Preparation method of high-entropy alloy bar with uniform components and no shrinkage cavity

Abstract

The invention discloses a preparation method of a uniform-component shrinkage-cavity-free high-entropy alloy bar, the high-entropy alloy bar which is uniform in component and free of shrinkage cavity defects is obtained by adopting a mode of combining intermittent feeding and an ingot pulling process, and in addition, the invention further discloses a specific method: the high-entropy alloy bar which is uniform in component and free of shrinkage cavity defects is obtained by adopting the mode of combining the intermittent feeding and the ingot pulling process. And melting the metal raw materials in batches and pulling ingots to obtain the high-entropy alloy bar with uniform components and no shrinkage cavity. According to the method, the mixture is sequentially smelted in batches, so that the uniformity of chemical components is ensured, the intangible loss of raw materials is reduced, liquid metal feeding at a solid-liquid interface is ensured all the time, and the shrinkage cavity defect is avoided, so that the yield of the high-entropy alloy bar is increased; and the high-quality high-entropy alloy bar with uniform chemical components and no obvious casting defects is obtained, the cost is greatly reduced, the raw materials are saved, the utilization rate of the materials is improved, and the method has the characteristics of high efficiency, high yield, low loss and low energy consumption.

Description

Technical Field

[0001] The invention belongs to the technical field of high entropy alloy rod preparation, and in particular relates to a method for preparing a high entropy alloy rod with uniform composition and no shrinkage cavity. Background Art

[0002] Due to its multi-principal element characteristics, high entropy alloys have unique high entropy effects, lattice distortion effects, hysteresis diffusion effects and cocktail effects, and thus have better mechanical properties, corrosion resistance and high temperature resistance than traditional alloys, showing great application potential in the fields of aerospace, weapons and equipment, and biomedicine. However, it is precisely because of the high content of high entropy alloys that the preparation process of high entropy alloys is more demanding and difficult.

[0003] At present, the preparation method of high entropy alloy rods is mainly to first obtain high entropy alloy ingots by smelting, and then obtain high entropy alloy rods by secondary smelting + casting or hot extrusion (application number is 202210785207.9, application number is 202210360808.5). However, secondary smelting is usually inseparable from the assistance of mechanical processing such as wire cutting and sawing machines, which not only easily introduces impurities, but also causes some invisible loss of raw materials. The casting process is difficult to avoid the presence of shrinkage cavities in the alloy. The hot extrusion process not only requires a large number of experiments to explore the hot processing process parameters of the alloy, but also is difficult to complete for alloys that are prone to hot cracks. Therefore, these methods will eventually lead to high preparation costs and low efficiency, which seriously restricts the industrial promotion and application of high entropy alloys. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for preparing a high-entropy alloy bar with uniform composition and no shrinkage cavity in view of the deficiencies of the above-mentioned prior art. The method ensures the uniformity of chemical composition, reduces the invisible loss of raw materials, ensures that there is always liquid metal shrinkage at the solid-liquid interface, avoids the generation of shrinkage cavity defects, thereby improving the yield rate of high-entropy alloy bars, and prepares high-quality high-entropy alloy bars with uniform chemical composition and no obvious casting defects.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for preparing a high-entropy alloy rod with uniform composition and no shrinkage cavity, characterized in that the method adopts a combination of intermittent feeding and ingot pulling process to obtain a high-entropy alloy rod with uniform composition and no shrinkage cavity defects.

