Method for manufacturing gradient-structured metal part on the basis of additive manufacturing technology

Abstract

A method for manufacturing a gradient-structured metal part on the basis of an additive manufacturing technology, comprising the following steps: step a, modeling a metal part to be additively manufactured, slicing the established metal part model into layers, and importing layered processing information into an additive manufacturing apparatus; step b, setting a printing parameter value of the additive manufacturing apparatus to a first printing parameter value, and the additive manufacturing apparatus printing N1 layers; step c, switching the printing parameter value of the additive manufacturing apparatus to a second printing parameter value, and the additive manufacturing apparatus resuming printing N2 layers; step d, switching the printing parameter value of the additive manufacturing apparatus to a third printing parameter value, and the additive manufacturing apparatus resuming printing N3 layers; step e, cyclically executing steps c to d; and step f, repeatedly executing step c, and repeatedly executing step b to complete the printing.

Description

Method for preparing gradient structure metal parts based on additive manufacturing technology

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on September 19, 2023, with application number 202311212251.1, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of metal additive manufacturing, for example, to a method for preparing gradient structure metal parts based on additive manufacturing technology. Background Art

[0003] Metal additive manufacturing technology (three-dimensional (3D) printing) can produce complex components by using focused high-heat energy (laser, electron beam, or arc) and the corresponding material (powder or wire) to deposit layer by layer. Gradient materials are composed of fine-grained and coarse-grained structures. The structural unit size between these two parts varies continuously and gradiently, and the grain boundary density varies spatially and gradiently. This corresponds to the spatial gradient variation of many physical and chemical properties. Unlike the simple mixing or compounding of structures with different characteristic sizes (such as nano-grains, submicron grains, and coarse grains), the gradient structure effectively avoids the performance mutation caused by the sudden change of the structural characteristic size. It can coordinate structures with different characteristic sizes, and optimize and improve the overall performance and service behavior of the material. If the component materials of a metal part have a gradient structure, the metal part will have good toughness, wear resistance, corrosion resistance, high fatigue strength and other properties.

[0004] Summary of the Invention

[0005] The present application provides a method for preparing a gradient structure metal part based on additive manufacturing technology, so as to manufacture a metal part with a gradient structure and improve the mechanical properties of the metal part.

[0006] The present application provides a method for preparing a gradient structure metal part based on additive manufacturing technology, comprising: modeling the metal part to be additively manufactured, slicing and layering the established metal part model, and importing the layered processing information into an additive manufacturing device; setting the printing parameter value of the additive manufacturing device to a first printing parameter value, and the additive manufacturing device printing N1 layers, where N1 is a positive integer; switching the printing parameter value of the additive manufacturing device to a second printing parameter value, and the additive manufacturing device continuing to print N2 layers, where N2 is a positive integer; switching the printing parameter value of the additive manufacturing device to a third printing parameter value, and the additive manufacturing device continuing to print N2 layers, where N2 is a positive integer. Continue printing N3 layers, where N3 is a positive integer; loop execution to switch the printing parameter value of the additive manufacturing device to the second printing parameter value, the additive manufacturing device continues to print N2 layers, and switch the printing parameter value of the additive manufacturing device to the third printing parameter value, the additive manufacturing device continues to print N3 layers, until the number of cycles reaches the set requirement; repeatedly execute the switching of the printing parameter value of the additive manufacturing device to the second printing parameter value, the additive manufacturing device continues to print N2 layers, repeatedly execute the setting of the printing parameter value of the additive manufacturing device to the first printing parameter value, the additive manufacturing device prints N1 layer, and completes printing.

[0007] The additive manufacturing equipment adopts laser additive manufacturing equipment; the printing parameter value of the additive manufacturing equipment is set to the first printing parameter value, and the additive manufacturing equipment prints the N1 layer, including: setting the laser power value of the laser additive manufacturing equipment to the first laser power value, and then performing the printing work; the printing parameter value of the additive manufacturing equipment is switched to the second printing parameter value, and the additive manufacturing equipment continues to print the N2 layer, including: switching the laser power value of the laser additive manufacturing equipment to the second laser power value, and then continuing the printing work; the printing parameter value of the additive manufacturing equipment is switched to the third printing parameter value, and the additive manufacturing equipment continues to print the N3 layer, including: switching the laser power value of the laser additive manufacturing equipment to the third laser power value, and then continuing the printing work.

