CN114888291B

CN114888291B - Method for improving plasticity of powder metallurgy high tungsten tantalum alloy

Info

Publication number: CN114888291B
Application number: CN202210558253.5A
Authority: CN
Inventors: 王晖; 林小辉; 梁静; 李延超; 王峰
Original assignee: Northwest Institute for Non Ferrous Metal Research
Current assignee: Northwest Institute for Non Ferrous Metal Research
Priority date: 2022-05-20
Filing date: 2022-05-20
Publication date: 2023-05-26
Anticipated expiration: 2042-05-20
Also published as: CN114888291A

Abstract

The invention discloses a method for improving plasticity of a powder metallurgy high tungsten tantalum alloy, which adopts a process of combining sponge zirconium adsorption and high-temperature vacuum heat treatment at high temperature to treat a high tungsten tantalum alloy product after hot isostatic pressing in the preparation process of the powder metallurgy high tungsten tantalum alloy. According to the invention, a two-step heat treatment method is adopted, firstly, the sponge zirconium deoxidizer is adopted to adsorb oxygen in the high-tungsten tantalum alloy product, then, the high-temperature vacuum heat treatment is adopted to promote the volatilization of oxygen and oxides in the high-tungsten tantalum alloy product, so that the diffusion and escape of solid solution oxygen in a crystal boundary are promoted, the oxygen content is effectively reduced, the crystal boundary is purified, the binding force of the crystal boundary is improved, the internal stress generated by hot isostatic pressing is released, and the plasticity of the alloy is greatly improved while the strength of the high-tungsten tantalum alloy is ensured.

Description

Method for improving plasticity of powder metallurgy high tungsten tantalum alloy

Technical Field

The invention belongs to the technical field of refractory metal alloy high-temperature structure and functional material preparation, and particularly relates to a method for improving the plasticity of a powder metallurgy high-tungsten tantalum alloy.

Background

The tungsten-tantalum alloy is a very important material with wide application range and excellent high-temperature resistance, impact resistance and dynamic mechanical properties, and particularly the high-tungsten-tantalum alloy is mostly used in extremely harsh working condition environments. The high-tungsten tantalum alloy has higher creep strength and low creep rate, so the tantalum tungsten alloy is a better candidate material for the heat-resistant scouring component, and has the characteristics of high density, high melting point, good corrosion resistance, good processability, weldability and the like, and is gradually applied to the fields of weapons, aerospace and the like in recent years. At present, the mature high tungsten tantalum alloy applied in China mainly comprises TaW10 and TaW12. As refractory metal alloy, tungsten-tantalum alloy has the characteristic of easy oxidation at high temperature and is generally prepared by adopting a vacuum electron beam smelting method. The tungsten tantalum cast ingot smelted by the electron beam has low impurity and interstitial element content, uniform components and good plasticity, and the oxygen content is easily controlled below 0.01%; and the elongation percentage of the alloy TaW10 and TaW12 melted by the electron beam after pressure processing can reach 20-40%. The high tungsten tantalum alloy is high in strength and easy to oxidize, so that pressure processing and forming are difficult, and although the conventional plate and bar production process is mature at present, the conventional plate and bar production process is limited by the size of an electron beam smelting cast ingot, and some large-size alloy components, special-shaped parts, thin (thick) wall cylindrical parts and the like are difficult to realize by adopting a mode of combining electron beam smelting with pressure processing, so that the products and the components can only be prepared by adopting a powder metallurgy method.

Hot isostatic pressing (Hot isostatic pressing, HIP) is a technique in which isostatic pressure is applied to a powder metallurgical product or compact by high-pressure gas at high temperature, internal defects and voids of the product are eliminated, and at the same time, diffusion bonding is performed at the grain boundaries at high temperature, so that the mechanical properties of the product are improved, and complete densification is achieved. In recent years, hot isostatic pressing technology has been increasingly applied to refractory alloy processing. The method comprises the steps of filling alloy powder which is uniformly mixed into a preformed sheath, pressing to obtain a blank with the density close to the theoretical density, and then obtaining a required product through simple machining. The method has short flow, easy control, high yield and is very suitable for preparing special-shaped pieces.

