Heat treatment method for additive manufacturing of Re-containing nickel-based superalloy

Abstract

The invention relates to a heat treatment method for additive manufacturing of Re-containing nickel-based superalloy, and relates to the technical field of additive manufacturing of superalloy. According to the main technical scheme, the heat treatment method comprises the following steps that hot isostatic pressing treatment is conducted on the deposited additive manufacturing Re-containing nickel-based high-temperature alloy, so that the defects of the deposited additive manufacturing Re-containing nickel-based high-temperature alloy are closed, and the alloy subjected to hot isostatic pressing treatment is obtained; stress relief annealing treatment is conducted on the alloy subjected to hot isostatic pressing treatment, and the alloy subjected to stress relief annealing treatment is obtained; carrying out solution treatment on the alloy subjected to the stress relief annealing treatment to obtain the alloy subjected to the solution treatment; wherein the temperature of the solution treatment ranges from 1280 DEG C to 1330 DEG C, and the time of the solution treatment ranges from 0.5 h to 2 h; and aging treatment is conducted on the alloy obtained after solution treatment, and the heat-treatment-state additive manufacturing Re-containing nickel-based high-temperature alloy is obtained. The method is mainly used for improving the strength and plasticity of the additive manufacturing Re-containing nickel-based high-temperature alloy.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of additive manufacturing of high-temperature alloys, and particularly relates to a heat treatment method for additive manufacturing of Re-containing nickel-based high-temperature alloys. BACKGROUND

[0002] Nickel-based high-temperature alloys have excellent room-temperature and high-temperature strength, good oxidation resistance, creep resistance and other properties, and are suitable for the preparation of hot-end components in the fields of aerospace and the like. Traditional preparation methods (such as casting and forging) generally have the characteristics of complicated steps, long preparation period and the like, and have certain limitations for the preparation of complex structural parts.

[0003] Additive manufacturing technology can realize near-net forming of complex high-temperature alloy parts through flexible design by computer and layer-by-layer rapid prototyping. Of course, heat treatment of the additive manufactured high-temperature alloy is also essential, and the internal defects, residual stress state and precipitate phase morphology of the alloy need to be controlled through heat treatment.

[0004] In the field of heat treatment of additive manufactured nickel-based high-temperature alloys, with the increasing types of alloying elements, the heat treatment process is becoming more and more complex. Among them, the addition of rhenium Re element can significantly improve the temperature resistance of the alloy and reduce the coarsening rate of the γ' strengthening phase, thereby improving the high-temperature mechanical properties of the alloy. However, due to the low diffusion coefficient of Re element, it is difficult to homogenize and easy to segregate to form harmful phases, so that the strength and plasticity of the additive manufactured high-temperature alloy are difficult to be synergistically improved.

[0005] Therefore, there is an urgent need for a heat treatment process for additive manufacturing of Re-containing nickel-based high-temperature alloys to solve the technical problem that the strength and plasticity of the additive manufactured high-temperature alloy are difficult to be synergistically improved. SUMMARY

[0006] Therefore, the present application provides a heat treatment method for additive manufacturing of Re-containing nickel-based high-temperature alloys, which mainly aims to improve the strength and plasticity of the additive manufactured Re-containing nickel-based high-temperature alloy.

[0007] To achieve the above-mentioned purpose, the present application mainly provides the following technical solutions: On the one hand, the present application provides a heat treatment method for additive manufacturing of Re-containing nickel-based high-temperature alloys, which includes the following steps: Hot isostatic pressing treatment: the additive manufacturing Re-containing nickel-based superalloy in a deposited state is subjected to hot isostatic pressing treatment for eliminating crack and hole defects of the additive manufacturing Re-containing nickel-based superalloy in a deposited state, to obtain an alloy after hot isostatic pressing treatment; wherein the additive manufacturing Re-containing nickel-based superalloy in a deposited state comprises the following chemical components in percentage by weight: Cr: 2-8wt%, C: 0.01-0.1wt%, Mo: 2-5wt%, W: 5-8wt%, Co: 7-11wt%, Al: 3-8wt%, Ti: 1-3wt%, Ta: 4-8wt%, B: 0.03-0.1wt%, Re: 0-4wt%, and the balance of Ni; Stress relief annealing treatment: the alloy after hot isostatic pressing treatment is subjected to stress relief annealing treatment, to obtain an alloy after stress relief annealing treatment; Solution treatment: the alloy after stress relief annealing treatment is subjected to solution treatment, to obtain an alloy after solution treatment; wherein the solution treatment is at a temperature of 1280-1330℃ for 0.5-2h; Aging treatment: the alloy after solution treatment is subjected to aging treatment, to obtain an additive manufacturing Re-containing nickel-based superalloy in a heat-treated state.

