Melt forming and hot isostatic pressing preparation method of high-density GH4099 alloy

Abstract

The invention provides a melt forming and hot isostatic pressing preparation method of a high-density GH4099 alloy, and relates to the technical field of additive manufacturing. The method comprises the steps that firstly, GH4099 nickel-based superalloy powder is screened, obtained powder with the specific particle size is dried, secondly, the dried GH4099 nickel-based superalloy powder with the specific particle size is placed in an equipment powder bin, and the GH4099 nickel-based superalloy powder is subjected to fusion forming through a laser powder bed fusion technology; and finally, the formed GH4099 nickel-based high-temperature alloy is subjected to hot isostatic pressing treatment. According to the GH4099 nickel-based high-temperature alloy product prepared by the method disclosed by the invention, the defect rate and the generation of cracks are reduced, and the GH4099 nickel-based high-temperature alloy product has extremely high density; and through hot isostatic pressing treatment, the density is further improved, and the technical problems that in the prior art, after GH4099 nickel-based superalloy is subjected to additive manufacturing forming, cracking is prone to occurring, the number of hole defects is large, and the density is low are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and in particular to a preparation method of high-density GH4099 alloy by melt forming and hot isostatic pressing. Background Art

[0002] GH4099 nickel-based high-temperature alloy is a precipitation-strengthened material with Ni and Cr as the matrix, W, Mo, Co elements for solid solution strengthening, γ' (Al, Ti) phase for aging strengthening, B and C element purification and grain boundary strengthening. It has excellent corrosion resistance, good machinability and weldability. Its main operating temperature is 700-1000℃, and it can be used in aircraft engine combustion chambers, baffles, stiffeners, aircraft fixtures and guide blades and other parts. In the traditional subtractive manufacturing process, the processing difficulty of GH4099 high-temperature alloy is low, the material consumption is high, and the cost of its production is high.

[0003] Laser Powder Bed Fusion (LPBF) technology heats the powder bed by scanning with a laser heat source, selectively melting and bonding loose powders, and can achieve near-net-shape forming of parts with complex shapes. It has the advantages of simple manufacturing process, short manufacturing cycle, material saving, and the ability to form complex internal structures. This technology has been widely used in aerospace, automotive and other fields.

[0004] However, in the technical application of GH4099 nickel-based high-temperature alloy with high strength and high alloying characteristics, due to the non-equilibrium solidification behavior and stress during the forming process, defects such as cracks and holes are very likely to occur during the forming process.

[0005] Hot isostatic pressing technology can usually achieve the effect of bridging cracks and defects by applying a certain amount of pressure to metal parts at high temperatures. However, low density and large defect size will weaken its processing effect. Therefore, the low density and low confidence of GH4099 nickel-based high-temperature alloy products formed by laser powder bed fusion have greatly restricted the application of this technology in the preparation of nickel-based high-temperature alloy parts.

[0006] For example, Chinese patent CN112589115A realizes the laser selective melting forming process of GH4099 nickel-based high-temperature alloy. The comprehensive mechanical properties of the formed products have reached the level of forgings, but the range of process parameters is large, and there is no clear description and characterization of defects such as density and cracks, making it difficult to promote and apply industrial production; and the prepared products have low precision and cannot prepare products with complex shapes.

[0007] Chinese patent CN117047125A controls the forming parameters by laser selective melting technology to manufacture GH4099 nickel-based high-temperature alloy and performs solution heat treatment and aging heat treatment, thereby suppressing cracks in the formed GH4099 nickel-based high-temperature alloy products and improving the room temperature mechanical properties. However, the number of pore defects in the GH4099 nickel-based high-temperature alloy formed by this method is high and the density is low. The same is true for Chinese patent CN113059189A.

[0008] Chinese patent CN111604448A discloses a forging method for a high-temperature alloy GH4099. The method improves the density of the product by forging. However, the homogenization treatment time is as long as 48 hours, the forging process is long, time-consuming, and consumes a lot of heat. Although it can improve the distribution of carbides and grains of the steel and eliminate the organizational defects of low-magnification coarse grains and high-magnification mixed grains to a certain extent, it is obvious that the shape of the prepared material is greatly limited, and the main technical defects in the forging process include cracks and grain boundary weakening. Summary of the invention

[0009] In order to solve the technical problems caused by the traditional high-temperature alloy GH4099 preparation method, such as a high number of hole defects, a high crack occurrence rate, long working hours, high heat consumption, high cost, low efficiency, low precision, inability to prepare products with complex shapes, low density, and low confidence, the present invention proposes a preparation method for melt forming and hot isostatic pressing of a high-density GH4099 alloy that can solve the above problems. The technical solution is as follows:

