A rare earth modified additive manufacturing high-entropy aluminum-based alloy powder, a preparation method, application and aluminum-based alloy thereof

Abstract

The application discloses a rare earth modified additive manufacturing high-entropy aluminum-based alloy, a preparation method and application thereof, and the aluminum-based alloy, and the alloy powder is a pre-alloy powder, and the alloy powder comprises, in terms of mass percentage, Er: 0.5-4 wt%; Fe: 1-5.5 wt%; Cr: 1-5.5 wt%; Mn: 0.5-5 wt%; Ni: 0.5-5.5 wt%; Sc: 0.1-1.3 wt%; Zr: 0.2-1.3 wt%; Si: 0.1-1.2 wt%, and the rest is Al. The alloy powder of the application has reduced metallurgical defects of a part after laser 3D printing, has higher compactness, and has better comprehensive performance than existing additive manufacturing aluminum alloys, in particular, high-temperature tensile strength, solves the problem of low high-temperature mechanical properties of the existing additive manufacturing aluminum alloys, and also overcomes the common hot cracking problem of the additive manufacturing aluminum alloys.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of materials for additive manufacturing, and particularly relates to a rare earth modified additive manufacturing high-entropy aluminum-based alloy, a preparation method and application thereof, and an aluminum-based alloy. BACKGROUND

[0002] Aluminum alloys have a wide range of applications in the fields of aviation, aerospace, automobiles, and ships due to their high specific strength, good machinability, high corrosion resistance, and excellent electrical and thermal conductivity. Meanwhile, lightweight hollow structures formed by additive manufacturing are widely used in heat-resistant oil pipes of spacecraft, compressor half-shroud components of aircraft engines, and other parts, which are required to serve in high-temperature conditions of 150-400℃ for a long time while bearing large loads. Therefore, there are higher requirements for the high-temperature mechanical strength, heat resistance, and toughness of aluminum alloys. However, the service temperature of traditional aluminum alloys is generally lower than 200℃, and their tensile strength and creep resistance cannot meet the above requirements. Therefore, it is necessary to find an aluminum alloy composition with excellent performance.

[0003] Compared with traditional alloys, the Er modified additive manufacturing high-entropy aluminum-based alloy has more excellent comprehensive performance, which integrates good mechanical properties, high heat resistance and oxidation resistance, and high corrosion resistance and wear resistance. The addition of rare earth elements can improve the metallographic structure of aluminum alloys and refine the grains, thereby greatly improving the strength of the alloy through the mechanism of fine-grain strengthening. However, traditional multi-component high-entropy solute reinforced Al alloys for laser additive manufacturing have problems such as poor mechanical properties and easy cracking. In order to adapt to the dynamic metallurgy of additive manufacturing and improve the performance of preformed aluminum alloys, it is necessary to invent a high-entropy solute reinforced heat-resistant aluminum alloy composition, printing process, and heat treatment process specially suitable for additive manufacturing. SUMMARY

[0004] This section aims to summarize some aspects of the embodiments of the present application and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of the specification to avoid obscuring the purpose of this section, abstract, and title, and such simplifications or omissions cannot be used to limit the scope of the present application.

[0005] In view of the above and / or the problems of significant reduction in high-temperature mechanical properties, low strength, and low creep resistance of additive manufacturing aluminum alloys in the prior art, the present application is proposed.

[0006] One of the purposes of the present application is to provide a rare earth modified additive manufacturing high-entropy aluminum-based alloy powder, in which elements such as Er, Fe, Cr, Mn, Ni, Sc, Zr, Si, etc. are added, so that the multi-component high-entropy aluminum alloy is suitable for the additive manufacturing process, and the super-saturated solid solution of the elements in the multi-component high-entropy aluminum alloy is realized by using the selective laser melting technology, and the multi-scale synergistic strengthening is realized.

[0007] To solve the above technical problems, the present application provides the following technical scheme: a rare earth modified additive manufacturing high-entropy aluminum-based alloy, the alloy powder is a pre-alloy powder, and the mass percentage comprises: Er: 0.5-4wt%; Fe: 1-5.5wt%; Cr: 1-5.5wt%; Mn: 0.5-5wt%; Ni: 0.5-5.5wt%; Sc: 0.1-1.3wt%, Zr: 0.2-1.3wt%; Si: 0.1-1.2wt%, and the rest is Al.

