CN113477942B - SLM-based preparation method of high-strength high-plasticity Inconel718 alloy - Google Patents

Abstract

A preparation method of an SLM-based high-strength high-plasticity Inconel718 alloy comprises the following steps: s1, selective laser melting and forming: printing an Inconel718 alloy blank by a selective laser melting method, and sequentially carrying out step S2 isostatic pressing heat treatment, step S3 stress relief annealing treatment, step S4 solution treatment and step S5 double-stage aging treatment on the Inconel718 alloy blank; the hot isostatic pressing heat treatment temperature is 1165-1170 ℃, the pressure is 125-135 Mpa, and the time is 210-270 min; the stress relief annealing temperature is 790-810 ℃, and the time is 20-40 min; the temperature of the solution treatment is 940-960 ℃, and the time is 20-40 min; the temperature of the first-stage aging treatment of the two-stage aging treatment is 750-770 ℃, the time is 470-490 min, the temperature of the second-stage aging treatment is 640-660 ℃, and the time is 470-490 min. The Inconel718 alloy prepared by the method has the advantages of strength, plasticity and hardness, excellent comprehensive mechanical properties and capability of expanding the application of the Inconel718 alloy to the field of more precise and complex structures.

Description

Preparation method of high strength and high plasticity Inconel718 alloy based on SLM

technical field

The invention relates to a preparation method of a high-strength and high-plastic Inconel718 alloy based on SLM, and belongs to the technical field of alloy additive manufacturing.

Background technique

Superalloy is a high-performance material that can work for a long time at temperatures above 600°C and under certain stress conditions. Inconel718 alloy is a precipitation-strengthened nickel-based superalloy, which is widely used in aerospace due to its high strength at 650 °C, excellent fatigue and creep resistance, and good oxidation and corrosion resistance. , nuclear power and energy fields.

The mechanical properties of Inconel718 alloy mainly depend on its precipitation phases, including: γ"(Ni ₃ Nb) phase, γ'(Ni ₃ (Al,Ti,Nb)), δ(Ni ₃ Nb), Laves equal. γ"( The Ni ₃ Nb) phase is the main strengthening phase, and the γ'(Ni ₃ (Al,Ti,Nb)) phase is the auxiliary strengthening phase. An appropriate amount of δ(Ni ₃ Nb) phase can pin the grain boundaries and hinder the migration of grain boundaries, and can improve the impact toughness and creep properties of the alloy.

The preparation of traditional Inconl718 alloy parts mainly includes casting and forging. After years of development and improvement, the performance of castings and forgings has been greatly improved, but the inherent defects of the two methods are still unavoidable. There are still serious segregation of elements, coarse grains, and porosity in castings. Although the performance of forgings is higher than that of as-cast, it is difficult to form parts with complex shapes due to process limitations, and there are defects such as black spots and white spots. . Moreover, the above two processing methods belong to subtractive manufacturing, which has high cost and long manufacturing cycle, and is difficult to manufacture components with complex structures.

Additive Manufacturing (AM) is a process of building objects layer by layer from 3D model data. This blank and mold-free manufacturing method could bring new design flexibility to the industry, reducing energy usage and time-to-market. Laser selective melting SLM (Selective Laser Melting) forming method is a commonly used additive manufacturing method. The preparation of Inconel718 alloy by the SLM forming method not only solves the forming problem of complex parts, but also has high forming quality. However, the metal SLM forming has the characteristics of rapid solidification. The extremely high cooling rate makes the formed Inconel718 alloy parts generally have large local thermal stress. The segregation of Nb element causes a large number of brittle Laves phase precipitation, and the precipitation of γ", γ' and δ phases. Defects such as microcracks are easily produced in the boundary remelting zone of the suppressed and molten track, and the above-mentioned defects are generally improved with the follow-up heat treatment, but the effect is not satisfactory. The prior art also does not have a preparation method that can prepare both strength and plasticity at the same time. , hardness and other mechanical properties of Inconel718 alloy, which limits its application in many fields.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a preparation method of high strength and high plasticity Inconel718 alloy based on SLM, the Inconel718 alloy prepared by the method has both strength, plasticity and hardness, has excellent comprehensive mechanical properties, and can expand the application of Inconel718 alloy to more sophisticated and complex structures.