[0010] A preparation method of high-density GH4099 alloy by melt forming and hot isostatic pressing, the preparation method of melt forming and hot isostatic pressing comprises the following steps:

[0011] S1. Pretreatment of GH4099 alloy powder: sieving GH4099 nickel-based high-temperature alloy powder to obtain powder with a specific particle size; drying the obtained powder with a specific particle size to obtain powder with a specific particle size after drying;

[0012] S2, laser powder bed melting forming: the powder with a specific particle size after drying in S1 is placed in the powder bin of the equipment, and the powder with a specific particle size after drying placed on the substrate is melted and formed by laser powder bed melting technology to obtain a preliminarily formed alloy material;

[0013] S3, hot isostatic pressing treatment: After S2 is melt-formed, hot isostatic pressing treatment is performed to obtain a high-density GH4099 alloy.

[0014] Optionally, the particle size of the GH4099 nickel-based high-temperature alloy powder in S1 is 10-200 μm, the screening particle size of the powder with a specific particle size is 10-53 μm, the drying temperature is 110-120° C., and the drying time is 2-5 h.

[0015] Optionally, the melt forming process in S2 requires the substrate to be preheated, and the heating rate of the substrate preheating is 100-200°C / h and the temperature is 50-150°C.

[0016] Optionally, the material of the substrate formed by melting in S2 is 316L stainless steel or 45 steel.

[0017] Optionally, when the powder of a specific particle size after drying is melted and formed by laser powder bed melting technology in S2, the laser power used is 270-300W, the laser spot diameter is 70μm, the scanning speed is 900-1200mm / s, the scanning interval is 90-120μm, and the layer thickness is 0.3-0.6μm.

[0018] Optionally, in S2, when the bottom area of ​​the prepared substrate is 5×5 mm-100×100 mm, the single-layer forming height is 30-60 μm, and the total forming height is 10-100 mm.

[0019] Optionally, in S2, when the bottom area of ​​the forming substrate is 30×40 mm, the single-layer forming height is 0.04 mm, and the total forming height is 80 mm, the laser power is 300 W, the laser spot diameter is 70 μm, the scanning speed is 1000 mm / s, and the scanning spacing is 0.11 mm.

[0020] Optionally, the heating rate of the hot isostatic pressing treatment in S3 is 250-300°C / h, the temperature is 1150-1200°C, the pressure is 120-180MPa, the holding time is 2h, and the cooling method is furnace cooling.

[0021] Optionally, in S3, the furnace cooling is performed at a cooling rate of less than 5°C / min above 900°C and at a cooling rate of less than 1°C / min below 900°C.

[0022] Optionally, the porosity of the high-density GH4099 alloy in S3 is 0%, the tensile strength is 1150-1250MPa, the yield strength is 700-980MPa, the yield strength ratio is 0.60-0.78, and the elongation at break is 15-25%; the high-temperature tensile strength at 700°C is 950-1000MPa, the yield strength is 620-800MPa, the yield strength ratio is 0.72-0.80, and the elongation at break is 6-10%; the high-temperature tensile strength at 800°C is 700-730MPa, the yield strength is 610-700MPa, the yield strength ratio is 0.87-0.95, and the elongation at break is 9-15%; the high-temperature tensile strength at 900°C is 475-500MPa, the yield strength is 400-420MPa, the yield strength ratio is 0.80-0.84, and the elongation at break is 15-20%.

[0023] Compared with the prior art, the above technical solution has at least the following beneficial effects:

[0024] The above scheme, the present invention proposes a preparation method of melt forming and hot isostatic pressing of high-density GH4099 alloy, which can solve the technical problems caused by the traditional high-temperature alloy GH4099 preparation method, such as a high number of hole defects, a high crack occurrence rate, long working hours, high heat consumption, high cost, low efficiency, low precision, inability to prepare products with complex shapes, low density, and low confidence.

[0025] The present invention screens the particle size of the powder and controls the water content, and then forms the GH4099 nickel-based high-temperature alloy through a laser powder bed melting technology, so that the prepared product is free of cracks and the defect rate is greatly reduced.

[0026] The present invention performs hot isostatic pressing on the formed product to make the prepared product fully dense, thereby greatly improving the size, shape accuracy and product confidence of the additively manufactured GH4099 nickel-based high-temperature alloy product.

