A heat-resistant aluminum alloy powder material for 3D printing and preparation method thereof

Abstract

The present invention relates to the technical field of aluminum alloy powder, and in particular to a heat-resistant aluminum alloy powder material for 3D printing and a preparation method thereof, wherein the aluminum alloy powder material comprises: Si 9-15%; Cu 3-6%; Ni 3-6%; Fe 0.5-1.5%; Mn 0.1-1.5%; Cr 0.2-1.0%; Mg 0.5-1.5%; rare earth element 0.5-2.0%; the balance is Al; the rare earth element is one or a combination of two of Er, Sc, and Y elements. The preparation method of the aluminum alloy powder material comprises preparing alloy ingots, smelting, atomizing, and screening according to a proportion. The aluminum alloy powder material can improve the high temperature strength of the aluminum alloy above 200°C, and can inhibit crack formation.

Description

Technical Field

[0001] The invention relates to a heat-resistant aluminum alloy powder material for 3D printing and a preparation method thereof, belonging to the technical field of aluminum alloy powder. Background Art

[0002] Aluminum alloy has low density and high specific strength, and is currently the preferred material for lightweight design in aerospace, rail transit and other fields. As the requirements for operating temperature and strength of aerospace and other parts become higher and higher, the demand for heat-resistant aluminum alloys is also increasing. The existing heat-resistant aluminum alloy material system is mostly aimed at traditional casting, extrusion forming and other processes, while 3D printing technology has the characteristics of layer-by-layer accumulation and rapid solidification, large thermal stress, and obvious anisotropy of the organization. The existing heat-resistant aluminum alloy system is prone to cracking and other problems during the additive manufacturing process. It is necessary to develop a heat-resistant aluminum alloy powder for 3D printing technology, while meeting the needs of aerospace, rail transit and other fields for high heat resistance and high strength.

[0003] Most of the existing designs of 3D printed heat-resistant aluminum alloys are based on the grain refinement mechanism. However, the use of the grain refinement mechanism will lead to complicated processing technology and increase production difficulty. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a heat-resistant aluminum alloy powder material for 3D printing and a preparation method thereof. The aluminum alloy powder material can improve the high-temperature strength of the aluminum alloy above 200°C and can inhibit crack formation.

[0005] The technical solution of the present invention to solve the above technical problems is as follows: a heat-resistant aluminum alloy powder material for 3D printing, wherein the aluminum alloy powder material comprises: Si 9-15%; Cu 3-6%; Ni 3-6%; Fe0.5-1.5%; Mn 0.1-1.5%; Cr0.2-1.0%; Mg 0.5-1.5%; rare earth elements 0.5-2.0%; and the balance is Al.

[0006] Furthermore, the rare earth element is one or a combination of two of Er (erbium), Sc (scandium), and Y (yttrium).

[0007] Preferably, the rare earth element is Er.

[0008] The present invention also discloses a method for preparing a heat-resistant aluminum alloy powder material for 3D printing, the preparation method comprising:

[0009] S1. Preparation of aluminum alloy ingot: preparing aluminum alloy ingot according to the requirements of aluminum alloy powder material;

[0010] S2. Melting: Melting the aluminum alloy ingot under the protection of inert gas;

[0011] S3, atomization: atomization is performed using a supersonic tightly coupled nozzle;

[0012] S4. Screening: Screening the aluminum alloy powder under inert gas protection conditions to obtain the heat-resistant aluminum alloy powder material for 3D printing.

[0013] Furthermore, in step S1, the weight of Mn, Mg and rare earth elements in the aluminum alloy ingot is 5-20% more than that in the aluminum alloy powder material. Considering that a certain proportion of Mn, Mg and rare earth elements are burned during the powder making process, combined with the actual burning of the elements, the content of the above elements in the aluminum alloy ingot is required to be 5-20% higher than the actual composition of the aluminum alloy powder.

[0014] Furthermore, in step S2, the aluminum alloy ingot is placed in a melting crucible for melting, and the crucible is made of graphite.

[0015] Furthermore, in step S2, the smelting temperature is 600-800°C, the smelting time is 10-20min, and the smelting chamber is under a slightly positive pressure, wherein the slightly positive pressure is 0-0.02Pa.

[0016] Furthermore, in step S3, the nozzle outlet convergence angle is 30-50°, and the melt superheat is 50-150°C.