[0006] The above-mentioned method for preparing a high-entropy alloy bar with uniform composition and no shrinkage cavity is characterized in that the method comprises the following steps: Step 1: Grind the surface of the metal raw material, then perform ultrasonic cleaning and vacuum drying to obtain clean metal raw material, and clean the water-cooled copper crucible in the vacuum ingot pulling furnace; Step 2: Mix the clean metal raw materials obtained in step 1 to obtain a mixture, and then divide the mixture into batches. Then, the first batch of the mixture is directly placed in the water-cooled copper crucible in the vacuum ingot pulling furnace cleaned in step 1, and the remaining batches of the mixture are placed in the feeder in sequence; Step 3, installing the ingot guide in the vacuum ingot pulling furnace loaded with the first batch of mixed materials in step 2, and then evacuating the vacuum ingot pulling furnace, and then filling it with inert gas to obtain a vacuum ingot pulling furnace to be smelted; Step 4: Turn on the power of the vacuum ingot pulling furnace to be smelted obtained in step 3, control the smelting power, and completely melt the first batch of clean metal raw materials in the water-cooled copper crucible to form a stable molten pool in the vacuum ingot pulling furnace; Step 5, turning on the ingot pulling switch of the vacuum ingot pulling furnace that forms the stable molten pool in step 4, pulling the ingot and simultaneously reducing the smelting power; Step 6: When the liquid level of the stable molten pool in step 5 drops to 1 / 2 to 1 / 3 of the original liquid level, turn off the ingot pulling switch, wait for its speed to return to zero, turn on the feeder in step 2 to feed the second batch of mixed materials, then increase the smelting power, and form a stable molten pool again; Step 7, repeating steps 5 and 6 until all batches of mixed materials are put in and the ingots are drawn, and a high entropy alloy billet is obtained after cooling; Step 8: The high entropy alloy rod blank obtained in step 7 is subjected to surface peeling treatment to obtain a high entropy alloy rod with uniform composition and no shrinkage cavities.

[0007] The present invention removes scale and other impurities on the surface of the metal raw material by grinding and ultrasonic cleaning, thereby ensuring the performance of the high entropy alloy rod material. By dividing the mixed material into batches and smelting them in sequence, i.e., intermittent feeding, the uniformity of the chemical composition is ensured, and the pre-treatment process and mechanical processing process of the subsequent smelting are avoided, thereby reducing the invisible loss of the raw materials. In the process of batch smelting, the ingots are pulled in batches, thereby ensuring that there is always liquid metal shrinkage at the solid-liquid interface, avoiding the shrinkage cavity defects that are easy to be generated in the casting process, thereby improving the high entropy alloy rod material. The yield of high-entropy alloy rods is improved, and the liquid level of the stable molten pool is controlled to be reduced to 1 / 2~1 / 3 of the original liquid level before stopping the ingot pulling and feeding the next time, so as to ensure the efficiency of alloy melting and the stability of the liquid level, prevent the liquid level from being too high to affect the ingot pulling efficiency, and the liquid level is too low to add material to cause liquid splashing, thereby ensuring the uniformity of ingot pulling. The prepared high-entropy alloy rods do not require subsequent hot extrusion forming, and can be used to prepare high-entropy alloy components that are difficult to process at high temperatures, broadening the preparation range of high-entropy alloy rods, and obtaining high-entropy alloy rods with uniform composition and no shrinkage cavities.

[0008] The above method is characterized in that the metal raw material in step 1 is Co, Cr, Fe, Ni, Al, Ti metal particles, the mass purity of the metal raw material is greater than 99.5%, and the particle size is not greater than 10 mm. The present invention prepares high entropy alloy bars of different compositions by controlling the composition of the metal raw material, and by controlling the mass purity and particle size, it is convenient for batching, feeding and smelting, while ensuring the performance of the high entropy alloy bar.

[0009] The above method is characterized in that the batching in step 2 is divided into 3 to 8 batches, and the composition of the mixed material in each batch is consistent. The present invention controls the number of batches, controls the quality of the stable molten pool and the ingot formed by each smelting, ensures the efficiency of the metal raw material melting and the stability of the molten pool liquid level by performing the smelting in batches, and prevents the instability of the molten pool and uneven ingot pulling caused by adding too much metal raw material at one time.

[0010] The above method is characterized in that the composition of the starter in step 3 is consistent with the composition of the mixed material in step 2. The present invention ensures uniform chemical composition in the high entropy alloy bar by controlling the composition of the starter, avoiding affecting its chemical composition.

