Tungsten alloy material, preparation method and application thereof

Abstract

The application provides a tungsten alloy material and a preparation method and application thereof, and the raw material of the tungsten alloy material comprises 90-93 wt% of tungsten, 0.1-1 wt% of an additive and a balance of a binder phase material in percentage by mass; the additive comprises any one or a combination of at least two of hafnium hydride, titanium hydride or zirconium hydride; the tungsten alloy material provided by the application has a tensile strength at room temperature of 1550 MPa or more, an elongation at room temperature of 10% or more and an impact toughness at room temperature of 80 J / cm 2 The above room temperature impact toughness is suitable for armor-piercing materials.

Description

Technical Field

[0001] This invention belongs to the field of alloy technology, and relates to an alloy material, particularly a tungsten alloy material and its preparation method and application. Background Technology

[0002] High-density tungsten alloys are a class of refractory metal alloy materials composed of refractory metal element tungsten and transition metal elements such as nickel, iron, cobalt, and copper. The microstructure of this material consists of a transition metal binder phase with refractory metal elements dissolved in solid solution and refractory metal particles. It has both structural and functional characteristics and has advantages such as high density, high strength, high hardness, high ductility, high toughness, and high dynamic mechanical properties, playing an important role in high-speed damage processes.

[0003] With the development and progress of modern technology, higher requirements have been placed on the comprehensive performance of high-density tungsten alloy materials, such as the need to have high density, ultra-high strength, high ductility and high toughness.

[0004] CN113881881A discloses a high-strength, high-toughness, high-density tungsten alloy material and its preparation method. The high-density tungsten alloy material has a density of 98.56-99.30%, a hardness of 408.72-435.79 HV, a tensile strength of 1250-1380 MPa, a tungsten content of 92.4-93 wt%, and the remainder consists of nickel, iron, cobalt, zirconium oxide, and unavoidable impurities. The mass ratio of nickel, iron, and cobalt is 3.85:1.65:1.5, and the zirconium oxide content is 0-0.6 wt%. The material is prepared by using reduced tungsten powder, hydroxyl nickel powder, hydroxyl iron powder, reduced cobalt powder, and nano-zirconia as raw materials, and sequentially undergoing ball milling and powder mixing, cold isostatic pressing, solid-state sintering, short-time liquid-phase sintering, dehydrogenation heat treatment, and rotary forging.

[0005] While the aforementioned methods can achieve a room-temperature tensile strength of 1280-1380 MPa in the obtained high-strength, high-toughness, high-specific-gravity tungsten alloy material, the tensile strength is still insufficient, and the room-temperature ductility and impact toughness are poor, indicating significant room for improvement in the material's overall performance. Therefore, there is a need to provide a tungsten alloy material with further improved tensile strength, while also possessing room-temperature ductility and impact toughness, along with its preparation method and applications. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a tungsten alloy material, its preparation method, and its application. The tungsten alloy material has good room temperature tensile strength, room temperature elongation at break, and room temperature impact toughness, and is suitable for armor-piercing materials.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a tungsten alloy material, wherein the raw materials for preparing the tungsten alloy material, by mass percentage, include 90-93 wt% tungsten, 0.1-1 wt% additives, and the balance being a binder phase material;

[0009] The additive includes any one or a combination of at least two of hafnium hydride, titanium hydride, or zirconium hydride. Typical but non-limiting combinations include combinations of hafnium hydride and titanium hydride, combinations of titanium hydride and zirconium hydride, combinations of hafnium hydride and zirconium hydride, or combinations of hafnium hydride, titanium hydride, and zirconium hydride.

[0010] In the tungsten alloy material provided by this invention, the mass percentage of tungsten is 90-93 wt%, for example, it can be 90 wt%, 90.5 wt%, 91 wt%, 91.5 wt%, 92 wt%, 92.5 wt%, or 93 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0011] In the tungsten alloy material provided by this invention, the mass percentage of the additive is 0.1-1 wt%, for example, it can be 0.1 wt%, 0.3 wt%, 0.5 wt%, 0.6 wt%, 0.8 wt%, or 1 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0012] The tungsten alloy material provided by this invention uses at least one of hafnium hydride, titanium hydride, or zirconium hydride as an additive. When mixed with tungsten and binder phase materials to prepare tungsten alloy materials, it has at least the following advantages: (a) During the heat treatment process of preparing tungsten alloy materials, the additive reacts with non-metallic impurity elements in other raw materials, purifies the interface of the alloy material, and improves the strength and toughness of the tungsten alloy material; (b) During the sintering process, the additive generates a trace amount of dispersed strengthening phase, refines the grain size of tungsten, and improves the strength of the tungsten alloy material; (c) During the preparation of tungsten alloy materials, the additive that does not react with non-metallic impurities decomposes to generate the corresponding metal, which dissolves in the binder phase and refines the grain size of tungsten, achieving a strengthening effect on the binder phase and tungsten, and improving the strength and toughness of the tungsten alloy material.

[0013] Preferably, the binder phase material comprises nickel and / or iron, and more particularly nickel and iron.

[0014] Preferably, the raw materials for preparing the tungsten alloy material, by mass percentage, include 90-93 wt% tungsten, 0.1-1 wt% additives, 3.5-7.5 wt% nickel, and 1.5-3.5 wt% iron.