[0008] As a preferred scheme of the rare earth modified additive manufacturing high-entropy aluminum-based alloy powder of the present application, the mass percentage comprises: Er: 0.5-3wt%; Fe: 2.5-5.5wt%; Cr: 2-5wt%; Mn: 2-5wt%; Ni: 2.5-5.5wt%; Sc: 0.1-1.1wt%, Zr: 0.3-1.3wt%; Si: 0.2-1.2wt%, and the rest is Al.

[0009] As a preferred scheme of the rare earth modified additive manufacturing high-entropy aluminum-based alloy powder of the present application, the mass percentage comprises: Er: 0.5-3wt%; Fe: 2.5-5.5wt%; Cr: 2-5wt%; Mn: 2-5wt%; Ni: 2.5-5.5wt%; Sc: 0.1-1.1wt%, Zr: 0.3-1.3wt%; Si: 0.2-1.2wt%, and the rest is Al.

[0010] Another purpose of the present application is to provide a preparation method of the rare earth modified additive manufacturing high-entropy aluminum-based alloy powder as described above, comprising,

[0011] Preparing the metal powder, and preparing the metal powder according to the mass percentage as described above;

[0012] Vacuum melting, vacuum melting the prepared metal powder;

[0013] Atomization powdering, atomization powdering after the vacuum melting to obtain the rare earth modified additive manufacturing high-entropy aluminum-based alloy powder.

[0014] As a preferred scheme of the preparation method of the rare earth modified additive manufacturing high-entropy aluminum-based alloy powder of the present application, wherein: the vacuum melting has a melting temperature of 600-850 DEG C, and the gas pressure in the melting furnace is 0.5-0.6 MPa; the atomization powdering has an atomization pressure of 4-5.5 MPa.

[0015] Another object of the present application is to provide the application of the rare earth modified additive manufacturing high-entropy aluminum-based alloy powder as described above in 3D printing.

[0016] Another object of the present application is to provide a preparation method of a rare earth modified additive manufacturing high-entropy aluminum-based alloy, comprising,

[0017] The rare earth modified additive manufacturing high-entropy aluminum-based alloy powder as described above is subjected to screening and drying treatment;

[0018] After the treatment, 3D printing is performed.

[0019] As a preferred scheme of the preparation method of the rare earth modified additive manufacturing high-entropy aluminum-based alloy of the present application, wherein: the screening has an alloy powder particle size of 15-53 μm after screening;

[0020] The 3D printing is laser powder bed 3D printing, and has a laser power of 200-400 W, a scanning speed of 500-1200 mm / s, a scanning interval of 0.04-0.14 mm, a scanning layer thickness of 0.03-0.05 mm, and a scanning strategy of a rotation angle of 67° between adjacent layers.

[0021] As a preferred scheme of the preparation method of the rare earth modified additive manufacturing high-entropy aluminum-based alloy of the present application, wherein: further comprising,

[0022] The heat treatment is performed after the 3D printing, and the printed product is obtained after heat treatment and annealing;

[0023] The heat treatment temperature is 300-325 DEG C, the heating speed is 50 DEG C / min, and the holding time is 5-6 h.

[0024] Another object of the present application is to provide the rare earth modified additive manufacturing high-entropy aluminum-based alloy obtained by the preparation method as described above, and the alloy has the following properties:

[0025] (a) the room temperature yield strength is 299-343 MPa, the elongation is more than 4%, and the tensile strength is 359-403 MPa;

[0026] (b) without heat treatment, the yield strength at 200 DEG C is 246-295 MPa, the tensile strength is 266-312 MPa; the yield strength at 250 DEG C is 215-265 MPa, the tensile strength is 224-272 MPa, and the elongation is 8-10%;

[0027] (c) After heat treatment, the room temperature tensile strength reaches 440-482 MPa.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The addition of rare earth elements in this invention acts as a modifier, significantly improving the crystallization conditions of aluminum alloys, thereby refining their microstructure and grain size. Simultaneously, rare earth elements are inherently reactive, reacting with gases such as hydrogen, metals, and non-metals like sulfur to form chemically stable compounds. Upon contact with many metallic or non-metallic elements, rare earth elements undergo chemical reactions to generate compounds with high melting points. This property allows for the removal of hydrogen, refining, and purification. It removes gases and harmful impurities from aluminum alloys, reduces crack initiation points, and thus improves the alloy's strength, processing performance, hardness, and toughness. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced 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 based on these drawings without creative effort. Wherein:

[0031] Figure 1 This is a scanning image of the morphology of the rare earth-modified additive manufacturing high-entropy aluminum-based alloy powder prepared in Example 1;