[0011] The above method is characterized in that the vacuuming in step 3 is to evacuate to a vacuum degree not greater than 7×10 - 3 Pa, the inert gas is high-purity argon with a mass purity greater than 99.9%, and the inert gas is filled and the air pressure in the vacuum ingot pulling furnace is controlled to be 5000Pa~6000Pa. The present invention adopts high-purity argon as a protective gas to prevent oxidation, reduce impurities in the high-entropy alloy bar, and at the same time ensure the performance of the high-entropy alloy bar, and control the oxygen content of the high-entropy alloy bar by controlling the vacuum degree to prevent the mechanical properties of the high-entropy alloy bar from being reduced. By controlling the air pressure in the vacuum ingot pulling furnace, it is prevented that when the air pressure is high, the melt is easily disturbed by the gas, resulting in instability of the molten pool, which may cause defects such as bubbles and inclusions in the alloy, and when the air pressure is low, the gas support effect is insufficient, which may cause instability of the melt, sinking or deviation, and affect the uniformity of smelting.

[0012] The above method is characterized in that the smelting power in step 4 is 140kW~280kW, and the stable molten pool is maintained for more than 3 minutes. The present invention controls the smelting parameters to ensure that the metal raw materials are fully melted, a stable molten pool is formed, and the components are evenly mixed, so as to prevent the low smelting power from making it difficult to melt the added metal raw materials and the high smelting power from making the low melting point metal raw material elements easily volatilize, thereby affecting the deficiency of component uniformity.

[0013] The above method is characterized in that the ingot pulling speed in step 5 is 0.3mm / min~2.5mm / min, and the speed of reducing the smelting power is 1.8kW / min~15kW / min. The present invention improves the efficiency of ingot pulling while ensuring the ingot pulling effect by controlling the ingot pulling speed, preventing the ingot pulling efficiency from being affected by a low ingot pulling speed and the ingot pulling rate from being easily leaked due to a high ingot pulling rate, thereby affecting the deficiencies in the formability of the final bar. The solidification of the alloy is facilitated by controlling the speed of reducing the smelting power, while preventing the ingot pulling speed from being too slow, which makes it difficult for the alloy to solidify, and the ingot pulling speed from being too fast, which causes the alloy to solidify in the crucible, which is not conducive to forming.

[0014] The above method is characterized in that the smelting power in the step of increasing the smelting power in step 6 does not exceed 280kW, and the stable molten pool is maintained for more than 3 minutes after it is formed again. The present invention prevents the volatilization of alloy elements by controlling the subsequent smelting power, ensures the accuracy of the alloy element content, and ensures that a stable molten pool is formed and the components are evenly mixed by maintaining the stable molten pool for more than 3 minutes after it is formed again.

[0015] Compared with the prior art, the present invention has the following advantages: 1. The present invention divides the mixed material into batches and melts them sequentially, i.e., intermittent feeding, thereby ensuring the uniformity of chemical composition, avoiding the pre-treatment process flow and mechanical processing flow of subsequent smelting, and reducing the invisible loss of raw materials. In the process of batch smelting, ingots are pulled in batches to ensure that there is always liquid metal shrinkage at the solid-liquid interface, avoiding the generation of shrinkage defects, thereby improving the yield rate of high-entropy alloy bars, and preparing high-quality high-entropy alloy bars with uniform chemical composition and no obvious casting defects, greatly reducing processing costs, saving raw materials, and improving material utilization. It has the characteristics of high efficiency, high yield rate, low loss, and low energy consumption, is economical and environmentally friendly, improves quality and efficiency, and the process route of the present invention is short, saves procedures and time, reduces comprehensive costs, has significant economic benefits, and is conducive to industrial promotion and use.

[0016] 2. The present invention stops pulling the ingot and feeding the next material when the liquid level of the stable molten pool is controlled to drop to 1 / 2 to 1 / 3 of the original liquid level, thereby ensuring the efficiency of alloy melting and the stability of the liquid level, preventing the ingot pulling efficiency from being affected by an excessively high liquid level and the splashing of liquid caused by adding material when the liquid level is too low, thereby ensuring the uniformity of the ingot pulling. The prepared high-entropy alloy bar does not require subsequent hot extrusion forming, and high-entropy alloy components that are difficult to process at high temperatures can be prepared, thereby broadening the preparation range of high-entropy alloy bars, and obtaining high-entropy alloy bars with uniform composition and no shrinkage cavities.

