Additive manufacturing of high performance aluminum-titanium metal matrix composites and methods of making the same

Abstract

The application belongs to the field of aluminum-based composite materials, and particularly relates to a kind of additive manufacturing high-performance aluminum-titanium metal composite material and a preparation method thereof. Micron-sized aluminum alloy powder and micron-sized titanium alloy powder are mixed uniformly by ultrasonic-assisted water bath stirring method for laser powder bed melting, wherein the mass fraction of the aluminum alloy powder and the titanium alloy powder is 85-98 wt.% and 2-15 wt.% respectively. The micron-sized titanium alloy powder is used to promote the formation of multi-scale layered structure of equiaxed crystal, core-shell structure, cellular substructure and nano precipitate phase, so as to simultaneously improve the strength and plasticity of the material and realize isotropic mechanical properties. The aluminum alloy-titanium metal composite material for additive manufacturing disclosed by the application has simple and easy-to-control process and low cost, and can be suitable for large-scale production.

Description

Technical Field

[0001] This invention relates to the field of aluminum-based composite materials, specifically to an additive manufacturing high-performance aluminum-titanium metal composite material and its preparation method. Background Technology

[0002] Laser powder bed melting (LBD) is an additive manufacturing technology that achieves moldless component forming by layer-by-layer deposition of materials. It organically integrates material preparation and precise forming, and manufactures complex three-dimensional shapes by discretizing them into simple two-dimensional planar shapes through layer-by-layer stacking. This overcomes the limitations of traditional processes in terms of complex structural design and design freedom, enabling truly free manufacturing. Currently, LBD technology has been successfully used to prepare high-performance iron-based alloys, titanium alloys, and nickel-based alloys. However, the inherent high thermal conductivity, easy oxidation, and high reflectivity of aluminum alloys make efficient laser deposition difficult, thus limiting the application of additive manufacturing of aluminum alloy components. However, aluminum-based composite materials modified with high-temperature resistant and wear-resistant nanoparticles (such as TiB2, TiC, TiN, and Y2O3) have been widely proven to have good laser weldability, while also exhibiting functional properties such as high-temperature resistance and wear resistance. Among them, nano-ceramic particles play a role in the melting / solidification process of aluminum alloys by (1) improving laser absorption rate; (2) refining grains as heterogeneous nucleation particles and eliminating material anisotropy caused by grain epitaxial growth; and (3) pinning grain boundaries as a second phase. However, nano-sized ceramic particles are prone to agglomeration due to the influence of van der Waals forces between them. Therefore, achieving uniform particle modification is technically challenging and also limits the amount of ceramic particles added to a certain extent. Although ceramic particles, as a hard and brittle phase, improve the strength of aluminum matrix composites by hindering dislocation movement during deformation, cracks are prone to occur at the interface, leading to dislocation pile-up and decreased plasticity. The mismatch between strength and plasticity is a challenge that needs to be overcome in ceramic particle-modified aluminum matrix composites. Therefore, developing a new type of high-strength and high-toughness aluminum matrix composite material with simple process and easy forming is of great significance for promoting the functional application of laser additive manufacturing of aluminum alloy components. Summary of the Invention

[0003] In view of the problems existing in the prior art, the purpose of this invention is to provide a high-performance aluminum-titanium metal composite material for additive manufacturing and its preparation method. Micron-sized titanium alloy and aluminum alloy spherical powders are uniformly mixed using an ultrasonic-assisted water bath stirring method. The high growth limiting factor Ti element achieves equiaxed aluminum grains, thereby eliminating anisotropy. Furthermore, the α and β phases in the titanium alloy have the ability to improve the coordinated deformation of the aluminum matrix. The TiAl nanophase generated by element diffusion improves the mechanical properties of the composite material.

[0004] To achieve this objective, the present invention adopts the following technical solution:

[0005] To address the aforementioned technical problems, according to one aspect of the present invention, the present invention provides the following technical solution:

[0006] This invention provides a high-performance aluminum-titanium metal composite material manufactured by additive manufacturing. The metal composite material is made from aluminum alloy powder and titanium alloy powder by 3D printing. The density of the metal composite material is greater than 99%. In the raw materials, the mass fraction of titanium alloy is 2 to 15 wt.%. The metal composite material contains a multi-scale layered structure.

