Heat treatment method of GH4169 high-temperature alloy and GH4169 high-temperature alloy

Abstract

The invention provides a heat treatment method of a GH4169 high-temperature alloy and the GH4169 high-temperature alloy, and relates to the technical field of additive manufacturing of high-temperature alloys, the heat treatment method comprises the following steps: carrying out hot isostatic pressing treatment on the GH4169 high-temperature alloy to be treated to reduce pores and Laves phases in the GH4169 high-temperature alloy to be treated, and obtaining the GH4169 high-temperature alloy subjected to hot isostatic pressing treatment; the GH4169 high-temperature alloy subjected to hot isostatic pressing treatment is subjected to homogenization treatment, and the GH4169 high-temperature alloy subjected to homogenization treatment is obtained; and the GH4169 high-temperature alloy subjected to homogenization treatment is sequentially subjected to solution treatment and aging treatment, and the GH4169 high-temperature alloy subjected to heat treatment is obtained. Through hot isostatic pressing treatment, the structure of the alloy is more compact, and meanwhile, the Laves phase in the alloy is reduced; then through homogenization treatment, elements and precipitated phases in the alloy are distributed more uniformly; and the Laves phase is further dissolved through solid solution treatment, and a strengthening phase with more uniform particle size can be conveniently separated out in the aging treatment process, so that the alloy with high toughness and high strength is obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of additive manufacturing of high-temperature alloys, and specifically relates to a heat treatment method for a GH4169 high-temperature alloy and the GH4169 high-temperature alloy. Background Art

[0002] In recent years, laser additive manufacturing technology has played an irreplaceable role in the manufacturing of complex and precision parts due to its characteristics such as free design and near-net shaping. Laser additive manufacturing technology is a process of rapid heating and cooling, and the size of the resulting alloy dendrites / cells and precipitated phases is smaller than that of traditional preparation processes. Selective laser melting (SLM) is one of the most widely studied and applied metal additive manufacturing technologies. This method is considered to be an effective method for manufacturing metal products on an industrial scale. Its products have excellent surface quality, complex shapes and high-precision dimensions. Therefore, this process has developed rapidly in the fields of aerospace, petrochemicals, etc. GH4169 alloy is a precipitation-strengthened nickel-based high-temperature alloy with a similar composition to IN718 alloy. It has good oxidation resistance, high-temperature performance, mechanical properties and welding properties. It is mainly used to manufacture key components such as jet engines, gas turbines, high-speed airframes and turbochargers.

[0003] After heat treatment, the GH4169 superalloy precipitates strengthening phases γ′ phase and γ″ phase, among which the strengthening effect of the latter is much greater than that of the former. However, the GH4169 superalloy is prone to precipitate Laves phase after forming, especially the GH4169 superalloy prepared by SLM. Due to the rapid heating and cooling process in the preparation process, the Laves phase is more likely to precipitate. The Laves phase is hard and brittle, and it is easy to crack when subjected to stress or cracks initiate at the Laves phase / matrix interface. Therefore, the presence of the Laves phase makes the toughness of the GH4169 superalloy lower.

[0004] At present, the heat treatment process of GH4169 high-temperature alloy mostly adopts the method of solid solution + aging. This heat treatment method makes the alloy easy to produce δ phase. The production of δ phase leads to a decrease in the content of γ″ phase (main strengthening phase), resulting in lower strength of GH4169 high-temperature alloy. Summary of the invention

[0005] Therefore, the present invention provides a heat treatment method for a GH4169 high temperature alloy and a GH4169 high temperature alloy, the main purpose of which is to provide a heat treatment method that enables the GH4169 high temperature alloy to have both high toughness and high strength.

[0006] In order to solve the above problems, the present invention provides a heat treatment method for GH4169 high temperature alloy, comprising the following steps:

[0007] Step 1): performing hot isostatic pressing on the GH4169 high temperature alloy to be treated to reduce pores and Laves phase in the GH4169 high temperature alloy to be treated, and obtaining the GH4169 high temperature alloy after hot isostatic pressing;

[0008] Step 2): performing homogenization treatment on the GH4169 high temperature alloy after hot isostatic pressing treatment to avoid segregation of Nb element in the alloy on the grain boundary to form δ phase, and obtaining the GH4169 high temperature alloy after homogenization treatment;

[0009] Step 3): performing solution treatment and aging treatment on the homogenized GH4169 high-temperature alloy in sequence to obtain a heat-treated GH4169 high-temperature alloy.

