A method for preparing a high-entropy alloy directionally solidified component

Abstract

The present application relates to the alloy manufacturing technical field, more specifically, it relates to a kind of preparation method of high-entropy alloy directional solidification component.The preparation method of high-entropy alloy directional solidification component of the present application includes: (1) the raw material powder of preparation high-entropy alloy directional solidification component is mixed, and mixed material is obtained, and the mixed material is placed into mould;(2) directional solidification, and high-entropy alloy directional solidification component is obtained.Compared with prior art, the preparation method of the present application greatly shortens directional solidification process flow, shortens manufacturing cycle, reduces energy consumption, and the uniformity of the directional solidification component prepared is good.

Description

Technical Field

[0001] This invention relates to the field of alloy manufacturing technology, and more specifically, to a method for preparing a high-entropy alloy directional solidification component. Background Technology

[0002] High-entropy alloys are a disruptive new alloy system developed in recent years. They are composed of five or more principal elements, mixed in equiatomic or near-equiatomic ratios, with each principal element comprising 5% to 35% of the total atomic mass. Therefore, they are also known as multi-principal-element, equiatomic, or near-equiatomic alloys. Compared to traditional alloys, high-entropy alloys exhibit a high-entropy effect thermodynamically, a slow diffusion effect kinetically, a lattice distortion effect structurally, and a cocktail effect in terms of performance. Under the coupled effect of these multiple mechanisms, high-entropy alloys possess many superior properties unmatched by traditional materials, and are thus considered one of the key materials that hold the promise of solving current bottlenecks in material performance in engineering fields.

[0003] Directional solidification technology enables solidified structures to grow along specific directions, eliminating transverse grain boundaries and thus further improving the mechanical properties of high-entropy alloys in those directions. Common directional solidification methods include the Bridgman method, optical suspension method, electromagnetic confinement forming method, and electromagnetic cold crucible method. Among these, the Bridgman method has relatively simple equipment, is easy to operate, and has low cost. It is also the easiest method to prepare large-sized samples, making it one of the most widely used methods in the industrial field for preparing complex directional solidification components. However, high-entropy alloys have many principal components, and the density and melting point of each element vary greatly. During the melting of the directional solidification master alloy ingot, the raw materials cannot be simultaneously in a molten state and uniformly mixed, leading to elemental segregation in the master alloy ingot and resulting in poor compositional uniformity of the directional solidification component. To obtain a master alloy ingot with relatively uniform composition, a multi-melting method is generally used, resulting in multiple processes. Taking vacuum induction melting (VISM), which involves relatively few steps, as an example, the melting of high-entropy alloy ingots requires six steps: batching calculation, weighing, material distribution, primary melting, secondary melting, and processing into bars of suitable size. If directional solidification of components is required, three more steps are needed: induction melting of the bars, pouring of molten metal into a heat-holding mold, and directional solidification of the mold, totaling nine steps. It is evident that traditional methods for preparing directional solidified high-entropy alloy components suffer from poor compositional uniformity, complex processes, long flow rates, long cycles, and high energy consumption. Therefore, the development of new methods for directional solidification of high-entropy alloy components with high homogeneity, short flow rates, and low energy consumption has attracted considerable attention. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a method for preparing a high-entropy alloy directional solidification component. The method of the present invention significantly shortens the directional solidification process, shortens the manufacturing cycle, reduces energy consumption, and at the same time produces a solidified component with good uniformity.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for preparing a high-entropy alloy directional solidification component, comprising:

[0007] (1) Mix the raw material powder for preparing high-entropy alloy directional solidification components to obtain a mixture, and place the mixture into a casting mold;

[0008] (2) Directional solidification to obtain high-entropy alloy directional solidified components.

[0009] In this invention, the raw materials for preparing the high-entropy alloy directional solidification component include pure metal powder and / or alloy powder; preferably one or more of pure Fe powder, pure Co powder, pure Ni powder, pure Al powder, NiTi alloy powder, AlV55 alloy powder, and NiCr50 alloy powder.

