RU2844587C1 - Method of producing workpiece of composite aluminium-matrix armoured plates - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, particularly, to production of armoured plates. Proposed method of producing workpiece of composite aluminium-matrix armoured plates comprises preparing charge in mixer, producing melt therefrom on metal base in furnace with introduction of disperse particles, placing melt with particles in vessel, cooling melt with particles to solid state and withdrawing it from vessel. Charge is prepared on the basis of aluminium with addition of refractory disperse particles by means of mixer. Molten metal of the second part of aluminium or aluminium alloy, for example, consisting of 96 % of aluminium and 4 % of silicon, is prepared by means of heating in the furnace. Charge is added to molten aluminium or aluminium alloy with simultaneous or subsequent introduction of refractory disperse particles into liquid body of metal behind its mirror by mixing of molten metal. Then, the rotation mode of the rotor of the horizontal centrifugal casting machine is switched on and the melt with refractory dispersion particles is loaded from the crucible into the rotor mould by means of a loading container and/or a chute of the said machine. Sleeve is formed in rotor to make said workpiece with wall thickness at its centre making, at least, 7 mm, with concentration of particles, mainly, in its surface layer and uniform distribution over outer cylindrical surface. Then cooling the centrifugal machine rotor mould to the formed bushing solid state, stopping the centrifugal machine rotor rotation, sleeve is withdrawn from rotary machine rotor mould to cut the workpiece and machine it to production of armoured plates.

EFFECT: invention allows obtaining workpiece with structure recommended for armoured plates.

6 cl, 4 dwg, 1 tbl

Description

The invention relates to metallurgical production, with the production (preparation, manufacturing) of cast and deformable composite materials in the form of metal matrices with inclusions of many solid particles and in the form of a blank for subsequent manufacturing, by mechanical processing of the blank, armor plates or other means of armor protection.

Both homogeneous and heterogeneous armor are known, including in the form of composite aluminum-matrix (based on aluminum alloys) armor plates with solid particles (inclusions) insoluble in aluminum-based melt in the volume of the matrix [1. Artsruni A.A. (JSC "Research Institute of Steel"). Russian aluminum tank armor and foreign analogues // Army, No. 1, 2022. - URL: http://орр.gp-media.ru/2022/03/21/россияющая-алюбления-танковая-бро/?ysclid=m4721ck9b986013698 (date of access 12/29/2024);

2. Modern armor based on composite materials. Homogeneous and composite armor… - URL: https://ezoteriker.ru/sovremennaya-bronya-na-osnove-kompozitnyh-materialov-gomogennaya-i/ (date of access 12/29/2024);

3. Aluminum armor alloys in extreme conditions of use. - URL: https://www.niistali.ru/about-company/stati-nashikh-avtorov/alyuminievye-bronevye-splavy/ (date of access 12/29/2024)].

Such armor has a number of advantages and therefore has found application in armored vehicles (armored cars, bulletproof vests, etc.). However, its wider application, in competition with composite layered and other designs [4. RU 2831691 C1, IPC F41H 1/00, JSC NPO Spetsmaterialov, published 12/11/2024 "Method for producing a high-density composite for armor protection"] is constrained by the technological difficulties of forming specified rational (in terms of armor resistance and other properties) structures with the required distribution of dispersed particles differentiated by the volume of the matrix.

A number of foreign companies have mastered the industrial production of aluminum matrix composites (the best known ones are shown in Table 1).

Centrifugal casting machines of horizontal type are known (since the beginning of the 20th century) [5. Horizontal machines for centrifugal casting of metal blanks: operating principle and review of 3 models. - URL: https.//eurasia-group.ru/blog/articles/gorizontalnye-mashiny-tsentrobezhnogo-litya-zagotovok-iz-metalla-printsip-deystviya-i-obzor-3-modele/?ysclid=m4jufx32qs42121867 (date of access 12/28/2024); 6. Centrifugal casting machines with horizontal axis. - URL: https://aitcom.ru/litejnoe-i-formovochnoe-oborudovanie/mashinyi-czentrobezlmogo-litya/mashinyi-czentrobezhnogo-litya-s-gorizontalnoj-osyu?ysclid=m4julguibm806661908 (date of access 12/28/2024); 7. Matveenko I.V. and Tarsky V.L. Equipment of foundries. Textbook for technical schools. Moscow, "Mashinostroenie", 1976, 440 p., ill. (Chapter 2 "Machines for centrifugal casting", paragraph 2 "Centrifugal machines with a horizontal axis of rotation". - Pp. 249-251)].