The technical scheme adopted by the present invention to achieve the purpose of the invention is: a preparation method of a high-strength and high-plastic Inconel718 alloy based on SLM, comprising the following steps:

S1. Laser selective melting molding: Inconel718 alloy blanks are printed by laser selective melting;

S2. Isostatic pressing heat treatment: place the Inconel718 alloy blank formed by laser selective melting in the isostatic pressing heat treatment equipment, vacuumize, and perform isostatic pressing heat treatment under vacuum conditions. The hot isostatic pressing heat treatment temperature is 1165 ℃ ~ 1170 ℃, the pressure is 125～135Mpa, the time is 210min～270min, after isostatic pressing heat treatment, argon gas is introduced into the isostatic pressing heat treatment equipment to rapidly cool to room temperature;

S3. Stress relief annealing treatment: place the Inconel718 alloy blank after isostatic pressing heat treatment in the high temperature heating inner chamber of the heat treatment furnace, and perform stress relief annealing under the protection of argon atmosphere. The stress relief annealing temperature is 790℃～810℃ ℃, the time is 20min～40min;

S4. Solution treatment: After the stress relief annealing operation is completed, keep the high temperature heating inner chamber protected in an argon atmosphere, and increase the temperature of the heating inner chamber to perform solution treatment on the Inconel718 alloy blank after stress relief annealing treatment , the solution treatment temperature is 940 ℃ ~ 960 ℃, the time is 20min ~ 40min, after the solution treatment, the heat treatment furnace is filled with argon and rapidly cooled to below 500 ℃;

S5. Double-stage aging treatment: place the solution-treated Inconel718 alloy blank in the high-temperature heating inner chamber of the heat treatment furnace, and carry out double-stage aging treatment under the protection of argon atmosphere. The temperature of the first-stage aging treatment is 750℃～ 770℃, the time is 470min～490min, the temperature of the secondary aging treatment is 640℃～660℃, and the time is 470min～490min, after the aging treatment, the heat treatment furnace is filled with argon and rapidly cooled to below 200℃, and the furnace is released, that is, the high strength is completed. Preparation of high plasticity Inconel718 alloy.

Compared with the prior art, the beneficial effects of the present invention are:

1. The present invention adopts laser selective melting and printing of Inconel718 alloy blanks, which has high material utilization rate, material cost saving, more flexible production process, high forming quality, and solves the forming problem of complex parts.

2. In the present invention, by performing isostatic pressure heat treatment at a temperature of 1165 ℃ to 1170 ℃ and a pressure of 125 to 135 Mpa for 210 to 270 minutes on the Inconel718 alloy blank formed by laser selective melting, the microscopic pores inside the sample can be eliminated, and the strain-induced boundary migration can be eliminated. Dissolve the brittle Laves phase, thereby reducing element segregation, uniform structure, and promoting grain recrystallization.

3. In the present invention, the Inconel718 alloy blank after isostatic pressing heat treatment is subjected to stress relief annealing at a temperature of 790°C to 810°C and a time of 20min to 40min, so that the decomposition and rapid migration of the interface with special orientation can be achieved. It promotes the nucleation and growth of the twin boundary, and finally forms a "cluster" annealing twin boundary, and preferentially precipitates δ phase at the grain boundary and the twin boundary to pin and strengthen the grain boundary.

4. In the present invention, after the stress relief annealing treatment, the temperature of 940℃～960℃ is used for solution treatment for 20min～40min, which can make the carbide, γ″ phase and γ′ in the matrix dissolve equally to obtain a uniform supersaturated solid solution, which is convenient for During aging, fine-grained and uniformly distributed carbides, γ″ phase and γ' phase and other strengthening phases are re-precipitated. After solution treatment, supersaturated solid solution can be obtained by filling with nitrogen and rapidly cooling.

5. The present invention performs double-stage aging treatment on the Inconel718 alloy blank after solution treatment, selects a higher aging treatment temperature, and controls the temperature and time of the first-stage aging treatment and the second-stage aging treatment, so that the precipitation in the intragranular matrix is made. The strengthening phase γ" phase and γ' phase, high aging temperature combined with rapid cooling operation, can keep the alloy grain morphology fine and uniform, improve the yield strength and tensile strength of the material, and the rapid cooling operation can improve the degree of supercooling. Conducive to more efficient precipitation of strengthening phase.

In a word, the present invention firstly selects and melts an Inconel718 alloy blank with uniform structure, fine grain size and high density through laser selection, and then combines high temperature isostatic pressing heat treatment, stress relief annealing treatment, solid solution treatment, and double-stage aging treatment to eliminate the The brittle Laves phase and the internal micro-pores in the Inconel718 alloy blanks formed by laser selective melting are studied, which can effectively promote the precipitation of the strengthening phase, generate twin grain boundaries and generate δ phase at the grain boundaries, so that the prepared alloy can be prepared without sacrificing strength. On the basis, the plasticity is greatly improved. Compared with the alloy blank before heat treatment, the invention has the advantages that the tensile strength at room temperature is increased by 37.06%, the yield strength at room temperature is increased by 70.14%, the hardness at room temperature is increased by 61.18%, and the elongation after fracture is higher than the forging standard (12.00%), reaching 23.10%. That is, the preparation method of the present invention significantly improves the room temperature strength of the Inconel718 alloy while retaining its ductility to a large extent, and obtains the Inconel718 alloy with excellent comprehensive mechanical properties, which is of great significance for widening the application range of the Inconel718 alloy.

