Ultrahigh-toughness multi-principal-element intermetallic compound, additive manufacturing method thereof and 3D printing product

Abstract

The invention provides an ultrahigh-toughness multi-principal-element intermetallic compound, an additive manufacturing method thereof and a 3D printing product. The intermetallic compound has an A3B type ordered structure; wherein Ni and Co occupy A sites, and Si, Ti and Al occupy B sites; the intermetallic compound also contains boron, and the boron is mainly distributed in the grain boundary; in terms of 100% of the total number of atoms of the intermetallic compound, the content of Ni is 55-65 at.%, the content of Co is 15-25 at.%, the content of Si is 8-13 at.%, the content of Ti is 3-7 at.%, the content of Al is 2-6 at.%, and the content of boron is lt. %, 0.1 at. The novel alloy and the adopted 3D printing preparation technology are expected to synchronously overcome the problems that a traditional intermetallic compound high-temperature structural material is large in room-temperature brittleness and difficult to machine, and the novel alloy has huge application prospects in the key fields of aerospace and the like.

Description

Technical Field

[0001] The present invention relates to an ultra-high strength and toughness multi-principal element intermetallic compound and an additive manufacturing method and a 3D printed product thereof, belonging to the technical field of additive manufacturing. Background Art

[0002] Ordered intermetallic compound alloys are a kind of high-temperature structural material with great potential and have many attractive properties in structural material applications, such as higher strength at high temperatures and excellent creep resistance.

[0003] However, due to the insufficient number of slip systems and weak grain boundaries, they often exhibit severe brittle characteristics, which greatly limits their application as structural materials. On the other hand, the processing performance of such alloys is poor, and it is difficult to prepare parts with complex structures by traditional methods.

[0004] Traditional design methods are mainly based on alloy systems of a single main element and still have similar very serious problems. Summary of the invention

[0005] In order to solve the above technical problems, the object of the present invention is to provide an intermetallic compound having an ordered structure and having high strength and toughness.

[0006] To achieve the above object, the present invention provides an ultra-high strength and toughness multi-principal element intermetallic compound, wherein the intermetallic compound has an A3B type ordered structure;

[0007] Among them, Ni and Co occupy the A position, Si, Ti, and Al occupy the B position;

[0008] The intermetallic compound also contains boron, and the boron is mainly distributed at the grain boundary to strengthen the grain boundary;

[0009] Taking the total number of atoms of the intermetallic compound as 100%, the Ni content is 55-65at.%, the Co content is 15-25at.%, the Si content is 8-13at.%, the Ti content is 3-7at.%, the Al content is 2-6at.%, and the boron content is <0.1at.%.

[0010] According to a specific embodiment of the present invention, preferably, the total content of Ni and Co is 3 to 3.5 times the sum of the three elements Si, Al and Ti.

[0011] According to a specific embodiment of the present invention, preferably, based on the total number of atoms of the intermetallic compound as 100%, the content of Ni is 59.48 at.%, the content of Co is 20 at.%, the content of Si is 11 at.%, the content of Ti is 5.5 at.%, the content of Al is 4 at.%, and the content of boron is 0.02 at.%.

[0012] Compared with most single-principal intermetallic compounds (such as Ni3Al, Ni3Si, etc.), the new multi-principal intermetallic compounds of the present invention have excellent machinability, and parts with complex structures can be quickly prepared by laser 3D printing technology. After solution and aging heat treatment, the tensile strength is as high as 1.62GPa, while maintaining a uniform elongation of 35%. For traditional single-principal intermetallic compounds, on the one hand, their room temperature mechanical properties are poor, their strength is low, and their brittleness is high, making it difficult to meet the application requirements with high service performance requirements; on the other hand, their greater brittleness leads to poor processing performance, and it is difficult to manufacture parts with complex structures through conventional processing methods and emerging 3D printing technologies. Multi-principal intermetallic compounds overcome the shortcomings of the above single-principal intermetallic compounds at the same time, and therefore have great application potential in the industrial field.

[0013] The present invention also provides an additive manufacturing method, wherein the method is based on the above-mentioned intermetallic compound.

[0014] According to a specific embodiment of the present invention, preferably, the method comprises the following steps:

[0015] preparing the intermetallic compound into spherical powder;

[0016] The powder is formed by using a powder spreading laser 3D printer;

[0017] The formed samples are subjected to solution and aging heat treatment to complete the additive manufacturing process.

[0018] According to a specific embodiment of the present invention, preferably, the particle size of the spherical powder is 10-100 μm, more preferably 15-65 μm.

[0019] According to a specific embodiment of the present invention, preferably, the spherical powder is prepared by a gas atomization powder making method.

[0020] According to a specific embodiment of the present invention, preferably, the forming substrate used when forming the powder is 316L stainless steel, and the preheating temperature is 50-200°C.

[0021] According to a specific embodiment of the present invention, preferably, when the powder is formed, the printing parameters include: laser power of 100-300 W, scanning speed of 550-2000 mm / s, overlap spacing of 0.08-0.15 mm, and powder layer thickness of 0.02-0.05 mm.