[0008] The first laser power value is greater than the third laser power value, and the third laser power value is greater than the second laser power value.

[0009] The additive manufacturing equipment adopts laser additive manufacturing equipment; the printing parameter value of the additive manufacturing equipment is set to the first printing parameter value, and the additive manufacturing equipment prints the N1 layer, including: setting the scanning speed value of the laser additive manufacturing equipment to the first scanning speed value, and then performing the printing work; the printing parameter value of the additive manufacturing equipment is switched to the second printing parameter value, and the additive manufacturing equipment continues to print the N2 layer, including: switching the scanning speed value of the laser additive manufacturing equipment to the second scanning speed value, and then continuing the printing work; the printing parameter value of the additive manufacturing equipment is switched to the third printing parameter value, and the additive manufacturing equipment continues to print the N3 layer, including: switching the scanning speed value of the laser additive manufacturing equipment to the third scanning speed value, and then continuing the printing work.

[0010] The third scanning speed value is greater than the second scanning speed value and less than the first scanning speed value, or the third scanning speed value is greater than the first scanning speed value and less than the second scanning speed value.

[0011] The additive manufacturing equipment adopts electron beam additive manufacturing equipment; the printing parameter value of the additive manufacturing equipment is set to the first printing parameter value, and the additive manufacturing equipment prints the N1 layer, including: setting the electron beam current intensity value of the electron beam additive manufacturing equipment to the first electron beam current intensity value, and then performing the printing work; the printing parameter value of the additive manufacturing equipment is switched to the second printing parameter value, and the additive manufacturing equipment continues to print the N2 layer, including: switching the electron beam current intensity value of the electron beam additive manufacturing equipment to the second electron beam current intensity value, and then continuing the printing work; the printing parameter value of the additive manufacturing equipment is switched to the third printing parameter value, and the additive manufacturing equipment continues to print the N3 layer, including: switching the electron beam current intensity value of the electron beam additive manufacturing equipment to the third electron beam current intensity value, and then continuing the printing work.

[0012] The first electron beam current intensity value is greater than the third electron beam current intensity value, and the third electron beam current intensity value is greater than the second electron beam current intensity value.

[0013] The raw material used by the additive manufacturing equipment to print the gradient structure metal part is metal powder.

[0014] The process of modeling the metal part to be additively manufactured, slicing and layering the established metal part model, and importing the layered processing information into the additive manufacturing equipment includes: drying the metal powder.

[0015] The metal powder is titanium alloy powder, stainless steel powder, aluminum alloy powder or titanium-based composite material powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG1 is a schematic flow chart of a method for preparing a gradient structure metal part based on additive manufacturing technology provided in Example 1 of the present application;

[0017] FIG2 is a schematic diagram of the grain structure of a metal part printed in Example 2 of the present application;

[0018] FIG3 is a schematic diagram of the grain structure of the metal part printed in Example 3 of the present application. DETAILED DESCRIPTION

[0019] The structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification so that people familiar with this technology can understand and read them. They are not used to limit the conditions for the implementation of this application and therefore have no substantial technical significance. Any modification of the structure, change in the proportion relationship, or adjustment of the size should still fall within the scope of the technical content disclosed in this application without affecting the efficacy and purpose of this application. At the same time, terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description and are not used to limit the scope of the implementation of this application. Changes or adjustments in their relative relationships should also be considered as the scope of the implementation of this application without substantially changing the technical content.

[0020] Example 1

[0021] As shown in FIG1 , this embodiment provides a method for preparing a gradient structure metal part based on additive manufacturing technology, which includes the following steps.

[0022] Step a: Model the metal part to be additively manufactured, slice and layer the established metal part model, and import the layered processing information into the additive manufacturing equipment.

[0023] Step b: setting the printing parameter value of the additive manufacturing device to a first printing parameter value, and the additive manufacturing device prints N1 layers, where N1 is a positive integer.

[0024] Step c: Switch the printing parameter value of the additive manufacturing device to a second printing parameter value, and the additive manufacturing device continues to print N2 layers, where N2 is a positive integer.

