Energy-containing composite connecting piece based on hard alloy and tungsten-containing amorphous alloy and preparation method and application of energy-containing composite connecting piece

Abstract

The invention belongs to the technical field of energetic materials and active fragment materials, and particularly relates to an energetic composite connecting piece based on hard alloy and tungsten-containing amorphous alloy and a preparation method and application of the energetic composite connecting piece. The penetration capability and the damage effect of the energetic material are fully considered, the hard alloy is selected as a penetration part, and the tungsten-containing amorphous alloy composite material is selected as a fragment part. The hard alloy has high hardness and high fracture toughness and can effectively penetrate through the shell; the amorphous alloy composite material has high strength, high energy density and good plastic deformation capacity, can be deflagrated at a high strain rate and release a large amount of energy, and generates a large amount of fragments to damage a target. And the integration of preparation and connection of the hard alloy penetration part and the amorphous alloy composite material fragment part can be realized through spark plasma sintering, so that the technical problems that in the prior art, an inert energetic material is adopted to hit a target but not destroy the target, so that personnel and weaponry are damaged, and the like are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of energetic materials and active fragment materials, and more specifically, relates to an energetic composite connector based on cemented carbide and tungsten-containing amorphous alloy, and a preparation method and application thereof. Background Art

[0002] Small-caliber armor-piercing shells are usually made of high-density tungsten alloys, and have the advantages of high rate of fire, fast response, strong maneuverability, and good armor-piercing ability. They can deal with incoming drones, missiles and other targets with strong air strike capabilities. However, this inert armor-piercing shell has a fatal problem. Since the tungsten core armor-piercing shell is a kinetic shell, it mainly relies on kinetic damage mechanism and mechanical penetration damage. The ordinary tungsten core armor-piercing shell core will "hit but not destroy" the incoming missiles and drones, causing casualties to our own combatants and the destruction of weapons and equipment, which puts them in an unfavorable situation. Therefore, it is necessary to improve the damage efficiency of armor-piercing shells.

[0003] Energetic fragments refer to a new type of damaging material that has certain mechanical properties and good stability under normal conditions, but can trigger violent chemical reactions between material components or between components and the environment under high strain rate impact loads, releasing a large amount of energy. This material is usually composed of two or more non-explosive solids, including thermite, metal / polymer, metastable molecular composite materials, metal-based active materials, etc. However, although these materials have high energy response and destructive power, their density and strength are generally low, which can easily cause the fragments to explode and rupture prematurely during the armor-piercing process, greatly reducing the damage effect on internal targets.

[0004] At the same time, in order to improve the armor-piercing ability of fragments, armor-piercing fragmentation bombs are usually connected together by outer shell wrapping or mechanical locking, which has technical problems such as loose connection, unstable flight and poor destructive effect.

[0005] Patent CN108425057A discloses a fragile armor-piercing tungsten alloy and its preparation method. The tungsten alloy material is composed of W powder, Ni powder, Fe powder, Re powder and Al powder. 2 O 3 Powder mixed and sintered, Al 2 O 3The powder reduces the tensile strength of tungsten alloy and thus increases the fragility of the material. This method can still only produce mechanical penetration damage, and cannot produce damage effects such as shock wave overpressure and thermal damage. Patent CN217058527U discloses a high-penetration multifunctional bullet with a two-body core structure. The front end is a cemented carbide that effectively penetrates hard armor and large-angle oblique armor. The high-density high-entropy alloy at the rear end further increases the armor-piercing kinetic energy, as well as the multifunctional damage effects of fragmentation and burning after armor-piercing. The two are wrapped by an aluminum sleeve. The front and rear ends of this method are still a two-body structure, and the connection is not firm, which will cause the bullet's flight trajectory to be unstable and loss to occur during the kinetic energy transfer process at both ends. At the same time, the density of the cemented carbide at the front end is greater than that of the tungsten-based high-entropy alloy at the rear end, resulting in the forward center of gravity of the projectile, which further leads to unstable flight trajectory and a decrease in the effective striking distance of the bullet, while reducing technical problems such as armor-piercing and damage effects. In summary, the current armor-piercing fragmentation projectile core materials have various problems and the connection method between the warhead and the tail has an adverse effect on the armor-piercing and destructive capabilities of the fragmentation projectile. Therefore, it is of great significance to prepare a new armor-piercing fragmentation projectile core material with high strength, high density and high energy response and a connection method suitable for the warhead and the tail of the armor-piercing fragmentation projectile. Summary of the invention

[0006] In view of the defects of the prior art, the purpose of the present invention is to provide an energetic composite connector based on cemented carbide and tungsten-containing amorphous alloy, and its preparation method and application, aiming to solve the technical problems that the prior art uses inert armor-piercing projectiles to "hit but not destroy" targets such as drones and missiles, resulting in losses of personnel and weapons and equipment, and the traditional connection processes such as shell wrapping or mechanical locking between the core head and the core body are not firm, the flight is unstable and the damage effect is poor.

[0007] To achieve the above-mentioned object, the present invention provides an energetic composite connector based on cemented carbide and tungsten-containing amorphous alloy, comprising a head end penetration part and a tail end fragment part, wherein the head end penetration part is made of cemented carbide, and the tail end fragment part is made of tungsten-containing amorphous alloy; The strength of the cemented carbide used in the head end penetration part is greater than the strength of the tungsten-containing amorphous alloy used in the tail end fragment part, and the hardness of the cemented carbide used in the head end penetration part is greater than the hardness of the tungsten-containing amorphous alloy used in the tail end fragment part; The head end penetration part and the tail end fragment part are connected in an integrated manner through spark plasma sintering.

[0008] Preferably, the length ratio of the head end penetration portion to the tail end fragment portion is 0.5-1.5.

[0009] Preferably, the head end penetration part includes two areas, a main penetration part at the head end and a secondary penetration part at the sub-head end, and the secondary penetration part at the sub-head end is arranged to be a gradient cemented carbide material, and the density of the gradient cemented carbide material increases gradually from the head to the tail, so that the overall center of gravity of the energetic composite connector moves backward and close to the centroid of the energetic composite connector, thereby ensuring that the energetic composite connector flies stably.