[0008] Preferably, the step of preparing the additive manufacturing Re-containing nickel-based superalloy in a deposited state comprises: using a Re-containing nickel-based superalloy powder as raw material, and printing a Re-containing nickel-based superalloy sample in a deposited state by selective laser melting technology. Preferably, the additive manufacturing Re-containing nickel-based superalloy in a deposited state is in a molten pool morphology, wherein the width of the molten pool is about 70-80μm.

[0009] Preferably, the particle size of the Re-containing nickel-based superalloy powder is 15-53μm.

[0010] Preferably, the parameters of the selective laser melting printing are set as follows: laser power is 180-280W; scanning speed is 800-1100mm / s; printing layer thickness is 40-50μm; track spacing is 70-90μm; and layer-to-layer angle is 90°.

[0011] Preferably, in the step of hot isostatic pressing treatment: the temperature of the hot isostatic pressing treatment is 1180-1210℃, the pressure of the hot isostatic pressing treatment is 170-180MPa, and the time of the hot isostatic pressing treatment is 2-4h.

[0012] Preferably, in the step of stress relief annealing treatment: the temperature of the stress relief annealing treatment is 600-700℃; and the time of the stress relief annealing treatment is 4-10h.

[0013] Preferably, in the step of the solution treatment, after the high-temperature heat treatment furnace is heated to the solution treatment temperature, the alloy after the stress relief annealing treatment is placed in the high-temperature heat treatment furnace for solution heat treatment, and after cooling, the alloy after the solution treatment is obtained; preferably, the cooling mode is selected as the air cooling mode.

[0014] Preferably, the aging treatment comprises: The first aging treatment is performed on the alloy after the solution treatment, and after cooling, the alloy after the first aging treatment is obtained; wherein the temperature of the first aging treatment is 1100-1120℃, and the time of the first aging treatment is 2-4h; preferably, the cooling mode is selected as the air cooling mode. The second aging treatment is performed on the alloy after the first aging treatment, and after cooling, the additive manufacturing Re-containing nickel-based superalloy in the heat-treated state is obtained; wherein the temperature of the second aging treatment is 850-870℃, and the time of the second aging treatment is 20-24h.

[0015] In another aspect, the embodiment of the present application provides an additive manufacturing Re-containing nickel-based superalloy in a heat-treated state, wherein in the additive manufacturing Re-containing nickel-based superalloy in the heat-treated state: the grain boundaries and the grains are both dispersedly distributed with granular carbides; wherein the size of the granular carbides at the grain boundaries is 0.2-2.2μm, and the size of the carbides in the grains is about 0.1-0.4μm; cubic γ′ phases are uniformly precipitated in the grains, and the size of the cubic γ′ phases is 350-450nm; and the Re element is solid-solved in the γ matrix to play a solid-solution strengthening role.

[0016] Preferably, under the condition of room temperature, the tensile strength of the additive manufacturing Re-containing nickel-based superalloy in the heat-treated state is 1300-1350MPa, the yield strength is 950-1000MPa, and the elongation is 15%-20%; and / or under the condition of the tensile test at 900℃, the tensile strength of the additive manufacturing Re-containing nickel-based superalloy in the heat-treated state is 850-870MPa, the yield strength is 750-800MPa, and the elongation is 5%-10%.

[0017] Preferably, the additive manufacturing Re-containing nickel-based superalloy in the heat-treated state is obtained by adopting the heat treatment method of the additive manufacturing Re-containing nickel-based superalloy in the heat-treated state according to any one of the above-mentioned heat treatment methods.

[0018] Compared with the prior art, the additive manufacturing Re-containing nickel-based superalloy and the preparation method thereof have at least the following beneficial effects: The embodiment provides a heat treatment method of additive manufacturing Re-containing nickel-based superalloy, which comprises the following steps: performing hot isostatic pressing treatment on the additive manufacturing Re-containing nickel-based superalloy in a deposited state, so that defects of the additive manufacturing Re-containing nickel-based superalloy in the deposited state are closed, and an alloy after the hot isostatic pressing treatment is obtained; wherein the additive manufacturing Re-containing nickel-based superalloy in the deposited state comprises the following chemical components in percentage by weight: Cr: 2-8 wt%, C: 0.01-0.1 wt%, Mo: 2-5 wt%, W: 5-8 wt%, Co: 7-11 wt%, Al: 3-8 wt%, Ti: 1-3 wt%, Ta: 4-8 wt%, B: 0.03-0.1 wt%, Re: 0-4 wt%, and the balance is Ni; performing stress relief annealing treatment on the alloy after the hot isostatic pressing treatment, so that an alloy after the stress relief annealing treatment is obtained; performing solid solution treatment on the alloy after the stress relief annealing treatment, so that an alloy after the solid solution treatment is obtained; wherein the temperature of the solid solution treatment is 1280-1330 DEG C, and the time is 0.5-2 h; and performing aging treatment on the alloy after the solid solution treatment, so that the additive manufacturing Re-containing nickel-based superalloy in a heat treated state is obtained. In this regard, for the additive manufacturing Re-containing nickel-based superalloy with the above chemical components, the embodiment of the application first improves the density of the additive manufacturing Re-containing nickel-based superalloy through the hot isostatic pressing, then eliminates new stress introduced after the hot isostatic pressing through the stress relief annealing, then improves the element uniformity of the alloy through the designed new high-temperature short-time solid solution treatment process, and finally regulates the volume fraction and morphology of the strengthening phase through the double-stage aging, so that the strength and plasticity of the additive manufacturing Re-containing nickel-based superalloy are improved, and thus an innovative solution is provided for the heat treatment of the additive manufacturing Re-containing nickel-based superalloy.