[0017] Furthermore, in step S3, the atomization pressure is 2.0-3.5 Pa, the atomization gas is high-purity argon, and the atomization gas temperature is 20-30°C.

[0018] Furthermore, in step S4, the aluminum alloy powder is sieved to obtain a powder with a particle size range of 15-53 um, which is the heat-resistant aluminum alloy powder material for 3D printing.

[0019] The beneficial effects of the present invention are:

[0020] Elements such as Cu, Ni, Fe, and Mn are added to the aluminum alloy powder material of the present invention to increase the proportion of heat-resistant strengthening phases in the aluminum alloy matrix, so that a certain proportion of strengthening phases still exist in the alloy under high temperature conditions above 200°C, which are dispersed inside the grains, pin dislocations, and hinder grain boundary movement; a certain proportion of rare earth elements are added to increase the solidification rate of the alloy and inhibit microcracks. Rare earth elements can also form fine strengthening phases, pin grain boundaries, increase grain boundary strength and stability under high temperature conditions, and improve material strength.

[0021] In the present invention, the heat-resistant aluminum alloy is based on Al-Si alloy, and the Si element range is around the eutectic point of the Al-Si binary phase diagram, which has good comprehensive performance. Cu, Ni, Cr, Mn, rare earth and other elements are added to the alloy for alloying, wherein the Cu element forms an AlCu strengthening phase with the matrix, and the strengthening phase has good high temperature stability above 200°C. The Ni element and the Cu element synergize to form a grid-like AlCuNi and other precipitation phases, which have higher thermal stability and more obvious effect on improving high temperature strength. The Mg element can form a MgSi2 precipitation phase with the Si element, but the thermal stability of MgSi2 is poor above 200°C, which is not conducive to improving the strength of the alloy. The main function of adding the Mg element in the present invention is to form an AlSiCuMg high temperature strengthening phase with elements such as Cu and Si, and improve the strengthening phase ratio. The addition of Cr and Fe elements can reduce the addition ratio of Ni elements on the one hand, and can also form Al (Fe, Cr, Mn) Si strengthening phases with higher thermal stability with other elements on the other hand, jointly strengthening the aluminum alloy matrix under high temperature conditions and improving the high temperature strength of the material. The addition of trace rare earth elements plays a micro-alloying role. Rare earth elements can form nano-strengthening phases with the matrix, promote the precipitation of high-temperature strength phases such as AlCuNi, and at the same time increase the solidification rate of the alloy, preventing microcracks from being formed during the 3D printing process due to slow solidification and incomplete liquid phase replenishment.

[0022] Compared with the prior art, the present invention selects alloy ingots in the smelting process. Since aluminum alloy materials have low melting points, the alloying elements added, such as Cu, Ni, Fe, and rare earth elements, have high melting points and high specific gravity, if the powder is prepared by mixing the elements in a certain proportion and adding the materials twice, it is easy to cause problems such as element segregation and uneven structure. The present invention uses pre-alloyed ingots as raw materials to prepare aluminum alloy powder, which can effectively avoid the problems of low elements and uneven components caused by the failure to completely melt the alloying elements with high specific gravity and high melting points.

[0023] At the same time, compared with the existing technology, thermal atomization technology is used to atomize the aluminum alloy melt during the atomization process, and the atomizing gas is heated by a gas heating device at a heating temperature of 20-30°C. The use of thermal atomization technology can optimize the airflow field, reduce the risk of blockage caused by too low temperature during the smelting process, effectively reduce the proportion of satellite powder and hollow powder in the powder, and improve the powder morphology.

[0024] Thermal atomization technology is used for atomization to increase the temperature of the atomizing gas and prevent the gas temperature from being too low at the moment of atomization, thereby lowering the temperature of the alloy melt and causing blockage. At the same time, the air flow field is optimized to improve the cooling effect, prevent particle adhesion, and reduce the proportion of satellite powder and hollow powder. DETAILED DESCRIPTION

[0025] The specific implementation of the present invention is described in detail below. The present invention can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used are only for describing specific embodiments and are not intended to limit the present invention.

[0027] Example 1

[0028] A heat-resistant aluminum alloy powder material for 3D printing, the aluminum alloy powder material comprising: Si 12%, Cu 6%, Ni 4%, Fe 1.5%, Mn 1.5%, Cr 0.5%, Mg 1.5%, Er 1.0%, and the balance being Al.

