Method for improving mechanical properties of additive manufactured high strength aluminum alloys containing scandium

Abstract

This invention relates to the field of metals, and particularly to a method for improving the mechanical properties of additively manufactured high-strength aluminum alloys containing Sc. The method provided by this invention involves first heat-treating the additively manufactured high-strength aluminum alloy part containing Sc, then subjecting the part obtained in step 1 to cryogenic treatment, followed by heat treatment of the part obtained in step 2, then cryogenic treatment of the part obtained in step 3, and finally heat treatment of the part obtained in step 4. Through these specific processing steps and certain process conditions, this invention can effectively improve the mechanical properties of additively manufactured high-strength aluminum alloy materials containing Sc.

Description

Technical Field

[0001] This invention relates to the field of metals, and in particular to a method for improving the mechanical properties of additively manufactured high-strength aluminum alloys containing Sc. Background Technology

[0002] High-strength aluminum alloys are lightweight structural materials with low density and high specific strength, and are widely used in aviation, aerospace, and automotive fields. With the increasing demand for lightweight equipment, high-strength aluminum alloy parts are becoming increasingly complex, and traditional processing methods such as casting and forging are gradually becoming insufficient for manufacturing complex high-strength aluminum alloy parts.

[0003] Additive manufacturing is a near-net-shape forming process that eliminates the need for molds. Specifically, additive manufacturing, also known as 3D printing, is an emerging manufacturing technology that uses digital models as a basis to build up material layer by layer to create physical objects. Simply put, it's a manufacturing technology that uses digital models to build up material layer by layer to form a three-dimensional object. Compared to traditional casting and forging processes, additive manufacturing is more suitable for the rapid, high-quality manufacturing of complex structural parts.

[0004] Traditional high-strength aluminum alloys are mainly Al-Cu and Al-Zn alloys. These alloys have high alloying element content and a wide solidification temperature range, making them prone to cracking during additive manufacturing. To address this issue, high-strength aluminum alloys containing Sc (Sc) specifically for additive manufacturing have been developed. The addition of Sc improves the formability of the alloy during additive manufacturing and can also form a coherent strengthening phase, Al3(Sc, Zr), with the aluminum matrix. Al3(Sc, Zr) particles not only act as heterogeneous nucleation sites during molten pool solidification, greatly promoting grain refinement, but also produce a significant precipitation strengthening effect, improving the mechanical properties of the material. However, the mechanical properties of Sc-containing high-strength aluminum alloys after additive manufacturing are relatively low. Summary of the Invention

[0005] In view of this, the present invention provides a method for improving the mechanical properties of additively manufactured high-strength aluminum alloys containing Sc. The method provided by the present invention can effectively improve the mechanical properties of additively manufactured high-strength aluminum alloys containing Sc.

[0006] This invention provides a method for improving the mechanical properties of additively manufactured high-strength aluminum alloys containing silica, comprising the following steps:

[0007] Step 1: Heat treat the additively manufactured high-strength aluminum alloy parts containing Sc;

[0008] Step 2: Perform deep cryogenic treatment on the parts obtained in Step 1;

[0009] Step 3: Perform heat treatment on the parts obtained in Step 2;

[0010] Step 4: Perform deep cryogenic treatment on the parts obtained in Step 3;

[0011] Step 5: Perform heat treatment on the part obtained in Step 4;

[0012] in,

[0013] In step 1, the temperature of the heat treatment is 260–360°C;

[0014] In step 2, the cryogenic treatment involves cooling to ≤-130℃;

[0015] In step 3, the temperature of the heat treatment is 260–340°C;

[0016] In step 4, the cryogenic treatment involves cooling to ≤-130℃;

[0017] In step 5, the temperature of the heat treatment is 260–340°C.

[0018] Preferably, in step 1, the heating rate of the heat treatment is ≤30℃ / min, and the holding time is ≥1h.

[0019] Preferably, in step 2, the cooling rate of the cryogenic treatment is ≤10℃ / min, and the holding time is ≥24h.

[0020] Preferably, in step 3, the heating rate of the heat treatment is ≤30℃ / min, and the holding time is ≥1h.

[0021] Preferably, in step 4, the cooling rate of the cryogenic treatment is ≤10℃ / min, and the holding time is ≥24h.

[0022] Preferably, in step 5, the heating rate of the heat treatment is ≤30℃ / min, and the holding time is ≥1h.