Further, in the step S1 of the present invention, the printing parameters of the laser selective melting molding and printing of the Inconel718 alloy blank are: the printing power is 190W～210W, the layer height is 29μm～31μm, the scanning speed is 890mm/s～910mm/s, and the scanning distance is 0.98mm～1.2mm.

Experiments have verified that the above SLM process parameters can form Inconel718 alloy blanks with uniform structure, fine grains, high density and complex shapes.

Further, the particle size of the Inconel718 alloy powder used in the laser selective melting and forming in step S1 of the present invention is 45-60 μm.

Experiments have verified that the particle size of 45-60μm powder has a good balance in fluidity, splash inhibition and melting uniformity. The Inconel718 alloy blank is obtained by using 8 alloy powder with a powder particle size of 45-60μm for laser selective melting and molding The forming quality is good, and the Inconel718 alloy with excellent mechanical properties can be obtained in combination with the subsequent treatment.

Further, the isostatic pressing heat treatment in step S2 of the present invention is performed under vacuum conditions not higher than 6.67×10 ⁻² Pa.

Further, the time of the hot isostatic pressing heat treatment in step S2 of the present invention is 235min-245min.

Experiments have verified that the hot isostatic pressing heat treatment for 235min-245min can ensure that the Laves phase can be fully dissolved and the grain size can be controlled to be too large.

Further, the temperature of the stress relief annealing treatment in step S3 of the present invention is 795° C.˜805° C., and the time is 25 min˜35 min.

Experiments have verified that the temperature and time of the stress relief annealing treatment are beneficial to generate more twin boundaries and at the same time precipitate δ phase at the grain boundaries to pin and strengthen the grain boundaries.

Further, the temperature of the solution treatment in step S4 of the present invention is 945°C to 955°C, and the time is 25min to 35min.

Experiments have verified that the temperature and time of the above-mentioned solution treatment can ensure that the supersaturated solid solution is fully formed, and at the same time, the dissolution of the δ phase at the grain boundary and the regrowth of the grains can be avoided.

Further, in the step S4 of the present invention, after the stress relief annealing operation is completed, the high temperature heating inner chamber is kept protected in an argon atmosphere, and the heating inner chamber is raised at a temperature rise rate of 8°C/min to 10°C/min. The temperature of the Inconel718 alloy blank after stress relief annealing treatment is solution treatment.

Further, in the double-stage aging treatment in step S5 of the present invention, the temperature of the first-stage aging treatment is 755°C～765°C, and the time is 475min～485min, and the temperature of the second-stage aging treatment is 645°C～655°C, and the time is 475min～485min .

The use of the above-mentioned aging treatment temperature and time is beneficial to control the morphology of the γ" phase and the γ' phase, and keep the morphology fine and uniform.

Further, in the double-stage aging treatment in step S5 of the present invention, after the first-stage aging treatment, the temperature of the heating inner chamber is controlled to be furnace-cooled to the second-stage aging treatment temperature at a cooling rate of 40°C/h to 60°C/h.

The above cooling rate can not only avoid stress concentration and micro-cracks, but also help to control the effect of the second-stage aging, and at the same time ensure the production efficiency of heat treatment.

Description of drawings

FIG. 1 is a 1000 times optical microscope view of the Inconel718 alloy blank prepared in step S1 in the first embodiment of the present invention.

FIG. 2 is a 100 times optical microscope view of the high-strength and high-plastic Inconel718 alloy prepared in Example 1 of the present invention.

FIG. 3 is a backscattered electron diffraction twin boundary diagram of the high-strength and high-plastic Inconel718 alloy prepared in Example 1 of the present invention.

FIG. 4 is a 100 times optical microscope view of the high-strength and high-plastic Inconel718 alloy prepared in Example 2 of the present invention.

FIG. 5 is a stress-strain diagram of backscattered electron diffraction of the high-strength and high-plastic Inconel718 alloy prepared in Example 2 of the present invention.

6 is a scanning electron microscope image of the high-strength and high-plastic Inconel718 alloy prepared in Example 1 of the present invention.

7 is a scanning electron microscope image of the high-strength and high-plastic Inconel718 alloy prepared in Example 2 of the present invention.

FIG. 8 is a tensile curve diagram of the high-strength and high-plastic Inconel718 alloy prepared in the first and second embodiments of the present invention.