The most common preparation method of the raw material powder adopted by the powder metallurgy high tungsten tantalum alloy product is to prepare the alloy ingot hydrogenation dehydrogenation or plasma rotating electrode with vacuum melting components meeting national standards. The alloy ingot hydrogenation powder preparation has the advantages that Ta and W elements are alloyed, the powder preparation process only changes physical shapes, powder particles are still alloy, and element segregation is avoided. However, even when an ingot having an extremely low O content (0.01% or less) is used, it is difficult to avoid a large increase in the oxygen content of the powder (generally more than 0.06%) due to the long-time high-temperature hydrogenation, dehydrogenation and mechanical crushing. Compared with the powder prepared by hydrogenation and dehydrogenation, the powder prepared by the rotary electrode powder preparation has lower oxygen content, but because the method adopts argon protection, unavoidable oxygen elements (about 0.1 percent) in the argon can be adsorbed by the powder, and certain oxygenation can still be realized. In the hot isostatic pressing forming process, the high-oxygen-content powder can not remove oxygen due to complete sealing of the sheath, and finally is completely enriched at the grain boundary, so that the plasticity of the product is drastically reduced, the post-machine forming is affected, and the mechanical property and the reliability of the alloy product are greatly affected.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a method for improving the plasticity of the powder metallurgy high tungsten tantalum alloy aiming at the defects in the prior art. According to the method, for the high-tungsten tantalum alloy product subjected to hot isostatic pressing, the sponge zirconium deoxidizer is firstly adopted to adsorb oxygen in the high-tungsten tantalum alloy product, and then high-temperature vacuum heat treatment is adopted to promote volatilization of oxygen and oxides in the high-tungsten tantalum alloy product, so that the oxygen content is effectively reduced, the binding force of a grain boundary is improved, the strength of the high-tungsten tantalum alloy is ensured, and meanwhile, the plasticity of the alloy is greatly improved.

In order to solve the technical problems, the invention adopts the following technical scheme: a method for improving plasticity of powder metallurgy high tungsten tantalum alloy is characterized in that the method adopts a process of combining sponge zirconium adsorption and high-temperature vacuum heat treatment at high temperature to treat a high tungsten tantalum alloy product after hot isostatic pressing in the preparation process of the powder metallurgy high tungsten tantalum alloy; the high tungsten tantalum alloy product comprises a TaW10 alloy or a TaW12 alloy.

According to the invention, for the high-tungsten tantalum alloy product subjected to hot isostatic pressing in the preparation process of the powder metallurgy high-tungsten tantalum alloy, by adopting a two-step heat treatment method, firstly, sponge zirconium is adopted as a deoxidizer to adsorb oxygen in the high-tungsten tantalum alloy product, and then, high-temperature vacuum heat treatment is adopted, so that the volatilization of solid solution oxygen and residual oxide in the high-tungsten tantalum alloy product is further promoted, the oxygen content in the high-tungsten tantalum alloy product is effectively reduced, the grain boundary is purified, the high-temperature sintering effect is combined, and the grain boundary binding force is improved, thereby greatly improving the plasticity of the alloy, and solving the problem that the plasticity of the high-tungsten tantalum alloy product is sharply reduced due to oxygen enrichment at the grain boundary in the hot isostatic pressing process.

The method for improving the plasticity of the powder metallurgy high tungsten tantalum alloy is characterized by comprising the following specific processes of: removing a titanium sheath or a niobium sheath from a high tungsten tantalum alloy product subjected to hot isostatic pressing by machining, then placing the high tungsten tantalum alloy product into a crucible, filling with sponge zirconium, integrally placing the crucible into a vacuum furnace for one-time heat treatment, taking out the sponge zirconium after the furnace temperature is reduced to room temperature, and placing the high tungsten tantalum alloy product and the crucible into the vacuum furnace for feedingCarrying out secondary heat treatment, cooling and discharging; the system of the primary heat treatment is as follows: preserving heat for 1-3 h at 1300-1450 ℃, and keeping the vacuum degree at 5.0x10 in the heating, preserving heat and cooling process of one-time heat treatment ^-1 ～5×10 ^-3 Pa; the secondary heat treatment system is as follows: preserving heat for 2-4 h at 2160-2200 ℃, and keeping vacuum degree at 5.0X10 in the heating, preserving heat and cooling process of the secondary heat treatment ^-2 ～5×10 ^-4 Pa。

