High-Re-content nickel-based high-temperature alloy and preparation method thereof

Abstract

The invention relates to a high-Re-content nickel-based high-temperature alloy and a preparation method thereof, and the preparation method comprises the following steps: preparing a first raw material and a second raw material; the elements provided by the first raw material comprise C, Cr, Ni, W, Co, Mo, Nb and Ta; the second raw material comprises rhenium-aluminum-cobalt intermediate alloy and elementary substance Al; the first raw material is subjected to melting and alloying refining treatment; then the temperature of the melt is reduced to the temperature for homogenization treatment, after rhenium-aluminum-cobalt intermediate alloy is added into the melt for homogenization treatment, Al is added for homogenization treatment, and alloy liquid obtained after homogenization treatment is obtained; and the alloy liquid is subjected to pouring treatment, and the high-Re-content nickel-based high-temperature alloy is obtained. The method is used for improving the component uniformity of the rhenium-containing nickel-based high-temperature alloy and reducing the generation of a TCP phase, so that the nickel-based single-crystal high-temperature alloy has good durability, tensile property and structure stability, and is suitable for high-temperature parts of aviation and airspace engines and high-temperature parts of gas turbines.

Description

Technical Field

[0001] The invention relates to the technical field of high-temperature alloys, and in particular to a nickel-based high-temperature alloy with a high Re content and a preparation method thereof. Background Art

[0002] High-temperature alloy is an alloy that can work above 600℃ and can withstand certain stress. It plays an important role in hot end components such as aircraft engines, rocket engines and gas turbines. Therefore, it needs to have good organizational stability and excellent high-temperature performance. Nickel-based high-temperature alloy is one of the high-temperature alloys with the best comprehensive performance. It accounts for about 40% of the field of high-temperature alloys and is widely used in the aviation and aerospace industries. Nickel-based alloys can accommodate more alloying elements in the solid solution state, and more than 10 alloying elements are often added. Among them, the main elements Ni, Cr, Al, etc. can be used to improve the oxidation resistance, corrosion resistance and metallurgical stability of the alloy. Studies have shown that adding refractory elements to the alloy can significantly improve the temperature bearing capacity of the alloy, such as Re, W, Mo, Nb, Ta, etc.

[0003] Among them, high Re content nickel-based superalloys are important component characteristics of high-generation single crystal alloys. Re elements can improve alloy strength, inhibit the growth of γ' strengthening phase and increase γ / γ' mismatch, reduce grain defects and surface recrystallization of single crystal castings, but too many refractory alloying elements are easy to precipitate in the γ matrix and form TCP phase. The formation of TCP phase will accelerate the generation and expansion of cracks, reduce the durability of the alloy, and shorten the creep rupture life of the alloy. In addition, in nickel-based superalloys with high Re content, the melting points of various alloying elements are quite different. When the solidification rate of the alloy is inconsistent, Re elements are easy to precipitate in the dendrite stem, and Al, Ta, Ru, and Co are easy to precipitate between dendrites, resulting in uneven distribution of components in the target alloy. In addition, the refractory element Re will promote the precipitation of TCP phase, which has a great impact on the performance of the alloy.

[0004] In summary, for nickel-based high-temperature alloys with high Re content, it is urgent to provide a preparation method to reduce the precipitation of TCP phase and improve the uniformity of alloy element distribution, thereby improving the performance of the alloy. Summary of the invention

[0005] In view of this, the present invention provides a nickel-based high-temperature alloy with a high Re content and a preparation method thereof, the main purpose of which is to reduce the precipitation of TCP phase and improve the uniformity of alloy element distribution.

[0006] In order to achieve the above object, the present invention mainly provides the following technical solutions:

[0007] On the one hand, an embodiment of the present invention provides a method for preparing a nickel-based high-temperature alloy with a high Re content, wherein the Re content in the nickel-based high-temperature alloy with a high Re content is 3.3-4.5 wt %; wherein the preparation method comprises the following steps:

[0008] Raw material preparation step: preparing a first raw material and a second raw material; wherein the elements provided by the first raw material include C, Cr, Ni, W, Co, Mo, Nb, and Ta; and the second raw material includes: a rhenium-aluminum-cobalt master alloy and a single substance Al for providing Re, Al, and Co elements;

[0009] Vacuum melting step: firstly, melting and alloying and refining the first raw material; then, lowering the temperature of the melt to a homogenization temperature, adding the rhenium-aluminum-cobalt master alloy to the melt for homogenization, and then adding single Al to the melt for homogenization to obtain a homogenized alloy liquid;

[0010] Pouring step: pouring the alloy liquid after the homogenization treatment to obtain a nickel-based high-temperature alloy with a high Re content.

[0011] Preferably, in the rhenium-aluminum-cobalt master alloy: the mass fraction of Re is 15-40wt%, the mass fraction of Al is 10-35wt%, and Co is the balance.

