CN114888291A - Method for improving plasticity of powder metallurgy high-tungsten tantalum alloy - Google Patents

Abstract

The invention discloses a method for improving the plasticity of powder metallurgy high tungsten tantalum alloy. The method adopts the technology of sponge zirconium adsorption at high temperature combined with high temperature vacuum heat treatment. Tungsten-tantalum alloy products are processed. The present invention adopts a two-step heat treatment method. First, a sponge zirconium deoxidizer is used to adsorb oxygen in the high-tungsten-tantalum alloy products, and then high-temperature vacuum heat treatment is used to promote the volatilization of oxygen and oxides in the high-tungsten-tantalum alloy products, and promote the solid solution oxygen in the grain boundary. The diffusion escape in the tungsten alloy effectively reduces the oxygen content, purifies the grain boundary, improves the bonding force of the grain boundary, and releases the internal stress generated by hot isostatic pressing, which greatly improves the strength of the alloy while ensuring the high strength of the tungsten-tantalum alloy. plasticity.

Description

A method for improving the plasticity of powder metallurgy high tungsten-tantalum alloy

technical field

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

Background technique

Tungsten-tantalum alloy is a very important and widely used material in tantalum alloys with excellent high temperature resistance, impact and dynamic mechanical properties, especially high-tungsten-tantalum alloys, which are mostly used in some extremely harsh working conditions. High tungsten-tantalum alloys have higher creep strength and low creep rate, so these tantalum-tungsten alloys are better candidates for heat-resistant washout components because of their high density, high melting point, good corrosion resistance, and good workability , weldability and other characteristics, in recent years has been gradually used in weapons, aerospace and other fields. At present, the mature high-tungsten tantalum alloys used in my country mainly include TaW10 and TaW12. As refractory metal alloys, tungsten-tantalum series alloys are easily oxidized at high temperatures, and are generally prepared by vacuum electron beam melting. The tungsten-tantalum ingots smelted by electron beams have low impurity and interstitial element content, uniform composition, good plasticity, and the oxygen content can be easily controlled below 0.01%; while the TaW10 and TaW12 alloys smelted by electron beams have low elongation after pressure processing. reach 20% to 40%. High-tungsten-tantalum alloys have high strength and are easy to oxidize, which makes pressure processing and forming difficult. Although the current conventional plate and bar production process is relatively mature, due to the limitation of the size of electron beam melting ingots, some large-sized alloy components, Special-shaped parts, thin (thick) wall cylindrical parts, etc. are difficult to achieve by electron beam smelting combined with pressure processing. Therefore, such products and components can only be prepared by powder metallurgy.

Hot isostatic pressing (HIP) is to apply isostatic pressure to powder metallurgy products or green compacts through high-pressure gas at high temperature to eliminate internal defects and pores of the products, and at the same time to cause diffusion adhesion at the grain interface at high temperature. It is a technology that improves the mechanical properties of products and realizes complete densification. In recent years, hot isostatic pressing technology has been gradually applied in the processing of refractory alloys. In the method, the uniformly mixed alloy powder is put into a pre-formed casing for pressing to obtain a billet with a density close to the theoretical density, and then the desired product is obtained by simple machining. This method has a short process and is easy to control, is very suitable for the preparation of special-shaped parts, and has a high yield.

The most common preparation method of raw material powder used in powder metallurgy high tungsten-tantalum alloy products is to prepare by vacuum smelting alloy ingot whose composition meets the national standard by hydrogenation dehydrogenation or plasma rotating electrode. Among them, the advantage of using alloy ingot hydrogenation to make powder is that Ta and W elements have been alloyed, and the process of powder making only changes in physical shape, and the powder particles are still alloys, which avoids the segregation of elements. However, even if ingots with extremely low O content (below 0.01%) are used, due to the long-term high-temperature hydrogenation, dehydrogenation and mechanical crushing, it is inevitable that the oxygen content in the powder will increase greatly (generally greater than 0.06%). Compared with the powder made by rotating electrode powder, the oxygen content of the powder obtained by hydrogenation and dehydrogenation is lower. However, because the method adopts argon protection, the inevitable oxygen element (about 0.1%) in the argon will be adsorbed by the powder, and there will still be a certain amount of oxygen. Oxygenation. In the process of hot isostatic pressing of this kind of powder with high oxygen content, because the envelope is completely sealed, the oxygen cannot be removed, and eventually all of it is concentrated at the grain boundary, resulting in a sharp drop in the plasticity of the product, which not only affects the later machining, but also It also has a great impact on the mechanical properties and reliability of alloy products.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a method for improving the plasticity of powder metallurgy high tungsten-tantalum alloy in view of the above-mentioned deficiencies of the prior art. For the high-tungsten-tantalum alloy products after hot isostatic pressing, the method first uses a sponge zirconium deoxidizer to adsorb oxygen in the high-tungsten-tantalum alloy products, and then uses high-temperature vacuum heat treatment to promote the volatilization of oxygen and oxides in the high-tungsten-tantalum alloy products. The oxygen content is effectively reduced, the grain boundary bonding force is improved, and the plasticity of the alloy is greatly improved while ensuring the strength of the high tungsten-tantalum alloy.