[0010] The particle size of the raw material powder is 30–53 μm;

[0011] The purity of the pure metal powder is ≥99.5%, and the impurity content of the alloy powder is ≤0.5%.

[0012] The raw materials used in the preparation of directional solidification components according to the present invention also include non-metallic powders.

[0013] The melting point of the raw material powders in this invention is lower than the highest temperature that can be achieved by directional furnace heating.

[0014] The present invention does not impose any special limitations on the directional solidification, and conventional methods in the art can be used.

[0015] In this invention, step (2) specifically includes:

[0016] The raw material powder is heated to melt, held at that temperature, and then the mold is moved in a directional manner. While the mold is moving in a directional manner, it is cooled and removed to obtain a high-entropy alloy directional solidification component. Preferably, the raw material powder is heated to its melting temperature; more preferably, it is heated to 0-100°C above the melting point of the raw material; even more preferably, it is heated to 1600-1650°C.

[0017] In this invention, the speed of the directional movement is 0.05 to 0.2 mm / s; the heat preservation time is 10 to 30 min, preferably 25 to 30 min; the cooling is preferably performed using liquid metal; the temperature of the liquid metal is 20 to 30°C; and the liquid metal is preferably a gallium indium tin alloy.

[0018] In one embodiment of the present invention, the method of directional solidification is preferably:

[0019] The mold is placed on the base of the Bridgeman directional furnace and held at 0–100°C above the melting point of the high-entropy alloy under vacuum or inert gas conditions until the powder filling the mold is completely melted. The holding time is then extended to 0–30 minutes. The pulling device is then activated at a moving speed of 0.001–2 mm / s to allow the base to move vertically downwards, bringing the bottom of the mold into contact with the liquid metal. After the directional movement is activated, the mold gradually enters the liquid metal and solidifies. The preferred moving speed is 0.05–0.1 mm / s.

[0020] In this invention, before mixing the raw material powder, the proportioning is calculated based on the high-entropy alloy composition requirements and the component content of each material;

[0021] The content of non-burn-off elements in the formulation is obtained directly from their weight percentage. However, for high vapor pressure volatilization burn-off elements, a certain compensation amount needs to be added when calculating the ingredients. This compensation amount depends on the total weight of the ingredients and the weight percentage of the burn-off elements. An initial value is set based on experience, and the final value is determined through sample testing.

[0022] The preferred method for mixing is ball milling;

[0023] The ball mill has a ball-to-powder ratio of 5:1 to 10:1, a rotation speed of 300 to 1200 rad / min, and a milling time of 1 to 3 hours; ball milling can make the prepared powder uniformly mixed.

[0024] The ball milling is preferably carried out under the protection of an inert gas, which is argon.

[0025] The preparation method of the present invention further includes: densifying the mixture while it is being placed into the mold;

[0026] The densification process is compaction or vibration compaction, preferably vibration compaction;

[0027] The frequency of the vibration is 20-50 Hz, preferably 25 Hz, and the vibration time is 15-60 min, preferably 30 min.

[0028] The preparation method of the present invention further includes: after the mixture is placed into the mold, before the directional solidification, adding a compensation amount of raw material powder; setting a feeding port at the top of the mold, and filling the feeding port with powder during the powder filling process, and forming liquid metal after the powder melts; the existence of the feeding port provides pressure for the liquid metal to fill the mold on the one hand, and on the other hand, it serves to compensate for the volume shrinkage during the solid-liquid transformation of the liquid metal; the end of powder filling is marked by the filling port being filled with powder after compaction.

[0029] To better achieve the feeding of liquid metal, the feeding port should be designed as an inverted frustum or inverted trapezoid, and the area of ​​the feeding port at the contact point with the component should not be less than the area of ​​the component.

[0030] In this invention, the compensation amount of the raw material powder is calculated according to Formula 1;

[0031] V r =k·V m (ρ HEA / ρ-1) Formula 1;

[0032] Among them, V r V represents the volume of the feed inlet (compensation amount). m Let ρ be the volume of the component. HEA ρ is the theoretical density of the high-entropy alloy, ρ is the tap density of the powder, and k is the compensation coefficient. The initial value is set based on experience, and the final value is determined through experiments. 1.0≤k≤1.5.