However, these sources are dedicated specifically to equipment and tooling, but not to the products themselves.

Centrifugal casting is a technology that allows the creation of hollow round products (in particular, in the form of a cylinder) from steel, cast iron, copper or aluminum alloys). Due to the gravitational and, mainly, centrifugal forces acting on the melt, it is possible to obtain a high-quality casting, characterized by a minimum of local voids, gas cavities and other similar defects in comparison with other casting methods.

However, centrifugal casting requires appropriate, relatively complex equipment and has limitations in terms of the possible shapes of the blanks.

Among the analogues of the claimed invention, using a centrifuge in the formation of composites with localization of individual layers, are known "Method for producing an armor-protective structure based on porous aluminum with a localized compaction volume" [8. RU 2686501 C1, IPC C25D 11/04, F41H 5/00, published. 04/29/2019, author I. Vorobyev; patent holder Central Research Institute of Engineering Troops of the Ministry of Defense of the Russian Federation]; 9. Aluminum armor is no joke. The combination of metal with its oxide produces a lightweight and durable material. - URL: https://www.kommersant.ru/doc/3968008 (date of publication 05/16/2019, date of access 12/29/2024].

In an analogous method, a porous aluminum blank is made in the shape of the protected object. Then the aluminum is converted into an oxide, which is close in hardness to corundum, i.e., single-crystal aluminum oxide. The under-oxidized aluminum matrix ensures the plasticity of the material. The porous aluminum oxide composite is lightweight and has high impact strength.

In a similar method, armor is made in four stages.

The first is mechanical processing of a porous aluminum blank and giving it the required shape. The thickness of the plate depends on the specified durability criteria, but cannot be less than 10 mm. On one of the end faces of the plate blank, a protrusion of at least 50 mm in height with a cross-section in the form of a circle is designed and turned in advance. The diameter of the circle corresponds to the thickness of the plate. The profile serves as a current conductor and a hydraulic conduit for supplying electric current and electrolyte.

At the second stage, the molded porous aluminum blank with a protrusion is placed in a centrifuge. Then a spongy soft material (felt or foam rubber), identical in shape to the blank and impregnated with a liquid hydrophobic dielectric polymer, is attached to the blank from the side not intended for oxidation. In the centrifuge, under the action of centrifugal forces, the liquid hydrophobic dielectric polymer flows from the spongy material into the body of the blank. At the same time, the blanks are heated in the centrifuge. The polymer hardens at a given thickness of the blank. This is how the boundary of the volume is formed, which will then be subjected to microarc oxidation.

At the third stage, the workpieces processed in the centrifuge are placed in the oxidation unit. In the bath of the unit, the part of the workpiece where the dielectric is applied will not participate in the electrochemical oxidation reaction, the rest will turn into a hardened layer of aluminum oxide.

At the fourth stage, the blanks undergo mechanical processing, during which the mentioned protrusions are removed.

The described analogue, however, is interesting here only in that it uses a centrifuge for local introduction of a liquid substance (polymer) into an aluminum matrix.

A method is known for producing a neutron-absorbing material based on aluminum, containing layers with different concentrations of boron carbide, including the production of flat plates of an aluminum alloy with silicon and dispersed particles of boron carbide with a size of 10-30 μm in a concentration of 10-55 mass %, with the effect of vibration, when, as a result of the latter, boron carbide particles float up in the aluminum alloy melt and enrich the upper layer with them [10. DE 102011120988 A1, IPC C22C 21/02, published 13.06.2013].

However, this method does not allow obtaining large blanks, and vibration, "by definition", assumes opposite inertial forces of action on solid dispersed particles introduced into the melt (up-down movement), which in principle cannot provide high layer-by-layer differentiation of the concentration (content) of dispersed particles in the melt. And in general, it is devoted to solving another problem - obtaining effective protective materials from radiation.