In order to solve the above-mentioned technical problems, the technical scheme adopted in the present invention is: a method for improving the plasticity of powder metallurgy high tungsten-tantalum alloy, characterized in that the method adopts the technology of sponge zirconium adsorption at high temperature combined with high temperature vacuum heat treatment, which has a high impact on powder metallurgy. In the preparation process of the tungsten-tantalum alloy, the high-tungsten-tantalum alloy product after hot isostatic pressing is processed; the composition of the high-tungsten-tantalum alloy product is TaW10 alloy or TaW12 alloy.

The present invention aims at the high-tungsten-tantalum alloy products after hot isostatic pressing in the preparation process of the powder metallurgy high-tungsten-tantalum alloy. Through a two-step heat treatment method, sponge zirconium is used as a deoxidizer to adsorb oxygen in the high-tungsten-tantalum alloy products. , and then high-temperature vacuum heat treatment is used to further promote the volatilization of solid solution oxygen and residual oxides in high-tungsten-tantalum alloy products, effectively reduce the oxygen content in high-tungsten-tantalum alloy products, purify grain boundaries, and combine the effect of high-temperature sintering , which improves the bonding force of the grain boundary, thereby greatly improving the plasticity of the alloy, and solving the problem that the plasticity of high-tungsten-tantalum alloy products decreases sharply due to oxygen enrichment at the grain boundary during the hot isostatic pressing process.

The above-mentioned method for improving the plasticity of powder metallurgy high-tungsten-tantalum alloy is characterized in that the specific process of the method is: removing the titanium sheath or niobium sheath from the high-tungsten-tantalum alloy product after hot isostatic pressing by machining, Then put it in a crucible and fill it with sponge zirconium, and put it into a vacuum furnace for a heat treatment. After the furnace temperature drops to room temperature, take out the sponge zirconium, and then put the high tungsten-tantalum alloy product together with the crucible into the vacuum furnace for a second time. Heat treatment, after cooling, the furnace is released; the system of the first heat treatment is: heat preservation at 1300 ° C ~ 1450 ° C for 1 h ~ 3 h, and maintain a vacuum degree of 5.0 × 10 ^-1 ~ 5 × 10 during the heating, heat preservation and cooling process of the first heat treatment ^-3 Pa; the system of the secondary heat treatment is: keep the temperature at 2160°C～2200°C for 2h～4h, and keep the vacuum degree at 5.0×10 ^-2 ～5×10 during the heating, heat preservation and cooling process of the secondary heat treatment ^-4 Pa.

Tantalum and tantalum alloys begin to absorb oxygen above 400°C, and the oxygen content will increase even in vacuum heat treatment. Oxygen has a solid solution strengthening effect in tantalum and tantalum alloys, which increases the hardness by 1 to 3 times, but greatly reduces it. The plasticity of tantalum and tantalum alloys, therefore, the dissolved oxygen in tantalum and tantalum alloys, as a harmful element that damages plasticity and toughness, should be minimized or removed. In view of this situation, the present invention creatively uses a two-step heat treatment process: first, the hot isostatic pressing high tungsten-tantalum alloy product after removing the jacket is placed in a crucible and filled with sponge zirconium to perform a heat treatment in a vacuum state, and a limited time The temperature of heat treatment is 1300℃～1450℃. Oxygen has a low diffusion rate in high-tungsten-tantalum alloy products at this temperature, so that the oxides of tantalum in high-tungsten-tantalum alloy products are volatilized and mixed with the surrounding sponge. Zirconium has a strong adsorption effect, thereby effectively removing oxygen in high-tungsten-tantalum alloy products, and avoiding the melting failure of zirconium sponge due to excessive temperature; Heat treatment, and the temperature of the secondary heat treatment is limited to 2160 ℃ ~ 2200 ℃, because the low-valent oxides formed by tantalum and oxygen in the high-tungsten-tantalum alloy products have been adsorbed and volatilized during the first heat treatment, the remaining solid solution oxygen at 2100 At a high temperature above ℃, it begins to diffuse out and escape, so that the grain boundaries of the alloy in the high-tungsten-tantalum alloy products are fully purified. The bonding force and the internal stress generated by hot isostatic pressing are released, which greatly improves the plasticity of the high tungsten-tantalum alloy.