[0017] 3. The present invention controls the number of batches, controls the quality of the stable molten pool and the pulled ingot formed in each smelting, ensures the efficiency of the melting of the metal raw materials and the stability of the liquid level of the molten pool by carrying out the smelting in batches, and prevents the instability of the molten pool and uneven ingot pulling caused by adding too much metal raw material at one time.

[0018] 4. The present invention improves the efficiency of ingot pulling while ensuring the ingot pulling effect by controlling the ingot pulling speed, and prevents the ingot pulling efficiency from being affected by a low ingot pulling speed, and the formability of the final bar from being affected by a high ingot pulling speed. The alloy is easily solidified by controlling the speed of reducing the melting power, and at the same time, the alloy is not easily solidified by reducing the melting power too slowly, and the alloy is not easily solidified in the crucible due to reducing the melting power too quickly, which is not conducive to forming.

[0019] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a physical picture of the high entropy alloy rod prepared in Example 1 of the present invention.

[0021] Figure 2 This is the EBSD microstructure image of the high entropy alloy rod prepared in Example 1 of the present invention.

[0022] Figure 3 This is the EBSD microstructure image of the high entropy alloy rod prepared in Example 2 of the present invention.

[0023] Figure 4 X-ray diffraction patterns of high entropy alloy bars prepared in Examples 1, 2, and 3 of the present invention. DETAILED DESCRIPTION

[0024] Example 1 This implementation includes the following steps: Step 1: Press Co 1.75 CrFeNiAl 0.1 Ti 0.15 Weighing metal raw materials with a mass purity greater than 99.5%, wherein Co, Cr, Fe, Ni, Al, and Ti are all in granular form, then grinding the surface of the metal raw materials, and then ultrasonically cleaning and vacuum drying to obtain clean metal raw materials, while cleaning the water-cooled copper crucible in the vacuum ingot pulling furnace; Step 2: Mix the clean metal raw materials obtained in step 1 to obtain a mixture, and then divide the mixture into five batches. Then, directly put the first batch of the mixture into the water-cooled copper crucible in the vacuum ingot pulling furnace cleaned in step 1, and put the remaining batches of the mixture into the feeder in sequence; Step 3: Install the vacuum ingot pulling furnace containing the first batch of mixed materials in step 2 with Co1.75 CrFeNiAl 0.1 Ti 0.15 The ingot is made of alloy, and then the vacuum in the vacuum ingot furnace is evacuated to 5×10 -3 Pa, and then fill with high-purity argon gas with a mass purity greater than 99.9% and control the gas pressure in the vacuum ingot pulling furnace to be 5000Pa~6000Pa, to obtain a vacuum ingot pulling furnace to be smelted; Step 4: Turn on the power of the vacuum ingot pulling furnace to be smelted obtained in step 3, control the smelting power to 280 kW, melt the first batch of clean metal raw materials in the water-cooled copper crucible completely, form a stable molten pool in the vacuum ingot pulling furnace and maintain it for 3 minutes; Step 5, turning on the ingot pulling switch of the vacuum ingot pulling furnace that forms the stable molten pool in step 4, controlling the ingot pulling speed to 2 mm / min, pulling the ingot and simultaneously reducing the smelting power at a speed of 12 kW / min; Step 6: When the liquid level of the stable molten pool in step 5 drops to 1 / 3 of the original liquid level, turn off the ingot pulling switch, wait for its speed to return to zero, turn on the feeder in step 2 to feed the second batch of mixed materials, then increase the smelting power to 280kW, and form a stable molten pool again and maintain it for 3 minutes; Step 7, repeating steps 5 and 6 until all batches of mixed materials are put in and the ingots are drawn, and a high entropy alloy billet is obtained after cooling; Step 8: The high entropy alloy rod blank obtained in step 7 is subjected to surface peeling treatment to obtain a high entropy alloy rod with uniform composition and no shrinkage cavities.