[0029] The preparation method is:

[0030] S1. Preparation of aluminum alloy ingot: prepare aluminum alloy ingot according to the requirements of aluminum alloy powder material, and the weight of Mn, Mg and rare earth element Er in the aluminum alloy ingot is 10% more than that in the aluminum alloy powder material;

[0031] S2. Melting: Place the aluminum alloy ingot into a melting crucible made of graphite, the melting temperature is 600°C, the melting time is 15 minutes, the melting chamber is slightly positive pressure (0-0.02Pa), and is filled with inert gas protection;

[0032] S3, atomization: a supersonic tightly coupled nozzle is used for atomization, the nozzle outlet convergence angle is 45°, the melt superheat is 100°C, the atomization pressure is 3.0Pa, the atomization gas is high-purity argon, and the atomization gas temperature is 25°C;

[0033] S4. Screening: The aluminum alloy powder is screened under inert gas protection to obtain a powder with a particle size range of 15-53 um, which is the heat-resistant aluminum alloy powder material for 3D printing.

[0034] Example 2

[0035] A heat-resistant aluminum alloy powder material for 3D printing, the aluminum alloy powder material comprising: Si 9%, Cu 3%, Ni 6%, Fe 1.0%, Mn 0.5%, Cr 0.2%, Mg 1.0%, Sc 2.0%, and the balance being Al.

[0036] The preparation method is:

[0037] S1. Preparation of aluminum alloy ingot: prepare aluminum alloy ingot according to the requirements of aluminum alloy powder material, and the weight of Mn, Mg and rare earth element Sc in the aluminum alloy ingot is 5% more than that in the aluminum alloy powder material;

[0038] S2. Melting: Place the aluminum alloy ingot into a melting crucible made of graphite, the melting temperature is 800°C, the melting time is 10 minutes, the melting chamber is slightly positive pressure (0-0.02Pa), and is filled with inert gas protection;

[0039] S3, atomization: a supersonic tightly coupled nozzle is used for atomization, the nozzle outlet convergence angle is 30°, the melt superheat is 50°C, the atomization pressure is 2.0Pa, the atomization gas is high-purity argon, and the atomization gas temperature is 20°C;

[0040] S4. Screening: The aluminum alloy powder is screened under inert gas protection to obtain a powder with a particle size range of 15-53 um, which is the heat-resistant aluminum alloy powder material for 3D printing.

[0041] Example 3

[0042] A heat-resistant aluminum alloy powder material for 3D printing, the aluminum alloy powder material comprising: Si 15%, Cu 4%, Ni 3%, Fe 0.5%, Mn 0.1%, Cr 1.0%, Mg 0.5%, Y 0.5%, and the balance being Al.

[0043] The preparation method is:

[0044] S1. Preparation of aluminum alloy ingot: prepare aluminum alloy ingot according to the requirements of aluminum alloy powder material, and the weight of Mn, Mg and rare earth element Y in the aluminum alloy ingot is 20% more than that in the aluminum alloy powder material;

[0045] S2. Melting: Place the aluminum alloy ingot into a melting crucible made of graphite, the melting temperature is 700°C, the melting time is 20 minutes, the melting chamber is slightly positive pressure (0-0.02Pa), and is filled with inert gas protection;

[0046] S3, atomization: a supersonic tightly coupled nozzle is used for atomization, the nozzle outlet convergence angle is 50°, the melt superheat is 150°C, the atomization pressure is 3.5Pa, the atomization gas is high-purity argon, and the atomization gas temperature is 30°C;

[0047] S4. Screening: The aluminum alloy powder is screened under inert gas protection to obtain a powder with a particle size range of 15-53 um, which is the heat-resistant aluminum alloy powder material for 3D printing.

[0048] Example 4

[0049] A heat-resistant aluminum alloy powder material for 3D printing, the aluminum alloy powder material comprising: Si 10%, Cu 3%, Ni 4%, Fe 0.5%, Mn 1.5%, Cr 0.5%, Mg 0.5%, Sc 1.0%, Er 1.0%, and the balance being Al.

