3D printing manufacturing method for molybdenum-rhenium alloy part

Abstract

The invention discloses a 3D printing manufacturing method of a molybdenum-rhenium alloy part, and belongs to the technical field of 3D printing, and the 3D printing manufacturing method comprises the following steps: S1, establishing a three-dimensional digital model of the molybdenum-rhenium part to be printed, importing the established three-dimensional digital model into subdivision software for slicing, and importing a slicing result into control software of electron beam printing equipment; according to the method, electron beam printing forming process parameters with the highest density are found, and the problems of powder pushing, powder splashing and the like in the electron beam printing process are effectively reduced by adopting a secondary preheating mode, so that the surface quality and the internal quality of the part are improved, high-quality and efficient additive manufacturing of the molybdenum-rhenium alloy part is realized, and the production cost is reduced. The molybdenum-rhenium alloy parts with high precision and complex geometrical shapes can be manufactured, and compared with a traditional manufacturing method, the electron beam selective melting manufacturing method has the advantages that the parts are formed at a time in the vacuum environment, the machining efficiency is obviously improved, and the higher material utilization rate is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of 3D printing, and in particular relates to a 3D printing manufacturing method for molybdenum-rhenium alloy parts. Background Art

[0002] Molybdenum-rhenium alloy has broad application prospects in aerospace, nuclear industry and electronic devices due to its unique physical and chemical properties, such as excellent high-temperature strength, corrosion resistance, and good electrical and thermal conductivity. However, due to its high melting point, difficulty in crystallization, and susceptibility to cracking, it is difficult to manufacture complex shapes and fine structures using traditional manufacturing methods, limiting its potential in high-performance applications. In addition, the performance of molybdenum-rhenium alloy is stable at high temperatures, but it is easy to generate internal stress during the cooling process, affecting the overall performance of the parts.

[0003] As an advanced additive manufacturing technology, electron beam selective melting technology can accurately melt metal powder through electron beam in a vacuum environment and form three-dimensional parts layer by layer. This 3D printing technology has the characteristics of high manufacturing precision, high material utilization rate, and the ability to manufacture complex geometric shapes, providing new possibilities for the manufacture of molybdenum-rhenium alloy parts. However, the EBSM manufacturing of molybdenum-rhenium alloys still faces some challenges, such as the difficulty in controlling the melting and solidification process of the powder, which is prone to splashing and spheroidization, resulting in defects such as poor fusion, holes and cracks, which greatly reduce the surface quality and performance of the parts. Therefore, a 3D printing manufacturing method for molybdenum-rhenium alloy parts is needed to solve the above problems. Summary of the invention

[0004] The object of the present invention is to provide a 3D printing manufacturing method for molybdenum-rhenium alloy parts to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a 3D printing manufacturing method for molybdenum-rhenium alloy parts, comprising the following steps:

[0006] S1, establish a three-dimensional digital model of the molybdenum-rhenium part to be printed, import the established three-dimensional digital model into the segmentation software for slicing, and import the slicing result into the control software of the electron beam printing device;

[0007] S2, adding the dried alloy powder into the powder cylinder to prepare for electron beam selective melting and forming;

[0008] S3, preheating the substrate in the forming chamber to a preset temperature using an electron beam;

[0009] S4, using a scraper to spread the alloy powder in the powder cylinder on the substrate;

[0010] S5. Preheat the powder bed with a defocused electron beam, and then locally preheat the powder bed area outside the part contour to further sinter the powder in the local area; selectively melt the alloy powder in the cross-sectional area of ​​the part with a focused electron beam; and after melting, keep the powder bed warm with a defocused electron beam;

[0011] S6, rotating the scanning direction, the substrate descends by one powder thickness;

[0012] S7, repeat steps S4, S5 and S6 until the molybdenum-rhenium alloy part is manufactured.

[0013] As a preferred solution, in step "S1", the segmentation thickness of the three-dimensional digital model of the part is 40-60 μm.

[0014] As a preferred solution, in step "S2", the preparation before electron beam selective melting forming includes: cleaning the forming chamber, leveling the substrate, and evacuating the forming chamber. The step of evacuating the forming chamber is: evacuating the forming chamber, and when the vacuum degree of the forming chamber reaches 10 -2 -10 -3 MPa, and then filled with helium. After filling with helium, the vacuum degree is 10 -1 -10 -2 MPa.

[0015] As a preferred solution, in step "S3", the electron beam scanning speed for preheating the substrate is 12-16 m / s, and the preset temperature of the substrate is 800°C-1000°C.