[0025] The high entropy alloy rod prepared in this embodiment was subjected to ICP composition analysis, and the results are shown in Table 1. It can be seen from Table 1 that the high entropy alloy rod prepared in this embodiment has uniform composition and no macro segregation phenomenon.

[0026] Table 1

[0027] Figure 1 This is a physical picture of the high entropy alloy bar prepared in this embodiment. Figure 1 It can be seen that the high entropy alloy bar prepared in this embodiment has a good appearance and no obvious casting defects.

[0028] Figure 2 This is a microstructure photo of the high entropy alloy bar prepared in Example 1 of the present invention. Figure 2 It can be seen that the high entropy alloy rod prepared in this embodiment has a random grain orientation and a relatively large grain size. The random grain orientation can ensure that the alloy is isotropic, so that the alloy has the same mechanical properties in all directions. The relatively large grains are caused by the relatively slow cooling rate of the alloy during the solidification process.

[0029] Example 2 This implementation includes the following steps: Step 1: Press Co 0.5 Cr 1.2 Fe1Ni2Al 0.5 Ti 0.3 Weighing metal raw materials with a purity greater than 99.9%, wherein Co, Cr, Fe, Ni, Al, and Ti are all in granular form, then grinding the surface of the metal raw materials, and then ultrasonically cleaning and vacuum drying to obtain clean metal raw materials, while cleaning the water-cooled copper crucible in the vacuum ingot pulling furnace; Step 2: Mix the clean metal raw materials obtained in step 1 to obtain a mixture, and then divide the mixture into three batches. Then, directly put the first batch of the mixture into the water-cooled copper crucible in the vacuum ingot pulling furnace cleaned in step 1, and put the remaining batches of the mixture into the feeder in sequence; Step 3: Install the vacuum ingot pulling furnace containing the first batch of mixed materials in step 2 with Co 0.5 Cr 1.2 Fe1Ni2Al 0.5 Ti 0.3 The ingot is made of alloy, and then the vacuum in the vacuum ingot furnace is evacuated to 4×10 -3 Pa, and then fill with high-purity argon gas with a mass purity greater than 99.9% and control the gas pressure in the vacuum ingot pulling furnace to be 5000Pa~6000Pa, to obtain a vacuum ingot pulling furnace to be smelted; Step 4: Turn on the power of the vacuum ingot pulling furnace to be smelted obtained in step 3, control the smelting power to 250 kW, melt the first batch of clean metal raw materials in the water-cooled copper crucible completely, form a stable molten pool in the vacuum ingot pulling furnace and maintain it for 5 minutes; Step 5, turning on the ingot pulling switch of the vacuum ingot pulling furnace that forms the stable molten pool in step 4, controlling the ingot pulling speed to 0.3 mm / min, pulling the ingot and simultaneously reducing the smelting power at a speed of 1.8 kW / min; Step 6: When the liquid level of the stable molten pool in step 5 drops to 1 / 3 of the original liquid level, turn off the ingot pulling switch, wait for its speed to return to zero, turn on the feeder in step 2 to feed the second batch of mixed materials, then increase the smelting power to 250kW, and form a stable molten pool again and maintain it for 5 minutes; Step 7, repeating steps 5 and 6 until all batches of mixed materials are put in and the ingots are drawn, and a high entropy alloy billet is obtained after cooling; Step 8: The high entropy alloy rod blank obtained in step 7 is subjected to surface peeling treatment to obtain a high entropy alloy rod with uniform composition and no shrinkage cavities.

[0030] Figure 3This is a microstructure photo of the high entropy alloy bar prepared in this example. Figure 3 It can be seen that the high entropy alloy bar prepared in this embodiment has a random grain orientation and a relatively coarse grain size.

[0031] After testing, the high entropy alloy bar prepared in this embodiment has a good appearance, no obvious casting defects, uniform composition, and no shrinkage cavities.

