A method of plasticizing and breaking down a wrought superalloy

Abstract

The application relates to a plasticizing and blooming method of a deformed high-temperature alloy, which comprises the following steps: solid solution treatment of a deformed high-temperature alloy ingot at a temperature of T m +(10-40 DEG C) for 8-20 hours, then increasing the temperature to T m +(40-70 DEG C) for 16-30 hours; cooling the homogenized ingot to T m below at a set cooling rate; keeping the cooled ingot at a temperature of T m -(10-60 DEG C) for 10-72 hours to coarsen the size of part of the gamma prime phase in the deformed high-temperature alloy to micron level; and blooming and forging the ingot after the coarsened gamma prime phase treatment to obtain a plasticized and bloomed deformed high-temperature alloy. The application can effectively improve the hot plasticity of the difficult-to-deform high-temperature alloy, reduce the deformation resistance, improve the material yield of the alloy, improve the uniformity of the structure and performance of the alloy, and provide a guarantee for safe preparation of the high-temperature capacity deformed high-temperature alloy. The application has the advantages of simple operation, low cost, simplified steps, low dependence on equipment, and can be used to prepare the difficult-to-deform high-temperature alloy on the existing hydraulic machine tooling.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wrought superalloys, and particularly relates to a plasticizing cogging method of wrought superalloys. BACKGROUND

[0002] With the progress of science and technology, the aero-engine is developing towards high thrust-to-weight ratio and high efficiency, and the comprehensive performance requirements of the superalloy for the aero-engine are also getting higher and higher. In order to improve the temperature resistance of the wrought superalloy, one of the most effective methods is to increase the content of γ' phase in the alloy. For example, GH4169 (In718) alloy is strengthened by γ' phase, and the temperature resistance is 650℃, and GH4169D (In718Plus) with a temperature resistance of 700℃ is strengthened by 22-27wt% of γ' phase. The temperature resistance of GH4738 (Waspaloy), GH4065 (René88DT), GH4720Li (U720Li), GH4068 and GH4151 and other alloys is getting higher and higher, gradually reaching 800℃, and the content of γ' phase in the alloy is also more than 50wt%. These high content of γ' phase increases the deformation resistance of the alloy and significantly deteriorates the hot plasticity, which is not conducive to the cogging forging of the alloy and seriously restricts the preparation and application of these high temperature resistance alloys.

[0003] The three-directional compressive stress in the hot extrusion cogging process can improve the hot plasticity of the alloy, but the deformation resistance of the difficult-to-deform alloy is large, and the extrusion stagnation phenomenon often occurs, and the strip-shaped structure along the extrusion direction often appears in the extrusion cogged bar, which affects the service life of the alloy. The multi-pass upsetting and drawing cogging can make the alloy have uniform deformation structure, but the grains of the difficult-to-deform superalloy are coarse, and the grains contain a high volume fraction of nano-sized γ' phase. These microstructure characteristics make the billet directly crack in the upsetting and drawing process without deformation.

[0004] Although cogging above the γ' phase solid solution temperature (over-solution temperature) can reduce the strengthening effect of γ' phase and promote the recrystallization of the matrix to improve the hot plasticity of the alloy. However, cogging at the over-solution temperature lacks pinning of precipitated phases, and the grains are prone to abnormal growth, which is not conducive to the subsequent disc forming and heat treatment performance control.

[0005] In summary, there is an urgent need for a plasticizing cogging method that can effectively improve the hot plasticity of the difficult-to-deform superalloy, reduce the deformation resistance, improve the yield of the alloy, and improve the uniformity of the microstructure and performance of the alloy. SUMMARY

[0006] In view of the above, the present application provides a plasticizing and blooming method for deforming high-temperature alloy, mainly aiming at effectively improving the thermal plasticity of the difficult-to-deform high-temperature alloy, reducing the deformation resistance, improving the material yield of the alloy, and improving the uniformity of the structure and performance of the alloy.

[0007] To achieve the above-mentioned purposes, the present application mainly provides the following technical solutions:

[0008] In one aspect, the embodiment of the present application provides a plasticizing and blooming method for deforming high-temperature alloy, comprising the following steps:

[0009] Homogenization treatment: the deformed high-temperature alloy ingot is subjected to solid solution treatment at a temperature of T m +(10-40℃) for 8-20h, and then is heated to T m +(40-70℃) for solid solution treatment for 16-30h to obtain the homogenization treated ingot; wherein, T m is the complete re-dissolution temperature of the γ' phase of the deformed high-temperature alloy;

[0010] Cooling treatment: the homogenization treated ingot is cooled to a first temperature at a set cooling rate; to obtain the cooled ingot; wherein, the set cooling rate is used to reduce the nucleation rate of the γ' phase, so that the γ' phase in the matrix is supersaturated and the γ' phase forming elements in the matrix are supersaturated; wherein, the first temperature is not higher than T m , preferably T m -(10-60℃);

[0011] Coarse γ' phase treatment: the cooled ingot is kept at a second temperature for 10-72h to coarsen the size of part of the γ' phase in the deformed high-temperature alloy to micron level, to obtain the coarse γ' phase treated ingot; wherein, the second temperature is T m -(10-60℃);

[0012] Blooming and forging treatment: the coarse γ' phase treated ingot is subjected to blooming and forging treatment to obtain the plasticized and bloomed deformed high-temperature alloy.