[0027] In summary, compared with other traditional methods, the method of the present invention uses laser powder bed melting technology to form GH4099 nickel-based high-temperature alloy. The prepared product has no cracks and greatly reduces the defect rate. After the formed product is subjected to hot isostatic pressing treatment, the prepared product can achieve full density, which greatly improves the confidence of additively manufactured GH4099 nickel-based high-temperature alloy products. The method is simple and easy to operate, has high production flexibility, low cost, short process and high efficiency, and provides a high-quality forming and manufacturing method for the hot end components of aerospace engines and gas turbines with complex structures, which is conducive to large-scale industrial production and promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 This is a metallographic test diagram of a product prepared by melt forming of a high-density GH4099 alloy in Example 1 of the present invention;

[0030] Figure 2 This is a micro-CT three-dimensional test image of a product prepared by melt forming of a high-density GH4099 alloy in Example 1 of the present invention;

[0031] Figure 3This is a micro-CT three-dimensional test image of a product prepared by melt forming and hot isostatic pressing of a high-density GH4099 alloy in Example 1 of the present invention;

[0032] Figure 4 This is a metallographic test diagram of a product prepared by melt forming of a high-density GH4099 alloy in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0033] The technical solution of the present invention is described below in conjunction with the accompanying drawings.

[0034] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "example" in the present invention should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of the word "example" is intended to present the concept in a specific way. In addition, in the embodiments of the present invention, the meaning expressed by "and / or" can be both, or it can be either of the two.

[0035] In the embodiments of the present invention, "image" and "picture" may sometimes be used interchangeably. It should be noted that when the distinction between them is not emphasized, the meanings they intend to express are consistent.

[0036] In the embodiments of the present invention, sometimes a subscript such as W1 may be written as a non-subscript such as W1. When the difference is not emphasized, the meanings to be expressed are consistent.

[0037] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0038] A preparation method of high-density GH4099 alloy by melt forming and hot isostatic pressing, the preparation method of melt forming and hot isostatic pressing comprises the following steps:

[0039] S1. Pretreatment of GH4099 alloy powder: sieving GH4099 nickel-based high-temperature alloy powder to obtain powder with a specific particle size; drying the obtained powder with a specific particle size to obtain powder with a specific particle size after drying;

[0040] S2, laser powder bed melting forming: the powder with a specific particle size after drying in S1 is placed in the powder bin of the equipment, and the powder with a specific particle size after drying placed on the substrate is melted and formed by laser powder bed melting technology to obtain a preliminarily formed alloy material;

[0041] S3, hot isostatic pressing treatment: After S2 is melt-formed, hot isostatic pressing treatment is performed to obtain a high-density GH4099 alloy.

[0042] In particular, the particle size of the GH4099 nickel-based high-temperature alloy powder in S1 is 10-200 μm, the screening particle size of the powder with a specific particle size is 10-53 μm, the drying temperature is 110-120° C., and the drying time is 2-5 h.

[0043] In particular, the melt forming process in S2 requires the substrate to be preheated, and the heating rate of the substrate preheating is 100-200°C / h and the temperature is 50-150°C.

[0044] In particular, the material of the substrate formed by melt forming in S2 is 316L stainless steel or 45 steel.

[0045] In particular, when the powder of a specific particle size after drying is melted and formed by laser powder bed melting technology in S2, the laser power used is 270-300W, the laser spot diameter is 70μm, the scanning speed is 900-1200mm / s, the scanning interval is 90-120μm, and the layer thickness is 0.3-0.6μm.

[0046] In particular, in S2, when the bottom area of ​​the prepared substrate is 5×5 mm-100×100 mm, the single-layer forming height is 30-60 μm, and the total forming height is 10-100 mm.

[0047] In particular, in S2, when the bottom area of ​​the forming substrate is 30×40 mm, the single-layer forming height is 0.04 mm, and the total forming height is 80 mm, the laser power is 300 W, the laser spot diameter is 70 μm, the scanning speed is 1000 mm / s, and the scanning spacing is 0.11 mm.

[0048] In particular, the heating rate of the hot isostatic pressing treatment in S3 is 250-300°C / h, the temperature is 1150-1200°C, the pressure is 120-180MPa, the holding time is 2h, and the cooling method is furnace cooling.

[0049] In particular, in S3, the cooling rate of the furnace is less than 5°C / min above 900°C, and the cooling rate is less than 1°C / min below 900°C.

[0050] In particular, the porosity of the S3 medium-high density GH4099 alloy is 0%, the tensile strength is 1150-1250MPa, the yield strength is 700-980MPa, the yield strength ratio is 0.60-0.78, and the elongation at break is 15-25%; the high-temperature tensile strength at 700°C is 950-1000MPa, the yield strength is 620-800MPa, the yield strength ratio is 0.72-0.80, and the elongation at break is 6-10%; the high-temperature tensile strength at 800°C is 700-730MPa, the yield strength is 610-700MPa, the yield strength ratio is 0.87-0.95, and the elongation at break is 9-15%; the high-temperature tensile strength at 900°C is 475-500MPa, the yield strength is 400-420MPa, the yield strength ratio is 0.80-0.84, and the elongation at break is 15-20%.