[0050] The preparation method is:

[0051] S1. Preparation of aluminum alloy ingot: prepare aluminum alloy ingot according to the requirements of aluminum alloy powder material, and the weight of Mn, Mg and rare earth elements Er and Sc in the aluminum alloy ingot is 10% more than that in the aluminum alloy powder material;

[0052] S2. Melting: Place the aluminum alloy ingot into a melting crucible made of graphite, the melting temperature is 800°C, the melting time is 15 minutes, the melting chamber is slightly positive pressure (0-0.02Pa), and is filled with inert gas protection;

[0053] S3, atomization: a supersonic tightly coupled nozzle is used for atomization, the nozzle outlet convergence angle is 50°, the melt superheat is 120°C, the atomization pressure is 3.0Pa, the atomization gas is high-purity argon, and the atomization gas temperature is 30°C;

[0054] S4. Screening: The aluminum alloy powder is screened under inert gas protection to obtain a powder with a particle size range of 15-53 um, which is the heat-resistant aluminum alloy powder material for 3D printing.

[0055] Example 5

[0056] A heat-resistant aluminum alloy powder material for 3D printing, the aluminum alloy powder material comprising: Si 10%, Cu 4.5%, Ni 3%, Fe 1.5%, Mn 1.0%, Cr 0.2%, Mg 0.8%, Y 0.5%, Er 1.0%, and the balance being Al.

[0057] The preparation method is:

[0058] S1. Preparation of aluminum alloy ingot: prepare aluminum alloy ingot according to the requirements of aluminum alloy powder material, and the weight of Mn, Mg and rare earth elements Y and Er in the aluminum alloy ingot is 15% more than that in the aluminum alloy powder material;

[0059] S2. Melting: Place the aluminum alloy ingot into a melting crucible made of graphite, the melting temperature is 800°C, the melting time is 20 minutes, the melting chamber is slightly positive pressure (0-0.02Pa), and is filled with inert gas protection;

[0060] S3, atomization: a supersonic tightly coupled nozzle is used for atomization, the nozzle outlet convergence angle is 50°, the melt superheat is 120°C, the atomization pressure is 3.0Pa, the atomization gas is high-purity argon, and the atomization gas temperature is 30°C;

[0061] S4. Screening: The aluminum alloy powder is screened under inert gas protection to obtain a powder with a particle size range of 15-53 um, which is the heat-resistant aluminum alloy powder material for 3D printing.

[0062] The performance test data of the aluminum alloy powder materials prepared in Examples 1 to 5 are shown in Table 1 below:

[0063] Table 1 Performance test data of aluminum alloy powder materials prepared in Example 1 to Example 5

[0064]

[0065] Comparative Example 1

[0066] The aluminum alloy powder material is prepared by the same method as in Example 1, except that no rare earth element is added.

[0067] The aluminum alloy powder material of this comparative example 1 includes: Si 12%, Cu 6%, Ni 4%, Fe 1.5%, Mn 1.5%, Cr 0.5%, Mg 1.5%, and the balance is Al.

[0068] Other preparation methods and process conditions are the same as those in Example 1, and the specific preparation method is:

[0069] S1. Preparation of aluminum alloy ingot: prepare aluminum alloy ingot according to the requirements of aluminum alloy powder material, and the weight of Mn and Mg in the aluminum alloy ingot is 10% more than that in the aluminum alloy powder material;

[0070] S2. Melting: Place the aluminum alloy ingot into a melting crucible made of graphite, the melting temperature is 600°C, the melting time is 15 minutes, the melting chamber is slightly positive pressure (0-0.02Pa), and is filled with inert gas protection;

[0071] S3, atomization: a supersonic tightly coupled nozzle is used for atomization, the nozzle outlet convergence angle is 45°, the melt superheat is 100°C, the atomization pressure is 3.0Pa, the atomization gas is high-purity argon, and the atomization gas temperature is 25°C;

[0072] S4. Screening: The aluminum alloy powder is screened under inert gas protection to obtain a powder with a particle size range of 15-53 um, which is the heat-resistant aluminum alloy powder material for 3D printing.

[0073] Comparative Example 2

[0074] The aluminum alloy powder material was prepared by the same method as in Example 1, except that Ni was not added.

[0075] The aluminum alloy powder material of Comparative Example 2 includes: Si 12%, Cu 6%, Fe 1.5%, Mn 1.5%, Cr 0.5%, Mg 1.5%, Er 1.0%, and the balance is Al.

