Method for manufacturing nickel alloy having excellent high-temperature tensile properties, and nickel alloy manufactured using same

Abstract

The present invention relates to a method for manufacturing a nickel alloy having excellent high-temperature tensile properties, and a nickel alloy manufactured using same, and, more specifically, to a method for manufacturing a nickel alloy having excellent high-temperature tensile properties, and a nickel alloy manufactured using same, the method improving both tensile strength and ductility at a high temperature by exhibiting δ-phase precipitation strengthening through laser additive manufacturing and heat treatment.

Description

Method for manufacturing a nickel alloy having excellent high-temperature tensile properties and a nickel alloy manufactured according to the same

[0001] The present invention relates to a method for manufacturing a nickel alloy having excellent high-temperature tensile properties and a nickel alloy manufactured according to the same. More specifically, the invention relates to a method for manufacturing a nickel alloy having excellent high-temperature tensile properties that improves both tensile strength and ductility at high temperatures by exhibiting δ-phase precipitation strengthening through laser additive manufacturing and heat treatment, and a nickel alloy manufactured according to the same.

[0002]

[0003] As the aerospace industry advances, there is a growing need for materials that provide high stability and strength in high-temperature and extreme environments. Nickel alloys exhibit excellent mechanical properties at high temperatures and are attracting attention in high-tech fields such as the automotive, aerospace, and energy industries. However, nickel alloys manufactured by conventional casting methods form δ-grains at high temperatures, which leads to a problem of performance degradation.

[0004] Due to the aforementioned problems, there is a need to develop a method for manufacturing nickel alloys that exhibit excellent performance even at high temperatures.

[0005]

[0006] The objective of the present invention is to provide a method for manufacturing a nickel alloy having excellent high-temperature tensile properties and a nickel alloy manufactured according to the same in order to solve the above-mentioned problems.

[0007] In addition, the objective of the present invention is to provide a method for manufacturing a nickel alloy capable of improving both strength and ductility at high temperatures through δ-phase precipitation strengthening via laser powder bed fusion (LPBF) and heat treatment, and a nickel alloy manufactured according to this method.

[0008] The technical problems that the present invention aims to solve are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art from the description of the present invention.

[0009]

[0010] To achieve the above objective, the present invention aims to provide a method for manufacturing a nickel alloy having excellent high-temperature tensile properties, comprising: a first step of providing nickel alloy powder manufactured by a gas jet method; a second step of setting process variables for laser powder bed fusion (LPBF); a third step of supplying the nickel alloy powder; a fourth step of selectively irradiating a molding light source to melt the nickel alloy powder; a fifth step of forming a single layer while cooling and solidifying the molten nickel alloy powder; a sixth step of repeating steps 3 through 5 to form a layer by stacking until a three-dimensional mold of the nickel alloy material is completed; a seventh step of solution annealing the layer; and an eighth step of aging the annealed layer.

[0011] In the present invention, the second step of setting process parameters for the laser powder bed melting comprises a laser power of 270 to 300 W, a scan speed of 960 to 1110 mm / s, a hatching distance of 100 to 120 μm, a layer thickness of 30 to 50 μm, and an energy density of 60.1 to 68.5 × 10⁻⁶. 9 J / m -3 It is characterized by setting process variables as follows.

[0012] In the present invention, the seventh step of solution annealing comprises: a step of solution annealing the laminate at 970 to 990 ℃ for 50 to 70 minutes; and a step of water-cooling the solution-annealed laminate.

[0013] In the present invention, the eighth step of the aging treatment comprises: a step of heat-treating the annealed laminate at 700 to 740 ℃ for 7 to 9 hours; and a step of cooling the heat-treated laminate to 600 to 640 ℃ within 50 to 70 minutes and maintaining it at the cooling temperature for 7 to 9 hours.

[0014] In the present invention, the nickel alloy powder is characterized by comprising, based on 100 parts by weight of the nickel alloy powder, 50 to 55 parts by weight of nickel, 17 to 21 parts by weight of chromium, 2.8 to 3.3 parts by weight of molybdenum, 4.75 to 5.5 parts by weight of niobium, 0.01 to 0.08 parts by weight of carbon, 0.1 to 0.35 parts by weight of manganese, 0.1 to 0.35 parts by weight of silicon, 0.001 to 0.015 parts by weight of sulfur, 0.01 to 0.30 parts by weight of copper, 0.2 to 0.8 parts by weight of aluminum, 0.65 to 1.15 parts by weight of titanium, 0.01 to 0.06 parts by weight of boron, and 12.095 to 24.369 parts by weight of iron.