[0051] Example 1

[0052] A preparation method of high-density GH4099 alloy by melt forming and hot isostatic pressing, the preparation method of melt forming and hot isostatic pressing comprises the following steps:

[0053] S1. Pretreatment of GH4099 alloy powder: sieving GH4099 nickel-based high-temperature alloy powder with a particle size of 10-200 μm to obtain powder with a specific particle size of 10-53 μm; drying the obtained powder with a specific particle size at a drying temperature of 110° C. for 5 hours to obtain a powder with a specific particle size after drying;

[0054] S2, laser powder bed melting forming: the powder of specific particle size after drying in S1 is placed in the powder bin of the equipment, and the powder of specific particle size after drying placed on the substrate is melted and formed by laser powder bed melting technology. When the bottom area of ​​the forming substrate is 15×15mm, the single-layer forming height is 40μm, and the total forming height is 15mm, the laser power is 270W, the laser spot diameter is 70μm, the scanning speed is 900mm / s, and the scanning interval is 110μm, the preliminary formed alloy material is obtained, and the metallographic test results are as follows: Figure 1 As shown in Figure 2, the porosity was determined to be 0.003% by micro-CT. Figure 2 As shown; wherein: the material of the melt-formed substrate is 316L stainless steel, the melt-formed process requires the substrate to be preheated, the substrate preheating rate is 100°C / h, the temperature is 150°C, the first layer is firmly adhered to the substrate after cooling during the forming process, and after the final deposition is completed, the formed product is cut off from the substrate by wire cutting;

[0055] S3, hot isostatic pressing treatment: After S2 is melt-formed, hot isostatic pressing treatment is performed, with a heating rate of 300℃ / h, a temperature of 1200℃, a pressure of 120MPa, a holding time of 2h, and a cooling method of furnace cooling. The cooling rate is less than 5℃ / min above 900℃ and less than 1℃ / min below 900℃, and a high-density GH4099 alloy is obtained; the micro-CT results are as follows Figure 3 As shown in the figure, all defects of GH4099 nickel-based superalloy products formed by laser powder bed melting have disappeared, further improving the density of GH4099 nickel-based superalloy.

[0056] The porosity of the high-density GH4099 alloy prepared in this embodiment is 0%, the tensile strength is 1250MPa, the yield strength is 980MPa, the yield ratio is 0.78, and the elongation at break is 25%; the high-temperature tensile strength at 700°C is 1000MPa, the yield strength is 800MPa, the yield ratio is 0.80, and the elongation at break is 10%; the high-temperature tensile strength at 800°C is 730MPa, the yield strength is 700MPa, the yield ratio is 0.95, and the elongation at break is 15%; the high-temperature tensile strength at 900°C is 500MPa, the yield strength is 420MPa, the yield ratio is 0.84, and the elongation at break is 20%.

[0057] Comparative Example 1

[0058] A preparation method of high-density GH4099 alloy by melt forming and hot isostatic pressing, the preparation method of melt forming and hot isostatic pressing comprises the following steps:

[0059] S1. Pretreatment of GH4099 alloy powder: sieving GH4099 nickel-based high-temperature alloy powder with a particle size of 10-200 μm to obtain powder with a specific particle size of 10-53 μm; drying the obtained powder with a specific particle size at a drying temperature of 110° C. for 5 hours to obtain a powder with a specific particle size after drying;

[0060] S2. Laser powder bed melting: Place the powder of a specific particle size after drying in S1 in the powder bin of the equipment, and use the laser powder bed melting technology to melt the powder of a specific particle size placed on the substrate after drying. When the bottom area of ​​the forming substrate is 15×15mm, the single-layer forming height is 0.6μm, and the total forming height is 15mm, the laser power is 300W, the laser spot diameter is 70μm, the scanning speed is 1200mm / s, and the scanning interval is 120μm to obtain the alloy material. Figure 4 The metallographic test results of the product formed by this printing parameter show that the GH4099 nickel-based high-temperature alloy formed by this forming parameter still has extremely high density.

[0061] The porosity of the high-density GH4099 alloy prepared in this comparative example is 0.010%, the tensile strength is 950MPa, the yield strength is 710MPa, the yield ratio is 0.75, and the elongation at break is 38%; the high-temperature tensile strength at 700°C is 830MPa, the yield strength is 520MPa, the yield ratio is 0.62, and the elongation at break is 10%; the high-temperature tensile strength at 800°C is 650MPa, the yield strength is 510MPa, the yield ratio is 0.78, and the elongation at break is 13%; the high-temperature tensile strength at 900°C is 397MPa, the yield strength is 368MPa, the yield ratio is 0.92, and the elongation at break is 40%.