[0025] Step d: Switch the printing parameter value of the additive manufacturing device to a third printing parameter value, and the additive manufacturing device continues to print N3 layers, where N3 is a positive integer.

[0026] Step e: cyclically execute steps c to d until the number of cycles reaches the set requirement.

[0027] Step f: Repeat step c and step b to complete printing.

[0028] This method for preparing gradient structure metal parts uses additive manufacturing equipment to print metal parts. During the printing process, the printing parameters of the additive manufacturing equipment are repeatedly adjusted to achieve periodic alternating changes in the printing parameters, thereby printing metal parts with gradient structures, thereby improving the performance and quality of the metal parts.

[0029] In this embodiment, the additive manufacturing equipment adopts a laser additive manufacturing equipment. In this embodiment, the additive manufacturing equipment can be a selective laser melting (SLM) additive manufacturing equipment or a directed energy deposition (DED) additive manufacturing equipment. In step b of this embodiment, the laser power value of the laser additive manufacturing equipment is set to a first laser power value, and then the printing operation is performed, that is, the printing parameter value in this embodiment includes the laser power value, and the first printing parameter value includes the first laser power value. In step c of this embodiment, the laser power value of the laser additive manufacturing equipment is switched to a second laser power value, and then the printing operation is continued, that is, the second printing parameter value in this embodiment includes the second laser power value. In step d of this embodiment, the laser power value of the laser additive manufacturing equipment is switched to a third laser power value, and then the printing operation is continued, that is, the third printing parameter value in this embodiment includes the third laser power value. And the first laser power value is greater than the third laser power value, and the third laser power value is greater than the second laser power value.

[0030] In steps b to f, printing is performed using metal powder as raw material; the metal powder may be titanium alloy powder, stainless steel powder, aluminum alloy powder or titanium-based composite material powder; and the powder coating thickness is 30 μm-90 μm.

[0031] In addition, in steps b through f of this embodiment, in an argon atmosphere, O2 < 500 ppm and a chamber pressure of 40 mbar. The laser used in the laser additive manufacturing equipment of this embodiment is a continuous laser. In steps a through f of this embodiment, the laser power ranges from 100W to 3000W, the laser spot diameter ranges from 10μm to 200μm, and the scanning speed ranges from 10mm / s to 2000mm / s. The selection of laser power density and scanning speed requires validation of the strategy using a finite element thermal model.

[0032] The method for preparing a gradient structure metal part based on additive manufacturing technology in this embodiment includes the following steps.

[0033] Step a: Before printing, heat the metal powder to 120°C in a vacuum oven and keep it warm for 2 hours to dry the metal powder; perform 3D modeling on the metal part to be additively manufactured, slice and layer the established metal part model, divide the number of printing layers, and import the layered processing information into the control system of the additive manufacturing equipment.

[0034] Step b: setting the laser power value of the laser additive manufacturing equipment to a first laser power value, and the laser additive manufacturing equipment first prints two layers, that is, N1 is 2 in this embodiment.

[0035] Step c: setting the laser power value of the laser additive manufacturing equipment to a second laser power value, and the laser additive manufacturing equipment continues to print 6 layers, that is, N2 is 6 in this embodiment.

[0036] Step d: setting the laser power value of the laser additive manufacturing equipment to a third laser power value, and the laser additive manufacturing equipment continues to print 3 layers, that is, N3 is 3 in this embodiment.

[0037] Step e: cyclically execute steps c to d, with the number of cycles being an even number.

[0038] Step f: Repeat step c and step b to complete printing.

[0039] During the metal part printing process, this embodiment repeatedly adjusts the laser power of the additive manufacturing equipment, allowing it to periodically alternatingly change. This allows the printing of metal parts with a gradient structure, i.e., a gradient structure with a coarse-fine grain distribution, thereby improving the overall mechanical properties of the metal part. The surface layer produced in this embodiment retains multiple equiaxed grains resulting from the transition from columnar to equiaxed at the top of the molten pool, while the interior contains nearly columnar grains formed by smaller power or speed differences. This results in superior mechanical properties and significantly reduces anisotropy in the crystal structure and properties.