[0013] Preferably, in the step of the blooming and forging treatment: the coarse γ' phase treated ingot is subjected to multiple upsetting and drawing; wherein, the strain of the first fire is 30-50%; with the increase of the fire, the strain increases by no less than 10%; the final forging temperature of each fire is ≥ T m -(60-100℃).

[0014] Preferably, the content of the γ' phase in the deformed high-temperature alloy is higher than 20wt%.

[0015] Preferably, the deformed high-temperature alloy is any one of GH4738, GH4065, GH4720Li, GH4068, and GH4151.

[0016] Preferably, before the homogenization step, the method further includes spraying an antioxidant on the surface of the deformed high-temperature alloy ingot; wherein the antioxidant can form a molten glass on the surface of the deformed high-temperature alloy ingot after reaching the solid solution temperature, so as to prevent the deformed high-temperature alloy ingot from contacting with air and avoiding high-temperature oxidation.

[0017] Preferably, in the cooling treatment step: the cooling rate is set to 5 to 50° C. / h.

[0018] Preferably, in the cooling treatment step: by controlling the cooling rate to a set cooling rate, the nucleation rate of the γ′ phase is reduced, so that the γ′ phase first nucleates at the grain boundary to form a granular, discontinuous, micron-sized γ′ phase.

[0019] Preferably, at the grain boundaries of the deformed high-temperature alloy after plasticization and blanking, more than 80% of the γ′ phases are in the micron size range.

[0020] Preferably, in the deformed high-temperature alloy after plasticization and blanking, the content of γ′ phase with a size of ≥1 μm is 10-50 wt%.

[0021] Preferably, the grain size of the deformed high-temperature alloy after plasticization and blanking is higher than grade 8.

[0022] Preferably, the deformed high temperature alloy after plasticization is heated to 1000℃ / 10 -2 s -1 The tensile elongation under the conditions is ≥300%, and the maximum deformation resistance is ≤400MPa.

[0023] On the other hand, the present invention provides a deformed high-temperature alloy after plasticizing and blanking, wherein the deformed high-temperature alloy after plasticizing and blanking has a γ′ phase content of 1 μm or larger and a grain size of higher than 8 grades; and the deformed high-temperature alloy after plasticizing and blanking has a 1000°C / 10 -2 s -1 The tensile elongation under the conditions is ≥300%, and the maximum deformation resistance is ≤400 MPa; preferably, at the grain boundaries of the deformed high-temperature alloy after plasticizing and blanking, more than 80% of the γ′ phase is micron-sized; preferably, the deformed high-temperature alloy after plasticizing and blanking is prepared by the plasticizing and blanking method of deformed high-temperature alloy described in any one of the above.

[0024] Compared with the prior art, the plasticizing and blanking method of a deformed high-temperature alloy of the present invention has at least the following beneficial effects:

[0025] The application provides a plasticizing and blooming method of deformed high-temperature alloy, mainly comprising the following steps: solid-solution treating a deformed high-temperature alloy ingot at a temperature of T m +(10-40℃) for 8-20 hours, then increasing the temperature to T m +(40-70℃) for 16-30 hours to obtain an ingot after homogenization treatment; wherein, T m is a complete re-dissolution temperature of γ' phase of the deformed high-temperature alloy; cooling the ingot after homogenization treatment to T m below at a set cooling rate to obtain an ingot after cooling treatment; wherein, the set cooling rate is used to reduce the nucleation rate of γ' phase, so that the γ' phase in the matrix is supersaturated and the forming elements of the γ' phase in the matrix are supersaturated; cooling the ingot after cooling treatment to T m -(10-60℃) and keeping the temperature for 10-72 hours to make the size of part of the γ' phase in the deformed high-temperature alloy coarsen to micron level, and obtain an ingot after γ' phase coarsening treatment; performing blooming forging treatment on the ingot after γ' phase coarsening treatment to obtain the deformed high-temperature alloy after plasticizing and blooming.

[0026] Firstly, the deformed high-temperature alloy ingot is solid-solution treated at T m +(10-40℃) for 8-20 hours to eliminate the low-melting-point phase of the alloy and prevent the low-melting-point phase from melting to form holes due to too high temperature; then the temperature is continuously increased to T m +(40-70℃) for 16-30 hours to eliminate the dendritic structure and harmful precipitated phase in the ingot and make the elements in the alloy uniformly diffuse.

[0027] In this application, two-step homogenization treatment is performed to make the alloy elements uniformly distributed, which is beneficial to more uniform γ' phase precipitation and coarsening in the subsequent treatment process.