[0012] Preferably, the steps of preparing the rhenium-aluminum-cobalt master alloy include:

[0013] The method comprises the following steps: smelting and purifying single substance cobalt to obtain a cobalt melt; adding single substance rhenium to the cobalt melt to perform a first alloying treatment; when the melt after the first alloying treatment is cooled to a temperature 30 to 50° C. higher than the liquidus line of the melt, adding single substance aluminum to the melt to perform a second alloying treatment; homogenizing the melt after the second alloying treatment; and pouring the homogenized melt to obtain a rhenium-aluminum-cobalt master alloy;

[0014] Preferably, the temperature of the first alloying treatment is 1550-1600°C, and the time of the first alloying treatment is 10-30 minutes;

[0015] Preferably, the temperature of the second alloying treatment is 1500-1550°C, and the time of the second alloying treatment is 10-30 minutes;

[0016] Preferably, the temperature of the homogenization treatment is 50-60° C. higher than the liquidus temperature of the desired rhenium-aluminum-cobalt master alloy;

[0017] Preferably, the homogenization treatment time is 10 to 15 minutes;

[0018] Preferably, the pouring temperature is 10-20°C higher than the homogenization temperature;

[0019] Preferably, the content ratio of each element in the rhenium-aluminum-cobalt master alloy is determined according to the mass fraction of rhenium, aluminum and cobalt in the high Re content nickel-based high-temperature alloy; according to the content ratio of each element in the rhenium-aluminum-cobalt master alloy, elemental rhenium, elemental aluminum and elemental cobalt are weighed; further preferably, the weighed elemental rhenium and elemental aluminum are respectively wrapped with aluminum foil.

[0020] Preferably, the high Re content nickel-based high temperature alloy comprises the following chemical components in terms of weight percentage:

[0021] Cr 4.0~6.0wt%, Al 5.5~6.5wt%, Co 8~10wt%, Mo 0.5~1.5wt%, Nb1.5~1.8wt%, W 8.0~9.5wt%, Ta 3.5~4.5wt%, Re 3.3~4.5wt%, C 0.10~0.20wt%, and the rest is Ni;

[0022] Preferably, in the nickel-based high-temperature alloy with high Re content, the weight percentage of impurities meets the following requirements: O≤5ppm, N≤5ppm, S≤5ppm.

[0023] Preferably, in the high Re content nickel-based high temperature alloy:

[0024] The ratio of the weight percentage of the Re element to the weight percentage of the Al element is set to 1.0-3.0; the sum of the weight percentage of the Re element and the weight percentage of the Al element is 35-70wt%.

[0025] Preferably, in the vacuum melting step:

[0026] First, the first raw material is loaded into a melting crucible in the order of C, Cr, Ni, W, Co, Mo, Nb, and Ta, and is melted, alloyed, and refined. After the raw material is completely refined, the rhenium-aluminum-cobalt master alloy is added thereto for homogenization. Then, single Al is added to the melt for homogenization to obtain a homogenized alloy liquid.

[0027] Preferably, in the vacuum melting step:

[0028] The first raw material is placed in a crucible for vacuum melting. When the vacuum degree is less than 5 Pa, electric melting is started. At 1550-1600° C., alloying refining is performed. Then, the temperature of the melt is lowered to 1400-1450° C., and the rhenium-aluminum-cobalt master alloy is added thereto for homogenization treatment. Then, single Al is added to the melt for homogenization treatment to obtain a homogenized alloy liquid.

[0029] Preferably, the alloying refining treatment time is 20-30 minutes;

[0030] Preferably, the time for adding the rhenium-aluminum-cobalt master alloy and performing homogenization treatment is 30-40 minutes;

[0031] Preferably, when the homogenization treatment is performed, electromagnetic stirring treatment is required; further preferably, the time of the electromagnetic stirring treatment is 10-15 minutes.

[0032] Preferably, the homogenization treatment is performed for 10-15 minutes after adding the elemental Al.

[0033] Preferably, in the pouring step: the alloy liquid after the homogenization treatment is heated to a temperature 70-100° C. higher than the liquidus line of the alloy liquid after the homogenization treatment, and then the pouring treatment is performed to obtain a nickel-based high-temperature alloy with a high Re content.

[0034] On the other hand, an embodiment of the present invention provides a high Re content nickel-based high temperature alloy, characterized in that the high Re content nickel-based high temperature alloy is prepared by the preparation method of the high Re content nickel-based high temperature alloy preparation method described in any one of the above. Preferably, in the cast structure of the high Re content nickel-based high temperature alloy, the primary dendrite spacing is 0.3 to 0.4 mm. In addition, the primary dendrites are evenly distributed, the secondary dendrite morphology is relatively regular, and the eutectic distribution is relatively uniform, and no obvious TCP phase appears.

[0035] In another aspect, an embodiment of the present invention provides a nickel-based single crystal high-temperature alloy with a high Re content, wherein the steps of preparing the nickel-based single crystal high-temperature alloy with a high Re content include:

[0036] 1) Using any one of the above methods for preparing a nickel-based high-temperature alloy with a high Re content, a nickel-based high-temperature alloy with a high Re content is prepared;

[0037] 2) The high Re content nickel-based high temperature alloy is prepared into a high Re content nickel-based single crystal high temperature alloy.