[0040] During the printing process, an extremely high temperature gradient is triggered before the solid / liquid interface. Therefore, nucleation is easily suppressed in a small melt pool (50-5000μm). Therefore, the particles grow epitaxially from the particles of the adjacent layer previously deposited on the substrate, and the formed microstructure usually presents long columnar particles along the building direction. This embodiment proposes an in-situ process parameter adjustment strategy. This technical solution retains the equiaxed grains obtained by the columnar to equiaxed transition (CET) at the top of the molten pool, and retains the fully equiaxed crystal structure at a certain depth in the surface layer based on step b. When printing the intermediate parts of the metal parts, based on steps c to e, a large number of layers are alternately and continuously printed, and columnar grains are grown again based on the equiaxed grains. Due to the competitive growth of grains and the large number of printed layers, the morphology of the epitaxially grown grains obtained approaches coarse equiaxed crystals. In-situ regulation is achieved to promote the formation of gradient organization without changing the alloy composition and adding auxiliary equipment, thereby reducing cost and time. In the process of printing and forming metal parts, the tensile and fatigue properties of the final molded parts can be improved, crack propagation can be inhibited, and the application field of additive manufacturing metal materials can be greatly expanded.

[0041] Example 2

[0042] This embodiment, based on the first embodiment, utilizes Ti-6Al-4V alloy metal powder. Furthermore, the additive manufacturing equipment employed in this embodiment is a DED additive manufacturing device. The first laser power is 2400W, the second laser power is 1200W, and the third laser power is 1800W.

[0043] This embodiment provides a method for preparing a gradient structure metal part based on additive manufacturing technology, which includes the following steps.

[0044] Step a: Before printing, heat Ti-6Al-4V alloy metal powder to 120°C in a vacuum oven and keep it warm for 2 hours to dry the metal powder; perform 3D modeling on the metal part to be additively manufactured, slice and layer the established metal part model, and divide the printing layer number into 109 layers; import the layered processing information into the control system of the DED additive manufacturing equipment.

[0045] Step b: Set the laser power value of the DED additive manufacturing equipment to 2400 W, the scanning speed to 10 mm / s, the laser spot diameter to 5 μm, lay the Ti-6Al-4V alloy metal powder to a thickness of 300 μm, and use the DED additive manufacturing equipment to print two layers continuously.

[0046] Step c: Switch the laser power value of the DED additive manufacturing equipment to 1200W, keep other parameters unchanged, and continue printing 6 layers.

[0047] Step d: Switch the laser power value of the DED additive manufacturing equipment to 1800W, keep other parameters unchanged, and continue printing 3 layers.

[0048] Step e: loop through steps c to d for 10 cycles.

[0049] Step f: Repeat step c and step b to complete printing.

[0050] In this embodiment, the method for preparing a metal part with a gradient structure is performed by cyclically executing steps c through d during the metal part printing process, achieving a periodic alternating change in laser power, thereby printing a metal part with a gradient structure, as shown in Figure 2. The resulting metal part has a tensile strength of 990 MPa, an elongation of 14.2%, and a fatigue strength of 475 MPa.

[0051] Example 3

[0052] Based on the above-mentioned embodiment 2, this embodiment mainly realizes the printing of metal parts with gradient structures by changing the laser scanning speed. Therefore, in step b of this embodiment, the scanning speed value of the laser additive manufacturing equipment is set to the first scanning speed value, and then the printing work is carried out. In this embodiment, the printing parameter value includes the scanning speed value, and the first printing parameter value includes the first scanning speed value. In step c of this embodiment, the scanning speed value of the laser additive manufacturing equipment is switched to the second scanning speed value, and then the printing work is continued. That is, the second printing parameter value in this embodiment includes the second scanning speed value. In step d of this embodiment, the scanning speed value of the laser additive manufacturing equipment is switched to the third scanning speed value, and then the printing work is continued. That is, the third printing parameter value in this embodiment includes the third scanning speed value. In this embodiment, the first scanning speed value < the third scanning speed value < the second scanning speed value.

[0053] This embodiment provides a method for preparing a gradient structure metal part based on additive manufacturing technology, which includes the following steps.

[0054] Step a: Before printing, heat Ti-6Al-4V alloy metal powder to 120°C in a vacuum oven and keep it warm for 2 hours to dry the metal powder; perform 3D modeling on the metal part to be additively manufactured, and slice and layer the established metal part model, dividing the number of printing layers into 199 layers; and import the layered processing information into the control system of the DED additive manufacturing equipment.