[0028] Secondly, the ingot after homogenization treatment is cooled to T m below at a cooling rate of 5-50℃ / h, while the ingot after conventional homogenization is cooled in the furnace (the cooling rate is ≥60℃ / h); the application reduces the nucleation rate of γ' phase by reducing the cooling rate, so that the γ' phase is firstly nucleated at the grain boundary to strengthen the grain boundary and reduce the tendency of the alloy to produce intergranular cracking in the subsequent blooming process.

[0029] Thirdly, the blank is cooled to T m -(10-60℃) and kept for 10-72 hours; since the slow cooling reduces the nucleation rate of γ' phase, the forming elements of the γ' phase in the matrix are in a supersaturated state, and the γ' phase firstly precipitated during the keeping process grows and coarsens, and the size of the coarsened γ' phase is above 1 μm.

[0030] Detailed description as follows: after the step of cooling treatment, the gamma prime phase in the alloy is coarsened to a certain extent, but still hinders dislocation movement, and is not enough to provide nucleation points for the recrystallization of the matrix, and needs to be further coarsened. After the gamma prime phase is coarsened to a micron level, the hindering effect of the gamma prime phase on dislocations is reduced or even eliminated, and the recrystallization of the matrix is provided with sufficient nucleation points, the already refined grains are inhibited from coarsening and growing, and the fine grains are maintained.

[0031] Fourth, the cogging forging treatment is performed at T m below, the preparation working condition requirement is reduced, and since the recrystallization degree gradually increases, the deformation amount is gradually increased with the increase of the fire, the return temperature of each fire is consistent, the temperature does not need to be reduced, the operation is simple, and after repeated upsetting and drawing deformation, uniform fine grain structure rod is finally obtained, the grain size is above 8 levels, the fine grain structure makes the difficult-to-deform superplastic high-temperature alloy appear, the superplasticity characteristics are small deformation resistance, high thermal plasticity and the obtained structure is still uniform and fine, all of which are beneficial to subsequent die forging forming and heat treatment performance control.

[0032] In summary, the plasticizing cogging method of the deformed high-temperature alloy provided by the present application can effectively improve the thermal plasticity of the difficult-to-deform high-temperature alloy, reduce the deformation resistance, improve the yield of the alloy, and improve the uniformity of the structure and performance of the alloy, thereby providing protection for the safe preparation of the high-temperature capacity deformed high-temperature alloy. In addition, the method of the present application is simple to operate, low in cost, simple in steps, and low in dependence on equipment, and can be used to prepare the difficult-to-deform high-temperature alloy on the existing hydraulic machine tooling.

[0033] The above description is only a summary of the technical solutions of the present application, in order to more clearly understand the technical means of the present application, and can be implemented according to the content of the specification, the following is a preferred embodiment of the present application and the detailed description is as follows. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 The microstructure photograph of the cast ingot after the coarsening gamma prime phase treatment in the method of the present application.

[0035] Figure 2 The microstructure photograph of the deformed high-temperature alloy after the plasticizing cogging of example 1.

[0036] Figure 3 The microstructure photograph of the deformed high-temperature alloy after the plasticizing cogging of example 2.

[0037] Figure 4 The microstructure photograph of the deformed high-temperature alloy after the plasticizing cogging of example 3.

[0038] Figure 5 The microstructure photograph of the deformed high-temperature alloy after the plasticizing cogging of example 4.

[0039] Figure 6 Microstructure photograph of the alloy after the method described in Comparative Example 1.

[0040] Figure 7 Microstructure photograph of the alloy after the method described in Comparative Example 2.

[0041] Figure 8 Microstructure photograph of the alloy after the method described in Comparative Example 3.

[0042] Figure 9 Microstructure photograph of the alloy after the method described in Comparative Example 4. DETAILED DESCRIPTION

[0043] To further illustrate the technical means and effects taken by the present application to achieve the intended object, the following describes the specific embodiments, structures, features and effects according to the present application in detail in combination with the accompanying drawings and preferred embodiments. In the following description, different "an embodiment" or "embodiments" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0044] It should be noted that the breakdown below the γ' phase solid solution temperature (sub-solid solution temperature) is the breakdown temperature established by the present application. The deformation at the sub-solid solution temperature must eliminate the adverse effects of the thermal plasticity of the γ' phase and promote the recrystallization of the matrix to obtain uniform fine-grained rod materials.

[0045] The present application uses temperature control and deformation methods to first eliminate the solidification segregation in the billet, making the element distribution of the alloy uniform. Then, by controlling the cooling method, the nucleation rate of the γ' phase is reduced, and part of the γ' phase nucleates at the grain boundaries first. Then, through the heat preservation treatment, the nanoscale γ' phase in the alloy is coarsened across the scale to the micron level, reducing or even eliminating the precipitation strengthening effect of the γ' phase, and providing sufficient nucleation sites for the recrystallization of the matrix. The already refined grains are inhibited from growing and coarsening again in the high-temperature environment of deformation and re-melting and heat preservation. Finally, through repeated upsetting and drawing deformation, the alloy obtains a uniform fine-grained structure.