[0038] Compared with the prior art, the high Re content nickel-based single crystal high temperature alloy and the preparation method thereof of the present invention have at least the following beneficial effects:

[0039] The embodiment of the present invention provides a high Re content nickel-based high temperature alloy and a preparation method thereof. Because the Co element can be well dissolved in Ni, the refractory element Re is combined with Al and Co elements, and smelted into an intermediate alloy as a raw material for preparing a target alloy, and then combined with a first raw material (the elements provided by the first raw material include C, Cr, Ni, W, Co, Mo, Nb, Ta) and single Al to prepare the target alloy, thereby reducing the precipitation of TCP phase and improving the uniformity of element distribution in the alloy, thereby improving the purity and organizational stability of the alloy. In addition, the refractory element Re improves the solubility of Re in the Ni-based alloy through the preparation of the intermediate alloy, effectively preventing the precipitation of the refractory element, further developing the application potential of the high Re content nickel-based high temperature alloy, and improving the performance of the nickel-based single crystal high temperature alloy after preparing it into a nickel-based single crystal high temperature alloy.

[0040] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a microstructure diagram of a nickel-based single crystal high-temperature alloy with a high Re content prepared in Example 1 of the present invention;

[0042] Figure 2 is a microstructure diagram of a nickel-based single crystal high-temperature alloy with a high Re content prepared in Example 2 of the present invention;

[0043] Figure 3 This is a microstructure diagram of a nickel-based single crystal high-temperature alloy with a high Re content prepared in Comparative Example 1 of the present invention.

[0044] Figure 4 3 is a microstructure diagram of the Re-Al-Co master alloy prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0045] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention application are described in detail below in conjunction with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures, or characteristics in one or more embodiments may be combined in any suitable form.

[0046] On the one hand, an embodiment of the present invention provides a method for preparing a nickel-based high-temperature alloy with a high Re content, comprising the following steps:

[0047] Raw material preparation step: prepare a first raw material and a second raw material; wherein the elements provided by the first raw material include C, Cr, Ni, W, Co, Mo, Nb, and Ta; the second raw material includes: a rhenium-aluminum-cobalt intermediate alloy and a single substance Al for providing Re, Al, and Co elements.

[0048] It should be noted here that: Regarding the rhenium-aluminum-cobalt master alloy, Co element is selected as the matrix because the master alloy prepared with cobalt element as the matrix can be infinitely dissolved in the Ni-based high-temperature alloy, which can effectively reduce the alloy segregation and the formation of impurities, improve the grain boundary strengthening effect of the alloy, and improve the high-temperature durability of the alloy, as well as enhance the high-temperature strength and corrosion resistance of the alloy.

[0049] According to the Co-Re binary phase diagram, Al-Co binary phase diagram, and Al-Re binary phase diagram, it can be seen that: since Al-Re elements can exist in the form of solid solution, when the ratio of the three alloy elements reaches a certain range, it can ensure that Re exists in the form of complete solid solution in this ternary alloy Al-Co-Re, and achieve uniform distribution of Al, Co, and Re elements. In addition, the phase transition point of Co-Al intermetallic compounds is low, and intermetallic compounds will not be formed after rapid cooling. Therefore, Al-Co-Re master alloys are selected to exist in the form of pure solid solution and are used for the preparation of high-Re content nickel-based high-temperature alloys.

[0050] Among them, in the rhenium-aluminum-cobalt master alloy: the mass fraction of Re is 15-40wt%, the mass fraction of Al is 10-35wt%, and Co is the balance. Here, as a refractory element, Re has a low solubility in the alloy. Excessive addition of Re will lead to element segregation or metal inclusions in the master alloy. The control of the mass fraction of each element in the above master alloy is to ensure that the Re and Al elements in the intermediate gold have a good uniform distribution of composition in the Co matrix.

[0051] Wherein, in this step: the preparation steps for the rhenium-aluminum-cobalt master alloy are as follows:

[0052] The chemical composition of the rhenium-aluminum-cobalt master alloy is determined according to the weight percentage of rhenium, aluminum and cobalt in the high-Re content nickel-based high-temperature alloy. According to the chemical composition of the rhenium-aluminum-cobalt master alloy, the raw materials of rhenium, aluminum and cobalt are weighed; the weighed rhenium and aluminum are wrapped with aluminum foil respectively. First, the cobalt is smelted and purified, and then rhenium is added to the melt, and the alloying treatment is carried out at 1550-1600°C for 10-30 minutes to ensure that there are no large number of Re atomic clusters in the alloy melt; when the power is turned off and the temperature is cooled to 30-50°C above the liquidus, aluminum is added for the second alloying treatment, and the refining temperature is kept within 50-60°C above the target master alloy liquidus temperature for 20-40 minutes for homogenization treatment; after the homogenization treatment, the melt temperature is increased by 10-20°C for casting to obtain the rhenium-aluminum-cobalt master alloy.

