High-performance aluminum alloy for additive manufacturing and method for producing the same

Abstract

The present application is directed to the cracking problem of aluminum alloy additive manufacturing, and provides a component design idea and preparation method of high-performance aluminum alloy for additive manufacturing, enriching the aluminum alloy material system of additive manufacturing. In the 2000 or 7000 series high-strength aluminum alloy, the cracking sensitivity is reduced by using appropriate Y element and Sc, Zr, Ti and other transition metal elements, the cracking problem of additive manufacturing is solved, and the additive manufacturing forming performance is improved, so that it is more suitable for additive manufacturing. The high-performance aluminum alloy for additive manufacturing provided by the present application shows good additive manufacturing forming performance, and can prepare crack-free aluminum alloy in a wide range of process parameters, and has excellent comprehensive mechanical properties. The component design of the present application is reasonable, the preparation process is simple, the performance of the obtained product is excellent, the additive manufacturing process parameter range is large, and it is convenient for large-scale industrial production and practical application.

Description

Technical Field

[0001] This invention relates to a high-performance aluminum alloy for additive manufacturing and its preparation method, belonging to the fields of aluminum alloys and additive manufacturing. Background Technology

[0002] Aluminum alloys possess excellent mechanical properties and high specific strength, making them widely used in aerospace structural components. Additive manufacturing technology offers high design freedom and has unique advantages in fabricating complex-shaped aluminum alloy components. However, additive manufacturing involves high cooling rates and temperature gradients. Traditional high-strength aluminum alloys designed based on casting-deformation processes are prone to additive manufacturing cracking, making forming difficult and hindering the achievement of ideal microstructure and mechanical properties.

[0003] Therefore, there is a need to develop high-performance aluminum alloys suitable for additive manufacturing processes. LI et al. [LI, et al. Laser powder bed fusion of nano-titania modified 2219 aluminum alloy with superior mechanical properties at both room and elevated temperatures: The significant impact of solid[J]. Additive Manufacturing, 2022, 60: 103296] disclosed a TiO2 modified 2219 aluminum alloy. The alloy prepared by laser powder bed fusion (LPBF) is almost completely dense, with a yield strength of 173 MPa, a tensile strength of 366 MPa, and an elongation of 11.1%. CHEN et al. [CHEN et al. Microstructure characterization and mechanical properties of crack-free Al-Cu-Mg-Y alloy fabricated by laser powder bed fusion, Additive Manufacturing, 2022, 58:103006] prepared a 2024 / Y hybrid powder by adding 1.5 wt% Y to 2024 aluminum alloy powder, and then prepared a novel crack-free high-strength Al-Cu-Mg-Y alloy by LPBF. The yield strength of the printed sample was 206 MPa, the tensile strength was 259 MPa, and the elongation was 3%. ZHANG et al. [ZHANGH, et al. Effect of Zirconium addition on crack, microstructure and mechanical behavior of selective laser melted Al-Cu-Mg alloy[J].ScriptaMaterialia,2017,134:6-10] disclosed a Zr (2wt%) modified Al-Cu-Mg alloy, in which the elongation of the Al-Cu-Mg-Zr alloy prepared by LPBF was reduced by 55% compared with that of the Al-Cu-Mg alloy.ZHANG et al. [ZHANG J, et al. A novel crack-free Ti-modified Al-Cu-Mg alloy designed for selective laser melting[J]. Additive Manufacturing,2021,38:101829] disclosed a novel crack-free Ti (1.5wt%) modified Al-Cu-Mg alloy for LPBF, with a yield strength of 293 MPa, a tensile strength of 426 MPa, and an elongation of 9.1% in the printed state.

[0004] This invention proposes a composition design concept for high-performance aluminum alloys for additive manufacturing. By combining Y element and transition metal elements, the additive manufacturing forming performance of 2000 or 7000 series aluminum alloys is improved, solving the cracking problem in additive manufacturing, broadening the forming process window, and designing a high-performance aluminum alloy suitable for additive manufacturing. Summary of the Invention

[0005] To address the issues of poor formability and processability in aluminum alloy additive manufacturing, this invention provides a high-performance aluminum alloy for additive manufacturing and its preparation method. The high-performance aluminum alloy provided by this invention can adapt to the high temperature gradients and cooling rates of additive manufacturing processes, will not crack during forming, and the products prepared from it possess excellent mechanical properties.