[0010] Further preferably, the gradient is a structural gradient and / or a composition gradient; by regulating the content of the raw material components used in the preparation of the gradient cemented carbide or regulating the temperature field distribution during the sintering process when preparing the gradient cemented carbide, a sub-head end and sub-penetration part of the cemented carbide material with a gradient increase in density in the direction from the head to the tail is obtained.

[0011] According to another aspect of the present invention, there is provided a method for preparing the energetic composite connector, comprising the following steps: (1) roughening the surface of the cemented carbide block to be connected used in the head end penetration portion to obtain a roughened surface of the cemented carbide block to be connected in the head end penetration portion; (2) uniformly mixing the amorphous alloy powder and the tungsten reinforcement phase powder used in the tail fragment part to obtain the tungsten / amorphous alloy composite powder used in the tail fragment part; (3) directly performing spark plasma sintering to connect the tungsten / amorphous alloy composite powder of step (2) and the surface of the cemented carbide block to be connected after the roughening treatment of step (1) to obtain the energetic composite connecting part; or, First, the tungsten / amorphous alloy composite powder of step (2) is prepared into an amorphous alloy composite material block by spark plasma sintering, and then the surface to be connected is roughened to obtain the roughened surface of the amorphous alloy composite material block to be connected used by the tail end fragment part; then the roughened surface of the amorphous alloy composite material block to be connected used by the tail end fragment part is welded together with the roughened surface of the cemented carbide block to be connected used by the head end penetration part in step (1) to obtain the energetic composite connector.

[0012] According to another aspect of the present invention, there is provided an armor-piercing fragmentation projectile, the core material of which comprises the energetic composite connector as described above.

[0013] In general, the above technical solution conceived by the present invention has the following technical advantages compared with the prior art: (1) The present invention provides an energetic composite connector based on cemented carbide and tungsten-containing amorphous alloy, which fully takes into account the penetration ability and damage effect of energetic materials. The present invention selects cemented carbide as the penetration part and tungsten-containing amorphous alloy composite material as the fragment part. Cemented carbide has high hardness and high fracture toughness, and can effectively penetrate the shell; the amorphous alloy composite material has high strength, high energy density and good plastic deformation ability, and can explode and release a large amount of energy at a high strain rate, generating a large number of fragments to cause damage to the target. Discharge plasma sintering can realize the integration of the preparation and connection of the cemented carbide penetration part and the amorphous alloy composite material fragment part, thereby solving the technical problems of the prior art that the inert energetic material is used to "hit but not destroy" the target, resulting in losses of personnel and weapons and equipment.

[0014] (2) The present invention provides a method for preparing an energetic composite connector based on cemented carbide and tungsten-containing amorphous alloy, wherein the tungsten / amorphous alloy composite powder used in the tail end fragment part and the surface to be connected of the cemented carbide block used in the head end penetration part after roughening are directly sintered and connected by spark plasma sintering to obtain the energetic composite connector of the present invention; or, the tungsten / amorphous alloy composite powder used in the tail end fragment part is first prepared into an amorphous alloy composite material block by spark plasma sintering, and then the surface to be connected of the amorphous alloy composite material block used in the tail end fragment part after roughening is welded to the surface to be connected of the cemented carbide block used in the head end penetration part after roughening, to obtain the energetic composite connector that can be used for armor-piercing fragmentation projectiles. Common preparation processes for energetic materials of armor-piercing fragmentation projectiles include compression molding and sintering, explosive molding, etc. However, these methods have defects in different aspects. For example, the density of the material obtained by compression molding and sintering is uneven, and the explosive molding method has problems such as explosion safety, noise pollution, and difficulty in controlling product manufacturing tolerances. These have a certain degree of influence on the strength, density, and other properties of energetic fragments. The present invention first selects a suitable amorphous alloy component for the tail (i.e., the tail end fragment part) and a second phase reinforcement phase component, and then mixes them evenly, and prepares an amorphous alloy composite material block and a cemented carbide block through a spark plasma sintering process, or directly sintering an amorphous alloy composite material powder and a cemented carbide block through a spark plasma sintering process. Spark plasma sintering is a rapid sintering technology that achieves densification by passing a pulse current through a powder or block material and assisting with pressure. It has the characteristics of fast sintering speed, low sintering temperature, and low required pressure, and can obtain a fragment material with high density and excellent mechanical properties.

[0015] (3) The present invention provides an energetic composite connector that fully takes into account the penetration performance and damage performance of fragments, and selects amorphous alloy composite materials as fragment materials. Compared with crystalline materials, amorphous materials do not have defects such as dislocations and grain boundaries, so amorphous materials generally have excellent mechanical properties such as ultra-high mechanical strength and high elastic modulus. At the same time, considering the lack of plasticity of amorphous alloys, adding tungsten particles to amorphous alloys to prepare amorphous alloy composite materials can effectively improve the plasticity of amorphous alloys and enhance the penetration ability of fragments. At the same time, the introduction of tungsten particle reinforcement phase increases the number of interfaces inside the amorphous alloy composite material, so that the material can produce more fragments along the interface when it explodes.

[0016] (4) When the energetic composite connector provided by the present invention is used as the core material of an armor-piercing fragmentation projectile, the amorphous alloy component in the material of the tail fragment part can be a zirconium-based, zirconium-titanium-based, zirconium-niobium-based amorphous alloy with high storage energy, and the storage energy in the glass state can reach 40% to 50% of the melting heat. Under high stress, it breaks to form a high-temperature fragment cloud, and the contact area with oxygen increases, which deflagrates and releases a large amount of energy. Although there is only a small amount of gas or even no gas in the reaction product, it still has the potential to achieve "gasless explosion", and can produce combined damage effects such as shock wave overpressure and thermal damage, greatly improving the damage power of armor-piercing fragmentation projectiles.

[0017] (5) The warhead and fragments in the core of traditional armor-piercing fragmentation projectiles are usually connected by shell wrapping or mechanical locking, which will cause technical problems such as loose connection, unstable flight and poor damage effect. SPS welding, which is developed based on spark plasma sintering technology, is a low-temperature, small deformation, fast vacuum welding method that has developed rapidly in recent years. It adds or does not add an intermediate layer under power heating and pressure to achieve the connection of dissimilar materials. Compared with traditional diffusion welding processes, SPS diffusion welding often has outstanding advantages such as low connection temperature, short welding time, interface mass transfer, fast bridging, and high welding accuracy. The present invention can directly connect the amorphous alloy composite material tail with the cemented carbide warhead through SPS welding technology to obtain a connection joint with excellent mechanical properties. At the same time, the flight trajectory of the integrated core is more stable and the penetration capability is stronger than that of the split core.