Oxygen absorption of tantalum and tantalum alloy starts at 400 ℃ or higher, and even if the oxygen content is increased in vacuum heat treatment, oxygen has a solid solution strengthening effect in tantalum and tantalum alloy, so that the hardness is increased by 1-3 times, but the plasticity of tantalum and tantalum alloy is greatly reduced, and therefore, the solid solution of oxygen in tantalum and tantalum alloy is used as a harmful element which damages the plasticity and toughness and needs to be reduced or removed as much as possible. For this case, the present invention creatively uses a two-step heat treatment process: firstly, placing the hot isostatic pressing high tungsten tantalum alloy product with the sheath removed in a crucible, adopting sponge zirconium landfill to perform primary heat treatment in a vacuum state, limiting the temperature of the primary heat treatment to 1300-1450 ℃, and utilizing the characteristic that oxygen has lower diffusion rate in the high tungsten tantalum alloy product at the temperature to volatilize the oxide of tantalum in the high tungsten tantalum alloy product and have strong adsorption action with surrounding sponge zirconium landfill, so that the oxygen in the high tungsten tantalum alloy product is primarily and effectively removed, and meanwhile, avoiding the melting failure of the sponge zirconium caused by overhigh temperature; and then taking out the zirconium sponge, continuing to perform secondary heat treatment at a vacuum state higher than 2100 ℃, limiting the temperature of the secondary heat treatment to 2160-2200 ℃, and since the low-valence oxide formed by tantalum and oxygen in the high-tungsten tantalum alloy product is adsorbed and volatilized in the primary heat treatment process, the residual solid dissolved oxygen begins to diffuse outwards and escape at a high temperature higher than 2100 ℃, the crystal boundary of the alloy in the high-tungsten tantalum alloy product is sufficiently purified, and meanwhile, the secondary heat treatment ensures that the high-tungsten tantalum alloy product forms a compact combined whole through high-temperature sintering, thereby improving the inter-crystal binding force, releasing the internal stress generated by hot isostatic pressing and greatly improving the plasticity of the high-tungsten tantalum alloy.

The method for improving the plasticity of the powder metallurgy high tungsten tantalum alloy is characterized in that the one-time heat treatment system is as follows: preserving heat for 2h at 1350 ℃, and the secondary heat treatment system is as follows: preserving heat for 2h at 2180-2200 ℃.

The method for improving the plasticity of the powder metallurgy high tungsten tantalum alloy is characterized in that the heating rates of the primary heat treatment and the secondary heat treatment are 5 ℃/min-17 ℃/min. The invention ensures the smooth temperature rise of the high tungsten tantalum alloy product by controlling the temperature rise rate of the two heat treatments, thereby fully removing oxygen by the heat treatment and being beneficial to the improvement of the plasticity of the high tungsten tantalum alloy.

The method for improving the plasticity of the powder metallurgy high tungsten tantalum alloy is characterized in that the sponge zirconium is industrial sponge zirconium with the brand number of HZr-01, and the particle size is 3-8 mm. The sponge zirconium has low impurity and gas content, good quality, small particle size and good adsorption effect, and improves the adsorption capacity of the sponge zirconium on volatile oxides in high-tungsten tantalum alloy products. Generally, in order to ensure the adsorption effect of the zirconium sponge on the oxide, the zirconium sponge adopted in the primary heat treatment process is not reusable.

The method for improving the plasticity of the powder metallurgy high tungsten tantalum alloy is characterized in that the degree of filling of the sponge zirconium is that the high tungsten tantalum alloy product is fully filled. According to the invention, the sponge zirconium is used for filling the high-tungsten tantalum alloy product until the sponge zirconium is fully filled and coated, so that the contact area of the sponge zirconium and the high-tungsten tantalum alloy product is increased, the adsorption effect of the sponge zirconium on oxygen is improved, and the full removal of oxygen in the high-tungsten tantalum alloy product is facilitated.

The method for improving the plasticity of the powder metallurgy high tungsten tantalum alloy is characterized in that the vacuum furnace is a high-temperature vacuum annealing furnace, a tungsten wire mesh is adopted as a heating body, and a molybdenum plate, a tantalum plate or a tungsten plate is adopted as a crucible and a heat shield. The vacuum furnace composed of the material structure is suitable for the heat treatment process with the temperature of more than 2000 ℃.

