High-toughness rare earth magnesium alloy component and electric arc additive manufacturing method

Abstract

According to the high-strength and high-toughness rare earth magnesium alloy component and the electric arc additive manufacturing method, on the basis that existing alloy components are kept, the residual stress of the formed component is released to the maximum extent by regulating and controlling the electric arc additive forming process and the subsequent annealing process, and meanwhile recrystallization distortion stored energy is kept. On the basis, special solid solution aging treatment is accurately matched, original matrix grains are refined through recrystallization, a special structure with the microstructure being grains with the diameter being 12-20 microns and having no long-period stacking structure (LPSO phase) on the grain boundary is obtained, and electric arc additive manufacturing of the high-strength, high-toughness, plasticity-free and anisotropic rare earth magnesium alloy component is achieved. The problem of electric arc additive manufacturing of the large-size rare earth magnesium alloy component is solved.

Description

Technical Field

[0001] The present application belongs to the field of additive manufacturing of metal materials, and specifically relates to a high-strength and toughness rare earth magnesium alloy component and an arc additive manufacturing method. Background Art

[0002] Rare earth magnesium alloys have the characteristics of low density, high specific strength, good damping and excellent processability, and are widely used in aerospace, rail transportation and other fields. Compared with traditional magnesium alloys, rare earth magnesium alloys have good room temperature and high temperature tensile properties, fatigue resistance and creep resistance, and are more suitable for high-performance manufacturing of aerospace components. In rare earth magnesium alloys represented by Mg-Gd-Y series, Gd and Y can play a good role in solid solution strengthening and second phase strengthening. In the subsequent solid solution aging process, fine precipitation phases can be precipitated, which effectively hinders dislocation slip and improves the mechanical properties of the alloy. At present, in actual engineering applications, large rare earth magnesium alloy components are mainly manufactured by integral casting + CNC machining composite manufacturing process, which has serious limitations in manufacturing, mainly including: (1) There are serious defects such as macroscopic composition segregation and pores in the casting of large and complex components, resulting in inconsistent mechanical properties of various parts of the component, and difficult to control the quality of component forming; (2) During the casting process of large and complex components, it is very easy to cause deformation and cracking of the component due to the large amount of melt solidification shrinkage, and the component yield is low. Therefore, the preparation of rare earth magnesium alloy components with high quality consistency and yield is a prerequisite for its application.

[0003] As an emerging digital manufacturing technology, arc additive manufacturing technology is based on the three-dimensional model of the component. It uses an arc to melt the metal wire and deposit it layer by layer along the planned path to prepare large, complex, high-performance blank components. With a small amount of machining, high-performance components that meet engineering needs can be prepared. However, rare earth magnesium alloys have high thermal conductivity and fast heat dissipation, which leads to a small molten pool range and unstable droplet transition in arc additive forming, resulting in weak interlayer bonding and easy formation of defects, which reduces the mechanical properties of rare earth magnesium alloy components. According to literature search, patent CN 116618792A discloses an arc additive manufacturing method for Mg-Y-Nd-Zr rare earth magnesium alloy structural parts. The components are subjected to arc additive forming, heat preservation treatment and subsequent heat treatment to obtain components with better mechanical properties. However, the solid solution strengthening and precipitation strengthening capabilities of Mg-Gd rare earth magnesium alloy components are significantly higher than those of Mg-Y-Nd-Zr rare earth magnesium alloys. The above method is difficult to apply to arc additive forming of Mg-Gd rare earth magnesium alloy components. Patent CN117182251A discloses a forming method of Mg-9.2Gd-3.2Y-2Zn-0.4Zr alloy. The invention uses a liquid nitrogen spray gun to spray liquid nitrogen during forming to accelerate the cooling of the formed component to obtain a fine-grained component and improve the mechanical properties of the component. However, this method makes the arc additive forming operation process complicated, and it is difficult to accurately control the cooling rate of the component, which reduces the manufacturing efficiency of the arc additive forming. Patent CN117283088A discloses an arc forming process of Mg-9.2Gd-3.2Y-2Zn-0.4Zr alloy. The invention adjusts the process parameters to make the heat accumulation of the formed component below 246°C, and produces a large amount of network second phase Mg5 (Gd, Y) at the grain boundary to improve the hardness and compression performance of the component. However, the forming process parameters of the invention are relatively narrow and difficult to apply to industrial production. In view of the high-quality and high-performance manufacturing requirements of aerospace rare earth magnesium alloy components, it is urgent to carry out research on arc additive forming methods for high-performance and high-efficiency rare earth magnesium alloy components to meet their engineering application requirements. Summary of the invention