[0032] Example 3 This implementation includes the following steps: Step 1: Press Co 2.2 Cr 0.9 Fe 1.4 Ni 2.1 Al 0.3 Ti 0.8 Weighing metal raw materials with a mass purity greater than 99.95%, wherein Co, Cr, Fe, Ni, and Al are all in granular form, and Ti is in titanium sponge form, then grinding the surface of the metal raw materials, and then ultrasonically cleaning and vacuum drying to obtain clean metal raw materials, and at the same time cleaning the water-cooled copper crucible in the vacuum ingot pulling furnace; Step 2: Mix the clean metal raw materials obtained in step 1 to obtain a mixture, and then divide the mixture into five batches. Then, directly put the first batch of the mixture into the water-cooled copper crucible in the vacuum ingot pulling furnace cleaned in step 1, and put the remaining batches of the mixture into the feeder in sequence; Step 3: Install the vacuum ingot pulling furnace containing the first batch of mixed materials in step 2 with Co 2.2 Cr 0.9 Fe 1.4 Ni 2.1 Al 0.3 Ti 0.8 The ingot is made of alloy, and then the vacuum in the vacuum ingot furnace is evacuated to 3×10 - 3 Pa, and then fill with high-purity argon gas with a mass purity greater than 99.9% and control the gas pressure in the vacuum ingot pulling furnace to be 5000Pa~6000Pa, to obtain a vacuum ingot pulling furnace to be smelted; Step 4: Turn on the power of the vacuum ingot pulling furnace to be smelted obtained in step 3, control the smelting power to 140 kW, melt the first batch of clean metal raw materials in the water-cooled copper crucible completely, form a stable molten pool in the vacuum ingot pulling furnace and maintain it for 4 minutes; Step 5, turn on the ingot pulling switch of the vacuum ingot pulling furnace that forms a stable molten pool in step 4, control the ingot pulling speed to 2.5 mm / min, pull the ingot and simultaneously reduce the smelting power at a speed of 15 kW / min; Step 6: When the liquid level of the stable molten pool in step 5 drops to 1 / 2 of the original liquid level, turn off the ingot pulling switch, wait for its speed to return to zero, turn on the feeder in step 2 to feed the second batch of mixed materials, then increase the smelting power to 180kW, and form a stable molten pool again and maintain it for 5 minutes; Step 7, repeating steps 5 and 6 until all batches of mixed materials are put in and the ingots are drawn, and a high entropy alloy billet is obtained after cooling; Step 8: The high entropy alloy rod blank obtained in step 7 is subjected to surface peeling treatment to obtain a high entropy alloy rod with uniform composition and no shrinkage cavities.

[0033] After testing, the high entropy alloy bar prepared in this embodiment has a good appearance, no obvious casting defects, uniform composition, and no shrinkage cavities.

[0034] Figure 4 The X-ray diffraction diagram of the high entropy alloy rod prepared in Examples 1, 2 and 3 of the present invention is shown in FIG. Figure 4 It can be seen that the phase structure of the high entropy alloys prepared in Examples 1, 2, and 3 is a single FCC structure, no other obvious diffraction peaks are observed, the alloy does not have any second phase, and is a single-phase structure material.