[0019] The above description is only a summary of the technical scheme of the application, in order to more clearly understand the technical means of the application and can be implemented according to the content of the specification, the following is a preferred embodiment of the application and the accompanying drawings are described as follows. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a morphology diagram of the high-temperature alloy powder in embodiment 1; Figure 2 is a metallographic structure diagram of the additive manufacturing Re-containing nickel-based superalloy in a deposited state, wherein, (a) is a pool morphology of a cross section of the additive manufacturing Re-containing nickel-based superalloy in the deposited state, and (b) is a pool and grain morphology of a longitudinal section of the additive manufacturing Re-containing nickel-based superalloy in the deposited state; Figure 3 is a microstructure of the additive manufacturing Re-containing nickel-based superalloy in a hot isostatic pressing state; Figure 4is a microstructure of a heat-treated state of an additive manufacturing Re-containing nickel-based superalloy, wherein (a) is a grain boundary and intragranular precipitate phase morphology of the heat-treated state of the additive manufacturing Re-containing nickel-based superalloy of Example 1, (b) is a grain boundary and intragranular precipitate phase morphology of the heat-treated state of the additive manufacturing Re-containing nickel-based superalloy of Example 2, and (c) is a grain boundary and intragranular precipitate phase morphology of the heat-treated state of the additive manufacturing Re-containing nickel-based superalloy of Example 3; Figure 5 is a grain boundary and intragranular precipitate phase morphology of a heat-treated state of an additive manufacturing Re-containing nickel-based superalloy prepared in Comparative Example 1; Figure 6 is a grain boundary and intragranular precipitate phase morphology of a heat-treated state of an additive manufacturing Re-containing nickel-based superalloy prepared in Comparative Example 2; Figure 7 is a grain boundary and intragranular precipitate phase morphology of a heat-treated state of an additive manufacturing Re-containing nickel-based superalloy prepared in Comparative Example 3; Figure 8 is a grain boundary and intragranular precipitate phase morphology of a heat-treated state of an additive manufacturing alloy prepared in Comparative Example 4, wherein (a) is a grain boundary precipitate phase morphology, and (b) is an intragranular precipitate phase morphology. DETAILED DESCRIPTION

[0021] To further illustrate the technical means and effects taken by the present application to achieve the intended purpose, the specific embodiments, structures, features and effects according to the present application are described in detail below in conjunction with the drawings and preferred embodiments. In the following description, different "an embodiment" or "embodiments" do not necessarily refer to the same embodiment. In addition, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0022] For precipitation-strengthened superalloys, the currently used heat treatment process is solution and aging, and for additive manufacturing superalloys, stress relief annealing and hot isostatic pressing steps are also necessary. The present application provides a heat treatment method for additive manufacturing Re-containing nickel-based superalloys, mainly for additive manufacturing nickel-based superalloys containing high refractory elements (rhenium element), which obtains alloys with high strength and high toughness at room temperature and high temperature. Specifically, for the additive manufacturing Re-containing nickel-based superalloy described in the present application, the present application provides a "super-high-temperature short-time solution" heat treatment process, which greatly improves the strength and plasticity compared with the as-deposited alloy under room temperature and high temperature tensile test conditions, solving the technical problem of difficult simultaneous improvement of strength and plasticity of additive manufacturing superalloys. The scheme of the present application is mainly as follows: The embodiment of the present application provides a heat treatment method for additive manufacturing Re-containing nickel-based superalloys, which comprises the following steps: hot isostatic pressing treatment: the as-deposited additive manufacturing Re-containing nickel-based superalloy is subjected to hot isostatic pressing treatment to close the defects of the as-deposited additive manufacturing Re-containing nickel-based superalloy, so as to obtain the alloy after hot isostatic pressing treatment (after the hot isostatic pressing treatment, the alloy is cooled to room temperature in the furnace).

[0023] The as-deposited additive manufacturing Re-containing nickel-based superalloy comprises the following chemical components in terms of weight percentage: Cr: 2-8 wt%, C: 0.01-0.1 wt%, Mo: 2-5 wt%, W: 5-8 wt%, Co: 7-11 wt%, Al: 3-8 wt%, Ti: 1-3 wt%, Ta: 4-8 wt%, B: 0.03-0.1 wt%, Re: 0-4 wt%, and the balance being Ni.