[0004] The technical problem solved by the present application is: to overcome the shortcomings of the prior art and provide an arc additive manufacturing method for high-strength and toughness rare earth magnesium alloy components. By regulating the arc additive forming process and accurately matching the subsequent heat treatment method, the structure and mechanical properties of the formed components are made consistent, the overall mechanical properties of the components are improved, and the manufacturing efficiency is improved.

[0005] A method for arc additive forming of a high-strength and tough rare earth magnesium alloy component comprises the following steps:

[0006] S1: Loading rare earth magnesium alloy wire into the wire feeder;

[0007] S2: After cleaning the magnesium alloy substrate, fix it on the working platform and start the dehumidification equipment to perform dehumidification work;

[0008] S3: Import the component 3D CAD model into the arc additive forming software for layered slicing and formulating the forming path;

[0009] S4: When the humidity in the forming chamber is lower than 50%, the arc is started to melt the wire and deposit it into a dense component. After one layer is deposited, the next layer is deposited after a set time interval.

[0010] S5: repeating steps S4 and S5 to continuously deposit and manufacture a rare earth magnesium alloy component;

[0011] S6: After the deposition is completed, the rare earth magnesium alloy component and the substrate are placed in a heat treatment furnace for annealing;

[0012] S7: separating the annealed rare earth magnesium alloy component from the substrate, and cutting the rare earth magnesium alloy component from the substrate;

[0013] S8: placing the rare earth magnesium alloy component into a heat treatment furnace for solid solution aging special heat treatment to obtain a final rare earth magnesium alloy component.

[0014] In step S4, the arc additive forming deposition process parameters are: welding wire dry wire extension 10-14 mm, argon gas flow rate 25-35 L / min, current 100-120 A, wire feeding rate 9-10 m / min, deposition rate 6-8 mm / s, layer thickness 3-4 mm, and overlap rate 55-60%.

[0015] In step S4, by controlling the arc additive forming process parameters, the energy density of the rare earth magnesium alloy deposition area is controlled to be 45-55 J / mm, the overlap rate is 55-60%, and the cooling rate at the front of the forming molten pool interface is 102-102.5 K / s, and grains with a diameter of 25-35 μm and LPSO aggregated phases with a diameter of 0.1-0.2 μm at the grain boundaries are prepared, providing a driving force for the subsequent recrystallization of the matrix grains.

[0016] In step S4, the interval time between layers is 15 to 25 minutes;

[0017] In step S4, the diameter of the rare earth magnesium alloy wire is Φ1.2 mm;

[0018] In step S4, the rare earth magnesium alloy wire has the following components, by mass percentage: gadolinium Gd: 8.0-12.0%, yttrium Y: 2.5-4.5%, zinc Zn: 1.5-2.5%, zirconium Zr: 0.8-1.2%, other single impurity elements: ≤0.1%, other impurity elements total ≤0.2%, and the remainder is Mg;

[0019] In step S6, the interval between the completion of the rare earth magnesium alloy component forming and the heating in the annealing furnace is no more than 4 hours;

[0020] In the step S6, the rare earth magnesium alloy component and the substrate are heated to 300-350° C. at 100-120° C. / h and kept at this temperature for 6-12 hours to eliminate the residual stress of the formed component;