[0035] Example 4 This implementation includes the following steps: Step 1: Press Co 1.5 Cr 1.1 Fe 0.8 Ni 1.5 Al 0.4 Ti 0.4 Weighing metal raw materials with a purity greater than 99.9%, wherein Co, Cr, Fe, Ni, Al, and Ti are all in granular form, then grinding the surface of the metal raw materials, and then ultrasonically cleaning and vacuum drying to obtain clean metal raw materials, while cleaning the water-cooled copper crucible in the vacuum ingot pulling furnace; Step 2: Mix the clean metal raw materials obtained in step 1 to obtain a mixture, and then divide the mixture into five batches. Then, directly put the first batch of the mixture into the water-cooled copper crucible in the vacuum ingot pulling furnace cleaned in step 1, and put the remaining batches of the mixture into the feeder in sequence; Step 3: Install the vacuum ingot pulling furnace containing the first batch of mixed materials in step 2 with Co 1.5 Cr 1.1 Fe 0.8 Ni 1.5 Al 0.4 Ti 0.4 The ingot is made of alloy, and then the vacuum in the vacuum ingot furnace is evacuated to 7×10 - 3Pa, and then fill with high-purity argon gas with a mass purity greater than 99.9% and control the gas pressure in the vacuum ingot pulling furnace to be 5000Pa~6000Pa, to obtain a vacuum ingot pulling furnace to be smelted; Step 4: Turn on the power of the vacuum ingot pulling furnace to be smelted obtained in step 3, control the smelting power to 200 kW, melt the first batch of clean metal raw materials in the water-cooled copper crucible completely, form a stable molten pool in the vacuum ingot pulling furnace and maintain it for 4 minutes; Step 5, turning on the ingot pulling switch of the vacuum ingot pulling furnace that forms the stable molten pool in step 4, controlling the ingot pulling speed to 1.5 mm / min, pulling the ingot and simultaneously reducing the smelting power at a speed of 9 kW / min; Step 6: When the liquid level of the stable molten pool in step 5 drops to 2 / 5 of the original liquid level, turn off the ingot pulling switch, wait until its speed returns to zero, turn on the feeder in step 2 to feed the second batch of mixed materials, then increase the smelting power to 220kW, and form a stable molten pool again and maintain it for 5 minutes; Step 7, repeating steps 5 and 6 until all batches of mixed materials are put in and the ingots are drawn, and a high entropy alloy billet is obtained after cooling; Step 8: The high entropy alloy rod blank obtained in step 7 is subjected to surface peeling treatment to obtain a high entropy alloy rod with uniform composition and no shrinkage cavities.

[0036] After testing, the high entropy alloy bar prepared in this embodiment has a good appearance, no obvious casting defects, uniform composition, and no shrinkage cavities.

[0037] Example 5 This implementation includes the following steps: Step 1: Press Co2Cr 1.1 Fe 1.4 Ni 1.2 Al 0.5 Ti 0.1 Weighing metal raw materials with a mass purity greater than 99.7%, wherein Co, Cr, Fe, Ni, and Al are all in granular form, and Ti is in titanium sponge form, then grinding the surface of the metal raw materials, and then ultrasonically cleaning and vacuum drying to obtain clean metal raw materials, and at the same time cleaning the water-cooled copper crucible in the vacuum ingot pulling furnace; Step 2: Mix the clean metal raw materials obtained in step 1 to obtain a mixture, and then divide the mixture into eight batches. Then, directly put the first batch of the mixture into the water-cooled copper crucible in the vacuum ingot pulling furnace cleaned in step 1, and put the remaining batches of the mixture into the feeder in sequence; Step 3: Install the Co2Cr 1.1 Fe 1.4 Ni 1.2 Al 0.5 Ti0.1 The ingot is made of alloy, and then the vacuum in the vacuum ingot furnace is evacuated to 3×10 -3 Pa, and then fill with high-purity argon gas with a mass purity greater than 99.9% and control the gas pressure in the vacuum ingot pulling furnace to be 5000Pa~6000Pa, to obtain a vacuum ingot pulling furnace to be smelted; Step 4: Turn on the power of the vacuum ingot pulling furnace to be smelted obtained in step 3, control the smelting power to 180 kW, melt the first batch of clean metal raw materials in the water-cooled copper crucible completely, form a stable molten pool in the vacuum ingot pulling furnace and maintain it for 3.5 minutes; Step 5, turn on the ingot pulling switch of the vacuum ingot pulling furnace that forms a stable molten pool in step 4, control the ingot pulling speed to 2.5 mm / min, pull the ingot and simultaneously reduce the smelting power at a speed of 15 kW / min; Step 6: When the liquid level of the stable molten pool in step 5 drops to 1 / 2 of the original liquid level, turn off the ingot pulling switch, wait for its speed to return to zero, turn on the feeder in step 2 to feed the second batch of mixed materials, then increase the smelting power to 220kW, and form a stable molten pool again and maintain it for 4 minutes; Step 7, repeating steps 5 and 6 until all batches of mixed materials are put in and the ingots are drawn, and a high entropy alloy billet is obtained after cooling; Step 8: The high entropy alloy rod blank obtained in step 7 is subjected to surface peeling treatment to obtain a high entropy alloy rod with uniform composition and no shrinkage cavities.