[0032] Figure 2 Metallographic image of the rare earth-modified additive manufacturing high-entropy aluminum-based alloy prepared in Example 1;

[0033] Figure 3 Metallographic image of the rare earth-modified additive high-entropy aluminum-based alloy prepared in Example 1 after corrosion;

[0034] Figure 4 Scanning image of the rare earth-modified additive manufacturing high-entropy aluminum-based alloy prepared in Example 1. Detailed Implementation

[0035] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0036] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application can be practiced without the specific details set forth in this description, that the present application can be practiced with other than the described embodiments, and that the present application can be practiced with other than the described embodiments, and that the present application can be practiced in other ways not specifically described herein. It is therefore contemplated to this application not be limited to the specific embodiments disclosed in the following description.

[0037] Secondly, the "one embodiment" or "an embodiment" referred to herein means a specific feature, structure, or characteristic under consideration or implementation. The "in one embodiment" appearing in different places in the specification does not mean the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments.

[0038] Unless otherwise specified, the raw materials used in the examples are commercially available.

[0039] The rare earth modified additive manufacturing high-entropy aluminum-based alloy powder provided by the present application is a pre-alloy powder, which comprises Er, Fe, Cr, Mn, Ni, Sc, Zr, Si, and the rest is Al.

[0040] The component design is based on:

[0041] The role of Er element: adding an appropriate amount of Er can significantly refine the grain structure of aluminum alloy and improve the mechanical properties of the alloy. It can achieve the effects of hydrogen removal, refining and purification. Only a trace amount is needed in the alloy to improve the mechanical properties.

[0042] The role of Fe element: adding Fe can improve the high-temperature performance of the alloy and improve its processing performance.

[0043] The role of Cr element: under the condition of rapid cooling unique to 3D printing, a large number of dispersed distribution and thermal stability precipitates are formed, which improves the heat resistance of the aluminum alloy, and also plays a role of solid solution strengthening, reduces the stacking fault energy of the alloy, and forms high-density stacking faults and twins.

[0044] The role of Mn element: a high content of Mn element is added in the multi-component high-entropy aluminum alloy, which has two main purposes. First, it is to form supersaturated solid solution to greatly improve the solid solution strength effect. Second, it is to form intermetallic compounds with Al elements to control the recrystallization process, refine the grain, and reduce the sensitivity of cracks.

[0045] The role of Ni element: it can improve the corrosion resistance.

[0046] Effects of Sc and Zr: Sc and Zr elements can form a low-volume fraction of Al3(Sc, Zr) nano-phase with Al, significantly refine the grain, increase the liquid supply to reduce cracks, and make the alloy have excellent room temperature mechanical properties. At the same time, the secondary Al3(Sc, Zr) particles can also hinder the recrystallization of the aluminum alloy and improve the high-temperature strength.

[0047] Effects of Si: Si element promotes liquid feeding and improves high-temperature strength.

[0048] Synergistic effect of the above elements: the addition of the above elements also has a synergistic effect, which greatly improves the mechanical properties and surface hardness of the rare earth modified additive manufacturing high-entropy aluminum-based alloy parts.

[0049] The present application is printed by a selective laser melting device, and specific process parameters are set for the special powder proposed in the present application, that is, the laser scanning strategy is set according to the needs of the printed parts, the appropriate process parameters are selected, and the rare earth modified additive manufacturing high-entropy aluminum-based alloy powder is selected, so that the strength of the printed parts is uniform, and the printing process is carried out in an inert gas environment.

[0050] The following examples also relate to high-temperature tensile tests, and the heating rate is 10℃ / min, and the temperature is kept for half an hour before tensile test to achieve thermal equilibrium.

[0051] Example 1

[0052] (1) Configure metal powder, prepare according to the mass percentage content, and the composition is as follows: Er: 3wt%; Fe: 5.5wt%; Cr: 5wt%; Mn: 5wt%; Ni: 5.5wt%; Sc: 1.1wt%, Zr: 1.3wt%; Si: 1.2wt%, and the rest is Al;

[0053] (2) Vacuum melting: put the pure metal blocks containing the above components into a vacuum induction furnace for heating and melting; the vacuum melting temperature is 850℃, and the gas pressure in the melting furnace is 0.6MPa;

[0054] (3) Atomization powdering: the metal droplets are atomized by using argon as the medium, the atomization pressure is 8.5MPa, and the pre-alloy powder is obtained;