The above-mentioned method for improving the plasticity of powder metallurgy high tungsten-tantalum alloy is characterized in that the system of the first heat treatment is: keeping at 1350°C for 2 hours, and the second heat treatment system is: keeping at 2180°C～2200°C for 2 hours .

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

The above-mentioned method for improving the plasticity of powder metallurgy high tungsten-tantalum alloy is characterized in that the zirconium sponge is industrial zirconium sponge with the brand name HZr-01, and the particle size is 3mm-8mm. The impurity and gas content in the sponge zirconium are low, the quality is good, the particle size is small, and the adsorption effect is good, and the adsorption capacity of the sponge zirconium to the volatilized oxides in the high tungsten-tantalum alloy product is improved. Generally, in order to ensure the adsorption effect of zirconium sponge on oxides, the zirconium sponge used in a heat treatment process cannot be reused.

The above-mentioned method for improving the plasticity of powder metallurgy high-tungsten-tantalum alloy is characterized in that the degree of burying of the zirconium sponge is to completely bury the high-tungsten-tantalum alloy product. The invention adopts sponge zirconium to bury high-tungsten-tantalum alloy products to complete burial and coating, increases the contact area between sponge zirconium and high-tungsten-tantalum alloy products, improves the adsorption effect of sponge zirconium on oxygen, and is beneficial to high-tungsten-tantalum alloy products sufficient oxygen removal.

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

The room temperature in the present invention is 25°C to 35°C.

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

1. The present invention adopts a two-step heat treatment method. First, sponge zirconium deoxidizer is used to adsorb oxygen in high-tungsten-tantalum alloy products, and then high-temperature vacuum heat treatment is used to promote the volatilization of oxygen and oxides in high-tungsten-tantalum alloy products, effectively reducing the oxygen content. , which improves the bonding force of grain boundaries, and greatly improves the plasticity of the alloy while ensuring the strength of high tungsten-tantalum alloy.

2. Compared with using only vacuum furnace for heating and deoxidizing, the present invention creatively uses sponge zirconium as the vacuum adsorbent in the furnace, which obviously improves the deoxidizing effect, and the process is simple and easy to carry out.

3. The present invention removes tantalum oxide and solid solution oxygen in high-tungsten-tantalum alloy products step by step by accurately controlling the temperature of two heat treatments, so that the grain boundary is purified, and high temperature sintering is realized to form metallurgical bonding, which improves the intergranular performance. The bonding force and the internal stress generated by hot isostatic pressing are released, which greatly improves the plasticity of the high tungsten-tantalum alloy.

4. The equipment used in the present invention are all existing common equipment in the industry, no special equipment is required, the equipment requirements are not high, and the condition control process is simple and easy to implement.

The technical solutions of the present invention will be further described in detail below through the accompanying drawings and embodiments.

Description of drawings

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

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

FIG. 3 is a physical diagram of a tensile fracture of the TaW12 alloy prepared in Example 3 of the present invention.

FIG. 4 is a physical diagram of a tensile fracture of the TaW12 alloy prepared in Example 4 of the present invention.