[0010] Further, the GH4169 high temperature alloy to be treated comprises the following chemical composition, by mass percentage: C: 0.035%-0.045%, Cr: 17.0%-20.0%, Ni: 50.0%-55.0%, Co: 0.49%-0.51%, Mo: 2.8%-3.3%, Al: 0.49%-0.51%, Ti: 0.75%-1.15%, Nb: 4.75%-5.50%, Mn: 0.19%-0.21%, Si: 0.19%-0.21%, Fe balance; and / or

[0011] The GH4169 high-temperature alloy to be processed is an additively manufactured GH4169 alloy.

[0012] Furthermore, the preparation of the GH4169 high temperature alloy to be treated comprises the following steps:

[0013] The steps of preparing the master alloy are as follows: vacuum melting the alloy raw materials and then pouring to obtain the master alloy;

[0014] The step of preparing alloy powder is: atomizing the master alloy into alloy powder;

[0015] Additive manufacturing step: additive manufacturing is performed on the alloy powder using a selective laser melting process to obtain the GH4169 high-temperature alloy to be processed.

[0016] Further, the step of preparing the master alloy comprises: placing the alloy raw material in a vacuum induction furnace for vacuum melting, and performing a pouring treatment after melting to obtain the master alloy; preferably, the vacuum melting temperature is 1450-1630°C; the vacuum melting time is 3-40min; preferably, the pouring temperature is 1420-1490°C; the shell temperature is 600-1200°C; and / or

[0017] In the step of preparing the alloy powder: the master alloy is atomized into alloy powder by a vacuum inert gas atomization method; preferably, the process parameters of the vacuum inert gas atomization are as follows: the powder spraying temperature is 1300-1400°C; the atomization pressure is 7-10MPa; preferably, the particle size of the alloy powder is 18-53μm; and / or

[0018] In the step of additive manufacturing: the process parameters of the selective laser melting process are as follows: scanning rate 600-1500mm / s; laser power is 200-400w; preferably, the scanning rate is 1195-1205mm / s; the laser power is 295-305w; the printing layer thickness is 50μm; the track spacing is 100μm; the interlayer rotation angle is 67°; the substrate preheating temperature is 90-110℃.

[0019] Further, in the step 1):

[0020] The temperature of the hot isostatic pressing treatment is 1070-1090°C; and / or

[0021] The hot isostatic pressing pressure is 110-130 MPa; and / or

[0022] The holding time of the hot isostatic pressing treatment is 1-1.5h.

[0023] Further, in the step 2):

[0024] The temperature of the homogenization treatment is 1070-1090°C; and / or

[0025] The holding time of the homogenization treatment is 1-1.5h.

[0026] Further, in the step 3): a portion of the Laves phase is dissolved by the solid solution treatment; and / or

[0027] The temperature of the solution treatment is 945-965°C; and / or

[0028] The time of the solution treatment is 1-1.5h.

[0029] Further, in the step 3), γ′ phase and γ″ phase are precipitated by the aging treatment; and / or

[0030] The steps of aging treatment include:

[0031] The solution treated GH4169 high temperature alloy is heated to 715-725°C, kept at this temperature for 8-8.5 hours, and then cooled to 615-625°C, kept at this temperature for 8-8.5 hours; preferably, the cooling rate is 8-10°C / h.

[0032] On the other hand, the present invention provides a GH4169 high temperature alloy, wherein the GH4169 high temperature alloy is a heat-treated GH4169 high temperature alloy, and the microstructure of the heat-treated GH4169 high temperature alloy includes a γ′ phase and a γ″ phase.

[0033] Furthermore, the properties of the heat-treated GH4169 high-temperature alloy are as follows: room temperature strength is 1330-1380 MPa; room temperature elongation is 18%-22%; strength at 650°C is 1050-1100 MPa; elongation at 650°C is 10%-15%;

[0034] Preferably, the heat-treated GH4169 high-temperature alloy is obtained by any of the heat treatment methods described above.

[0035] The heat treatment method of a GH4169 high temperature alloy provided by the present invention and the GH4169 high temperature alloy after heat treatment have the following beneficial effects:

[0036] 1. On the one hand, the present invention provides a heat treatment method for a GH4169 high temperature alloy, comprising the following steps: performing hot isostatic pressing on the GH4169 high temperature alloy to be treated to reduce pores and Laves phase in the GH4169 high temperature alloy to be treated, and obtaining the GH4169 high temperature alloy after hot isostatic pressing; performing homogenization on the GH4169 high temperature alloy after hot isostatic pressing to obtain the GH4169 high temperature alloy after homogenization; performing solution treatment and aging treatment on the GH4169 high temperature alloy after homogenization in sequence to obtain the GH4169 high temperature alloy after heat treatment. high-temperature alloy; based on the above method, the present invention reduces the pores in the GH4169 high-temperature alloy to be treated by hot isostatic pressing, makes the structure of the alloy denser, and reduces the Laves phase in the alloy; then, by homogenization treatment, the elements and precipitated phases in the alloy are distributed more evenly, thereby avoiding the segregation of Nb elements on the grain boundaries to form a δ phase; and then by solution treatment, the Laves phase in the alloy is further dissolved in the matrix, thereby ensuring the toughness of the GH4169 high-temperature alloy, and facilitating the precipitation of a strengthening phase with a more uniform particle size during the aging treatment, thereby obtaining an alloy with both high toughness and high strength.