[0021] In the step S8, the special heat treatment includes solution treatment and aging treatment; the solution treatment includes: heating the sample to 525-535°C at 2-5°C / min, keeping the temperature for 2-6h, and cooling to room temperature at a cooling rate of not less than 10°C / s; after the solution treatment, aging treatment is performed; the aging treatment includes: heating the sample to 200-250°C at 2-5°C / min, keeping the temperature for 250-300h, and cooling to room temperature at a cooling rate of not less than 15°C / s; through the special heat treatment, the matrix grains can be refined by recrystallization, while avoiding the growth of the original matrix grains and the aggregation of LPSO phases at the grain boundaries to reduce the grain boundary toughness, and obtaining a microstructure with grains with a diameter of 12-20μm and no LPSO phase at the grain boundaries.

[0022] The present invention proposes an arc additive manufacturing method for high-strength and toughness rare earth magnesium alloy components. The main idea is to obtain grains with a diameter of 25 to 35 μm and LPSO aggregated phases with a diameter of 0.1 to 0.2 μm at the grain boundaries by regulating the arc additive manufacturing solidification process, thereby providing a driving force for subsequent organizational performance regulation; on this basis, a special annealing treatment is precisely matched to prevent the formed component from participating in stress and causing the component to crack, while not reducing the distortion energy stored in the subsequent organizational regulation of the component; at the same time, a special solid solution aging treatment is precisely matched to obtain a microstructure with grains with a diameter of 12 to 20 μm and a special structure with no LPSO phase at the grain boundaries, thereby realizing arc additive manufacturing of high-strength and toughness rare earth magnesium alloy components.

[0023] Compared with the prior art, this application has the following beneficial technical effects:

[0024] (1) The present invention uses rare earth magnesium alloy wire as raw material and adopts arc additive forming technology to directly prepare large-sized high-performance components that meet engineering applications. Compared with the existing traditional manufacturing technology of rare earth magnesium alloy, this technology has a short manufacturing cycle, low manufacturing cost, and greatly improved material utilization.

[0025] (2) Through the "arc additive forming process control + special annealing treatment control + precise matching solution treatment control" provided by the present invention, a special microstructure with grains of 12 to 20 μm in diameter and no LPSO phase at the grain boundary is obtained, realizing arc additive manufacturing of high-strength and toughness rare earth magnesium alloy components ( Figure 1 and Table 1).

[0026] (3) The present invention achieves the preparation of high-strength and high-toughness rare earth magnesium alloy components by adjusting "arc additive forming parameters + special annealing parameters + precise matching of solid solution aging treatment parameters" without changing the composition of the existing rare earth magnesium alloy wire, and is also applicable to the design and use of other rare earth magnesium alloy components ( Figure 2 and Table 1).

[0027] (4) The "arc additive forming process control + special annealing treatment control + precise matching solution treatment control" method provided by the present invention is suitable for arc additive manufacturing of large-sized rare earth magnesium alloy components containing LPSO phase with a width ≥1000mm. The components have uniform stress release and uniform microstructure and performance, and are suitable for high-performance integrated manufacturing of large-sized complex rare earth magnesium alloy components under industrial conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is the structure of the deposited sample of the rare earth magnesium alloy obtained in comparative example 1 by arc additive manufacturing, wherein, in Figure a, it can be seen that the deposited sample presents coarse equiaxed grains, and Figure b is an enlarged view of Figure a, in which the LPSO phase in the grain can be seen;

[0029] Figure 2 This is the microstructure of the magnesium alloy arc additive manufacturing sample after special solid solution aging in Example 1. In Figure a, it can be seen that the special solid solution aging sample presents fine equiaxed grains, and Figure b is an enlarged view of Figure a, from which it can be seen that there is no LPSO phase in the grain. DETAILED DESCRIPTION

[0030] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments disclosed in the present invention will be further described in detail below with reference to the accompanying drawings.

