A heat treatment method for a tungsten-tantalum-nickel-iron-copper alloy

Abstract

The application discloses a heat treatment method of a tungsten-tantalum-nickel-iron-copper alloy. The tungsten-tantalum-nickel-iron-copper alloy sintered body is subjected to high-temperature heat treatment at 1100-1250 DEG C, immediately subjected to oil quenching after the high-temperature heat treatment, then subjected to low-temperature heat treatment at 400-500 DEG C, and immediately subjected to water quenching after the low-temperature heat treatment. Through the heat treatment, the NiTa strengthening phase in the matrix is refined, the binder phase maintains a gamma-(Ni, Fe, Cu) solid solution phase structure at room temperature, the binder phase and the matrix phase are in a good coherent relationship, and the strength and toughness of the tungsten-tantalum-nickel-iron-copper alloy after the heat treatment are greatly improved.

Description

Technical Field

[0001] This invention belongs to the field of heat treatment of tungsten alloys, and specifically relates to a heat treatment method for tungsten-tantalum-nickel-iron-copper alloys. Background Technology

[0002] Tungsten alloys, as an important material for military and defense weaponry, are the preferred choice for armor-piercing projectiles and protective materials due to their high strength, high toughness, and high density. Traditional tungsten alloys are W-Ni-Fe based, with a typical 90W-7Ni-3Fe alloy achieving a strength of only 0.9 GPa, significantly limiting their applications. High-strength, ultrafine-grained tungsten-tantalum-nickel-iron-copper alloys, obtained through second-phase strengthening, can achieve a strength of 1.1 GPa, but their toughness decreases significantly. However, extreme service environments require tungsten alloys to maintain good toughness while possessing high strength. Therefore, synergistic enhancement of strength and toughness has become an important direction for the development of tungsten alloys. Heat treatment can significantly improve the toughness of steel and aluminum-based materials, but due to tungsten's highest melting point among metals, traditional heat treatment methods are almost ineffective for conventional tungsten alloys. However, tungsten-tantalum-nickel-iron-copper alloys not only contain low-melting-point copper but also a NiTa strengthening phase in the matrix phase, which is the main reason for the decrease in toughness. Therefore, by controlling the dissolution and precipitation of copper and NiTa strengthening phases through heat treatment, and thus controlling their morphology and size, the toughness of tungsten-tantalum-nickel-iron-copper alloys can be significantly improved.

[0003] 202211020238.1 A high-strength, ultrafine-grained tungsten-tantalum-nickel-iron-copper alloy, its preparation method, and its application, wherein the alloy composition is disclosed as follows: by mass ratio, tungsten-tantalum pre-alloy powder: nickel powder: iron powder: copper powder = 90:3.5-6.3:1.5-2.7:1-5; in the tungsten-tantalum pre-alloy powder, the mass ratio of tungsten to tantalum is 85-95:5-15; the tungsten-tantalum pre-alloy powder is obtained by: mixing tungsten powder and tantalum powder, ball milling to obtain coarse tungsten-tantalum pre-alloy powder, then drying the coarse tungsten-tantalum pre-alloy powder under vacuum, and then reducing it to obtain tungsten-tantalum pre-alloy powder; the tungsten powder is polyhedral or spherical powder with an average particle size of 3-5 μm. The purity is ≥99.8%; the tantalum powder is spherical powder with an average particle size of 25-35μm and a purity ≥99.5%; the nickel powder is spherical powder with an average particle size of 3-5μm and a purity ≥99.9%; the iron powder is spherical powder with an average particle size of 3-5μm and a purity ≥99.5%; the copper powder is spherical powder with an average particle size of 3-5μm and a purity ≥99.8%. The tungsten-tantalum-nickel-iron-copper alloy is composed of an alloy matrix and a NiTa reinforcing phase. The particle size of the alloy matrix is ​​≤10μm, and the particle size of the NiTa reinforcing phase is 100-200nm. The density of the tungsten-tantalum-nickel-iron-copper alloy is ≥97.89%, and the tensile strength is ≥900MPa.