[0033] This invention does not have special requirements for the casting mold, but a ceramic casting mold is preferred.

[0034] In one embodiment of the present invention, a ceramic mold is prepared by wax molding, coating, dewaxing, and firing, and the raw material powder is placed into the ceramic mold.

[0035] In this invention, the directional solidification is carried out under vacuum conditions or in the presence of an inert gas; the inert gas is argon; the vacuum degree of the directional solidification is ≤10. -1 Pa.

[0036] The method for preparing high-entropy alloy directional solidification components of the present invention further includes: after cooling, taking the solidified component out of the directional furnace, removing the mold, separating the feed port and the component body, and removing impurities from the surface of the solidified component;

[0037] Preferably, the directional solidification component is placed in an alkaline washing tank to remove surface dirt;

[0038] Manual sand blowing is the preferred method for removing the mold.

[0039] The high-entropy alloy directional solidification component of the present invention may be composed of FeCoNi2Al, AlCrFeNi2Ti, Fe3Co3Ni3AlVTi, or AlCoCrFeNi 2.1 .

[0040] The method for preparing high-entropy alloy directional solidification components of the present invention has the following significant advantages compared with existing domestic technologies:

[0041] 1. This invention uses powder as raw material, avoiding the melting step of the master alloy ingot, and shortens the manufacturing process of high-entropy alloy directional solidification components from 9 steps to 5 steps, which greatly shortens the high-entropy alloy directional solidification process and manufacturing cycle, and reduces the energy consumption of production.

[0042] 2. The high-entropy alloy directional solidification components manufactured using the method of this invention have good compositional uniformity and high compositional accuracy (if conventional master alloy ingot smelting methods are used, a large amount of elements may be burned off, causing deviations between the prepared alloy composition and the batch composition), and also have better uniformity.

[0043] 3. Applicable to the preparation of high-entropy alloy directional solidification components of various systems and specific shapes;

[0044] 4. It avoids the scouring of the mold when molten metal is poured into the mold during the traditional process, reducing the risk of high-density inclusions and surface reactive defects. Therefore, the high-entropy alloy directional solidification components prepared have high metallurgical quality and good performance. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the casting mold for the cylindrical component manufactured according to Embodiment 1 of the present invention, wherein 1 is the material filling port and 2 is the cylindrical component;

[0046] Figure 2 The results are X-ray inspection results of the cylindrical component manufactured in Embodiment 1 of the present invention;

[0047] Figure 3 This is a SEM image of the surface reaction layer of the cylindrical component manufactured in Embodiment 1 of the present invention;

[0048] Figure 4 The tensile curve of the cylindrical component manufactured in Embodiment 1 of the present invention;

[0049] Figure 5 This is a schematic diagram of the casting mold for the blade-like component manufactured in Embodiment 5 of the present invention, wherein 1 is the feeding port, 2 is the tenon, 3 is the blade body, and 4 is the blade crown. Detailed Implementation

[0050] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0051] To further illustrate the present invention, the following embodiments are provided for detailed description. All raw materials used in the following embodiments of the present invention are commercially available products.

[0052] Example 1:

[0053] The manufacturing process of a high-entropy alloy directional solidification cylindrical component with a nominal composition of FeCoNi2Al, the cylindrical component having dimensions of... Its preparation method includes the following steps:

[0054] 1. Raw materials: Pure Fe powder, pure Co powder, pure Ni powder, and pure Al powder are used as raw materials. The powder particle size is 30-53μm and the powder purity is ≥99.5%. The melting point of the selected powders is lower than the highest temperature that can be achieved by directional furnace heating (the highest temperature of directional furnace is generally 1700-2000℃).