[0023] Preferably, in step 1, the heat treatment process includes: heating from room temperature to 260-360°C at a heating rate of 20±10°C / min, holding at that temperature for 1-10 hours, and then air cooling to room temperature.

[0024] Preferably, in step 2, the cryogenic treatment process includes: cooling to -130 to -180°C at a cooling rate of 5 to 10°C / min, holding at that temperature for 24 to 48 hours, and then heating back to room temperature.

[0025] Preferably, in step 3, the heat treatment process includes: heating from room temperature to 260-340°C at a heating rate of 20±10°C / min, holding at that temperature for 1-6 hours, and then air cooling to room temperature.

[0026] Preferably, in step 4, the cryogenic treatment process includes: cooling to -130 to -180°C at a cooling rate of 5 to 10°C / min, holding at that temperature for 24 to 48 hours, and then heating back to room temperature;

[0027] In step 5, the heat treatment process includes: heating from room temperature to 260-340°C at a heating rate of 20±10°C / min, holding at that temperature for 1-6 hours, and then air cooling to room temperature.

[0028] This invention provides a method for improving the mechanical properties of additively manufactured high-strength aluminum alloy containing Sc. First, the additively manufactured high-strength aluminum alloy part containing Sc is heat-treated. Then, the part obtained in step 1 is cryogenically treated. Next, the part obtained in step 2 is heat-treated. Then, the part obtained in step 3 is cryogenically treated. Finally, the part obtained in step 4 is heat-treated. This invention, through step 1, promotes the precipitation of Al3(Sc, Zr) particles from the α-Al matrix, forming a large amount of Al3(Sc, Zr) coherent with the matrix; simultaneously, it eliminates the internal stress generated in the parts during additive manufacturing, preventing material cracking. Steps 2 and 4 involve two deep cryogenic treatments, creating numerous solute atom-rich regions, providing more nucleation centers for subsequent heat treatment, and laying the foundation for the precipitation of more dispersed, fine Al3(Sc, Zr) particles, thereby improving the mechanical properties of additively manufactured Sc-containing high-strength aluminum alloys. Following the two deep cryogenic treatments in steps 2 and 4, a heat treatment is performed, which further promotes the precipitation of Al3(Sc, Zr) particles from the α-Al matrix, forming coherent Al3(Sc, Zr) coherent with the matrix, thus improving the material's mechanical properties. This invention, through the above specific treatment steps and certain process conditions, can effectively improve the problems of easy cracking and low mechanical properties in Sc-containing high-strength aluminum alloys after additive manufacturing. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the processing flow of the method of the present invention. Detailed Implementation

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0032] In this article, the technical features described in an open-ended manner include both closed technical solutions composed of the listed features and open technical solutions that include the listed features.

[0033] In this document, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when a range refers to an integer, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0034] In this article, when referring to units for data ranges, if the unit is only followed by the right endpoint, it indicates that the units for the left and right endpoints are the same. For example, 260~360℃ means that the units for the left endpoint "260" and the right endpoint "360" are both in degrees Celsius (℃).

[0035] This document only specifically discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, just as any upper limit can be combined with any other upper limit to form an unspecified range. Furthermore, each individually disclosed point or single value can itself serve as a lower or upper limit and be combined with any other point or single value or with other lower or upper limits to form an unspecified range.

[0036] In this article, room temperature refers to ambient temperature. This invention does not have any special restrictions on this; it can be any normal room temperature, specifically 0–40°C.

[0037] This invention provides a method for improving the mechanical properties of additively manufactured high-strength aluminum alloys containing silica, comprising the following steps:

[0038] Step 1: Heat treat the additively manufactured high-strength aluminum alloy parts containing Sc;

[0039] Step 2: Perform deep cryogenic treatment on the parts obtained in Step 1;

[0040] Step 3: Perform heat treatment on the parts obtained in Step 2;

[0041] Step 4: Perform deep cryogenic treatment on the parts obtained in Step 3;

[0042] Step 5: Perform heat treatment on the part obtained in Step 4;

[0043] in,

[0044] In step 1, the temperature of the heat treatment is 260–360°C;

[0045] In step 2, the cryogenic treatment involves cooling to ≤-130℃;

[0046] In step 3, the temperature of the heat treatment is 260–340°C;

[0047] In step 4, the cryogenic treatment involves cooling to ≤-130℃;

[0048] In step 5, the temperature of the heat treatment is 260–340°C.