[0024] The preparation step of the as-deposited additive manufacturing Re-containing nickel-based superalloy comprises: taking a Re-containing nickel-based superalloy powder as a raw material, and printing an as-deposited Re-containing nickel-based superalloy sample by using a selective laser melting technology. Preferably, the particle size of the Re-containing nickel-based superalloy powder is 15-53 μm (the Re-containing nickel-based superalloy powder is prepared by using a gas atomization method). The parameters of the selective laser melting printing are set as follows: the laser power is 180-280 W; the scanning speed is 800-1100 mm / s; the printing layer thickness is 40-50 μm; the track spacing is 70-90 μm; and the layer-to-layer angle is 90°.

[0025] stress relief annealing treatment: the alloy after the hot isostatic pressing treatment is subjected to stress relief annealing treatment to eliminate new stresses introduced in the hot isostatic pressing process, so as to obtain the alloy after the stress relief annealing treatment.

[0026] The temperature of the stress relief annealing treatment is 600-700 °C, and the time of the stress relief annealing treatment is 4-10 h.

[0027] solution treatment: the alloy after the stress relief annealing treatment is subjected to solution treatment, so as to obtain the alloy after the solution treatment; wherein the temperature of the solution treatment is 1280-1330 °C, and the time of the solution treatment is 0.5-2 h.

[0028] After the high-temperature heat treatment furnace is heated to the solution treatment temperature, the alloy after the stress relief annealing treatment is placed in the high-temperature heat treatment furnace for solution heat treatment. After cooling, the alloy after the solution treatment is obtained. Preferably, the cooling mode is selected as an air cooling mode.

[0029] aging treatment: the alloy after the solution treatment is subjected to aging treatment, so as to obtain the additive manufacturing Re-containing nickel-based superalloy in a heat-treated state. The aging treatment comprises: The primary aging treatment is performed on the alloy after the solid solution treatment, and after cooling, an alloy after the primary aging treatment is obtained; wherein the temperature of the primary aging treatment is 1100-1120℃, and the time of the primary aging treatment is 2-4h; preferably, the cooling mode is selected as an air cooling mode; The secondary aging treatment is performed on the alloy after the primary aging treatment, and after cooling, a hot-treated additive manufacturing Re-containing nickel-based high-temperature alloy is obtained; wherein the temperature of the secondary aging treatment is 850-870℃, and the time of the secondary aging treatment is 20-24h.

[0030] Here, the above scheme of the present application is described as follows: 1) In the preparation of the additive manufacturing Re-containing nickel-based high-temperature alloy in the deposition state in the embodiment of the present application: the alloy powder is prepared by the gas atomization method; the printing process exploration of the alloy is performed by the selective laser melting technology, and the additive manufacturing high-temperature alloy with good formability and few defects is prepared.

[0031] 2) The heat treatment method of the present application comprises: hot isostatic pressing treatment on the additive manufacturing Re-containing nickel-based high-temperature alloy in the deposition state to obtain an alloy after the hot isostatic pressing treatment; stress relief annealing to eliminate the internal stress of the alloy; solid solution treatment on the alloy after the stress relief annealing treatment to obtain an alloy after the solid solution treatment; and double-stage aging treatment on the alloy after the solid solution treatment to obtain a hot-treated alloy. Based on the above method, the present application reduces the defects in the alloy by the hot isostatic pressing treatment, so that the structure of the alloy is more compact and stable; the new stress introduced in the hot isostatic pressing process is eliminated by the stress relief annealing; the granular carbide dispersedly distributed in the alloy is precipitated by the solid solution treatment; and the irregularly distributed γ' phase is regulated to be cubic by the aging treatment, so that the alloy has high strength and high toughness.

[0032] 3) The microstructure of the hot-treated additive manufacturing Re-containing nickel-based high-temperature alloy obtained by the heat treatment method of the present application comprises γ' strengthening phase and dispersedly distributed granular carbide. The performance of the hot-treated additive manufacturing Re-containing nickel-based high-temperature alloy is as follows: the tensile strength of the hot-treated additive manufacturing Re-containing nickel-based high-temperature alloy is 1300-1350MPa, the yield strength is 950-1000MPa, and the elongation is 15%-20%; and / or under the tensile test condition at 900℃, the tensile strength of the hot-treated additive manufacturing Re-containing nickel-based high-temperature alloy is 850-870MPa, the yield strength is 750-800MPa, and the elongation is 5%-10%.