[0053] Preferably, the first raw material includes single substance Co, single substance C, single substance Cr, single substance W, single substance Ni, single substance Mo, single substance Nb, single substance Ta and single substance Al; the second raw material includes Re-Al-Co master alloy and single substance Al, and the principle of use is that Re single substance does not need to be added in the process of preparing the target high temperature alloy using the first and second raw materials. Among them, the first raw material is first loaded into the crucible in the order of C, Cr, Ni, W, Co, Mo, Nb, and Ta, and then melted and alloyed and refined; after complete purification, Re-Al-Co master alloy is added according to actual control needs for homogenization treatment, and finally single substance Al is added for homogenization treatment. Preferably, the time for homogenization treatment after adding single substance Al is 10-15min.

[0054] Vacuum melting step: firstly melt the first raw material, perform alloying and refining treatment; then, lower the temperature of the melt to a homogenization treatment temperature, add Re-Al-Co master alloy to the melt for homogenization treatment, and then, add Al to the melt for homogenization treatment to obtain a homogenized alloy liquid.

[0055] Among them, in this step: the first raw material is loaded into a crucible and vacuum smelted. When the vacuum degree is less than 5Pa, electric melting is started; at 1550-1600°C, alloying and refining are performed; then, the temperature of the melt is reduced to 1400-1450°C, and Re-Al-Co master alloy is added thereto for homogenization treatment; then, Al is added to the melt for homogenization treatment to obtain a homogenized alloy liquid. Preferably, the alloying and refining treatment time is 20-30min; preferably, after adding the Re-Al-Co master alloy, the homogenization treatment time is 30-40min; preferably, when the homogenization treatment is performed, electromagnetic stirring treatment is required; further preferably, the electromagnetic stirring treatment time is 10-15min.

[0056] Pouring step: pouring the alloy liquid after the homogenization treatment to obtain a nickel-based high-temperature alloy with a high Re content.

[0057] Wherein, in this step: the alloy liquid after the homogenization treatment is heated to 70-100° C. higher than the liquidus line (liquidus line of the alloy liquid after the homogenization treatment), and then the casting treatment is performed.

[0058] Preferably, the high Re content nickel-based high-temperature alloy includes the following chemical components, in terms of weight percentage: Cr 4.0-6.0wt%, Al 5.5-6.5wt%, Co 8-10wt%, Mo 0.5-1.5wt%, Nb 1.5-1.8wt%, W 8.0-9.5wt%, Ta 3.5-4.5wt%, Re 3.3-4.5wt%, C 0.10-0.20wt%, and the rest is Ni.

[0059] Preferably, the ratio of the weight percentage of the Re element to the weight percentage of the Al element is 1.0 to 3.0; and the sum of the weight percentage of the Re element and the weight percentage of the Al element is 35 to 70 wt %.

[0060] The present invention is further described below by preferred embodiments:

[0061] Example 1

[0062] Example 1 Preparation of a high Re content nickel-based high temperature alloy, wherein the smelting mass is 50 kg. According to the chemical composition of the target alloy, a Re-Al-Co master alloy is first prepared; here, according to the chemical composition requirements of the prepared high Re content nickel-based high temperature alloy, the chemical composition of the Re-Al-Co master alloy is designed, and then the target alloy is prepared. The calculated batching points are shown in Table 1.

[0063] Table 1 is the ingredient list of nickel-based single crystal high-temperature alloy

[0064]

[0065] Regarding Co in Table 1, it refers to the mass fraction of the added Co element. The Re-Al-Co master alloy also contains a portion of Co, and the sum of the two falls within the range selected for the nickel-based high-temperature alloy.

[0066] The preparation method of the high Re content nickel-based high temperature alloy of this embodiment mainly comprises the following steps:

[0067] 1) First, prepare a Re-Al-Co master alloy. Considering the burning of raw materials, the raw materials of the master alloy can be proportioned according to 30% aluminum, 40% rhenium, and the balance is cobalt. The required preparation weight is weighed, and the rhenium and aluminum are wrapped in aluminum foil respectively for later use.

[0068] Aluminum-based crucibles are used for Re-Al-Co master alloy smelting. Co is placed in the crucible for smelting. Re is added after purifying, and the first alloying treatment is carried out at a temperature of 1550°C for 30 minutes. Power is turned off and the temperature is cooled. When solidification is observed at the edge of the melt, high-purity Ar gas is filled until the vacuum meter shows 0.06KPa. At this time, the minimum heating power (1 / 4-1 / 2 of the homogenization power) is input. At this time, the temperature is reduced to 30-50°C higher than the liquidus of the melt. Al is added to the melt, and the second alloying treatment is carried out at 1500°C for 30 minutes, and then a homogenization treatment is carried out (the temperature of the homogenization treatment is 50-60°C higher than the liquidus temperature of the required rhenium-aluminum-cobalt master alloy, and the homogenization treatment time is 10 minutes). After the end, the temperature is raised to 70°C of the liquidus for casting to obtain a master alloy ingot.