[0004] The main feature of this patent is that it significantly improves the tensile strength of the tungsten alloy while ensuring its high density. In Example 1, the tungsten-tantalum-nickel-iron-copper alloy has an average density of 16.75 g / cm3, an average relative density of 97.89%, an average elongation of 17.11%, an average tensile strength of 1100 MPa, and an average grain size of 6.83 micrometers.

[0005] The shortcomings of this patent are: although the presence of the reinforcing phase significantly improves the tensile strength of the alloy, the large size of the NiTa reinforcing phase leads to a decrease in the toughness of the matrix phase and a significant decrease in the elongation of the alloy. The strength-ductility product is a good indicator of the overall performance of the alloy. Calculations show that the strength-ductility product of the tungsten-tantalum-nickel-iron-copper alloy in this patent is only 18.821 GPa%, which is lower than that of the traditional 90W-Ni-Fe alloy (~27 GPa%). Summary of the Invention

[0006] To address the problem that the large size of the NiTa phase-strengthened tungsten-tantalum-nickel-iron-copper alloy leads to decreased toughness and a low strength-ductility product, this invention provides a heat treatment method for tungsten-tantalum-nickel-iron-copper alloys. This method can effectively refine the NiTa phase, enabling the alloy to maintain high strength while significantly improving toughness and substantially increasing the strength-ductility product.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] This invention discloses a heat treatment method for a tungsten-tantalum-nickel-iron-copper alloy. The sintered body of the tungsten-tantalum-nickel-iron-copper alloy is first subjected to high-temperature heat treatment at 1100-1250℃, followed by oil quenching immediately after the high-temperature heat treatment, and then subjected to low-temperature heat treatment at 400-500℃. After the low-temperature heat treatment, it is immediately subjected to water quenching to obtain the final product.

[0009] The tungsten-tantalum-nickel-iron-copper alloy sintered body in this invention is obtained using the preparation method described in 202211020238.1. Because the NiTa phase in the tungsten-tantalum-nickel-iron-copper alloy sintered body has a large size, resulting in a low strength-ductility product, this invention first subjects the tungsten-tantalum-nickel-iron-copper alloy sintered body to high-temperature heat treatment at 1100-1250℃, allowing the NiTa reinforcing phase to redissolve in the alloy binder phase through solid-state diffusion reaction at 1100-1250℃, existing as a supersaturated solid solution. Then, it is immediately oil-quenched; the rapid cooling rate suppresses the NiTa phase. The precipitation of the NiTa strengthening phase shortens the time for the merging and growth of the NiTa strengthening phase, thereby refining the NiTa strengthening phase. Then, the tungsten-tantalum-nickel-iron-copper alloy is subjected to low-temperature heat treatment at 400-500℃. At this temperature, copper will redissolve into the binder phase to form the γ-(Ni,Fe,Cu) phase. Then, water quenching is performed immediately. Water quenching inhibits the precipitation of Cu in the binder phase, so that the binder phase maintains a stable γ-(Ni,Fe,Cu) solid solution phase structure at room temperature. At this time, the solid solution strengthening effect of Cu on the binder phase reaches the optimal level.