An even closer analogue can be considered a method for producing a neutron-absorbing material based on aluminum containing layers with boron carbide, which uses a horizontal centrifugal casting machine and forms a multilayer (“wafer” structure) sleeve-blank in it by sequentially forming (with hardening) and leaving in the mold) concentric layers-sleeves, with alternating layers without dispersed particles and with dispersed particles of high concentration [11. RU 2693669 C1, IPC C22C 21/00, C22C 1/10, JSC VPO VNIIMASH, published 03.07.2019].

However, firstly, in thin layers with a high concentration of dispersed particles, the latter will be distributed almost uniformly during the rotation of the mold (and nothing else is required with such layer-by-layer formation of bushings). At the same time, the outer layer does not contain dispersed particles. Secondly, the integrity of the aluminum matrix is, in principle, violated. Thirdly, the implementation of the method is technically difficult, since boron carbide wets liquid aluminum only at a temperature of more than 950 ° C. Fourthly, as with the previous analogue, problems are solved that differ from those set by the authors of the claimed invention.

The closest analogue (adopted as a prototype) of the claimed method in terms of purpose and a set of essential features is a method for producing a blank of composite armor plates, preparing a charge in a mixer, obtaining a melt from it on a metal base in a furnace with the introduction of dispersed particles that retain their solid state in the melt, placing the melt with dispersed particles in a container in the shape of the said blank, forced movement of the dispersed particles in the said melt to a given distribution over its volume, cooling the melt with dispersed particles to a solid state and, as a finishing operation, removing it from the container with the possibility of subsequent cutting and mechanical processing to form armor plates [12. RU 94005166 A dated 14.02.1994, IPC C21C 1/10, published 20.10.1995, author - Semenov B.I., applicant - Moscow Institute of Instrument Engineering]. In the prototype method:

obtained in a crucible by heating a melt on a metal base (metal matrix) in a furnace, with the introduction of dispersed (ceramic) particles into it,

the melt is mixed with dispersed particles using a disk mixer, fixed on the drive shaft with the possibility of reciprocating movement in the vertical plane,

wherein the crucible, furnace and stirrer with its drive are used as part of a unit designed for this purpose,

in which, due to mixing and the gravitational field, a melt is formed with dispersed particles redistributed in its volume (in the matrix),

pour the contents of the crucible into a molding container (according to the shape of the workpiece),

cool and remove the resulting workpiece.

In this case, the matrix acquires the required finishing structure.

However, the prototype method, despite all its positive characteristics, is limited in its capabilities.

The problem is the complexity, if not the impossibility, of using known methods, including the prototype method, to effectively introduce dispersed particles into the aluminum matrix and, moreover, to obtain an aluminum matrix structure with the outer surface layer of the armor plate (and therefore the blanks for such plates) maximally saturated with these particles, and with a uniform distribution of particles over the surface of this layer (at any depth).

Accordingly, the authors of the claimed invention have set the task of obtaining a blank of composite aluminum matrix armor plates with a structure recommended (in terms of armor resistance) for armor protection means, characterized by a predominant concentration of refractory dispersed particles (RDP) in the surface layer of the aluminum matrix, uniformly over the area of the outer claimed cylindrical surface (the expected technical result of the invention), with additional compaction of the aluminum matrix material over the entire volume of the blank (the expected accompanying technical result, known in comparison with the centrifugal casting method in general and new in comparison with the prototype method).

The solution to the said problem is achieved by the fact that in the method for producing a blank of aluminum matrix composite armor plates, including the preparation of a charge in a mixer, obtaining from it in a furnace a melt on a metal base with the introduction of dispersed particles that retain their solid state in the melt, placing the melt with dispersed particles in a container in the shape of the said blank, forced movement of the dispersed particles in the said melt to a specified distribution over its volume, cooling the melt with dispersed particles to a solid state and, as a finishing operation, removing it from the container with the possibility of subsequent cutting and mechanical processing until the formation of armor plates, according to the claimed invention,