[0055] 2. The manufacturing process of high-entropy alloy directional solidification components includes the following 5 steps:

[0056] (1) Batching calculation: The batching calculation was carried out based on the FeCoNi2Al high-entropy alloy composition according to the atomic ratio of Fe 20%, Co 20%, Ni 40%, and Al 20%. Among them, the formula contents of non-burning elements Fe, Co, and Ni were directly obtained based on their weight percentages. However, Al, a high vapor pressure volatilization burn-off element, needed to be compensated for during the batching calculation. Based on the total weight of the batching and the weight percentage of Al, combined with sample tests, the final Al content was determined to be increased by 5% on the basis of the calculation.

[0057] (2) Weighing: Based on the ingredient calculation results, weigh Fe powder, Co powder, Ni powder and Al powder to 215g, 227g, 453g and 109g respectively, and then dry them after preliminary mixing.

[0058] (3) Ball milling: The prepared powder is placed in a ball mill jar in an argon-protected glove box. The grinding balls are made of corundum and the grinding jar is made of stainless steel. The ball-to-powder ratio is 5:1. Argon gas is also used to protect the grinding jar. A planetary ball mill is used with a rotation speed of 600 rad / min and a ball milling time of 1 hour to make the powder mix evenly and grind each other.

[0059] (4) Powder loading: After wax molding, coating, dewaxing, and firing, a ceramic mold required for directional solidification is obtained, and the ball-milled raw material powder is loaded into the mold.

[0060] During the powder loading process, the powder loading and compaction are carried out simultaneously. The mold is always placed on the vibration platform to achieve the purpose of compacting the powder. The vibration frequency of the vibration platform is 25Hz and the vibration time is 30min. In addition, an inverted frustum-shaped feeding port is set at the top of the mold. After the powder melts, it forms a molten metal. The presence of the feeding port provides pressure for the molten metal to fill the mold and also compensates for the volume shrinkage during the solid-liquid transition of the molten metal. The powder loading is completed when the feeding port is full of powder after compaction.

[0061] The design of the feed inlet size is calculated based on the component mold volume and powder compaction density, and a certain compensation amount is set. The specific calculation formula is: V r =k·V m (ρ HEA / ρ-1), where V r V represents the volume of the feed inlet. m Let ρ be the volume of the component. HEA ρ is the theoretical density of the high-entropy alloy, ρ is the powder tap density, and k is the compensation coefficient. Initial values ​​are set based on experience, and the final values ​​are determined experimentally. In this embodiment, V... m The value is 7.85cm 3 , ρ HEA The value is 7.44 g / cm³ 3 The ρ value is 4.4 g / cm³. 3 The value of k is 1.2, and the calculated volume of the feed inlet V is... r It should be 6.51cm 3 .

[0062] (5) Directional solidification: Place the mold on the Bridgeman directional furnace base and turn on the vacuum pump to make the vacuum level inside the equipment ≤10. -1 Pa, maintaining a vacuum, and holding at 1600–1650℃ until the powder filling the mold is completely melted, then holding for another 25 minutes, the pulling device is activated at a moving speed of 0.1 mm / s to initiate directional stretching, causing the base to move vertically from top to bottom. The bottom of the mold comes into contact with the liquid gallium indium tin alloy coolant. Directional stretching causes the mold to gradually enter the liquid gallium indium tin alloy coolant for solidification (the coolant's operating temperature is room temperature), thus obtaining a high-entropy alloy directional solidified cylindrical component of FeCoNi2Al with a directional solidification structure, such as... Figure 1 As shown, 1 is the feeding port and 2 is the cylindrical component.

[0063] 3. Remove the high-entropy alloy component after directional solidification from the directional furnace, remove the mold by manual sandblasting, and then separate the feed port and the component body by wire cutting; place the component in an alkaline washing tank to wash away surface dirt.