[0055] Step b: Set the laser power value of the DED additive manufacturing equipment to 2400 W, the scanning speed value to 10 mm / s, the laser spot diameter to 5 μm, lay the Ti-6Al-4V alloy metal powder to a thickness of 300 μm, and use the DED additive manufacturing equipment to print two layers continuously.

[0056] Step c: Switch the scanning speed of the DED additive manufacturing equipment to 20 mm / s, keep other parameters unchanged, and continue printing 6 layers.

[0057] Step d: Switch the scanning speed of the DED additive manufacturing equipment to 15 mm / s, keep other parameters unchanged, and continue printing 3 layers.

[0058] Step e: loop through steps c to d, with the number of loops being 20.

[0059] Step f: Repeat step c and step b to complete printing.

[0060] In this embodiment, the additive manufacturing method for preparing a metal part with a gradient structure employs a cyclical scanning speed change through steps c through d, thereby printing a metal part with a gradient structure, as shown in Figure 3. The resulting metal part with a gradient structure exhibited a tensile strength of 922 MPa, an elongation of 16.8%, and a fatigue strength of 453 MPa.

[0061] Example 4

[0062] In this embodiment, based on the above-mentioned embodiment 2, the first laser power value is adjusted to 480W, the second laser power value is adjusted to 100W, and the third laser power value is adjusted to 280W. In this embodiment, the metal powder is 316L alloy metal powder. In this embodiment, the additive manufacturing equipment is a SLM additive manufacturing equipment.

[0063] This embodiment provides a method for preparing a gradient structure metal part based on additive manufacturing technology, which specifically includes the following steps.

[0064] Step a: Before printing, heat 316L alloy metal powder to 120°C in a vacuum oven and keep it warm for 2 hours to dry the metal powder; perform 3D modeling on the metal part to be additively manufactured, slice and layer the established metal part model, and divide the number of printing layers; import the layered processing information into the control system of the SLM additive manufacturing equipment.

[0065] Step b: Set the laser power value of the SLM additive manufacturing equipment to 480W, the scanning speed value to 1000mm / s, the laser spot diameter to 60μm, lay the 316L alloy metal powder to a thickness of 60μm, and use the SLM additive manufacturing equipment to print 2 layers continuously.

[0066] Step c: Switch the laser power value of the SLM additive manufacturing equipment to 100W, keep other parameters unchanged, and continue printing 6 layers.

[0067] Step d: Switch the laser power value of the SLM additive manufacturing equipment to 280W, keep other parameters unchanged, and continue printing 3 layers.

[0068] Step e: cyclically execute steps c to d, with the number of cycles being 40 times.

[0069] Step f: Repeat step c and step b to complete printing.

[0070] In this embodiment, a metal part with a gradient structure is processed based on the above method, and the final metal part has a tensile strength of 580 MPa, an elongation of 64.7%, and a fatigue strength of 315 MPa.

[0071] Example 5

[0072] In this example, based on the third example above, the first scanning speed is adjusted to 1800 mm / s, the second scanning speed is adjusted to 600 mm / s, and the third scanning speed is adjusted to 1000 mm / s. Thus, the first scanning speed is greater than the third scanning speed, which is greater than the second scanning speed. This example uses In718 alloy metal powder as the printing material, and the additive manufacturing equipment used is an SLM.

[0073] This embodiment provides a method for preparing a gradient structure metal part based on additive manufacturing technology, which specifically includes the following steps.

[0074] Step a: Before printing, heat the In718 alloy metal powder to 120°C in a vacuum oven and keep it warm for 2 hours to dry the metal powder; perform 3D modeling on the metal part to be additively manufactured, slice and layer the established metal part model, and divide the number of printing layers; import the layered processing information into the control system of the SLM additive manufacturing equipment.

[0075] Step b: Set the laser power value of the SLM additive manufacturing equipment to 200 W, the scanning speed value to 1800 mm / s, the laser spot diameter to 60 μm, lay the In718 alloy metal powder to a thickness of 60 μm, and use the SLM additive manufacturing equipment to print two layers continuously.

[0076] Step c: Switch the scanning speed of the SLM additive manufacturing equipment to 600 mm / s, keep other parameters unchanged, and continue printing 6 layers.