[0006] To achieve the above-mentioned objective, the present invention provides a high-performance aluminum alloy for additive manufacturing, wherein the high-performance aluminum alloy is a 2000 or 7000 series aluminum alloy in which rare earth Y and transition metal elements are introduced simultaneously.

[0007] The transition metal elements are selected from at least one of the elements Sc, Zr, and Ti.

[0008] This invention provides a method for preparing a high-performance aluminum alloy for additive manufacturing. The high-performance aluminum alloy is obtained by additive manufacturing using aluminum alloy powder as raw material to produce a crack-free aluminum alloy in a printed state.

[0009] This invention discloses a high-performance aluminum alloy for additive manufacturing and its preparation method, wherein the aluminum alloy powder preferably has the following composition by mass percentage:

[0010] Cu: 4.0–4.9%; Y: 1.0–3.0%; Mg: 0.4–1.8%; Si: 0.4–1.2%; Mn: 0.4–1.0%; Fe: <0.5%; Transition metals: 0.6–1.5%; Balance: Al.

[0011] The aluminum alloy powder was prepared by gas atomization.

[0012] Preferably, the mass ratio of Y to transition metals is 1.2–1.4:0.8–0.6.

[0013] This invention discloses a method for preparing a high-performance aluminum alloy for additive manufacturing, wherein the aluminum alloy powder is placed in a vacuum drying oven for drying treatment at a temperature of 80-120°C for a treatment time of 2-12 hours.

[0014] This invention discloses a high-performance aluminum alloy for additive manufacturing and its preparation method. The additive manufacturing technology is selected from one of laser powder bed melting, electron beam melting, or coaxial powder feeding laser forming technology, preferably laser powder bed melting.

[0015] This invention discloses a method for preparing a high-performance aluminum alloy for additive manufacturing, wherein the substrate is preheated before additive manufacturing at a temperature of 80–200°C.

[0016] The laser power of laser additive manufacturing is 200-400W, the scanning speed is 300-1500mm / s, the overlap spacing is 80-150μm, the layer thickness is 30-50μm, and the interlayer rotation angle is 65-70°.

[0017] The additive manufacturing process employs a protective atmosphere, controlling the oxygen content in the forming chamber to be less than 0.1 wt.%.

[0018] The protective gas should be one of nitrogen, argon, or helium, or a mixture of nitrogen, argon, and helium, with a purity exceeding 99.99 wt% and an oxygen content of less than 0.0001 wt%.

[0019] This invention discloses a high-performance aluminum alloy for additive manufacturing and its preparation method. When the prepared printed product is an Al-4.2Cu-0.5Mg-1.1Si-0.7Mn-1.3Y-0.7Zr (wt.%) alloy, its yield strength is greater than or equal to 318MPa, its tensile strength is greater than or equal to 418MPa, its elongation is greater than 13.8%, and it is free of crack defects.

[0020] Advantages and positive effects of the present invention

[0021] This invention proposes a compositional design approach for high-performance aluminum alloys used in additive manufacturing, resulting in high-strength aluminum alloys suitable for additive manufacturing. By combining yttrium (γ) with transition metal elements, the solidification behavior of the aluminum alloy is improved, the grain size is refined, crack susceptibility is reduced, and additive manufacturing cracks are eliminated, thereby significantly improving the additive manufacturing forming performance of the aluminum alloy.

[0022] (1) This invention proposes a composition design concept for high-performance aluminum alloys for additive manufacturing. Y element and transition metal elements such as Sc, Zr, and Ti are added to 2000 or 7000 series aluminum alloys to synergistically improve the solidification behavior of aluminum alloys, significantly reduce the cracking sensitivity of additive manufacturing, and significantly improve the forming performance of additive manufacturing, making it more suitable for additive manufacturing and capable of preparing completely crack-free high-strength aluminum alloys.

[0023] (2) This invention proposes a composition design concept for high-performance aluminum alloys for additive manufacturing. Under the synergistic effect of Y and transition metal elements, a strengthening phase is introduced to significantly strengthen the aluminum alloy, further improve the crack resistance of the alloy, and reduce the crack sensitivity of the aluminum alloy in additive manufacturing.