[0007] The multi-scale layered structure is composed of at least three of the following: micron-sized equiaxed aluminum grains, a core-shell structure consisting of α, β titanium grains and an element diffusion layer, a submicron-sized cellular structure, a nano-Al3Ti primary phase, and a TiAl nanophase.

[0008] As a preferred embodiment, the composite material comprises Al grains, (α+β)Ti grains, an element diffusion layer, a cellular substructure, Al3Ti nucleation particles, and a TiAl high-temperature phase. Both the horizontal and structural planes of the composite material are composed of equiaxed Al grains. The cellular substructure present on the structural planes of the composite material exhibits equiaxed characteristics. Preferably, the equiaxed Al grain size is 0.5–6 μm, the (α+β)Ti grain size is 0.2–3 μm, the element diffusion layer thickness is 0.2–5 μm, the cellular substructure size is 100–500 nm, the Al3Ti nucleation particles size is 50–100 nm, and the TiAl phase size is 10–80 nm.

[0009] As a preferred embodiment, the aluminum alloy matrix is ​​selected from at least one of Al-Li, Al-Fe, Al-Ni, Al-Ce, Al-Cu, Al-Si, Al-Mg, Al-Mg-Si, and Al-Mg-Zn, and the titanium alloy includes at least one of α-Ti alloy, β-Ti alloy, α+β type Ti alloy, and Ti-based intermetallic compound. More preferably, the aluminum alloy is Al-5Mg-2Si-3Zn, and the titanium alloy is α+β type Ti6Al4V alloy.

[0010] As a preferred embodiment of the additive manufacturing high-performance aluminum-titanium metal composite material and its preparation method according to the present invention, the composite material has a yield strength ≥ 450 MPa, tensile strength ≥ 500 MPa, elongation ≥ 12%, and isotropy of 0.9 ~ 1. After optimization, the composite material has a yield strength ≥ 550 MPa, tensile strength ≥ 600 MPa, elongation ≥ 20%, and isotropy of 1.

[0011] To solve the above-mentioned technical problems, according to another aspect of the present invention, the present invention provides the following technical solution:

[0012] A high-performance aluminum-titanium metal composite material for additive manufacturing and its preparation method, comprising the following steps:

[0013] (1) Aluminum alloy spherical powder and titanium alloy spherical powder are mixed evenly to obtain uniform composite material powder. Preferably, aluminum alloy spherical powder for laser powder bed melting is mixed with titanium alloy spherical powder to obtain composite material powder;

[0014] (2) The composite material powder described in step (1) is printed into a component using a laser powder bed melting process.

[0015] As a preferred embodiment of the additive manufacturing high-performance aluminum-titanium metal composite material and its preparation method described in this invention, in step (1), the particle size of the aluminum alloy powder is 10~79 μm; the particle size of the titanium alloy spherical powder is 15~53 μm.

[0016] As a preferred embodiment of the additive manufacturing high-performance aluminum-titanium metal composite material and its preparation method described in this invention, in step (1), a uniformly distributed composite metal powder is obtained by ultrasonic-assisted water bath stirring. Preferably, the vibration frequency is 20-40 kHz, the stirrer speed is 600-800 r / min, the water bath temperature is 100-150℃, and the mixing time is 20-60 min.

[0017] Furthermore, in step (2), anhydrous ethanol is added as a mixing medium during the ultrasonic-assisted water bath stirring process.

[0018] As a preferred embodiment of the additive manufacturing high-performance aluminum-titanium metal composite material and its preparation method according to the present invention, in step S2, the parameters of the laser additive manufacturing process are: laser energy volume density of 150~280 J / mm². 3 The optical path scanning path is in the form of a checkerboard pattern, and the substrate preheating temperature is 100 ~ 150 ℃.

[0019] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0020] (1) This invention uses micron-sized titanium alloy spherical powder as a substitute for nano-ceramic particles. Compared with nano-ceramic particles, the smaller the specific surface area of ​​micron-sized titanium alloy spherical powder, the smaller its surface energy, and the less likely it is to agglomerate during the mixing process. In terms of preparation method, compared with composite powder preparation processes such as electrostatic adsorption, in-situ synthesis and ball milling, the ultrasonic-assisted water bath stirring method of this invention is low in cost, simple in process, and can achieve uniform mixing of powders.