[0037] 2. Furthermore, for the GH4169 high-temperature alloy, after hot isostatic pressing treatment, on the one hand, defects such as pores in the alloy can be reduced to make the alloy structure denser, and on the other hand, the alloy composition can be made more uniform, and then uniform treatment can be carried out to further reduce element segregation and avoid the formation of δ phase, thereby ensuring the strength of the GH4169 high-temperature alloy; at the same time, since the size and orientation of the grains in the transverse and longitudinal sections of the GH4169 high-temperature alloy formed by laser additive manufacturing are not consistent, and the phase difference range is large, the present application increases the temperature of the homogenization treatment to 1070-1090°C, and a structure with a larger proportion of equiaxed crystals can be obtained; in addition, the increase in the temperature of the homogenization treatment is beneficial to reducing the oxide precipitation phase in the alloy and dissolving most of the Laves phase, but if the temperature is too high, the strengthening phase in the alloy will be dissolved, which is not conducive to the mechanical properties of the alloy.

[0038] 3. On the other hand, the present invention provides a heat-treated GH4169 high-temperature alloy, which is prepared by the above-mentioned heat treatment method. The microstructure of the heat-treated GH4169 high-temperature alloy includes a γ′ phase and a γ″ phase; the properties of the heat-treated GH4169 high-temperature alloy are as follows: room temperature strength is 1330-1380MPa; room temperature elongation is 18%-22%; the strength at 650°C is 1050-1100MPa; the elongation at 650°C is 10%-15%. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. The drawings described below are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0040] Figure 1 is a morphology diagram of the alloy powder used in additive manufacturing of the present invention;

[0041] Figure 2 is a metallographic diagram of the GH4169 high-temperature alloy to be processed obtained by the present invention using different additive manufacturing process parameters;

[0042] Figure 3 1 is a microstructure diagram of the GH4169 high temperature alloy before and after heat treatment of the present invention; wherein: (a) is the deposited state, (b) is the comparative example 1, and (c) is the embodiment 1;

[0043] Figure 4 1 is a performance test result diagram of GH4169 high temperature alloy before and after heat treatment of the present invention;

[0044] Figure 5The metallographic microstructure pore diagrams of the GH4169 high-temperature alloy before and after heat treatment of the present invention are shown in FIG. 1 , wherein: (a) is the deposited state, (b) is the comparative example 1, and (c) is the embodiment 1;

[0045] Figure 6 It is a microstructure diagram of the GH4169 high-temperature alloy after heat treatment in comparative example 2 of the present invention. DETAILED DESCRIPTION

[0046] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. The drawings described below are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0047] The present invention provides a heat treatment method for GH4169 high temperature alloy, comprising the following steps:

[0048] Step 1): performing hot isostatic pressing on the GH4169 high temperature alloy to be treated to reduce pores and Laves phase in the GH4169 high temperature alloy to be treated, and then cooling to room temperature to obtain the GH4169 high temperature alloy after hot isostatic pressing;

[0049] Among them, the temperature of hot isostatic pressing treatment is 1070-1090°C; the pressure of hot isostatic pressing treatment is 110-130MPa; the holding time of hot isostatic pressing treatment is 1-1.5h; the GH4169 high-temperature alloy to be treated includes the following chemical compositions by mass percentage: C: 0.035%-0.045%, Cr: 17.0%-20.0%, Ni: 50.0%-55.0%, Co: 0.49%-0.51%, Mo: 2.8%-3.3%, Al: 0.49%-0.51%, Ti: 0.75%-1.15%, Nb: 4.75%-5.50%, Mn: 0.19%-0.21%, Si: 0.19%-0.21%, Fe balance; the GH4169 high-temperature alloy to be treated is the GH4169 alloy manufactured by additive manufacturing; and air cooling is adopted for cooling.

[0050] Step 2): homogenizing the GH4169 high temperature alloy after hot isostatic pressing to avoid segregation of the Nb element in the alloy at the grain boundary to form a δ phase, and cooling to room temperature to obtain the homogenized GH4169 high temperature alloy;

[0051] The temperature of the homogenization treatment is 1070-1090°C; the holding time of the homogenization treatment is 1-1.5h; and air cooling is used for cooling.