Detailed ways

Example 1

The specific process of this embodiment is as follows: the TaW10 alloy product after hot isostatic pressing is processed by a lathe to remove the titanium sheath, and the metal cleaning agent is used to clean it and dry the moisture; In the crucible, the sponge zirconium with the grade of HZr-01 and the particle size of 3mm to 8mm is used to fill the TaW10 alloy products completely. The alloy product together with the tungsten crucible is put into a vacuum furnace for secondary heat treatment, and the furnace is cooled to below 80 °C and released to obtain TaW10 alloy;

The system of the primary heat treatment is as follows: under the condition of vacuum degree of 5.0×10 ^-1 to 5×10 ^-3 Pa, the temperature is raised from room temperature to 1350° C. within 1.5h and kept for 2h, and then cooled with the furnace; the secondary heat treatment The system is as follows: under the condition of vacuum degree of 5.0×10 ^-2 ~ 5×10 ^-4 Pa, the temperature is raised from room temperature to 2180°C within 2.5h and kept for 2h, and then cooled with the furnace;

The vacuum furnace is a high-temperature vacuum annealing furnace, and adopts a tungsten wire mesh as a heating element, and adopts a molybdenum plate, a tantalum plate or a tungsten plate as a crucible and a heat shield.

Samples were taken from the TaW10 alloy products cleaned and dried by the metal cleaning agent in this example as the samples before treatment, and samples were taken from the obtained TaW10 alloys as the samples after treatment. The sampling position for the performance test is the upper end face, and the sampling position for the oxygen content analysis is the upper middle and lower middle of the outer circumferential surface. The results are shown in Table 1 below.

Table 1

"/" in Table 1 indicates that the sample is directly brittle fracture without this index.

It can be seen from Table 1 that the oxygen mass content in the TaW10 alloy obtained after the two-step heat treatment in this example is significantly lower than that of the TaW10 alloy product after hot isostatic pressing, and the strength including tensile strength and yield strength is significantly improved, elongation Both the shrinkage rate and the end face shrinkage rate are improved, indicating that the method of this embodiment can greatly improve the plasticity of the powder metallurgy high tungsten-tantalum alloy while improving the strength of the powder metallurgy high tungsten-tantalum alloy.

Figure 1 shows the SEM image of the tensile fracture of the TaW10 alloy prepared in this example. It can be seen from Figure 1 that there is no obvious interface between the grains in the tensile fracture of the TaW10 alloy, and the dimples become larger and deeper. The slip phenomenon is more obvious, and a large number of shrinkage holes appear at the bottom of the dimple, which is characterized by plastic deformation.

Example 2

The specific process of this embodiment is as follows: the TaW10 alloy product after hot isostatic pressing is processed by a lathe to remove the titanium sheath, and the metal cleaning agent is used to clean it and dry the moisture; In the crucible, the sponge zirconium with the grade of HZr-01 and the particle size of 3mm to 8mm is used to fill the TaW10 alloy products completely. The alloy product together with the tungsten crucible is put into a vacuum furnace for secondary heat treatment, and the furnace is cooled to below 80 °C and released to obtain TaW10 alloy;

The system of the first heat treatment is: under the condition of vacuum degree of 5.0 × 10 ^-1 to 5 × 10 ^-3 Pa, the temperature is raised from room temperature to 1300 ° C within 4.25h, and kept for 3 hours, and then cooled with the furnace; the second heat treatment The system is as follows: under the condition of vacuum degree of 5.0×10 ^-2 to 5×10 ^-4 Pa, the temperature is raised from room temperature to 2200°C within 7.25h and kept for 4h, and then cooled with the furnace;

The vacuum furnace is a high-temperature vacuum annealing furnace, and adopts a tungsten wire mesh as a heating element, and adopts a molybdenum plate, a tantalum plate or a tungsten plate as a crucible and a heat shield.

Samples were taken from the TaW10 alloy products cleaned and dried by the metal cleaning agent in this example as the samples before treatment, and samples were taken from the obtained TaW10 alloys as the samples after treatment. The sampling position for the performance test is the upper end face, and the sampling position for the oxygen content analysis is the upper middle and lower middle of the outer circumferential surface. The results are shown in Table 2 below.

Table 2

"/" in Table 2 indicates that the sample is directly brittle without this index.

It can be seen from Table 2 that the oxygen mass content in the TaW10 alloy obtained after the two-step heat treatment in this example is significantly lower than that of the TaW10 alloy product after hot isostatic pressing, and the strength including tensile strength and yield strength is significantly improved, elongation Both the shrinkage rate and the end face shrinkage rate are improved, indicating that the method of this embodiment can greatly improve the plasticity of the powder metallurgy high tungsten-tantalum alloy while improving the strength of the powder metallurgy high tungsten-tantalum alloy.