[0055] (4) Screening: screen and grade the pre-alloy powder, and screen out the powder with a particle size of 15-53μm as the raw material powder required for 3D printing;

[0056] (5) Drying treatment: dry the screened pre-alloy powder in a drying box, the drying temperature is 90℃, and the drying treatment time is 8 hours;

[0057] (6) 3D printing: the 3D printing aluminum alloy powder above is subjected to selective laser melting (SLM), and the substrate is heated to 200℃ during printing; the printing process is: laser power 300W; scanning speed 1000mm / s; scanning interval 0.1mm; scanning layer thickness 0.05mm; the scanning strategy is that the rotation angle between adjacent layers is 67°, and a rare earth modified additive manufacturing high-entropy aluminum-based alloy sample is obtained.

[0058] The metallurgical defects are few under light microscopy, and the sample density reaches 99.4%, and the average hardness is 160HV 0.2 The above.

[0059] The rare earth modified additive manufacturing high-entropy aluminum-based alloy powder obtained by the atomization powder preparation step has a metallographic phase as shown in Figure 1 It can be seen that the powder particle shape is spherical.

[0060] The phase diagram of the prepared rare earth modified additive manufacturing high-entropy aluminum-based alloy is as shown in Figure 2 The sample corrosion metallographic phase is as shown in Figure 3 The sample scanning diagram is as shown in Figure 4 .

[0061] From Figure 2 It can be seen that the sample has fewer pores and higher density. From Figure 3 It can be seen that the molten pool morphology is fan-shaped, the aspect ratio is large, the effective heat dissipation efficiency is increased, and the cooling rate of the molten pool is increased.

[0062] From Figure 4 It can be seen that the grain size of the remelted area of the molten pool boundary is very small. After heat treatment, Al3(Sc, Zr) nanoparticles are dispersedly distributed in the matrix, which has similar crystallographic structure with the matrix and is completely coherent, so it can effectively inhibit recrystallization, thereby improving the strength of the alloy.

[0063] The parts of this composition are laser 3D printed in this embodiment, and the printed parts have high dimensional accuracy, fine structure, and no segregation of composition; and excellent mechanical properties, the room temperature yield strength is about 343MPa, and the tensile strength exceeds 403MPa; at the same time, the multi-component high-entropy aluminum alloy sample without heat treatment has a yield strength of 295MPa and a tensile strength of 312MPa at 200℃, a yield strength of 265MPa and a tensile strength of 272MPa at 250℃, which is much higher than the high-temperature mechanical properties of most existing additive manufacturing aluminum alloys; the multi-component high-entropy aluminum alloy sample not only has high tensile properties, but also has high elongation, the elongation at room temperature exceeds 4%, and the elongation at 200℃ exceeds 8%.

[0064] The obtained rare earth modified additive manufacturing high-entropy aluminum-based alloy sample is heat treated: the heat treatment temperature is 325℃, the heating speed is 50℃ / min, and the holding time is 5h. After heat treatment, the tensile property is not only not reduced, but also produces nano-scale precipitates to inhibit grain growth and sub-micron dispersion phase, and the tensile strength reaches 482MPa.

[0065] Example 2

[0066] The difference between this example 2 and example 1 is that the mass percentage content of the metal powder in step (1) is different, and the composition is as follows: Er: 3wt%; Fe: 4.5wt%; Cr: 4wt%; Mn: 4wt%; Ni: 4.5wt%; Sc: 1.1wt%, Zr: 1.3wt%; Si: 1.2wt%, and the rest is Al. Other steps are the same as example 1, and a rare earth modified additive manufacturing high-entropy aluminum-based alloy sample is obtained.

[0067] The obtained rare earth modified additive manufacturing high-entropy aluminum-based alloy sample is tested by the same performance test as example 1, and in the density test, the sample density reaches 99%, and the average hardness is 150HV 0.2 Above, the yield strength at room temperature is 312MPa, and the tensile strength exceeds 365MPa. At the same time, the yield strength of the part without heat treatment at 200℃ can reach 265MPa, and the tensile strength is 289MPa.