[0018] (6) The energetic composite connector provided by the present invention can be used as the core material of armor-piercing fragmentation projectiles. The amorphous alloy composite powder and the cemented carbide block are prepared into armor-piercing fragmentation projectile cores by spark plasma sintering, which can realize the integration of preparation and connection, simplify the production process, and reduce the production cost. At the same time, this method has great controllability and can flexibly change the material type, size, shape and gradient structure to produce different strike effects and deal with different strike targets.

[0019] (7) When an object is made of the same homogeneous material, the center of gravity and the center of shape of the object coincide, and the object can maintain a balanced state during flight. However, when the energetic composite connector of the present invention is used as the core material of an armor-piercing fragmentation projectile, the density of the hard alloy warhead part (>15 g / cm 3 ) is larger than the amorphous alloy composite material tail (7~12g / cm 3 ), the center of gravity of the projectile moves forward, and the bullet will fall during flight, causing the effective striking distance of the bullet to decrease, while reducing the armor-piercing and damaging effects. In the preferred embodiment of the present invention, the bullet is divided into two regions of the main armor-piercing part at the head end and the secondary armor-piercing part at the secondary head end by cemented carbide. The main armor-piercing part of the cemented carbide bullet is uniform and has a large density, ensuring the armor-piercing ability of the bullet; at the same time, by changing the raw material composition of the secondary armor-piercing part of the cemented carbide bullet during preparation, such as the content of the matrix material and / or the bonding phase or the temperature field distribution during the sintering process, the density of the secondary armor-piercing part of the prepared cemented carbide bullet is increased along the head to the tail, so that the center of gravity of the core material as a whole moves backward and approaches the centroid. Under the premise of taking into account the penetration and damaging capabilities of the armor-piercing fragmentation projectile, the method of setting the density gradient takes into account the problems of unstable flight trajectory and reduced effective striking distance of the bullet caused by uneven mass distribution of the two-body projectile, and adjusts the center of gravity to be close to or coincide with the centroid of the projectile, thereby greatly improving the stability of the projectile during flight. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The figure is a schematic diagram of the structure and materials of an armor-piercing projectile core according to an embodiment of the present invention.

[0021] Figure 2 is a schematic diagram of the flight trajectory of the armor-piercing fragmentation projectile according to the present invention, Figure 2 1 represents the flight trajectory when the center of gravity is balanced, and 2 represents the flight trajectory when the center of gravity is forward.

[0022] Figure 3 is a schematic structural diagram of a gradient cemented carbide according to an embodiment of the present invention, Figure 3 1 is the main armor-piercing part of the carbide head end, and 2 is the secondary armor-piercing part of the carbide secondary head end.

[0023] Figure 4 The present invention is a flow chart of the preparation of the armor-piercing fragmentation projectile core material and the connection method thereof.

[0024] Figure 5 This is a schematic diagram of the preparation and connection of the armor-piercing projectile core and the spark plasma sintering mold of Example 1 of the present invention. In which: 1-upper pressure head, 2-amorphous alloy / tungsten composite powder, 3-lower pressure head, 4-upper electrode, 5-die, 6-lower electrode, 7-amorphous alloy composite material, 8-hard alloy material.

[0025] Figure 6 The figure is a schematic diagram of the preparation and connection of the armor-piercing projectile core and the spark plasma sintering mold of Example 2 of the present invention, wherein: 2-amorphous alloy / tungsten composite powder, 8-hard alloy material.

[0026] Figure 7 It is a schematic diagram of the composition gradient setting of the cemented carbide in Example 3 of the present invention.

[0027] Figure 8 1 is a schematic diagram of the center of gravity and main dimensions of each part in a cross-sectional view of an armor-piercing projectile core of Example 3 of the present invention, in which c1, c2, and c3 are respectively the centers of gravity of the main armor-piercing part of the cemented carbide head end, the secondary armor-piercing part of the cemented carbide secondary head end, and the tail of the amorphous alloy composite material fragment, c1 , X c2 , X c3 is the horizontal distance between c1, c2, c3 and the warhead tip, d 1 d 2 d 3 They are the total length of the main armor-piercing part of the carbide head end and the secondary armor-piercing part of the carbide secondary head end, the length of the secondary armor-piercing part of the carbide secondary head end, and the length of the tail of the amorphous alloy composite material fragment. , They are respectively the diameter of the cross section of the main armor-piercing part of the carbide head end, the diameter of the secondary armor-piercing part of the carbide secondary head end or the diameter of the cross section of the amorphous alloy composite material fragment tail.

[0028] Fig. 9 Schematic diagram of the gradient structure of the secondary armor-piercing part of the cemented carbide in Example 3 of the present invention. represents density, x 1 、x 2 …x n represents horizontal length and h represents height). DETAILED DESCRIPTION

[0029] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme in the embodiment of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention.

[0030] The embodiments of the present invention are implemented on the premise of the technical solution of the present invention, and detailed implementation methods and processes are given, but the protection scope of the present invention is not limited to the following embodiments. The process parameters of the following embodiments that do not specify specific conditions are usually based on conventional conditions.

[0031] The endpoints and any values ​​of the ranges disclosed in the present invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in the present invention.

[0032] In the present invention, unless otherwise specified and / or described, all numerical values ​​involving the amounts of components are "parts by weight" from beginning to end. The process parameters in the following examples without specifying specific conditions are usually based on conventional conditions.

[0033] The present invention provides an energetic composite connector based on cemented carbide and tungsten-containing amorphous alloy, comprising a head end penetration part and a tail end fragment part, wherein the material of the head end penetration part is cemented carbide, and the material of the tail end fragment part is tungsten-containing amorphous alloy; wherein the strength of the cemented carbide used in the head end penetration part is greater than the strength of the tungsten-containing amorphous alloy used in the tail end fragment part, and the hardness of the cemented carbide used in the head end penetration part is greater than the hardness of the tungsten-containing amorphous alloy used in the tail end fragment part; the head end penetration part and the tail end fragment part are connected in an integrated manner by spark plasma sintering.