[0052] Step 3): The homogenized GH4169 high temperature alloy is subjected to solution treatment and aging treatment in sequence to obtain a heat-treated GH4169 high temperature alloy.

[0053] The temperature of the solution treatment is 945-965°C; the time of the solution treatment is 1-1.5h; after the solution treatment, the alloy is cooled to room temperature to obtain the GH4169 high-temperature alloy after the solution treatment; the cooling is performed by air cooling; the aging treatment steps include: heating the GH4169 high-temperature alloy after the solution treatment to 715-725°C, keeping the temperature for 8-8.5h, and then cooling to 615-625°C, keeping the temperature for 8-8.5h; the cooling is performed by furnace cooling at a cooling rate of 8-10°C / h.

[0054] Based on the above method, the present invention uses hot isostatic pressing to reduce the pores and Laves phase in the GH4169 high-temperature alloy to be treated, making the alloy structure denser and reducing the Laves phase in the alloy; then, through homogenization treatment, the elements and precipitated phases in the alloy are distributed more evenly, thereby avoiding the segregation of Nb elements on the grain boundaries to form δ phases; and then through solid solution treatment, the Laves phase in the alloy is further dissolved in the matrix, thereby ensuring the toughness of the GH4169 high-temperature alloy and facilitating the precipitation of a strengthening phase with a more uniform particle size during the aging treatment. Among them, if the pressure during hot isostatic pressing is too low, the purpose of eliminating internal defects cannot be achieved; if the pressure is too high, the grain morphology in the alloy is completely deformed, and internal defects of compressive stress will also be generated.

[0055] Among them, for GH4169 high temperature alloy, after hot isostatic pressing treatment, on the one hand, defects such as pores in the alloy can be reduced, making the alloy structure denser, and on the other hand, making the alloy composition more uniform, and then uniform treatment can be carried out to further reduce element segregation and avoid the formation of δ phase, thereby ensuring the strength of GH4169 high temperature alloy; at the same time, since the size and orientation of the cross-sectional and longitudinal cross-sectional grains of the GH4169 high temperature alloy formed by laser additive manufacturing are not consistent, and the phase difference range is large, the temperature of the homogenization treatment is increased to 1070-1090℃ in this application, and a large equiaxed crystal ratio can be obtained; in addition, the increase in the temperature of the homogenization treatment is conducive to reducing the oxide precipitation phase in the alloy and dissolving most of the Laves phase, but too high a temperature will dissolve the strengthening phase in the alloy, which is not conducive to the mechanical properties of the alloy. The homogenization treatment realizes the homogenization of the internal structure of the material through atomic diffusion and phase change reaction at high temperature, and can effectively refine the grains. The atoms are rearranged through diffusion, so that the originally coarse grains are gradually refined. Refined grains can significantly improve the mechanical properties and processing properties of materials, such as strength, hardness and plasticity.

[0056] In some embodiments, the preparation of the GH4169 high temperature alloy to be treated comprises the following steps:

[0057] The steps of preparing the master alloy are as follows: vacuum melting the alloy raw materials and then pouring to obtain the master alloy;

[0058] The specific step is: placing the alloy raw material in a vacuum induction furnace for vacuum melting, and then pouring it after melting to obtain the master alloy; wherein the vacuum melting temperature is 1450-1630°C; the vacuum melting time is 3-40min; the pouring temperature is 1420-1490°C; and the shell temperature is 600-1200°C. The vacuum melting ensures that the alloy raw material is fully melted; the setting of the pouring temperature can avoid component segregation, but too high a pouring temperature can easily lead to raw material burning; the shell temperature is the temperature of the mold shell, so before pouring the alloy ingot, the mold shell is preheated to ensure the formation of the alloy ingot (master alloy).

[0059] Preparation of alloy powder steps: atomizing the master alloy into alloy powder by vacuum inert gas atomization method;

[0060] The particle size of the alloy powder is 18-53μm; the process parameters of vacuum inert gas atomization are as follows: the powder spraying temperature is 1300-1400℃; the atomization pressure is 7-10MPa. If the temperature and pressure are not too low, the master alloy cannot be melted, and the quality and weight of the alloy powder cannot meet the requirements; if the temperature is too high, the master alloy directly turns into liquid and the alloy powder cannot be formed.

[0061] Additive manufacturing steps: additive manufacturing of alloy powder using a selective laser melting process to obtain a GH4169 high-temperature alloy to be processed;

[0062] The process parameters of the selective laser melting process are as follows: scanning rate 600-1500mm / s; laser power 200-400w; printing layer thickness 50μm; track spacing 100μm; interlayer rotation angle 67°; substrate preheating temperature 90-110℃. Substrate preheating can avoid temperature gradients during the forming process, thereby reducing the formation of defects such as pores.