[0021] (2) The titanium alloy powder added in this invention has better effects than traditional nano-ceramic additives. Ti element has a large growth limiting factor, which increases the undercooling during solidification and thus refines Al aluminum grains; in addition, the primary Al3Ti phase generated in situ acts as nucleation sites at the solidification front, promoting the transformation of columnar grains to equiaxed grains; the titanium alloy exists in a core-shell structure of matrix + element transition layer, which greatly improves the coordinated deformation ability of composite materials; a high-density nano-TiAl precipitate phase is formed at the intersection of diffused Al and Ti elements in the transition layer.

[0022] (3) The aluminum alloy-titanium metal composite material of the present invention forms a multi-scale layered structure during the rapid solidification process of laser additive manufacturing, including equiaxed Al grains, a core-shell structure (composed of α+β Ti grains and element diffusion layers), a cellular substructure, an Al3Ti primary phase, and nano-TiAl precipitates. This multi-scale characteristic structure can improve the interaction with dislocations. Specifically, the fine equiaxed grains and cellular substructure can simultaneously improve strength and plasticity. This is because fine grains not only provide high-density grain boundaries to block dislocations, thus providing a strengthening effect, but also allow plastic deformation to be dispersed within more grains when subjected to external forces, resulting in more uniform plastic deformation. The core-shell structure consists of a soft "shell" and a hard "core". The soft transition layer plays a role in deformation coordination, while the hard "core" generally plays a role in blocking dislocations, thus achieving the purpose of strong plasticity coordination. The high-density TiAl nano-precipitates provide a strong precipitation strengthening effect. The synergistic effect of the three achieves a high-strength and high-toughness metal composite material. This provides a new solution for preparing high-performance aluminum-based composite materials for laser additive manufacturing. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following descriptions of the embodiments will explain the technical solutions used.

[0024] The accompanying drawings are briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0025] Figure 1 The image shows the backscattered electron pattern of the mixed powder and the surface morphology of the printed sample in Example 1.

[0026] Figure 2 This is a grain diagram of the aluminum alloy in Comparative Example 1;

[0027] Figure 3 The multi-scale layered tissue prepared in Example 1;

[0028] Figure 4 This is the element transition layer described in Example 1;

[0029] Figure 5 The complex sample formed from the composite material obtained in Example 1;

[0030] from Figure 1 As can be seen in (a), the aluminum alloy and titanium alloy powders in Example 1 are mixed evenly, and Figure 1 (b) shows a highly dense, metallurgically sound laser-formed surface. The darker areas in the morphology image are aluminum alloy, and the lighter areas are titanium alloy.

[0031] from Figure 2 It can be seen that the aluminum grains in Comparative Example 1 are coarse columnar grains.

[0032] from Figure 3 As can be seen from Example 1, the composite material exhibits a typical multi-scale layered structure, mainly composed of (a) micrometer-scale equiaxed aluminum grains, (b) submicrometer-scale cellular substructures and nanoscale primary Al3Ti phases, (c) micrometer-scale core-shell structures, and (d) TiAl nanoprecipitates. The formation of equiaxed aluminum grains on the structural planes is primarily due to the synergistic effect of Ti elements and the primary Al3Ti phase. This results in both horizontal and structural plane grains exhibiting equiaxed characteristics, thereby achieving isotropic properties.

[0033] from Figure 4 It can be seen that in Example 1, the "core" of the core-shell structure is composed of Ti grains, and the "shell" is generated by the elemental transition region. Among them, the elemental transition region contains nanoscale TiAl precipitates.

[0034] from Figure 5 It can be seen that the aluminum-titanium metal composite components formed by laser powder bed melting technology have good formability and excellent surface quality. Detailed Implementation

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0036] This invention proposes a high-performance aluminum-titanium metal composite material for additive manufacturing and its preparation method. The prepared aluminum-titanium metal composite material achieves an excellent combination of strength and plasticity through a multi-scale layered structure and eliminates the anisotropy of the material. The microstructure and properties are regulated by adding titanium alloy powder, providing a new method for preparing high-performance laser powder bed melting aluminum-based composite materials. In this invention, micron-sized aluminum alloy powder and micron-sized titanium alloy powder are uniformly mixed using an ultrasonic-assisted water bath stirring method. During solidification, the micron-sized titanium alloy powder promotes the formation of a multi-scale layered structure with equiaxed crystals, core-shell structures, cellular substructures, and nano-precipitates, thereby improving the strength and plasticity of the material and achieving isotropic mechanical properties.