[0024] (3) The present invention proposes a composition design concept for high-performance aluminum alloys for additive manufacturing, which can obtain crack-free high-performance aluminum alloys in multiple alloy systems and using a variety of additive manufacturing technologies within a large parameter range.

[0025] (4) This invention is the first to realize additive manufacturing of high-performance 2A14 aluminum alloy, which can prepare crack-free samples within a wide range of process parameters, and the prepared samples have excellent mechanical properties in the printing state. Attached Figure Description

[0026] Figure 1 These are scanning electron microscope images of the 2A14YZr aluminum alloy powder in Example 1;

[0027] Figure 2 These are metallographic photographs of the 2A14YZr aluminum alloy prepared by LPBF in Example 1;

[0028] Figure 3 The stress-strain curves are obtained from room temperature tensile tests of the 2A14YZr aluminum alloy prepared by LPBF in Example 1.

[0029] Figure 4 This is an OM image of the longitudinal section of the 2A14YZr aluminum alloy prepared by LPBF in Example 2;

[0030] Figure 5 This is a SEM image of the longitudinal section of the 2A14YZr aluminum alloy prepared by LPBF in Example 2;

[0031] Figure 6 The stress-strain curves are obtained from room temperature tensile tests of the 2A14YZr aluminum alloy specimen prepared by LPBF in Example 2.

[0032] Figure 7 This is an OM image of the longitudinal section of 2A14 aluminum alloy prepared by LPBF in Comparative Example 1;

[0033] Figure 8This is an OM image of the longitudinal section of the 2A14Y aluminum alloy prepared by LPBF in Comparative Example 2. Detailed Implementation

[0034] Example 1:

[0035] 2A14 aluminum alloy was selected as the alloy matrix, and Y and Zr modified 2A14 (2A14YZr) aluminum alloy powder was prepared by argon atomization. The specific composition is as follows (wt.%):

[0036] Cu 4.2%; Y 1.3%; Zr 0.7%; Mg 0.5%; Si 1.1%; Mn 0.7%; Fe 0.2%; balance Al; alloy powder with a particle size of 10-53 μm was obtained after vibrating sieving for laser powder bed melting (LPBF) forming; Figure 1 The images show scanning electron microscope (SEM) images of the 2A14YZr aluminum alloy powder used in additive manufacturing. The vast majority of the powder morphologies exhibit a uniform spherical shape.

[0037] Using 2A14YZr aluminum alloy powder as raw material, LPBF additive manufacturing was employed. The LPBF process parameters were set as follows: laser power 280W, scanning speed 300mm / s, overlap spacing 100μm, layer thickness 30μm, interlayer rotation angle 67°, oxygen content in the forming chamber controlled below 800ppm, and the printing substrate preheated to 120℃. Before LPBF forming, the aluminum alloy powder was dried in a vacuum drying oven at 100℃ for 8 hours. 2A14YZr aluminum alloy was prepared using the above process parameters.

[0038] Figure 2 The image shown is a metallographic photograph of 2A14YZr aluminum alloy prepared by LPBF. No cracks or defects were found in the 2A14YZr alloy, indicating that the designed aluminum alloy is suitable for additive manufacturing.

[0039] The prepared alloy sample was subjected to tensile testing at room temperature, and the resulting stress-strain curves are shown below. Figure 3 As shown. By Figure 3 It can be seen that the 2A14YZr aluminum alloy prepared by LPBF in this invention has a yield strength of 318MPa, a tensile strength of up to 418MPa, and an elongation of 13.8%.

[0040] The results show that the designed 2A14YZr aluminum alloy exhibits good additive manufacturing performance, and the samples prepared by LPBF have excellent mechanical properties, making them suitable for additive manufacturing.

[0041] Example 2:

[0042] Using 2A14YZr aluminum alloy powder from Example 1 as raw material, LPBF additive manufacturing was employed. The LPBF process parameters were set as follows: laser power 240–360 W, scanning speed 500–1300 mm / s, overlap spacing 100 μm, layer thickness 30 μm, interlayer rotation angle 67°, oxygen content in the forming chamber controlled below 800 ppm, and the printing substrate preheated to 150°C. Before LPBF forming, the aluminum alloy powder was dried in a vacuum drying oven at 100°C for 8 hours. 2A14YZr aluminum alloy was prepared using the above process parameters.