[0010] In the alloy published in 202211020238.1, the binder phase is γ-(Ni,Fe)-Cu. x The Cu clusters in the binder phase redissolve after high-temperature heating (1100-1250℃) and form a stable γ-(Ni,Fe,Cu) solid solution phase. However, due to the high cooling rate of water quenching, the alloy exhibits microstructure differences due to the large cooling gradient, and also generates significant thermal stress at the two-phase interface, leading to a decrease in alloy performance. Therefore, the alloy of this invention employs oil quenching, a mild heat treatment method, at the high-temperature stage, effectively solving the above problems and achieving the goal of refining the NiTa strengthening phase. However, the slow cooling rate of oil quenching causes Cu in the γ-(Ni,Fe,Cu) solid solution to reprecipitate, and the binder phase reverts to γ-(Ni,Fe)-Cu. x In a clustered configuration, the properties of the binder phase decrease. Therefore, this invention reheats the alloy to a low-temperature state (400-500℃) to allow the γ-(Ni,Fe)-Cu to aggregate. x Cu in the clusters redissolves to form a γ-(Ni,Fe,Cu) solid solution. Subsequent water quenching not only avoids significant thermal stress in the alloy, but the rapid cooling rate also suppresses Cu precipitation, allowing the binder phase to maintain its γ-(Ni,Fe,Cu) solid solution phase structure at room temperature.

[0011] Through the heat treatment of this invention, not only is the NiTa reinforcing phase in the matrix refined, but the binder phase also maintains a γ-(Ni,Fe,Cu) solid solution phase structure at room temperature. At the same time, the binder phase and the matrix phase are in good coherent relationship. The tungsten-tantalum-nickel-iron-copper alloy after the heat treatment of this invention has significantly improved strength and toughness. The ultimate tensile strength of the alloy increases from 1.10 GPa to 1.23 GPa, the average elongation increases from 17.11% to 31.83%, and the strength-ductility product increases from 18.821 GPa% to 39.151 GPa.

[0012] In this invention, the temperatures of high-temperature heat treatment and low-temperature heat treatment need to be effectively controlled. During high-temperature heat treatment, if the temperature is below 1100℃, the NiTa strengthening phase mainly undergoes merging and growth, which is detrimental to the improvement of alloy performance. When the temperature is above 1250℃, due to the liquidus temperature of the nickel-iron-copper binder phase being 1350℃, local component segregation and thermal field fluctuations will lead to the appearance of a liquid phase in the alloy. The appearance of the liquid phase will damage the equipment and mold, and will also further aggravate the component segregation of the alloy. During low-temperature heat treatment, when the temperature is below 400℃, copper cannot be redissolved. When the temperature is above 500℃, secondary oxidation of tantalum is easily caused.

[0013] In a preferred embodiment, the temperature of the high-temperature heat treatment is 1100-1200℃.

[0014] In a preferred embodiment, the high-temperature heat treatment time is 1-5 hours, preferably 1-3 hours. The inventors have discovered that heating for 1-3 hours allows the sample to be fully heated. Heating times shorter than 1 hour are not conducive to sufficient heating of the sample core, and excessively long holding times can lead to coarse sample grains.

[0015] In a preferred embodiment, the high-temperature heat treatment process involves placing the sintered tungsten-tantalum-nickel-iron-copper alloy body in a vacuum quenching furnace, drawing a vacuum to ensure the vacuum degree of the furnace is <5×10⁻⁶. -3 Heating begins at a pressure of Pa, then the temperature is increased to 1100-1250℃ at a rate of 5-10℃ / min, preferably 5℃ / min, and held for 1-3 hours. During the heating and holding periods, the vacuum level is controlled to be <1×10⁻⁶. - 2 Pa.

[0016] In this invention, since tantalum in the tungsten-tantalum-nickel-iron-copper alloy readily reacts with oxygen at temperatures above 500°C to form Ta₂O₅, this invention addresses the issue of the vacuum degree of the vacuum quenching furnace being <5×10⁻⁶. -3 When Pa, heating begins again while simultaneously controlling the vacuum level inside the furnace to <1×10 during the heating and holding process. -2 Pa can effectively prevent oxidation.

[0017] During the heating process, the present invention controls the heating rate to 5-10℃ / min, which can ensure that the thermal field inside the furnace is unstable and that the sintered tungsten-tantalum-nickel-iron-copper alloy is heated evenly.

[0018] In a preferred embodiment, the oil quenching is performed under a protective atmosphere.

[0019] In a further preferred embodiment, the protective atmosphere is argon.