[0031] A high-strength and tough rare earth magnesium alloy arc additive manufacturing method specifically comprises the following steps:

[0032] S1: Loading rare earth magnesium alloy wire into the wire feeder;

[0033] S2: After cleaning the magnesium alloy substrate, fix it on the working platform and start the dehumidification equipment to perform dehumidification work;

[0034] S3: Import the component 3D CAD model into the arc additive forming software for layered slicing and formulating the forming path;

[0035] S4: When the humidity in the forming chamber is lower than 50%, the arc is started to melt the wire and deposit it to form a dense component. After one layer is deposited, the next layer is deposited after a set time interval. The arc additive forming deposition process parameters are: wire elongation 10-14mm, argon gas flow 25-35L / min, current 100-120A, wire feeding rate 9-10m / min, deposition rate 6-8mm / s, layer thickness 3-4mm, overlap rate 55-60%; by controlling the arc additive forming process parameters, the energy density of the rare earth magnesium alloy deposition area is controlled to be 45-55J / mm, and the cooling rate at the front of the forming molten pool interface is 10 2 ~10 2.5 K / s, grains with a diameter of 25-35 μm and LPSO aggregated phases with a diameter of 0.1-0.2 μm at the grain boundaries were prepared, providing a driving force for the subsequent recrystallization of the matrix grains.

[0036] S5: repeating steps S4 and S5 to continuously deposit and manufacture a rare earth magnesium alloy component;

[0037] S6: After the deposition is completed, the rare earth magnesium alloy component and the substrate are placed in a heat treatment furnace for annealing; the interval between the completion of the rare earth magnesium alloy component forming and the heating in the annealing furnace shall not exceed 4 hours; the rare earth magnesium alloy component and the substrate are heated to 300-350°C at a rate of 100-120°C / h and kept at this temperature for 6-12 hours;

[0038] S7: separating the annealed rare earth magnesium alloy component from the substrate, and cutting the rare earth magnesium alloy component from the substrate;

[0039] S8: placing the rare earth magnesium alloy component into a heat treatment furnace for a special heat treatment of solution and aging to obtain a final rare earth magnesium alloy component; the special heat treatment includes solution treatment and aging treatment; the solution treatment includes: heating the sample to 525-535°C at 2-5°C / min, keeping it warm for 2-6h, and cooling it to room temperature at a cooling rate of not less than 10°C / s; after the solution treatment is completed, aging treatment is performed; the aging treatment includes: heating the sample to 200-250°C at 2-5°C / min, keeping it warm for 250-300h, and cooling it to room temperature at a cooling rate of not less than 15°C / s.

[0040] The rare earth magnesium alloy wire used in the following examples and comparative examples has the following composition, calculated by mass: gadolinium Gd: 12.0%, yttrium Y: 3.5%, zinc Zn: 2.0%, zirconium Zr: 1.02%, other single impurity elements: ≤0.1%, other impurity elements total ≤0.2%, and the balance is Mg.

[0041] Example 1

[0042] A method for arc additive manufacturing of a high-strength and tough rare earth magnesium alloy component, specifically comprising:

[0043] S1: Loading rare earth magnesium alloy wire into the wire feeder;

[0044] S2: After cleaning the magnesium alloy substrate, fix it on the working platform and start the dehumidification equipment to perform dehumidification work;

[0045] S3: Import the component 3D CAD model into the arc additive forming software for layered slicing and formulating the forming path;

[0046] S4: When the humidity in the forming chamber is lower than 50%, the arc is started to melt the wire and deposit it to form a dense component. After one layer is deposited, the next layer is deposited after a set time interval. The arc additive forming deposition process parameters are: wire elongation 10mm, argon gas flow 25L / min, current 100A, wire feeding rate 9m / min, deposition rate 6mm / s, layer thickness 3mm, overlap rate 55%. By controlling the arc additive forming process parameters, the energy density of the rare earth magnesium alloy deposition area is controlled to be 45J / mm, and the cooling rate of the front edge of the forming molten pool interface is 10 2 K / s, a rare earth magnesium alloy layer with grains with a diameter of 25 μm and LPSO aggregated phase with a diameter of 0.1 μm at the grain boundary was prepared, which provided a driving force for the subsequent recrystallization of the matrix grains.