[0064] X-ray inspection was used to inspect the internal metallurgical quality of the component. Samples were taken from the upper, middle, and lower parts of the component, with the side closest to the feed inlet considered the upper part, to determine the ingot composition. Samples were cut from the near-surface area of ​​the component, and metallographic analysis was used to determine the surface contamination layer of the prepared directional solidified component. The component was then sectioned, and mechanical property test specimens were fabricated to test the mechanical properties of the prepared high-entropy alloy directional solidified component. The X-ray inspection results are as follows: Figure 2As shown, the FeCoNi2Al high-entropy alloy directional solidification component of this embodiment exhibits good internal metallurgical quality, with no inclusions or defects; chemical composition analysis shows uniform composition at different locations within the component; and SEM (scanning electron microscopy) observations yield the following results. Figure 3 As shown, the surface contaminant layer thickness is less than 10 μm; the results of the standard tensile property test (HB 5143-1996) are as follows. Figure 4 As shown, the room temperature tensile strength of the FeCoNi2Al high-entropy alloy directional solidification component of this embodiment is 1005-1120 MPa, and the elongation is 4.5%-6.1%, which has excellent comprehensive strength and toughness. Table 1 is a composition diagram (wt%) of the cylindrical component manufactured in Example 1 of this invention at different positions, which shows that the component has high composition uniformity.

[0065] Table 1

[0066] Location Fe Co Ni Al O N H superior 21.51 22.75 45.30 10.43 0.0005 0.0001 ＜0.0001 middle 21.54 22.73 45.28 10.44 0.0008 0.0002 0.0001 Down 21.51 22.72 45.31 10.45 0.0006 0.0002 0.0001

[0067] Example 2:

[0068] The manufacturing process of a high-entropy alloy directional solidification cylindrical component with a nominal composition of Fe3Co3Ni3AlVTi, and the dimensions of the cylindrical component are as follows. This can be achieved through the following steps:

[0069] 1. Raw materials: Pure Fe powder, pure Co powder, pure Ni powder, pure Al powder, NiTi alloy powder (Ni to Ti mass ratio of 1:1), and AlV55 alloy powder (Al to V mass ratio of 45:55) are used as raw materials. The powder particle size is 30-53μm, the purity of pure element powder is ≥99.5%, and the impurity content of NiTi alloy powder and AlV55 alloy powder is ≤0.5%. The melting point of the selected powders is lower than the highest temperature that can be achieved by directional furnace heating.

[0070] 2. The manufacturing process of high-entropy alloy directional solidification components includes the following 5 steps:

[0071] (1) Batching calculation: The batching calculation was performed based on the composition of the Fe3Co3Ni3AlVTi high-entropy alloy according to the atomic ratios of Fe 25%, Co 25%, Ni 25%, Al 8.3%, V 8.3%, and Ti 8.3%. Among them, the formula contents of non-burn-out elements Fe, Co, Ni, V, and Ti were directly obtained based on their weight percentages. However, Al, a high vapor pressure volatilization burn-out element, required a certain amount of compensation during the batching calculation. Based on the total weight of the batching and the weight percentage of Al, combined with sample tests, the final Al content was determined to be increased by 10% on the basis of the calculation.

[0072] (2) Weighing: Based on the calculation results of the ingredients, weigh the Fe powder, Co powder, Ni powder, Al powder, NiTi alloy powder and AlV55 alloy powder to be 259g, 273g, 183g, 12g, 165g and 112g respectively, and then dry them after preliminary mixing.

[0073] (3) Ball milling: The prepared powder is placed in a ball mill jar in an argon-protected glove box. The grinding balls are made of agate and the grinding jar is made of stainless steel. The ball-to-powder ratio is 10:1. The grinding jar is also protected by argon. A planetary ball mill is used with a rotation speed of 900 rad / min and a grinding time of 2 hours to make the powder mix evenly and grind each other.

[0074] (4) Powder loading: After wax molding, coating, dewaxing, and firing, a ceramic mold for directional solidification is obtained, and then the ball-milled powder is loaded into the mold. During the powder loading process, powder loading and powder compaction are carried out simultaneously. The mold is always placed on a vibrating platform to achieve the purpose of compacting the powder. The vibration frequency of the vibrating platform is 30Hz, and the vibration time is 40min. In addition, an inverted frustum-shaped feeding port is set at the top of the mold. After the powder melts, it forms a molten metal. The presence of the feeding port provides pressure for the molten metal to fill the mold and also compensates for the volume shrinkage during the solid-liquid transition of the molten metal. The completion of powder loading is marked by the filling port being filled with powder after compaction. The size of the feeding port is designed based on the mold volume and the compacted powder density, and a certain compensation amount is set. The specific calculation formula is: V r =k·V m (ρ HEA / ρ-1), where V r V represents the volume of the feed inlet. m Let ρ be the volume of the component. HEA ρ is the theoretical density of the high-entropy alloy, ρ is the powder tap density, and k is the compensation coefficient. Initial values ​​are set based on experience, and the final values ​​are determined experimentally. In this embodiment, V... m The value is 7.85cm 3 , ρ HEA The value is 7.51 g / cm³ 3 The ρ value is 4.5 g / cm³. 3 The value of k is 1.1, and the calculated volume of the feed inlet V is... r It should be 5.78cm. 3 .