[0062] Compared with Comparative Example 1, Example 1 has the following technical advantages:

[0063] The forming parameters in Comparative Example 1S2 are the limit forming parameters in Example 1, and the porosity of the formed alloy material is still maintained in the range of 0.003-0.010, indicating that the melting forming parameter range of the high-density GH4099 alloy described in the present invention can effectively control the generation of defects during the forming process.

[0064] Comparative Example 1 does not use S3 in Example 1, and the porosity cannot be reduced compared to Example 1, which also leads to a significant decrease in the tensile strength, yield strength and elongation after fracture of the final formed alloy material at room temperature, 700°C, 800°C and 900°C, thereby reducing the mechanical properties of the formed alloy parts.

[0065] Example 2

[0066] A preparation method of high-density GH4099 alloy by melt forming and hot isostatic pressing, the preparation method of melt forming and hot isostatic pressing comprises the following steps:

[0067] S1. Pretreatment of GH4099 alloy powder: sieving GH4099 nickel-based high-temperature alloy powder with a particle size of 10-200 μm to obtain powder with a specific particle size of 10-53 μm; drying the obtained powder with a specific particle size at a drying temperature of 110° C. for 5 hours to obtain a powder with a specific particle size after drying;

[0068] S2, laser powder bed melting forming: the powder of specific particle size after drying in S1 is placed in the powder bin of the equipment, and the powder of specific particle size after drying placed on the substrate is melted and formed by laser powder bed melting technology. When the bottom area of ​​the forming substrate is 30×40mm, the single-layer forming height is 40μm, and the total forming height is 80mm, the laser power is 270W, the laser spot diameter is 70μm, the scanning speed is 900mm / s, and the scanning interval is 110μm, a preliminary formed alloy material is obtained; wherein: the material of the melt-formed substrate is 45# steel, and the melt-forming process requires the substrate to be preheated. The heating rate of the substrate preheating is 200℃ / h, and the temperature is 50℃. During the forming process, the first layer is cooled and firmly adhered to the substrate. After the final deposition is completed, the formed product is cut off from the substrate by wire cutting;

[0069] S3, hot isostatic pressing treatment: After S2 is melt-formed, hot isostatic pressing treatment is performed, with a heating rate of 300℃ / h, a temperature of 1200℃, a pressure of 180MPa, a holding time of 2h, and a cooling method of furnace cooling. The cooling rate is less than 5℃ / min above 900℃ and less than 1℃ / min below 900℃, and a high-density GH4099 alloy is obtained; the micro-CT results are as follows Figure 3 As shown in the figure, all defects of GH4099 nickel-based superalloy products formed by laser powder bed melting have disappeared, further improving the density of GH4099 nickel-based superalloy.

[0070] The porosity of the high-density GH4099 alloy prepared in this embodiment is 0%, 1180MPa, the yield strength is 760MPa, the yield strength ratio is 0.64, and the elongation at break is 17%; the high-temperature tensile strength at 700°C is 960MPa, the yield strength is 710MPa, the yield strength ratio is 0.74, and the elongation at break is 8%; the high-temperature tensile strength at 800°C is 710MPa, the yield strength is 640MPa, the yield strength ratio is 0.90, and the elongation at break is 10%; the high-temperature tensile strength at 900°C is 490MPa, the yield strength is 405MPa, the yield strength ratio is 0.83, and the elongation at break is 17%.

[0071] Example 3

[0072] A preparation method of high-density GH4099 alloy by melt forming and hot isostatic pressing, the preparation method of melt forming and hot isostatic pressing comprises the following steps:

[0073] S1. Pretreatment of GH4099 alloy powder: sieving GH4099 nickel-based high-temperature alloy powder with a particle size of 10-200 μm to obtain powder with a specific particle size of 10-53 μm; drying the obtained powder with a specific particle size at a drying temperature of 120° C. for a drying time of 2 h to obtain a powder with a specific particle size after drying;

[0074] S2, laser powder bed melting forming: the powder of specific particle size after drying in S1 is placed in the powder bin of the equipment, and the powder of specific particle size after drying placed on the substrate is melted and formed by laser powder bed melting technology. When the bottom area of ​​the forming substrate is 5×5mm, the single-layer forming height is 0.03mm, and the total forming height is 10mm, the laser power is 285W, the laser spot diameter is 70μm, the scanning speed is 1200mm / s, and the scanning interval is 0.09mm, a preliminary formed alloy material is obtained; wherein: the material of the melt-formed substrate is 316L stainless steel, and the melt-forming process requires the substrate to be preheated, and the preheating rate of the substrate is 100℃ / h, and the temperature is 100℃;

[0075] S3. Hot isostatic pressing: After S2 is melt-formed, hot isostatic pressing is performed with a heating rate of 300°C / h, a temperature of 1150°C, a pressure of 160MPa, a holding time of 2h, and a furnace cooling method. The furnace cooling rate is less than 5°C / min above 900°C and less than 1°C / min below 900°C to obtain a high-density GH4099 alloy.