[0063] On the other hand, the present invention provides a GH4169 high temperature alloy, which is a heat-treated GH4169 high temperature alloy; the microstructure of the heat-treated GH4169 high temperature alloy includes a γ′ phase and a γ″ phase.

[0064] Furthermore, the properties of the heat-treated GH4169 high-temperature alloy are as follows: room temperature strength is 1330-1380 MPa; room temperature elongation is 18%-22%; strength at 650°C is 1050-1100 MPa; elongation at 650°C is 10%-15%;

[0065] Preferably, the heat-treated GH4169 high-temperature alloy is obtained by any of the above-mentioned heat treatment methods.

[0066] The present invention is further described below with reference to specific embodiments and comparative examples.

[0067] In the embodiments and comparative examples of the present invention, the preparation of the GH4169 high temperature alloy to be treated includes the following steps:

[0068] The steps of preparing the master alloy are as follows: placing the alloy raw material in a vacuum induction furnace for vacuum melting, and performing a pouring treatment after melting to obtain the master alloy; wherein the vacuum melting temperature is 1430°C; the vacuum melting time is 5 minutes; the pouring temperature is 1430°C; and the shell temperature is 950°C;

[0069] Preparation of alloy powder steps: using vacuum inert gas atomization method to atomize the master alloy into alloy powder; wherein, Figure 1 As shown, the particle size of the obtained alloy powder is 18-53 μm; the process parameters of vacuum inert gas atomization are as follows: the powder spraying temperature is 1300-1400°C; the atomization pressure is 7-10 MPa;

[0070] Additive manufacturing steps: The alloy powder is additively manufactured by a selective laser melting process to obtain the GH4169 high-temperature alloy to be processed; wherein, the process parameters of the selective laser melting process are as follows: scanning rate 600-1500mm / s; laser power 200-400w; printing layer thickness 50μm; track spacing 100μm; interlayer rotation angle 67°; substrate preheating temperature 100℃.

[0071] The applicant obtained 12 different groups of GH4169 high-temperature alloys to be processed by changing the scanning rate and laser power using 12 different parameters. The corresponding metallographic structure results are as follows: Figure 2 As shown in the figure, the black part is the defect (pores + unmelted holes). Figure 2 By comparison, the applicant determined that the optimal printing process parameters are: scanning rate of 1200 mm / s, laser power of 300 w; therefore, the specific embodiment and comparative example are the GH4169 high temperature alloy to be processed using these parameters, and the corresponding microstructure is as follows Figure 3 As shown in (a), it can be seen that there is a large amount of Laves phase in the alloy before heat treatment.

[0072] Example 1

[0073] This embodiment provides a heat treatment method for GH4169 high temperature alloy, comprising the following steps:

[0074] Step 1): Perform hot isostatic pressing on the GH4169 superalloy to be treated to reduce the pores and Laves phase in the GH4169 superalloy to be treated, and then air cool to room temperature to obtain the GH4169 superalloy after hot isostatic pressing;

[0075] Among them, the temperature of the hot isostatic pressing is 1080 °C; the pressure of the hot isostatic pressing is 120 MPa; the holding time of the hot isostatic pressing is 1.5 h; by mass percentage, the GH4169 superalloy to be treated includes the following chemical components: C: 0.04%, Cr: 18.5%, Ni: 53%, Co: 0.5%, Mo: 3%, Al: 0.5%, Ti: 1%, Nb: 5%, Mn: 0.2%, Si: 0.2%, and the balance is Fe;

[0076] Step 2): Perform homogenization treatment on the GH4169 superalloy after hot isostatic pressing to avoid the segregation of Nb elements at the grain boundaries to form the δ phase, and air cool to room temperature to obtain the GH4169 superalloy after homogenization treatment;

[0077] Among them, the temperature of the homogenization treatment is 1080 °C; the holding time of the homogenization treatment is 1.5 h;

[0078] Step 3): Perform solution treatment and aging treatment on the GH4169 superalloy after homogenization treatment in sequence to obtain the GH4169 superalloy after heat treatment;

[0079] Among them, the temperature of the solution treatment is 955 °C; the time of the solution treatment is 1 h; after the solution treatment, cool to room temperature to obtain the GH4169 superalloy after solution treatment; among them, the cooling is carried out by air cooling; the steps of the aging treatment include: heating the GH4169 superalloy after solution treatment to 720 °C, holding for 8 h, and then furnace cooling to 620 °C and holding for 8 h.

[0080] The microstructure of the GH4169 superalloy after heat treatment obtained in this example is as Figure 3 (c) shown. It can be seen that the number of Laves phases in the alloy is significantly reduced, and it contains a small amount of δ phase.