[0015] In a second aspect, the present invention provides a method for preparing a tungsten alloy material as described in the first aspect, the method comprising the following steps:

[0016] The raw materials for preparing tungsten alloy material are mixed according to the formula, and then subjected to cold isostatic pressing, sintering, heat treatment and at least one rotary forging annealing treatment in sequence to obtain the tungsten alloy material.

[0017] The rotary forging annealing process includes rotary forging and annealing. When the cumulative deformation of the rotary forging is 25-50%, the annealing process is performed, and at least one rotary forging is performed after the last annealing process.

[0018] The cumulative deformation after the rotary forging and annealing treatment is more than 31%.

[0019] The preparation method provided by this invention involves annealing during rotary forging when the cumulative deformation reaches 25-50%. This process removes hydrogen dissolved in the material or non-metallic impurities segregated from the solution, eliminating hydrogen embrittlement and impurity segregation effects, and improving the ductility and toughness of the material. Furthermore, it removes the hardening effect during processing, reduces the material hardness, and releases stress. The rotary forging process provided by this invention is beneficial for increasing the processing deformation of the obtained tungsten alloy material, refining the microstructure, and thus improving the tensile strength and toughness of the tungsten alloy material.

[0020] Preferably, the tungsten particle size D50 in the raw materials is 0.5-5 μm.

[0021] Preferably, the particle size D50 of the additives in the preparation raw materials is 0.5-5 μm.

[0022] Preferably, the nickel in the raw materials has a particle size D50 of 0.5-5 μm.

[0023] Preferably, the iron in the raw materials has a particle size D50 of 0.5-5 μm.

[0024] Preferably, the pressure of the cold isostatic pressing is 150-300 MPa.

[0025] Preferably, the material obtained by cold isostatic pressing is a rod-shaped green billet.

[0026] Preferably, the sintering includes liquid phase sintering.

[0027] Preferably, the sintering temperature is 1400-1500℃ and the time is 60-180min.

[0028] Preferably, the sintering is carried out in a reducing atmosphere.

[0029] Preferably, the heat treatment temperature is 1000-1300℃, the time is 60-180min, and the absolute pressure is ≤1Pa.

[0030] Preferably, the temperature of the rotary forging is 450-650℃.

[0031] Preferably, the deformation amount per pass of the rotary forging is 8-15%.

[0032] Preferably, the annealing temperature is 800-1000℃, the holding time is 60-180min, and the absolute pressure is ≤1Pa.

[0033] Preferably, the preparation method includes the following steps:

[0034] (1) Mix the raw materials for preparing tungsten alloy materials according to the formula to obtain a mixture;

[0035] Among them, the particle size D50 of tungsten in the raw materials is 0.5-5μm, the particle size D50 of the additives is 0.5-5μm, the particle size D50 of nickel is 0.5-5μm, and the particle size D50 of iron is 0.5-5μm;

[0036] (2) The mixture obtained in step (1) is subjected to cold isostatic pressing at a pressure of 150-300 MPa to obtain a rod-shaped green body;

[0037] (3) The rod-shaped green blank obtained in step (2) is subjected to liquid phase sintering to obtain a sintered blank; the liquid phase sintering is carried out in a reducing atmosphere at a temperature of 1400-1500℃ for 60-180 min.

[0038] (4) The sintered billet obtained in step (3) is subjected to heat treatment, and then cooled after the heat treatment to obtain heat-treated bar stock; the heat treatment temperature is 1000-1300℃, the time is 60-180min, and the absolute pressure is ≤1Pa;

[0039] (5) Perform at least one rotary forging annealing treatment on the heat-treated bar obtained in step (4) to obtain the tungsten alloy material; the rotary forging annealing treatment includes rotary forging and annealing treatment, the rotary forging temperature is 450-650℃, and the single-pass deformation is 8-15%; when the cumulative deformation of the rotary forging is 25-50%, the annealing treatment is performed, and at least one rotary forging is performed after the last annealing treatment; the cumulative deformation after the rotary forging annealing treatment is more than 31%; the annealing temperature is 800-1000℃, the holding time is 60-180min, and the absolute pressure is ≤1Pa.

[0040] Thirdly, the present invention provides an application of the tungsten alloy material as described in the first aspect or the tungsten alloy material obtained by the preparation method described in the second aspect, wherein the tungsten alloy material is used as an armor-piercing material.

[0041] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0042] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0043] (1) The tungsten alloy material provided by the present invention uses at least one of hafnium hydride, titanium hydride or zirconium hydride as an additive. When it is mixed with tungsten and binder phase material to prepare tungsten alloy material, it has at least the following advantages: (a) During the heat treatment process of preparing tungsten alloy material, the additive reacts with non-metallic impurity elements in other raw materials, purifies the interface of the alloy material, and improves the strength and toughness of tungsten alloy material; (b) During the sintering process, the additive generates a trace amount of dispersed strengthening phase, refines the grain size of tungsten, and improves the strength of tungsten alloy material; (c) During the preparation of tungsten alloy material, the additive that does not react with non-metallic impurities decomposes to generate the corresponding metal, which dissolves in the binder phase and refines the grain size of tungsten, thereby achieving a strengthening effect on the binder phase and tungsten, and improving the strength and toughness of tungsten alloy material;