[0076] The porosity of the high-density GH4099 alloy prepared in this embodiment is 0%, 1200MPa, the yield strength is 850MPa, the yield strength ratio is 0.71, and the elongation at break is 21%; the tensile strength at 700℃ is 985MPa, the yield strength is 770MPa, the yield strength ratio is 0.78, and the elongation at break is 7%. The tensile strength at 800℃ is 710MPa, the yield strength is 670MPa, the yield strength ratio is 0.94, and the elongation at break is 13%. The tensile strength at 900℃ is 480MPa, the yield strength is 400MPa, the yield strength ratio is 0.83, and the elongation at break is 19%.

[0077] Example 4

[0078] A preparation method of high-density GH4099 alloy by melt forming and hot isostatic pressing, the preparation method of melt forming and hot isostatic pressing comprises the following steps:

[0079] S1. Pretreatment of GH4099 alloy powder: sieving GH4099 nickel-based high-temperature alloy powder with a particle size of 10-200 μm to obtain powder with a specific particle size of 10-53 μm; drying the obtained powder with a specific particle size at a drying temperature of 120° C. for 3 hours to obtain a powder with a specific particle size after drying;

[0080] S2, laser powder bed melting forming: the powder of specific particle size after drying in S1 is placed in the powder bin of the equipment, and the powder of specific particle size after drying placed on the substrate is melted and formed by laser powder bed melting technology. When the bottom area of ​​the forming substrate is 100×100mm, the single-layer forming height is 60μm, and the total forming height is 100mm, the laser power is 300W, the laser spot diameter is 70μm, the scanning speed is 900mm / s, and the scanning interval is 0.12mm, a preliminary formed alloy material is obtained; wherein: the material of the melt-formed substrate is 316L stainless steel, and the melt-forming process requires the substrate to be preheated, and the substrate preheating heating rate is 100℃ / h, and the temperature is 150℃;

[0081] S3. Hot isostatic pressing: After S2 is melt-formed, hot isostatic pressing is performed with a heating rate of 250°C / h, a temperature of 1200°C, a pressure of 180MPa, a holding time of 2h, and a furnace cooling method. The furnace cooling rate is less than 5°C / min above 900°C and less than 1°C / min below 900°C to obtain a high-density GH4099 alloy.

[0082] The porosity of the high-density GH4099 alloy prepared in this embodiment is 0%, the tensile strength is 1190MPa, the yield strength is 715MPa, the yield ratio is 0.60, and the elongation at break is 16%; the high-temperature tensile strength at 700°C is 985MPa, the yield strength is 705MPa, the yield ratio is 0.72, and the elongation at break is 6.5%; the high-temperature tensile strength at 800°C is 710MPa, the yield strength is 630MPa, the yield ratio is 0.89, and the elongation at break is 11%; the high-temperature tensile strength at 900°C is 489MPa, the yield strength is 406MPa, the yield ratio is 0.83, and the elongation at break is 21%.

[0083] Example 5

[0084] A preparation method of high-density GH4099 alloy by melt forming and hot isostatic pressing, the preparation method of melt forming and hot isostatic pressing comprises the following steps:

[0085] S1. Pretreatment of GH4099 alloy powder: sieving GH4099 nickel-based high-temperature alloy powder with a particle size of 10-200 μm to obtain powder with a specific particle size of 10-53 μm; drying the obtained powder with a specific particle size at a drying temperature of 110-120° C. for a drying time of 2 h to obtain a powder with a specific particle size after drying;

[0086] S2, laser powder bed melting forming: the powder of specific particle size after drying in S1 is placed in the powder bin of the equipment, and the powder of specific particle size after drying placed on the substrate is melted and formed by laser powder bed melting technology. When the bottom area of ​​the forming substrate is 20×20mm, the single-layer forming height is 0.04mm, and the total forming height is 80mm, the laser power is 270W, the laser spot diameter is 70μm, the scanning speed is 900mm / s, and the scanning interval is 110μm, a preliminary formed alloy material is obtained; wherein: the material of the melt-formed substrate is 316L stainless steel or 45# steel, and the substrate needs to be preheated during the melting forming process, and the heating rate of the preheating substrate is 100℃ / h, and the temperature is 150℃;

[0087] S3. Hot isostatic pressing: After S2 is melt-formed, hot isostatic pressing is performed with a heating rate of 300°C / h, a temperature of 1200°C, a pressure of 120MPa, a holding time of 2h, and a furnace cooling method. The furnace cooling rate is less than 5°C / min above 900°C and less than 1°C / min below 900°C to obtain a high-density GH4099 alloy.