[0046] The present application is realized by the following technical solutions:

[0047] 1) Homogenization treatment: the deformed superalloy ingot is subjected to solid solution treatment at a temperature of T m +(10-40℃) for 8-20h, and then is heated to T m +(40-70℃) for 16-30h to obtain the homogenized ingot; wherein, T m is the complete solid solution temperature of the γ' phase of the deformed superalloy (T mDifferent, T m can be measured by conventional technical means.

[0048] 2) cooling treatment: cooling the homogenized ingot to a first temperature at a set cooling rate to obtain a cooled ingot; wherein the set cooling rate is used to reduce the nucleation rate of γ' phase, so that the γ' phase in the matrix is supersaturated, and the γ' phase forming elements in the matrix are supersaturated; wherein the first temperature is not higher than T m ;

[0049] The set cooling rate is 5-50℃ / h. By controlling the cooling rate, the γ' phase is first nucleated at the grain boundary to form granular non-continuous micron-sized γ' phase, strengthening the grain boundary and solving the problem of grain boundary cracking in the subsequent breakdown process.

[0050] 3) γ' phase coarsening treatment: the cooled ingot is kept at a second temperature for 10-72h to coarsen the size of part of the γ' phase in the deformed superalloy to micron level, to obtain a γ' phase coarsened ingot; wherein the second temperature is T m -(10-60℃);

[0051] 4) breakdown forging treatment: the γ' phase coarsened ingot is subjected to breakdown forging treatment to obtain a plasticized and broken down deformed superalloy.

[0052] The step is specifically: the billet containing coarse γ' phase is subjected to multiple upsetting and drawing, the strain of the first heating is 30-50%, and the strain can be increased by no less than 10% with the increase of heating times, and the final forging temperature of each heating is ≥Tm-(60-100℃). It should be noted that the final forging temperature refers to the temperature of the last forging; the final forging temperature is controlled to prevent the alloy from being too low in plasticity and causing cracking problems.

[0053] Here, regarding the above steps, it should be noted that:

[0054] 1) The deformed superalloy with high temperature capacity to which the treatment method is applied includes but is not limited to GH4738 (Waspaloy), GH4065 (René88DT), GH4720Li (U720Li), GH4068 and GH4151 alloy. First, the deformed superalloy ingot is subjected to solid solution treatment at T m +(10-40℃) for 8-20h (T m is the complete solid solution temperature of the γ' phase in the alloy) to eliminate low melting point phases in the alloy and prevent the low melting point phases from melting to form pores due to too high temperature; then continue to heat to T m+ (40 ~ 70 ℃) for 16 ~ 30h to eliminate the dendrite structure and harmful precipitation phase in the ingot and make the elements in the alloy diffuse evenly. Then, the ingot after homogenization treatment is cooled to T at 5 ~ 50 ℃ / h. m Temperature below, while conventional homogenization is followed by furnace cooling to room temperature (cooling rate ≥ 60℃ / h), the present invention reduces the nucleation rate of γ′ phase by reducing the cooling rate, so that γ′ phase is first nucleated at the grain boundary, which strengthens the grain boundary and reduces the tendency of the alloy to crack along the grain during the subsequent blanking process. m -(10~60℃) temperature for 10~72h. Due to the slow cooling, the nucleation rate of γ′ phase is reduced, so that the γ′ phase forming elements in the matrix are in a supersaturated state. The γ′ phase that precipitates first in the heat preservation process grows and coarsens. The size of the coarsened γ′ phase is above 1μm. The billet containing coarse γ′ phase is taken out of the furnace and upsetting is performed. The strain of the first fire is 30~50%. As the number of fires increases, the strain can be increased by 5~10%. The final forging temperature of each fire is ≥T m -(60~100℃), the number of upsetting and drawing passes is greater than 3 times.

[0055] 2) Compared with the existing technology, the existing technology is generally in T m When hot working is performed above this temperature, due to the lack of dynamic recrystallization nucleation sites, new recrystallized grains can only nucleate at grain boundaries, resulting in coarse grain sizes below level 6, and even the appearance of a large amount of mixed crystal structure. This coarse grain structure still has low thermoplasticity in the bar, which is not conducive to further forming and heat treatment performance control of parts. The present invention, without changing the alloying degree of the material, uses heat treatment and deformation control to coarsen the high-content nanoscale γ′ phase to the micron level across scales, with a few steps, easy operation, no pollution, and low cost. This reduces deformation resistance and improves the degree of recrystallization, turning unfavorable factors for thermoplasticity into favorable factors.