[0043] The obtained metallographic photographs of a batch of printed 2A14YZr aluminum alloys are as follows: Figure 4 As shown, no cracks occurred.

[0044] The 2A14YZr aluminum alloy prepared under the conditions of laser power of 360W and scanning speed of 700mm / s had the fewest defects and a relative density of 99.54%. Its longitudinal section SEM image is shown below. Figure 5 As shown in the figure, the alloy exhibits no cracks or defects, only a small amount of porosity. The alloy sample prepared under laser power of 360W and scanning speed of 700mm / s was subjected to tensile testing at room temperature, and the resulting stress-strain curves are shown below. Figure 6 As shown. By Figure 6 It can be seen that the 2A14YZr aluminum alloy prepared by LPBF in this invention has a yield strength of 345MPa, a tensile strength of up to 421MPa, and an elongation of 15.1%.

[0045] The results show that the designed 2A14YZr aluminum alloy can be used to prepare crack-free samples within a wide parameter range. The printed samples exhibit excellent comprehensive mechanical properties and are suitable for additive manufacturing.

[0046] Example 3:

[0047] Y and Zr modified 2A14 aluminum alloy powder was prepared by argon atomization using 2A14 aluminum alloy as the alloy matrix. The specific composition is as follows (wt.%):

[0048] Cu 4.2%; Y 1.0%; Zr 1.0%; Mg 0.5%; Si 1.1%; Mn 0.7%; Fe 0.2%; balance Al; after vibrating sieving, the alloy powder obtained for laser powder bed melting (LPBF) forming has a particle size of 10-53 μm.

[0049] Y,Zr-modified 2A14 aluminum alloy powder was used as raw material and LPBF additive manufacturing was employed. The LPBF process parameters were set as follows: laser power 360W, scanning speed 900mm / s, overlap spacing 100μm, layer thickness 30μm, interlayer rotation angle 67°, oxygen content in the forming chamber controlled below 800ppm, and the printing substrate preheated to 150℃. Before LPBF forming, the aluminum alloy powder was dried in a vacuum drying oven at 100℃ for 8 hours. Y,Zr-modified 2A14 aluminum alloy was prepared using the above process parameters.

[0050] No cracks or defects were observed in the printed samples. The results indicate that the designed Y and Zr modified 2A14 aluminum alloy exhibits good additive manufacturing performance. The samples prepared by LPBF have excellent mechanical properties and are suitable for additive manufacturing.

[0051] Comparative Example 1:

[0052] 2A14 aluminum alloy was selected, and 2A14 aluminum alloy powder was prepared by argon atomization. The specific composition is as follows (wt.%):

[0053] Cu 4.2%; Mg 0.5%; Si 1.1%; Mn 0.7%; Fe 0.2%; balance Al; alloy powder with a particle size of 10-53 μm was obtained by vibrating sieving for laser powder bed melting.

[0054] Using 2A14 aluminum alloy powder as raw material, LPBF additive manufacturing was employed. The LPBF process parameters were set as follows: laser power 240–360 W, scanning speed 500–1300 mm / s, overlap spacing 100 μm, layer thickness 30 μm, interlayer rotation angle 67°, oxygen content in the forming chamber controlled below 800 ppm, and the printing substrate preheated to 150°C. Before LPBF forming, the aluminum alloy powder was dried in a vacuum drying oven at 120°C for 4 hours. 2A14 aluminum alloy was prepared using the above process parameters.

[0055] Figure 7 The image shows the longitudinal section (XZ) OM image of 2A14 aluminum alloy prepared by LPBF. Severe cracking is observed in all samples, resulting in poor mechanical properties of the prepared 2A14 aluminum alloy; strength and elongation data are unavailable. The results indicate that 2A14 aluminum alloy designed based on a casting-deformation process has high cracking sensitivity and poor additive manufacturing performance, making it unsuitable for additive manufacturing.