[0076] Other preparation methods and process conditions are the same as those in Example 1, and the specific preparation method is:

[0077] S1. Preparation of aluminum alloy ingot: prepare aluminum alloy ingot according to the requirements of aluminum alloy powder material, and the weight of Mn, Mg and rare earth element Er in the aluminum alloy ingot is 10% more than that in the aluminum alloy powder material;

[0078] S2. Melting: Place the aluminum alloy ingot into a melting crucible made of graphite, the melting temperature is 600°C, the melting time is 15 minutes, the melting chamber is slightly positive pressure (0-0.02Pa), and is filled with inert gas protection;

[0079] S3, atomization: a supersonic tightly coupled nozzle is used for atomization, the nozzle outlet convergence angle is 45°, the melt superheat is 100°C, the atomization pressure is 3.0Pa, the atomization gas is high-purity argon, and the atomization gas temperature is 25°C;

[0080] S4. Screening: The aluminum alloy powder is screened under inert gas protection to obtain a powder with a particle size range of 15-53 um, which is the heat-resistant aluminum alloy powder material for 3D printing.

[0081] Comparative Example 3

[0082] The aluminum alloy powder material was prepared by the same method as in Example 1, except that no Cu was added.

[0083] The aluminum alloy powder material of Comparative Example 3 includes: Si 12%, Ni 4%, Fe 1.5%, Mn 1.5%, Cr 0.5%, Mg 1.5%, Er 1.0%, and the balance is Al.

[0084] Other preparation methods and process conditions are the same as those in Example 1, and the specific preparation method is:

[0085] S1. Preparation of aluminum alloy ingot: prepare aluminum alloy ingot according to the requirements of aluminum alloy powder material, and the weight of Mn, Mg and rare earth element Er in the aluminum alloy ingot is 10% more than that in the aluminum alloy powder material;

[0086] S2. Melting: Place the aluminum alloy ingot into a melting crucible made of graphite, the melting temperature is 600°C, the melting time is 15 minutes, the melting chamber is slightly positive pressure (0-0.02Pa), and is filled with inert gas protection;

[0087] S3, atomization: a supersonic tightly coupled nozzle is used for atomization, the nozzle outlet convergence angle is 45°, the melt superheat is 100°C, the atomization pressure is 3.0Pa, the atomization gas is high-purity argon, and the atomization gas temperature is 25°C;

[0088] S4. Screening: The aluminum alloy powder is screened under inert gas protection to obtain a powder with a particle size range of 15-53 um, which is the heat-resistant aluminum alloy powder material for 3D printing.

[0089] Comparative Example 4

[0090] The aluminum alloy powder material was prepared by the same method as in Example 1, except that no Cr was added.

[0091] The aluminum alloy powder material of Comparative Example 4 includes: Si 12%, Cu 6%, Ni 4%, Fe 1.5%, Mn 1.5%, Mg 1.5%, Er 1.0%, and the balance is Al.

[0092] Other preparation methods and process conditions are the same as those in Example 1, and the specific preparation method is:

[0093] S1. Preparation of aluminum alloy ingot: prepare aluminum alloy ingot according to the requirements of aluminum alloy powder material, and the weight of Mn, Mg and rare earth element Er in the aluminum alloy ingot is 10% more than that in the aluminum alloy powder material;

[0094] S2. Melting: Place the aluminum alloy ingot into a melting crucible made of graphite, the melting temperature is 600°C, the melting time is 15 minutes, the melting chamber is slightly positive pressure (0-0.02Pa), and is filled with inert gas protection;

[0095] S3, atomization: a supersonic tightly coupled nozzle is used for atomization, the nozzle outlet convergence angle is 45°, the melt superheat is 100°C, the atomization pressure is 3.0Pa, the atomization gas is high-purity argon, and the atomization gas temperature is 25°C;

[0096] S4. Screening: The aluminum alloy powder is screened under inert gas protection to obtain a powder with a particle size range of 15-53 um, which is the heat-resistant aluminum alloy powder material for 3D printing.

[0097] Comparative Example 5

[0098] The aluminum alloy powder material was prepared by the same method as in Example 1, except that the amount of rare earth element added was 0.2% (lower than the amount specified in the present invention).

[0099] The aluminum alloy powder material of Comparative Example 5 includes: Si 12%, Cu 6%, Ni 4%, Fe 1.5%, Mn 1.5%, Cr 0.5%, Mg 1.5%, Er 0.2%, and the balance is Al.