[0033] The present application is further described below through examples: Example 1 The embodiment provides a heat treatment method of additive manufacturing Re-containing nickel-based superalloy, wherein a preparation step of the additive manufacturing Re-containing nickel-based superalloy in a deposited state is as follows: a vacuum inert gas atomization method is used to prepare a superalloy powder, wherein process parameters are as follows: a powder spraying temperature is 1400 DEG C, and an atomization pressure is 10 MPa. As shown in the figure, the superalloy powder has a morphology. As shown in the figure, the powder has a particle size of 15-53 μm. The superalloy powder is formed into the additive manufacturing Re-containing nickel-based superalloy in the deposited state by using a selective laser melting additive manufacturing technology, wherein process parameters of the selective laser melting technology are as follows: a laser power is 200 W; a scanning speed is 800 mm / s; a printing layer thickness is 40 μm; a track spacing is 70 μm; and a layer interconversion angle is 90 DEG. Figure 1

[0034] As shown in the figure, the additive manufacturing Re-containing nickel-based superalloy in the deposited state has a metallographic structure, wherein, Figure 2 Figure 2 As shown in the figure, the additive manufacturing Re-containing nickel-based superalloy in the deposited state has a cross-section molten pool morphology, Figure 2 As shown in the figure, the additive manufacturing Re-containing nickel-based superalloy in the deposited state has a longitudinal cross-section molten pool morphology, a molten pool width is about 70-80 μm, and an arrow direction is a crack defect in the alloy.

[0035] As shown in the figure, the additive manufacturing Re-containing nickel-based superalloy in the deposited state has a chemical composition in percentage by weight as follows: Cr: 8 wt%, C: 0.05 wt%, Mo: 2.5 wt%, W: 6 wt%, Co: 8 wt%, Al: 5.5 wt%, Ti: 3 wt%, Ta: 6 wt%, B: 0.04 wt%, Re: 4 wt%, and the balance is Ni.

[0036] As shown in the figure, the additive manufacturing Re-containing nickel-based superalloy in the deposited state has a chemical composition in percentage by weight as follows: Cr: 8 wt%, C: 0.05 wt%, Mo: 2.5 wt%, W: 6 wt%, Co: 8 wt%, Al: 5.5 wt%, Ti: 3 wt%, Ta: 6 wt%, B: 0.04 wt%, Re: 4 wt%, and the balance is Ni. As shown in the figure, the additive manufacturing Re-containing nickel-based superalloy in the deposited state has a chemical composition in percentage by weight as follows: Cr: 8 wt%, C: 0.05 wt%, Mo: 2.5 wt%, W: 6 wt%, Co: 8 wt%, Al: 5.5 wt%, Ti: 3 wt%, Ta: 6 wt%, B: 0.04 wt%, Re: 4 wt%, and the balance is Ni. Figure 3 As shown in the figure, the additive manufacturing Re-containing nickel-based superalloy in the deposited state has a chemical composition in percentage by weight as follows: Cr: 8 wt%, C: 0.05 wt%, Mo: 2.5 wt%, W: 6 wt%, Co: 8 wt%, Al: 5.5 wt%, Ti: 3 wt%, Ta: 6 wt%, B: 0.04 wt%, Re: 4 wt%, and the balance is Ni.

[0037] As shown in the figure, the additive manufacturing Re-containing nickel-based superalloy in the deposited state has a chemical composition in percentage by weight as follows: Cr: 8 wt%, C: 0.05 wt%, Mo: 2.5 wt%, W: 6 wt%, Co: 8 wt%, Al: 5.5 wt%, Ti: 3 wt%, Ta: 6 wt%, B: 0.04 wt%, Re: 4 wt%, and the balance is Ni.

[0038] ​​Solution treatment: the high-temperature heat treatment furnace is heated, and after reaching the solution treatment temperature, the alloy after stress relief annealing treatment is placed in the high-temperature heat treatment furnace for solution heat treatment (wherein the solution treatment temperature is 1280℃, and the time is 2h), and then air cooling, the alloy after solution treatment is obtained.

[0039] Aging treatment: the alloy after solution treatment is subjected to primary aging treatment, and after air cooling, the alloy after primary aging treatment is obtained; wherein the primary aging treatment temperature is 1120℃, and the primary aging treatment time is 4h. The alloy after primary aging treatment is subjected to secondary aging treatment, and after air cooling, the additive manufacturing Re-containing nickel-based superalloy in a heat-treated state is obtained; wherein the secondary aging treatment temperature is 870℃, and the secondary aging treatment time is 24h.

[0040] The microstructure of the additive manufacturing Re-containing nickel-based superalloy obtained in the embodiment is shown in (a) of FIG. 1. Figure 4 As can be seen from (a) of FIG. 1, on the basis of hot isostatic pressing, stress relief annealing, solution and aging, the high-temperature solution treatment of the embodiment causes the grains to grow rapidly, the melt pool structure in the alloy structure disappears, a large amount of granular carbide is precipitated at the grain boundaries and in the grains, the size of the granular carbide at the grain boundaries is about 0.7-2.2μm, and the size of the granular carbide in the grains is about 0.1-0.4μm; a large amount of cubic γ' phase is uniformly precipitated in the grains, and the size is about 350-450nm.