[0056] 3) The homogenization treatment in the steps of the present invention takes into account the influence of the low melting point relative to the thermoplasticity of the alloy, and performs a two-step homogenization treatment to make the alloy elements evenly distributed, which is conducive to more uniform precipitation and coarsening of the γ′ phase in the subsequent treatment process. The cooling treatment is controlled to form the γ′ phase at the grain boundaries of the coarse grains in the cast alloy, thereby preventing serious production accidents such as direct breakage of the billet due to intergranular cracking during the blanking process due to weakening of the grain boundaries, and significantly improving the yield of the alloy. After the controlled cooling treatment, although the γ′ phase in the alloy is coarsened to a certain extent, it still hinders the movement of dislocations and is not enough to provide nucleation points for the recrystallization of the matrix. It is necessary to further coarsen the γ′ phase. After the γ′ phase is coarsened to the micron level across scales, the hindering effect of the γ′ relative dislocation is reduced or even eliminated. At the same time, the coarse γ′ phase provides sufficient nucleation points for the recrystallization of the matrix, inhibiting the coarsening and growth of the already refined grains and keeping them small. The blanking forging treatment is carried out at Tm The forging is carried out at a temperature below, the preparation working condition requirement is reduced, and the deformation amount is gradually increased with the increase of the fire times due to the gradual increase of the recrystallization degree, the return-to-furnace temperature of each fire time is consistent, the temperature does not need to be reduced, the operation is simple, and finally the uniform fine-grained rod is obtained through repeated upsetting and drawing deformation, the grain size is above 8 levels, the fine-grained structure makes the difficult-to-deform high-temperature alloy exhibit superplasticity, the superplasticity features are small deformation resistance, high thermal plasticity and the obtained structure is still uniform and fine, all of which are beneficial to subsequent die forging forming and heat treatment performance control.

[0057] 4) The present application utilizes heat treatment and deformation means to induce γ' phase coarsening, as shown in Figure 1 The non-continuous granular γ' phase is generated at the coarse matrix grain boundary, the grain boundary is strengthened to achieve the purpose of improving the thermal plasticity of the high-difficult-to-deform high-temperature alloy. After the alloy is formed and prepared, the coarse γ' phase can be re-dissolved through heat treatment, and the matrix grain size can be controlled, so that the alloy still has excellent mechanical properties, the whole process has few steps and simple operation; meanwhile, the process is a combination of traditional processing means, and most importantly, since no other alloy elements are added, the inherent properties of the alloy are not changed, so the purpose of optimizing the performance of the alloy is achieved almost without increasing the cost of the alloy.

[0058] The present application is further illustrated by the following specific experimental examples:

[0059] In the embodiment of the present application, the cast ingot is subjected to solution treatment at T m +(10-40℃) for 8-20h (T m is the complete γ' phase solid solution temperature in the alloy), and then is subjected to solution treatment at T m +(40-70℃) for 16-30h; the cast ingot after homogenization treatment is cooled to T m -(10-60℃) at a cooling rate of 5-50℃ / h, and is kept at the temperature for 10-72h to make the γ' phase coarsen to micron level; the blank containing the coarse γ' phase is subjected to multi-fire upsetting and drawing, the strain of the first fire is 30-50%, and the strain amount is increased by more than 10% with the increase of the fire times, and the final forging temperature of each fire is ≥T m -(60-100℃). The alloy microstructure is observed by using Leica DM4M metallographic microscope, and the high-temperature plasticity and strength of the alloy are tested by using INSTRON 5582 single-axis tensile testing machine.

[0060] Example 1

[0061] The embodiment provides a plasticizing blooming method of GH4065A alloy, which comprises the following steps,

[0062] 1) homogenization treatment: the ingot is treated at a temperature of 1150℃ for 15h, and then heated to 1180℃ for 25h to obtain the homogenized ingot. Among them, the T m temperature is 1110℃.

[0063] 2) cooling treatment: the homogenized ingot is cooled to 1070℃ at a cooling rate of 30℃ / h to obtain the cooled ingot.

[0064] 3) γ' phase coarsening treatment: the cooled ingot is treated at a temperature of 1070℃ for 25h to coarsen the γ' phase to micron level, and the average particle size is 3μm, to obtain the γ' phase coarsened ingot.

[0065] 4) open-die forging treatment: the γ' phase coarsened ingot is subjected to 5 times of upsetting and drawing to obtain the plasticized open-die deformed superalloy. Among them, the first fire strain is 40%, the second fire strain is 50%, the third fire strain is 75%, the fourth fire strain is 120%, and the fifth fire strain is 200%, and the final forging temperature of each fire is ≥1020℃.

[0066] The microstructure of the plasticized open-die deformed superalloy of the present embodiment is shown in Figure 2 It can be seen from Figure 2 that the plasticized open-die deformed superalloy of the present embodiment contains γ' phase with a content of 30wt% and a matrix grain size of 11 levels.

[0067] In addition, the high-temperature tensile properties of the plasticized open-die deformed superalloy of the present embodiment are shown in Table 1, and the tensile strength at 1000℃ is 100MPa and the elongation is 1200%.

[0068] Example 2

[0069] The present embodiment provides a plasticizing open-die method for GH4720Li alloy, comprising the following steps,

[0070] 1) homogenization treatment: the ingot is treated at a temperature of 1150℃ for 15h, and then heated to 1180℃ for 25h to obtain the homogenized ingot. Among them, the T m temperature is 1110℃.