Detailed ways

Example 1

A preparation method of a high-strength and high-plastic Inconel718 alloy based on SLM, comprising the following steps:

S1. Laser selective melting molding: Inconel718 alloy blanks are printed by laser selective melting. The particle size of Inconel718 alloy powder used in laser selective melting molding is 45-60 μm. The printing parameters are: printing power of 200W, layer height of 30 μm, scanning The speed is 900mm/s and the scanning interval is 1mm; take the printed Inconel718 alloy blank sample and observe its microstructure, as shown in Figure 1;

S2. Isostatic pressing heat treatment: place the Inconel718 alloy blank formed by laser selective melting in the isostatic pressing heat treatment equipment, vacuumize, and perform isostatic pressing heat treatment under the vacuum condition of not higher than 6.67×10 ^-2 Pa. The temperature of isostatic pressing heat treatment is 1165℃, the pressure is 130Mpa, and the time is 240min. After the isostatic pressing heat treatment, argon gas is introduced into the isostatic pressing heat treatment equipment to rapidly cool to room temperature;

S3. Stress relief annealing treatment: The Inconel718 alloy blank after isostatic pressing heat treatment is placed in the high temperature heating inner chamber of the heat treatment furnace, and stress relief annealing is carried out under the protection of argon atmosphere. The stress relief annealing temperature is 800 ℃, and the time is 30min;

S4, solution treatment: after the stress relief annealing treatment operation is completed, keep the high temperature heating inner chamber protected in an argon atmosphere, and increase the temperature of the heating inner chamber at a heating rate of 8°C/min. The Inconel718 alloy blanks are solution-treated, the solution-treatment temperature is 950°C, and the time is 30min. After the solution-treatment, the heat treatment furnace is filled with argon and rapidly cooled to below 500°C;

S5. Double-stage aging treatment: The Inconel718 alloy blank after solution treatment is placed in the high-temperature heating inner chamber of the heat treatment furnace, and the double-stage aging treatment is carried out under the protection of argon atmosphere. The temperature of the first-stage aging treatment is 760 ℃, The time is 480min. After the first-level aging treatment, the temperature of the heating inner chamber is controlled to cool down to the second-level aging treatment temperature of 650℃ at a cooling rate of 50℃/h. The second-level aging treatment time is 480min. Filling with argon gas is quickly cooled to below 200 ° C, and the furnace is released, that is, the preparation of high-strength and high-plastic Inconel718 alloy is completed.

Embodiment 2

A preparation method of a high-strength and high-plastic Inconel718 alloy based on SLM, comprising the following steps:

S1. Laser selective melting molding: Inconel718 alloy blanks are printed by laser selective melting. The particle size of Inconel718 alloy powder used in laser selective melting molding is 45-60 μm. The printing parameters are: printing power of 200W, layer height of 30 μm, scanning The speed is 900mm/s and the scanning distance is 1mm;

S2. Isostatic pressing heat treatment: place the Inconel718 alloy blank formed by laser selective melting in the isostatic pressing heat treatment equipment, vacuumize, and perform isostatic pressing heat treatment under the vacuum condition of not higher than 6.67×10 ^-2 Pa. The temperature of isostatic pressing heat treatment is 1170℃, the pressure is 130Mpa, and the time is 220min. After isostatic pressing heat treatment, argon gas is introduced into the isostatic pressing heat treatment equipment to rapidly cool to room temperature;

S3. Stress relief annealing treatment: Place the Inconel718 alloy blank after isostatic pressing heat treatment in the high temperature heating inner chamber of the heat treatment furnace, and perform stress relief annealing under the protection of argon atmosphere. The stress relief annealing temperature is 810°C, and the time is 30min;

S4, solution treatment: after the stress relief annealing treatment operation is completed, keep the high temperature heating inner chamber protected in an argon atmosphere, and increase the temperature of the heating inner chamber at a heating rate of 8°C/min. Inconel718 alloy blanks are solution treated, the solution treatment temperature is 950℃, and the time is 40min. After the solution treatment, the heat treatment furnace is filled with argon and rapidly cooled to below 500℃;

S5. Double-stage aging treatment: The Inconel718 alloy blank after solution treatment is placed in the high-temperature heating inner chamber of the heat treatment furnace, and the double-stage aging treatment is carried out under the protection of argon atmosphere. The temperature of the first-stage aging treatment is 760 ℃, The time is 470min. After the primary aging treatment, the temperature of the heating inner chamber is controlled to be cooled to the secondary aging treatment temperature of 650 °C at a cooling rate of 60℃/h. The secondary aging treatment time is 480min. Filling with argon gas is quickly cooled to below 200 ° C, and the furnace is released, that is, the preparation of high-strength and high-plastic Inconel718 alloy is completed.

The high-strength and high-plastic Inconel718 alloy samples prepared in Example 1 and Example 2 were used for characterization.