[0075] (5) Directional solidification: Place the mold on the Bridgeman directional furnace base and turn on the vacuum pump to make the vacuum level inside the equipment ≤10. -1Pa, maintain vacuum, hold at 1600-1650℃ until the powder filling the mold is completely melted, then hold for another 30 minutes. At a moving speed of 0.06 mm / s, activate the pulling device and start directional stretching, so that the base moves vertically from top to bottom. The bottom of the mold comes into contact with the liquid gallium indium tin alloy coolant. Directional stretching causes the mold to gradually enter the liquid gallium indium tin alloy coolant for solidification (the working temperature of the coolant is room temperature), thereby obtaining a high-entropy alloy directional solidified cylindrical component with directional solidification structure of Fe3Co3Ni3AlVTi.

[0076] Example 3:

[0077] The nominal composition is AlCoCrFeNi 2.1 The manufacturing process of a high-entropy alloy directionally solidified cylindrical component, the cylindrical component having dimensions of... This can be achieved through the following steps:

[0078] 1. Raw materials: Pure Al powder, pure Co powder, pure Fe powder, pure Ni powder, and NiCr50 alloy powder (Ni to Cr mass ratio of 1:1) are used as raw materials. The powder particle size is 30-53μm, the purity of pure element powder is ≥99.5%, and the impurity content of NiCr50 alloy powder is ≤0.5%. The melting point of the selected powders is lower than the highest temperature that can be achieved by directional furnace heating.

[0079] 2. The manufacturing process of high-entropy alloy directional solidification components includes the following 5 steps:

[0080] (1) Ingredient calculation, based on AlCoCrFeNi 2.1 The high-entropy alloy composition was calculated based on the atomic ratios of Al 16.4%, Co 16.4%, Cr 16.4%, Fe 16.4%, and Ni 34.4%. The content of non-burning elements Co, Cr, Fe, and Ni was directly obtained based on their weight percentages. However, Al, a high vapor pressure volatilization and burn-off element, required a certain compensation amount during the composition calculation. Based on the total weight of the ingredients, the weight percentage of Al, and sample testing, the final Al content was determined to be 8% higher than the calculated amount.

[0081] (2) Weighing: Based on the ingredient calculation results, weigh Al powder, Co powder, Fe powder, Ni powder, and NiCr50 alloy powder to 92g, 186g, 176g, 204g, and 349g respectively, and then dry them after preliminary mixing.

[0082] (3) Ball milling: The prepared powder is placed in a ball mill jar in an argon-protected glove box. The grinding balls are made of corundum and the grinding jar is made of stainless steel. The ball-to-powder ratio is 8:1. Argon gas is also used to protect the grinding jar. A planetary ball mill is used with a rotation speed of 600 rad / min and a ball milling time of 1.5 h to make the powder mix evenly and grind each other.

