Method of making composite material. RU patent 2509818.

FIELD: metallurgy.

SUBSTANCE: hardening agent powder is prepared by mechanical doping of the mix of nanopowders of boron-bearing material in amount of 2-25 wt % of the mix for making composite and tungsten in amount of 1-30 wt % of said mix obtain composite powder mix of uniformity of 75-85 %. Powder of aluminium or its alloys is added to produced mix in amount of 100 wt % of aforesaid mix to go on with mechanical doping for 0.5-5 hours at the rate of 100-1000 rom. Obtained mix is degassed at 0.6-0.8 of aluminium fusion point, sintered and subjected to hot extrusion through die hole at 3000-15000 MPa at the press of capacity not lower than 500 t.

EFFECT: higher physical and mechanical properties, better operating characteristics, higher nuclear and ecological safety.

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The invention relates to the powder metallurgy, in particular the production of composite materials with metal matrix reinforced refractory filler, which can be used as structural materials in many areas of industry, such as medicine, chemistry, biochemistry, defense technology, protection of the environment, and especially in the nuclear industry for production of neutron-protective shields, in transport-packing containers (Tuk), neutron-absorbing walls in storage of fuel assemblies and spent nuclear fuel, as well as for biological protection of the personnel of the nuclear power plant and various sources of radioactivity.

The problem is that in the Russian Federation tuks are made of composite materials, the matrix which stainless steel reinforced boron-containing materials (see "Pulsed nuclear reactors RFNC-VNIITF. Begliarov, Avilkin, AppID etc. edited Avilkina. Snezhinsk, Izd-vo RFYaTs-VNIITF, 2002). Such containers are heavy and small download. Cost way of obtaining such a composite.

At present the foundry alloys borisovskogo aluminum [IAEA Regulations for the Transport of Radioactive Material - 1985 Edition (A mended 1990) Safety Series No 6 (Vienna: IAEA) (1990) Roland V. and Issard H. Use of Boron in Structural Material for Transport Packaging's. In Proc. PATRAM 95 Vegas has. December 1995. p 1455 (1996)]. However, the use of this material changes considerably the structure of mineral Fertilizers, which will require large expenditures.

The known method of manufacture metallotechnica composite, which in the preparation of reinforcing elements in the form of powder preparation matrix material in powder form, blending and mixing of powders and subsequent heat treatment of the mixture as a matrix material use nanopowder size 1-150 nm in the amount of 1-100 wt.% from the mass of matrix material; the mixing of powders is realized in the process of obtaining nanopowder matrix material; and the mixing of powders is realized in the preservative, and after mixing remove preservative vacuum; after receiving a mixture of powders process pressure of the mixture of magnetic-pulse pressing; after receiving a mixture of powders process pressure of the mixture explosive method; after magnetic pulse pressing handle the explosion, the pressure at processing explosion exceeds the pressure of magnetic-pulse pressing 1.1-20 times, and the rate of increase of the load - 1.1-10 times; after obtain a mixture of powders, it is heated to melting of the matrix material, and then obtained the suspension consisting of solid reinforcing elements and melted material matrix, mix and cool; if mixing suspension consisting of solid reinforcing particles and molten matrix material, in it add the powder material matrix. Provides increased durability and wear resistance of a composite (RF patent №2188248, CL SC 1/04, SS 1/10, publ. 2002).

This method has the following disadvantages: difficult to implement, as it includes many operations, magnetic-pulse pressing does not give a reliable pressure to get large pieces, and processing by the explosion, in addition, requires special conditions, special facilities, expensive equipment. The melting of the matrix and conservation procedure is unnecessary operations, which is a conglomeration of powders. That is the way and expensive, and difficult to produce.

Known composite material (options) and the manufacturing method, the essence of which is that composite the material includes as reinforcing filler glass and the binder - epoxy painting and fine-dispersed powder tungsten, with the filler impregnate binder, impregnated layers of filler collected in bags and placed on forming a frame. Received a blank form on the temperature-time mode thermosetting binders (see RF patent №2239895, CL G21F 1/10, publ. 2004).

However, structural strength and radiation-protective properties of the obtained material is insufficient for use as a construction material for Fertilizers. The way of its manufacture requires high culture of production, the technology is complex and requires much time.