[0037] According to one aspect of the present invention, the present invention provides the following technical solution:

[0038] A high-performance aluminum alloy-titanium metal composite material for additive manufacturing, wherein the high-performance composite material comprises a multi-scale layered structure, specifically, the multi-scale layered structure is composed of at least three of the following: micron-sized equiaxed aluminum grains, a core-shell structure composed of α, β titanium grains and an element diffusion layer, a submicron-sized cellular structure, a nano-Al3Ti primary phase, and a TiAl nano-phase.

[0039] Preferably, the composite material comprises laser powder bed fused aluminum alloy and titanium alloy. Preferably, the mass fraction of the titanium alloy is 2 to 15 wt.%, which ensures uniform mixing of the titanium alloy and the aluminum alloy. Specifically, the mass fraction of the titanium alloy is, for example, but not limited to, any one or any two of 2 wt.%, 3 wt.%, 4 wt.%, 5 wt.%, 6 wt.%, 7 wt.%, 8 wt.%, 9 wt.%, 10 wt.%, 11 wt.%, 12 wt.%, 13 wt.%, 14 wt.%, and 15 wt.%.

[0040] More preferably, the aluminum alloy includes at least one of Al-Li, Al-Fe, Al-Ni, Al-Ce, Al-Cu, Al-Si, Al-Mg, Al-Mg-Si, and Al-Mg-Zn-based alloys, and the titanium alloy includes at least one of α-Ti alloy, β-Ti alloy, α+β Ti alloy, and Ti-based intermetallic compounds. Further preferably, the aluminum alloy is, for example, but not limited to, Al-Li, Al-Li-Mg, Al-Li-Ag, Al-Li-Cu, Al-Li-Zn, Al-Li-Cu-Zn, Al-Fe-Ce, Al-Fe-Si, Al-Ni-Cu, Al-Ce-Cu, Al-Fe-Ni-Ce, Al- Cu, Al-Cu-Mg, Al-Cu-Mg-Si, Al-Cu-Mg-Mn, Al-Si-Mg, Al-Si-Cu, Al-Si-Mg-Zn, Al-Mg, Al-Mg-Si, Al-Mg-Si-Zn, Al-Mg-Si-Cu, Al-Mg-Si-Zn-Cu, Al-Z The titanium alloy can be any one of n-Mg-Cu, Al-Zn-Mg-Si, and Al-Zn-Mg-Cu-Si, and can be, for example, but not limited to, α titanium alloy, β titanium alloy, (α+β) type titanium alloy, titanium-based intermetallic compound, α titanium alloy + β titanium alloy, α titanium alloy + (α+β) type titanium alloy, α titanium alloy + titanium-based intermetallic compound, β titanium alloy + (α+β) type titanium alloy, β titanium alloy + titanium-based intermetallic compound, (α+β) type titanium alloy + titanium-based intermetallic compound, α titanium alloy + β titanium alloy + (α+β) type titanium alloy, β titanium alloy + (α+β) type titanium alloy + titanium-based intermetallic compound, and α titanium alloy + β titanium alloy + (α+β) type titanium alloy + titanium-based intermetallic compound.

[0041] The composite material has a yield strength ≥ 450 MPa, tensile strength ≥ 500 MPa, elongation ≥ 12%, and isotropic ratio of 0.9 ~ 1. After optimization, the composite material has a yield strength ≥ 550 MPa, tensile strength ≥ 600 MPa, elongation ≥ 20%, and isotropic ratio of 1.

[0042] This invention also provides a method for preparing high-performance aluminum-titanium metal composite materials by additive manufacturing, comprising the following steps:

[0043] (1) A composite material powder is obtained by mixing aluminum alloy spherical powder and titanium alloy spherical powder for laser powder bed melting;

[0044] (2) The composite material powder described in step (1) is printed to form a component using a laser powder bed melting process.

[0045] Preferably, in step S1, when using ultrasonic-assisted water bath stirring, the vibration frequency is 20-40 kHz, the stirrer speed is 600-800 r / min, the water bath temperature is 100-150 ℃, and the mixing time is 20-60 min.