Figure 1 is a 1000x optical microscope image of the Inconel718 alloy blank prepared in step S1 of Example 1, showing the microstructure of the Inconel718 alloy blank. As can be seen from the figure, the microstructure of the alloy matrix consists of fine cellular crystals and fine The composition of long columnar crystals can also see the obvious printed melt pool boundary, which has an adverse effect on the mechanical properties.

FIG. 2 and FIG. 4 are 100 times optical microscope images of the high-strength and high-plastic Inconel718 alloy prepared in Example 1 and Example 2, respectively. It can be seen from the figure that after the heat treatment in steps S2-S5, the alloy grains are obviously recrystallized, the grain size is significantly larger than that of the original sample, and a large number of twinned crystals can be observed inside the grains and at the grain boundaries. form.

Figure 3 is the backscattered electron diffraction twin grain boundary diagram of the high-strength and high-plastic Inconel718 alloy prepared in Example 1. It can be seen from the figure that after the heat treatment in steps S2-S5, a large number of twin grain boundaries (black and black) are formed in the microstructure of the alloy matrix. bold lines).

FIG. 5 is a stress-strain diagram of backscattered electron diffraction of the high-strength and high-plastic Inconel718 alloy prepared in Example 2. FIG. It can be seen from the figure that after the heat treatment in steps S2-S5, the internal stress (high-bright white point area) in the microstructure of the alloy matrix has been basically eliminated.

FIG. 6 and FIG. 7 are scanning electron microscope images of the high-strength and high-plastic Inconel718 alloy prepared in Example 1 and Example 2, respectively. It can be seen from the figure that after the heat treatment in steps S2-S5, the microstructure and grain boundaries of the alloy matrix are uniformly distributed with short rod-shaped and fine needle-shaped δ phases, and a small amount of MC phase is also distributed on the matrix. The MC phase composition is TiC, NbC The face-centered cubic carbide phase has stable properties and high melting point, but the number is very small. It has ceramic properties such as high hardness and high melting point, which plays a certain role in strengthening the second phase of the alloy.

It can be seen from the figure that after the hot isostatic pressing at 1160 °C and 130 MPa, the laser scanning boundary of the original sample disappeared, the dendrites and cellular substructures were replaced by recrystallized grains, and a large amount of brittleness precipitated between the dendrites. The Laves phase basically dissolves and releases the internal stress accumulated during rapid prototyping of the material (as shown in Figure 5). At this time, the grain boundary moves rapidly under the action of a high temperature of 1160 °C, starts to recrystallize, and generates annealing twins. Under the action of 130MPa pressure, the alloy is slightly deformed, and the interaction of dislocations with the annealing twin boundaries in the alloy leads to a large number of a/6<112> incomplete dislocations on the annealing twin boundaries, resulting in continuous interfaces (grain boundaries and annealing twin boundaries). twin boundary) gradually evolved into a discontinuous interface; in the subsequent stress relief annealing process at 790 °C ~ 810 °C, the decomposition and rapid migration of the interface with special orientations promoted the nucleation and growth of the twin boundary, and finally formed "clusters". "annealing twin grain boundaries (as shown in Figure 2, Figure 3 and Figure 4), and preferentially precipitates delta phases (as shown in Figures 6 and 7) at the grain boundaries and twin boundaries to pin and strengthen the grain boundaries to improve the overall mechanical properties, and inhibit the growth of grains during the next solid solution.

The precipitation phase of the high-strength and high-plastic Inconel718 alloy prepared in Example 1 and Example 2 was analyzed by X-ray diffraction, and δ phase, γ" phase and γ' phase were detected, and the micro-Vickers hardness tester and electronic universal testing machine were used to test their Mechanical properties, it is found that the room temperature hardness of the high-strength and high-plastic Inconel718 alloy prepared in Example 1 is 458HV, the tensile strength at room temperature is 1395MPa, the yield strength at room temperature is 1138MPa, and the elongation after fracture at room temperature is 21.80%; The room temperature hardness of the high plasticity Inconel718 alloy is 472HV, the room temperature tensile strength is 1433MPa, the room temperature yield strength is 1184MPa, and the room temperature elongation after fracture is 22.90%. Figure 8.

To sum up, the Inconel718 alloy sample prepared according to the preparation method of the present invention basically eliminates the internal microporosity and element segregation, the twin crystals are evenly distributed, and the second phase is uniformly precipitated. The elongation is higher than the forging standard. It can meet the requirements of high strength and high plasticity of structural parts of Inconel718 alloy.

