (composition A-IX-1, OST 384-636-72-600 g).

To conduct shock-wave loading of graphite using this device, conical specimens with a diameter at the base of 15.346 mm, a height of 10 mm and an angle at the apex of 75 ° degrees were turned on a lathe using this device. Graphite of three different modifications was used as a starting material for research: GMZ (p = 1.70 g / cm ³ ), MPG-7 (p = 1.91 g / cm ³ ), and MF-307 (p-2.01 g / cm ³ ). Samples were placed in a conical cavity 13 of the corresponding size located in the base 8 of stainless steel 12X18H10T (Fig.2) with an outer diameter of 57 mm and a height of 20 mm. The cavity with the sample was covered with an insert 10 with a thickness of 3 mm and a diameter of 25 mm. A cap 9 with a thickness of 5 mm was screwed onto the base of the ampoule 8. The ampoule assembly was inserted into a steel guard ring 7 with an outer diameter of 150 mm and a thickness of 25 mm and was placed on a steel base 12 with a diameter of 150 mm and a thickness of 25 mm. The storage assemblies were loaded with a flat impact of aluminum plates 5 mm thick and 90 mm in diameter, dispersed by detonation products of the explosive to a speed of 3.35 km / s using an explosive throwing device.

After the experiment, conservation ampoules were opened on a lathe and stored samples were extracted from them, which were subsequently subjected to microstructural studies. Samples extracted from conservation ampoules were deformed to various degrees and lost their original regular conical shape, however, preserving integrity and a high degree of axial symmetry. The density of all samples was approximately the same and amounted to 2.1 g / cm ³ . Thus, the initially least dense GMZ graphite underwent the greatest deformation. The bases of the "cones" were slightly concave toward the apex. Each of the "cones" was cut into five layers perpendicular to the axis of symmetry. A powder sample was made from each layer of the material, which was studied by X-ray phase analysis in order to study the phase transformations of graphite under shock wave ™. The results of a numerical calculation of the pressure distribution in graphite samples MF-307, PGM and GMZ made using the state equation Khishchenko KV, Fortov VE, Lomonosov IV Multi-phase equation of state for carbon over wide range of temperatures and pressures // Int. J. Thermophys. 2005. V.26. 2. P.479 "are presented in figure 3, figure 4 and figure 5, respectively. These figures show the calculated isobars in loaded graphite samples nominated in GPa for three times t ₁ = 2.661, t ₂ = 2.712 and t ₃ = 2.858 μs corresponding to the maximum pressure in experiments with graphite MF-307, MPG and GMZ, respectively. For the initial moment of time in the calculations, the moment of contact of the drummer (position 5 in FIG. 1) with the cover of the storage ampoule (position 9 in FIG. 1) was taken. Thus, this device allows you to load samples with an impact pressure of more than 200 GPa.

The present invention is industrially applicable, can be manufactured using known technologies and materials. The novelty of the invention consists in a new sample form and a new design of the storage ampoule, which provides the possibility of loading the samples to pressures above 2 Mbar using a simple initiation scheme with one detonator.

Claims (1)

A device for loading the samples with a shock wave and for maintaining them after loading, characterized in that it contains a guard ring vertically mounted sequentially on the base with a cavity for storing a storage ampoule, in which a sample of material subjected to high dynamic pressure processing is placed, and above which a hammer is placed in the form of an aluminum disk, as well as a pyrotechnic charge with initiation from the detonator to form a detonation wave in the direction of this disk, under the explosive As a part of the pyrotechnic charge, a guide steel ring is installed, in the cavity of which the indicated disk is placed, which is placed at a distance above the guard ring, in the cavity of which there is a steel conservation ampoule made of threaded connections of the ampoule base and the covers that are connected to each other, in the upper part of the ampoule base a cylindrical recess is made for a steel liner in the form of a disk, characterized in that for loading the conical shape of the samples in the center of the recess Laga conically shaped cavity for receiving the sample material to be treated in the form of a cone, the base of which is located flush with the recess bottom surface and a cylindrical recess between the cone base and cover liner ampoules placed in a steel disc.

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