[0041] Embodiment 2 The embodiment provides a heat treatment method of an additive manufacturing Re-containing nickel-based superalloy, which is mainly different from that of embodiment 1 in that: Solution treatment: the high-temperature heat treatment furnace is heated, and after reaching the solution treatment temperature, the alloy after stress relief annealing treatment is placed in the high-temperature heat treatment furnace for solution heat treatment (wherein the solution treatment temperature is 1300℃, and the time is 1h), and then air cooling, the alloy after solution treatment is obtained.

[0042] The other steps and parameters are consistent with those of embodiment 1.

[0043] The microstructure of the additive manufacturing Re-containing nickel-based superalloy obtained in the embodiment is shown in (b) of FIG. 1. Figure 4 As can be seen from (b) of FIG. 1, due to the high-temperature short-time solution treatment in the embodiment, the grains grow rapidly, the melt pool structure in the alloy structure disappears, a large amount of granular carbide is precipitated at the grain boundaries and in the grains, the size of the granular carbide at the grain boundaries is about 0.2-1.5μm, and the size of the granular carbide in the grains is about 0.1-0.4μm; a large amount of cubic γ' phase is uniformly precipitated in the grains, and the size is about 350-450nm.

[0044] Embodiment 3 The embodiment provides a heat treatment method of additive manufacturing Re-containing nickel-based superalloy, and the main difference from the embodiment 1 is as follows: Solution treatment: the high-temperature heat treatment furnace is heated, after reaching the solution treatment temperature, the stress relief annealed alloy is placed in the high-temperature heat treatment furnace for solution heat treatment (wherein the solution treatment temperature is 1330 DEG C, and the time is 0.5 h), and then, after air cooling, the solution treated alloy is obtained.

[0045] Other steps and parameters are consistent with the embodiment.

[0046] The microstructure of the additive manufacturing Re-containing nickel-based superalloy obtained in the embodiment is as shown in the (c) graph of FIG. 1. Figure 4 As can be seen from the (c) graph of FIG. 1, due to the high-temperature short-time solution treatment in the embodiment, the grains grow rapidly, the molten pool structure in the alloy organization disappears, a large amount of granular carbide is precipitated at the grain boundary and in the grain, the size of the granular carbide at the grain boundary is about 0.4-1.4 μm, the size of the granular carbide in the grain is about 0.1-0.4 μm, and a large amount of cubic γ' phase is uniformly precipitated in the grain, and the size is about 400-450 nm.

[0047] Comparative example 1 The comparative example provides a heat treatment method of additive manufacturing Re-containing nickel-based superalloy, wherein the preparation steps of the additive manufacturing Re-containing nickel-based superalloy in the deposited state are shown in the embodiment 1.

[0048] Solution treatment: the high-temperature heat treatment furnace is heated, after reaching the solution treatment temperature, the stress relief annealed alloy is placed in the high-temperature heat treatment furnace for solution heat treatment (wherein the solution treatment temperature is 1330 DEG C, and the time is 0.5 h), and then, after air cooling, the solution treated alloy is obtained.

[0049] Aging treatment: the solution treated alloy is subjected to primary aging treatment, and after air cooling, the primary aging treated alloy is obtained; wherein the primary aging treatment temperature is 1120 DEG C, and the primary aging treatment time is 4 h. The primary aging treated alloy is subjected to secondary aging treatment, and after air cooling, the heat treated additive manufacturing Re-containing nickel-based superalloy is obtained; wherein the secondary aging treatment temperature is 870 DEG C, and the secondary aging treatment time is 24 h.

[0050] Figure 5 The grain boundary morphology of the heat treated additive manufacturing Re-containing nickel-based superalloy prepared in the comparative example 1 is shown in the (c) graph of FIG. 1. Figure 5 As can be seen from the (c) graph of FIG. 1, in the case that the hot isostatic pressing is not performed, the holes still exist. In addition, the irregular carbide is precipitated on the grain boundary, and the volume fraction is large, which is not conducive to the performance of the alloy.

[0051] Comparative example 2 Comparative Example 2 provides a heat treatment method of the additive manufacturing Re-containing nickel-based superalloy, the main difference with Example 1 is that: Solution treatment: the high-temperature heat treatment furnace is heated, after reaching the solution treatment temperature, the stress relief annealed alloy is put into the high-temperature heat treatment furnace for solution heat treatment (wherein the solution treatment temperature is 1200℃, and the time is 1h), after air cooling, the solution treated alloy is obtained.

[0052] Other steps and parameters are consistent with Example 1.