[0069] The raw materials are weighed according to the target alloy composition, and the corresponding weight of the intermediate alloy ingot is cut. The principle of using the intermediate alloy is that the calculated Co, Re and Al contents do not exceed the upper limit of the target alloy.

[0070] Figure 4 : is a microstructure diagram of the Re-Al-Co master alloy prepared in Example 1 of the present invention. Figure 4 It can be seen that there are no obvious defects and component segregation problems in the alloy, indicating that the components in the ternary alloy are evenly distributed.

[0071] 2) The first raw material is loaded into the crucible in the order of C, Cr, Ni, W, Co, Mo, Nb, and Ta, and vacuum smelting is performed. When the vacuum degree is <5Pa, power melting is started (power melting is to supply power to the vacuum induction furnace to melt the raw materials in the crucible). At a temperature of 1550°C, alloying and refining treatment is performed for 20 minutes, and then the temperature is lowered to 1400°C, and the prepared Re-Al-Co master alloy is added to the melt for homogenization treatment (i.e., secondary alloying), and the temperature is kept for 30 minutes (i.e., homogenization treatment for 30 minutes), and then single Al is added for homogenization treatment for 10 minutes to obtain a homogenized alloy liquid.

[0072] 3) The alloy liquid after homogenization treatment is heated to 1460° C. and poured to obtain a nickel-based high-temperature alloy with a high Re content.

[0073] The chemical composition of the upper and lower parts of the high Re content nickel-based high temperature alloy prepared in this embodiment was tested and analyzed (i.e., samples were taken near the head and tail ends of the rod-shaped alloy ingot in this embodiment) to examine the uniformity of the alloy composition. The test results are shown in Table 2. It can be seen from Table 2 that the chemical composition control accuracy is ±0.05%, the uniformity and purity of the master alloy composition are good, and the primary dendrite spacing in the alloy prepared in this embodiment is small, such as Figure 1 As shown, the primary dendrite spacing is about 0.393 mm, the primary dendrites are evenly distributed, the secondary dendrite morphology is relatively regular, and the eutectic distribution is relatively uniform, and no obvious TCP phase appears.

[0074] Table 2 Chemical composition of the upper and lower parts of the high Re content nickel-based high-temperature alloy prepared in this embodiment (mass fraction, wt%)

[0075]

[0076] Example 2

[0077] Example 2 A high-Re content nickel-based high-temperature alloy is prepared, wherein the smelting mass is 50 kg. According to the chemical composition of the target alloy, a Re-Al-Co master alloy is first prepared; here, according to the chemical composition requirements of the prepared high-Re content nickel-based high-temperature alloy, the chemical composition of the Re-Al-Co master alloy is designed, and then the target alloy is prepared. The calculated batching points are shown in Table 3.

[0078] Table 3 Nickel-based single crystal high temperature alloy ingredients

[0079]

[0080] Regarding Co in Table 3, it refers to the mass fraction of added Co element. The Re-Al-Co master alloy also contains a portion of Co. The sum of the two falls within the range selected for the nickel-based high-temperature alloy.

[0081] The preparation method of the high Re content nickel-based high temperature alloy of this embodiment mainly comprises the following steps:

[0082] 1) First, prepare a Re-Al-Co master alloy. Considering the burning of raw materials, the raw materials of the master alloy can be proportioned according to 30% aluminum, 35% rhenium, and the balance Co. The required material mass is weighed, and the rhenium and aluminum are wrapped in aluminum foil respectively for later use.

[0083] Aluminum-based crucibles are used for Re-Al-Co master alloy smelting. Co is placed in the crucible for smelting. Re is added after purifying, and the first alloying treatment is performed at a temperature of 1550°C for 10 minutes. Power is turned off to cool down. When solidification is observed at the edge of the melt, high-purity Ar gas is filled until the vacuum meter shows 0.06KPa. At this time, the minimum heating power (homogenizing power 1 / 4-1 / 2) is input. When the melt after the first alloying treatment is cooled to 30-50°C higher than the liquidus of the melt, Al is added to the melt, and the second alloying treatment is performed at 1500°C for 10 minutes. The melt after the second chemical treatment is homogenized (the homogenizing temperature is 50-60°C higher than the liquidus temperature of the required rhenium-aluminum-cobalt master alloy), and the temperature is raised to 70°C above the liquidus for casting to obtain a master alloy ingot.

[0084] The raw materials are weighed according to the target alloy composition, and the corresponding weight of the intermediate alloy ingot is cut. The principle of using the intermediate alloy is that the calculated Co, Re and Al contents do not exceed the upper limit of the target alloy.

[0085] 2) The first raw material is loaded into the crucible in the order of C, Cr, Ni, W, Co, Mo, Nb, and Ta, and vacuum smelting is performed. When the vacuum degree is <5Pa, power melting is started (power melting is to supply power to the vacuum induction furnace to melt the raw materials in the crucible). At a temperature of 1550°C, alloying and refining treatment is performed for 20 minutes, and then the temperature is lowered to 1400°C, and the prepared Re-Al-Co master alloy is added to the melt for homogenization treatment (i.e., secondary alloying), and the temperature is kept for 30 minutes (i.e., homogenization treatment for 30 minutes), and finally single Al is added for homogenization treatment to obtain a homogenized alloy liquid.