[0034] In some embodiments, the energetic composite connector of the present invention is used as a core material of an armor-piercing fragmentation projectile, such as Figure 1 As shown, the fragment core material includes a warhead and a tail, the warhead is the penetrating part at the head end, and the tail is the fragment part at the tail end, the warhead is a cemented carbide, and the tail is a tungsten-containing amorphous alloy; wherein the strength of the cemented carbide used for the warhead is greater than the strength of the tungsten-containing amorphous alloy used for the tail, and the hardness of the cemented carbide used for the warhead is greater than the hardness of the tungsten-containing amorphous alloy used for the tail.

[0035] In some embodiments, the head end penetrating portion, i.e. Figure 1 The Vickers hardness of the cemented carbide used in the bullet head is greater than or equal to 15 GPa and the density is greater than> 15 g / cm 3 , flexural strength greater than or equal to 1500 MPa, fracture toughness greater than or equal to 10MPa•m 1 / 2; The selection criteria for the composition of the hard alloy used in the bullet head are: the composition of the hard alloy is tungsten-cobalt, tungsten-nickel, tungsten-nickel-cobalt hard alloy. Including but not limited to WC-Co, WC-Ti-Co, WC-Ni, WC-Ni-Co; The selection criteria for the composition of the tungsten-containing amorphous alloy used in the tail fragment part, that is, the tail of the bullet, are: the composition of the amorphous alloy matrix is ​​zirconium-based, zirconium-titanium-based, zirconium-niobium-based amorphous alloy, including but not limited to ZrCuAl, ZrCuNiAl, ZrCuNiAlTi, ZrTiCuNiBe. Its energy density per unit mass is greater than or equal to 5 KJ•g -1 , density is 7~12g / cm 3 , and the critical forming size of the amorphous alloy component is greater than or equal to 0.1 mm, and the temperature upper and lower limit difference of the supercooled liquid phase region is greater than 40 K; the reinforcing phase component in the amorphous alloy is tungsten particles.

[0036] In some embodiments, the length ratio of the head end penetration portion to the tail end fragmentation portion is 0.5-1.5, preferably 0.8-1.2. Controlling within this range ensures the excellent armor-piercing fragmentation capability of the connector. The length of the head end penetration portion and the tail end fragmentation portion mentioned here refers to the length along the armor-piercing flight direction of the connector when it is used as the core material of the armor-piercing fragmentation projectile. The size of the core material perpendicular to its armor-piercing flight direction is selected according to needs.

[0037] When an object is made of the same homogeneous material, the center of gravity and the center of shape of the object coincide, and the object can maintain a balanced state during flight. However, when the energetic composite connector of the present invention is used as the core material of an armor-piercing fragmentation projectile, the density of the hard alloy bullet part, i.e., the penetrating part at the head end, in the armor-piercing fragmentation projectile (>15 g / cm 3 ) is greater than the density of the tail of the amorphous alloy composite material (7~12 g / cm 3 ), the center of gravity of the projectile moves forward, and the bullet will fall severely during flight, such as Figure 2 As shown, the effective striking distance of the bullet is reduced, while the armor-piercing and destructive effects are reduced. Figure 2 1 represents the flight trajectory when the center of gravity is balanced, and 2 represents the flight trajectory when the center of gravity is forward. Figure 3 As shown, the warhead is divided into two regions of a head end main armor-piercing part 1 (i.e., the main penetration part at the most head end) and a sub-head end secondary armor-piercing part 2 (i.e., the sub-head end secondary penetration part), and the sub-head end secondary armor-piercing part is set to be a gradient cemented carbide material. The gradient cemented carbide material makes the density of the cemented carbide of the sub-head end secondary armor-piercing part increase gradually from the head to the tail, so that the overall center of gravity of the core material moves backward and close to the centroid of the core material, thereby ensuring that the core material flies smoothly.

[0038] Specifically, the gradient is a structural gradient and / or a composition gradient; by regulating the raw material components used in the preparation of the cemented carbide, such as the content of the carbide matrix and / or the binder, or by designing the temperature field distribution during the sintering process when preparing the cemented carbide, a cemented carbide material of the sub-head end and sub-armor-piercing part with a density gradiently increasing in the direction from the head to the tail is obtained.

[0039] For example, in some embodiments, the cemented carbide is a powder metallurgy product made of carbide (WC, TiC) micron-sized powder of high-hardness refractory metal as the main component, cobalt (Co), nickel (Ni) or molybdenum (Mo) as a binder, and sintered in a vacuum furnace or a hydrogen reduction furnace; by adjusting the content of carbide and / or binder, a density of 5 to 16 g / cm in the direction from head to tail is prepared. 3 The secondary head end and the secondary armor-piercing part of the hard alloy have a gradient increase within the range, so that the center of gravity moves backward and closer to the centroid of the object.

[0040] In some other embodiments, the gradient cemented carbide may be a structural gradient. By designing and regulating the temperature field distribution during the sintering process of the cemented carbide, the density in the direction from the head to the tail is 5-16 g / cm 3 The secondary head end and the secondary armor-piercing part of the hard alloy have a gradient increase within the range, so that the center of gravity moves backward and closer to the centroid of the object.

[0041] The present invention also provides a method for preparing the energetic composite connector, comprising the following steps: (1) roughening the surface of the cemented carbide block to be connected used in the head end penetration portion to obtain a roughened surface of the cemented carbide block to be connected in the head end penetration portion; (2) uniformly mixing the amorphous alloy powder and the tungsten reinforcement phase powder used in the tail fragment part to obtain the tungsten / amorphous alloy composite powder used in the tail fragment part; (3) directly performing spark plasma sintering to connect the tungsten / amorphous alloy composite powder of step (2) and the surface of the cemented carbide block to be connected after the roughening treatment of step (1) to obtain the energetic composite connecting part; or, First, the tungsten / amorphous alloy composite powder of step (2) is prepared into an amorphous alloy composite material block by spark plasma sintering, and then the surface to be connected is roughened to obtain the roughened surface of the amorphous alloy composite material block to be connected used by the tail end fragment part; then the roughened surface of the amorphous alloy composite material block to be connected used by the tail end fragment part is welded together with the roughened surface of the cemented carbide block to be connected used by the head end penetration part in step (1) to obtain the energetic composite connector.