[0015] The present invention aims to provide a nickel alloy having excellent high-temperature tensile properties, manufactured according to the above manufacturing method and having a δ phase precipitated therein.

[0016]

[0017] By means of the solution to the above problem, the present invention can provide a method for manufacturing a nickel alloy having excellent high-temperature tensile properties and a nickel alloy manufactured according to the same.

[0018] In addition, the present invention can provide a method for manufacturing a nickel alloy capable of improving both strength and ductility at high temperatures through δ-phase precipitation strengthening via laser powder bed fusion (LPBF) and heat treatment, and a nickel alloy manufactured according to the same.

[0019] In addition, the present invention can provide a method for manufacturing a nickel alloy capable of producing parts of complex shapes through an additive manufacturing method, and a nickel alloy manufactured according to the same.

[0020] The effects of the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art from the description in the claims.

[0021]

[0022] FIG. 1 is a diagram showing the manufacturing process of a nickel alloy having excellent high-temperature tensile properties according to the present invention.

[0023] FIG. 2 is a diagram showing the measurement results of elongation and tensile strength at room temperature and high temperature of an example and a comparative example according to the present invention.

[0024]

[0025] The terms used in this specification have been selected based on currently widely used general terms whenever possible, taking into account their functions in the present invention; however, these terms may vary depending on the intent of those skilled in the art, case law, the emergence of new technologies, etc. Additionally, in specific cases, terms have been arbitrarily selected by the applicant, and in such cases, their meanings will be described in detail in the corresponding description of the invention. Therefore, the terms used in this invention should be defined not merely by their names, but based on their meanings and the overall content of the invention.

[0026] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0027] Numerical ranges include the values ​​defined in the above ranges. All maximum numerical limits given throughout this specification include all lower numerical limits as clearly written. All minimum numerical limits given throughout this specification include all higher numerical limits as clearly written. All numerical limits given throughout this specification will include all better numerical ranges within a wider numerical range, as clearly written.

[0028]

[0029] Method for manufacturing a nickel alloy having excellent high-temperature tensile properties and a nickel alloy manufactured according to the same

[0030] The present invention relates to a method for manufacturing a nickel alloy having excellent high-temperature tensile properties.

[0031] The present invention relates to a method for manufacturing a nickel alloy having excellent high-temperature tensile properties, comprising: a first step of providing nickel alloy powder manufactured by a gas jet method; a second step of setting process variables for laser powder bed fusion (LPBF); a third step of supplying the nickel alloy powder; a fourth step of selectively irradiating a molding light source to melt the nickel alloy powder; a fifth step of forming a single layer while cooling and solidifying the molten nickel alloy powder; a sixth step of repeating steps 3 through 5 to form a layer by stacking until a three-dimensional molded nickel alloy material is completed; a seventh step of solution annealing the layer; and an eighth step of aging the annealed layer.

[0032] The above manufacturing method may be a method for producing a nickel alloy that exhibits excellent surface properties by forming a microstructure through laser powder bed fusion (LPBF) and exhibits excellent mechanical stability by not containing internal pores. Additionally, the above manufacturing method may be a method for producing a nickel alloy that exhibits high tensile strength and ductility even at high temperatures through δ-phase precipitation strengthening in the microstructure via heat treatment.

[0033] In the present invention, the second step of setting process parameters for the laser powder bed melting comprises a laser power of 270 to 300 W, a scan speed of 960 to 1110 mm / s, a hatching distance of 100 to 120 μm, a layer thickness of 30 to 50 μm, and an energy density of 60.1 to 68.5 × 10⁻⁶. 9 J / m -3 It may be possible to set process variables as such.

[0034] If the laser power is less than 270 W, the energy density is low and the powder cannot be completely melted, which may result in a decrease in tensile properties due to unmelted powder; if it exceeds 300 W, the energy density is too high and may cause the additive manufacturing structure to be physically deformed due to the influence of unreleased thermal stress. Therefore, it is desirable to perform the process under the above conditions.

[0035] If the above scan speed is less than 960 mm / s, a problem may arise where the layer creation time is long, and if it exceeds 1110 mm / s, the layered alloy may be physically deformed due to the creation of micropores and unmolten powder inside, and a problem may arise where the tensile strength is reduced, so it is desirable to perform under the above conditions.

[0036] If the above hatching interval is less than 100 μm, a problem may occur in which deformation occurs due to thermal stress that is not relieved due to excessive energy load in the overlapping section of the laser beam, and if it exceeds 120 μm, a problem may occur in which micropores are created in the unmelted space and tensile properties are degraded, so it is desirable to perform under the above conditions.