[0081] Example 2

[0082] This example provides a heat treatment method for GH4169 superalloy, including the following steps:

[0083] Step 1): Perform hot isostatic pressing on the GH4169 superalloy to be treated to reduce the pores and Laves phase in the GH4169 superalloy to be treated, and then air cool to room temperature to obtain the GH4169 superalloy after hot isostatic pressing;

[0084] The temperature of hot isostatic pressing treatment is 1070°C; the pressure of hot isostatic pressing treatment is 110MPa; the holding time of hot isostatic pressing treatment is 1h; the GH4169 high temperature alloy to be treated includes the following chemical composition by mass percentage: C: 0.04%, Cr: 18.5%, Ni: 53%, Co: 0.5%, Mo: 3%, Al: 0.5%, Ti: 1%, Nb: 5%, Mn: 0.2%, Si: 0.2%, Fe balance;

[0085] Step 2): homogenizing the GH4169 high temperature alloy after hot isostatic pressing to avoid segregation of Nb elements in the alloy on the grain boundaries to form a δ phase and air cooling to room temperature to obtain a homogenized GH4169 high temperature alloy;

[0086] The temperature of the homogenization treatment is 1070°C and the holding time of the homogenization treatment is 1h.

[0087] Step 3): performing solution treatment and aging treatment on the homogenized GH4169 high temperature alloy in sequence to obtain a heat-treated GH4169 high temperature alloy;

[0088] The temperature of the solution treatment is 945°C; the time of the solution treatment is 1 hour; after the solution treatment, the alloy is cooled to room temperature to obtain the GH4169 high-temperature alloy after the solution treatment; the cooling is performed by air cooling; the aging treatment steps include: heating the GH4169 high-temperature alloy after the solution treatment to 715°C, keeping it warm for 8.5 hours, and then furnace cooling it to 615°C and keeping it warm for 8.5 hours.

[0089] The microstructure of the heat-treated GH4169 high-temperature alloy obtained in this embodiment is similar to that of Figure 3 (c) is similar. It can be seen that the amount of Laves phase in the alloy is greatly reduced, and a small amount of δ phase is contained in it.

[0090] Example 3

[0091] This embodiment provides a heat treatment method for GH4169 high temperature alloy, comprising the following steps:

[0092] Step 1): performing hot isostatic pressing on the GH4169 high temperature alloy to be treated to reduce pores and Laves phase in the GH4169 high temperature alloy to be treated, and then air cooling to room temperature to obtain the GH4169 high temperature alloy after hot isostatic pressing;

[0093] The temperature of hot isostatic pressing treatment is 1090°C; the pressure of hot isostatic pressing treatment is 130MPa; the holding time of hot isostatic pressing treatment is 80min; the GH4169 high temperature alloy to be treated includes the following chemical composition by mass percentage: C: 0.04%, Cr: 18.5%, Ni: 53%, Co: 0.5%, Mo: 3%, Al: 0.5%, Ti: 1%, Nb: 5%, Mn: 0.2%, Si: 0.2%, Fe balance;

[0094] Step 2): homogenizing the GH4169 high temperature alloy after hot isostatic pressing to avoid segregation of Nb elements in the alloy on the grain boundaries to form a δ phase and air cooling to room temperature to obtain a homogenized GH4169 high temperature alloy;

[0095] The temperature of the homogenization treatment is 1090°C and the holding time of the homogenization treatment is 1.5h.

[0096] Step 3): performing solution treatment and aging treatment on the homogenized GH4169 high temperature alloy in sequence to obtain a heat-treated GH4169 high temperature alloy;

[0097] The temperature of the solution treatment is 965°C; the time of the solution treatment is 1.5 hours; after the solution treatment, the alloy is cooled to room temperature to obtain the GH4169 high-temperature alloy after the solution treatment; the cooling is performed by air cooling; the aging treatment steps include: heating the GH4169 high-temperature alloy after the solution treatment to 725°C, keeping it warm for 8 hours, and then furnace cooling it to 625°C and keeping it warm for 8 hours.

[0098] The microstructure of the heat-treated GH4169 high-temperature alloy obtained in this embodiment is similar to that of Figure 3 (c) is similar. It can be seen that the amount of Laves phase in the alloy is greatly reduced, and a small amount of δ phase is contained in it.