[0100] Other preparation methods and process conditions are the same as those in Example 1, and the specific preparation method is:

[0101] S1. Preparation of aluminum alloy ingot: prepare aluminum alloy ingot according to the requirements of aluminum alloy powder material, and the weight of Mn, Mg and rare earth element Er in the aluminum alloy ingot is 10% more than that in the aluminum alloy powder material;

[0102] S2. Melting: Place the aluminum alloy ingot into a melting crucible made of graphite, the melting temperature is 600°C, the melting time is 15 minutes, the melting chamber is slightly positive pressure (0-0.02Pa), and is filled with inert gas protection;

[0103] S3, atomization: a supersonic tightly coupled nozzle is used for atomization, the nozzle outlet convergence angle is 45°, the melt superheat is 100°C, the atomization pressure is 3.0Pa, the atomization gas is high-purity argon, and the atomization gas temperature is 25°C;

[0104] S4. Screening: The aluminum alloy powder is screened under inert gas protection to obtain a powder with a particle size range of 15-53 um, which is the heat-resistant aluminum alloy powder material for 3D printing.

[0105] Comparative Example 6

[0106] The aluminum alloy powder material was prepared by the same method as in Example 1, except that the amount of rare earth element added was 2.5% (higher than the amount specified in the present invention).

[0107] The aluminum alloy powder material of Comparative Example 6 includes: Si 12%, Cu 6%, Ni 4%, Fe 1.5%, Mn 1.5%, Cr 0.5%, Mg 1.5%, Er 2.5%, and the balance is Al.

[0108] Other preparation methods and process conditions are the same as those in Example 1, and the specific preparation method is:

[0109] S1. Preparation of aluminum alloy ingot: prepare aluminum alloy ingot according to the requirements of aluminum alloy powder material, and the weight of Mn, Mg and rare earth element Er in the aluminum alloy ingot is 10% more than that in the aluminum alloy powder material;

[0110] S2. Melting: Place the aluminum alloy ingot into a melting crucible made of graphite, the melting temperature is 600°C, the melting time is 15 minutes, the melting chamber is slightly positive pressure (0-0.02Pa), and is filled with inert gas protection;

[0111] S3, atomization: a supersonic tightly coupled nozzle is used for atomization, the nozzle outlet convergence angle is 45°, the melt superheat is 100°C, the atomization pressure is 3.0Pa, the atomization gas is high-purity argon, and the atomization gas temperature is 25°C;

[0112] S4. Screening: The aluminum alloy powder is screened under inert gas protection to obtain a powder with a particle size range of 15-53 um, which is the heat-resistant aluminum alloy powder material for 3D printing.

[0113] Comparative Example 7

[0114] The aluminum alloy powder material is prepared by the same method as in Example 1, except that Cr is replaced by Zr.

[0115] The aluminum alloy powder material of this comparative example 7 includes: Si 12%, Cu 6%, Ni 4%, Fe 1.5%, Mn 1.5%, Zr 0.5%, Mg 1.5%, Er 1.0%, and the balance is Al.

[0116] The preparation method is:

[0117] S1. Preparation of aluminum alloy ingot: prepare aluminum alloy ingot according to the requirements of aluminum alloy powder material, and the weight of Mn, Mg and rare earth element Er in the aluminum alloy ingot is 10% more than that in the aluminum alloy powder material;

[0118] S2. Melting: Place the aluminum alloy ingot into a melting crucible made of graphite, the melting temperature is 600°C, the melting time is 15 minutes, the melting chamber is slightly positive pressure (0-0.02Pa), and is filled with inert gas protection;

[0119] S3, atomization: a supersonic tightly coupled nozzle is used for atomization, the nozzle outlet convergence angle is 45°, the melt superheat is 100°C, the atomization pressure is 3.0Pa, the atomization gas is high-purity argon, and the atomization gas temperature is 25°C;

[0120] S4. Screening: The aluminum alloy powder is screened under inert gas protection to obtain a powder with a particle size range of 15-53 um, which is the heat-resistant aluminum alloy powder material for 3D printing.

[0121] The performance test data of the aluminum alloy powder materials prepared in Comparative Examples 1 to 7 are shown in Table 2 below:

[0122] Table 2 Performance test data of aluminum alloy powder materials prepared in Comparative Examples 1 to 6

[0123]

[0124] Comparing the performance data of the aluminum alloy powder materials of Comparative Example 1 and Example 1, it can be seen that: No rare earth elements are added in Comparative Example 1, which will lead to a decrease in tensile strength, yield strength and elongation. In addition, the experimental data of Comparative Examples 5 and 6 show that adding too little or too much rare earth elements will lead to a decrease in product performance. Because the addition of rare earth elements can play a micro-alloying role, rare earth elements can form nano-strengthening phases with the matrix, promote the precipitation of high-temperature strength phases such as AlCuNi, and at the same time can increase the solidification rate of the alloy, and prevent the alloy from forming microcracks due to slow solidification speed and incomplete liquid phase replenishment during the 3D printing process; in addition, if the amount of rare earth elements added is too much, it will easily cause element segregation, uneven organization and other problems, which will ultimately affect the strength performance of the product.