[0046] Specifically, the vibration frequency can be, for example, but not limited to, any one or any two of 20 kHz, 25 kHz, 30 kHz, 35 kHz, and 40 kHz; the rotational speed can be, for example, but not limited to, any one or any two of 600 r / min, 650 r / min, 700 r / min, 750 r / min, and 800 r / min; the water bath temperature can be, for example, but not limited to, any one or any two of 100 ℃, 110 ℃, 120 ℃, 130 ℃, 140 ℃, and 150 ℃; the mixing time can be, for example, but not limited to, any one or any two of 20 min, 30 min, 40 min, 50 min, and 60 min; the particle size of the aluminum alloy powder is 10 ~ 79 μm; and the particle size of the titanium alloy spherical powder is 15 ~ 53 μm. Specifically, the particle size of the aluminum alloy powder can be, for example, but not limited to, any two of 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, and 79 μm; the particle size of the titanium alloy can be, for example, but not limited to, any two of 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 45 μm, 50 μm, and 53 μm.

[0047] In step S2, the parameters of the laser additive manufacturing process are: laser energy volume density of 150 ~ 280 J / mm². 3 The optical path scanning path is in a checkerboard pattern, and the substrate preheating temperature is 100~150℃. The laser energy volume density can be, for example, but not limited to, 150 J / mm². 3 170 J / mm 3 190 J / mm 3 210 J / mm 3 230 J / mm 3 250 J / mm 3 270 J / mm 3 280 J / mm 3 The substrate preheating temperature can be, for example, but not limited to, any one or any two of 100 ℃, 110 ℃, 120 ℃, 130 ℃, 140 ℃, 150 ℃.

[0048] The present invention will be further described below with reference to specific embodiments and accompanying drawings.

[0049] Example 1

[0050] A high-performance aluminum-titanium metal composite material for additive manufacturing, the composite material comprising Al-5Mg-2Si-3Zn aluminum alloy (wt%) and (α+β) type Ti6Al4V titanium alloy with a mass fraction of 6 wt.%;

[0051] The preparation method of the composite material includes the following steps:

[0052] (1) The composite material powder was obtained by ultrasonic-assisted water bath stirring of aluminum alloy spherical powder and titanium alloy spherical powder in the above proportion. The vibration frequency during mixing was 30 KHz, the stirring speed was 680 r / min, the water bath temperature was 120 ℃, the mixing time was 35 min, and the mixing medium was volatile anhydrous ethanol. The aluminum alloy powder was Al-5Mg-2Si-3Zn with a particle size of 10 ~ 79 μm. The (α+β) type Ti6Al4V titanium alloy powder had a particle size of 15 ~ 53 μm.

[0053] (2) The composite material powder described in step (1) is used to print components using a laser powder bed melting process. The process parameters are: laser energy volume density of 175 J / mm². 3 The optical path scanning path is in the form of a checkerboard pattern, and the substrate preheating temperature is 120℃.

[0054] Experimental results show that the composite material achieves a density of 99.9%, and the columnar grains on the structural plane are transformed into fine equiaxed grains. A multi-scale layered structure is formed, consisting of micron-scale equiaxed aluminum grains, a core-shell structure composed of micron-scale α and β titanium grains and an elemental diffusion layer, a submicron cellular structure, and nano-Al3Ti primary phase and TiAl nanophase. At this point, the composite material exhibits a yield strength of 550 MPa, a tensile strength of 600 MPa, an elongation of 20%, and an isotropy of 1.

[0055] Example 2

[0056] The difference between Example 2 and Example 1 lies in the type of aluminum alloy:

[0057] Example 2 uses A6061 aluminum alloy powder and (α+β) type Ti6Al4V titanium alloy powder with a mass fraction of 6 wt.%. The composite material has a density of 99.5%, a yield strength of 516 MPa, a tensile strength of 540 MPa, an elongation of 18.8%, and an isotropic rate of 1.

[0058] Example 3

[0059] The difference between Example 3 and Example 1 lies in the type of titanium alloy:

[0060] Example 3 uses Al-5Mg-2Si-3Zn alloy powder (wt%) and α-type CP-Ti titanium alloy powder with a mass fraction of 6 wt.%. The composite material has a density of 99.7%, a yield strength of 531 MPa, a tensile strength of 608 MPa, an elongation of 14.7%, and an isotropic rate of 1.

[0061] Example 4

[0062] The difference between Example 4 and Example 1 lies in the content of titanium alloy powder:

[0063] Example 4 uses Ti6Al4V titanium alloy powder with a mass fraction of 2 wt.%. The composite material has a density of 99.2%, a yield strength of 450 MPa, a tensile strength of 500 MPa, an elongation of 14.3%, and an isotropic rate of 0.90.