[0099] Comparative Example 1

[0100] This comparative example provides a heat treatment method for GH4169 high temperature alloy, comprising the following steps:

[0101] Step 1): performing hot isostatic pressing on the GH4169 high temperature alloy to be treated to reduce pores and Laves phase in the GH4169 high temperature alloy to be treated, and then air cooling to room temperature to obtain the GH4169 high temperature alloy after hot isostatic pressing;

[0102] Among them, the temperature of hot isostatic pressing treatment is 1080°C; the pressure of hot isostatic pressing treatment is 120MPa; the holding time of hot isostatic pressing treatment is 1.5h; in terms of mass percentage, the GH4169 high-temperature alloy to be treated includes the following chemical composition: C: 0.04%, Cr: 18.5%, Ni: 53%, Co: 0.5%, Mo: 3%, Al: 0.5%, Ti: 1%, Nb: 5%, Mn: 0.2%, Si: 0.2%, Fe balance;

[0103] Step 2): performing solution treatment and aging treatment on the GH4169 high temperature alloy after hot isostatic pressing treatment in sequence to obtain a heat-treated GH4169 high temperature alloy;

[0104] The temperature of the solution treatment is 955°C; the time of the solution treatment is 1 hour; after the solution treatment, the alloy is cooled to room temperature to obtain the GH4169 high-temperature alloy after the solution treatment; the cooling is performed by air cooling; the aging treatment steps include: heating the GH4169 high-temperature alloy after the solution treatment to 720°C, keeping it warm for 8 hours, and then furnace cooling it to 620°C and keeping it warm for 8 hours.

[0105] The microstructure of the heat-treated GH4169 high-temperature alloy obtained in this comparative example is as follows: Figure 3 As shown in (b), it can be seen that the amount of Laves phase in the alloy is reduced, but a large amount of δ phase is precipitated therein.

[0106] The properties of the GH4169 high temperature alloy before heat treatment and the GH4169 high temperature alloy after heat treatment obtained in Example 1 and Comparative Example 1 were tested. The results are as follows: Figure 4 As shown, it can be seen that the strength of GH4169 high temperature alloy can be improved by heat treatment, but Figure 4 The alloy strength of Example 1 (i.e. Figure 4 The alloy of medium heat treatment 1) has both high strength and high toughness; this is because comparative example 1 was not subjected to homogenization treatment, and the Nb element segregated on the grain boundary to form a δ phase, resulting in poor strength of the alloy.

[0107] Figure 5 The metallographic microstructure pore diagrams of the GH4169 high-temperature alloy before heat treatment and the GH4169 high-temperature alloy after heat treatment obtained in Example 1 and Comparative Example 1 show that the number of pores in the alloy is significantly reduced after heat treatment, and in Example 1, due to the homogenization treatment, the element distribution is more uniform and the number of pores is reduced.

[0108] Comparative Example 2

[0109] This comparative example provides a heat treatment method for GH4169 high temperature alloy, comprising the following steps:

[0110] Step 1): homogenizing the GH4169 high temperature alloy to be treated to avoid the segregation of the Nb element in the alloy on the grain boundary to form the δ phase and air cooling to room temperature to obtain the homogenized GH4169 high temperature alloy;

[0111] The temperature of the homogenization treatment is 1080°C; the holding time of the homogenization treatment is 1.5h; the GH4169 high temperature alloy to be treated includes the following chemical compositions by mass percentage: C: 0.04%, Cr: 18.5%, Ni: 53%, Co: 0.5%, Mo: 3%, Al: 0.5%, Ti: 1%, Nb: 5%, Mn: 0.2%, Si: 0.2%, Fe balance;

[0112] Step 2): performing solution treatment and aging treatment on the homogenized GH4169 high temperature alloy in sequence to obtain a heat-treated GH4169 high temperature alloy;

[0113] The temperature of the solution treatment is 955°C; the time of the solution treatment is 1 hour; after the solution treatment, the alloy is cooled to room temperature to obtain the GH4169 high-temperature alloy after the solution treatment; the cooling is performed by air cooling; the aging treatment steps include: heating the GH4169 high-temperature alloy after the solution treatment to 720°C, keeping it warm for 8 hours, and then furnace cooling it to 620°C and keeping it warm for 8 hours.

[0114] The microstructure of the heat-treated GH4169 high-temperature alloy obtained in this comparative example is as follows: Figure 6 As shown, it can be seen that there are a small amount of cracks in the alloy. This is because the comparative example was not subjected to hot isostatic pressing treatment, and the pore defects of the deposited alloy could not be eliminated, so the mechanical properties of the alloy were poor.

[0115] It is easy for those skilled in the art to understand that, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0116] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present invention. These improvements and variations should also be regarded as the protection scope of the present invention.