[0038] After testing, the high entropy alloy bar prepared in this embodiment has a good appearance, no obvious casting defects, uniform composition, and no shrinkage cavities.

[0039] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent change made to the above embodiment according to the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing a high entropy alloy bar with uniform composition and no shrinkage cavity, It is characterized in that The method combines intermittent feeding with ingot pulling process to obtain high entropy alloy rods with uniform composition and no shrinkage defects.

2. The method for preparing a high entropy alloy bar with uniform composition and no shrinkage cavity according to claim 1, It is characterized in that The method comprises the following steps: Step 1: Grind the surface of the metal raw material, then perform ultrasonic cleaning and vacuum drying to obtain clean metal raw material, and clean the water-cooled copper crucible in the vacuum ingot pulling furnace; Step 2: Mix the clean metal raw materials obtained in step 1 to obtain a mixture, and then divide the mixture into batches. Then, the first batch of the mixture is directly placed in the water-cooled copper crucible in the vacuum ingot pulling furnace cleaned in step 1, and the remaining batches of the mixture are placed in the feeder in sequence; Step 3, installing the ingot in the vacuum ingot pulling furnace loaded with the first batch of mixed materials in step 2, and then evacuating the vacuum ingot pulling furnace, and then filling it with inert gas to obtain a vacuum ingot pulling furnace to be smelted; Step 4: Turn on the power of the vacuum ingot pulling furnace to be smelted obtained in step 3, control the smelting power, and completely melt the first batch of clean metal raw materials in the water-cooled copper crucible to form a stable molten pool in the vacuum ingot pulling furnace; Step 5, turning on the ingot pulling switch of the vacuum ingot pulling furnace that forms the stable molten pool in step 4, pulling the ingot and simultaneously reducing the smelting power; Step 6: When the liquid level of the stable molten pool in step 5 drops to 1 / 2 to 1 / 3 of the original liquid level, turn off the ingot pulling switch, wait for its speed to return to zero, turn on the feeder in step 2 to feed the second batch of mixed materials, then increase the smelting power, and form a stable molten pool again; Step 7, repeating steps 5 and 6 until all batches of mixed materials are put in and the ingots are drawn, and a high entropy alloy billet is obtained after cooling; Step 8: The high entropy alloy rod blank obtained in step 7 is subjected to surface peeling treatment to obtain a high entropy alloy rod with uniform composition and no shrinkage cavities.

3. The method according to claim 2, It is characterized in that The metal raw material in step 1 is Co, Cr, Fe, Ni, Al, or Ti metal particles, the mass purity of the metal raw material is greater than 99.5%, and the particle size is no greater than 10 mm.

4. The method according to claim 2, It is characterized in that The batching described in step 2 is divided into 3 to 8 batches, and the composition of the mixed material in each batch is consistent.

5. The method according to claim 2, It is characterized in that The composition of the starter in step three is consistent with the composition of the mixed material in step two.

6. The method according to claim 2, It is characterized in that The vacuuming in step 3 is to evacuate to a vacuum degree not greater than 7×10 -3 Pa, the inert gas is high-purity argon with a mass purity greater than 99.9%, and the inert gas is filled and the gas pressure in the vacuum ingot pulling furnace is controlled to be 5000Pa~6000Pa.

7. The method according to claim 2, It is characterized in that The smelting power in step 4 is 140kW~280kW, and the stable molten pool is maintained for more than 3 minutes after being formed.

8. The method according to claim 2, It is characterized in that In step 5, the ingot pulling speed is 0.3 mm / min to 2.5 mm / min, and the speed of reducing the smelting power is 1.8 kW / min to 15 kW / min.

9. The method according to claim 2, It is characterized in that In step 6, the smelting power is increased so that it does not exceed 280 kW, and the stable molten pool is formed again and maintained for more than 3 minutes.

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