Also known method of production of composite materials, which includes the mixture of ceramic filler and molten metal containing metal or item, which is the ion filler and/or substance, which is a reducing agent for filler. Using a filler with fine and coarse particles. Metal melt first mix with fine particles, and then with coarse. The second option of obtaining material is the impregnation of coarse particles metal melt, mixed with fine particles. The mixture is cooled to a hardening in the mold of a given shape. The technical result is the production of materials with a wide range of compositions and high operational properties (see Pat. The Russian Federation №2288964, CL SC 1/05, SW 35/653, B22F 3/26, publ. 2006).

However, this method requires for the exercise of its production of expensive raw materials, equipment and technology complex and has a high cost.

According to its technical nature and the result achieved by the proposal of the applicant, the closest one is the way to obtain a composite material with metal matrix reinforced refractory hardeners, including the preparation of a mixture of powder metal matrix with ceramic hardeners, briquetting mixture and hot extrusion of briquettes, which take concrete in the form of powder. The mixture of matrix metal and ceramic reinforcer before briquetting is subjected to mechanical alloying with obtaining composite pellets and further degassing in a vacuum at temperatures above solidus temperature matrix alloy, and as matrix metal choose metal from a group containing Al, Cu, Fe, Ti, Ni, or their alloys or their intermetallic compounds, and as ceramic reinforcer choose carbides, oxides, borides or nitrides with dispersion 1-20 microns (see Pat. The Russian Federation №2246379, CL B22F 3/20, publ. 2005).

This method is compared with the earlier, described above, is characterized by shorter cycle technology of its receipt, but he cannot provide the obtained material for manufacture of mineral Fertilizers required mechanical properties, as degassing composite pellets is carried out at a temperature above the solidus matrix alloy, i.e. high distribution of ceramic amplifier in metal matrix cannot achieve that bad effect on the mechanical properties of the material.

The way to obtain a composite material that is protected by the patent of the Russian Federation 2246379 chosen by the applicant for the prototype.

So as at present, the demand for Service is significantly increased, the task is to develop a cheap and simple way to obtain a composite material, which will have a low specific weight, high heat conductivity, high gamma and neutron absorptivity, high mechanical properties. It will allow to increase loading of containers without modification, and therefore significantly reduce the cost of transporting spent nuclear fuel from reactors and to increase safety of personnel and the environment.

Technical the result from the use of the invention consists in improving the physical, mechanical and performance properties required for the manufacture of Fertilizers composite material with a simple low-cost technology, which dramatically reduces the cost price of the material is obtained by a combination successfully selected and defined empirically composition of metals source material in a certain amount and a certain dimension, the procedure for mechanical alloying obtained composite mix and choice of the modes of operations performed during the entire process.

The above technical result is achieved by the method of obtaining composite materials, containing a matrix made of aluminium or alloys and ceramic reinforcer of boron-containing materials, mainly boron nitride or carbide of boron, includes preparation of the mixture of powder matrix metal with powder ceramic reinforces mechanical alloying to obtain a composite mixture, degassing cooked mixture in vacuum sintering and hot extrusion. According to the invention, in the beginning make a mixture of powder and ceramic reinforcer for what take 2-25 wt.% powder boron-containing material dimension of 1.0-100 nm in it enter 1-30 weight.% powder of tungsten of the same dimension and carry out mechanical alloying to obtain a composite mixture of concrete with a uniform 75-85%, then in the composition of the mixture is injected powder aluminum and its alloys dimension of 0.1-100 mm, forming a 100% wt. the composition of the initial powder mix of concrete and aluminium powder or its alloys, and continue mechanical alloying to the same uniform, which exercise within 0.5-5 hours with a speed of 100 to 1000 rpm, with degassing the composition of the mixture is carried out in vacuum at temperature (0,6-0,8) T PL melting point of aluminum is within 0,5-1,0 h, sintering carried out within 1-5 hours at a temperature of between 450 and 550 C and hot extrusion through the die plate perform under pressure 3000-15000 MPa on the press capacity not less than 500 tons

Conducting mechanical alloying is carried out in two stages: first, take 2-25 weight.% boron-containing material dimension of 1.0-100 nm, introducing him 1-30 weight.% Wolfram the same dimension and carry out mechanical alloying to obtain a composite mixture ceramic reinforcer uniformity 75-85%and then injected into this mix the powder aluminium and its alloys dimension of 0.1-100 mm, forming a 100% wt. the composition of the initial mixture of concrete and metal matrix, and continue mechanical alloying, within 0.5 - 5 hours with a speed of 100 to 1000 rpm that allows you to create the best conditions for excluding agglomerations composition of the mixture and improve mutual problems of adhesion, resulting in dramatically improved the structure of the obtained composite material, increases its density, homogeneity and material results in a high physical and mechanical properties, the same in all directions. Mode of mechanical alloying determined empirically of the terms of feasibility.