[0064] Example 5

[0065] The difference between Example 5 and Example 1 lies in the content of titanium alloy powder:

[0066] Example 5 uses Ti6Al4V titanium alloy powder with a mass fraction of 15 wt.%. The composite material has a density of 99.6%, a yield strength of 582 MPa, a tensile strength of 644 MPa, an elongation of 12.0%, and an isotropic rate of 0.97.

[0067] Example 6

[0068] The difference between Example 6 and Example 1 lies in the laser powder bed melting process parameters:

[0069] The laser energy volume density of the laser powder bed melting in Example 6 was 150 J / mm². 3 The substrate was preheated to 100 ℃, the density of the composite material reached 99.1%, the yield strength of the composite material was 481 MPa, the tensile strength was 573 MPa, the elongation was 15.3%, and the isotropy was 0.95.

[0070] Example 7

[0071] The difference between Example 7 and Example 1 lies in the laser powder bed melting process parameters:

[0072] The laser energy volume density of the laser powder bed melting in Example 7 was 220 J / mm². 3The substrate was preheated to 150 ℃, the density of the composite material reached 99.8%, the yield strength of the composite material was 469 MPa, the tensile strength was 512 MPa, the elongation was 19.4%, and the isotropic rate was 0.96.

[0073] Example 8

[0074] The difference between Example 8 and Example 1 lies in the different mixing conditions:

[0075] In Example 8, the vibration frequency during mixing was 20 kHz, the stirrer speed was 600 r / min, the water bath temperature was 100 ℃, the mixing time was 20 min, and the mixing medium was volatile anhydrous ethanol. The composite material achieved a density of 99.0%, a yield strength of 520 MPa, a tensile strength of 566 MPa, an elongation of 12.6%, and an isotropy of 0.94.

[0076] Comparative Example 1

[0077] The difference between Comparative Example 1 and Example 1 is that it does not include titanium alloy powder.

[0078] Experimental results show that the composite material has a density of 96.7%, a yield strength of 406 MPa, a tensile strength of 454 MPa, an elongation of 6.3%, and an isotropic rate of 0.53.

[0079] Comparative Example 2

[0080] The difference between Comparative Example 2 and Example 1 is that Comparative Example 2 includes 1 wt.% titanium alloy powder.

[0081] Experimental results show that the composite material has a density of 98.7%, a yield strength of 430 MPa, a tensile strength of 480 MPa, an elongation of 8.5%, and an isotropic rate of 0.80.

[0082] Comparative Example 3

[0083] The difference between Comparative Example 3 and Example 1 is that Comparative Example 3 includes 25 wt.% titanium alloy powder.

[0084] Experimental results show that the composite material has a density of 95.7%, a yield strength of 480 MPa, a tensile strength of 564 MPa, an elongation of 1.3%, and an isotropic rate of 0.66.

[0085] Comparative Example 4

[0086] The difference between Comparative Example 4 and Example 1 lies in the laser powder bed melting process parameters:

[0087] The laser energy volume density of the laser powder bed melting in Comparative Example 4 was 300 J / mm². 3 The substrate is formed without preheating.

[0088] Experimental results show that the composite material has a density of 98.2%, a yield strength of 435 MPa, a tensile strength of 500 MPa, an elongation of 3.2%, and an isotropic rate of 0.48.

[0089] Comparative Example 5

[0090] The difference between Comparative Example 5 and Example 1 lies in the laser powder bed melting process parameters:

[0091] The laser energy volume density of the laser powder bed melting in Comparative Example 5 was 80 J / mm². 3 The preheating temperature of the substrate is 300℃.

[0092] Experimental results show that the composite material has a density of 95.6%, a yield strength of 238 MPa, a tensile strength of 304 MPa, an elongation of 10.3%, and an isotropic rate of 0.75.

[0093] Comparative Example 6

[0094] The difference between Comparative Example 6 and Example 1 lies in the different mixing methods:

[0095] The mixing method in Comparative Example 6 was to use a V-type powder mixer for powder mixing, and the mixing time was 1 hour.

[0096] Experimental results show that the composite material has a density of 96.5%, a yield strength of 377 MPa, a tensile strength of 485 MPa, an elongation of 11.5%, and an isotropic rate of 0.87.