[0020] In actual operation, after the high-temperature heat treatment and heat preservation are completed, the sample is quickly moved to the cooling chamber and high-purity argon gas is introduced to balance the atmospheric pressure. Then it is immediately sent to the quenching oil tank for cooling. After the sample is cooled to room temperature (25℃), the sample is taken out and the surface oil is wiped dry.

[0021] Vacuum quenching furnaces should be cooled using high-purity argon gas.

[0022] In this invention, the quenching oil shall meet the SH / T0564-93 standard.

[0023] The inventors discovered that after high-temperature heat treatment, oil quenching is the optimal cooling method. Water quenching can cause excessive internal thermal stress in the alloy, leading to cracking of tungsten particles and the binder phase under interfacial thermal stress, and in severe cases, even cracking of the tungsten particles. Air cooling is too slow, and the sample core is difficult to cool completely, causing the strengthening phase to precipitate again in large quantities and merge and grow, resulting in a decrease in alloy properties.

[0024] In a preferred embodiment, the temperature of the low-temperature heat treatment is 400-450℃.

[0025] In a preferred embodiment, the low-temperature heat treatment time is 1-4 hours.

[0026] The inventors discovered that heating for 1-4 hours can fully heat the sample. Heating time less than 1 hour is not conducive to sufficient heating of the sample core, but excessive heating time (>4 hours) will waste energy and cause oxidation of the sample surface.

[0027] In a preferred embodiment, the low-temperature heat treatment process involves placing the sintered tungsten-tantalum-nickel-iron-copper alloy body in a vacuum quenching furnace, drawing a vacuum to ensure the vacuum degree of the furnace is <5×10⁻⁶. -3 Start heating at Pa, then raise the temperature to 400-500°C at a rate of 5-10°C / min, preferably 5°C / min, and hold for 1-4 hours.

[0028] During the heating process, the present invention controls the heating rate to 5-10℃ / min, which can ensure that the thermal field inside the furnace is unstable and that the sintered tungsten-tantalum-nickel-iron-copper alloy is heated evenly.

[0029] In a preferred embodiment, the water quenching is performed under a protective atmosphere, and the water used for water quenching is deionized water.

[0030] In a further preferred embodiment, the protective atmosphere is argon.

[0031] This invention involves reheating the alloy to a low-temperature state to obtain γ-(Ni,Fe)-Cu. x Cu in the clusters redissolves to form a γ-(Ni,Fe,Cu) solid solution. Subsequent water quenching not only avoids significant thermal stress in the alloy, but the rapid cooling rate also suppresses Cu precipitation, allowing the binder phase to maintain its γ-(Ni,Fe,Cu) solid solution phase structure at room temperature.

[0032] In actual operation, after the low-temperature heat treatment and holding period, the sample is quickly moved to the cooling chamber, high-purity argon gas is introduced until the pressure equalizes with atmospheric pressure, and then immediately placed in a water bath for cooling. Once the sample has cooled to room temperature (25°C), it is removed and dried. The water bath should contain deionized water, as using deionized water can prevent contamination of the sample by impurity ions.

[0033] Beneficial effects

[0034] The heat treatment method of this invention involves a high-temperature heating process followed by an oil quenching process, a low-temperature heating process, and a water quenching process. First, the sintered tungsten-tantalum-nickel-iron-copper alloy is subjected to high-temperature heat treatment at 1100-1250℃, allowing the NiTa strengthening phase to redissolve in the alloy binder phase via solid-state diffusion at 1100-1250℃, existing as a supersaturated solid solution. Then, immediate oil quenching is performed; the rapid cooling rate inhibits the precipitation of the NiTa strengthening phase and shortens the time for its coalescence and growth, thereby refining the NiTa strengthening phase. Next, the tungsten-tantalum-nickel-iron-copper alloy is subjected to low-temperature heat treatment at 400-500℃, at which temperature copper redissolves in the binder phase, forming a γ-(Ni,Fe,Cu) phase. Immediately afterward, water quenching inhibits the precipitation of Cu in the binder phase, allowing the binder phase to maintain a stable γ-(Ni,Fe,Cu) solid solution phase structure at room temperature. At this point, the solid solution strengthening effect of Cu on the binder phase is optimal.