[0071] 2) cooling treatment: the homogenized ingot is cooled to 1070℃ at a cooling rate of 30℃ / h to obtain the cooled ingot.

[0072] 3) Coarsening γ′ phase treatment: The cooled ingot was kept at 1090° C. for 20 h to coarsen the γ′ phase to the micron level with an average particle size of 4 μm, thereby obtaining an ingot after coarsening γ′ phase treatment.

[0073] 4) Cogging and Forging: The ingot, after coarsening the γ′ phase, is subjected to six upsetting cycles to obtain a deformed high-temperature alloy after plasticized cogging. The strain in the first cycle is 30%, the strain in the second cycle is 45%, the strain in the third cycle is 70%, the strain in the fourth cycle is 100%, the strain in the fifth cycle is 150%, and the strain in the sixth cycle is 220%. The final forging temperature in each cycle is ≥1050°C.

[0074] The microstructure of the deformed high temperature alloy after plasticizing and blanking in this embodiment is as follows: Figure 3 As shown. Figure 3 It can be seen that the deformed high-temperature alloy after plasticization and blanking in this embodiment contains 35 wt% of the γ′ phase with a size of ≥1 μm, and the matrix grain size is level 10.

[0075] In addition, the high temperature tensile properties of the deformed high temperature alloy after plasticization and blanking in this embodiment are shown in Table 1. The tensile strength at 1000° C. is 230 MPa and the elongation is 900%.

[0076] Example 3

[0077] The present invention provides a method for plasticizing and opening a GH4068 alloy, comprising the following steps:

[0078] 1) Homogenization treatment: The ingot was held at 1160°C for 16 hours, then heated to 1190°C for 26 hours to obtain a homogenized ingot. The Tm temperature of the GH4068 alloy was found to be 1141°C.

[0079] 2) Cooling treatment: The homogenized ingot is cooled to 1080° C. at a cooling rate of 50° C. / h to obtain a cooled ingot.

[0080] 3) Coarsening γ′ phase treatment: The cooled ingot was kept at 1090° C. for 24 h to coarsen the γ′ phase to the micron level with an average particle size of 4 μm, thereby obtaining an ingot after coarsening γ′ phase treatment.

[0081] 4) Cogging and Forging: The ingot, after coarsening the γ′ phase, is subjected to five upsetting cycles to obtain a deformed high-temperature alloy after plasticized cogging. The strain in the first cycle is 35%, the strain in the second cycle is 50%, the strain in the third cycle is 80%, the strain in the fourth cycle is 150%, and the strain in the fifth cycle is 240%. The final forging temperature in each cycle is ≥1041°C.

[0082] The microstructure of the deformed high-temperature alloy after plastic breakdown in this embodiment is shown in Figure 4 As can be seen from Figure 4 It can be seen that the deformed high-temperature alloy after plastic breakdown in this embodiment contains γ' phase with a size of ≥1 μm, and the content of the γ' phase is 32wt%, and the matrix grain size is 9 levels.

[0083] In addition, the high-temperature tensile properties of the deformed high-temperature alloy after plastic breakdown in this embodiment are shown in Table 1, and the tensile strength at 1000℃ is 150MPa, and the elongation is 1150%.

[0084] Example 4

[0085] The application provides a plastic breakdown method of GH4151 alloy, comprising the following steps,

[0086] 1) homogenization treatment: the ingot is treated at a temperature of 1170℃ for 16h, and then heated to 1200℃ for 20h to obtain the homogenized ingot. It is tested that the Tm temperature of the GH4151 alloy is 1160℃.

[0087] 2) cooling treatment: the homogenized ingot is cooled to 1110℃ at a cooling rate of 40℃ / h to obtain the cooled ingot.

[0088] 3) γ' phase coarsening treatment: the cooled ingot is kept at 1110℃ for 25h to coarsen the γ' phase to micron level, and the average particle size is 5μm, to obtain the γ' phase coarsened ingot;

[0089] 4) breakdown forging treatment: the γ' phase coarsened ingot is subjected to 8 times of upsetting and drawing to obtain the deformed high-temperature alloy after plastic breakdown. The strain of the first time is 30%, the strain of the second time is 40%, the strain of the third time is 55%, the strain of the fourth time is 120%, the strain of the fifth time is 150%, the strain of the sixth time is 180%, the strain of the seventh time is 200%, and the strain of the eighth time is 220%, and the final forging temperature of each time is ≥1060℃.

[0090] The microstructure of the deformed high-temperature alloy after plastic breakdown in this embodiment is shown in Figure 5 As can be seen from Figure 5 It can be seen that the deformed high-temperature alloy after plastic breakdown in this embodiment contains γ' phase with a size of ≥1 μm, and the content of the γ' phase is 32wt%, and the matrix grain size is 9 levels.