[0056] Comparative Example 2:

[0057] 2A14 aluminum alloy was selected as the alloy matrix, and Y-modified 2A14 (2A14Y) aluminum alloy powder was prepared by argon atomization. The specific composition is as follows (wt%):

[0058] Cu 4.2%; Y 1.3%; Mg 0.5%; Si 1.1%; Mn 0.7%; Fe 0.2%; balance Al; after vibrating sieving, the alloy powder obtained for laser powder bed fusion forming has a particle size of 3-85μm, which basically meets the requirements of alloy powder for LPBF.

[0059] Using 2A14Y aluminum alloy powder as raw material, LPBF additive manufacturing was employed. The LPBF process parameters were set as follows: laser power 240–360 W, scanning speed 500–1300 mm / s, overlap spacing 100 μm, layer thickness 30 μm, interlayer rotation angle 67°, oxygen content in the forming chamber controlled below 800 ppm, and the printing substrate preheated to 150°C. Before LPBF forming, the aluminum alloy powder was dried in a vacuum drying oven at 120°C for 4 hours. 2A14Y aluminum alloy was prepared using the above process parameters.

[0060] Figure 8 The image shows the longitudinal section (XZ) OM image of 2A14Y aluminum alloy prepared by LPBF. Cracks are visible in all samples. Some samples are severely cracked. The crack density can be reduced by adjusting the process parameters, but crack-free samples cannot be prepared. The results indicate that Y modification is beneficial to improving the additive manufacturing formability of 2A14Y aluminum alloy. However, the designed 2A14Y aluminum alloy exhibits poor additive manufacturing formability and is not suitable for additive manufacturing.

[0061] The above description is merely a preferred embodiment of the present invention, and is an exemplary embodiment used to illustrate the principle of the present invention. However, the present invention is not limited thereto. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a high-performance aluminum alloy for additive manufacturing, characterized in that: The high-performance aluminum alloy is a 2000 series aluminum alloy in which rare earth Y and transition metal elements are introduced simultaneously; the transition metal elements are selected from at least one of Sc, Zr, and Ti, and the 2000 series aluminum alloy is 2A14 aluminum alloy. The aluminum alloy powder, by mass percentage, has the following composition: Cu: 4.0~4.9%; Y：1.0~3%； Mg: 0.4~1.8%; Si: 0.4~1.2; Mn: 0.4~1.0%; Fe: <0.5%; Transition metals: 0.6~1.5%; Balance Al; Transition metals are selected from at least one of Sc, Zr, and Ti. The aluminum alloy powder is prepared by gas atomization; the high-performance aluminum alloy is obtained by additive manufacturing using aluminum alloy powder as raw material to obtain a crack-free aluminum alloy in a printed state. The substrate is preheated before additive manufacturing, and the preheating temperature is 80~200℃. The laser power of laser additive manufacturing is 200~400W, the scanning speed is 300~1500mm / s, the overlap spacing is 80~150μm, the layer thickness is 30~50μm, and the interlayer rotation angle is 65~70°. The additive manufacturing process employs a protective atmosphere, controlling the oxygen content within the forming chamber to be less than 0.1 wt.%. The protective gas should be one of nitrogen, argon, or helium, or a mixture of nitrogen, argon, and helium, with a purity exceeding 99.99 wt% and an oxygen content of less than 0.0001 wt%. When the prepared printed product is an Al-4.2Cu-0.5Mg-1.1Si-0.7Mn-1.3Y-0.7Zr alloy (mass percentage, wt.%), its yield strength is greater than or equal to 318 MPa, its tensile strength is greater than or equal to 418 MPa, its elongation is greater than 13.8%, and it has no crack defects.

2. The method for preparing a high-performance aluminum alloy for additive manufacturing according to claim 1, characterized in that: The aluminum alloy powder is placed in a vacuum drying oven for drying at a temperature of 80~120°C for 2~12 hours.

3. The method for preparing a high-performance aluminum alloy for additive manufacturing according to claim 1, characterized in that: Additive manufacturing technology is selected from one of laser powder bed melting, electron beam melting, or coaxial powder feeding laser forming technology.

4. The method for preparing a high-performance aluminum alloy for additive manufacturing according to claim 3, characterized in that: Additive manufacturing technology involves laser powder bed melting.

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