[0047] S5: repeating steps S4 and S5 to continuously deposit and manufacture a rare earth magnesium alloy component;

[0048] S6: After the deposition is completed, the rare earth magnesium alloy component and the substrate are placed in a heat treatment furnace for annealing; the heating interval from the completion of the rare earth magnesium alloy component forming to the heating in the annealing furnace is 2 hours; the rare earth magnesium alloy component and the substrate are heated to 300°C at 120°C / h and kept at this temperature for 6 hours;

[0049] S7: separating the annealed rare earth magnesium alloy component from the substrate, and cutting the rare earth magnesium alloy component from the substrate;

[0050] S8: placing the rare earth magnesium alloy component into a heat treatment furnace for a special heat treatment of solution and aging to obtain the final rare earth magnesium alloy component; the special heat treatment includes solution treatment and aging treatment; the solution treatment includes: heating the sample to 525°C at 2°C / min, keeping it warm for 12 to 16 hours, and cooling it to room temperature at a controlled cooling rate of 12°C / s; after the solution treatment is completed, aging treatment is performed; the aging treatment includes: heating the sample to 200°C at 2°C / min, keeping it warm for 250 hours, and cooling it to room temperature at a controlled cooling rate of 16°C / s.

[0051] Example 2

[0052] S1: Loading rare earth magnesium alloy wire into the wire feeder;

[0053] S2: After cleaning the magnesium alloy substrate, fix it on the working platform and start the dehumidification equipment to perform dehumidification work;

[0054] S3: Import the component 3D CAD model into the arc additive forming software for layered slicing and formulating the forming path;

[0055] S4: When the humidity in the forming chamber is lower than 50%, the arc is started to melt the wire and deposit it to form a dense component. After one layer is deposited, the next layer is deposited after a set time interval. The arc additive forming deposition process parameters are: wire elongation 12mm, argon gas flow 30L / min, current 110A, wire feeding rate 9.5m / min, deposition rate 7mm / s, layer thickness 3.5mm, overlap rate 56%; By controlling the arc additive forming process parameters, the energy density of the rare earth magnesium alloy deposition area is controlled to be 55J / mm, and the cooling rate of the front edge of the forming molten pool interface is 10 2.2 K / s, grains with a height of 3.5 mm and a diameter of 29 μm were prepared, and the grain boundaries contained LPSO aggregated phases with a diameter of 0.15 μm, which provided driving force for the subsequent recrystallization of matrix grains.

[0056] S5: repeating steps S4 and S5 to continuously deposit and manufacture a rare earth magnesium alloy component;

[0057] S6: After the deposition is completed, the rare earth magnesium alloy component and the substrate are placed in a heat treatment furnace for annealing; the heating interval from the completion of the rare earth magnesium alloy component to the annealing furnace is 3 hours; the rare earth magnesium alloy component and the substrate are heated to 320°C at 120°C / h and kept warm for 11 hours;

[0058] S7: separating the annealed rare earth magnesium alloy component from the substrate, and cutting the rare earth magnesium alloy component from the substrate;

[0059] S8: placing the rare earth magnesium alloy component into a heat treatment furnace for a special heat treatment of solution and aging to obtain the final rare earth magnesium alloy component; the special heat treatment includes solution treatment and aging treatment; the solution treatment includes: heating the sample to 530°C at 3°C / min, keeping it warm for 14 hours, and cooling it to room temperature at a controlled cooling rate of 14°C / s; after the solution treatment is completed, aging treatment is performed; the aging treatment includes: heating the sample to 220°C at 4°C / min, keeping it warm for 280 hours, and cooling it to room temperature at a controlled cooling rate of 17°C / s.