[0044] (2) The preparation method provided by the present invention performs annealing when the cumulative deformation reaches 25-50%. On the one hand, it can remove hydrogen dissolved in the material or non-metallic impurities segregated by solid solution, eliminate hydrogen embrittlement and impurity segregation effects, and improve the ductility and toughness of the material. On the other hand, it can remove the hardening effect during the processing, reduce the hardness of the material, and release stress. The rotary forging process provided by the present invention is beneficial to increasing the processing deformation of the obtained tungsten alloy material, refining the microstructure, thereby improving the tensile strength and toughness of the tungsten alloy material. Detailed Implementation

[0045] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0046] Some embodiments of the present invention provide a tungsten alloy material, wherein the raw materials for preparing the tungsten alloy material, by mass percentage, include 90-93 wt% tungsten, 0.1-1 wt% additives, and the balance being a binder phase material;

[0047] The additive includes any one or a combination of at least two of hafnium hydride, titanium hydride, or zirconium hydride. Typical but non-limiting combinations include combinations of hafnium hydride and titanium hydride, combinations of titanium hydride and zirconium hydride, combinations of hafnium hydride and zirconium hydride, or combinations of hafnium hydride, titanium hydride, and zirconium hydride.

[0048] In the tungsten alloy material provided by this invention, the mass percentage of tungsten is 90-93 wt%, for example, it can be 90 wt%, 90.5 wt%, 91 wt%, 91.5 wt%, 92 wt%, 92.5 wt%, or 93 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0049] In the tungsten alloy material provided by the present invention, the mass percentage of the additive is 0.1-1 wt%, for example, it can be 0.1 wt%, 0.3 wt%, 0.5 wt%, 0.6 wt%, 0.8 wt% or 1 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 0.2-0.8 wt%.

[0050] In actual production, it is difficult to achieve 100% purity in the raw materials used to produce tungsten alloy materials, so there will be unavoidable impurities, such as C and O.

[0051] The tungsten alloy material provided by this invention uses at least one of hafnium hydride, titanium hydride, or zirconium hydride as an additive. When mixed with tungsten and binder phase materials to prepare tungsten alloy materials, it has at least the following advantages: (a) During the heat treatment process of preparing tungsten alloy materials, the additive reacts with non-metallic impurity elements such as C and O in other raw materials, purifying the interface of the alloy material and improving the strength and toughness of the tungsten alloy material; (b) During the sintering process, the additive generates a trace amount of dispersed strengthening phase, refining the grain size of tungsten and improving the strength of the tungsten alloy material; (c) During the preparation of tungsten alloy materials, the additive that does not react with non-metallic impurities decomposes to generate the corresponding metal, which dissolves in the binder phase and refines the grain size of tungsten, achieving a strengthening effect on the binder phase and tungsten, and improving the strength and toughness of the tungsten alloy material.

[0052] Taking hafnium hydride as an additive as an example, when it is mixed with tungsten and binder phase materials to prepare tungsten alloy materials, it has at least the following advantages: (a) During the heat treatment process of preparing tungsten alloy materials, hafnium hydride reacts with non-metallic impurity elements such as C and O in other raw materials to generate trace amounts of HfC, HfO2, etc., which purifies the interface of the alloy material and improves the strength and toughness of the tungsten alloy material; (b) During the sintering process, hafnium hydride generates dispersed strengthening phases such as trace amounts of HfC, HfO2, etc., which refines the grain size of tungsten and improves the strength of the tungsten alloy material; (c) During the preparation of tungsten alloy materials, hafnium hydride that has not reacted with non-metallic impurities will decompose to generate hafnium, which dissolves in the binder phase and refines the grain size of tungsten, achieving a strengthening effect on the binder phase and tungsten, and improving the strength and toughness of the tungsten alloy material.

[0053] In some embodiments, the binder phase material comprises nickel and / or iron, preferably nickel and iron.

[0054] In some embodiments, the raw materials for preparing the tungsten alloy material, by mass percentage, include 90-93 wt% tungsten, 0.1-1 wt% additives, 3.5-7.5 wt% nickel, and 1.5-3.5 wt% iron.

[0055] In the raw materials for preparing the tungsten alloy material, the mass percentage of tungsten is 90-93 wt%, for example, it can be 90 wt%, 90.5 wt%, 91 wt%, 91.5 wt%, 92 wt%, 92.5 wt%, or 93 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0056] The raw materials for preparing the tungsten alloy material include tungsten components and unavoidable impurities. Preferably, the purity of the tungsten is ≥99.5wt%.

[0057] In the raw materials for preparing the tungsten alloy material, the mass percentage of the additive is 0.1-1 wt%, for example, it can be 0.1 wt%, 0.3 wt%, 0.5 wt%, 0.6 wt%, 0.8 wt%, or 1 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 0.2-0.8 wt%.

[0058] The raw materials for preparing the tungsten alloy material include additive components and unavoidable impurities. Preferably, the purity of the additive is ≥99.5wt%.

[0059] In the raw materials for preparing the tungsten alloy material, the mass percentage of nickel is 3.5-7.5 wt%, for example, it can be 3.5 wt%, 4.0 wt%, 4.5 wt%, 5.0 wt%, 5.5 wt%, 6.0 wt%, 6.5 wt%, 7.0 wt%, or 7.5 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0060] In the raw materials for preparing the tungsten alloy material, the nickel composition includes nickel components and unavoidable impurities. Preferably, the purity of the nickel is ≥99.5wt%.