[0049] [Regarding step 1]:

[0050] Step 1: Heat treat the additively manufactured high-strength aluminum alloy parts containing Sc.

[0051] In this invention, the additively manufactured high-strength aluminum alloy parts containing silica (Sc) refer to parts produced using Sc-containing high-strength aluminum alloys as raw materials through additive manufacturing processes. The Sc-containing high-strength aluminum alloy is a Sc-containing high-strength aluminum alloy specifically designed for additive manufacturing; its type is not particularly limited and can be any conventional Sc-containing high-strength aluminum alloy used in additive manufacturing in the field. More specifically, the Sc-containing high-strength aluminum alloy is an aluminum alloy with a tensile strength > 400 MPa; preferably, it is an AlMgSc high-strength aluminum alloy or an AlMnSc high-strength aluminum alloy. The AlMgSc high-strength aluminum alloy includes, but is not limited to, Al4.5Mg0.55Sc alloy, Al7.5Mg0.65Sc alloy, and Al5.5Mg0.8Sc. The AlMnSc high-strength aluminum alloy includes, but is not limited to, Al7Mn0.6Sc alloy and Al4Mn0.65Sc alloy.

[0052] In this invention, the additively manufactured high-strength aluminum alloy parts containing Sc are first subjected to heat treatment.

[0053] In this invention, the heat treatment temperature is 260–360°C, specifically 260°C, 270°C, 280°C, 290°C, 300°C, 310°C, 320°C, 330°C, 340°C, 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, and 360°C. This invention controls the temperature within the above range to effectively strengthen the material. If the temperature is below 260°C, Al3(Sc, Zr) particles will not precipitate, failing to achieve the purpose of enhancing the mechanical properties of the material. If the temperature is above 360°C, it will lead to severe grain growth, damaging the mechanical properties of the material.

[0054] In this invention, the heating rate of the heat treatment is preferably ≤30℃ / min, more preferably 20±10℃ / min, and specifically can be 10℃ / min, 15℃ / min, 20℃ / min, 25℃ / min, or 30℃ / min. This invention controls the heating rate at the above-mentioned levels to ensure production efficiency while avoiding / reducing material cracking. If the heating rate exceeds 30℃ / min, it will lead to excessive stress, easily causing material cracking.

[0055] In this invention, the heat treatment holding time is preferably ≥1 hour, more preferably 1 to 10 hours, specifically 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, and 10 hours. This invention controls the heat treatment to the above-mentioned holding time to ensure both production efficiency and effective material strengthening. If the holding time is less than 1 hour, the Al3(Sc, Zr) particles will not precipitate sufficiently, failing to strengthen the material.

[0056] In this invention, the heat treatment process preferably includes: heating from room temperature to 260–360°C at a heating rate of 20 ± 10°C / min, holding at that temperature for 1–10 hours, and then air cooling to room temperature. In this invention, the above heat treatment process can be carried out in a heating furnace, i.e., the parts are placed in a heating furnace for heat treatment.

[0057] The present invention, through the treatment in step 1, can promote the precipitation of Al3(Sc, Zr) particles from the α-Al matrix, forming a large amount of Al3(Sc, Zr) coherent with the matrix. At the same time, it eliminates the internal stress generated in the parts during additive manufacturing, preventing material cracking.

[0058] [Regarding step 2]:

[0059] Step 2: Perform deep cryogenic treatment on the parts obtained in Step 1.

[0060] In this invention, the target temperature for cryogenic treatment is ≤-130℃, more preferably -130 to -180℃, specifically -130℃, -140℃, -150℃, -160℃, -170℃, or -180℃. If the temperature is higher than -130℃, the cryogenic treatment effect will be poor and the mechanical properties cannot be effectively improved.

[0061] In this invention, the cooling rate of the cryogenic treatment is preferably ≤10℃ / min, more preferably 5~10℃ / min, specifically 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, or 10℃ / min. If the cooling rate is greater than 10℃ / min, cooling stress and thermal stress may be generated, causing material cracking.

[0062] In this invention, the cryogenic treatment holding time is preferably ≥24h, more preferably 24~48h, specifically 24h, 26h, 28h, 30h, 32h, 34h, 36h, 38h, 40h, 42h, 44h, 46h, and 48h. If the holding time is less than 24h, the mechanical properties cannot reach their optimal level; if the holding time is longer than 48h, the processing time will be extended, reducing production efficiency.