[0035] The heat treatment method of this invention can refine the average size of the NiTa strengthening phase from ~200 nm to 20-40 nm, increase the ultimate tensile strength of the alloy from 1.10 GPa to 1.23 GPa, increase the average elongation from 17.11% to 31.83%, and increase the strength-ductility product from 18.821 GPa% to 39.151 GPa. Attached Figure Description

[0036] Figure 1 This is a process flow diagram of the present invention.

[0037] Figure 2 The microstructure of the alloy obtained using the method in Example 1 shows that no obvious NiTa reinforcing phase was observed in the binder phase.

[0038] Figure 3 The morphology of the alloy obtained using the method of Example 1 is shown. Figure 3 (a) is a bright-field image of the binder phase; Figure 3 (b) is a dark-field image of the binder phase; Figure 3 (c) is the low-magnification morphology of the high-angle annular dark field image of the binder phase; Figure 3 (d) shows the selected area electron diffraction results of the binder phase and the reinforcing phase in the matrix. It can be seen that the size of the NiTa reinforcing phase is ~20 nm, and this finer reinforcing phase provides excellent strength support for the alloy. Meanwhile, the binder phase and the matrix phase maintain a good coherent relationship, significantly improving the toughness of the alloy.

[0039] Figure 4 The microstructure of the alloy obtained using the method of Example 2 is shown. Its characteristics are similar to those of Example 1.

[0040] Figure 5 The microstructure of the alloy obtained using the method in Comparative Example 1 is shown. It can be seen that the reinforcing phases have merged and grown, transforming from nanoscale reinforcing phases to microscale reinforcing phases, which negatively impacts the alloy's toughness.

[0041] Figure 6 The microstructure of the alloy obtained using the method in Comparative Example 2 is shown. The reinforcing phases grow further but fail to dissolve in the binder phase. At this point, these reinforcing phases are interconnected and penetrate the binder phase, causing a significant decrease in the toughness of the binder phase. Detailed Implementation

[0042] The composition and preparation method of the tungsten-tantalum-nickel-iron-copper alloy used in this method are as described in Example 1 of 202211020238.1, "A High-Strength Ultrafine-Grained Tungsten-tantalum-nickel-iron-copper Alloy, Its Preparation Method and Application".

[0043] The quenching oil used in this invention is quenching oil provided by Shanghai Kunyue Lubrication Technology Co., Ltd., and the standard is SH / T0564-93.

[0044] Example 1

[0045] Step 1: High-temperature heating process.

[0046] The alloy sample was placed in a vacuum quenching furnace, and the vacuum inside the furnace was reduced to 5 × 10⁻⁶. -3 Heating begins at Pa. The temperature is increased to 1200℃ at a rate of 5℃ / min and held for 1 hour.

[0047] Step 2: Sample oil quenching process.

[0048] After the heat preservation is completed, the sample is quickly moved to the cooling chamber and high-purity argon gas is introduced to equalize the atmospheric pressure. Then, it is immediately sent to the quenching oil bath for cooling. After the sample cools to room temperature (25°C), the sample is taken out and the surface oil is wiped dry.

[0049] Step 3: Low-temperature heating process.

[0050] The alloy sample was placed back into the vacuum quenching furnace, and the vacuum inside the furnace was reduced to 5 × 10⁻⁶. -3 Heating begins at Pa. The temperature is increased to 450°C at a rate of 5°C / min and held for 1 hour.

[0051] Step 4: Sample water quenching process.

[0052] After the heat preservation is completed, the sample is quickly moved to the cooling chamber, high-purity argon gas is introduced to equalize the atmospheric pressure, and then immediately sent to the water tank (containing deionized water) for cooling. After the sample cools to room temperature (25°C), the sample is taken out and wiped dry.