[0061] In the raw materials for preparing the tungsten alloy material, the mass percentage of iron is 1.5-3.5 wt%, for example, it can be 1.5 wt%, 2.0 wt%, 2.5 wt%, 3.0 wt%, or 3.5 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0062] In the raw materials for preparing the tungsten alloy material, the iron composition includes iron components and unavoidable impurities. Preferably, the purity of the iron is ≥99.5wt%.

[0063] One embodiment of the present invention provides a method for preparing tungsten alloy materials in certain embodiments, the method comprising the following steps:

[0064] The raw materials for preparing tungsten alloy material are mixed according to the formula, and then subjected to cold isostatic pressing, sintering, heat treatment and at least one rotary forging annealing treatment in sequence to obtain the tungsten alloy material.

[0065] The rotary forging annealing process includes rotary forging and annealing. When the cumulative deformation of the rotary forging is 25-50%, the annealing process is performed, and at least one rotary forging is performed after the last annealing process.

[0066] The cumulative deformation after the rotary forging and annealing treatment is more than 31%.

[0067] The preparation method provided by this invention involves annealing during rotary forging when the cumulative deformation reaches 25-50%. This process removes hydrogen dissolved in the material or non-metallic impurities segregated from the solution, eliminating hydrogen embrittlement and impurity segregation effects, and improving the ductility and toughness of the material. Furthermore, it removes the hardening effect during processing, reduces the material hardness, and releases stress. The rotary forging process provided by this invention is beneficial for increasing the processing deformation of the obtained tungsten alloy material, refining the microstructure, and thus improving the tensile strength and toughness of the tungsten alloy material.

[0068] The present invention can employ multiple rotary forging and annealing processes as needed. Taking two rotary forging and annealing processes as an example, the entire process of two rotary forging and annealing processes includes a first rotary forging, a first annealing process, a second rotary forging, a second annealing process, and at least one final rotary forging.

[0069] When performing annealing, the cumulative deformation of rotary forging is 25-50%, for example, it can be 25%, 30%, 35%, 40%, 45% or 50%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 25-46%.

[0070] The cumulative deformation after rotary forging annealing is 31% or more, for example, it can be 31%, 35%, 40%, 44%, 45%, 50%, 55%, 60%, 64%, 66% or 70%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0071] Let S1 be the cross-sectional area of ​​the heat-treated bar billet and S2 be the cross-sectional area of ​​the forged bar. Then the cumulative deformation is [(S1-S2) / S1]×100%.

[0072] In some embodiments, the particle size D50 of tungsten in the raw materials is 0.5-5 μm, for example, it can be 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm or 5 μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0073] In some embodiments, the particle size D50 of the additive in the preparation raw materials is 0.5-5 μm, for example, it can be 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm or 5 μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0074] In some embodiments, the nickel particle size D50 in the raw materials is 0.5-5 μm, for example, it can be 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm or 5 μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0075] In some embodiments, the particle size D50 of iron in the raw materials is 0.5-5 μm, for example, it can be 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm or 5 μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0076] In some embodiments, the pressure of the cold isostatic pressing is 150-300 MPa, for example, it can be 150 MPa, 180 MPa, 200 MPa, 240 MPa, 250 MPa, 270 MPa or 300 MPa, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0077] In some embodiments, the material obtained by cold isostatic pressing is a rod-shaped green billet.

[0078] In some embodiments, the diameter of the rod-shaped green billet is 5-150 mm, for example, it can be 5 mm, 10 mm, 30 mm, 50 mm, 60 mm, 80 mm, 100 mm, 120 mm or 150 mm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0079] In some embodiments, the sintering includes liquid-phase sintering.

[0080] In some embodiments, the sintering temperature is 1400-1500°C and the time is 60-180 min.

[0081] The sintering temperature described in this invention is 1400-1500℃, for example, it can be 1400℃, 1430℃, 1450℃, 1480℃ or 1500℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 1410-1485℃.

[0082] The sintering time described in this invention is 60-180 min, for example, it can be 60 min, 80 min, 100 min, 120 min, 150 min, 160 min or 180 min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 90-150 min.

[0083] In some embodiments, the sintering is performed in a reducing atmosphere.

[0084] The reducing atmosphere used in this invention includes CO and / or H2.

[0085] In some embodiments, the heat treatment is performed at a temperature of 1000-1300°C for 60-180 minutes, with an absolute pressure ≤1 Pa.

[0086] In this invention, the heat treatment temperature is 1000-1300℃, for example, it can be 1000℃, 1050℃, 1100℃, 1150℃, 1200℃, 1250℃ or 1300℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 1030-1285℃.

[0087] The heat treatment time in this invention is 60-180 min, for example, it can be 60 min, 80 min, 100 min, 120 min, 150 min, 160 min or 180 min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0088] In this invention, the absolute pressure of heat treatment is ≤1Pa, for example, it can be 0.1Pa, 0.3Pa, 0.5Pa, 0.8Pa or 1Pa, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0089] The preparation method of the present invention also includes cooling after heat treatment and before rotary forging, and the cooling method includes, but is not limited to, oil cooling and / or water cooling.