Embodiment 3

A preparation method of a high-strength and high-plastic Inconel718 alloy based on SLM, comprising the following steps:

S1. Laser selective melting molding: Inconel718 alloy blanks are printed by laser selective melting. The particle size of Inconel718 alloy powder used in laser selective melting molding is 45-60 μm. The printing parameters are: printing power of 190W, layer height of 31 μm, scanning The speed is 890mm/s, and the scanning distance is 0.98mm; take the printed Inconel718 alloy blank sample;

S2. Isostatic pressing heat treatment: place the Inconel718 alloy blank formed by laser selective melting in the isostatic pressing heat treatment equipment, vacuumize, and perform isostatic pressing heat treatment under the vacuum condition of not higher than 6.67×10 ^-2 Pa. The temperature of isostatic pressing heat treatment is 1168℃, the pressure is 125Mpa, and the time is 270min. After isostatic pressing heat treatment, argon gas is introduced into the isostatic pressing heat treatment equipment to rapidly cool to room temperature;

S3. Stress relief annealing treatment: Place the Inconel718 alloy blank after isostatic pressing heat treatment in the high temperature heating inner chamber of the heat treatment furnace, and perform stress relief annealing under the protection of argon atmosphere. The stress relief annealing temperature is 790 °C, and the time is 40min;

S4, solution treatment: after the stress relief annealing treatment operation is completed, keep the high temperature heating inner chamber protected in an argon atmosphere, and increase the temperature of the heating inner chamber at a heating rate of 8°C/min. The Inconel718 alloy blanks were solution treated at a temperature of 940°C for 40 minutes. After solution treatment, the heat treatment furnace was filled with argon and rapidly cooled to below 500°C;

S5. Double-stage aging treatment: The Inconel718 alloy blank after solution treatment is placed in the high-temperature heating inner chamber of the heat treatment furnace, and double-stage aging treatment is carried out under the protection of argon atmosphere. The temperature of the first-stage aging treatment is 750 ℃, The time is 490min. After the first-level aging treatment, the temperature of the heating inner chamber is controlled to cool down to the second-level aging treatment temperature of 640℃ at a cooling rate of 50℃/h. The second-level aging treatment time is 490min. Filling with argon gas is quickly cooled to below 200 ° C, and the furnace is released, that is, the preparation of high-strength and high-plastic Inconel718 alloy is completed.

Embodiment 4

A preparation method of a high-strength and high-plastic Inconel718 alloy based on SLM, comprising the following steps:

S1. Laser selective melting and molding: Inconel718 alloy blanks are printed by laser selective melting. The particle size of Inconel718 alloy powder used in laser selective melting and molding is 45-60 μm. The printing parameters are: printing power of 210W, layer height of 29 μm, scanning The speed is 910mm/s, and the scanning distance is 1.2mm; take the printed Inconel718 alloy blank sample;

S2. Isostatic pressing heat treatment: place the Inconel718 alloy blank formed by laser selective melting in the isostatic pressing heat treatment equipment, vacuumize, and perform isostatic pressing heat treatment under the vacuum condition of not higher than 6.67×10 ^-2 Pa. The temperature of isostatic pressing heat treatment is 1168℃, the pressure is 135Mpa, and the time is 210min. After isostatic pressing heat treatment, argon gas is poured into the isostatic pressing heat treatment equipment to rapidly cool to room temperature;

S3. Stress relief annealing treatment: The Inconel718 alloy blank after isostatic pressing heat treatment is placed in the high temperature heating inner chamber of the heat treatment furnace, and stress relief annealing is carried out under the protection of argon atmosphere. The stress relief annealing temperature is 805 ℃, and the time is 25min;

S4, solution treatment: after the stress relief annealing treatment operation is completed, keep the high temperature heating inner chamber protected in an argon atmosphere, and increase the temperature of the heating inner chamber at a heating rate of 8°C/min. The Inconel718 alloy blanks were solution treated at a temperature of 960°C for 20 minutes. After solution treatment, the heat treatment furnace was filled with argon and rapidly cooled to below 500°C;

S5. Double-stage aging treatment: The Inconel718 alloy blank after solution treatment is placed in the high-temperature heating inner chamber of the heat treatment furnace, and the double-stage aging treatment is carried out under the protection of an argon atmosphere. The temperature of the first-stage aging treatment is 770 ℃, The time is 470min. After the first-stage aging treatment, the temperature of the heating inner chamber is controlled to cool down to the second-stage aging treatment temperature of 660°C at a cooling rate of 40℃/h. The second-stage aging treatment time is 470min. Filling with argon gas is quickly cooled to below 200 ° C, and the furnace is released, that is, the preparation of high-strength and high-plastic Inconel718 alloy is completed.