[0037] If the layer thickness is less than 30 μm, the lamination time is long and deformation of the laminated alloy may occur, and if the layer thickness exceeds 50 μm, unmelted layers may occur, and cracks may form in the unbonded layers, causing separation; therefore, it is desirable to perform the process under the above conditions.

[0038] In the present invention, the seventh step of solution annealing comprises: a step of solution annealing the laminate at 970 to 990 ℃ for 50 to 70 minutes; and a step of water-cooling the solution-annealed laminate.

[0039] In the present invention, the eighth step of the aging treatment comprises: a step of heat-treating the annealed laminate at 700 to 740 ℃ for 7 to 9 hours; and a step of cooling the heat-treated laminate to 600 to 640 ℃ within 50 to 70 minutes and maintaining it at the cooling temperature for 7 to 9 hours. The rapid cooling rate of the heat treatment step may accelerate Nb splitting at grain boundaries, thereby causing the formation of a δ phase. Due to the mismatch between the formed δ phase and the γ matrix and the brittleness of the δ phase, the dislocations are concentrated at the boundary between the δ phase and the γ matrix, and the locking of dislocations by the δ phase may cause stress concentration, thereby hindering dislocation movement and increasing strength at high temperatures.

[0040] In the present invention, the nickel alloy powder is characterized by comprising, based on 100 parts by weight of the nickel alloy powder, 50 to 55 parts by weight of nickel, 17 to 21 parts by weight of chromium, 2.8 to 3.3 parts by weight of molybdenum, 4.75 to 5.5 parts by weight of niobium, 0.01 to 0.08 parts by weight of carbon, 0.1 to 0.35 parts by weight of manganese, 0.1 to 0.35 parts by weight of silicon, 0.001 to 0.015 parts by weight of sulfur, 0.01 to 0.30 parts by weight of copper, 0.2 to 0.8 parts by weight of aluminum, 0.65 to 1.15 parts by weight of titanium, 0.01 to 0.06 parts by weight of boron, and 12.095 to 24.369 parts by weight of iron.

[0041] The nickel alloy manufactured from the above nickel alloy powder may exhibit high heat resistance, excellent processability, and long-term structural stability. In addition, it may have high tensile strength, fatigue strength, and creep fracture strength, as well as excellent oxidation resistance and corrosion resistance.

[0042] The present invention relates to a nickel alloy having excellent high-temperature tensile properties, manufactured according to the above manufacturing method and having a δ phase precipitated therein. The nickel alloy exhibits high tensile strength and elongation at room temperature and high temperature, and in particular, the tensile strength may be at the highest level, and may have high high-temperature stability and design flexibility. In addition, the nickel alloy may exhibit high productivity and be capable of being manufactured into complex shapes.

[0043]

[0044] Examples

[0045] The embodiments of the present invention are described in detail below, but it is obvious that the present invention is not limited by the following embodiments.

[0046] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described in detail below. However, the present invention is not limited to the embodiments disclosed below but can be implemented in various different forms. The embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims.

[0047]

[0048] <Example 1> Nickel alloy manufactured by performing laser additive manufacturing and heat treatment

[0049] Nickel alloy powder with a composition of 100 wt% as shown in [Table 1] below was prepared using a gas injection method.

[0050] NiCrMoNbCMnSiSCuAlTiBFe55203.05.00.080.350.350.010.300.51.00.06Bal.

[0051]

[0052] A nickel alloy was manufactured by additively fabricating the nickel alloy powder prepared as described above into rod shapes with a diameter of 10 mm in the horizontal (HD) and vertical (VD) directions using a laser powder bed melting method. In this additive manufacturing process, to minimize directional particles, the layer-by-layer procedure was performed continuously in a 67° rotational scan direction, with a laser output of 285 W, a scan speed of 960 mm / s, a hatching spacing of 1100 μm, a layer thickness of 40 μm, and an energy density of 67.5 × 10⁻⁶. 9 J / m -3 A nickel alloy was manufactured by setting it to [this] and stacking it.

[0053] The nickel alloy prepared above was subjected to solution annealing at 980°C for 1 hour, and then water-cooled in a furnace to room temperature. Subsequently, the nickel alloy was prepared by heat-treating at 720°C for 8 hours, cooling in the furnace to 620°C within 1 hour, and maintaining the temperature for 8 hours.

[0054]

[0055] <Comparative Example 1> Nickel alloy not subjected to heat treatment

[0056] A nickel alloy was prepared in the same manner as in Example 1 above, except that no heat treatment was performed.