[0086] 3) The alloy liquid after homogenization treatment is heated to 1460° C. and poured to obtain a nickel-based high-temperature alloy ingot with a high Re content and low TCP phase precipitation.

[0087] The chemical composition of the upper and lower parts of the nickel-based high-temperature alloy ingot prepared in this embodiment was tested and analyzed (i.e., samples were taken near the head and tail ends of the rod-shaped alloy ingot in this embodiment) to examine the uniformity of the alloy composition. The test results are shown in Table 4. It can be seen from Table 4 that the chemical composition control accuracy is ±0.05%, the uniformity and purity of the master alloy composition are good, and the dendrite spacing is small. Figure 2 As shown in the figure, the primary dendrites are evenly distributed, the secondary dendrites are relatively regular in morphology, the primary dendrite spacing is about 0.365 mm, and the eutectic distribution is relatively uniform, without obvious TCP phase.

[0088] Table 4 Chemical composition of the upper and lower parts of the alloy ingot prepared by the present invention (mass fraction, wt%)

[0089]

[0090] Comparative Example 1

[0091] In comparative example 1, a nickel-based single crystal high-temperature alloy is prepared, the smelting mass is 50 kg, and the alloy ingot specification is φ85×1000 mm.

[0092] The specific steps are as follows:

[0093] 1) Set the batching point according to the chemical composition of the alloy: Cr4.0%~6.0%, Al5.5%~6.5%, Co8%~10%, Mo0.5%~1.5%, Nb1.5%~1.8%, W8.0%~9.5%, Ta3.5%~4.5%, Re3.3%~4.5%, C0.10%~0.20%, and the rest is Ni. The specific addition amount is shown in Table 5.

[0094] Table 5 Nickel-based single crystal high-temperature alloy batching points

[0095] raw materials Mass percentage, wt% Weigh the mass, kg C 0.15％ 0.075 Cr 4.5％ 2.25 Co 9％ 4.5 Mo 1.3％ 0.65 W 8.5％ 4.25 Al 5.85％ 2.925 Re 4.1％ 2.05 Nb 1.5％ 0.75 Ta 3.8％ 1.9 Ni margin 30.65

[0096] 2) Load the raw materials into the crucible in the order of C, Cr, Ni, W, Co, Mo, Nb, and Ta, and perform vacuum induction melting. Melt the raw materials in the crucible until they are clear, and then adjust the temperature to 1500℃ for high-temperature refining for 45min. After the first refining, turn off the power and cool down for at least 10min, then add Re and Al raw materials through side feeding, and continue stirring for at least 10min. After the power is turned off and the temperature is cooled, adjust the melt temperature to 1395℃ and perform low-temperature refining for 50min. During the melting process, the vacuum degree in the furnace is not higher than 40Pa. After adding the raw materials with lower melting points, increase the equipment power to 750-800kW, and increase the melting temperature until the raw materials are clear. Control the equipment power after clearing within the range of 250-300kW to ensure that the melt surface does not solidify during the feeding. After the feeding is completed, reduce the power to about 1 / 2 of the high-temperature refining power, and then stir for at least 10min.

[0097] 3) After low-temperature refining is completed, the temperature is raised to 1460°C and poured to obtain a uniform Re-containing nickel-based high-temperature alloy.

[0098] The alloy ingot of the nickel-based high-temperature alloy of this comparative example was sampled at the upper and lower ends. The chemical compositions of the upper and lower end structures of the alloy ingot of this embodiment are shown in Table 6.

[0099] Table 6 Chemical composition of the upper and lower parts of the alloy ingot prepared by the present invention (mass fraction, wt%)

[0100]

[0101] It can be seen from Table 6 that the chemical composition uniformity of the nickel-based single crystal high-temperature alloy prepared according to the comparative example 1 is poor, the main element deviation is high, the Al, Re, Ta and W elements in the upper and lower structures in the comparative example are relatively large, and the composition deviation of some elements at the upper and lower ends is relatively large, indicating that some elements are unevenly distributed. It is reasonable to guess that there is precipitation of TCP phase or some alloy elements inside. Figure 3 By comparison, it is found that the primary dendrite spacing of the nickel-based high-temperature alloy prepared by the method of Comparative Example 1 is larger. Therefore, this alloy smelting method is not suitable for the preparation of high-Re nickel-based alloys.

[0102] Comparative Example 2

[0103] Comparative Example 2: Preparation of a nickel-based high-temperature alloy with a high Re content, wherein the smelting mass is 50 kg. According to the chemical composition of the target alloy, a Re-Al-Co master alloy is first prepared; here, according to the chemical composition requirements of the prepared nickel-based high-temperature alloy with a high Re content, the chemical composition of the Re-Al-Co master alloy is designed, and then the target alloy is prepared. The batching points are calculated as shown in Table 7.