[0090] In some embodiments, the forging temperature is 450-650°C, for example, it can be 450°C, 480°C, 500°C, 540°C, 550°C, 560°C, 600°C, 640°C or 650°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 460-630°C.

[0091] In some embodiments, the deformation per pass of the rotary forging is 8-15%, for example, it can be 8%, 10%, 12%, 14% or 15%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 9-15%.

[0092] The "single-pass deformation amount of rotary forging" described in this invention is based on the dimensions before single-pass deformation. The original bar diameter is 50 mm, i.e., the original bar cross-sectional area is 1963 mm². 2 The bar undergoes four passes of rotary forging, with a deformation of 10% per pass. The cross-sectional area of ​​the bar after each pass is 1767 mm². 2 1590mm 2 1431mm 2 1288mm 2 That is, the diameters after each forging pass are 47.43mm, 45.00mm, 42.69mm, and 40.50mm, respectively; at this point, the cumulative deformation is 34.39%.

[0093] In some embodiments, the annealing treatment is performed at a temperature of 800-1000°C, a holding time of 60-180 min, and an absolute pressure of ≤1 Pa.

[0094] In this invention, the annealing temperature is 800-1000℃, for example, it can be 800℃, 850℃, 900℃, 950℃ or 1000℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, with 850-1000℃ being the preferred temperature.

[0095] In this invention, the holding time for annealing is 60-180 min, for example, it can be 60 min, 80 min, 100 min, 120 min, 150 min, 160 min or 180 min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0096] In this invention, the absolute pressure of the annealing treatment is ≤1Pa, for example, it can be 0.1Pa, 0.3Pa, 0.5Pa, 0.8Pa or 1Pa, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0097] In some embodiments, the preparation method includes the following steps:

[0098] (1) Mix the raw materials for preparing tungsten alloy materials according to the formula to obtain a mixture;

[0099] Among them, the particle size D50 of tungsten in the raw materials is 0.5-5μm, the particle size D50 of the additives is 0.5-5μm, the particle size D50 of nickel is 0.5-5μm, and the particle size D50 of iron is 0.5-5μm;

[0100] (2) The mixture obtained in step (1) is subjected to cold isostatic pressing at a pressure of 150-300 MPa to obtain a rod-shaped green body;

[0101] (3) The rod-shaped green blank obtained in step (2) is subjected to liquid phase sintering to obtain a sintered blank; the liquid phase sintering is carried out in a reducing atmosphere at a temperature of 1400-1500℃ for 60-180 min.

[0102] (4) The sintered billet obtained in step (3) is subjected to heat treatment, and then cooled after the heat treatment to obtain heat-treated bar stock; the heat treatment temperature is 1000-1300℃, the time is 60-180min, and the absolute pressure is ≤1Pa;

[0103] (5) Perform at least one rotary forging annealing treatment on the heat-treated bar obtained in step (4) to obtain the tungsten alloy material; the rotary forging annealing treatment includes rotary forging and annealing treatment, the rotary forging temperature is 450-650℃, and the single-pass deformation is 8-15%; when the cumulative deformation of the rotary forging is 25-50%, the annealing treatment is performed, and at least one rotary forging is performed after the last annealing treatment, and the cumulative deformation after the rotary forging annealing treatment is more than 31%; the annealing treatment temperature is 800-1000℃, the holding time is 60-180min, and the absolute pressure is ≤1Pa.

[0104] One embodiment of the present invention provides the application of tungsten alloy materials in certain embodiments, said tungsten alloy materials being used as armor-piercing materials.

[0105] The tungsten alloy material provided by this invention has a room temperature tensile strength of over 1550 MPa, a room temperature elongation at break of over 10%, and an elongation at break of 80 J / cm. 2 The above room temperature impact toughness is applicable to armor-piercing materials.

[0106] Example 1

[0107] This embodiment provides a tungsten alloy material, wherein the raw materials for preparing the tungsten alloy material include 91.5 wt% tungsten powder, 2.39 wt% iron powder, 5.59 wt% nickel powder, and 0.52 wt% hafnium hydride, by mass percentage.

[0108] The hafnium hydride has a purity of 99.8 wt% and a particle size D50 of 1.1 μm.

[0109] The tungsten powder has a purity of 99.9 wt% and a particle size D50 of 3.5 μm.

[0110] The iron powder has a purity of 99.9 wt% and a particle size D50 of 1.8 μm.

[0111] The nickel powder has a purity of 99.9 wt% and a particle size D50 of 1.2 μm.

[0112] The tungsten alloy material provided in this embodiment is obtained by the following preparation method, which includes the following steps:

[0113] (1) Mix the raw materials for preparing tungsten alloy materials according to the formula to obtain a mixture;

[0114] (2) The mixture obtained in step (1) is subjected to cold isostatic pressing at a pressure of 200 MPa to obtain a rod-shaped green body with a diameter of 50 mm.

[0115] (3) The rod-shaped green blank obtained in step (2) is subjected to liquid phase sintering to obtain a sintered blank; the liquid phase sintering is carried out in a hydrogen atmosphere at a temperature of 1461℃ for 90 min.

[0116] (4) The sintered billet obtained in step (3) is subjected to heat treatment. After the heat treatment is completed, it is placed in oil for rapid cooling to obtain heat-treated bar stock. The heat treatment temperature is 1283℃, the time is 120min, and the absolute pressure is 0.5Pa.