Claims

1. A heat treatment method for GH4169 high temperature alloy, characterized in that: The following steps are involved: Step 1): performing hot isostatic pressing on the GH4169 high temperature alloy to be treated to reduce pores and Laves phase in the GH4169 high temperature alloy to be treated, and obtaining the GH4169 high temperature alloy after hot isostatic pressing; Step 2): performing homogenization treatment on the GH4169 high temperature alloy after hot isostatic pressing treatment to avoid segregation of Nb element in the alloy on the grain boundary to form δ phase, and obtaining the GH4169 high temperature alloy after homogenization treatment; Step 3): performing solution treatment and aging treatment on the homogenized GH4169 high-temperature alloy in sequence to obtain a heat-treated GH4169 high-temperature alloy.

2. The heat treatment method of GH4169 high temperature alloy according to claim 1, characterized in that: The GH4169 high temperature alloy to be treated comprises the following chemical composition by mass percentage: C: 0.035%-0.045%, Cr: 17.0%-20.0%, Ni: 50.0%-55.0%, Co: 0.49%-0.51%, Mo: 2.8%-3.3%, Al: 0.49%-0.51%, Ti: 0.75%-1.15%, Nb: 4.75%-5.50%, Mn: 0.19%-0.21%, Si: 0.19%-0.21%, Fe balance; and / or The GH4169 high-temperature alloy to be processed is an additively manufactured GH4169 alloy.

3. The heat treatment method of GH4169 high temperature alloy according to claim 1 or 2, characterized in that: The preparation of the GH4169 high temperature alloy to be treated comprises the following steps: The steps of preparing the master alloy are as follows: vacuum melting the alloy raw materials and then pouring to obtain the master alloy; The step of preparing alloy powder is: atomizing the master alloy into alloy powder; Additive manufacturing step: additive manufacturing is performed on the alloy powder using a selective laser melting process to obtain the GH4169 high-temperature alloy to be processed.

4. The heat treatment method of GH4169 high temperature alloy according to claim 3, characterized in that: The step of preparing the master alloy comprises: placing the alloy raw material in a vacuum induction furnace for vacuum melting, and performing a pouring treatment after melting to obtain the master alloy; preferably, the vacuum melting temperature is 1450-1630°C; the vacuum melting time is 3-40 minutes; preferably, the pouring temperature is 1420-1490°C; the shell temperature is 600-1200°C; and / or In the step of preparing the alloy powder: the master alloy is atomized into alloy powder by a vacuum inert gas atomization method; preferably, the process parameters of the vacuum inert gas atomization are as follows: the powder spraying temperature is 1300-1400°C; the atomization pressure is 7-10MPa; preferably, the particle size of the alloy powder is 18-53μm; and / or In the step of additive manufacturing: the process parameters of the selective laser melting process are as follows: scanning rate 600-1500mm / s; laser power is 200-400w; preferably, the scanning rate is 1195-1205mm / s; the laser power is 295-305w; the printing layer thickness is 50μm; the track spacing is 100μm; the interlayer rotation angle is 67°; the substrate preheating temperature is 90-110℃.

5. The heat treatment method of GH4169 high temperature alloy according to claim 1, characterized in that: In the step 1): The temperature of the hot isostatic pressing treatment is 1070-1090°C; and / or The hot isostatic pressing treatment has a pressure of 110-130 MPa; and / or The holding time of the hot isostatic pressing treatment is 1-1.5h.

6. The heat treatment method of GH4169 high temperature alloy according to claim 1, characterized in that: In the step 2): The temperature of the homogenization treatment is 1070-1090°C; and / or The holding time of the homogenization treatment is 1-1.5h.

7. The heat treatment method of GH4169 high temperature alloy according to claim 1, characterized in that: In the step 3): dissolving part of the Laves phase by the solid solution treatment; and / or The temperature of the solution treatment is 945-965°C; and / or The time of the solution treatment is 1-1.5h.

8. The heat treatment method of GH4169 high temperature alloy according to claim 1, characterized in that: In the step 3): precipitating γ′ phase and γ″ phase through the aging treatment; and / or The steps of aging treatment include: The solution treated GH4169 high temperature alloy is heated to 715-725°C, kept at this temperature for 8-8.5 hours, and then cooled to 615-625°C, kept at this temperature for 8-8.5 hours; preferably, the cooling rate is 8-10°C / h.

9. A GH4169 high temperature alloy, characterized in that: The GH4169 high temperature alloy is a heat-treated GH4169 high temperature alloy, and the microstructure of the heat-treated GH4169 high temperature alloy includes a γ′ phase and a γ″ phase.

10. The GH4169 high temperature alloy according to claim 9, characterized in that: The properties of the heat-treated GH4169 high-temperature alloy are as follows: room temperature strength is 1330-1380 MPa; room temperature elongation is 18%-22%; strength at 650°C is 1050-1100 MPa; elongation at 650°C is 10%-15%; Preferably, the heat-treated GH4169 high-temperature alloy is obtained by the heat treatment method according to any one of claims 1 to 8.

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