[0097] All the above samples were tested for strength and Vickers hardness under the same conditions according to national standards. The experimental results of each sample are shown in Table 1.

[0098]

[0099] The test results shown in Table 1 demonstrate that the present invention, by incorporating titanium alloy powder into the aluminum alloy matrix to promote the equiaxation of columnar aluminum grains and the formation of a multi-scale layered structure, enables the laser powder bed melting of metal composite materials to achieve high density and excellent strength. Furthermore, by adjusting the powder bed melting printing parameters, an excellent strength-ductility combination can be achieved in the aluminum alloy.

[0100] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A high-performance aluminum-titanium metal composite material for additive manufacturing, characterized in that: The metal composite material is made by 3D printing using aluminum alloy powder and titanium alloy powder as raw materials. The density of the metal composite material is greater than 99%. In the raw materials, the mass fraction of titanium alloy is 2 to 15 wt.%. The metal composite material contains a multi-scale layered structure. The multi-scale layered structure is composed of at least three of the following: micron-sized equiaxed aluminum grains, a core-shell structure consisting of α, β titanium grains and an element diffusion layer, a submicron-sized cellular structure, a nano-Al3Ti primary phase, and a TiAl nano-phase. The equiaxed Al grain size is 0.5~6 μm, the (α+β)Ti grain size is 0.2~3 μm, the element diffusion layer thickness is 0.2 μm~5 μm, the size of the cellular substructure is 100~500 nm, the Al3Ti nucleation particles are 50~100 nm, and the TiAl phase size is 10~80 nm. The high-performance aluminum-titanium metal composite material is prepared by the following steps: S1. Mix aluminum alloy spherical powder and titanium alloy spherical powder evenly to obtain uniform composite material powder; S2. The uniform composite material powder described in step S1 is used to print components using a laser powder bed melting process; the laser powder bed melting process parameters are: laser energy and volume density of 150 ~ 280 J / mm². 3 The optical path scanning path is in the form of a checkerboard pattern, and the substrate preheating temperature is 100~150℃; In S1, aluminum alloy spherical powder and titanium alloy spherical powder are mixed using an ultrasonic-assisted water bath stirring method to obtain a uniform composite material powder. When mixing powder using the ultrasonic-assisted water bath stirring method, the vibration frequency is controlled at 20-40 kHz, the stirrer speed is 600-800 r / min, the water bath temperature is 100-150℃, the mixing time is 20-60 min, and the mixing medium is volatile anhydrous ethanol.

2. The additive manufacturing high-performance aluminum-titanium metal composite material according to claim 1, characterized in that: The 3D printing includes laser powder bed fusion printing, wherein the titanium alloy has a mass fraction of 2 to 7 wt.% and the aluminum alloy has a mass fraction of 93 to 98 wt.%; the aluminum alloy matrix is ​​selected from at least one of Al-Li, Al-Fe, Al-Ni, Al-Ce, Al-Cu, Al-Si, Al-Mg, Al-Mg-Si and Al-Mg-Zn based alloys, and the titanium alloy includes at least one of α-Ti alloy, β-Ti alloy, α+β Ti alloy and Ti-based intermetallic compounds.

3. The additive manufacturing high-performance aluminum-titanium metal composite material according to claim 2, characterized in that: The resulting composite material has a yield strength ≥ 450 MPa, tensile strength ≥ 500 MPa, elongation ≥ 12%, and isotropic ratio of 0.9~1.

4. The additive manufacturing high-performance aluminum-titanium metal composite material according to claim 1, characterized in that: In step S1, the ultrasonic vibration frequency is 30-40 kHz, the stirrer speed is 600-700 r / min, the water bath temperature is 100-130℃, the mixing time is 30-40 min, and the mixing medium is volatile anhydrous ethanol.

5. The additive manufacturing high-performance aluminum-titanium metal composite material according to claim 1, characterized in that: In step S1, the particle size of the aluminum alloy spherical powder is 10~79 μm; the particle size of the titanium alloy spherical powder is 15~53 μm.

6. The additive manufacturing high-performance aluminum-titanium metal composite material according to claim 5, characterized in that: In step S2, the laser energy and volume density of the laser powder bed melting process are 150~180 J / mm². 3 The optical path scanning path is in the form of a checkerboard pattern, and the substrate preheating temperature is 100 ~ 125℃.

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