[0068] Example 3

[0069] (1) Configure the metal powder, and prepare according to the mass percentage content, and the composition is as follows: Er: 0.5wt%; Fe: 1wt%; Cr: 1wt%; Mn: 0.5wt%; Ni: 0.5wt%; Sc: 0.1wt%, Zr: 0.2wt%; Si: 0.1wt%, and the rest is Al;

[0070] (2) Vacuum melting: put the pure metal blocks containing the above components into a vacuum induction furnace for heating and melting; the vacuum melting temperature is 850℃, and the gas pressure in the melting furnace is 0.6MPa;

[0071] (3) Atomization: use argon as the medium to atomize the metal droplets, and the atomization pressure is 8.5MPa, to obtain pre-alloy powder;

[0072] (4) Screening: screen and grade the pre-alloy powder, and screen out the powder of 15-53μm as the raw material powder required for 3D printing;

[0073] (5) Drying treatment: put the screened pre-alloy powder into a drying box for drying, the drying temperature is 90℃, and the drying treatment time is 8h;

[0074] (6) 3D printing: the 3D printing aluminum alloy powder above is subjected to selective laser melting (SLM), and the substrate is heated to 200°C during printing; the printing process is as follows: laser power 300 W; scanning speed 1000 mm / s; scanning interval 0.1 mm; scanning layer thickness 0.05 mm; the scanning strategy is that the rotation angle between adjacent layers is 67°, and a plurality of groups of high-entropy aluminum alloy samples are obtained.

[0075] In the density test, the density reaches 99.3%, and the average hardness is 149.2 HV 0.2 . The yield strength at room temperature is 299 MPa, and the tensile strength is 359 MPa. At the same time, the yield strength of the unheated part at 200°C is 246 MPa, and the tensile strength is 266 MPa.

[0076] Example 4

[0077] The difference between this embodiment 4 and embodiment 1 is that the mass percentage content of the metal powder in step (1) is different, and the composition is as follows: Er: 3wt%; Fe: 5.5wt%; Cr: 5wt%; Mn: 5wt%; Ni: 5.5wt%; Sc: 0.1wt%, Zr: 0.3wt%; Si: 0.2wt%, and the rest is Al. The other steps are the same as those in embodiment 1, and a plurality of groups of high-entropy aluminum alloy samples are obtained.

[0078] The obtained plurality of groups of high-entropy aluminum alloy samples are subjected to the same performance test as in embodiment 1, and in the density test, the density reaches 99.2%, and the average hardness is 159.4 HV 0.2 . The yield strength at room temperature is 337 MPa, and the tensile strength is 396.5 MPa. At the same time, the yield strength of the unheated part at 200°C is 286.5 MPa, and the tensile strength is 305.4 MPa.

[0079] Example 5

[0080] The difference between this embodiment 5 and embodiment 1 is that the mass percentage content of the metal powder in step (1) is different, and the composition is as follows: Er: 3wt%; Fe: 2.5wt%; Cr: 2wt%; Mn: 2wt%; Ni: 2.5wt%; Sc: 1.1wt%, Zr: 1.3wt%; Si: 1.2wt%, and the rest is Al. The other steps are the same as those in embodiment 1, and a plurality of groups of high-entropy aluminum alloy samples are obtained.

[0081] The obtained plurality of groups of high-entropy aluminum alloy samples are subjected to the same performance test as in embodiment 1, and in the density test, the density reaches 99.1%, and the average hardness is 155 HV 0.2 . The yield strength at room temperature is 334 MPa, and the tensile strength is 388 MPa. At the same time, the yield strength of the unheated part at 200°C is 279 MPa, and the tensile strength is 299.3 MPa.

[0082] Comparative Example 1

[0083] The difference between Comparative Example 1 and Example 1 is that the mass percentage content of metal powder in step (1) is different, and the composition is as follows: Fe: 5.5wt%; Cr: 5wt%; Mn: 5wt%; Ni: 5.5wt%; Sc: 1.1wt%, Zr: 1.3wt%; Si: 1.2wt%, and the rest is Al. Other steps are the same as Example 1, and a rare earth modified additive manufacturing high-entropy aluminum-based alloy sample is obtained.

[0084] The obtained rare earth modified additive manufacturing high-entropy aluminum-based alloy sample is tested for performance in the same way as Example 1. In the density test, the density reaches 99.6%, and the average hardness is 132HV 0.2 . The yield strength at room temperature is 266MPa, and the tensile strength is 286MPa. At the same time, the yield strength of the unheated part at 200℃ is 201MPa, and the tensile strength is 214MPa. The alloy of Comparative Example 1 lacks Er, and the performance is poorer than that of Example 1.