[0117] (5) The heat-treated bar obtained in step (4) is subjected to rotary forging and annealing to obtain the tungsten alloy material. The rotary forging temperature is 577℃, the single-pass deformation is 11.4%, and after 4 passes of rotary forging, the cumulative deformation is 38.4%. Then, annealing is performed at a temperature of 862℃, a holding time of 114 min, and an absolute pressure of 0.4 Pa. The annealed bar is then subjected to rotary forging at a temperature of 577℃, the single-pass deformation is 11.4%, and the cumulative deformation after rotary forging and annealing is 62.0%.

[0118] Example 2

[0119] This embodiment provides a tungsten alloy material, wherein the raw materials for preparing the tungsten alloy material include 92.4 wt% tungsten powder, 3.39 wt% iron powder, 3.98 wt% nickel powder, and 0.23 wt% hafnium hydride, by mass percentage.

[0120] The hafnium hydride has a purity of 99.8 wt% and a particle size D50 of 4.6 μm.

[0121] The tungsten powder has a purity of 99.5 wt% and a particle size D50 of 5.0 μm.

[0122] The iron powder has a purity of 99.7 wt% and a particle size D50 of 2.5 μm.

[0123] The nickel powder has a purity of 99.95 wt% and a particle size D50 of 2.8 μm.

[0124] The tungsten alloy material provided in this embodiment is obtained by the following preparation method, which includes the following steps:

[0125] (1) Mix the raw materials for preparing tungsten alloy materials according to the formula to obtain a mixture;

[0126] (2) The mixture obtained in step (1) is subjected to cold isostatic pressing at a pressure of 150 MPa to obtain a rod-shaped green body with a diameter of 50 mm.

[0127] (3) The rod-shaped green blank obtained in step (2) is subjected to liquid phase sintering to obtain a sintered blank; the liquid phase sintering is carried out in a hydrogen atmosphere at a temperature of 1484℃ for 150 min.

[0128] (4) The sintered billet obtained in step (3) is subjected to heat treatment, and after the heat treatment is completed, it is placed in water for rapid cooling to obtain heat-treated bar stock; the heat treatment temperature is 1113℃, the time is 165min, and the absolute pressure is 0.8Pa.

[0129] (5) The heat-treated bar obtained in step (4) is subjected to rotary forging annealing to obtain the tungsten alloy material. The rotary forging temperature is 462℃, the single-pass deformation is 9.3%, and after 3 passes of rotary forging, the cumulative deformation is 25.4%. Then, annealing is performed at a temperature of 977℃, a holding time of 162 min, and an absolute pressure of 0.3 Pa. The annealed bar is then subjected to rotary forging at a temperature of 462℃, the single-pass deformation is 9.3%, and the cumulative deformation after rotary forging annealing is 44.3%.

[0130] Example 3

[0131] This embodiment provides a tungsten alloy material, which, by mass percentage, comprises 90.3 wt% tungsten powder, 1.61 wt% iron powder, 7.31 wt% nickel powder, and 0.78 wt% hafnium hydride.

[0132] The hafnium hydride has a purity of 99.8 wt% and a particle size D50 of 2.3 μm.

[0133] The tungsten powder has a purity of 99.99 wt% and a particle size D50 of 0.8 μm.

[0134] The iron powder has a purity of 99.93 wt% and a particle size D50 of 4.4 μm.

[0135] The nickel powder has a purity of 99.5 wt% and a particle size D50 of 4.1 μm.

[0136] The tungsten alloy material provided in this embodiment is obtained by the following preparation method, which includes the following steps:

[0137] (1) Mix the raw materials for preparing tungsten alloy materials according to the formula to obtain a mixture;

[0138] (2) The mixture obtained in step (1) is subjected to cold isostatic pressing at a pressure of 300 MPa to obtain a rod-shaped green body with a diameter of 50 mm.

[0139] (3) The rod-shaped green blank obtained in step (2) is subjected to liquid phase sintering to obtain a sintered blank; the liquid phase sintering is carried out in a hydrogen atmosphere at a temperature of 1415℃ for 115 min.

[0140] (4) The sintered billet obtained in step (3) is subjected to heat treatment. After the heat treatment is completed, it is placed in oil for rapid cooling to obtain heat-treated bar stock. The heat treatment temperature is 1035℃, the time is 92min, and the absolute pressure is 0.2Pa.

[0141] (5) The heat-treated bar obtained in step (4) is subjected to rotary forging annealing to obtain the tungsten alloy material; the rotary forging temperature is 628℃, the single-pass deformation is 14.2%, and after 4 passes of rotary forging, the cumulative deformation is 45.8%. Then, annealing is performed at a temperature of 902℃, a holding time of 88 min, and an absolute pressure of 0.7 Pa. The annealed bar is then subjected to rotary forging at a temperature of 628℃, the single-pass deformation is 14.2%, and the cumulative deformation after rotary forging annealing is 53.5%.

[0142] Example 4

[0143] This embodiment provides a tungsten alloy material, which is the same as in Embodiment 1 except that hafnium hydride is replaced by titanium hydride.

[0144] Example 5

[0145] This embodiment provides a tungsten alloy material, which is the same as in Embodiment 1 except that hafnium hydride is replaced by zirconium hydride.