[0016] As a preferred solution, in step "S4", the laying thickness of the alloy powder is 40-60 μm, and the excess powder is sent to the powder dropping bin by a scraper.

[0017] As a preferred solution, in step "S5", the pre-preheating electron beam defocusing amount is 0.2-0.4V, the preheating beam current is 30-40mA, and the preheating time is 20-30s; the secondary preheating electron beam defocusing amount is 0.2-0.4V, the preheating beam current is 20-30mA, and the preheating time is 10-20s.

[0018] As a preferred solution, in step "S5", the defocusing amount of the melting electron beam is 0.01-0.02V, the scanning beam current is 10-20mA, the scanning speed is 0.4-1m / s, and the track spacing is 90-110μm.

[0019] As a preferred solution, in step "S5", the post-heat-keeping electron beam defocusing amount is 0.2-0.4V, the beam current is 30-40mA, and the heat-keeping time is 15-25s.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention finds the electron beam printing process parameters with the highest density, and adopts a secondary preheating method to effectively reduce the problems of "powder pushing" and powder splashing during the electron beam printing process, thereby improving the surface quality and internal quality of parts, and realizing high-quality and efficient additive manufacturing of molybdenum-rhenium alloy parts;

[0022] The present invention can manufacture molybdenum-rhenium alloy parts with high precision and complex geometric shapes. Compared with traditional manufacturing methods, the electron beam selective melting manufacturing method forms parts in one step under a vacuum environment, which significantly improves processing efficiency and has a higher material utilization rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the present invention. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with the embodiments.

[0025] The following examples are used to illustrate the present invention, but they cannot be used to limit the scope of protection of the present invention. The conditions in the examples can be further adjusted according to specific conditions. Simple improvements to the method of the present invention under the premise of the concept of the present invention belong to the scope of protection claimed in the present invention.

[0026] See also Figure 1 The present invention provides a 3D printing manufacturing method for molybdenum-rhenium alloy parts, comprising the following steps:

[0027] S1. Establish a three-dimensional digital model of the cylindrical part to be printed, import the established three-dimensional digital model into the segmentation software for slicing, the slice thickness is 50 μm, and import the slicing result into the control software of the electron beam printing device;

[0028] S2. Dry the alloy powder at 200℃ for 2h, add it to the powder cylinder after it cools to room temperature, clean the forming chamber and level the substrate, evacuate the forming chamber, and the air pressure reaches 10 -3 Mpa, helium is filled in, and the pressure is stabilized at 10 -2 Mpa, turn on high pressure;

[0029] S3, preheating the substrate in the forming chamber by using an electron beam, the electron beam scanning speed is 14.8 m / s, and the preset temperature is 950°C;

[0030] S4, using a scraper to spread the alloy powder in the powder cylinder on the substrate, with the preset powder layer thickness being 50 μm;

[0031] S5. Use an electron beam with a defocus of 0.3V to preheat the powder bed. The preheating parameters are: preheating current of 25mA, preheating time of 25s, and scanning speed of 15.8m / s. Then perform secondary preheating on the powder bed area outside the part contour. The secondary preheating parameters are: preheating current of 25mA, preheating time of 10s, and scanning speed of 12.8m / s. Use a focused electron beam to melt and sinter the part cross section. The melting parameters are: melting current of 10.3mA and scanning speed of 0.4m / s. After melting, use an electron beam with a defocus of 0.4V to post-insulate the powder bed. The post-insulation parameters are: insulation current of 35mA and insulation time of 16s.

[0032] S6, rotating the scanning direction, the substrate descends by one powder thickness;

[0033] S7, repeat steps S4, S5 and S6 until the molybdenum-rhenium alloy part is manufactured.

[0034] The density of the cylindrical parts was tested to be 99.8%, the structure was uniform, and there were no obvious defects such as holes and cracks.

[0035] The working principle and use process of the present invention: A molybdenum-rhenium alloy block is prepared in a comparative example, and the manufacturing method based on electron beam selective melting includes the following steps:

[0036] 1) Establish a three-dimensional digital model of the block parts to be printed, import the established three-dimensional digital model into the segmentation software for slicing, the slice thickness is 60 μm, and import the slicing results into the control software of the electron beam printing equipment;

[0037] 2) Dry the alloy powder at 200℃ for 2h, add it to the powder cylinder after it cools to room temperature, clean the forming chamber and level the substrate, and evacuate the forming chamber to a pressure of 10 -3 Mpa, helium is injected, and the pressure is stabilized at 10 -2 Mpa, turn on high pressure;