[0060] Example 3

[0061] S1: Loading rare earth magnesium alloy wire into the wire feeder;

[0062] S2: After cleaning the magnesium alloy substrate, fix it on the working platform and start the dehumidification equipment to perform dehumidification work;

[0063] S3: Import the component 3D CAD model into the arc additive forming software for layered slicing and formulating the forming path;

[0064] S4: When the humidity in the forming chamber is lower than 50%, the arc is started to melt the wire and deposit it to form a dense component. After one layer is deposited, the next layer is deposited after a set time interval. The arc additive forming deposition process parameters are: wire elongation 14mm, argon gas flow 35L / min, current 120A, wire feeding rate 9-10m / min, deposition rate 8mm / s, layer thickness 4mm, overlap rate 60%; By controlling the arc additive forming process parameters, the energy density of the rare earth magnesium alloy deposition area is controlled to be 50J / mm, and the cooling rate of the front edge of the forming molten pool interface is 10 2.5 K / s, grains with a height of 4 mm and a diameter of 35 μm and LPSO aggregated phase with a diameter of 0.2 μm at the grain boundary were prepared, providing a driving force for the subsequent recrystallization of the matrix grains.

[0065] S5: repeating steps S4 and S5 to continuously deposit and manufacture a rare earth magnesium alloy component;

[0066] S6: After the deposition is completed, the rare earth magnesium alloy component and the substrate are placed in a heat treatment furnace for annealing; the interval time from the completion of the rare earth magnesium alloy component forming to the heating of the annealing furnace is 4 hours; the rare earth magnesium alloy component and the substrate are heated to 350°C at 120°C / h and kept at this temperature for 12 hours;

[0067] S7: separating the annealed rare earth magnesium alloy component from the substrate, and cutting the rare earth magnesium alloy component from the substrate;

[0068] S8: placing the rare earth magnesium alloy component into a heat treatment furnace for a special heat treatment of solution and aging to obtain the final rare earth magnesium alloy component; the special heat treatment includes solution treatment and aging treatment; the solution treatment includes: heating the sample to 535°C at 5°C / min, keeping it warm for 16 hours, and cooling it to room temperature at a controlled cooling rate of 15°C / s; after the solution treatment is completed, aging treatment is performed; the aging treatment includes: heating the sample to 250°C at 5°C / min, keeping it warm for 300 hours, and cooling it to room temperature at a controlled cooling rate of 18°C / s.

[0069] Example 4

[0070] The only difference from Example 1 is that the arc additive forming deposition process parameters are: wire dry wire extension 11mm, argon gas flow rate 28L / min, current 108A, wire feeding rate 9.2m / min, deposition rate 7.0mm / s, layer thickness 3.4mm, overlap rate 59%; by controlling the arc additive forming process parameters, the energy density of the rare earth magnesium alloy deposition area is controlled to be 49J / mm, and the cooling rate of the front edge of the forming molten pool interface is 10 2.2K / s, a rare earth magnesium alloy layer with grains with a diameter of 28.5 μm and LPSO aggregated phase with a diameter of 0.16 μm at the grain boundary was prepared, which provided a driving force for the subsequent recrystallization of the matrix grains.

[0071] Example 5

[0072] The only difference from Example 1 is that the arc additive forming deposition process parameters are: wire dry wire extension 13.5mm, argon gas flow rate 32L / min, current 118A, wire feeding rate 9.8m / min, deposition rate 7.8mm / s, layer thickness 3.8mm, overlap rate 57%; by controlling the arc additive forming process parameters, the energy density of the rare earth magnesium alloy deposition area is controlled to be 52J / mm, and the cooling rate of the front edge of the forming molten pool interface is 10 2.3 K / s, a rare earth magnesium alloy layer with grains with a diameter of 32 μm and LPSO aggregated phase with a diameter of 0.18 μm at the grain boundary was prepared, which provided a driving force for the subsequent recrystallization of the matrix grains.

[0073] Comparative Example 1

[0074] The difference between this comparative example and Example 1 is that the comparative example 1 is prepared using the forming parameters of Example 1, only annealing treatment is performed, and subsequent solution aging treatment is not performed. (That is, S1-S7 are the same as Example 1, and S8 is not performed.)