[0042] In some embodiments, the energetic composite connector is used as a core material for an armor-piercing fragmentation projectile, such as Figure 4 As shown, the preparation method comprises the following steps: (1) roughening the surface of the armor-piercing fragmentation projectile warhead cemented carbide block to be connected, thereby obtaining a roughened surface of the warhead cemented carbide block to be connected; (2) uniformly mixing the amorphous alloy powder for the tail of the armor-piercing fragmentation projectile and the tungsten reinforcement phase powder to obtain a tungsten / amorphous alloy composite powder for the tail of the projectile; (3) directly performing spark plasma sintering to connect the tungsten / amorphous alloy composite powder for the tail of the projectile in step (2) and the roughened hard alloy block for the projectile in step (1) to obtain the core material of the armor-piercing fragmentation projectile; or, First, the tungsten / amorphous alloy composite powder for the tail of the projectile in step (2) is prepared into an amorphous alloy composite material block by spark plasma sintering, and then the surface to be connected is roughened to obtain the roughened surface of the amorphous alloy composite material block for the tail of the projectile to be connected; then the roughened surface of the amorphous alloy composite material block for the tail of the projectile to be connected is welded to the roughened surface of the hard alloy block for the warhead to be connected in step (1) to obtain the armor-piercing fragmentation projectile core material.

[0043] In some embodiments, the roughening treatment in step (1) and step (3) is independently one or more of sandpaper polishing and laser roughening; the roughness of the surface of the hard alloy block for the bullet head to be connected after the roughening treatment is less than 2.5 μm; the roughness of the surface of the amorphous alloy composite material block for the bullet tail to be connected after the roughening treatment is less than 2.5 μm.

[0044] In some embodiments, the roughening treatment in step (1) and step (3) is first sandpaper polishing and then laser roughening, and the hole spacing of the laser roughening treatment is 50~150μm, the laser pulse energy is 1.0 mJ~2.0 mJ, the pulse width is 150~300 ns, and the pulse frequency is 10~100 kHz.

[0045] In some embodiments, the volume fraction of the tungsten reinforcement phase powder in the tungsten / amorphous alloy composite powder is within a range of 20% to 60%, and the shape of the tungsten reinforcement phase powder is spherical, ellipsoidal, flake, or the like.

[0046] In some embodiments, the amorphous alloy powder and the tungsten-reinforced phase powder are independently prepared by atomization, water atomization, mechanical ball milling, plasma ball milling, or plasma rotating electrode method.

[0047] In some embodiments, the powdered amorphous alloy powder has a particle size in the range of 1 μm to 50 μm, and the powder particle size of the tungsten reinforcement phase is in the range of 1 μm to 100 μm.

[0048] In some embodiments, step (2) uses a ball milling process to evenly mix the amorphous alloy powder and the tungsten reinforcement phase powder; the process parameters of the ball milling process are: the grinding ball material is cemented carbide, stainless steel or agate, the rotation speed is 100~800r / min, the ball-to-material ratio is 30:1~3:1, and the ball milling time is 10 min~24 h.

[0049] In some embodiments, step (3) directly performs spark plasma sintering to connect the tungsten / amorphous alloy composite powder for the tail of the projectile in step (2) and the roughened hard alloy block for the projectile in step (1) by spark plasma sintering, the sintering temperature is set in the supercooled liquid phase region of the amorphous alloy, the sintering pressure is 50~150 MPa, the sintering time is 5~30 min, and the heating and cooling rate is 10~100 K / min.

[0050] In some embodiments, step (3) prepares the tungsten / amorphous alloy composite powder for the tail of step (2) into an amorphous alloy composite material block by spark plasma sintering, the sintering temperature is set in the supercooled liquid phase region of the amorphous alloy, the sintering pressure is 100~600 MPa, the sintering time is 5~30 min, and the heating and cooling rate is 20~200 K / min.

[0051] In some embodiments, in step (3), the roughened amorphous alloy composite material block for the tail of the bullet and the roughened hard alloy block for the bullet head of step (1) are welded together, and the welding temperature is set to be 10~100 K below the glass transition end temperature Tx of the amorphous alloy, the welding pressure is 10~150 MPa, the welding time is 1~10 min, and the heating and cooling rate is 10~100 K / min.

[0052] In a preferred embodiment, the step (1) comprises a main armor-piercing portion at the head end and a secondary armor-piercing portion at the sub-head end, and the secondary armor-piercing portion at the sub-head end is made of a gradient cemented carbide whose density increases gradually from the head end to the tail end; the preparation method of the gradient cemented carbide comprises the following steps: obtaining a cemented carbide material of the secondary armor-piercing portion at the sub-head end whose density increases gradually from the head end to the tail end by regulating the content of the raw material components used in the preparation of the gradient cemented carbide or regulating the temperature field distribution during the sintering process when preparing the gradient cemented carbide.

[0053] The present invention belongs to the technical field of energetic materials and active fragment materials, and more specifically, relates to an energetic composite connector based on cemented carbide and tungsten-containing amorphous alloy, a preparation method and application thereof, wherein the connector can be used as a core material of an armor-piercing fragmentation projectile, and fully takes into account the penetration capability and damage effect of the armor-piercing fragmentation projectile, and selects cemented carbide as the armor-piercing warhead and tungsten-containing amorphous alloy composite material as the fragmentation tail. The amorphous alloy composite material has high strength, high energy density and good plastic deformation ability, and can deflagrate and release a large amount of energy at a high strain rate, generating a large number of fragments to cause damage to targets inside the armor. The integrated preparation and connection of the cemented carbide warhead and the amorphous alloy composite tail can be achieved through spark plasma sintering, thereby solving the technical problems that the existing technology uses inert armor-piercing projectiles to "hit but not destroy" the target, resulting in losses of personnel and weapons and equipment, and the connection process between the traditional core head and the core body using shell wrapping or mechanical locking is not firm, the flight is unstable and the damage effect is poor.