The room temperature in the invention is 25-35 ℃.

Compared with the prior art, the invention has the following advantages:

1. the invention adopts a two-step heat treatment method, firstly adopts the sponge zirconium deoxidizer to adsorb oxygen in the high-tungsten tantalum alloy product, and then adopts high-temperature vacuum heat treatment to promote the volatilization of oxygen and oxide in the high-tungsten tantalum alloy product, thereby effectively reducing the oxygen content, improving the binding force of grain boundaries, and greatly improving the plasticity of the alloy while ensuring the strength of the high-tungsten tantalum alloy.

2. Compared with the method for heating and deoxidizing by using a vacuum furnace, the method creatively adopts the zirconium sponge as the vacuum adsorbent in the furnace, obviously improves the deoxidizing effect, and has simple process and easy implementation.

3. According to the method, the temperature of the heat treatment is precisely controlled for two times, and the oxide and solid solution oxygen of tantalum in the high-tungsten tantalum alloy product are sequentially and step by step removed, so that the crystal boundary is purified, the metallurgical bonding is formed by high-temperature sintering, the inter-crystal bonding force is improved, the internal stress generated by hot isostatic pressing is released, and the plasticity of the high-tungsten tantalum alloy is greatly improved.

4. The equipment adopted by the invention is the existing common equipment in the industry, special equipment is not needed, the equipment requirement is not high, the condition control process is simple, and the implementation is easy.

The technical scheme of the invention is further described in detail through the drawings and the embodiments.

Drawings

FIG. 1 is a SEM image of tensile fracture of a TaW10 alloy prepared in example 1 of the present invention.

FIG. 2 is a SEM image of tensile fracture of a TaW10 alloy prepared in example 2 of the present invention.

FIG. 3 is a drawing showing a tensile fracture of the TaW12 alloy prepared in example 3 of the present invention.

FIG. 4 is a drawing showing a tensile fracture of the TaW12 alloy prepared in example 4 of the present invention.

Detailed Description

Example 1

The specific process of the embodiment is as follows: the TaW10 alloy product after hot isostatic pressing is machined by a lathe to remove a titanium sheath, and is cleaned by a metal cleaning agent and dried; placing the dried TaW10 alloy product in a tungsten crucible, burying the dried TaW10 alloy product into the tungsten crucible by adopting zirconium sponge with the trademark HZr-01 and the grain diameter of 3-8 mm, putting the whole into a vacuum furnace for primary heat treatment, cooling the product to room temperature along with the furnace, and taking out the zirconium sponge; then placing the TaW10 alloy product and the tungsten crucible into a vacuum furnace for secondary heat treatment, and cooling to below 80 ℃ along with the furnace to obtain the TaW10 alloy;

the system of the primary heat treatment is as follows: at a vacuum degree of 5.0X10 ^-1 ～5×10 ^-3 Under the Pa condition, the temperature is raised from room temperature to 1350 ℃ within 1.5h, and the temperature is kept for 2h, and then the furnace is cooled; the secondary heat treatment system is as follows: at a vacuum degree of 5.0X10 ^-2 ～5×10 ^-4 Under the Pa condition, heating from room temperature to 2180 ℃ within 2.5h, preserving heat for 2h, and cooling along with the furnace;

the vacuum furnace is a high-temperature vacuum annealing furnace, a tungsten wire mesh is adopted as a heating body, and a molybdenum plate, a tantalum plate or a tungsten plate is adopted as a crucible and a heat shield.

The TaW10 alloy product washed and dried with the metal cleaner in this example was sampled as a sample before treatment, and the obtained TaW10 alloy was sampled as a sample after treatment, and room temperature mechanical property test and oxygen content analysis were performed, respectively, wherein the sampling position for room temperature mechanical property test was the upper end face, the sampling position for oxygen content analysis was the middle upper portion, middle lower portion of the outer circumferential surface, and the results are shown in table 1 below.

TABLE 1

The "/" in Table 1 indicates that the sample is directly brittle and does not have this indicator.