[0088] The porosity of the high-density GH4099 alloy prepared in this embodiment is 0%, the tensile strength is 1250MPa, the yield strength is 980MPa, the yield ratio is 0.78, and the elongation at break is 25%; the high-temperature tensile strength at 700°C is 1000MPa, the yield strength is 800MPa, the yield ratio is 0.80, and the elongation at break is 10%; the high-temperature tensile strength at 800°C is 730MPa, the yield strength is 700MPa, the yield ratio is 0.95, and the elongation at break is 15%; the high-temperature tensile strength at 900°C is 500MPa, the yield strength is 420MPa, the yield ratio is 0.84, and the elongation at break is 20%.

[0089] Example 6

[0090] A preparation method of high-density GH4099 alloy by melt forming and hot isostatic pressing, the preparation method of melt forming and hot isostatic pressing comprises the following steps:

[0091] S1. Pretreatment of GH4099 alloy powder: sieving GH4099 nickel-based high-temperature alloy powder with a particle size of 10-200 μm to obtain powder with a specific particle size of 10-53 μm; drying the obtained powder with a specific particle size at a drying temperature of 120° C. for a drying time of 2 h to obtain a powder with a specific particle size after drying;

[0092] S2, laser powder bed melting forming: the powder of specific particle size after drying in S1 is placed in the powder bin of the equipment, and the powder of specific particle size after drying placed on the substrate is melted and formed by laser powder bed melting technology. When the bottom area of ​​the forming substrate is 20×80mm, the single-layer forming height is 0.04mm, and the total forming height is 20mm, the laser power is 270W, the laser spot diameter is 70μm, the scanning speed is 900mm / s, and the scanning interval is 110μm, a preliminary formed alloy material is obtained; wherein: the material of the melt-formed substrate is 316L stainless steel or 45# steel, and the melt-forming process requires the substrate to be preheated, and the heating rate of the preheating substrate is 100℃ / h, and the temperature is 150℃;

[0093] S3. Hot isostatic pressing: After S2 is melt-formed, hot isostatic pressing is performed with a heating rate of 300°C / h, a temperature of 1200°C, a pressure of 120MPa, a holding time of 2h, and a furnace cooling method. The furnace cooling rate is less than 5°C / min above 900°C and less than 1°C / min below 900°C to obtain a high-density GH4099 alloy.

[0094] The porosity of the high-density GH4099 alloy prepared in this embodiment is 0%, the tensile strength is 1250MPa, the yield strength is 980MPa, the yield ratio is 0.78, and the elongation at break is 25%; the high-temperature tensile strength at 700°C is 1000MPa, the yield strength is 800MPa, the yield ratio is 0.80, and the elongation at break is 10%; the high-temperature tensile strength at 800°C is 730MPa, the yield strength is 700MPa, the yield ratio is 0.95, and the elongation at break is 15%; the high-temperature tensile strength at 900°C is 500MPa, the yield strength is 420MPa, the yield ratio is 0.84, and the elongation at break is 20%.

[0095] The above scheme, the present invention proposes a preparation method of melt forming and hot isostatic pressing of high-density GH4099 alloy, which can solve the technical problems caused by the traditional high-temperature alloy GH4099 preparation method, such as a high number of hole defects, a high crack occurrence rate, long working hours, high heat consumption, high cost, low efficiency, low precision, inability to prepare products with complex shapes, low density, and low confidence.

[0096] The present invention screens the particle size of the powder and controls the water content, and then forms the GH4099 nickel-based high-temperature alloy through a laser powder bed melting technology, so that the prepared product is free of cracks and the defect rate is greatly reduced.

[0097] The present invention performs hot isostatic pressing on the formed product to make the prepared product fully dense, thereby greatly improving the size, shape accuracy and product confidence of the additively manufactured GH4099 nickel-based high-temperature alloy product.

[0098] In summary, compared with other traditional methods, the method of the present invention uses laser powder bed melting technology to form GH4099 nickel-based high-temperature alloy. The prepared product has no cracks and greatly reduces the defect rate. After the formed product is subjected to hot isostatic pressing treatment, the prepared product can achieve full density, which greatly improves the confidence of additively manufactured GH4099 nickel-based high-temperature alloy products. The method is simple and easy to operate, has high production flexibility, low cost, short process and high efficiency, and provides a high-quality forming and manufacturing method for the hot end components of aerospace engines and gas turbines with complex structures, which is conducive to large-scale industrial production and promotion.