The combination in the structure of composite material for aluminium metal matrix in the form of powders specific dimension and nanoscale powders boron-containing materials and tungsten for ceramic reinforcer in certain amounts allowed to increase thermal conductivity, lower specific weight, to increase the mechanical properties, increase of gamma - and neutron-protective properties of the obtained material whose composition and modes of technological operations, as well as the order of their execution selected from the terms of feasibility, cost of the whole process and the composition of the material.

Execution degassing composition of the mixture at temperature (0,6-0,8) T PL melting point of aluminum is excluded the need formation of liquid metal, and, therefore, its saturation with gas from the environment, which also had a positive effect on the properties of the composite material, physical, mechanical, gamma and neutron radiation-protective properties of which are the same in all directions.

Modes degassing, sintering and extrusion through the die plate determined empirically on the basis of conditions of expediency and, like all other operations of the proposed method, selected from the best conditions possible, complete method in production conditions.

Signs stated in the claims, are necessary and sufficient to achieve the above technical result (in comparison with the prototype) - developed a new way to obtain a composite material with a matrix on the basis of aluminium and its alloys reinforced with a mixture of boron-containing material BN or 4 C and W, which significantly reduce the cost of production and to improve its physical, mechanical and performance properties.

Thus, the declared new technical solution of the set task.

The claimed solution meets all the criteria of patentability of the invention.

The presence of the distinctive features in relation to the selected prototype demonstrates the compliance of the technical solution the criterion of "novelty" under the current law. In the process of analysis of the modern technical level specified in the formula set of essential features is not revealed.

The invention meets the criterion of "inventive step", as for the specialist it is not obvious from the prior art. Moreover, the creation of such a method of obtaining a specific matrix of the composite for nuclear power production is necessary.

The invention is industrially applicable, as it can be used in industry. The claimed invention is characterized by specific features: new order operations of technological process (mechanical alloying in two stages), specific new composition of the initial materials in the form of nanosized ceramic powders reinforcer and powder matrix material, as well as a selection of experienced by their number, mode degassing received composition of the mixture, sintering, hot extrusion through the die plate and press capacity, each of which perform, reproduce, and not against the use in industrial environments.

Examples of the implementation of the declared method of obtaining composite materials, containing a matrix made of aluminium or alloys thereof, reinforced by concrete of boron-containing materials and tungsten in the form of nanoscale particles.

Example 1

Take 30 grams of powder carbide of boron (GOST 5744-85) dimension of the M5, go to sleep in grinding steel drum high-speed planetary mills Fritsch Pulverisette 5, which filled steel grinding bodies, produced by grinding of carbide of boron to the dimension of 1-100 nm. Then the obtained nanopowder boron carbide in the amount of 20 g is poured into the mixing agate drum mills Fritsch Pulverisette 5, add 10 g of nanopowder tungsten dimension less 68-90 nm produced by US Research Nanomaterials Inc., and produced by mechanical alloying up obtain a composite mixture with uniformity of 75-85%. Mechanical alloying of boron carbide and nanofiljtrami produced for 10 cycles: mixing-cooling, in the end, the total time of mechanical alloying amounted to not less than 30 minutes. After carrying out of this operation is received composite compound, which is in the mixing agate drum mills Fritsch Pulverisette 5 entered the aluminium powder or its alloy dimension of 0.1-100 microns in number 970 and continue mechanical alloying within 30 minutes with speed of rotation drove drum 100 rpm with repeated cycles: mixing-cooling. Then the prepared composition the mixture is placed in an aluminum ampoule and in the crystallizer implemented degassing in vacuum during 1 hour at temperature (0,6-0,8) the melting temperature used in the preparation of a mixture of aluminium and its alloys. The sintering process composite mixture occurs simultaneously with the degassing of this mixture. Then degassed and from composite sintered mixture press the workpiece is placed in the mold, the back wall which is Villeroy. The mold is placed on a horizontal press with a capacity of not less than 500 tons and under pressure 3000-15000 MPa provide extrusion press the procurement to obtain a work procurement of the required profile (cylinder, tube, strip and other). The power and pressure due to the weight, dimensions and mechanical properties of the material of press-preparation. After extrusion working harvesting took part 1 weight% nanofiljtrami, 2 weight% nanoscale boron carbide and 97% wt. aluminum and its alloy and the uniform distribution of the components have reached a 75-85%. The tensile strength of the material obtained was 350-450 MPa using powder aluminum alloy grades In 95; 300-400 MPa when using the aluminum powder AMg6 alloy grades, with significantly reduced weight and increased conductivity. This material has not only the best physical-mechanical properties, but also elevated radiation-protective characteristics: coefficient of absorption of neutron radiation increased 2-3 times compared to normal, and the scattering of gamma radiation has increased by 28-45%, which is confirmed by radiation testing this and other the samples by gamma and neutron radiation, held at the RRC "Kurchatov Institute".