As can be seen from table 1, the oxygen mass content in the TaW10 alloy obtained by the two-step heat treatment in this example is significantly reduced compared with the TaW10 alloy product after hot isostatic pressing, and the strength including tensile strength and yield strength are significantly improved, and both the elongation and the end surface shrinkage are improved, which means that the method of this example improves the strength of the powder metallurgy high tungsten tantalum alloy and also greatly improves the plasticity thereof.

Fig. 1 is an SEM image of a tensile fracture of the TaW10 alloy prepared in this example, and as can be seen from fig. 1, there is no obvious interface between grains of the tensile fracture of the TaW10 alloy, the ductile pit becomes larger and deeper, the sliding phenomenon on the ductile pit is more obvious, and a large number of shrinkage holes appear at the bottom of the ductile pit, which is characterized by plastic deformation.

Example 2

the system of the primary heat treatment is as follows: at a vacuum degree of 5.0X10 ^-1 ～5×10 ^-3 Under the Pa condition, the temperature is raised from room temperature to 1300 ℃ within 4.25h, the temperature is kept for 3h, and then the furnace is cooled; the secondary heat treatment system is as follows: at a vacuum degree of 5.0X10 ^-2 ～5×10 ^-4 Under the Pa condition, the temperature is raised from room temperature to 2200 ℃ within 7.25h, the temperature is kept for 4h, and then the furnace is cooled;

The TaW10 alloy product washed and dried with the metal cleaner in this example was sampled as a sample before treatment, and the obtained TaW10 alloy was sampled as a sample after treatment, and room temperature mechanical property test and oxygen content analysis were performed, respectively, wherein the sampling position for room temperature mechanical property test was the upper end face, the sampling position for oxygen content analysis was the middle upper portion, middle lower portion of the outer circumferential surface, and the results are shown in table 2 below.

TABLE 2

The "/" in Table 2 indicates that the sample is directly brittle and does not have this indicator.

As can be seen from table 2, the oxygen mass content in the TaW10 alloy obtained by the two-step heat treatment in this example is significantly reduced compared with the TaW10 alloy product after hot isostatic pressing, and the strength including tensile strength and yield strength are significantly improved, and both the elongation and the end surface shrinkage are improved, which means that the method of this example improves the strength of the powder metallurgy high tungsten tantalum alloy and also greatly improves the plasticity thereof.

Fig. 2 is an SEM image of a tensile fracture of the TaW10 alloy prepared in this example, and as can be seen from fig. 2, the slippage phenomenon on the ductile pit of the tensile fracture of the TaW10 alloy is obvious, and a large number of shrinkage holes appear at the bottom of the ductile pit, which is typical of plastic deformation.

Example 3

The specific process of the embodiment is as follows: the TaW12 alloy product after hot isostatic pressing is machined by a lathe to remove a titanium sheath, and is cleaned by a metal cleaning agent and dried; placing the dried TaW12 alloy product in a tungsten crucible, burying the dried TaW12 alloy product into the tungsten crucible by adopting zirconium sponge with the trademark HZr-01 and the particle size of 3-8 mm, putting the whole into a vacuum furnace for primary heat treatment, cooling the product to room temperature along with the furnace, and taking out the zirconium sponge; then placing the TaW12 alloy product and the tungsten crucible into a vacuum furnace for secondary heat treatment, and cooling to below 80 ℃ along with the furnace to obtain a TaW12 alloy;

the system of the primary heat treatment is as follows: at a vacuum degree of 5.0X10 ^-1 ～5×10 ^-3 Under the Pa condition, heating from room temperature to 1350 ℃ in 2 hours, preserving heat for 2 hours, and cooling along with the furnace; the secondary heat treatment system is as follows: at a vacuum degree of 5.0X10 ^-2 ～5×10 ^-4 Under the Pa condition, heating from room temperature to 2160 ℃ in 3 hours, preserving heat for 2 hours, and cooling along with the furnace;

The TaW12 alloy product washed and dried with the metal cleaner in this example was sampled as a sample before treatment, and the obtained TaW12 alloy was sampled as a sample after treatment, and room temperature mechanical property test and oxygen content analysis were performed, respectively, wherein the sampling position for room temperature mechanical property test was the upper end face, the sampling position for oxygen content analysis was the middle upper portion, middle lower portion of the outer circumferential surface, and the results are shown in table 3 below.