[0063] In this invention, the cryogenic treatment process preferably includes: cooling to -130 to -180°C at a cooling rate of 5 to 10°C / min, holding at that temperature for 24 to 48 hours, and then warming to room temperature. In this invention, the cryogenic treatment can be performed in a cryogenic control chamber, i.e., the parts processed in step 1 are placed in the cryogenic control chamber for cryogenic treatment. After the holding period, the parts are removed and placed in air to warm to room temperature.

[0064] For additive manufacturing alloys, the rapid cooling rate during the additive manufacturing process results in smaller grain sizes and better mechanical properties in the formed material. However, after heat treatment, the grain size may increase, leading to a decrease in mechanical properties. Therefore, this invention performs two cycles of deep cryogenic treatment after the heat treatment in step 1 (set in steps 2 and 4 respectively). These two deep cryogenic treatment processes promote grain refinement, and the low temperature causes the alloy lattice to shrink, the lattice constant to decrease, and the grains to rotate, increasing the dislocation density in the material, promoting twin formation, and thus forming more solute atom enrichment regions. This provides more nucleation centers for subsequent heat treatment, laying the foundation for the precipitation of more dispersed, fine Al3(Sc, Zr) particles, thereby improving the mechanical properties of the material.

[0065] [Regarding step 3]:

[0066] Step 3: Perform heat treatment on the parts obtained in Step 2.

[0067] In this invention, the heat treatment temperature is 260-340℃, specifically 260℃, 270℃, 280℃, 290℃, 300℃, 310℃, 320℃, 330℃, 340℃, 300℃, 310℃, 320℃, 330℃, and 340℃.

[0068] In this invention, the heating rate of the heat treatment is preferably ≤30℃ / min, more preferably 20±10℃ / min, and specifically can be 10℃ / min, 15℃ / min, 20℃ / min, 25℃ / min, or 30℃ / min.

[0069] In this invention, the heat treatment holding time is preferably ≥1h, more preferably 1 to 6h, specifically 1h, 2h, 3h, 4h, 5h, or 6h.

[0070] In this invention, the heat treatment process preferably includes: heating from room temperature to 260–340°C at a heating rate of 20 ± 10°C / min, holding at that temperature for 1–6 hours, and then air cooling to room temperature. In this invention, the above heat treatment process can be carried out in a heating furnace, i.e., the parts are placed in a heating furnace for heat treatment.

[0071] [Regarding step 4]:

[0072] Step 4: Perform deep cryogenic treatment on the parts obtained in Step 3.

[0073] In this invention, the target temperature for the cryogenic treatment is ≤-130℃, more preferably -130 to -180℃, specifically -130℃, -140℃, -150℃, -160℃, -170℃, or -180℃.

[0074] In this invention, the cooling rate of the cryogenic treatment is preferably ≤10℃ / min, more preferably 5~10℃ / min, specifically 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, or 10℃ / min.

[0075] In this invention, the cryogenic treatment holding time is preferably ≥24h, more preferably 24~48h, specifically 24h, 26h, 28h, 30h, 32h, 34h, 36h, 38h, 40h, 42h, 44h, 46h, or 48h. If the holding time is less than 24h...

[0076] In this invention, the cryogenic treatment process preferably includes: cooling to -130 to -180°C at a cooling rate of 5 to 10°C / min, holding at that temperature for 24 to 48 hours, and then warming to room temperature. In this invention, the cryogenic treatment can be performed in a cryogenic control chamber, i.e., the parts are placed in the cryogenic control chamber for cryogenic treatment. After the holding period, the parts are removed and placed in air to warm to room temperature.

[0077] This invention uses two deep cryogenic treatments to form more solute atom enrichment regions, providing more nucleation centers for subsequent heat treatment and laying the foundation for the precipitation of more dispersed and fine Al3(Sc, Zr) particles, thereby improving the mechanical properties of additively manufactured high-strength aluminum alloys containing Sc.

[0078] [Regarding step 5]:

[0079] Step 5: Perform heat treatment on the part obtained in Step 4.