the charge is prepared on the basis of aluminum in the form of, for example, grits or shavings with the addition of refractory dispersed particles (RDP), wetted by the melt and retaining their solid state in the melt, using a mixer, for example an attritor or mill, until a homogeneous mechanical mixture is formed - a premix,

prepare by heating in a furnace a melt of the second part of aluminum or an aluminum alloy, for example, a composition of 96% aluminum and 4% silicon,

the charge is added to the aluminum or aluminum alloy melt without removing the two components for the specified combination, with the simultaneous or subsequent introduction of the TDC under the metal mirror, and the melt is stirred, for example, with a stirrer, until a uniform distribution of all components is obtained throughout the volume of the melt,

the rotation mode of the rotor of the horizontal centrifugal casting machine is switched on and the melt with the TDC is loaded from the crucible into the rotor mold by means of the loading container and/or chute of the said machine,

due to the previous operation and, mainly, centrifugal forces in the rotor, a bushing is formed as the mentioned blank with a wall thickness in its middle of at least 7 mm, with the concentration of TDC mainly in its surface layer and uniform distribution over the area of the outer cylindrical surface,

cool the mold of the centrifugal machine rotor until the formed sleeve is in a solid state,

stop the rotation of the rotor of the centrifugal machine,

the sleeve is removed from the mold of the centrifugal machine rotor with the possibility of subsequent cutting of the workpiece and mechanical processing until the formation of armor plates.

In addition, the stated goal is achieved due to a number of additional (dependent, not mandatory, but recommended as rational) features of the claimed method, namely:

- between the above-mentioned operations of preparing the batch and adding it to the aluminum-based melt, the batch can be pressed, with the possibility of compaction (this allows not only more rational use of the working volume of the crucible, but also reduces the risk of oxidation of the metal forming the aluminum matrix, avoids coagulation of the TCD and simplifies the process of introducing the TCD in comparison with alternative methods);

- TDC can be introduced in quantities from 3 to 15 mass % (the lower limit is determined by achieving a noticeable level of increase in mechanical properties that determine the level of armor resistance, and the upper limit is determined by the ability of the melt to fill the casting mold);

with any of the three sets of features listed above

- oxides, such as aluminum oxide AL2O3, with a size of up to 20 µm, can be used as TDCs (this is an alternative to the previous special case, which additionally allows for a reduction in costs);

- carbides, such as silicon carbide SiC, with a size of up to 20 µm, can be used as TDC (this is an alternative to the previous special case, which additionally allows for good technological machinability of the resulting blanks of composite aluminum matrix armor plates);

- borides can be used as TDCs, for example titanium boride TiB ₂ or zirconium boride ZrB ₂ , with a size of up to 20 µm (this is an alternative to the previous special case, which additionally allows for an increase in the level of mechanical properties of the composite material due to the almost complete resistance of borides to molten aluminum).

Among the known methods and descriptions of the operation of devices, none have been found whose set of essential features would coincide with the declared one. At the same time, it is due to the latter that a new technical result is achieved in accordance with the task set.

A clear distinction between the restrictive and distinctive parts of the given sets of essential features, reflecting the results of a comparative analysis of the claimed method with the prototype, is related to the world level of novelty of the technical solution. The world level of novelty is the first of the triad of features (criteria) of the invention.

Further, the set of distinctive essential features of the claimed method is not a simple sum of known technical results of the application of separately known operations - "components" of the method. There is "emergence", that is, a "super-effect" (in the patent meaning of this term), which was not obvious to a specialist from the achieved level of technology/technical equipment, of course, before considering the claimed technical solution. With a range of additional technological and technical-operational advantages and possibilities. This convincingly demonstrates the inventive level of development as the second of the triad of qualifying features of an invention.

The third qualifying feature, industrial applicability, is also indisputable and follows, first of all, from the fame and practical use in the foundry business of horizontal centrifugal casting machines, experience in obtaining aluminum matrices and obtaining composites based on them.

To implement the claimed method, no new device (new devices) is required, since known devices are sufficient, the main one of which is a horizontal centrifugal casting machine, repeatedly mentioned above in the text and additionally - further in the text.