[0083] (4) Powder loading: After wax molding, coating, dewaxing, and firing, a ceramic mold for directional solidification is obtained, and then the ball-milled powder is loaded into the mold. During the powder loading process, powder loading and powder compaction are carried out simultaneously. The mold is always placed on a vibrating platform to achieve the purpose of compacting the powder. The vibration frequency of the vibrating platform is 35Hz, and the vibration time is 30min. In addition, an inverted frustum-shaped feeding port is set at the top of the mold. After the powder melts, it forms a molten metal. The presence of the feeding port provides pressure for the molten metal to fill the mold and also compensates for the volume shrinkage during the solid-liquid transition of the molten metal. The completion of powder loading is marked by the filling port being filled with powder after compaction. The size of the feeding port is designed based on the volume of the component mold and the compaction density of the powder, and a certain compensation amount is set. The specific calculation formula is: V r =k·V m (ρ HEA / ρ-1), where V r V represents the volume of the feed inlet. m Let ρ be the volume of the component. HEA ρ is the theoretical density of the high-entropy alloy, ρ is the powder tap density, and k is the compensation coefficient. Initial values ​​are set based on experience, and the final values ​​are determined experimentally. In this embodiment, V... m The value is 7.85cm 3 , ρ HEA The value is 7.45 g / cm³ 3 The ρ value is 4.4 g / cm³. 3 The value of k is 1.2, and the calculated volume of the feed inlet V is... r It should be 6.53cm 3 .

[0084] (5) Directional solidification: Place the mold on the Bridgeman directional furnace base and turn on the vacuum pump to make the vacuum level inside the equipment ≤10. -1 Under vacuum, the temperature is maintained at 1600–1650℃ until the powder filling the mold is completely melted, then held for another 30 minutes. The pulling device is activated at a moving speed of 0.05 mm / s to initiate directional stretching, causing the base to move vertically from top to bottom. The bottom of the mold comes into contact with the liquid gallium indium tin alloy coolant. Directional stretching causes the mold to gradually enter the liquid gallium indium tin alloy coolant for solidification (the coolant's operating temperature is room temperature), thus obtaining an AlCoCrFeNi alloy with a directional solidification structure. 2.1 High-entropy alloy directional solidification cylindrical components.

[0085] Example 4:

[0086] The manufacturing process of a high-entropy alloy directional solidification cylindrical component with a nominal composition of AlCrFeNi2Ti, the cylindrical component having dimensions of... This can be achieved through the following steps:

[0087] 1. Raw materials: Pure Al powder, pure Fe powder, NiTi alloy powder, and NiCr50 alloy powder (Ni to Cr mass ratio of 1:1) are used as raw materials. The powder particle size is 30-53μm, the purity of pure element powder is ≥99.5%, and the impurity content of NiTi alloy powder and NiCr50 alloy powder is ≤0.5%. The melting point of the selected powders is lower than the highest temperature that can be achieved by directional furnace heating.

[0088] 2. The manufacturing process of high-entropy alloy directional solidification components includes the following 5 steps:

[0089] (1) Batching calculation: The batching calculation was performed based on the AlCrFeNi2Ti high-entropy alloy composition according to the atomic ratio of Al 20%, Cr 20%, Fe 20%, Ni 20%, and Ti 20%. Among them, the formula contents of non-burn-out elements Cr, Fe, Ni, and Ti were directly obtained based on their weight percentages. However, Al, a high vapor pressure volatilization burn-out element, required a certain compensation amount during the batching calculation. Based on the total weight of the batching and the weight percentage of Al element, combined with sample tests, the final Al content was determined and increased by 5% on the basis of the calculation.

[0090] (2) Weighing: Based on the ingredient calculation results, weigh Al powder, Fe powder, NiTi alloy powder and NiCr50 alloy powder to 90g, 186g, 356g and 370g respectively, and then dry them after preliminary mixing.

[0091] (3) Ball milling: The prepared powder is placed in a ball mill jar in an argon-protected glove box. The grinding balls are made of corundum and the grinding jar is made of stainless steel. The ball-to-powder ratio is 5:1. Argon gas is also used to protect the grinding jar. A planetary ball mill is used with a rotation speed of 400 rad / min and a ball milling time of 3 hours to make the powder mix evenly and grind each other.