Fig. 2 is a SEM image of the tensile fracture of the TaW10 alloy prepared in this example. It can be seen from Fig. 2 that the slip phenomenon on the dimple in the tensile fracture of the TaW10 alloy is obvious, and a large number of shrinkage holes appear at the bottom of the dimple. is a typical plastic deformation.

Example 3

The specific process of this embodiment is as follows: the TaW12 alloy product after hot isostatic pressing is machined to remove the titanium sheath, and metal cleaning agent is used to clean it and dry the moisture; the dried TaW12 alloy product is placed in a tungsten In the crucible, the sponge zirconium with the grade of HZr-01 and the particle size of 3mm to 8mm is used to bury the TaW12 alloy products completely. The alloy product together with the tungsten crucible is put into a vacuum furnace for secondary heat treatment, and the furnace is cooled to below 80 °C and released to obtain TaW12 alloy;

The system of the primary heat treatment is as follows: under the condition of vacuum degree of 5.0×10 ^-1 to 5×10 ^-3 Pa, the temperature is raised from room temperature to 1350° C. within 2 hours and kept for 2 hours, and then cooled with the furnace; The system is as follows: under the condition of vacuum degree of 5.0×10 ^-2 to 5×10 ^-4 Pa, the temperature is raised from room temperature to 2160°C within 3h and kept for 2h, and then cooled with the furnace;

The vacuum furnace is a high-temperature vacuum annealing furnace, and adopts a tungsten wire mesh as a heating element, and adopts a molybdenum plate, a tantalum plate or a tungsten plate as a crucible and a heat shield.

Samples were taken from the TaW12 alloy products cleaned and dried by the metal cleaning agent in this example as samples before treatment, and samples were taken from the obtained TaW12 alloys as samples after treatment. The room temperature mechanical property test and oxygen content analysis were carried out respectively. The sampling position of the performance test is the upper end face, and the sampling position of the oxygen content analysis is the upper middle and lower middle of the outer circumferential surface. The results are shown in Table 3 below.

table 3

"/" in Table 3 indicates that the sample is directly brittle fracture without this index.

It can be seen from Table 3 that the oxygen mass content in the TaW12 alloy obtained after the two-step heat treatment in this example is significantly lower than that of the TaW12 alloy product after hot isostatic pressing, and the strength including tensile strength and yield strength is significantly improved, elongation Both the shrinkage rate and the end face shrinkage rate are improved, indicating that the method of this embodiment can greatly improve the plasticity of the powder metallurgy high tungsten-tantalum alloy while improving the strength of the powder metallurgy high tungsten-tantalum alloy.

Fig. 3 is a physical diagram of the tensile fracture surface of the TaW12 alloy prepared in this embodiment. It can be seen from Fig. 3 that the TaW12 alloy has obvious necking phenomenon after being stretched, showing good plastic fracture characteristics.

Example 4

The specific process of this embodiment is as follows: the TaW12 alloy product after hot isostatic pressing is machined to remove the titanium sheath, and metal cleaning agent is used to clean it and dry the moisture; the dried TaW12 alloy product is placed in a tungsten In the crucible, the sponge zirconium with the grade of HZr-01 and the particle size of 3mm to 8mm is used to bury the TaW12 alloy products completely. The alloy product together with the tungsten crucible is put into a vacuum furnace for secondary heat treatment, and the furnace is cooled to below 80 °C and released to obtain TaW12 alloy;

The system of the first heat treatment is as follows: under the condition of vacuum degree of 5.0×10 ^-1 to 5×10 ^-3 Pa, the temperature is raised from room temperature to 1300° C. within 1.5h and kept for 1h, and then cooled with the furnace; the second heat treatment The system is as follows: under the condition of vacuum degree of 5.0×10 ^-2 to 5×10 ^-4 Pa, the temperature is raised from room temperature to 2180°C within 2.5h and kept for 2h, and then cooled with the furnace.

Samples were taken from the TaW12 alloy products cleaned and dried by the metal cleaning agent in this example as samples before treatment, and samples were taken from the obtained TaW12 alloys as samples after treatment. The room temperature mechanical property test and oxygen content analysis were carried out respectively. The sampling position of the performance test is the upper end face, and the sampling position of the oxygen content analysis is the upper middle and lower middle of the outer circumferential surface. The results are shown in Table 4 below.