[0099] It should be understood that the term "and / or" in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship, but it may also indicate an "and / or" relationship. Please refer to the context for specific understanding.

[0100] In the present invention, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can be represented by: a, b, c, ab, ac, bc, or abc, where a, b, c can be single or multiple.

[0101] It should be understood that in various embodiments of the present invention, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0102] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for preparing a high-density GH4099 alloy by melt forming and hot isostatic pressing, characterized in that: The preparation method of melt forming and hot isostatic pressing comprises the following steps: S1. Pretreatment of GH4099 alloy powder: sieving GH4099 nickel-based high-temperature alloy powder to obtain powder with a specific particle size; drying the obtained powder with a specific particle size to obtain powder with a specific particle size after drying; S2, laser powder bed melting forming: the powder with a specific particle size after drying in S1 is placed in the powder bin of the equipment, and the powder with a specific particle size after drying placed on the substrate is melted and formed by laser powder bed melting technology to obtain a preliminarily formed alloy material; S3, hot isostatic pressing treatment: After S2 is melt-formed, hot isostatic pressing treatment is performed to obtain a high-density GH4099 alloy.

2. The method for preparing the high-density GH4099 alloy by melt forming and hot isostatic pressing according to claim 1, characterized in that: The particle size of GH4099 nickel-based high-temperature alloy powder in S1 is 10-200 μm, the screening particle size of the powder with a specific particle size is 10-53 μm, the drying temperature is 110-120° C., and the drying time is 2-5 h.

3. The method for preparing the high-density GH4099 alloy by melt forming and hot isostatic pressing according to claim 1, characterized in that: The melting forming process in S2 requires the substrate to be preheated, and the heating rate of the substrate preheating is 100-200°C / h and the temperature is 50-150°C.

4. The method for preparing the high-density GH4099 alloy by melt forming and hot isostatic pressing according to claim 1, characterized in that: The material of the substrate formed by melting in S2 is 316L stainless steel or 45 steel.

5. The method for preparing the high-density GH4099 alloy by melt forming and hot isostatic pressing according to claim 1, characterized in that: In S2, when the powder of a specific particle size after drying is melted and formed by laser powder bed melting technology, the laser power used is 270-300W, the laser spot diameter is 70μm, the scanning speed is 900-1200mm / s, the scanning interval is 90-120μm, and the layer thickness is 0.3-0.6μm.

6. The method for preparing the high-density GH4099 alloy by melt forming and hot isostatic pressing according to claim 1, characterized in that: In S2, when the bottom area of ​​the prepared substrate is 5×5mm-100×100mm, the single-layer forming height is 30-60μm, and the total forming height is 10-100mm.

7. The method for preparing the high-density GH4099 alloy by melt forming and hot isostatic pressing according to claim 1, characterized in that: In S2, when the bottom area of ​​the forming substrate is 30×40 mm, the single-layer forming height is 0.04 mm, and the total forming height is 80 mm, the laser power is 300 W, the laser spot diameter is 70 μm, the scanning speed is 1000 mm / s, and the scanning spacing is 0.11 mm.

8. The method for preparing the high-density GH4099 alloy by melt forming and hot isostatic pressing according to claim 1, characterized in that: The heating rate of hot isostatic pressing treatment in S3 is 250-300℃ / h, the temperature is 1150-1200℃, the pressure is 120-180MPa, the holding time is 2h, and the cooling method is furnace cooling.

9. The method for preparing the high-density GH4099 alloy by melt forming and hot isostatic pressing according to claim 8, characterized in that: In S3, the cooling rate of furnace cooling is less than 5℃ / min above 900℃ and less than 1℃ / min below 900℃.

10. The method for preparing a high-density GH4099 alloy by melt forming and hot isostatic pressing according to claim 1, characterized in that: The porosity of S3 medium-high density GH4099 alloy is 0%, the tensile strength is 1150-1250MPa, the yield strength is 700-980MPa, the yield strength ratio is 0.60-0.78, and the elongation at break is 15-25%; the high temperature tensile strength at 700℃ is 950-1000MPa, the yield strength is 620-800MPa, the yield strength ratio is 0.72-0.80, and the elongation at break is 6-10%; the high temperature tensile strength at 800℃ is 700-730MPa, the yield strength is 610-700MPa, the yield strength ratio is 0.87-0.95, and the elongation at break is 9-15%; the high temperature tensile strength at 900℃ is 475-500MPa, the yield strength is 400-420MPa, the yield strength ratio is 0.80-0.84, and the elongation at break is 15-20%.

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