[0053] Figure 6 The grain boundary and intracrystalline precipitated phase morphology of the heat treated additive manufacturing Re-containing nickel-based superalloy prepared in Comparative Example 2 is shown in Figure 6, from which it can be seen that: Figure 6 It can be seen that: due to the low solution temperature, the effect of γ' strengthening phase resolubilization is affected, although γ' strengthening phase precipitates in the intracrystalline, it is not the best cubic morphology.

[0054] Comparative Example 3 Comparative Example 3 provides a heat treatment method of the additive manufacturing Re-containing nickel-based superalloy, the main difference with Example 2 is that: Aging treatment: the solution treated alloy is subjected to primary aging treatment, and after air cooling, the primary aging treated alloy is obtained; wherein the primary aging treatment temperature is 1130℃, and the primary aging treatment time is 4h. The primary aging treated alloy is subjected to secondary aging treatment, and after air cooling, the heat treated additive manufacturing Re-containing nickel-based superalloy is obtained; wherein the secondary aging treatment temperature is 870℃, and the secondary aging treatment time is 24h.

[0055] Other steps and parameters are consistent with Example 1.

[0056] Figure 7 The grain boundary and intracrystalline precipitated phase morphology of the heat treated additive manufacturing Re-containing nickel-based superalloy prepared in Comparative Example 3 is shown in Figure 7, from which it can be seen that: Figure 7 It can be seen that: after increasing the aging temperature, the matrix channel becomes wider, and a large amount of secondary γ' phase is precipitated, resulting in a decrease in the volume fraction of γ' phase.

[0057] Comparative Example 4 This comparative example provides a heat treatment method of the additive manufacturing nickel-based superalloy, which comprises the following steps: GH4099 alloy powder is prepared into a plurality of mechanical property detection samples by using a selective laser melting process. Among them, the forming process parameters of the selective laser melting are layer thickness 40μm, laser power 300W, scanning speed 1200mm / s, and scanning spacing 0.075mm.

[0058] The heat treatment process is: firstly, heating to 600 DEG C at a heating rate of 5 DEG C / min and keeping for 2h to perform annealing treatment; then, heating to 1140 DEG C and keeping for 2h to perform solid solution treatment; aging heat treatment is heating from room temperature to 850 DEG C, keeping for 8h.

[0059] Figure 8 are the grain boundary and intracrystalline precipitated phase morphologies of the heat treated additive manufacturing alloy prepared in Comparative Example 4, wherein (a) is the grain boundary precipitated phase morphology, and (b) is the intracrystalline precipitated phase morphology. Figure 8 It can be seen that the size of the γ' strengthening phase is concentrated in 70-80nm, and the morphology is original shape.

[0060] The high temperature tensile property test results of the heat treated alloys prepared in the examples and comparative examples are shown in Table 1.

[0061]

[0062] According to the data in Table 1 and Table 2, it can be seen that the strength and plasticity of the additive manufacturing Re-containing nickel-based high-temperature alloy in the deposition state in the embodiment of the application are greatly improved after the heat treatment of "hot isostatic pressing + annealing + high-temperature short-time solid solution treatment + aging treatment" proposed in the embodiment of the application, compared with the deposition state alloy, and the problem of general performance decline and difficult simultaneous improvement of strength and plasticity of the additive manufacturing high-temperature alloy after heat treatment is solved. At the same time, it can be shown from Comparative Examples 1-3 that the heat treatment process steps and the additive manufacturing Re-containing nickel-based high-temperature alloy with the composition selected in the application are very matched.

[0063] The scheme of the embodiment of the application improves the density of the additive manufacturing nickel-based high-temperature alloy by hot isostatic pressing; eliminates the new stress introduced after hot isostatic pressing by stress relief annealing; improves the element uniformity of the alloy by optimizing the solid solution treatment process; and controls the volume fraction and morphology of the strengthening phase by two-stage aging, thereby providing an innovative solution for the heat treatment of additive manufacturing high-temperature alloys.

[0064] The above description is only a preferred embodiment of the application, and does not limit the application in any form. Any simple modification, equivalent change and modification of the above embodiment according to the technical essence of the application still belongs to the scope of the technical solution of the application.

Claims

1. A heat treatment method for additive manufacturing of a Re-containing nickel-based superalloy, characterized in that, It comprises the following steps: hot isostatic pressing treatment: the additive manufacturing Re-containing nickel-based superalloy in as-deposited state is subjected to hot isostatic pressing treatment for eliminating the crack and hole defects of the additive manufacturing Re-containing nickel-based superalloy in as-deposited state, and an alloy after hot isostatic pressing treatment is obtained; wherein, the additive manufacturing Re-containing nickel-based superalloy in as-deposited state comprises the following chemical components in percentage by weight: Cr: 2-8wt%, C: 0.01-0.1wt%, Mo: 2-5wt%, W: 5-8wt%, Co: 7-11wt%, Al: 3-8wt%, Ti: 1-3wt%, Ta: 4-8wt%, B: 0.03-0.1wt%, Re: 0-4wt%, and the balance of Ni; stress relief annealing treatment: the alloy after hot isostatic pressing treatment is subjected to stress relief annealing treatment, and an alloy after stress relief annealing treatment is obtained; solution treatment: the alloy after stress relief annealing treatment is subjected to solution treatment, and an alloy after solution treatment is obtained; wherein, the solution treatment temperature is 1280-1330℃, and the solution treatment time is 0.5-2h; aging treatment: the alloy after solution treatment is subjected to aging treatment, and an additive manufacturing Re-containing nickel-based superalloy in heat-treated state is obtained.