[0146] Example 6

[0147] This embodiment provides a tungsten alloy material, the raw material composition of which is the same as that in Embodiment 1;

[0148] The tungsten alloy material provided in this embodiment is obtained by the following preparation method, which includes the following steps:

[0149] (1) Mix the raw materials for preparing tungsten alloy materials according to the formula to obtain a mixture;

[0150] (2) The mixture obtained in step (1) is subjected to cold isostatic pressing at a pressure of 200 MPa to obtain a rod-shaped green body with a diameter of 50 mm.

[0151] (3) The rod-shaped green blank obtained in step (2) is subjected to liquid phase sintering to obtain a sintered blank; the liquid phase sintering is carried out in a hydrogen atmosphere at a temperature of 1461℃ for 90 min.

[0152] (4) The sintered billet obtained in step (3) is subjected to heat treatment. After the heat treatment is completed, it is placed in oil for cooling to obtain heat-treated bar stock. The heat treatment temperature is 1283℃, the time is 120min, and the absolute pressure is 0.5Pa.

[0153] (5) The heat-treated bar obtained in step (4) is subjected to rotary forging annealing to obtain the tungsten alloy material; the rotary forging temperature is 577℃, the single-pass deformation is 11.4%, and after 6 passes of rotary forging, the cumulative deformation is 51.6%. Then, annealing is performed at a temperature of 862℃, a holding time of 114 min, and an absolute pressure of 0.4 Pa. The annealed bar is then subjected to rotary forging at a temperature of 577℃, the single-pass deformation is 11.4%, and the cumulative deformation after rotary forging annealing is 62.0%.

[0154] Comparative Example 1

[0155] This comparative example provides a tungsten alloy material, which is the same as that in Example 1 except that hafnium hydride was not added in the raw materials.

[0156] Comparative Example 2

[0157] This comparative example provides a tungsten alloy material that is identical to Example 1 except that no annealing treatment is performed during the rotary forging process.

[0158] Comparative Example 3

[0159] This embodiment provides a tungsten alloy material, which, by mass percentage, is the same as in Example 1 except that the raw materials for preparing the tungsten alloy material include 91.5 wt% tungsten powder, 2.19 wt% iron powder, 5.12 wt% nickel powder, and 1.19 wt% hafnium hydride.

[0160] Comparative Example 4

[0161] This embodiment provides a tungsten alloy material, which, by mass percentage, is the same as in Example 1 except that the raw materials for preparing the tungsten alloy material include 91.5 wt% tungsten powder, 2.53 wt% iron powder, 5.91 wt% nickel powder, and 0.06 wt% hafnium hydride.

[0162] Performance Characterization

[0163] The density, compactness, average tungsten grain size, room temperature tensile strength, room temperature elongation after fracture, and room temperature impact toughness of the tungsten alloy materials provided in Examples 1-6 and Comparative Examples 1-4 were tested, and the results are shown in Table 1.

[0164] The density and compactness test methods refer to the standard "ASTM B311-2008 Standard Test Method for Density of Powder Metallurgical Materials with Porosity Less Than 2%" and are conducted using the Archimedes' drainage method.

[0165] The average size of tungsten grains was determined using a metallographic microscope in accordance with the standard ASTM E112-13 (2021) Standard Test Method for Determining Average Grain Size; the room temperature tensile strength and room temperature elongation after fracture were determined using a universal testing machine in accordance with the standard GB / T 228.1-2010 Metallic Materials - Tensile Testing - Part 1: Room Temperature Test Method.

[0166] The room temperature impact toughness test method is based on the standard GB / T 9096-2002 "Impact Test Method for Sintered Metal Materials (excluding cemented carbides)" and is conducted using an impact toughness testing machine.

[0167] Table 1

[0168]

[0169] In summary, the tungsten alloy material provided by this invention uses at least one of hafnium hydride, titanium hydride, or zirconium hydride as an additive. When mixed with tungsten and binder phase materials to prepare tungsten alloy materials, it has at least the following advantages: (a) During the heat treatment process of preparing the tungsten alloy material, the additive reacts with non-metallic impurity elements in other raw materials, purifying the interface of the alloy material and improving the strength and toughness of the tungsten alloy material; (b) During the sintering process, the additive generates trace amounts of dispersed strengthening phases, refining the grain size of tungsten and improving the strength of the tungsten alloy material; (c) During the preparation of the tungsten alloy material, the additive that does not react with non-metallic impurities decomposes to generate the corresponding metal. The tungsten alloy is dissolved in the binder phase and its grain size is refined, thus strengthening both the binder phase and the tungsten, and improving the strength and toughness of the tungsten alloy. The preparation method provided by this invention involves annealing when the cumulative deformation reaches 25-50%. This process removes hydrogen dissolved in the material or non-metallic impurities segregated from the solution, eliminating hydrogen embrittlement and impurity segregation effects, and improving the ductility and toughness of the material. On the other hand, it removes the hardening effect during processing, reduces the material hardness, and releases stress. The rotary forging process provided by this invention is beneficial for increasing the processing deformation of the obtained tungsten alloy and refining the microstructure, thereby improving the tensile strength and toughness of the tungsten alloy.