[0057]

[0058] <Experimental Example 1> Measurement of Elongation and Tensile Strength at Room and High Temperatures

[0059] The elongation and tensile strength of the nickel alloys prepared in Example 1 and Comparison 1 at 25°C and 650°C were measured, and the results are shown in Figure 2.

[0060] As shown in Fig. 2, when a load is applied to the nickel alloy of Comparative Example 1 at 650°C, slip dislocations are accommodated at the γ′′ / δ interface, causing the δ phase to bend. Consequently, the local disorder transition of the δ phase is attributed to the combination of elastic modulus mismatch and stacking faults. Accordingly, the high density of bent δ particles hinders the movement of trailing dislocations, inducing non-uniform deformation at 650°C. This results in low elongation and tensile strength, as well as low yield strength and low strain hardening rate during tensile deformation at 650°C.

[0061] On the other hand, in the nickel alloy of Example 1 above, due to the mismatch between the δ phase formed at the grain boundary and the γ matrix and the brittleness of the δ phase, the dislocations are concentrated at the boundary between the δ phase and the γ matrix, and the fixation of dislocations by the δ phase causes stress concentration, which hinders dislocation movement and increases strength at high temperatures, exhibiting excellent elongation and tensile strength at 650 ℃, and also exhibiting excellent elongation and tensile strength at 25 ℃ through the compositional characteristics of the nickel alloy used in Example 1 and the formation of a microstructure through laser additive manufacturing.

[0062] Through the above results, it was confirmed that the nickel alloy manufactured according to the method for manufacturing a nickel alloy having excellent high-temperature tensile properties according to the present invention exhibits excellent tensile properties, including elongation and tensile strength, at high temperatures.

Claims

1. A first step of providing nickel alloy powder manufactured by a gas atomization method; Step 2 for setting process parameters for laser powder bed fusion (LPBF); A third step of supplying the above nickel alloy powder; A fourth step of selectively irradiating a molding light source to melt the nickel alloy powder; A fifth step of forming a single layer while cooling and solidifying the molten nickel alloy powder; Step 6, forming a laminate by repeating Steps 3 through 5 until the three-dimensional mold of the nickel alloy material is completed; Step 7, solution annealing the above laminate; and A method for manufacturing a nickel alloy having excellent high-temperature tensile properties, comprising: an eighth step of aging the annealed laminate.

2. In Paragraph 1, The second step of setting process variables for the laser powder bed melting described above is, Laser power 270 to 300 W, scan speed 960 to 1110 mm / s, hatching distance 100 to 120 µm, layer thickness 30 to 50 µm, and energy density 60.1 to 68.5 × 10⁻⁶ 9 J / m -3 A method for manufacturing a nickel alloy having excellent high-temperature tensile properties, characterized by setting process variables as follows.

3. In Paragraph 1, The seventh step of annealing the above solution is, A step of solution annealing the above laminate at 970 to 990 ℃ for 50 to 70 minutes; and A method for manufacturing a nickel alloy having excellent high-temperature tensile properties, characterized by including the step of water-cooling the solution-annealed laminate.

4. In Paragraph 1, The eighth step of the above-mentioned statute of limitations processing is, A step of heat-treating the annealed laminate at 700 to 740 ℃ for 7 to 9 hours; and A method for manufacturing a nickel alloy having excellent high-temperature tensile properties, characterized by including the step of cooling the heat-treated laminate to 600 to 640 ℃ within 50 to 70 minutes and maintaining it at the cooling temperature for 7 to 9 hours.

5. In Paragraph 1, The above nickel alloy powder is, A method for manufacturing a nickel alloy having excellent high-temperature tensile properties, characterized by comprising, based on 100 parts by weight of the nickel alloy powder, 50 to 55 parts by weight of nickel, 17 to 21 parts by weight of chromium, 2.8 to 3.3 parts by weight of molybdenum, 4.75 to 5.5 parts by weight of niobium, 0.01 to 0.08 parts by weight of carbon, 0.1 to 0.35 parts by weight of manganese, 0.1 to 0.35 parts by weight of silicon, 0.001 to 0.015 parts by weight of sulfur, 0.01 to 0.30 parts by weight of copper, 0.2 to 0.8 parts by weight of aluminum, 0.65 to 1.15 parts by weight of titanium, 0.01 to 0.06 parts by weight of boron, and 12.095 to 24.369 parts by weight of iron.

6. A nickel alloy having excellent high-temperature tensile properties, manufactured according to the manufacturing method of claim 1 and having a δ phase precipitated.

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