[0080] In this invention, the heat treatment temperature is 260-340℃, specifically 260℃, 270℃, 280℃, 290℃, 300℃, 310℃, 320℃, 330℃, 340℃, 300℃, 310℃, 320℃, 330℃, and 340℃.

[0081] In this invention, the heating rate of the heat treatment is preferably ≤30℃ / min, more preferably 20±10℃ / min, and specifically can be 10℃ / min, 15℃ / min, 20℃ / min, 25℃ / min, or 30℃ / min.

[0082] In this invention, the heat treatment holding time is preferably ≥1h, more preferably 1 to 6h, specifically 1h, 2h, 3h, 4h, 5h, or 6h.

[0083] In this invention, the heat treatment process preferably includes: heating from room temperature to 260–340°C at a heating rate of 20 ± 10°C / min, holding at that temperature for 1–6 hours, and then air cooling to room temperature. In this invention, the above heat treatment process can be carried out in a heating furnace, i.e., the parts are placed in a heating furnace for heat treatment.

[0084] Steps 3 and 5 of this invention involve a second heat treatment following the two cryogenic treatments in steps 2 and 4. These two heat treatments promote the precipitation of Al3(Sc, Zr) particles from the α-Al matrix, forming Al3(Sc, Zr) coherent with the matrix, thereby improving the material's mechanical properties. The reasons for the parameter selection in steps 3 and 5 are the same as those in step 1, but cryogenic treatment promotes the precipitation of Al3(Sc, Zr) particles, allowing the upper limit of the holding temperature to be reduced to 340℃ and the upper limit of the holding time to be reduced to 6 hours. This invention performs a first heat treatment followed by a cryogenic-heat treatment cycle, repeating this process twice to optimize the product's mechanical properties. The processing flow of this invention is as follows: Figure 1 As shown.

[0085] This invention provides a method for improving the mechanical properties of additively manufactured high-strength aluminum alloy containing Sc. First, the additively manufactured high-strength aluminum alloy part containing Sc is heat-treated. Then, the part obtained in step 1 is cryogenically treated. Next, the part obtained in step 2 is heat-treated. Then, the part obtained in step 3 is cryogenically treated. Finally, the part obtained in step 4 is heat-treated. This invention, through step 1, promotes the precipitation of Al3(Sc, Zr) particles from the α-Al matrix, forming a large amount of Al3(Sc, Zr) coherent with the matrix; simultaneously, it eliminates the internal stress generated in the parts during additive manufacturing, preventing material cracking. Steps 2 and 4 involve two deep cryogenic treatments, creating numerous solute atom-rich regions, providing more nucleation centers for subsequent heat treatment, and laying the foundation for the precipitation of more dispersed, fine Al3(Sc, Zr) particles, thereby improving the mechanical properties of additively manufactured Sc-containing high-strength aluminum alloys. Following the two deep cryogenic treatments in steps 2 and 4, a heat treatment is performed, which further promotes the precipitation of Al3(Sc, Zr) particles from the α-Al matrix, forming coherent Al3(Sc, Zr) coherent with the matrix, thus improving the material's mechanical properties. This invention, through the above specific treatment steps and certain process conditions, can effectively improve the problems of easy cracking and low mechanical properties in Sc-containing high-strength aluminum alloys after additive manufacturing.

[0086] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0087] Example 1

[0088] Step 1: Place the additively manufactured AlMgSc high-strength aluminum alloy (specifically Al4.5Mg0.55Sc alloy) parts into a heating furnace for heat treatment. Heat the parts from room temperature to 360°C in the furnace at a heating rate of 10°C / min and hold for 3 hours. Then air cool to room temperature.

[0089] Step 2: Place the parts processed in Step 1 into a cryogenic control chamber for cryogenic treatment. Cool to -140℃ at a cooling rate of 5℃ / min, hold for 26 hours, then remove and place in air to warm to room temperature.

[0090] Step 3: Place the parts processed in Step 2 into a heating furnace for heat treatment. Heat the parts from room temperature to 340°C at a heating rate of 20°C / min and hold for 1 hour. Then air cool to room temperature.

[0091] Step 4: Place the parts processed in Step 3 into a cryogenic control chamber for cryogenic treatment. Cool to -140℃ at a cooling rate of 5℃ / min, hold for 26 hours, then remove and place in air to warm to room temperature.

[0092] Step 5: Place the parts processed in Step 4 into a heating furnace for heat treatment. Heat the parts from room temperature to 340°C at a heating rate of 20°C / min and hold for 1 hour. Then air cool to room temperature.