[0053] Figure 2 The microstructure of the alloy obtained using the method in Example 1 shows that no obvious NiTa reinforcing phase was observed in the binder phase.

[0054] Figure 3 The morphology of the alloy obtained using the method of Example 1 is shown. Figure 3 (a) is a bright-field image of the binder phase; Figure 3 (b) is a dark-field image of the binder phase; Figure 3 (c) is the low-magnification morphology of the high-angle annular dark field image of the binder phase; Figure 3 (d) shows the selected area electron diffraction results of the binder phase and the reinforcing phase in the matrix. It can be seen that the size of the NiTa reinforcing phase is ~20 nm, and this finer reinforcing phase provides excellent strength support for the alloy. Meanwhile, the binder phase and the matrix phase maintain a good coherent relationship, significantly improving the toughness of the alloy.

[0055] The performance results of the tungsten-tantalum-nickel-iron-copper alloy obtained in Example 1 are shown in Table 1.

[0056] Example 2

[0057] Step 1: High-temperature heating process.

[0058] The alloy sample was placed in a vacuum quenching furnace, and the vacuum inside the furnace was reduced to 5 × 10⁻⁶. -3 Heating begins at Pa. The temperature is increased to 1100℃ at a rate of 5℃ / min and held for 2 hours.

[0059] Step 2: Sample oil quenching process.

[0060] After the heat preservation is completed, the sample is quickly moved to the cooling chamber and high-purity argon gas is introduced to equalize the atmospheric pressure. Then, it is immediately sent to the quenching oil bath for cooling. After the sample cools to room temperature (25°C), the sample is taken out and the surface oil is wiped dry.

[0061] Step 3: Low-temperature heating process.

[0062] The alloy sample was placed back into the vacuum quenching furnace, and the vacuum inside the furnace was reduced to 5 × 10⁻⁶. -3 Heating begins at Pa. The temperature is increased to 450°C at a rate of 5°C / min and held for 2 hours.

[0063] Step 4: Sample water quenching process.

[0064] After the heat preservation is completed, the sample is quickly moved to the cooling chamber, high-purity argon gas is introduced to equalize the atmospheric pressure, and then it is immediately sent to the water bath for cooling. After the sample is cooled to room temperature (25°C), the sample is taken out and wiped dry.

[0065] Figure 4 The microstructure of the tungsten-tantalum-nickel-iron-copper alloy obtained using the method of Example 2 is shown. Its characteristics are similar to those of Example 1.

[0066] The performance results of the tungsten-tantalum-nickel-iron-copper alloy obtained in Example 2 are shown in Table 1.

[0067] Example 3

[0068] Step 1: High-temperature heating process.

[0069] The alloy sample was placed in a vacuum quenching furnace, and the vacuum inside the furnace was reduced to 5 × 10⁻⁶. -3 Heating begins at Pa. The temperature is increased to 1250℃ at a rate of 5℃ / min and held for 3 hours.

[0070] Step 2: Sample oil quenching process.

[0071] After the heat preservation is completed, the sample is quickly moved to the cooling chamber and high-purity argon gas is introduced to equalize the atmospheric pressure. Then, it is immediately sent to the quenching oil bath for cooling. After the sample cools to room temperature (25°C), the sample is taken out and the surface oil is wiped dry.

[0072] Step 3: Low-temperature heating process.

[0073] The alloy sample was placed back into the vacuum quenching furnace, and the vacuum inside the furnace was reduced to 5 × 10⁻⁶. -3 Heating begins at Pa. The temperature is increased to 500℃ at a rate of 5℃ / min and held for 4 hours.

[0074] Step 4: Sample water quenching process.

[0075] After the heat preservation is completed, the sample is quickly moved to the cooling chamber, high-purity argon gas is introduced to equalize the atmospheric pressure, and then it is immediately sent to the water bath for cooling. After the sample is cooled to room temperature (25°C), the sample is taken out and wiped dry.