The claimed method is described below with illustrations in Fig. 1-4: Fig. 1 schematically shows the process of loading a charge (premix) into a crucible, previously prepared from particles (granules or chips) of an aluminum alloy and TDC (in a solid state by mixing followed by compacting pressing), and installing the crucible in an induction furnace, where 1 is a crucible, 2 are the turns of the furnace inductor, 3 is a metal melt (aluminum or aluminum alloy), 4 is a premix containing TDC;

Fig. 2 shows the process of obtaining, in a crucible installed in an induction furnace, with the contents of the crucible being stirred with a stirrer, molten aluminum or an aluminum alloy, with the inclusion of TDC from the said batch (premix), where 1 is the crucible, 2 are the turns of the furnace inductor, 4 is the partially melted premix containing TDC, 5 is the melt, 6 is the stirrer;

Fig. 3 shows the process of forming the final product of the method - a composite sleeve-blank from a melt based on aluminum or an aluminum alloy, with the inclusion of TDC, prepared according to Fig. 2, loaded into the mold of a horizontal centrifugal casting machine, with subsequent cooling in the mold and the final formation of the aluminum matrix with the TDC in it, where n is the angular velocity (number of revolutions) of the machine rotor; 1 - crucible, 5 - melt with TDC, 7 - rotor, 8 - mold, 9 - loading container of the machine, 10 - trough, 11-13 - elements of the rotor mold (11 - insert, 12 - front cover, 13 - rear cover);

Fig. 4 shows the final product of the method - a sleeve-blank that has hardened as a result of cooling and been removed from the chill mold of the casting machine, in longitudinal section, with a conventional image of the layer of predominant filling of the aluminum matrix with TDC, where h is the thickness of the surface layer of predominant filling (concentration) of TDC; 14 - sleeve-blank, 15 - outer surface of the sleeve-blank, 16 - inner surface of the sleeve-blank, 17 - TDC in the aluminum matrix.

To implement the claimed method, it is possible to use equipment, including a horizontal centrifugal casting machine, and tooling, both known and used in the foundry industry (see, for example, [5, 6]), and newly created.

The claimed method for producing a blank of aluminum matrix composite armor plates includes the following sequence of operations with material means on material objects:

The first operation: prepare a charge based on aluminum with possible additives (including metallic ones) in the form of, for example, grits or shavings with the addition of refractory dispersed particles (RDP), wetted by the melt and retaining their solid state in the melt of the said first part of aluminum or aluminum alloy. This is done in a mixer (by means of a mixer), for example, in an attritor or mill, until a homogeneous mechanical mixture - premix - is formed.

Illustrations for this operation are not given due to the sufficiency of the textual presentation for understanding. However, the charge (premix) is shown in the upper part of Fig. 1 (pos. 4), and according to the particular implementation of the method recommended by the authors - with final pressing in the press (compacting), which will be discussed in more detail below in the text in the description of additional features of the method.

The predominant characteristic size of the mentioned TDCs is up to 20 µm (see below in the text the recommended particular chemical composition of the said particles, with a melting point higher than the maximum temperature of the liquid aluminum matrix) and in an amount of 3 to 15 mass. %, which, accordingly, retain their solid state in the melt at all stages of the method (see Figs. 1-3) and, especially, in the final (hardened) aluminum matrix (see Fig. 4). The characteristic size of the TDCs is determined, to a large extent, by the method of their production.

The result of the first operation in relation to the second operation can be called a “pre-prepared charge (premix), which generally includes (let us repeat) the TDC (main component) plus aluminum or aluminum alloy (the first part, taking into account the subsequent operation).

Second operation: prepare a melt of the second part of aluminum or aluminum alloy (pos. 3 in Fig. 1).

In this case, the said second part 3 together with the said first part (in the structure of the charge 4) of the metal constitute the total specified quantitative (mass or volume) content of the future aluminum matrix (i.e., the matrix based on aluminum) in the composition of the final product of the method - the blank of composite aluminum matrix armor plates.

In addition, the first and second parts of the metal components may be the same or different in chemical composition. But in any case, they are based on aluminum, which is why the industry-accepted term "aluminum matrix" is used.