[0054] The following are examples: Example 1 The energetic composite connector based on cemented carbide and tungsten-containing amorphous alloy provided in this embodiment is used as the core material of armor-piercing fragmentation projectile. The head end penetration part, i.e., the warhead, is made of cemented carbide with good mechanical properties (Hv>22GPa, bending strength>2200MPa, density 15.7 g / cm 3 , fracture toughness>12 MPa•m 1 / 2 ), the tail end fragment part, that is, the tail of the projectile is made of amorphous alloy, and its matrix component is selected from Zr with high energy density and good mechanical properties. 55 Cu 30 Al 5 Ni 10 (Tg=411℃, Tx=484℃, density is 7 g / cm 3 , the energy density per unit mass is 10.981 KJ•g -1 ,σ=1900MPa), and the critical forming size of the amorphous alloy is not less than 0.1 mm. WC-3%Co cemented carbide is used as the material of armor-piercing warhead, and Zr 55 Cu 30 Al 5 Ni 10 Amorphous alloy and W particles are composited as fragment tail materials. Zr 55 Cu 30 Al 5 Ni 10 / W amorphous alloy composite block, and then WC-Co and Zr are diffused by SPS 55 Cu 30 Al 5 Ni10 / W are welded together. The specific preparation method is as follows: According to the nominal composition, high-purity metal raw materials were weighed and arc-melted six times in an argon atmosphere using a Ti getter to obtain Zr. 55 Cu 30 Al 5 Ni 10 The master alloy ingots of Zn and W were prepared by high nitrogen atomization method to prepare amorphous alloy and tungsten powders. The high-purity nitrogen atomization pressure was 20 MPa, the guide hole diameter was 2 mm, and the zirconium-based amorphous alloy powders with a particle size of 1 μm~50 μm and tungsten powders with a particle size of 1 μm~100 μm were screened out.

[0055] The zirconium-based amorphous alloy powder and tungsten powder were evenly mixed by ball milling to obtain an amorphous alloy composite powder, in which the volume fraction of tungsten reinforcement phase powder was 40%. The grinding ball was made of cemented carbide, the rotation speed was 600 r / min, the ball-to-material ratio was 10:1, and the ball milling time was 7h. Figure 5 In the schematic diagram of the spark plasma sintering mold shown in the figure (1-upper pressure head, 2-amorphous alloy composite powder, 3-lower pressure head, 4-upper electrode, 5-die, 6-lower electrode, 7-amorphous alloy composite material, 8-hard alloy material), Zr was prepared by spark plasma sintering technology. 55 Cu 30 Al 5 Ni 10 / W composite material block, the process parameters adopted by spark plasma sintering are: sintering temperature of 723 K, sintering pressure of 300 MPa, sintering time of 5 min, and heating and cooling rate of 50 K / min.

[0056] WC-3%Co cemented carbide is processed into Figure 1 The shape shown in the cemented carbide bullet is then polished with sandpaper of different meshes on the surfaces to be connected between the cemented carbide and the amorphous alloy composite material blocks. The polishing order is 400 mesh, 800 mesh, 1200 mesh and 2000 mesh, and each polishing is performed until there are no obvious scratches on the surface. The polished surface is then laser roughened with a hole spacing of 100 μm, a laser pulse energy of 1.8 mJ, a pulse width of 240 ns, and a pulse frequency of 30 kHz. WC-3%Co cemented carbide (length 19 mm) and Zr 55 Cu 30 Al 5 Ni 10 / W composite material block (length 20 mm), the process parameters adopted by spark plasma sintering welding are: welding temperature 623 K, welding pressure 100 MPa, welding time 2 min, and heating and cooling rate 50 K / min.

[0057] Example 2 The energetic composite connector based on cemented carbide and tungsten-containing amorphous alloy provided in this embodiment is used as the core material of armor-piercing fragmentation projectile. The head end penetration part, i.e., the warhead, is made of cemented carbide with good mechanical properties (Hv>15GPa, bending strength>2100MPa, density 15.2g / cm 3 , fracture toughness>12 MPa•m1 / 2), the tail fragment part, that is, the tail of the projectile, is made of amorphous alloy, and its matrix component is Zr with high energy density and good mechanical properties. 55 Cu 30 Al 5 Ni 10 (Tg=411℃, Tx=484℃, density is 7g / cm 3 , the energy density per unit mass is 10.981 KJ•g -1 ,σ=1900 MPa), and the critical forming size of the amorphous alloy is not less than 0.1 mm. WC-10%Ni cemented carbide is used as the material of armor-piercing warhead, and Zr 55 Cu 30 Al 5 Ni 10 Amorphous alloy and W particles are composited as fragment tail materials. Powdered Zr 55 Cu 30 Al 5 Ni 10 / W is welded together with bulk WC-10%Ni. The specific preparation method is as follows: According to the nominal composition, high-purity metal raw materials were weighed and arc-melted six times in an argon atmosphere using a Ti getter to obtain Zr. 55 Cu 30 Al 5 Ni 10 The master alloy ingots of Zn and W were prepared by high nitrogen atomization method to prepare amorphous alloy and tungsten powders. The high-purity nitrogen atomization pressure was 20 MPa, the guide hole diameter was 2 mm, and the zirconium-based amorphous alloy powders with a particle size of 1 μm~50 μm and tungsten powders with a particle size of 1 μm~100 μm were screened out.

[0058] The zirconium-based amorphous alloy powder and tungsten powder were evenly mixed by ball milling to obtain an amorphous alloy composite material powder, in which the volume fraction of tungsten reinforcement phase powder was 40%. The grinding ball was made of cemented carbide, the rotation speed was 600r / min, the ball-to-material ratio was 10:1, and the ball milling time was 7h. The WC-10%Ni cemented carbide was processed into Figure 1 The shape of the carbide bullet is shown in the figure. Then, the surface of the carbide to be connected is first polished with sandpaper of different meshes. The polishing order is 400 mesh, 800 mesh, 1200 mesh and 2000 mesh. Each polishing is performed until there are no obvious scratches on the surface. Then, the polished surface is treated with laser surface roughening. The hole spacing is 100μm, the laser pulse energy is 1.8mJ, the pulse width is 240 ns, and the pulse frequency is 30 kHz. Figure 6 In the schematic diagram of the spark plasma sintering mold shown in the figure (2-amorphous alloy composite powder, 8-hard alloy material), WC-10%Ni hard alloy and Zr are prepared by spark plasma sintering welding technology. 55 Cu 30 Al 5 Ni 10 / W amorphous alloy composite powder welding parts, the process parameters adopted by spark plasma sintering are: sintering temperature is 723 K, sintering pressure is 100 MPa, sintering time is 10 min, and heating and cooling rate is 50 K / min. After sintering, the length of the hard alloy in the core material is 19 mm, and the length of the amorphous alloy is 20 mm.