[0076] The performance results of the tungsten-tantalum-nickel-iron-copper alloy obtained in Example 3 are shown in Table 1.

[0077] Example 4

[0078] Step 1: High-temperature heating process.

[0079] The alloy sample was placed in a vacuum quenching furnace, and the vacuum inside the furnace was reduced to 5 × 10⁻⁶. -3 Start heating at Pa. Increase the temperature to 1200℃ at a rate of 5-10℃ / min and hold for 2 hours.

[0080] Step 2: Sample oil quenching process.

[0081] After the heat preservation is completed, the sample is quickly moved to the cooling chamber and high-purity argon gas is introduced to equalize the atmospheric pressure. Then, it is immediately sent to the quenching oil bath for cooling. After the sample cools to room temperature (25°C), the sample is taken out and the surface oil is wiped dry.

[0082] Step 3: Low-temperature heating process.

[0083] The alloy sample was placed back into the vacuum quenching furnace, and the vacuum inside the furnace was reduced to 5 × 10⁻⁶. -3 Heating begins at Pa. The temperature is increased to 400℃ at a rate of 5℃ / min and held for 2 hours.

[0084] Step 4: Sample water quenching process.

[0085] After the heat preservation is completed, the sample is quickly moved to the cooling chamber, high-purity argon gas is introduced to equalize the atmospheric pressure, and then it is immediately sent to the water bath for cooling. After the sample is cooled to room temperature (25°C), the sample is taken out and wiped dry.

[0086] The performance results of the tungsten-tantalum-nickel-iron-copper alloy obtained in Example 4 are shown in Table 1.

[0087] Example 5

[0088] The difference from Example 1 is that:

[0089] Step 1: High-temperature heating process.

[0090] The alloy sample was placed in a vacuum quenching furnace, and the vacuum inside the furnace was reduced to 5 × 10⁻⁶. -3 Heating begins at Pa. The temperature is increased to 1200℃ at a rate of 5℃ / min and held for 5 hours.

[0091] All other operations are the same.

[0092] The performance results of the tungsten-tantalum-nickel-iron-copper alloy obtained in Example 5 are shown in Table 1.

[0093] Comparative Example 1

[0094] The difference from Example 1 is that:

[0095] Step 1: High-temperature heating process.

[0096] The alloy sample was placed in a vacuum quenching furnace, and the vacuum inside the furnace was reduced to 5 × 10⁻⁶. -3 Heating begins at Pa. The temperature is increased to 900℃ at a rate of 5℃ / min and held for 1 hour.

[0097] All other operations are the same.

[0098] Figure 5 The microstructure of the tungsten-tantalum-nickel-iron-copper alloy obtained using the method in Comparative Example 1 is shown. It can be seen that the reinforcing phases have merged and grown, transforming from nanoscale reinforcing phases to microscale reinforcing phases, which negatively impacts the alloy's toughness.

[0099] The performance results of the tungsten-tantalum-nickel-iron-copper alloy obtained in Comparative Example 1 are shown in Table 1.

[0100] Comparative Example 2

[0101] The difference from Example 1 is that:

[0102] Step 1: High-temperature heating process.

[0103] The alloy sample was placed in a vacuum quenching furnace, and the vacuum inside the furnace was reduced to 5 × 10⁻⁶. -3 Heating begins at Pa. The temperature is increased to 1000℃ at a rate of 5℃ / min and held for 1 hour.

[0104] All other operations are the same.

[0105] Figure 6 The microstructure of the alloy obtained using the method in Comparative Example 2 is shown. The reinforcing phases grow further but fail to dissolve in the binder phase. At this point, these reinforcing phases are interconnected and penetrate the binder phase, causing a significant decrease in the toughness of the binder phase.