[0085] Comparative Example 2

[0086] The difference between Comparative Example 2 and Example 1 is that the mass percentage content of metal powder in step (1) is different, and the composition is as follows: Er: 3wt%; Fe: 5.5wt%; Cr: 5wt%; Mn: 5wt%; Ni: 5.5wt%; and the rest is Al. Other steps are the same as Example 1, and a rare earth modified additive manufacturing high-entropy aluminum-based alloy sample is obtained.

[0087] The obtained rare earth modified additive manufacturing high-entropy aluminum-based alloy sample is tested for performance in the same way as Example 1. In the density test, the density reaches 98.6%, and the average hardness is 140HV 0.2 . The yield strength at room temperature is 288MPa, and the tensile strength exceeds 315MPa. At the same time, the yield strength of the unheated part at 200℃ is 235MPa, and the tensile strength is 254MPa. The alloy of Comparative Example 2 lacks Sc, Zr, and Si, and the performance is poorer than that of Example 1.

[0088] Comparative Example 3

[0089] The difference between Comparative Example 3 and Example 1 is that the 3D printing process in step (6) is different, specifically: the substrate heating temperature during printing is increased to 150℃; the printing process is: laser power 400W; scanning speed 1200mm / s; scanning interval 0.1mm; scanning layer thickness 0.05mm; and the scanning strategy is that the rotation angle between adjacent layers is 67°, and a multi-component high-entropy aluminum alloy sample is obtained.

[0090] The obtained multi-component high-entropy aluminum alloy sample was subjected to the same performance test as in Example 1. The metallurgical defects increased under the light microscope, obvious holes and micro-cracks appeared, the sample density reached 97%, and the average hardness was only 120 HV 0.2 The yield strength at room temperature was 245 MPa, and the tensile strength was only 269 MPa. At the same time, the yield strength of the unheated part at 200°C was only 189 MPa, and the tensile strength was 205 MPa.

[0091] Comparative Example 4

[0092] The difference between Comparative Example 4 and Example 1 is that the mass percentage content of the metal powder in step (1) is different, and the composition is as follows: Er: 0.3wt%; Fe: 5.5wt%; Cr: 5wt%; Mn: 5wt%; Ni: 5.5wt%; Sc: 1.1wt%, Zr: 1.3wt%; Si: 1.2wt%, and the rest is Al. The other steps are the same as in Example 1, and a multi-component high-entropy aluminum alloy sample is obtained.

[0093] The obtained multi-component high-entropy aluminum alloy sample was subjected to the same performance test as in Example 1. In the density test, the density reached 99.35%, and the average hardness was 149 HV 0.2 . The yield strength at room temperature was 295 MPa, and the tensile strength was 355 MPa. At the same time, the yield strength of the unheated part at 200°C was 244 MPa, and the tensile strength was 261 MPa.

[0094] Comparative Example 5

[0095] The difference between Comparative Example 5 and Example 1 is that the mass percentage content of the metal powder in step (1) is different, and the composition is as follows: Er: 3wt%; Sc: 0.05wt%, Zr: 0.1wt%; Si: 0.05wt%, and the rest is Al. The other steps are the same as in Example 1, and a multi-component high-entropy aluminum alloy sample is obtained.

[0096] The obtained multi-component high-entropy aluminum alloy sample was subjected to the same performance test as in Example 1. In the density test, the density reached 99.2%, and the average hardness was 149.4 HV 0.2 . The yield strength at room temperature was 297 MPa, and the tensile strength was 356.5 MPa. At the same time, the yield strength of the unheated part at 200°C was 246.5 MPa, and the tensile strength was 265.4 MPa.

[0097] Comparative Example 6

[0098] The difference between the present comparative example 6 and the example 1 is that the mass percentage content of the metal powder configured in step (1) is different, and the composition is as follows: Er: 3wt%; Fe: 0.9wt%; Cr: 0.8wt%; Mn: 0.4wt%; Ni: 0.45wt%; Sc: 1.1wt%, Zr: 1.3wt%; Si: 1.2wt%, and the rest is Al. The other steps are the same as those in the example 1, and a multi-component high-entropy aluminum alloy sample is obtained.

[0099] The obtained multi-component high-entropy aluminum alloy sample is subjected to the same performance test as in the example 1, and in the density test, the density reaches 99.1%, and the average hardness is 145HV 0.2 . The yield strength at room temperature is 294MPa, and the tensile strength is 348MPa. At the same time, the yield strength of the unheated part at 200℃ is 239MPa, and the tensile strength is 259.3MPa.