[0170] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A tungsten alloy material, characterized in that, The raw materials for preparing the tungsten alloy material, by mass percentage, consist of 90-93 wt% tungsten, 0.1-1 wt% additives, and the balance being binder phase material. The additives include any one or a combination of at least two of hafnium hydride, titanium hydride, or zirconium hydride. The tungsten alloy material is prepared by the following method, the preparation method comprising: The raw materials for preparing tungsten alloy material are mixed according to the formula, and then subjected to cold isostatic pressing, sintering, heat treatment and at least one rotary forging annealing treatment in sequence to obtain the tungsten alloy material. The rotary forging annealing process includes rotary forging and annealing. When the cumulative deformation of the rotary forging is 25-50%, the annealing process is performed, and at least one rotary forging is performed after the last annealing process. The cumulative deformation after the rotary forging and annealing treatment is more than 31%.

2. The tungsten alloy material according to claim 1, characterized in that, The binder phase material includes nickel and / or iron.

3. The tungsten alloy material according to claim 2, characterized in that, The raw materials for preparing the tungsten alloy material, by mass percentage, include 90-93 wt% tungsten, 0.1-1 wt% additives, 3.5-7.5 wt% nickel, and 1.5-3.5 wt% iron.

4. A method for preparing a tungsten alloy material as described in any one of claims 1-3, characterized in that, The preparation method includes the following steps: The raw materials for preparing tungsten alloy materials are mixed according to the formula, and then subjected to cold isostatic pressing, sintering, heat treatment and at least one rotary forging annealing treatment in sequence to obtain the tungsten alloy material. The rotary forging annealing process includes rotary forging and annealing. When the cumulative deformation of the rotary forging is 25-50%, the annealing process is performed, and at least one rotary forging is performed after the last annealing process. The cumulative deformation after the rotary forging and annealing treatment is more than 31%.

5. The preparation method according to claim 4, characterized in that, The tungsten in the prepared raw materials has a particle size D50 of 0.5-5 μm.

6. The preparation method according to claim 4, characterized in that, In the raw materials used for preparation, the particle size D50 of the additives is 0.5-5 μm.

7. The preparation method according to claim 6, characterized in that, In the raw materials used for preparation, the particle size D50 of nickel is 0.5-5 μm.

8. The preparation method according to claim 6, characterized in that, The iron in the prepared raw materials has a particle size D50 of 0.5-5 μm.

9. The preparation method according to claim 4, characterized in that, The pressure of the cold isostatic pressing is 150-300 MPa.

10. The preparation method according to claim 4, characterized in that, The material obtained by cold isostatic pressing is a rod-shaped green billet.

11. The preparation method according to claim 4, characterized in that, The sintering includes liquid phase sintering.

12. The preparation method according to claim 4, characterized in that, The sintering temperature is 1400-1500℃ and the time is 60-180min.

13. The preparation method according to claim 4, characterized in that, The sintering is carried out in a reducing atmosphere.

14. The preparation method according to claim 4, characterized in that, The heat treatment temperature is 1000-1300℃, the time is 60-180min, and the absolute pressure is ≤1Pa.

15. The preparation method according to claim 4, characterized in that, The temperature of the rotary forging is 450-650℃.

16. The preparation method according to claim 4, characterized in that, The deformation amount per pass in the rotary forging is 8-15%.

17. The preparation method according to claim 4, characterized in that, The annealing treatment is performed at a temperature of 800-1000℃, a holding time of 60-180 min, and an absolute pressure of ≤1 Pa.

18. The preparation method according to claim 4, characterized in that, The preparation method includes the following steps: (1) Mix the raw materials for the preparation of tungsten alloy materials according to the formula to obtain a mixture; Among them, the particle size D50 of tungsten in the raw materials is 0.5-5μm, the particle size D50 of the additives is 0.5-5μm, the particle size D50 of nickel is 0.5-5μm, and the particle size D50 of iron is 0.5-5μm; (2) The mixture obtained in step (1) is subjected to cold isostatic pressing at a pressure of 150-300 MPa to obtain a rod-shaped green body; (3) The rod-shaped green billet obtained in step (2) is subjected to liquid phase sintering to obtain a sintered billet; the liquid phase sintering is carried out in a reducing atmosphere at a temperature of 1400-1500℃ for a time of 60-180min. (4) The sintered billet obtained in step (3) is subjected to heat treatment, and then cooled after the heat treatment to obtain heat-treated bar stock; the heat treatment temperature is 1000-1300℃, the time is 60-180min, and the absolute pressure is ≤1Pa; (5) Perform at least one rotary forging annealing treatment on the heat-treated bar obtained in step (4) to obtain the tungsten alloy material; the rotary forging annealing treatment includes rotary forging and annealing treatment, the rotary forging temperature is 450-650℃, and the single-pass deformation is 8-15%; when the cumulative deformation of the rotary forging is 25-50%, the annealing treatment is performed, and at least one rotary forging is performed after the last annealing treatment, and the cumulative deformation after the rotary forging annealing treatment is more than 31%; the annealing temperature is 800-1000℃, the holding time is 60-180min, and the absolute pressure is ≤1Pa.

19. The application of a tungsten alloy material as described in any one of claims 1-3 or a tungsten alloy material obtained by the preparation method as described in any one of claims 4-18, characterized in that, The tungsten alloy material is used as armor-piercing material.

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