[0059] Example 3 The energetic composite connector based on cemented carbide and tungsten-containing amorphous alloy provided in this embodiment is used as the core material of armor-piercing fragmentation projectile. WC-x%TiC-10%Ni (x=0, 30, 60, 90) cemented carbide is selected as the head end penetration part, i.e., the armor-piercing projectile material, wherein the density of WC is 15.9 g / cm 3 The density of TiC is 4.9 g / cm 3 , the density of Ni is 8.9 g / cm 3 . Zr 55 Cu 30 Al 5 Ni 10 Amorphous alloy and W particles are composited as the tail fragment part, i.e. the tail material of the fragment. The powdered Zr 55 Cu 30 Al 5 Ni 10 / W is welded together with bulk WC-x%TiC-10%Ni (x=0,30,60,90). The specific preparation method is as follows: According to the nominal composition, high-purity metal raw materials were weighed and arc-melted six times in an argon atmosphere using a Ti getter to obtain Zr. 55 Cu 30 Al 5 Ni 10 The master alloy ingot of zirconium and W was prepared by high nitrogen atomization method to prepare amorphous alloy and tungsten powders. The high-purity nitrogen atomization pressure was 20 MPa, the guide hole diameter was 2 mm, and the zirconium-based amorphous alloy powder with a particle size of 1 μm~50 μm and the tungsten powder with a particle size of 1 μm~100 μm were screened out. The zirconium-based amorphous alloy powder and tungsten powder were evenly mixed by ball milling to obtain an amorphous alloy composite material powder, in which the volume fraction of tungsten reinforcement phase powder accounted for 40%. The grinding ball was made of cemented carbide, the rotation speed was 600 r / min, the ball-to-material ratio was 10:1, and the ball milling time was 7 h.

[0060] Put cemented carbide powder with different carbide contents into Figure 5 The sintering was carried out in the mold shown in the figure, with a sintering temperature of 1250°C, a holding time of 1h, a heating rate of 100°C / min, and a sintering pressure of 50MPa. Figure 3 The middle number 1) is 90% WC-0% TiC-10% Ni, with a height of 7mm and a secondary armor-piercing part ( Figure 3 The middle bid number 2) includes 4 layers, each layer is 3mm high, the first layer is 0%WC-90%TiC-10%Ni, the TiC content of each layer decreases by 30% layer by layer, and the WC content increases by 30% layer by layer. The specific distribution is shown in Figure 7 and Table 1: Table 1

[0061] The sintered WC-Ni gradient cemented carbide is processed into Figure 3 The shape is shown in the figure. Then, the surface of the cemented carbide to be connected is polished with sandpaper of different meshes in sequence. The polishing order is 400 mesh, 800 mesh, 1200 mesh and 2000 mesh. Each polishing is performed until there are no obvious scratches on the surface. Then, the polished surface is subjected to laser surface roughening treatment. The hole spacing is 100 μm, the laser pulse energy is 1.8 mJ, the pulse width is 240 ns, and the pulse frequency is 30 kHz. Figure 6 In the schematic diagram of the spark plasma sintering mold shown in the figure (2-amorphous alloy composite powder, 8-hard alloy material), WC-TiC-Ni gradient hard alloy and Zr are prepared by spark plasma sintering welding technology. 55 Cu 30 Al 5 Ni 10 / W amorphous alloy composite powder welding parts, the process parameters adopted by spark plasma sintering are: sintering temperature of 723 K, sintering pressure of 100 MPa, sintering time of 10 min, and heating and cooling rate of 50 K / min.

[0062] The following is a calculation to compare the effect of whether or not to set a gradient carbide bullet on the center of gravity of the overall core material.

[0063] The center of gravity of the armor-piercing fragmentation projectile can be calculated in the following way. Figure 8 As shown in the figure, for the center of gravity position c of the armor-piercing fragmentation projectile, considering that the projectile body is axisymmetric and its center of gravity is on the axis, we only need to consider the horizontal coordinate position x of the center of gravity on the axis. c The center of gravity referred to below is the horizontal axis position of the center of gravity. The armor-piercing fragmentation projectile can be divided into three parts. The first part is the main armor-piercing part 1 of the armor-piercing warhead, the second part is the secondary armor-piercing part 2 of the armor-piercing warhead, and the third part is the tail part 3 of the fragmentation projectile, and the corresponding centers of gravity are c1, c2, and c3 respectively.

[0064] Assume that the horizontal coordinate position of the center of gravity on the axis is , and According to the center of gravity formula, we can get:

[0065]

[0066]

[0067] set up , , For the quality of each part, is the density of cemented carbide, is the density of the amorphous alloy composite material, then the mass of each part is:

[0068]

[0069]

[0070] For a system with objects of different masses, it is necessary to take the coordinates of the center of gravity of each figure to calculate the total center of gravity coordinates, so the center of gravity position of the entire armor-piercing fragmentation projectile is:

[0071] For a system of objects with a density gradient, the barycentric coordinates of each part are also taken to calculate the total barycentric coordinates, such as Fig. 9 As shown, the center of gravity of Part 2 is:

[0072]

[0073] Then the center of gravity of the object after adding the gradient is:

[0074] Assuming that the density of the armor-piercing fragmentation projectile is uniform, the above calculation formula shows that the centroid position of the armor-piercing fragmentation projectile body is located 19.3 mm to the right of the front end of the hard alloy armor-piercing projectile. 1 =19 mm, d 2 =12 mm, d 3 =20 mm, =15.2 g / cm 3 , =10 g / cm 3 , =6 mm, =8.6 mm. Substituting the parameters into the above formula, we can get that the center of gravity of the armor-piercing fragmentation projectile without gradient carbide warhead is =18.2 mm, the center of gravity of the armor-piercing fragmentation projectile after adopting the gradient carbide warhead is located at =19.1 mm.

[0075] From the above calculations, it can be seen that when the secondary armor-piercing part of the bullet is made of gradient cemented carbide, the center of gravity of the entire core material can be moved backward to 19.1 mm, which is only 0.2 mm away from the centroid. The center of gravity and the centroid are almost coincident, so the core material is expected to be more stable during flight.