[0092] (4) Powder loading: After wax molding, coating, dewaxing, and firing, a ceramic mold for directional solidification is obtained, and then the ball-milled powder is loaded into the mold. During the powder loading process, powder loading and powder compaction are carried out simultaneously. The mold is always placed on a vibrating platform to achieve the purpose of compacting the powder. The vibration frequency of the vibrating platform is 25Hz, and the vibration time is 25min. In addition, an inverted frustum-shaped feeding port is set at the top of the mold. After the powder melts, it forms a molten metal. The presence of the feeding port provides pressure for the molten metal to fill the mold and also compensates for the volume shrinkage during the solid-liquid transition of the molten metal. The completion of powder loading is marked by the filling port being filled with powder after compaction. The design of the feeding port size is calculated based on the component mold volume and the compacted powder density, and a certain compensation amount is set. The specific calculation formula is: V r =k·V m (ρ HEA / ρ-1), where V r V represents the volume of the feed inlet. m Let ρ be the volume of the component. HEA ρ is the theoretical density of the high-entropy alloy, ρ is the powder tap density, and k is the compensation coefficient. Initial values ​​are set based on experience, and the final values ​​are determined experimentally. In this embodiment, V... m The value is 7.85cm 3 , ρ HEA The value is 6.68 g / cm³ 3 The ρ value is 4.0 g / cm³. 3 The value of k is 1.1, and the calculated volume of the feed inlet V is... r It should be 5.79cm 3 .

[0093] (5) Directional solidification: Place the mold on the Bridgeman directional furnace base and turn on the vacuum pump to make the vacuum level inside the equipment ≤10. -1 Pa, maintain vacuum, hold at 1570-1600℃ until the powder filling the mold is completely melted, then hold for another 20 minutes. At a moving speed of 0.08 mm / s, activate the pulling device and start directional stretching, so that the base moves vertically from top to bottom. The bottom of the mold comes into contact with the liquid gallium indium tin alloy coolant. Directional stretching causes the mold to gradually enter the liquid gallium indium tin alloy coolant for solidification (the working temperature of the coolant is room temperature), thereby obtaining a high-entropy alloy directional solidified cylindrical component of AlCrFeNi2Ti with directional solidification structure.

[0094] Example 5:

[0095] The nominal composition is AlCoCrFeNi 2.1The manufacturing process of high-entropy alloy directional solidification blade components, the blade component length is 90mm. When the component shape is a blade, the vibration frequency of the vibration platform in embodiment (4) is 30Hz, and the vibration time is 35min. Except for the specific embodiment, it is the same as that in embodiment 3, and the resulting product structure is as follows. Figure 5 As shown, 1 is the feed inlet, 2 is the tenon, 3 is the blade body, and 4 is the blade crown. Removing the feed inlet yields AlCoCrFeNi. 2.1 High-entropy alloy directional solidification blade components.

[0096] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a high-entropy alloy directional solidification component, characterized in that, include: (1) The raw material powder for preparing high-entropy alloy directional solidification components is ball-milled and mixed evenly to obtain a mixture. The mixture is then placed in a mold with a feeding port, and the mixture is densified at the same time. (2) Heat the raw material powder until it melts, keep it warm, and then make the mold move in a directional manner. Cool it while it moves in a directional manner, remove the mold, and obtain a high-entropy alloy directional solidification component. The speed of the directional movement is 0.06~0.2 mm / s; After the mixture is placed into the mold, before the directional solidification is carried out, a compensation amount of raw material powder is added; The compensation amount of the raw material powder is calculated according to Formula 1; V r =k·V m (ρ HEA Formula 1 ( / ρ-1); Among them, V r For compensation amount, V m Let ρ be the volume of the component. HEA ρ is the theoretical density of the high-entropy alloy, ρ is the tap density of the powder, and k is the compensation coefficient, 1.0≤k≤1.

5.

2. The method for preparing a high-entropy alloy directional solidification component according to claim 1, characterized in that, The directional solidification is carried out under vacuum or inert gas conditions.

3. The method for preparing a high-entropy alloy directional solidification component according to claim 2, characterized in that, The vacuum degree of the directional solidification is ≤10. -1 Pa.

4. The method for preparing a high-entropy alloy directional solidification component according to claim 1, characterized in that, The cooling is performed using liquid metal.

5. The method for preparing a high-entropy alloy directional solidification component according to claim 1, characterized in that, The heat preservation time is 10~30 minutes.

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