[0100] Comparative example 7

[0101] The difference between the present comparative example 7 and the example 1 is that the mass percentage content of the metal powder configured in step (1) is different, and the composition is as follows: Er: 5wt%; Fe: 5.5wt%; Cr: 5wt%; Mn: 5wt%; Ni: 5.5wt%; Sc: 1.1wt%, Zr: 1.3wt%; Si: 1.2wt%, and the rest is Al. The other steps are the same as those in the example 1, and a multi-component high-entropy aluminum alloy sample is obtained.

[0102] The obtained multi-component high-entropy aluminum alloy sample is subjected to the same performance test as in the example 1, and in the density test, the density reaches 99.25%, and the average hardness is 139HV 0.2 . The yield strength at room temperature is 285MPa, and the tensile strength is 338MPa. At the same time, the yield strength of the unheated part at 200℃ is 245MPa, and the tensile strength is 269.3MPa.

[0103] The alloy composition of the present application has reduced metallurgical defects after laser 3D printing, high density, and the comprehensive performance is better than that of the existing additive manufacturing aluminum alloy, especially the high-temperature tensile strength. The common additive manufacturing Al-Si series, 2000 series and 7000 series aluminum alloy has a maximum tensile strength of only 147MPa at 200℃. The alloy composition of the present application has low anisotropy after laser 3D printing, and the alloy is dense and does not crack, solving the problem of low high-temperature mechanical properties of the existing additive manufacturing aluminum alloy, and also overcoming the common problem of thermal cracking of the additive manufacturing aluminum alloy.

[0104] The present application is around the problem that the mechanical properties of the existing additive manufacturing aluminum alloy are significantly reduced, the strength and hardness are poor, and the creep resistance is low, and innovatively proposes a rare earth modified additive manufacturing high-entropy aluminum-based alloy, and Er, Fe, Cr, Mn, Ni, Sc, Zr and Si elements are added in the high-entropy aluminum-based alloy, so that the high-entropy aluminum-based alloy is used in the 3D printing process, and the super-saturated solid solution of the elements in the high-entropy aluminum alloy is realized by using the selective laser melting technology, and the multi-scale synergistic strengthening is realized.

[0105] The present application has four core effects. The high-entropy effect in thermodynamics can significantly reduce the free energy of the system, increase the mutual solid solubility between components, reduce the driving force of ordering and segregation, and prevent the formation of ordered phases or intermetallic compounds due to phase separation; the serious lattice distortion effect, the effect of solid solution strengthening makes the mechanical properties higher, and at the same time the thermal conductivity and electrical conductivity are reduced, and the x-ray scattering is also increased; the diffusion retardation effect in dynamics, the serious lattice distortion hinders the movement of atoms, so that the diffusion speed of elements is slow. The diffusion retardation effect can reduce the nucleation and growth rate and improve the microstructure stability; the cocktail effect has excellent comprehensive performance, the cocktail effect was first proposed by Indian scientist Ranganathan, which means that the comprehensive performance of the alloy not only reflects the characteristics of each element, but also has a special effect beyond the mixing principle. Lattice distortion leads to high strength, and the difference in atomic radius can intensify the lattice distortion, increase the pining force required for dislocation slip, and significantly improve the strength of the alloy.

[0106] In summary, by adding appropriate percentages of Er, Fe, Cr, Mn, Ni, Sc, Zr and Si elements in the rare earth modified additive manufacturing high-entropy aluminum-based alloy, the cracking sensitivity of the 3D printed high-entropy aluminum-based alloy is greatly reduced, the mechanical properties at high temperature are excellent, the metallurgical defects are low, the density is high, the high thermal stability and the endurance strength are high. The Er element plays a modification role in the aluminum alloy, so that the grain size of the high-entropy aluminum-based alloy is smaller, fine-grain strengthening is generated, and the strength and hardness of the aluminum alloy can be greatly improved. The elements Fe, Cr, Mn and Ni have low solid solubility and small diffusion coefficient, can generate precipitated particles in the alloy, and the coarsening speed of the particles is slow, and the fast cooling characteristics of additive manufacturing can promote the generation of uniform and dispersed fine precipitated phase, produce precipitation strengthening, hinder dislocation slip, inhibit grain boundary sliding and vacancy diffusion, thereby improving the high temperature strength of the aluminum alloy, which is proved by the experimental results of example one and example two and four;