[0104] Table 7 is the ingredient list of nickel-based single crystal high-temperature alloy

[0105]

[0106] Regarding Co in Table 7, it refers to the mass fraction of the added Co element. The Re-Al-Co master alloy also contains a portion of Co, and the sum of the two falls within the range selected for the nickel-based high-temperature alloy.

[0107] The preparation method of the high Re content nickel-based high temperature alloy of this comparative example mainly comprises the following steps:

[0108] 1) First, prepare a Re-Al-Co master alloy. The master alloy raw materials can be mixed according to 20% aluminum, 50% rhenium, and the balance is cobalt. The required preparation weight is weighed, and the rhenium and aluminum are respectively wrapped with aluminum foil for later use.

[0109] Aluminum-based crucibles are used for Re-Al-Co master alloy smelting. Co is placed in the crucible for smelting. Re is added after purifying, and the first alloying treatment is performed at a temperature of 1550°C for 30 minutes. Power is turned off and the temperature is cooled. When solidification is observed at the edge of the melt, high-purity Ar gas is filled until the vacuum meter shows 0.06KPa. At this time, the minimum heating power (1 / 4-1 / 2 of the homogenization power) is input. When the melt is cooled to 30-50°C above the liquidus of the melt, Al is added to the melt, and the second alloying treatment is performed at 1500°C for 30 minutes. The melt after the second alloying treatment is homogenized (the homogenization temperature is 50-60°C higher than the liquidus temperature of the required rhenium-aluminum-cobalt master alloy), and the temperature is raised to 70°C of the liquidus for casting after the end to obtain a master alloy ingot (the master alloy ingot prepared here has uneven composition distribution and component segregation).

[0110] The raw materials are weighed according to the target alloy composition, and the corresponding weight of the intermediate alloy ingot is cut. The principle of using the intermediate alloy is that the calculated Co, Re and Al contents do not exceed the upper limit of the target alloy.

[0111] 2) The first raw material is loaded into the crucible in the order of C, Cr, Ni, W, Co, Mo, Nb, and Ta, and vacuum smelting is performed. When the vacuum degree is <5Pa, power melting is started (power melting is to supply power to the vacuum induction furnace to melt the raw materials in the crucible). At a temperature of 1550°C, alloying and refining treatment is performed for 20 minutes, and then the temperature is lowered to 1400°C, and the prepared Re-Al-Co master alloy is added to the melt for homogenization treatment (i.e., secondary alloying), and the temperature is kept for 30 minutes (i.e., homogenization treatment for 30 minutes), and then single Al is added for homogenization treatment to obtain a homogenized alloy liquid.

[0112] 3) The alloy liquid after homogenization treatment is heated to 1460° C. and poured to obtain a nickel-based high-temperature alloy with a high Re content.

[0113] The chemical composition of the upper and lower parts of the high Re content nickel-based high temperature alloy prepared in this comparative example was tested and analyzed (i.e., samples were taken near the head and tail ends of the rod-shaped alloy ingot of this embodiment) to examine the uniformity of the alloy composition. The test results are shown in Table 8. From Table 8, it can be seen that in the chemical composition control, the mass fraction difference of the Re element at the upper and lower ends of the alloy is large, the element distribution is uneven, and there is element segregation in the alloy.

[0114] Table 8 Chemical composition of the upper and lower parts of the high Re content nickel-based high-temperature alloy prepared in this comparative example (mass fraction, wt%)

[0115]

[0116] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a nickel-based high-temperature alloy with a high Re content, characterized in that: The Re content of the high Re content nickel-based high-temperature alloy is 3.3-4.5 wt %; wherein the preparation method comprises the following steps: Raw material preparation step: preparing a first raw material and a second raw material; wherein the elements provided by the first raw material include C, Cr, Ni, W, Co, Mo, Nb, and Ta; and the second raw material includes: a rhenium-aluminum-cobalt master alloy and a single substance Al for providing Re, Al, and Co elements; Vacuum melting step: firstly, melting and alloying and refining the first raw material; then, lowering the temperature of the melt to a homogenization temperature, adding the rhenium-aluminum-cobalt master alloy to the melt for homogenization, and then adding single Al to the melt for homogenization to obtain a homogenized alloy liquid; Pouring step: pouring the alloy liquid after the homogenization treatment to obtain a nickel-based high-temperature alloy with a high Re content.

2. The method for preparing a nickel-based high-temperature alloy with a high Re content according to claim 1, characterized in that: In the rhenium-aluminum-cobalt master alloy, the mass fraction of Re is 15-40wt%, the mass fraction of Al is 10-35wt%, and Co is the balance.