Table 4

"/" in Table 4 indicates that the sample is directly brittle fracture without this index.

It can be seen from Table 4 that the oxygen mass content in the TaW12 alloy obtained after the two-step heat treatment in this example is significantly lower than that of the TaW12 alloy product after hot isostatic pressing, and the strength including tensile strength and yield strength is significantly improved, elongation Both the shrinkage rate and the end face shrinkage rate are improved, indicating that the method of this embodiment can greatly improve the plasticity of the powder metallurgy high tungsten-tantalum alloy while improving the strength of the powder metallurgy high tungsten-tantalum alloy.

Fig. 4 is a physical diagram of the tensile fracture of the TaW12 alloy prepared in this example. It can be seen from Figure 4 that the tensile fracture of the TaW12 alloy is point-shaped, and the end face shrinkage rate is high, showing obvious plastic fracture characteristics.

Example 5

The specific process of this embodiment is as follows: the TaW10 alloy product after hot isostatic pressing is processed by a lathe to remove the titanium sheath, and the metal cleaning agent is used to clean it and dry the moisture; In the crucible, the sponge zirconium with the grade of HZr-01 and the particle size of 3mm to 8mm is used to fill the TaW10 alloy products completely. The alloy product together with the tungsten crucible is put into a vacuum furnace for secondary heat treatment, and the furnace is cooled to below 80 °C and released to obtain TaW10 alloy;

The system of the primary heat treatment is as follows: under the condition of vacuum degree of 5.0×10 ^-1 to 5×10 ^-3 Pa, the temperature is raised from room temperature to 1450° C. within 1.4 hours and kept for 1 hour, and then cooled with the furnace; the secondary heat treatment The system is as follows: under the condition of vacuum degree of 5.0×10 ^-2 to 5×10 ^-4 Pa, the temperature is raised from room temperature to 2160°C within 2h and kept for 2h, and then cooled with the furnace;

The vacuum furnace is a high-temperature vacuum annealing furnace, and adopts a tungsten wire mesh as a heating element, and adopts a molybdenum plate, a tantalum plate or a tungsten plate as a crucible and a heat shield.

Samples were taken from the TaW10 alloy products cleaned and dried by the metal cleaning agent in this example as the samples before treatment, and samples were taken from the obtained TaW10 alloys as the samples after treatment. The sampling position of the performance test is the upper end face, and the sampling position of the oxygen content analysis is the upper middle and lower middle of the outer circumferential surface. The results are shown in Table 5 below.

table 5

"/" in Table 5 indicates that the sample is directly brittle fracture without this index.

It can be seen from Table 5 that the oxygen mass content in the TaW10 alloy obtained after the two-step heat treatment in this example is significantly lower than that of the TaW10 alloy product after hot isostatic pressing, and the strength including tensile strength and yield strength is significantly improved, elongation Both the shrinkage rate and the end face shrinkage rate are improved, indicating that the method of this embodiment can greatly improve the plasticity of the powder metallurgy high tungsten-tantalum alloy while improving the strength of the powder metallurgy high tungsten-tantalum alloy.

Example 6

The specific process of this embodiment is as follows: the TaW12 alloy product after hot isostatic pressing is machined to remove the titanium sheath, and metal cleaning agent is used to clean it and dry the moisture; the dried TaW12 alloy product is placed in a tungsten In the crucible, the sponge zirconium with the grade of HZr-01 and the particle size of 3mm to 8mm is used to bury the TaW12 alloy products completely. The alloy product together with the tungsten crucible is put into a vacuum furnace for secondary heat treatment, and the furnace is cooled to below 80 °C and released to obtain TaW12 alloy;

The system of the primary heat treatment is as follows: under the condition of vacuum degree of 5.0×10 ^-1 to 5×10 ^-3 Pa, the temperature is raised from room temperature to 1450° C. within 1.4 hours and kept for 3 hours, and then cooled with the furnace; the secondary heat treatment The system is as follows: under the condition of vacuum degree of 5.0×10 ^-2 ~ 5×10 ^-4 Pa, the temperature is raised from room temperature to 2200°C within 2.1h and kept for 4h, and then cooled with the furnace;

The vacuum furnace is a high-temperature vacuum annealing furnace, and adopts a tungsten wire mesh as a heating element, and adopts a molybdenum plate, a tantalum plate or a tungsten plate as a crucible and a heat shield.