[0107] The trace amounts of Sc and Zr form low-volume fraction Al3(Sc, Zr) nanophase, Figure 4It can be observed that there are a large number of fine grain regions at the boundary of the molten pool, which can illustrate that the dispersion strengthening of Al3(Sc, Zr) particles can significantly refine the grains. And after heat treatment, these particles are dispersed in the matrix, which is fully coherent with the matrix crystal structure, so it can effectively inhibit recrystallization, thereby improving the strength of the alloy. The effect of adding Si is to form a high volume fraction of sub-micron dispersed phase. Because the dispersed phase has high thermal stability, dispersion strengthening is an effective strengthening method, especially when the alloy is in a high temperature environment, which can be proved by the experimental results of example one and example three;

[0108] Therefore, it can be proved that the rare earth modified additive manufacturing high-entropy aluminum-based alloy improves the mechanical properties of the alloy through the synergistic effect of the three strengthening mechanisms.

[0109] It should be noted that the above examples are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application, which should be covered in the scope of the claims of the present application.

Claims

1. A rare-earth modified additive manufacturing method for high-entropy aluminum-based alloy powder, characterized in that: The alloy powder is a pre-alloyed powder, expressed as a percentage by mass. Including, Er: 0.5~3 wt%; Fe: 2.5~5.5 wt%; Cr: 2~5 wt%; Mn: 2~5 wt%; Ni: 2.5~5.5 wt%; Sc: 0.1~1.1 wt%, Zr: 0.3~1.3 wt%; Si: 0.2~1.2 wt%, and the rest is Al.

2. The rare-earth modified additive manufacturing of high-entropy aluminum-based alloy powder as described in claim 1, characterized in that: In terms of mass percentage, Including, Er: 3 wt%; Fe: 5.5 wt%; Cr: 5 wt%; Mn: 5 wt%; Ni: 5.5 wt%; Sc: 1.1 wt%, Zr: 1.3 wt%; Si: 1.2 wt%, and the rest is Al.

3. The method for preparing rare earth modified additive manufacturing high-entropy aluminum-based alloy powder as described in claim 1 or 2, characterized in that: include, Prepare the metal powder according to the stated mass percentage content; Vacuum melting: The prepared metal powder is melted under vacuum. Atomization powdering is performed after vacuum melting to obtain rare earth modified additive manufacturing high-entropy aluminum-based alloy powder.

4. The method for preparing rare earth-modified additive manufacturing of high-entropy aluminum-based alloy powder as described in claim 3, characterized in that: The vacuum melting process is carried out at a melting temperature of 600~850 ℃ and a gas pressure of 0.5~0.6 MPa in the melting furnace; the atomization powdering process is carried out at a gas atomization pressure of 4~5.5 MPa.

5. The application of rare earth modified additive manufacturing high-entropy aluminum-based alloy powder as described in claim 1 or 2 in 3D printing.

6. A method for preparing rare earth-modified additive manufacturing high-entropy aluminum-based alloys, characterized in that: include, The rare earth modified additive manufacturing high-entropy aluminum-based alloy powder as described in claim 1 or 2 is subjected to sieving and drying. After processing, it is 3D printed.

7. The method for preparing rare earth-modified additive manufacturing of high-entropy aluminum-based alloys as described in claim 6, characterized in that: The process involves sieving, and the resulting alloy powder has a particle size of 15~53 μm. The 3D printing is laser powder bed 3D printing, with a laser power of 200~400 W, a scanning speed of 500~1200 mm / s, a scanning spacing of 0.04~0.14 mm, a scanning layer thickness of 0.03~0.05 mm, and a scanning strategy of rotating the adjacent layers by 67°.

8. The method for preparing rare earth-modified additive manufacturing high-entropy aluminum-based alloys as described in claim 6, characterized in that: It also includes, Heat treatment: After 3D printing, heat treatment is performed to obtain the printed product; The heat treatment temperature is 300~325 ℃, the heating rate is 50 ℃ / min, and the holding time is 5~6h.

9. The rare-earth modified additive manufacturing high-entropy aluminum-based alloy obtained by the preparation method according to claim 6 or 7, characterized in that: The alloy has the following properties: (a) Room temperature yield strength 299~343 MPa, elongation over 4%, tensile strength 359~403 MPa; (b) Yield strength at 200 ℃: 246~295 MPa, tensile strength: 266~312 MPa; yield strength at 250 ℃: 215~265 MPa, tensile strength: 224~272 MPa, elongation: 8~10%.

10. The rare-earth modified additive manufacturing high-entropy aluminum-based alloy obtained by the preparation method according to claim 8, characterized in that: The alloy has the following properties: After heat treatment, the room temperature tensile strength reaches 440~482 MPa.

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