[0076] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An energetic composite connector based on cemented carbide and tungsten-containing amorphous alloy, characterized in that: It includes a head end penetration part and a tail end fragment part, wherein the head end penetration part is made of hard alloy, and the tail end fragment part is made of tungsten-containing amorphous alloy; The strength of the cemented carbide used in the head end penetration part is greater than the strength of the tungsten-containing amorphous alloy used in the tail end fragment part, and the hardness of the cemented carbide used in the head end penetration part is greater than the hardness of the tungsten-containing amorphous alloy used in the tail end fragment part; The head end penetration part and the tail end fragment part are connected in an integrated manner through spark plasma sintering.

2. The energetic composite connector according to claim 1, characterized in that: The hard alloy used in the head end penetration part has a Vickers hardness greater than or equal to 15 GPa, a bending strength greater than or equal to 1500 MPa, and a fracture toughness greater than or equal to 10 MPa•m 1 / 2 and / or, The cemented carbide is composed of tungsten-cobalt, tungsten-nickel or tungsten-nickel-cobalt cemented carbide; and / or, The matrix component of the amorphous alloy is a zirconium-based, zirconium-titanium-based or zirconium-niobium-based amorphous alloy, and the energy density per unit mass is greater than or equal to 5 KJ•g -1 , density is 7~12g / cm 3 , and the critical forming size of the matrix component of the amorphous alloy is greater than or equal to 0.1 mm, and the temperature upper and lower limit difference of the supercooled liquid phase region is greater than 40 K; the reinforcing phase component in the tungsten-containing amorphous alloy is tungsten particles.

3. The energetic composite connector according to claim 1, characterized in that: The length ratio of the head end penetration part to the tail end fragment part is 0.5-1.

5.

4. The energetic composite connector according to claim 1, characterized in that: The head end penetration part includes two areas, namely, a main penetration part at the head end and a secondary penetration part at the secondary head end, and the secondary penetration part at the secondary head end is configured to be a gradient cemented carbide material, the density of which increases gradually from the head to the tail, so that the overall center of gravity of the energetic composite connector moves backward and is close to the centroid of the energetic composite connector, thereby ensuring that the energetic composite connector flies stably; Preferably, the gradient is a structural gradient and / or a composition gradient; by regulating the content of the raw material components used in the preparation of the gradient cemented carbide or regulating the temperature field distribution during the sintering process when preparing the gradient cemented carbide, a sub-head end and sub-penetration part of the cemented carbide material with a gradient increase in density in the direction from the head to the tail is obtained.

5. The method for preparing an energetic composite connector according to any one of claims 1 to 4, characterized in that: The steps include: (1) roughening the surface of the cemented carbide block to be connected used in the head end penetration portion to obtain a roughened surface of the cemented carbide block to be connected in the head end penetration portion; (2) uniformly mixing the amorphous alloy powder and the tungsten reinforcement phase powder used in the tail fragment part to obtain the tungsten / amorphous alloy composite powder used in the tail fragment part; (3) directly performing spark plasma sintering to connect the tungsten / amorphous alloy composite powder of step (2) and the surface of the cemented carbide block to be connected after the roughening treatment of step (1) to obtain the energetic composite connecting part; or, First, the tungsten / amorphous alloy composite powder of step (2) is prepared into an amorphous alloy composite material block by spark plasma sintering, and then the surface to be connected is roughened to obtain the roughened surface of the amorphous alloy composite material block to be connected used by the tail end fragment part; then the roughened surface of the amorphous alloy composite material block to be connected used by the tail end fragment part is welded together with the roughened surface of the cemented carbide block to be connected used by the head end penetration part in step (1) to obtain the energetic composite connector.

6. The preparation method according to claim 5, characterized in that: The roughening treatments in step (1) and step (3) are independently one or more of sandpaper polishing and laser roughening; and / or, The roughness of the surface of the cemented carbide block to be connected used in the roughened head end penetration part is less than 2.5 μm; the roughness of the surface of the amorphous alloy composite material block to be connected used in the roughened tail end fragment part is less than 2.5 μm.

7. The preparation method according to claim 5, characterized in that: The volume fraction of the tungsten reinforcement phase powder in the tungsten / amorphous alloy composite powder is within a range of 20% to 60%.

8. The preparation method according to claim 5, characterized in that: Step (3) directly performing spark plasma sintering to connect the tungsten / amorphous alloy composite powder used in the tail end fragment part of step (2) and the surface to be connected of the cemented carbide block used in the roughened head end penetration part of step (1) by spark plasma sintering, the sintering temperature is set in the supercooled liquid phase region of the amorphous alloy, the sintering pressure is 50-150 MPa, the sintering time is 5-30 min, and the heating and cooling rate is 10-100 K / min; and / or, Step (3) preparing the tungsten / amorphous alloy composite powder used in the tail fragment part of step (2) into an amorphous alloy composite material block by spark plasma sintering, the sintering temperature is set in the supercooled liquid phase region of the amorphous alloy, the sintering pressure is 100-600 MPa, the sintering time is 5-30 min, and the heating and cooling rate is 20-200 K / min; and / or, In step (3), the amorphous alloy composite material block used in the roughened tail end fragment part and the surface to be connected of the cemented carbide block used in the roughened head end penetration part of step (1) are welded together, wherein the welding temperature is set to be 10-100 K below the glass transition end temperature Tx of the amorphous alloy, the welding pressure is 10-150 MPa, the welding time is 1-10 min, and the heating and cooling rate is 10-100 K / min.

9. The preparation method according to claim 4, characterized in that: The cemented carbide used in the head end penetration part of step (1) includes a main penetration part at the head end and a secondary penetration part at the sub-head end, and the secondary penetration part at the sub-head end uses a gradient cemented carbide with a density that increases gradually from the head end to the tail end; The preparation method of the gradient cemented carbide comprises the following steps: obtaining a secondary head end secondary penetration part cemented carbide material with a density gradient increasing from the head to the tail by regulating the content of raw material components used in the preparation of the gradient cemented carbide or regulating the temperature field distribution during the sintering process when preparing the gradient cemented carbide.

10. An armor-piercing fragmentation projectile, characterized in that: The core material thereof comprises the energetic composite connecting piece as claimed in any one of claims 1 to 4.

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