[0077] Step d: Switch the scanning speed of the SLM additive manufacturing equipment to 1000 mm / s, keep other parameters unchanged, and continue printing 3 layers.

[0078] Step e: loop through steps c to d, with the number of loops being 20.

[0079] Step f: Repeat step c and step b to complete printing.

[0080] The metal part with a gradient structure finally obtained in this embodiment has a tensile strength of 1297 MPa, an elongation of 24.4%, and a fatigue strength of 588 MPa.

[0081] Example 6

[0082] In this embodiment, based on the above-mentioned second embodiment, the additive manufacturing equipment is replaced with an electron beam additive manufacturing equipment, and an electron beam melting (EBM) additive manufacturing equipment is selected. In step b of this embodiment, the electron beam current intensity value of the electron beam additive manufacturing equipment is set to a first electron beam current intensity value before printing is performed. That is, in this embodiment, the printing parameter value includes the electron beam current intensity value, the first printing parameter value includes the first electron beam current intensity value, and the first electron beam current intensity value is specifically 25mA. In step c of this embodiment, the electron beam current intensity value of the electron beam additive manufacturing equipment is switched to a second electron beam current intensity value before printing is continued. That is, in this embodiment, the second printing parameter value includes the second electron beam current intensity value, and the second electron beam current intensity value is specifically 10mA. In step d of this embodiment, the electron beam current intensity value of the electron beam additive manufacturing equipment is switched to a third electron beam current intensity value before printing is continued. That is, in this embodiment, the third printing parameter value includes the third electron beam current intensity value; in this embodiment, the third electron beam current intensity value is specifically 15mA. In this embodiment, the first electron beam current intensity value is greater than the third electron beam current intensity value, and the third electron beam current intensity value is greater than the second electron beam current intensity value. In steps b to f of this embodiment, the parameters of the electron beam additive manufacturing equipment are: electron beam spot diameter of 30μm-100μm, and electron beam intensity of 5mA-50mA.

[0083] This embodiment provides a method for preparing a gradient structure metal part based on additive manufacturing technology, which specifically includes the following steps.

[0084] Step a: Before printing, heat Ti-6Al-4V alloy metal powder to 120°C in a vacuum oven and keep it warm for 2 hours to dry the metal powder; perform 3D modeling on the metal part to be additively manufactured, slice and layer the established metal part model, and divide the number of printing layers; import the layered processing information into the control system of the EBM additive manufacturing equipment.

[0085] Step b: Set the electron beam intensity value of the electron gun of the EBM additive manufacturing equipment to 25 mA, the scanning speed to 500 mm / s, the electron beam spot diameter to 80 μm, and use the EBM additive manufacturing equipment to continuously print two layers.

[0086] Step c: Switch the electron beam current intensity of the EBM equipment to 10 mA, keep other parameters unchanged, and continue printing 6 layers.

[0087] Step d: Switch the electron beam current intensity value of the EBM additive manufacturing equipment to 15mA, keep other parameters unchanged, and continue printing 3 layers.

[0088] Step e: loop through steps c to d, with the number of loops being 20.

[0089] Step f: Repeat step c and step b to complete printing.

[0090] In this embodiment, a metal part with a gradient structure is processed based on the above method, and the final metal part has a tensile strength of 1016 MPa, an elongation of 16.8%, and a fatigue strength of 700 MPa.

[0091] In other embodiments, during the process of printing a metal part using an electron beam additive manufacturing device, the scanning speed is 1000 mm / s-15000 mm / s.

[0092] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical concepts disclosed in this application shall be covered by the claims of this application.