In the second operation (see also Fig. 1), aluminum or aluminum alloy (generally speaking, “aluminum-based”) is placed in crucible 1 and melted by heating in an induction (see Fig. 1, pos. 2) or other furnace, ensuring that the melt temperature is not lower than the melting point of aluminum or aluminum alloy, respectively, that is, the second part of the metal is melted (the liquid state of the second part of the aluminum or aluminum alloy is ensured).

Induction type furnace has many advantages and is most widely used in foundry industry.

Chronologically, the first and second operations can be done either one after the other (including with a break), or with some (depending on the specific situation) overlap in time. The main thing is to have both products available at the beginning of the third operation, respectively, the charge (premix) 4 and the melt 3 (see Fig. 1) of the second part of the metal.

Note on the term "aluminium-based alloy" ("aluminium alloy"): here it may be, for example, in the composition: 96% aluminium and 4% silicon. The alloy grade AL5 has an average chemical composition of 5% silicon, 0.4% magnesium, 1.25%) copper, the rest is aluminium, melting point is 620°C, recommended pouring temperature is 720-740°C.

Third operation: the charge (premix) 4 is added to the melt of aluminum or aluminum alloy 3 (in other words, to the melt of the second part 3 of the metal, see Fig. 1 taking into account the arrow, without removing it from the operating (power supply of the inductor 2) furnace or temporarily removing it for the specified unification of the two components), with the simultaneous or subsequent introduction of the TDC under the mirror of the metal 3 (which is a resistance to introduction due to the significant surface tension of the oxide film of aluminum), and the melt 5 is stirred (based on the aforementioned melt 3 of the first part of the metal), for example, with a stirrer 6 (the movements of which are shown by arrows, see Fig. 2) until a uniform distribution (the degree of uniformity is set depending on the specific situation) of all components is obtained throughout the volume of the melt. As a result, the new melt becomes an incomplete aluminum matrix 6, which is in a liquid-flowing state (see Fig. 3).

In other words, the first (solid, premix) component 4 and the second (liquid, melt) component (see Fig. 2) are combined in a crucible and, while mixing, the melting process is continued. The TDC is distributed throughout the melt volume by mixing, melting and dissolving the metal contained in the charge (premix). Until a liquid intermediate product 5 (see Fig. 3) of the method (technological process) is obtained at the end of the operation, as the next step in the formation of the aluminum matrix (see Fig. 2).

It is desirable to ensure the content of TDC in the premix at the highest possible level, which is limited by technological reasons (according to the particular version of the method recommended by the authors - the possibility of final pressing in a press). A high level of TDC content allows to significantly increase the efficiency of obtaining an intermediate product similar to the use of ligature in metallurgy. The required amount of premix can be prepared (and introduced) into the liquid melt in portions. This allows to use less powerful pressing equipment and simplify the melting process: to prevent cooling of the melt during the melting of a separate portion of the premix. In some cases, mainly depending on the duration of the operations associated with melting, measures may be required to protect the melt from interaction with the surrounding atmosphere, for example, the use of an inert gas.

Fourth operation: the rotation mode (angular velocity n) of the rotor 7 of the horizontal type centrifugal casting machine is switched on (see Fig. 3) and the melt with the TDC (in aggregate - the liquid body 5) is loaded (pouring) from the crucible 1 into the mold 8 of the rotor 7 by means of the loading container 9 and/or the chute 10 of the specified machine.

Fifth operation: due to the fourth operation and, mainly, the centrifugal forces in the rotor 7, a bushing is formed as the mentioned blank with a wall thickness (between the outer 15 and inner 16 surfaces) in its middle of at least 7 mm, with a concentration of particles (the main thing!) mainly in its surface layer and uniform distribution over the area of the outer cylindrical surface 15 (layer of thickness h - see Fig. 4).

The control of the said formation of the sleeve 14 consists mainly in setting/controlling the speed of rotation of the rotor 7 and the duration of the fifth operation.

Sixth operation: cool the mold 8 of the rotor 7 of the centrifugal machine until the formed sleeve 14 is in a solid state.

Seventh operation: stop the rotation of rotor 7 of the centrifugal machine.

Eighth operation: the sleeve 14 is removed from the mold 8 of the rotor 7 of the centrifugal machine (using, as a rule, a device provided with the machine, and the removal itself is facilitated by the taper of the inner wall of the insert 11 and the axial mobility of its rear wall 13).