2. The heat treatment method of additively manufactured Re-containing nickel- based superalloy of claim 1, wherein, The preparation steps of the additive manufacturing Re-containing nickel-based superalloy in as-deposited state comprise: using Re-containing nickel-based superalloy powder as raw material, a Re-containing nickel-based superalloy sample in as-deposited state is printed by selective laser melting technology; Preferably, the additive manufacturing Re-containing nickel-based superalloy in as-deposited state is a molten pool morphology, wherein, the width of the molten pool is about 70-80μm; Preferably, the particle size of the Re-containing nickel-based superalloy powder is 15-53μm.

3. The heat treatment method of additively manufactured Re-containing nickel- based superalloy of claim 2, wherein, The parameter settings of the selective laser melting printing are as follows: laser power is 180-280W, scanning speed is 800-1100mm / s, printing layer thickness is 40-50μm, track spacing is 70-90μm, and layer-to-layer angle is 90°.

4. Heat treatment method of additively manufactured Re-containing nickel-based superalloy according to any one of claims 1 to 3, characterized in that, In the step of hot isostatic pressing treatment: the hot isostatic pressing treatment temperature is 1180-1210℃, the hot isostatic pressing treatment pressure is 170-180MPa, and the hot isostatic pressing treatment time is 2-4h.

5. The heat treatment method of additively manufactured Re-containing nickel- based superalloy according to any one of claims 1 to 4, characterized in that, In the step of stress relief annealing treatment: the stress relief annealing treatment temperature is 600-700℃, and the stress relief annealing treatment time is 4-10h.

6. The heat treatment method of additively manufactured Re-containing nickel- based superalloy according to any one of claims 1 to 5, characterized in that, In the step of solution treatment: after the high-temperature heat treatment furnace is heated to the solution treatment temperature, the alloy after stress relief annealing treatment is put into the high-temperature heat treatment furnace for solution heat treatment, and after cooling, the alloy after solution treatment is obtained; preferably, the cooling mode is selected as air cooling mode.

7. The heat treatment method of additively manufactured Re-containing nickel- based superalloy according to any one of claims 1 to 6, characterized in that, The aging treatment comprises: primary aging treatment: the alloy after solution treatment is subjected to primary aging treatment, and after cooling, an alloy after primary aging treatment is obtained; wherein, the primary aging treatment temperature is 1100-1120℃, the primary aging treatment time is 2-4h, and preferably, the cooling mode is selected as air cooling mode; The alloy after the primary aging treatment is subjected to secondary aging treatment, and after cooling, a heat-treated state additive manufacturing Re-containing nickel-based superalloy is obtained; wherein the temperature of the secondary aging treatment is 850-870℃, and the time of the secondary aging treatment is 20-24h.

8. A heat treated as-processed additively manufactured Re-containing nickel- based superalloy, characterized in that, In the heat-treated state additive manufacturing Re-containing nickel-based superalloy: the grain boundaries and the grains are both dispersedly distributed with granular carbides; wherein the size of the granular carbides at the grain boundaries is 0.2-2.2μm, and the size of the intragranular carbides is about 0.1-0.4μm; cubic γ′ phases are uniformly precipitated in the grains, and the size of the cubic γ′ phases is 350-450nm; and Re elements are solid-solved in the γ matrix to play a solid-solution strengthening role.

9. The heat treated as- built Re-containing nickel-base superalloy of claim 8, wherein, At room temperature, the heat-treated state additive manufacturing Re-containing nickel-based superalloy has a tensile strength of 1300-1350MPa, a yield strength of 950-1000MPa, and an elongation of 15%-20%; and / or At a tensile test condition of 900℃, the heat-treated state additive manufacturing Re-containing nickel-based superalloy has a tensile strength of 850-870MPa, a yield strength of 750-800MPa, and an elongation of 5%-10%.

10. The heat treated as- built Re-containing nickel-base superalloy of claim 8 or 9, wherein, The heat-treated state additive manufacturing Re-containing nickel-based superalloy is obtained by subjecting the as-deposited additive manufacturing Re-containing nickel-based superalloy to the heat treatment method of the heat-treated state additive manufacturing Re-containing nickel-based superalloy according to any one of claims 1-7.

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