[0091] In addition, the high-temperature tensile properties of the deformed high-temperature alloy after plastic breakdown in this embodiment are shown in Table 1, and the tensile strength at 1000℃ is 150MPa, and the elongation is 1150%.

[0092] Comparative Example 1

[0093] Comparative Example 1

[0094] 1) Homogenization treatment: the ingot was solution treated at 1170℃ for 30h, and furnace-cooled to 400℃ and discharged, to obtain the homogenized ingot;

[0095] 2) The homogenized ingot was heated to 1100℃ for forging, to obtain the deformed high-temperature alloy after breakdown. The strain of the first heating was 20%, the strain of the second heating was 30%, the strain of the third heating was 40%, the strain of the fourth heating was 50%, the strain of the fifth heating was 60%, the strain of the sixth heating was 70%, the strain of the seventh heating was 85%, the strain of the eighth heating was 100%, and the final forging temperature of each heating was ≥1050℃.

[0096] The microstructure of the deformed high-temperature alloy after breakdown of Comparative Example 1 is shown in FIG. 1. As can be seen from FIG. 1, the deformed high-temperature alloy after breakdown of Comparative Example 1 had no micron-sized γ' phase, and the matrix grain size was 4 levels. Figure 6 Figure 6 In addition, the high-temperature tensile properties of the deformed high-temperature alloy after breakdown of Comparative Example 1 are shown in Table 1, and the tensile strength at 1000℃ was 460MPa, and the elongation was 28%.

[0097] Comparative Example 2

[0098] Comparative Example 2

[0099] Comparative Example 2

[0100] 1) Homogenization treatment: the ingot was solution treated at 1180℃ for 40h, and furnace-cooled to 400℃ and discharged, to obtain the homogenized ingot;

[0101] 2) The homogenized ingot was heated to 1120℃ for forging, to obtain the deformed high-temperature alloy after breakdown. The strain of the first heating was 20%, the strain of the second heating was 30%, the strain of the third heating was 30%, the strain of the fourth heating was 40%, the strain of the fifth heating was 50%, the strain of the sixth heating was 60%, the strain of the seventh heating was 80%, the strain of the eighth heating was 90%, the strain of the ninth heating was 100%, and the final forging temperature of each heating was ≥1060℃.

[0102] The microstructure of the deformed high-temperature alloy after breakdown of Comparative Example 2 is shown in FIG. 2. As can be seen from FIG. 2, the deformed high-temperature alloy after breakdown of Comparative Example 2 had no micron-sized γ' phase, and the matrix grain size was 4 levels. Figure 7 Figure 7 In addition, the high-temperature tensile properties of the deformed high-temperature alloy after breakdown of Comparative Example 2 are shown in Table 1, and the tensile strength at 1000℃ was 460MPa, and the elongation was 28%.

[0103] ​​In addition, the high-temperature tensile properties of the wrought superalloy after breakdown of Comparative Example 2 are shown in Table 1, and the tensile strength at 1000°C is 500 MPa and the elongation is 24%.

[0104] Comparative Example 3

[0105] Comparative Example 3 provides a breakdown method of GH4068 alloy, comprising the following steps,

[0106] 1) homogenization treatment: the ingot is subjected to solid solution treatment at 1190°C for 40h, and is cooled to 400°C in the furnace and discharged, to obtain the ingot after homogenization treatment.

[0107] 2) the ingot after homogenization treatment is heated to 1110°C for forging, to obtain the wrought superalloy after breakdown. Among them, the strain of the first heating is 30%, the strain of the second heating is 40%, the strain of the third heating is 50%, the strain of the fourth heating is 60%, the strain of the fifth heating is 80%, and the strain of the sixth heating is 100%, and the final forging temperature of each heating is ≥ 1050°C.

[0108] The microstructure of the wrought superalloy after breakdown of Comparative Example 3 is shown in Figure 8 From Figure 8 it can be seen that there is no micron-sized γ' phase in the wrought superalloy after breakdown of Comparative Example 3, and the matrix grain size is 6.

[0109] In addition, the high-temperature tensile properties of the wrought superalloy after breakdown are shown in Table 1, and the tensile strength at 1000°C is 550 MPa and the elongation is 30%.

[0110] Comparative Example 4

[0111] Comparative Example 4 provides a breakdown method of GH4151 alloy, comprising the following steps,

[0112] 1) homogenization treatment: the ingot is subjected to solid solution treatment at 1200°C for 40h, and is cooled to 400°C in the furnace and discharged, to obtain the ingot after homogenization treatment.

[0113] 2) the ingot after homogenization treatment is heated to 1140°C for forging, to obtain the wrought superalloy after breakdown. Among them, the strain of the first heating is 20%, the strain of the second heating is 30%, the strain of the third heating is 30%, the strain of the fourth heating is 40%, the strain of the fifth heating is 40%, the strain of the sixth heating is 60%, the strain of the seventh heating is 60%, the strain of the eighth heating is 90%, the strain of the ninth heating is 100%, and the strain of the tenth heating is 100%, and the final forging temperature of each heating is ≥ 1080°C.