[0106] The performance results of the tungsten-tantalum-nickel-iron-copper alloy obtained in Comparative Example 2 are shown in Table 1.

[0107] Comparative Example 3

[0108] The difference from Example 1 is that steps three and four are omitted, and mechanical property testing is performed directly after oil quenching. The performance results of the tungsten-tantalum-nickel-iron-copper alloy obtained in Comparative Example 3 are shown in Table 1.

[0109] Table 1. Performance test results of samples from Examples 1-5 and Comparative Examples 1-3

[0110] Sample number Ultimate tensile strength / GPa Average elongation / % High Plasticity / GPa% Example 1 1.23 31.83 39.151 Example 2 1.21 31.02 37.534 Example 3 1.18 30.80 36.344 Example 4 1.20 31.34 37.608 Example 5 1.22 30.11 36.734 Comparative Example 1 1.19 26.22 31.202 Comparative Example 2 1.19 25.37 30.190 Comparative Example 3 1.18 27.46 32.403

[0111] After treatment using this method, the ultimate tensile strength of the alloy increased from 1.10 GPa to 1.23 GPa, the average elongation increased from 17.11% to 31.83%, and the strength-ductility product increased from 18.821 GPa% to 39.151 GPa.

Claims

1. A heat treatment method for a tungsten-tantalum-nickel-iron-copper alloy, characterized in that: The sintered tungsten-tantalum-nickel-iron-copper alloy body is first subjected to high-temperature heat treatment at 1100-1250℃, and then immediately after the high-temperature heat treatment is performed by oil quenching. After that, it is subjected to low-temperature heat treatment at 400-500℃, and then immediately after the low-temperature heat treatment is performed by water quenching.

2. The heat treatment method for a tungsten-tantalum-nickel-iron-copper alloy according to claim 1, characterized in that: The high-temperature heat treatment temperature is 1100-1200℃.

3. The heat treatment method for a tungsten-tantalum-nickel-iron-copper alloy according to claim 1, characterized in that: The high-temperature heat treatment time is 1-5 hours.

4. The heat treatment method for a tungsten-tantalum-nickel-iron-copper alloy according to claim 1, characterized in that: The high-temperature heat treatment process is as follows: the sintered tungsten-tantalum-nickel-iron-copper alloy is placed in a vacuum quenching furnace, and a vacuum is drawn to ensure that the vacuum degree of the vacuum quenching furnace is <5×10⁻⁶. -3 Start heating at a pressure of Pa, then increase the temperature to 1100-1250℃ at a rate of 5-10℃ / min, and hold at that temperature for 1-3 hours. Maintain a vacuum level <1×10⁻⁶ during both heating and holding periods. -2 Pa.

5. A heat treatment method for a tungsten-tantalum-nickel-iron-copper alloy according to any one of claims 1-3, characterized in that: The oil quenching is performed under a protective atmosphere.

6. The heat treatment method for a tungsten-tantalum-nickel-iron-copper alloy according to claim 1, characterized in that: The temperature of the low-temperature heat treatment is 400-450℃.

7. The heat treatment method for a tungsten-tantalum-nickel-iron-copper alloy according to claim 1, characterized in that: The low-temperature heat treatment lasts for 1-4 hours.

8. The heat treatment method for a tungsten-tantalum-nickel-iron-copper alloy according to claim 1, characterized in that: The low-temperature heat treatment process is as follows: the sintered tungsten-tantalum-nickel-iron-copper alloy is placed in a vacuum quenching furnace, and a vacuum is drawn to ensure that the vacuum degree of the vacuum quenching furnace is <5×10⁻⁶. -3 Start heating at Pa, then increase the temperature to 400-500℃ at a rate of 5-10℃ / min, and hold for 1-4 hours.

9. A heat treatment method for a tungsten-tantalum-nickel-iron-copper alloy according to any one of claims 1, 6, and 7, characterized in that: The water quenching is carried out under a protective atmosphere, and the water used for water quenching is deionized water.

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