Claims

1. A method for preparing a gradient structure metal part based on additive manufacturing technology, comprising: Model the metal parts to be manufactured by additive manufacturing, slice and layer the established metal parts model, and import the layered processing information into the additive manufacturing equipment; Setting the printing parameter value of the additive manufacturing device to a first printing parameter value, the additive manufacturing device printing N1 layers, where N1 is a positive integer; Switching the printing parameter value of the additive manufacturing device to a second printing parameter value, and the additive manufacturing device continues to print N2 layers, where N2 is a positive integer; Switching the printing parameter value of the additive manufacturing device to a third printing parameter value, and the additive manufacturing device continues to print N3 layers, where N3 is a positive integer; The printing parameter value of the additive manufacturing device is switched to the second printing parameter value, and the additive manufacturing device continues to print the N2 layer, and the printing parameter value of the additive manufacturing device is switched to the third printing parameter value, and the additive manufacturing device continues to print the N3 layer, until the number of cycles reaches the set requirement; Repeat the process of switching the printing parameter value of the additive manufacturing device to the second printing parameter value, and the additive manufacturing device continues to print the N2 layer. Repeat the process of setting the printing parameter value of the additive manufacturing device to the first printing parameter value, and the additive manufacturing device prints the N1 layer to complete printing.

2. The method according to claim 1, wherein: The additive manufacturing equipment adopts laser additive manufacturing equipment; The step of setting the printing parameter value of the additive manufacturing device to the first printing parameter value, and the additive manufacturing device printing the N1 layer, comprises: setting the laser power value of the laser additive manufacturing device to the first laser power value, and then performing the printing operation; The step of switching the printing parameter value of the additive manufacturing device to the second printing parameter value, and the additive manufacturing device continuing to print the N2 layer, includes: switching the laser power value of the laser additive manufacturing device to the second laser power value, and then continuing the printing work; Switching the printing parameter value of the additive manufacturing device to the third printing parameter value, and the additive manufacturing device continuing to print the N3 layer, includes: switching the laser power value of the laser additive manufacturing device to the third laser power value, and then continuing the printing work.

3. The method according to claim 2, wherein: The first laser power value is greater than the third laser power value, and the third laser power value is greater than the second laser power value.

4. The method according to claim 1, wherein: The additive manufacturing equipment adopts laser additive manufacturing equipment; The printing parameter value of the additive manufacturing device is set to a first printing parameter value, the additive manufacturing device The manufacturing device prints the N1 layer, including: setting the scanning speed value of the laser additive manufacturing device to a first scanning speed value, and then performing printing; The step of switching the printing parameter value of the additive manufacturing device to a second printing parameter value, and the additive manufacturing device continuing to print the N2 layer, comprises: Switching the scanning speed value of the laser additive manufacturing device to a second scanning speed value, and then continuing the printing work; The step of switching the printing parameter value of the additive manufacturing device to the third printing parameter value, and the additive manufacturing device continuing to print the N3 layer, includes: switching the scanning speed value of the laser additive manufacturing device to the third scanning speed value, and then continuing the printing work.

5. The method according to claim 4, wherein: The third scanning speed value is greater than the second scanning speed value and less than the first scanning speed value, or the third scanning speed value is greater than the first scanning speed value and less than the second scanning speed value.

6. The method according to claim 1, wherein: The additive manufacturing equipment adopts electron beam additive manufacturing equipment; The step of setting the printing parameter value of the additive manufacturing device to the first printing parameter value, wherein the additive manufacturing device prints the N1 layer, comprises: setting the electron beam current intensity value of the electron beam additive manufacturing device to the first electron beam current intensity value, and then performing the printing operation; The step of switching the printing parameter value of the additive manufacturing device to the second printing parameter value, and the additive manufacturing device continuing to print the N2 layer, includes: switching the electron beam current intensity value of the electron beam additive manufacturing device to the second electron beam current intensity value, and then continuing the printing work; Switching the printing parameter value of the additive manufacturing device to the third printing parameter value, and the additive manufacturing device continuing to print the N3 layer, includes: switching the electron beam current intensity value of the electron beam additive manufacturing device to the third electron beam current intensity value, and then continuing the printing work.

7. The method according to claim 6, wherein: The first electron beam current intensity value is greater than the third electron beam current intensity value, and the third electron beam current intensity value is greater than the second electron beam current intensity value.

8. The method according to claim 1, wherein: The raw material used by the additive manufacturing equipment to print the gradient structure metal part is metal powder.

9. The method according to claim 8, wherein: The process of modeling the metal part to be additively manufactured, slicing and layering the established metal part model, and importing the layered processing information into the additive manufacturing equipment includes: drying the metal powder.

10. The method according to claim 8, wherein: The metal powder is titanium alloy powder, stainless steel powder, aluminum alloy powder or titanium-based composite material powder.

Images