Samples were taken from the TaW12 alloy products cleaned and dried by the metal cleaning agent in this example as samples before treatment, and samples were taken from the obtained TaW12 alloys as samples after treatment. The room temperature mechanical property test and oxygen content analysis were carried out respectively. The sampling position of the performance test is the upper end face, and the sampling position of the oxygen content analysis is the upper middle and lower middle of the outer circumferential surface. The results are shown in Table 6 below.

Table 6

"/" in Table 6 indicates that the sample is directly brittle fracture without this index.

It can be seen from Table 6 that the oxygen mass content in the TaW12 alloy obtained after the two-step heat treatment in this example is significantly lower than that of the TaW12 alloy product after hot isostatic pressing, and the strength including tensile strength and yield strength is significantly improved, elongation Both the shrinkage rate and the end face shrinkage rate are improved, indicating that the method of this embodiment can greatly improve the plasticity of the powder metallurgy high tungsten-tantalum alloy while improving the strength of the powder metallurgy high tungsten-tantalum alloy.

The above descriptions are only preferred embodiments of the present invention, and do not limit the present invention in any way. Any simple modifications, changes and equivalent changes made to the above embodiments according to the technical essence of the invention still fall within the protection scope of the technical solutions of the present invention.

Claims (7)

1. a method for improving the plasticity of powder metallurgy high tungsten-tantalum alloy, is characterized in that, the method adopts sponge zirconium adsorption under high temperature combined with the technology of high temperature vacuum heat treatment, after hot isostatic pressing in the powder metallurgy high tungsten-tantalum alloy preparation process. The high-tungsten-tantalum alloy product is processed; the composition of the high-tungsten-tantalum alloy product is TaW10 alloy or TaW12 alloy. 2. a kind of method that improves the plasticity of powder metallurgy high tungsten-tantalum alloy according to claim 1, is characterized in that, the concrete process of this method is: the high-tungsten-tantalum alloy product after hot isostatic pressing is removed titanium through machining The jacket or niobium jacket is then placed in a crucible and filled with sponge zirconium. The whole is placed in a vacuum furnace for a heat treatment. After the furnace temperature drops to room temperature, the sponge zirconium is taken out, and then the high tungsten-tantalum alloy products are placed in the crucible. Put it into a vacuum furnace for secondary heat treatment, and then release it after cooling; the system of the primary heat treatment is: keep the temperature at 1300℃～1450℃ for 1h～3h, and keep the vacuum degree at 5.0× during the heating, heat preservation and cooling process of the primary heat treatment 10 ^-1 to 5×10 ^-3 Pa; the system of the secondary heat treatment is: keep the temperature at 2160°C to 2200°C for 2h to 4h, and keep the vacuum degree at 5.0× during the heating, heat preservation and cooling of the secondary heat treatment. 10 ^-2 to 5×10 ^{- 4} Pa. 3. The method for improving the plasticity of powder metallurgy high tungsten-tantalum alloy according to claim 2, wherein the system of the primary heat treatment is: heat preservation at 1350°C for 2h, and the system of the secondary heat treatment is: at 2160 Incubate at ℃～2180℃ for 2h. 4 . The method for improving the plasticity of powder metallurgy high tungsten-tantalum alloy according to claim 2 , wherein the heating rates of the primary heat treatment and the secondary heat treatment are both 5° C./min to 17° C./min. 5 . 5. A method for improving the plasticity of powder metallurgy high tungsten-tantalum alloy according to claim 1 or 2, wherein the zirconium sponge is an industrial zirconium sponge with the trade name HZr-01, and the particle size is 3mm to 8mm. 6 . The method for improving the plasticity of powder metallurgy high tungsten-tantalum alloy according to claim 2 , wherein, the degree of burying the zirconium sponge is to completely bury the high tungsten-tantalum alloy product. 7 . 7. The method for improving the plasticity of powder metallurgy high tungsten-tantalum alloy according to claim 2, wherein the vacuum furnace is a high-temperature vacuum annealing furnace, and a tungsten wire mesh is used as a heating element, and a molybdenum plate, a tantalum Plate or tungsten plate as crucible and heat shield.

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