Embodiment 5

A preparation method of a high-strength and high-plastic Inconel718 alloy based on SLM, comprising the following steps:

S1. Laser selective melting molding: Inconel718 alloy blanks are printed by laser selective melting. The particle size of Inconel718 alloy powder used in laser selective melting molding is 45-60 μm. The printing parameters are: printing power of 200W, layer height of 30 μm, scanning The speed is 900mm/s, and the scanning interval is 1mm; take the printed Inconel718 alloy blank sample;

S2. Isostatic pressing heat treatment: place the Inconel718 alloy blank formed by laser selective melting in the isostatic pressing heat treatment equipment, vacuumize, and perform isostatic pressing heat treatment under the vacuum condition of not higher than 6.67×10 ^-2 Pa. The temperature of isostatic pressing heat treatment is 1168℃, the pressure is 130Mpa, and the time is 235min. After the isostatic pressing heat treatment, argon gas is poured into the isostatic pressing heat treatment equipment to rapidly cool to room temperature;

S3. Stress relief annealing treatment: The Inconel718 alloy blank after isostatic pressing heat treatment is placed in the high temperature heating inner chamber of the heat treatment furnace, and stress relief annealing is carried out under the protection of argon atmosphere. The stress relief annealing temperature is 795 ℃, and the time is 35min;

S4, solution treatment: after the stress relief annealing treatment operation is completed, keep the high temperature heating inner chamber protected in an argon atmosphere, and increase the temperature of the heating inner chamber at a heating rate of 8°C/min. Inconel 718 alloy blanks are solution treated, the solution treatment temperature is 945℃, and the time is 35min. After the solution treatment, the heat treatment furnace is filled with argon and rapidly cooled to below 500℃;

S5. Double-stage aging treatment: The Inconel718 alloy blank after solution treatment is placed in the high-temperature heating inner chamber of the heat treatment furnace, and the double-stage aging treatment is carried out under the protection of an argon atmosphere. The temperature of the first-stage aging treatment is 755 ℃, The time is 485min. After the primary aging treatment, the temperature of the heating inner chamber is controlled to cool down to the secondary aging treatment temperature of 645 °C at a cooling rate of 50℃/h. The secondary aging treatment time is 485min. Filling with argon gas is quickly cooled to below 200 ° C, and the furnace is released, that is, the preparation of high-strength and high-plastic Inconel718 alloy is completed.

Embodiment 6

A preparation method of a high-strength and high-plastic Inconel718 alloy based on SLM, comprising the following steps:

S1. Laser selective melting molding: Inconel718 alloy blanks are printed by laser selective melting. The particle size of Inconel718 alloy powder used in laser selective melting molding is 45-60 μm. The printing parameters are: printing power of 200W, layer height of 30 μm, scanning The speed is 900mm/s, and the scanning interval is 1mm; take the printed Inconel718 alloy blank sample;

S2. Isostatic pressing heat treatment: place the Inconel718 alloy blank formed by laser selective melting in the isostatic pressing heat treatment equipment, vacuumize, and perform isostatic pressing heat treatment under the vacuum condition of not higher than 6.67×10 ^-2 Pa. The temperature of isostatic pressing heat treatment is 1168℃, the pressure is 130Mpa, and the time is 245min. After the isostatic pressing heat treatment, argon gas is introduced into the isostatic pressing heat treatment equipment to rapidly cool to room temperature;

S3. Stress relief annealing treatment: Place the Inconel718 alloy blank after isostatic pressing heat treatment in the high temperature heating inner chamber of the heat treatment furnace, and perform stress relief annealing under the protection of argon atmosphere. The stress relief annealing temperature is 810°C, and the time is 20min;

S4, solution treatment: after the stress relief annealing treatment operation is completed, keep the high temperature heating inner chamber protected in an argon atmosphere, and increase the temperature of the heating inner chamber at a heating rate of 8°C/min. Inconel718 alloy blanks are solution treated, the solution treatment temperature is 955℃, and the time is 25min. After the solution treatment, the heat treatment furnace is filled with argon and rapidly cooled to below 500℃;

S5. Double-stage aging treatment: The Inconel718 alloy blank after solution treatment is placed in the high-temperature heating inner chamber of the heat treatment furnace, and the double-stage aging treatment is carried out under the protection of an argon atmosphere. The temperature of the first-stage aging treatment is 765 ℃, The time is 475min. After the first-stage aging treatment, the temperature of the heating inner chamber is controlled to cool down to the second-stage aging treatment temperature of 655°C at a cooling rate of 50℃/h. The second-stage aging treatment time is 475min. Filling with argon gas is quickly cooled to below 200 ° C, and the furnace is released, that is, the preparation of high-strength and high-plastic Inconel718 alloy is completed.