[0093] Example 2

[0094] Step 1: Place the additively manufactured AlMgSc high-strength aluminum alloy (specifically Al7.5Mg0.65Sc alloy) parts into a heating furnace for heat treatment. Heat the parts from room temperature to 260°C in the furnace at a heating rate of 20°C / min and hold for 10 hours. Then air cool to room temperature.

[0095] Step 2: Place the parts processed in Step 1 into a cryogenic control chamber for cryogenic treatment. Cool to -130°C at a cooling rate of 5°C / min, hold for 48 hours, then remove and place in air to warm to room temperature.

[0096] Step 3: Place the parts processed in Step 2 into a heating furnace for heat treatment. Heat the parts from room temperature to 300°C at a heating rate of 30°C / min and hold for 2 hours. Then air cool to room temperature.

[0097] Step 4: Place the parts processed in Step 3 into a cryogenic control chamber for cryogenic treatment. Cool to -130°C at a cooling rate of 5°C / min, hold for 48 hours, then remove and place in air to warm to room temperature.

[0098] Step 5: Place the parts processed in Step 4 into a heating furnace for heat treatment. Heat the parts from room temperature to 300°C at a heating rate of 30°C / min and hold for 2 hours. Then air cool to room temperature.

[0099] Example 3

[0100] Step 1: Place the additively manufactured AlMgSc high-strength aluminum alloy (specifically Al5.5Mg0.8Sc alloy) parts into a heating furnace for heat treatment. Heat the parts from room temperature to 360°C in the furnace at a heating rate of 30°C / min and hold for 1 hour. Then air cool to room temperature.

[0101] Step 2: Place the parts processed in Step 1 into a cryogenic control chamber for cryogenic treatment. Cool to -180°C at a cooling rate of 10°C / min, hold for 24 hours, then remove and place in air to warm to room temperature.

[0102] Step 3: Place the parts processed in Step 2 into a heating furnace for heat treatment. Heat the parts from room temperature to 260°C at a heating rate of 10°C / min and hold for 6 hours. Then air cool to room temperature.

[0103] Step 4: Place the parts processed in Step 3 into a cryogenic control chamber for cryogenic treatment. Cool to -180°C at a cooling rate of 10°C / min, hold for 24 hours, then remove and place in air to warm to room temperature.

[0104] Step 5: Place the parts processed in Step 4 into a heating furnace for heat treatment. Heat the parts from room temperature to 260°C at a heating rate of 10°C / min and hold for 6 hours. Then air cool to room temperature.

[0105] Example 4

[0106] Step 1: Place the additively manufactured AlMnSc high-strength aluminum alloy (specifically Al7Mn0.6Sc alloy) parts into a heating furnace for heat treatment. Heat the parts from room temperature to 310°C in the furnace at a heating rate of 15°C / min and hold for 8 hours. Then air cool to room temperature.

[0107] Step 2: Place the parts processed in Step 1 into a cryogenic control chamber for cryogenic treatment. Cool to -160°C at a cooling rate of 8°C / min, hold for 24 hours, then remove and place in air to warm to room temperature.

[0108] Step 3: Place the parts processed in Step 2 into a heating furnace for heat treatment. Heat the parts from room temperature to 290°C at a heating rate of 30°C / min and hold for 5 hours. Then air cool to room temperature.

[0109] Step 4: Place the parts processed in Step 3 into a cryogenic control chamber for cryogenic treatment. Cool to -160°C at a cooling rate of 8°C / min, hold for 24 hours, then remove and place in air to warm to room temperature.

[0110] Step 5: Place the parts processed in Step 4 into a heating furnace for heat treatment. Heat the parts from room temperature to 290°C at a heating rate of 30°C / min and hold for 5 hours. Then air cool to room temperature.

[0111] Example 5

[0112] Step 1: Place the additively manufactured AlMnSc high-strength aluminum alloy (specifically Al4Mn0.65Sc alloy) parts into a heating furnace for heat treatment. Heat the parts from room temperature to 360°C in the furnace at a heating rate of 10°C / min and hold for 1 hour. Then air cool to room temperature.

[0113] Step 2: Place the parts processed in Step 1 into a cryogenic control chamber for cryogenic treatment. Cool to -160°C at a cooling rate of 5°C / min, hold for 30 hours, then remove and place in air to warm to room temperature.