With the proviso (in terms of fulfilling the requirement of uniformity of terminology) that all components participating in the method (technological process) form an “aluminum matrix” at the moment of completion of the mentioned processes of melting, dissolution and mixing in the crucible, the formation of a solid cooled (i.e. before removal from the mold 8) sleeve-blank 14 (see Fig. 4).

As a special case of the method, the following is possible and recommended as rational: between the mentioned operations of preparing the charge (premix) 4 and adding it (him) to the aluminum-based melt, the charge (premix) 4 is pressed (by means of a press), with the possibility of compaction (which is more rational from the standpoint of using the working volumes of the crucible 1, press and mold 8).

TDC can be introduced, preferably, in an amount of 3 to 15% by weight.

At high (estimated to exceed 10% by weight content of TDC 17 in the composite material) the batch 4 itself can be the entire initial material (i.e. the previously mentioned “second part of the metal” is not provided). In this case, its (4) elemental composition should coincide with the elemental composition of the composite (5, 14).

Let us consider a specific example of the implementation of the claimed method.

A charge based on aluminum (grains of the AKP brand containing at least 96% of the base metal, with granule sizes of 2-5 mm, manufactured by KMK LLC, TU 1791-002-4735049-2004) weighing 700 g was prepared, with the addition of refractory dispersed particles (RDP) of SiC with a characteristic size of 20 μm on average, in an amount of 300 g. Taking into account the fundamental wettability of the latter by the melt and their ability to maintain their solid state in the melt of the said portion of aluminum. The charge was prepared in the mill available to the Applicant until a homogeneous mechanical mixture - premix - was formed. A microscope was used to control the grinding process.

The charge (premix) was pressed (using a press, also available to the Applicant) before compaction (due to the rational nomenclature of crucibles, press and mould available to the Applicant). A total of 10 pressed parts of the premix were prepared in the form of cylinders weighing approximately 100 g, each part containing 30 g of TDC.

A melt of the second part of aluminum weighing 1000 g was prepared, which, together with the first part (in the structure of the charge) of the metal, made up the total quantitative (volume) content of the future aluminum matrix. This ensured the calculated mass content (the ratio of the mass of the TDC to the calculated total mass of the obtained material) of 15% (the ratio of the mass of the TDC to the mass of aluminum used to obtain the premix is 42.9%, and the ratio of the mass of the TDC to the mass of aluminum contained in the aluminum matrix is 17.6%).

The aluminum was placed in a crucible and melted by heating in an induction furnace (also available in the Applicant’s foundry) to a temperature of 720°C (with a reserve to compensate for cooling from the supplied premix).

The first (solid, premix) component and the second (liquid, melt) component were combined in a crucible, adding the premix in portions and stirring with a stirrer (from the Applicant's arsenal), distributing the TDC uniformly throughout the melt volume (due to stirring, melting and dissolving the metal contained in the charge). At the end of the operation, a liquid intermediate product was obtained, the next step in the formation of the aluminum matrix.

The rotation mode of the rotor of the horizontal centrifugal casting machine (available to the Applicant's counterparty) was switched on and the melt with the TDC (collectively, the liquid body) was loaded from the crucible into the rotor mold by means of the loading container and the machine chute. The diameter of the mold was 215 mm, the length was 250 mm.

Due to the previous operation and centrifugal forces in the rotor, a sleeve was formed as the mentioned blank,

The mold was cooled until the formed sleeve was in a solid state, the rotation of the rotor was stopped, and the sleeve was removed from the mold using the device provided with the machine and the movable wall of the machine.

We measured the outer and inner diameters in the middle part of the sleeve length and subtracted the other value from one, thereby determining the average thickness of the sleeve wall (it turned out to be 8.5 mm). By selecting (setting and monitoring) the rotor rotation mode (speed and duration of the centrifugation operation), it is possible, if necessary, to adjust the obtained thickness of 8.5 mm to a smaller or larger side in the declared range of recommended thicknesses.

The sleeve (with a diamond-containing disk) was cut longitudinally and the structure of the cut in the sleeve fragment was studied under a microscope.