Claims (10)

1. A preparation method of an Inconel718 alloy with high strength and high plasticity based on SLM is characterized by comprising the following steps:

s1, selective laser melting and forming: printing an Inconel718 alloy blank by a selective laser melting method;

s2, isostatic pressing heat treatment: placing the Inconel718 alloy blank subjected to selective laser melting molding in isostatic pressure heat treatment equipment, vacuumizing, performing isostatic pressure heat treatment under a vacuum condition, wherein the temperature of the isostatic pressure heat treatment is 1165-1170 ℃, the pressure is 125-135 MPa, the time is 210-270 min, and introducing argon into the isostatic pressure heat treatment equipment after the isostatic pressure treatment to rapidly cool the Inconel718 alloy blank to room temperature;

s3, stress relief annealing treatment: placing the Inconel718 alloy blank subjected to isostatic pressure heat treatment in a high-temperature heating inner bore of a heat treatment furnace, and performing stress relief annealing under the protection of argon atmosphere, wherein the stress relief annealing temperature is 790-810 ℃, and the time is 20-40 min;

s4, solution treatment: after the stress relief annealing treatment operation is finished, keeping the protection of the argon atmosphere of the high-temperature heating inner chamber, raising the temperature of the heating inner chamber to perform solution treatment on the Inconel718 alloy blank subjected to the stress relief annealing treatment, wherein the solution treatment temperature is 940-960 ℃, the time is 20-40 min, and after the solution treatment, filling argon into a heat treatment furnace to be rapidly cooled to below 500 ℃;

s5, double-stage aging treatment: placing the Inconel718 alloy blank subjected to solution treatment in a high-temperature heating inner bore of a heat treatment furnace, performing two-stage aging treatment under the protection of argon atmosphere, wherein the temperature of the first-stage aging treatment is 750-770 ℃, the time is 470-490 min, the temperature of the second-stage aging treatment is 640-660 ℃, the time is 470-490 min, filling argon into the heat treatment furnace after the aging treatment, rapidly cooling to below 200 ℃, and discharging to finish the preparation of the high-strength high-plasticity Inconel718 alloy.

2. The SLM-based high-strength high-plasticity Inconel718 alloy preparation method according to claim 1, wherein the method comprises the following steps: the printing parameters of the step S1 of melting, forming and printing the Inconel718 alloy blank in the selected laser area are as follows: the printing power is 190W-210W, the layer height is 29 μm-31 μm, the scanning speed is 890 mm/s-910 mm/s, and the scanning distance is 0.98 mm-1.2 mm.

3. The method for preparing the SLM-based high-strength high-plasticity Inconel718 alloy according to claim 1 or 2, wherein the method comprises the following steps: the particle size of Inconel718 alloy powder used for selective laser melting molding in the step S1 is 45-60 mu m.

4. The SLM-based high-strength high-plasticity Inconel718 alloy preparation method according to claim 1, wherein the method comprises the following steps: the step S2 is carried out by isostatic pressing heat treatment at the temperature of not higher than 6.67 multiplied by 10 ^-2 Pa under vacuum.

5. The SLM-based high-strength high-plasticity Inconel718 alloy preparation method according to claim 1, wherein the method comprises the following steps: and the time of the hot isostatic pressing heat treatment in the step S2 is 235-245 min.

6. The SLM-based high-strength high-plasticity Inconel718 alloy preparation method according to claim 1, wherein the method comprises the following steps: the temperature of the stress-relief annealing treatment in the step S3 is 795-805 ℃, and the time is 25-35 min.

7. The SLM-based high-strength high-plasticity Inconel718 alloy preparation method according to claim 1, wherein the method comprises the following steps: the temperature of the solid solution treatment in the step S4 is 945-955 ℃, and the time is 25-35 min.

8. The method for preparing the SLM-based high-strength high-plasticity Inconel718 alloy according to claim 1 or 7, wherein the method comprises the following steps: in the step S4, after the stress relief annealing treatment operation is completed, the argon atmosphere protection of the high-temperature heating inner chamber is kept, and the temperature of the heating inner chamber is increased at the heating rate of 8-10 ℃/min to perform solution treatment on the Inconel718 alloy blank subjected to the stress relief annealing treatment.

9. The SLM-based high-strength high-plasticity Inconel718 alloy preparation method according to claim 1, wherein the method comprises the following steps: in the double-stage aging treatment of the step S5, the temperature of the first-stage aging treatment is 755-765 ℃, the time is 475 min-485 min, the temperature of the second-stage aging treatment is 645-655 ℃, and the time is 475 min-485 min.

10. The method for preparing the SLM-based high-strength high-plasticity Inconel718 alloy according to claim 1 or 9, wherein the method comprises the following steps: in the double-stage aging treatment of the step S5, after the first-stage aging treatment, the temperature of the heating inner chamber is controlled to be furnace-cooled to the temperature of the second-stage aging treatment at the cooling rate of 40-60 ℃/h.

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