[0022] According to a specific embodiment of the present invention, preferably, the parameters of the solution and aging heat treatment include: solution temperature of 1000-1200°C, solution time of 1-5h, aging temperature of 600-900°C, aging time of 4-72h, and cooling method of air cooling.

[0023] Compared with traditional processing methods such as casting and forging, laser 3D printing technology can quickly achieve near-net forming of multi-principal intermetallic compounds. The technology has a simple process flow, low cost, and short production cycle, which is conducive to accelerating industrialization.

[0024] The present invention also provides a 3D printed product, which is prepared by the above-mentioned additive manufacturing method.

[0025] According to a specific embodiment of the present invention, the above-mentioned 3D printed product may include:

[0026] Aviation: engine high-pressure turbine blades, low-pressure turbine blades, combustion chambers, turbine discs;

[0027] Aerospace: high temperature thrust chamber;

[0028] Automobile: turbocharger rotors, piston rings and valves of internal combustion engines, automobile body materials;

[0029] Nuclear engineering: Light water reactor components (e.g. cladding) with limited fast neutron irradiation.

[0030] The present invention adopts a new multi-principal component alloy design concept and successfully designs a new intermetallic compound with an L12-type ordered structure (close-packed A3B-type ordered structure) by controllably incorporating multiple alloying elements. The laser-based powder bed 3D printing technology is used to achieve efficient near-net forming of the multi-principal component intermetallic compound. The microstructure is further regulated by subsequent heat treatment to obtain an intermetallic compound with a pure L12 ordered structure. At the same time, the alloy has very excellent tensile properties at room temperature. Its tensile strength can reach 1.62 GPa and its uniform elongation is about 35%, which is far superior to traditional intermetallic compound alloys.

[0031] The new alloy provided by the present invention and the 3D printing preparation technology adopted are expected to simultaneously overcome the problems of high room temperature brittleness and processing difficulties of traditional intermetallic compound high-temperature structural materials, and will have great application prospects in key fields such as aerospace. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a powder morphology image of multi-principal intermetallic compounds, a design drawing of the printing model, a physical image of the printed sample, and a CT image of the internal defect distribution of the printed sample.

[0033] Figure 2The microstructure and phase composition results of the printed sample.

[0034] Figure 3 The microstructure and phase composition results of the heat-treated samples.

[0035] Figure 4 The tensile engineering stress-strain curves of the printed samples and the heat-treated samples.

[0036] Figure 5 Print the internal defects and tensile curve of the sample under higher energy density conditions. DETAILED DESCRIPTION

[0037] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0038] Example 1

[0039] This embodiment provides an additive manufacturing method, wherein:

[0040] The intermetallic compound used has an A3B type ordered structure, wherein Ni and Co occupy the A position, and Si, Ti, and Al occupy the B position; and a trace amount of boron is added to the intermetallic compound as a grain boundary strengthening element;

[0041] Taking the total number of atoms of the intermetallic compound as 100%, the Ni content is 59.48 at.%, the Co content is 20 at.%, the Si content is 11 at.%, the Ti content is 5.5 at.%, the Al content is 4 at.%, and the B (boron element) content is 0.02 at.%.

[0042] The additive manufacturing method comprises the following steps:

[0043] The designed pre-alloyed powder was prepared by gas atomization method, and spherical powder with a particle size of 15-65μm was screened out. The morphology of the powder is as follows Figure 1 As shown in a;

[0044] Before printing, the pre-alloyed powder is dried in a blast drying oven (60℃ / 4h);

[0045] Use 3D printing software to set the printing model and printing parameters, and generate the slice files required for printing; the printing model is as follows Figure 1 As shown in b;

[0046] The printing model file is imported into the selective laser melting device (SLM 125HL laser 3D printer in this embodiment), and the pre-alloyed powder is selectively melted and formed by the printing device. The laser power used is 200W, the scanning speed is 900mm / s, the overlap spacing is 0.12mm, the layer thickness is 0.03mm, and the printed sample is as follows: Figure 1 As shown in c; the internal pores are relatively small, and a sample with a density greater than 99.99% can be obtained ( Figure 1 The microstructure and phase composition of the printed sample are shown in Figure 2 As shown, a is the EBSD orientation map, which reflects that the printed sample has a fine near-equiaxed crystal structure; the average grain size is about 15.5μm, b is the SEM backscattering map, it can be seen that the printed sample has a fine dendrite structure inside the grain, c is the XRD spectrum, d is the TEM bright field image and the selected area electron diffraction map of different regions, Figure 2 Figures c and d show that the printed samples are mainly composed of G phase and L12 phase.

[0047] The sample formed by this parameter was solution treated at 1000℃ for 2h. The microstructure and phase composition of the heat-treated sample are as follows: Figure 3 As shown in the figure, a is the EBSD orientation map, which shows that after solution heat treatment, the sample still presents a fine equiaxed crystal structure, b is the SEM backscattering image, and the dendrite structure inside the grain disappears, c is the XRD image, and d is the TEM bright field image and the selected area electron diffraction image of different regions. Figure 3 It can be seen from c and d in that the solution treatment can eliminate the brittle G phase. Therefore, after solution heat treatment (1000℃ / 2h), the tensile strength is as high as 1.62GPa and the uniform elongation is 35%. Figure 4 shown.