3. The method for preparing a nickel-based high-temperature alloy with a high Re content according to claim 2, characterized in that: The preparation steps of the rhenium-aluminum-cobalt master alloy include: The method comprises the following steps: smelting and purifying single substance cobalt to obtain a cobalt melt; adding single substance rhenium to the cobalt melt to perform a first alloying treatment; when the melt after the first alloying treatment is cooled to a temperature 30 to 50° C. higher than the liquidus line of the melt, adding single substance aluminum to the melt to perform a second alloying treatment; homogenizing the melt after the second alloying treatment; and pouring the homogenized melt to obtain a rhenium-aluminum-cobalt master alloy; Preferably, the temperature of the first alloying treatment is 1550-1600°C, and the time of the first alloying treatment is 10-30 minutes; Preferably, the temperature of the second alloying treatment is 1500-1550°C, and the time of the second alloying treatment is 10-30 minutes; Preferably, the temperature of the homogenization treatment is 50-60° C. higher than the liquidus temperature of the desired rhenium-aluminum-cobalt master alloy; Preferably, the homogenization treatment time is 10 to 15 minutes; Preferably, the pouring temperature is 10-20°C higher than the homogenization temperature; Preferably, the content ratio of each element in the rhenium-aluminum-cobalt master alloy is determined according to the mass fraction of rhenium, aluminum and cobalt in the high Re content nickel-based high-temperature alloy; according to the content ratio of each element in the rhenium-aluminum-cobalt master alloy, elemental rhenium, elemental aluminum and elemental cobalt are weighed; further preferably, the weighed elemental rhenium and elemental aluminum are respectively wrapped with aluminum foil.

4. The method for preparing a nickel-based high-temperature alloy with a high Re content according to any one of claims 1 to 3, characterized in that: The high Re content nickel-based high temperature alloy comprises the following chemical components in terms of weight percentage: Cr 4.0~6.0wt%, Al 5.5~6.5wt%, Co 8~10wt%, Mo 0.5~1.5wt%, Nb1.5~1.8wt%, W 8.0~9.5wt%, Ta 3.5~4.5wt%, Re 3.3~4.5wt%, C 0.10~0.20wt%, and the rest is Ni; Preferably, in the nickel-based high-temperature alloy with high Re content, the weight percentage of impurities meets the following requirements: O≤5ppm, N≤5ppm, S≤5ppm.

5. The method for preparing a nickel-based high-temperature alloy with a high Re content according to claim 4, characterized in that: In the high Re content nickel-based high temperature alloy: The ratio of the weight percentage of the Re element to the weight percentage of the Al element is set to 1.0-3.0; the sum of the weight percentage of the Re element and the weight percentage of the Al element is 35-70wt%.

6. The method for preparing a nickel-based high-temperature alloy with a high Re content according to any one of claims 1 to 5, characterized in that: In the vacuum melting step: First, the first raw material is loaded into a melting crucible in the order of C, Cr, Ni, W, Co, Mo, Nb, and Ta, and is melted, alloyed, and refined. After the raw material is completely refined, the rhenium-aluminum-cobalt master alloy is added thereto for homogenization. Then, single Al is added to the melt for homogenization to obtain a homogenized alloy liquid.

7. The method for preparing a nickel-based high-temperature alloy with a high Re content according to any one of claims 1 to 6, characterized in that: In the vacuum melting step: The first raw material is placed in a crucible for vacuum melting. When the vacuum degree is less than 5 Pa, electric melting is started. At 1550-1600° C., alloying refining is performed. Then, the temperature of the melt is lowered to 1400-1450° C., and the rhenium-aluminum-cobalt master alloy is added thereto for homogenization treatment. Then, single Al is added to the melt for homogenization treatment to obtain a homogenized alloy liquid. Preferably, the alloying refining treatment time is 20-30 minutes; Preferably, the time for adding the rhenium-aluminum-cobalt master alloy and performing homogenization treatment is 30-40 minutes; Preferably, when the homogenization treatment is performed, electromagnetic stirring treatment is required; further preferably, the electromagnetic stirring treatment time is 10-15 minutes; Preferably, the homogenization treatment is performed for 10-15 minutes after adding the elemental Al.

8. The method for preparing a nickel-based high-temperature alloy with a high Re content according to any one of claims 1 to 7, characterized in that: In the pouring step: the alloy liquid after the homogenization treatment is heated to a temperature 70-100° C. higher than the liquidus line of the alloy liquid after the homogenization treatment, and then the pouring treatment is performed to obtain a nickel-based high-temperature alloy with a high Re content.

9. A nickel-based high-temperature alloy with a high Re content, characterized in that: The high-Re content nickel-based high-temperature alloy is prepared by the preparation method of the high-Re content nickel-based high-temperature alloy according to any one of claims 1 to 8; Preferably, in the as-cast structure of the high-Re content nickel-based high-temperature alloy, the primary dendrite spacing is 0.3 to 0.4 mm; preferably, the primary dendrites are evenly distributed.

10. A nickel-based single crystal high-temperature alloy with a high Re content, characterized in that: The steps for preparing the nickel-based single crystal high-temperature alloy with a high Re content include: 1) A high-Re content nickel-based high-temperature alloy is prepared by using the preparation method of the high-Re content nickel-based high-temperature alloy according to any one of claims 1 to 8; 2) The high Re content nickel-based high temperature alloy is prepared into a high Re content nickel-based single crystal high temperature alloy.

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