[0125] Comparing the performance data of Comparative Examples 2 and 3 with the performance data of Example 1, it can be seen that if Ni and Cu are not added to the aluminum alloy powder material, the performance of the product will be significantly reduced, because the Ni element and the Cu element can play a synergistic role to form a grid-like AlCuNi and other precipitation phases, thereby making the thermal stability of the aluminum alloy powder material higher and more conducive to the improvement of high-temperature strength. In addition, if Cu is not added, the Mg element cannot form the AlSiCuMg high-temperature strengthening phase with Cu, Si and other elements, thereby reducing the proportion of the strengthening phase, and ultimately affecting the product performance.

[0126] Comparing the performance data of Comparative Example 4 with the performance data of Example 1, it can be seen that if the Cr element is not added to the aluminum alloy powder material, the performance of the product will also be significantly reduced. In addition, comparing the performance data of Comparative Example 7 with the performance data of Example 1, it can be seen that if Zr is replaced with Cr in the aluminum alloy powder material, the high-temperature strength of the material will also be significantly reduced. Because the addition of Cr can form Al(Fe, Cr, Mn)Si strengthening phase with higher thermal stability with other elements, it can jointly strengthen the aluminum alloy matrix under high temperature conditions and improve the high-temperature strength of the material.

[0127] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are exhaustively listed. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0128] For those skilled in the art, several modifications and improvements may be made without departing from the concept of the present invention, all of which belong to the protection scope of the present invention. The protection scope of the present invention shall be based on the attached claims.

Claims

1. A heat-resistant aluminum alloy powder material for 3D printing, characterized in that: The aluminum alloy powder material comprises: Si9-15%; Cu 3-6%; Ni 3-6%; Fe 0.5-1.5%; Mn 0.1-1.5%; Cr 0.2-1.0%; Mg 0.5-1.5%; rare earth element 0.5-2.0%; the balance is Al; The rare earth element is one or a combination of two of Er, Sc and Y.

2. The heat-resistant aluminum alloy powder material for 3D printing according to claim 1, characterized in that: The rare earth element is Er.

3. A method for preparing a heat-resistant aluminum alloy powder material for 3D printing according to any one of claims 1-2, characterized in that: The preparation method is: S1. Preparation of aluminum alloy ingot: preparing aluminum alloy ingot according to the requirements of aluminum alloy powder material; S2. Melting: Melting the aluminum alloy ingot under the protection of inert gas; S3, atomization: atomization is performed using a supersonic tightly coupled nozzle; S4, screening: screening the aluminum alloy powder under inert gas protection conditions to obtain the heat-resistant aluminum alloy powder material for 3D printing; In step S3, the atomization pressure is 2.0-3.5 Pa, the atomization gas is high-purity argon, and the atomization gas temperature is 20-30°C.

4. The method for preparing a heat-resistant aluminum alloy powder material for 3D printing according to claim 3, characterized in that: In step S1, the weight of Mn, Mg and rare earth elements in the aluminum alloy ingot is 5-20% more than that in the aluminum alloy powder material.

5. The method for preparing a heat-resistant aluminum alloy powder material for 3D printing according to claim 3, characterized in that: In step S2, the aluminum alloy ingot is placed in a melting crucible for melting, and the crucible is made of graphite.

6. The method for preparing a heat-resistant aluminum alloy powder material for 3D printing according to claim 3, characterized in that: In step S2, the smelting temperature is 600-800°C, the smelting time is 10-20 minutes, and the smelting chamber is under a slightly positive pressure.

7. The method for preparing a heat-resistant aluminum alloy powder material for 3D printing according to claim 3, characterized in that: In step S3, the nozzle outlet convergence angle is 30-50°, and the melt superheat is 50-150°C.

8. The method for preparing a heat-resistant aluminum alloy powder material for 3D printing according to claim 3, characterized in that: In step S4, the aluminum alloy powder is sieved to obtain a powder with a particle size range of 15-53 um, which is the heat-resistant aluminum alloy powder material for 3D printing.

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