TABLE 3 Table 3

The "/" in Table 3 indicates that the sample is directly brittle and does not have this indicator.

As can be seen from table 3, the oxygen mass content in the TaW12 alloy obtained by the two-step heat treatment in this example is significantly reduced compared with the TaW12 alloy product after hot isostatic pressing, and the strength including tensile strength and yield strength are significantly improved, and both the elongation and the end surface shrinkage are improved, which means that the method of this example improves the strength of the powder metallurgy high tungsten tantalum alloy and also greatly improves the plasticity thereof.

Fig. 3 is a drawing-fracture physical diagram of the TaW12 alloy prepared in this example, and as can be seen from fig. 3, the TaW12 alloy has an obvious necking phenomenon after being drawn, and shows a better plastic fracture characteristic.

Example 4

the system of the primary heat treatment is as follows: at the position ofVacuum degree of 5.0X10 ^-1 ～5×10 ^-3 Under the Pa condition, the temperature is raised from room temperature to 1300 ℃ within 1.5h, and the temperature is kept for 1h, and then the furnace is cooled; the secondary heat treatment system is as follows: at a vacuum degree of 5.0X10 ^-2 ～5×10 ^-4 Under Pa, the temperature is raised from room temperature to 2180 ℃ within 2.5h, and the temperature is kept for 2h, and then the mixture is cooled along with the furnace.

The TaW12 alloy product washed and dried with the metal cleaner in this example was sampled as a sample before treatment, and the obtained TaW12 alloy was sampled as a sample after treatment, and room temperature mechanical property test and oxygen content analysis were performed, respectively, wherein the sampling position for room temperature mechanical property test was the upper end face, the sampling position for oxygen content analysis was the middle upper portion, middle lower portion of the outer circumferential surface, and the results are shown in table 4 below.

TABLE 4 Table 4

/>

The "/" in Table 4 indicates that the sample is directly brittle and does not have this indicator.

As can be seen from table 4, the oxygen mass content in the TaW12 alloy obtained by the two-step heat treatment in this example is significantly reduced compared with the TaW12 alloy product after hot isostatic pressing, and the strength including tensile strength and yield strength are significantly improved, and both the elongation and the end surface shrinkage are improved, which means that the method of this example improves the strength of the powder metallurgy high tungsten tantalum alloy and also greatly improves the plasticity thereof.

Fig. 4 is a drawing of a tensile fracture of the TaW12 alloy prepared in this example, and as can be seen from fig. 4, the tensile fracture of the TaW12 alloy is dotted, and the shrinkage rate of the end surface is high, and the tensile fracture shows obvious plastic fracture characteristics.

Example 5

the system of the primary heat treatment is as follows: at a vacuum degree of 5.0X10 ^-1 ～5×10 ^-3 Under the Pa condition, heating from room temperature to 1450 ℃ in 1.4h, preserving heat for 1h, and cooling along with the furnace; the secondary heat treatment system is as follows: at a vacuum degree of 5.0X10 ^-2 ～5×10 ^-4 Under the Pa condition, heating from room temperature to 2160 ℃ in 2 hours, preserving heat for 2 hours, and cooling along with the furnace;

The TaW10 alloy product washed and dried with the metal cleaner in this example was sampled as a sample before treatment, and the obtained TaW10 alloy was sampled as a sample after treatment, and room temperature mechanical property test and oxygen content analysis were performed, respectively, wherein the sampling position for room temperature mechanical property test was the upper end face, the sampling position for oxygen content analysis was the middle upper portion, middle lower portion of the outer circumferential surface, and the results are shown in table 5 below.

TABLE 5

The "/" in Table 5 indicates that the sample is directly brittle and does not have this indicator.

As can be seen from table 5, the oxygen mass content in the TaW10 alloy obtained by the two-step heat treatment in this example is significantly reduced compared with the TaW10 alloy product after hot isostatic pressing, and the strength including tensile strength and yield strength are significantly improved, and both the elongation and the end surface shrinkage are improved, which means that the method of this example improves the strength of the powder metallurgy high tungsten tantalum alloy and also greatly improves the plasticity thereof.