[0114] The microstructure of the wrought superalloy after breakdown of Comparative Example 4 is shown in Figure 9 From Figure 9It can be seen that there is no micron-sized γ′ phase in the deformed high-temperature alloy of Comparative Example 4 after blanking, and the matrix grain size is level 3.

[0115] In addition, the high temperature tensile properties of the deformed high temperature alloy after blanking in Comparative Example 4 are shown in Table 1. The tensile strength at 1000° C. is 680 MPa, and the elongation is 23%.

[0116] Table 1

[0117]

[0118] Table 1 shows that the plasticizing and opening method for deformed high-temperature alloys proposed in the present invention significantly improves the plasticity of the deformed high-temperature alloy and reduces deformation resistance, thereby facilitating subsequent forming. Furthermore, after forming, the alloy only requires reheat treatment to dissolve the coarse γ′ phase, and the matrix grain size can be adjusted, ensuring that the formed alloy retains excellent mechanical properties.

[0119] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiment based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method of plasticizing breakdown of wrought superalloys, characterized in that, It comprises the following steps: Homogenization treatment: the wrought superalloy ingot is subjected to solution treatment at a temperature of T m +(10-40℃) for 8-20h, and then is subjected to solution treatment at a temperature of T m +(40-70℃) for 16-30h to obtain a homogenized ingot; wherein T m is a complete γ′ phase re-dissolution temperature of the wrought superalloy. Cooling treatment: cooling the homogenized ingot to a first temperature at a set cooling rate to obtain a cooled ingot; wherein the set cooling rate is used to reduce the nucleation rate of γ' phase, so that the γ' phase forming elements are supersaturated in the matrix; wherein the first temperature is T m - (10-60 °C); wherein the set cooling rate is 5-50 °C / h, and by controlling the cooling rate to be the set cooling rate, the nucleation rate of γ' phase is reduced, so that the γ' phase is first nucleated at the grain boundaries to form granular discontinuous micron-sized γ' phase; Coarsening γ' phase treatment: the cast ingot after the cooling treatment is kept at a second temperature for 10-72 h, so that the size of part of the γ' phase in the deformed superalloy is coarsened to micron level, to obtain the cast ingot after the coarsening γ' phase treatment; wherein the second temperature is T m - (10-60 °C); The plasticizing and breaking down process: the cast ingot after the roughening γ' phase treatment is subjected to a plasticizing and breaking down process to obtain a plasticized and broken down wrought superalloy.

2. The method of claim 1, wherein the plasticizing of the wrought superalloy is performed at a temperature of from about 1600°C to about 1750°C. In the step of the roughing forging process: the roughened γ' phase treated ingot is subjected to multiple passes of upsetting and drawing; wherein the first pass strain is 30-50%; the strain increases by no less than 10% with the increase of the pass; the final forging temperature of each pass is ≥T m - (60-100 °C).

3. The method of claim 1 wherein the plasticizing of the wrought superalloy is accomplished by, The γ' phase content in the wrought superalloy is higher than 20wt%; and / or The wrought superalloy is any one of GH4738, GH4065, GH4720Li, GH4068, GH4151.

4. The method of claim 1 wherein, Before the step of the homogenization treatment, it further comprises: An anti-oxidant is sprayed on the surface of the wrought superalloy cast ingot; wherein the anti-oxidant can form a molten glass state on the surface of the wrought superalloy cast ingot after reaching the solid solution temperature, so as to hinder the wrought superalloy cast ingot from contacting with air and avoid high-temperature oxidation.

5. The method of claim 1 wherein, More than 80% of the γ' phase at the grain boundary of the plasticized and broken down wrought superalloy is micron-sized.

6. The method of claim 1 wherein, The content of the γ' phase with a size of ≥1μm in the plasticized and broken down wrought superalloy is 10-40wt%.

7. The method of claim 1 wherein the plasticizing of the wrought superalloy is accomplished by, The grain size of the plasticized and broken down wrought superalloy is higher than 8 levels; and / or The plasticized wrought high temperature alloy has a tensile elongation of ≥ 300% at 1000°C / 10 -2 s -1 MPa at a maximum deformation resistance of ≤ 400 MPa.

8. A plasticized wrought wrought high temperature alloy characterized in that, The plasticized wrought high temperature alloy has a content of γ' phase with a size of ≥1 μm of 10-50 wt%; the grain size of the plasticized wrought high temperature alloy is higher than 8 levels; the plasticized wrought high temperature alloy has a tensile elongation of ≥300% at 1000°C / 10 -2 s -1 MPa under the condition of 1000°C / 10 The plasticized and broken down wrought superalloy is prepared by the plasticizing and breaking down method of the wrought superalloy according to any one of claims 1-7.

9. The plasticized wrought wrought superalloy of claim 8, wherein, More than 80% of the γ' phase at the grain boundary of the plasticized and broken down wrought superalloy is micron-sized.

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