[0038] 3) Preheat the substrate in the forming chamber using an electron beam, the electron beam scanning speed is 15m / s, and the preset temperature is 900°C;

[0039] 4) Use a scraper to spread the alloy powder in the powder cylinder on the substrate, and the preset powder layer thickness is 60 μm;

[0040] 5) The powder bed is preheated using an electron beam with a defocus of 0.32V. The preheating parameters are: preheating current of 30mA, preheating time of 23s, and scanning speed of 16.4m / s; the part cross section is melted and sintered using a focused electron beam. The melting parameters are: melting current of 10.3mA and scanning speed of 0.4m / s; after melting, the powder bed is post-heated using an electron beam with a defocus of 0.4V. The post-heating parameters are: heat preservation current of 30mA and heat preservation time of 18s;

[0041] 6) Rotate the scanning direction and the substrate drops one powder thickness;

[0042] 7) Repeat steps 4) to 6) until the molybdenum-rhenium alloy block part is manufactured;

[0043] The test showed that the splashing phenomenon was serious during the preheating printing process, and the density of the parts was 78-83%;

[0044] The molybdenum-rhenium alloy parts manufactured by the present invention have uniform structure, are free of defects such as holes, cracks and unfused parts, have high density, and achieve near-net forming of the molybdenum-rhenium alloy parts.

[0045] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A 3D printing manufacturing method for molybdenum-rhenium alloy parts, characterized in that: The following steps are involved: S1, establish a three-dimensional digital model of the molybdenum-rhenium part to be printed, import the established three-dimensional digital model into the segmentation software for slicing, and import the slicing result into the control software of the electron beam printing device; S2, adding the dried alloy powder into the powder cylinder to prepare for electron beam selective melting and forming; S3, preheating the substrate in the forming chamber to a preset temperature using an electron beam; S4, using a scraper to spread the alloy powder in the powder cylinder on the substrate; S5. Preheat the powder bed with a defocused electron beam, and then locally preheat the powder bed area outside the part contour to further sinter the powder in the local area; selectively melt the alloy powder in the cross-sectional area of ​​the part with a focused electron beam; and after melting, keep the powder bed warm with a defocused electron beam; S6, rotating the scanning direction, the substrate descends by one powder thickness; S7, repeat steps S4, S5 and S6 until the molybdenum-rhenium alloy part is manufactured.

2. The 3D printing manufacturing method of a molybdenum-rhenium alloy part according to claim 1, characterized in that: In step "S1", the segmentation thickness of the three-dimensional digital model of the part is 40-60μm.

3. The 3D printing manufacturing method of a molybdenum-rhenium alloy part according to claim 1, characterized in that: In step "S2", the preparation before electron beam selective melting forming includes: cleaning the forming chamber, leveling the substrate, and evacuating the forming chamber. The steps of evacuating the forming chamber are: evacuating the forming chamber, and when the vacuum degree of the forming chamber reaches 10 -2 -10 -3 MPa, and then filled with helium. After filling with helium, the vacuum degree is 10 -1 -10 -2 MPa.

4. The 3D printing manufacturing method of a molybdenum-rhenium alloy part according to claim 1, characterized in that: In step "S3", the electron beam scanning speed of the substrate preheating is 12-16 m / s, and the preset temperature of the substrate is 800°C-1000°C.

5. The 3D printing manufacturing method of a molybdenum-rhenium alloy part according to claim 1, characterized in that: In step "S4", the alloy powder is laid to a thickness of 40-60 μm, and the excess powder is sent to a powder drop bin by a scraper.

6. The 3D printing manufacturing method of a molybdenum-rhenium alloy part according to claim 1, characterized in that: In step "S5", the pre-preheated electron beam defocusing amount is 0.2-0.4V, the preheated beam current is 30-40mA, and the preheating time is 20-30s; the secondary preheated electron beam defocusing amount is 0.2-0.4V, the preheated beam current is 20-30mA, and the preheating time is 10-20s.

7. The 3D printing manufacturing method of a molybdenum-rhenium alloy part according to claim 1, characterized in that: In step "S5", the melting electron beam defocusing amount is 0.01-0.02V, the scanning beam current is 10-20mA, the scanning speed is 0.4-1m / s, and the track spacing is 90-110μm.

8. The 3D printing manufacturing method of a molybdenum-rhenium alloy part according to claim 1, characterized in that: In step "S5", the electron beam defocusing amount of the post-insulation is 0.2-0.4V, the beam current is 30-40mA, and the insulation time is 15-25s.

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