Example 6

the system of the primary heat treatment is as follows: at a vacuum degree of 5.0X10 ^-1 ～5×10 ^-3 Under the Pa condition, heating from room temperature to 1450 ℃ in 1.4h, preserving heat for 3h, and cooling along with the furnace; the secondary heat treatment system is as follows: at a vacuum degree of 5.0X10 ^-2 ～5×10 ^-4 Under the Pa condition, heating from room temperature to 2200 ℃ in 2.1h, preserving heat for 4h, and cooling along with the furnace;

The TaW12 alloy product washed and dried with the metal cleaner in this example was sampled as a sample before treatment, and the obtained TaW12 alloy was sampled as a sample after treatment, and room temperature mechanical property test and oxygen content analysis were performed, respectively, wherein the sampling position for room temperature mechanical property test was the upper end face, the sampling position for oxygen content analysis was the middle upper portion, middle lower portion of the outer circumferential surface, and the results are shown in table 6 below.

TABLE 6

The "/" in Table 6 indicates that the sample is directly brittle and does not have this indicator.

As can be seen from table 6, the oxygen mass content in the TaW12 alloy obtained by the two-step heat treatment in this example is significantly reduced compared with the TaW12 alloy product after hot isostatic pressing, and the strength including tensile strength and yield strength are significantly improved, and both the elongation and the end surface shrinkage are improved, which means that the method of this example improves the strength of the powder metallurgy high tungsten tantalum alloy and also greatly improves the plasticity thereof.

The above description is only of the preferred embodiments of the present invention, and is not intended to limit the present invention. Any simple modification, variation and equivalent variation of the above embodiments according to the technical substance of the invention still fall within the scope of the technical solution of the invention.

Claims

1. A method for improving plasticity of powder metallurgy high tungsten tantalum alloy is characterized in that the method adopts a process of combining sponge zirconium adsorption and high-temperature vacuum heat treatment at high temperature to treat a high tungsten tantalum alloy product after hot isostatic pressing in the preparation process of the powder metallurgy high tungsten tantalum alloy; the high tungsten tantalum alloy product comprises a TaW10 alloy or a TaW12 alloy; the method comprises the following specific processes: removing a titanium sheath or a niobium sheath from the high tungsten tantalum alloy product subjected to hot isostatic pressing by machining, then placing the high tungsten tantalum alloy product into a crucible, filling with sponge zirconium, integrally placing the crucible into a vacuum furnace for primary heat treatment, taking out the sponge zirconium after the furnace temperature is reduced to room temperature, placing the high tungsten tantalum alloy product and the crucible into the vacuum furnace for secondary heat treatment, and discharging after cooling; the system of the primary heat treatment is as follows: preserving heat for 1-3 h at 1300-1450 ℃, and keeping the vacuum degree at 5.0x10 in the heating, preserving heat and cooling process of one-time heat treatment ^-1 ～5×10 ^-3 Pa; the secondary heat treatment system is as follows: preserving heat for 2-4 h at 2160-2200 ℃, and keeping vacuum degree at 5.0X10 in the heating, preserving heat and cooling process of the secondary heat treatment ^-2 ～5×10 ^-4 Pa。

2. The method for improving the plasticity of the powder metallurgy high tungsten tantalum alloy according to claim 1, wherein the one-time heat treatment system is as follows: preserving heat for 2h at 1350 ℃, and the secondary heat treatment system is as follows: preserving the heat for 2 hours at 2160-2180 ℃.

3. The method for improving the plasticity of the powder metallurgy high tungsten tantalum alloy according to claim 1, wherein the heating rate of the primary heat treatment and the secondary heat treatment is 5 ℃/min-17 ℃/min.

4. The method for improving the plasticity of the powder metallurgy high tungsten tantalum alloy according to claim 1, wherein the sponge zirconium is industrial sponge zirconium with the brand number of HZr-01 and has the particle size of 3-8 mm.

5. The method of claim 1, wherein the sponge zirconium is fully embedded in the high tungsten tantalum alloy article.

6. The method for improving the plasticity of the powder metallurgy high-tungsten tantalum alloy according to claim 1, wherein the vacuum furnace is a high-temperature vacuum annealing furnace, a tungsten wire mesh is adopted as a heating body, and a molybdenum plate, a tantalum plate or a tungsten plate is adopted as a crucible and a heat shield.