Example 2

Take 200 grams of powder carbide of boron (GOST 5744-85) dimension of the M5, go to sleep in grinding steel drum high-speed planetary mills Fritsch Pulverisette 5, which filled steel grinding bodies, produced by grinding of carbide of boron to the dimension of 1-100 nm. Then the obtained nanopowder boron carbide in the amount of 180 g poured into the mixing agate drum mills Fritsch Pulverisette 5, add 120 g nanopowder tungsten dimension less 68-90 nm produced by US Research Nanomaterials Inc., and produced by mechanical alloying up obtain a composite mixture with uniformity of 75-85%. Mechanical alloying of boron carbide and nanofiljtrami produced within 10-15 cycles: mixing-cooling, in the end, the total time of mechanical alloying was at least 30-45 minutes. After carrying out this operation in the obtained composite compound, which is in the mixing agate drum mills Fritsch Pulverisette 5 entered the aluminium powder or its alloy dimension of 0.1-100 microns in the amount of 700 g and continue mechanical alloying within 60-90 minutes with speed of rotation drove drum 100 rpm with multiple cycles: mixing-cooling. Then the prepared composition the mixture is placed in an aluminum ampoule and in the crystallizer provide in vacuum degassing for 2 hours at temperature (0,6-0,8) the melting temperature used in the preparation of a mixture of aluminium and its alloys. The sintering process composite mixture occurs simultaneously with the degassing of this mixture. Then degassed and from composite sintered mixture press the workpiece is placed in the mold, the back wall which is Villeroy. The mold is placed on a horizontal press with a capacity of about 1200 ton and under pressure 3000-15000 MPa provide extrusion press the procurement to obtain a work procurement of the required profile (page, see photo). The power and pressure due to the weight, dimensions and mechanical properties of the material of press-preparation. After extrusion working procurement had 12% wt. nanofiljtrami, 18% wt. nanoscale boron carbide and 70% wt. aluminum and its alloy and the uniform distribution of the components have reached a 75-85%. The tensile strength of the material obtained was 500-600 MPa using powder aluminum alloy grades In 95; 650-700 MPa when using the aluminum powder AMg6 alloy grades, with reduced weight and increased conductivity. This material is not only the best physical-mechanical properties, but also elevated radiation-protective characteristics: coefficient of absorption of neutron radiation has increased by 6-10 times the normal and scattering of gamma radiation has increased by 48-73%, which is confirmed by radiation testing this and other samples by gamma and neutron radiation, held at the RRC "Kurchatov Institute".

In addition, the sample was made other flat samples of composite claimed composition stated in the way the system: (B95+B 4 C n+m +W n and AMG6+BN n+m +W n ), examination of which has also confirmed the above physical-mechanical properties and radiation indicators.

Thus, the task of developing a cheap and simple way of obtaining material for manufacture of mineral Fertilizers solved. Received metallogidridnyh composite, compared with the prototype with a higher physico-mechanical properties at low production cost.

This result achieved by the definition of experienced by the best combination of the selected structure of a composite material in the form of nanosized ceramic powders reinforcer boron nitride or carbide of boron and tungsten & powders matrix with two-stage mechanical alloying, production of composite mixes and compilations of the best combination of modes of their further processing at the industrial equipment.

On results of the proposed technical solutions of the obtained metallotechnica composite developed design TUK-84 and compared with the currently in the Fat of it enabled to reduce the weight of each Fat by 20-30%, which increases its load by 10-30%, that considerably will reduce the need Park Fat, and consequently, the cost of maintenance. Improved operational properties of mineral Fertilizers: they are more durable, lighter, stiffer and more neutron-protective, increasing nuclear and environmental safety and improve working conditions of maintenance personnel during storage and during transportation.

Thus, the proposed method industrial feasible, and the resulting material is industrially applicable.