[0114] Step 3: Place the parts processed in Step 2 into a heating furnace for heat treatment. Heat the parts from room temperature to 310°C at a heating rate of 30°C / min and hold for 4 hours. Then air cool to room temperature.

[0115] Step 4: Place the parts processed in Step 3 into a cryogenic control chamber for cryogenic treatment. Cool to -160°C at a cooling rate of 5°C / min, hold for 30 hours, then remove and place in air to warm to room temperature.

[0116] Step 5: Place the parts processed in Step 4 into a heating furnace for heat treatment. Heat the parts from room temperature to 310°C at a heating rate of 30°C / min and hold for 4 hours. Then air cool to room temperature.

[0117] The room temperature tensile strength of the alloy materials obtained in Examples 1-5 was tested and compared with the room temperature tensile strength of the precipitated alloys (i.e., alloys that were not treated by the method of this invention after additive manufacturing). The results are shown in Table 1.

[0118] Table 1: Mechanical Properties of Materials

[0119] Alloy strength after treatment by the method in the example, MPa Deposited alloy strength, MPa Example 1 519 367 Example 2 531 357 Example 3 545 361 Example 4 522 344 Example 5 497 325

[0120] The test results above show that, compared with the deposited alloy, the alloy material treated by the method of the present invention has significantly improved tensile strength.

[0121] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of these embodiments are merely to aid in understanding the method and core ideas of the present invention, including the best mode, and to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims. The scope of protection of this patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements similar to those expressed in the claims, or if they include equivalent structural elements that are not substantially different from those expressed in the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. A method for improving the mechanical properties of additively manufactured high-strength aluminum alloys containing Sc, characterized in that, Includes the following steps: Step 1: Heat treat the additively manufactured high-strength aluminum alloy parts containing Sc; Step 2: Perform deep cryogenic treatment on the parts obtained in Step 1; Step 3: Perform heat treatment on the parts obtained in Step 2; Step 4: Perform deep cryogenic treatment on the parts obtained in Step 3; Step 5: Perform heat treatment on the part obtained in Step 4; in, In step 1, the temperature of the heat treatment is 260–360°C; In step 2, the cryogenic treatment involves cooling to ≤-130℃; In step 3, the temperature of the heat treatment is 260–340°C; In step 4, the cryogenic treatment involves cooling to ≤-130℃; In step 5, the temperature of the heat treatment is 260–340°C.

2. The method according to claim 1, characterized in that, In step 1, the heating rate of the heat treatment is ≤30℃ / min, and the holding time is ≥1h.

3. The method according to claim 1, characterized in that, In step 2, the cooling rate of the cryogenic treatment is ≤10℃ / min, and the holding time is ≥24h.

4. The method according to claim 1, characterized in that, In step 3, the heating rate of the heat treatment is ≤30℃ / min, and the holding time is ≥1h.

5. The method according to claim 1, characterized in that, In step 4, the cooling rate of the cryogenic treatment is ≤10℃ / min, and the holding time is ≥24h.

6. The method according to claim 1, characterized in that, In step 5, the heating rate of the heat treatment is ≤30℃ / min, and the holding time is ≥1h.

7. The method according to claim 1, characterized in that, In step 1, the heat treatment process includes: heating from room temperature to 260-360°C at a heating rate of 20±10°C / min, holding at that temperature for 1-10 hours, and then air cooling to room temperature.

8. The method according to claim 1, characterized in that, In step 2, the cryogenic treatment process includes: cooling to -130 to -180°C at a cooling rate of 5 to 10°C / min, holding at that temperature for 24 to 48 hours, and then heating back to room temperature.

9. The method according to claim 1, characterized in that, In step 3, the heat treatment process includes: heating from room temperature to 260-340°C at a heating rate of 20±10°C / min, holding at that temperature for 1-6 hours, and then air cooling to room temperature.

10. The method according to claim 1, characterized in that, In step 4, the cryogenic treatment process includes: cooling to -130 to -180°C at a cooling rate of 5 to 10°C / min, holding at that temperature for 24 to 48 hours, and then heating back to room temperature; In step 5, the heat treatment process includes: heating from room temperature to 260-340°C at a heating rate of 20±10°C / min, holding at that temperature for 1-6 hours, and then air cooling to room temperature.

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