[0048] By comparison, it can be seen that the tensile mechanical properties of the multi-principal metal compound prepared by combining laser 3D printing and heat treatment in Example 1 are far superior to those of the traditional single-principal metal compound alloy, such as the Ni3Al type: the tensile strength is only 650 MPa, and the uniform elongation is 9%.

[0049] Comparative Example

[0050] This comparative example provides an additive manufacturing method, wherein:

[0051] The intermetallic compound used has an A3B type ordered structure, wherein Ni and Co occupy the A position, Si, Ti, and Al occupy the B position, and a trace amount of boron is added as a grain boundary strengthening element;

[0052] Taking the total number of atoms of the intermetallic compound as 100%, the Ni content is 59.5 at.%, the Co content is 20 at.%, the Si content is 11 at.%, the Ti content is 5.5 at.%, the Al content is 4 at.%, and the B content is 0.02 at.%.

[0053] The additive manufacturing method comprises the following steps:

[0054] The designed pre-alloyed powder was prepared by gas atomization method, and spherical powder with a particle size of 15-65μm was screened out. The morphology of the powder is as follows Figure 1 As shown in a;

[0055] Before printing, the pre-alloyed powder is dried in a blast drying oven (60℃ / 4h);

[0056] Use 3D printing software to set the printing model and printing parameters, and generate the slice files required for printing; the printing model is as follows Figure 1 As shown in b;

[0057] The printing model file is imported into the selective laser melting equipment (SLM 125HL laser 3D printer in this embodiment), and the pre-alloyed powder is selectively melted and formed using the printing equipment. The laser power used is 200W, the scanning speed is 500mm / s, the overlap spacing is 0.12mm, and the layer thickness is 0.03mm.

[0058] The samples printed with this parameter have a low scanning speed, resulting in too high energy density, and a large number of pores and other defects appearing inside the material. Therefore, the strength and plasticity of the printed samples are worse than those of the samples in Example 1 (such as Figure 5 shown).

[0059] By comparison, it can be seen that the multi-principal intermetallic compound prepared by combining laser 3D printing and heat treatment in Example 1 not only has a higher density, but also its room temperature tensile properties are far superior to those of traditional single-principal intermetallic compound alloys, such as the Ni3Al type: the tensile strength is only 650 MPa, and the uniform elongation is 9%.

[0060] The 3D printed multi-principal intermetallic compound of the present invention breaks through the inverted strength-ductility relationship of traditional intermetallic compounds for the first time, and has good printability and strong competitiveness in the aerospace field.

Claims

1. An ultra-high strength and toughness multi-principal metal compound, wherein: The intermetallic compound has an A3B type ordered structure; Among them, Ni and Co occupy the A position, Si, Ti, and Al occupy the B position; The intermetallic compound also contains boron, and the boron is mainly distributed in the grain boundaries; Taking the total number of atoms of the intermetallic compound as 100%, the Ni content is 55-65at.%, the Co content is 15-25at.%, the Si content is 8-13at.%, the Ti content is 3-7at.%, the Al content is 2-6at.%, and the boron content is <0.1at.%.

2. The intermetallic compound according to claim 1, wherein The total content of Ni and Co is 3 to 3.5 times the sum of the three elements Si, Al and Ti.

3. The intermetallic compound according to claim 1, wherein Taking the total number of atoms of the intermetallic compound as 100%, the Ni content is 59.48 at.%, the Co content is 20 at.%, the Si content is 11 at.%, the Ti content is 5.5 at.%, the Al content is 4 at.%, and the boron content is 0.02 at.%.

4. An additive manufacturing method, wherein: The method is carried out based on the intermetallic compound described in any one of claims 1 to 3.

5. The method according to claim 4, wherein: The method comprises the following steps: preparing the intermetallic compound into spherical powder; The powder is formed by using a powder spreading laser 3D printer; The formed samples are subjected to solution and aging heat treatment to complete the additive manufacturing process.

6. The method according to claim 5, wherein: The particle size of the spherical pre-alloyed powder is 10-100 μm; preferably, the spherical pre-alloyed powder is prepared by a gas atomization powder making method.

7. The method according to claim 5, wherein: The forming substrate used when forming the powder is 316L stainless steel, and the preheating temperature is 50-200°C.

8. The method according to claim 5 or 7, wherein: When the powder is formed, the printing parameters include: laser power of 100-300W, scanning speed of 550-2000mm / s, overlap spacing of 0.08-0.15mm, and powder layer thickness of 0.02-0.05mm.

9. The method according to claim 5, wherein: The parameters of the solution and aging heat treatment include: solution temperature of 1000-1200° C., solution time of 1-5 h, aging temperature of 600-900° C., aging time of 4-72 h, and air cooling.

10. A 3D printed product, which is prepared by the additive manufacturing method according to any one of claims 4 to 9.

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