The concentration of particles was found to be predominantly in its surface layer and fairly uniform (even) in distribution over the area of the outer cylindrical surface.

Which is what was required.

After this, the experiment was repeated experimentally on the same equipment and with the same participants in the experiment, with a TDC quantity of 3 mass %, i.e. the minimum of the declared range, all other things being equal. Similar premix pressings were used in the form of cylinders weighing about 100 g, each part of which contained 30 g of TDC in the amount of two.

A melt of the second part of aluminum weighing 1800 g was prepared, which, together with the first part (in the structure of the charge) of the metal, made up the total quantitative (volume) content of the future aluminum matrix. This provided the calculated mass content (the ratio of the mass of the TDC to the calculated total mass of the obtained material) of 3%. (The ratio of the mass of the TDC to the mass of aluminum contained in the aluminum matrix is 3.1%).

The result, of course, is not identical, but acceptable, especially with regard to the nature of the distribution of TDC in the aluminum matrix.

Thus, taking into account the shown cause-and-effect relationships, the invention makes it possible to obtain a workpiece (14) with a structure recommended (in terms of armor resistance) for armor plates, characterized by a predominant concentration of refractory dispersed particles (17) in the surface layer (h) of the aluminum matrix, uniformly over the area of the outer cylindrical surface (15) at any depth of this layer (this is the main technical result of the claimed invention), with additional compaction of the aluminum matrix material over the entire volume of the workpiece (14).

Claims (13)

1. A method for producing a blank of aluminum matrix composite armor plates, which includes preparing a charge in a mixer, obtaining a melt from it in a furnace on a metal base with the introduction of dispersed particles that retain their solid state in the melt, placing the melt with dispersed particles in a container in the shape of the said blank, forcibly moving the dispersed particles in the said melt to a specified distribution over its volume, cooling the melt with dispersed particles to a solid state and, as a finishing operation, removing it from the container with the possibility of subsequent cutting and mechanical processing to form armor plates, characterized in that the charge is prepared on the basis of aluminum in the form of, for example, grits or shavings with the addition of refractory dispersed particles, wetted by the melt and retaining their solid state in the melt, using a mixer, for example an attritor or mill, until a homogeneous mechanical mixture is formed - a premix, prepare by heating in a furnace a melt of the second part of aluminum or an aluminum alloy, for example, a composition of 96% aluminum and 4% silicon, the charge is added to the aluminum or aluminum alloy melt with the simultaneous or subsequent introduction of refractory dispersed particles under the metal mirror and the melt is stirred, for example, with a stirrer, until a uniform distribution of all components is obtained throughout the volume of the melt, the rotation mode of the rotor of a horizontal centrifugal casting machine is switched on and the melt with refractory dispersion particles is loaded from the crucible into the rotor mold by means of a loading container and/or a chute of the said machine, due to the previous operation and, mainly, centrifugal forces in the rotor, a bushing is formed as the mentioned blank with a wall thickness in its middle of at least 7 mm, with a concentration of particles mainly in its surface layer and uniform distribution over the area of the outer cylindrical surface, cool the mold of the centrifugal machine rotor until the formed sleeve is in a solid state, stop the rotation of the rotor of the centrifugal machine, remove the bushing from the mold of the rotor of the centrifugal machine with the possibility of subsequent cutting of the workpiece and mechanical processing until the formation of armor plates. 2. The method according to paragraph 1, characterized in that between the mentioned operations of preparing the charge and adding it to the aluminum-based melt, the charge is pressed with the possibility of compaction. 3. The method according to item 1, characterized in that the refractory dispersed particles are introduced in an amount of 3 to 15 mass%. 4. The method according to any one of paragraphs 1-3, characterized in that oxides, for example aluminum oxide, up to 20 microns in size are used as refractory dispersed particles. 5. The method according to any of paragraphs 1-3, characterized in that carbides, for example silicon carbide, up to 20 µm in size, are used as refractory dispersed particles. 6. The method according to any one of paragraphs 1-3, characterized in that borides, for example titanium or zirconium boride, with a size of up to 20 μm, are used as refractory dispersed particles.