[0075] Comparative Example 2

[0076] The difference between this comparative example and Example 1 is that the comparative example 1 is prepared using the forming parameters of Example 1, without annealing treatment, and with subsequent solution aging treatment (i.e., without S6 and S7). This method easily leads to cracking of the sample, and it is difficult to obtain a complete sample.

[0077] Figure 1 The microstructure of the deposited sample was obtained for Comparative Example 1. Figure 2 The rare earth magnesium alloy structure is obtained for Example 1. The tensile strength Rm, yield strength Rp0.2 and elongation (A%) of the rare earth magnesium alloys of the comparative example and the example are tested, and the test results are shown in Table 1.

[0078] like Figure 1 As shown in Table 1, Comparative Example 1 presents coarse grains, LPSO phase agglomerates on the grain boundaries, the tensile strength and yield strength of the sample are significantly lower than the application requirements, and the samples in two directions have plastic anisotropy. After adopting the present invention, the tensile strength and elongation of the sample are significantly improved, and the samples in two directions have no plastic anisotropy, which is close to the application requirements. By adopting the method of the present invention, high-strength and tough rare earth magnesium alloy arc additive manufacturing components can be directly prepared without changing the existing rare earth magnesium alloy composition.

[0079] Table 1 Comparison of strength and toughness of rare earth magnesium alloy components manufactured by arc additive manufacturing, annealing and special solution treatment

[0080]

[0081] In step S4, when the arc current is too low (less than 100A), the wire feeding rate is too low (less than 9m / min) and the deposition rate is too low (less than 6mm / s), the heat accumulation in the arc additive forming process is too high, and coarse grains are easily formed, resulting in cracking of rare earth magnesium alloy components, which cannot be used in industrial production; when the arc current is too high (greater than 120A), the wire feeding rate is too high (greater than 10m / min) and the deposition rate is too high (greater than 8mm / s), coarse grains and precipitation phase structures are formed, and the grain boundary distortion energy is low, which cannot provide sufficient driving force for the subsequent special solid solution aging treatment, and the fine grains and fine precipitation phase structures at the grain boundaries required for high-strength and tough rare earth magnesium alloys cannot be obtained.

[0082] In step S6, when the interval from the completion of the rare earth magnesium alloy component forming to the heating of the annealing furnace is too long (greater than 4h), the residual stress in the component cannot be released in time, which can easily lead to the cracking of the component and cannot be applied to industrial production; when the heating rate of the rare earth magnesium alloy is too low (less than 100℃ / h), the residual stress of the component cannot be released in time, which can easily lead to the cracking of the component; when the heating rate of the rare earth magnesium alloy component is too high (greater than 120℃ / h), the residual stress of the component is released too quickly, which can easily lead to the cracking of the component; when the insulation temperature of the rare earth magnesium alloy component is too low (less than 300℃ / h), the residual stress of the component is not released in time, which can easily lead to the cracking of the component. ℃), the holding time is too short (less than 6h), and the residual stress of the component cannot be effectively removed; when the holding temperature of the rare earth magnesium alloy component is too high (higher than 350℃), the holding time is too long (higher than 12h), it is easy to cause the component to soften and reduce the subsequent recrystallization driving force of the component; the recrystallization driving force of the sample is too small, and recrystallization and grain refinement cannot occur; when the holding temperature of the rare earth magnesium alloy component is too high (higher than 350℃), the holding time is too long (higher than 12h), the recrystallized grains of the sample grow secondary, the grains are too coarse, and the mechanical properties of the sample cannot be improved.

[0083] In step S8, when the solution temperature is too low (less than 525°C), the holding time is too short (less than 2h), the recrystallization drive is too small, and recrystallization and grain refinement cannot occur, and the tensile properties of the sample are lower than the use requirements; when the solution temperature is too high (greater than 535°C), the holding time is too long (greater than 6h), the fine grains and fine precipitation phases at the grain boundaries of the sample are transformed into coarse grains and coarse precipitation phases, and the tensile properties of the sample are lower than the standard requirements; when the aging temperature is too low (less than 200°C), the holding time is too short (less than 250h), the sample cannot obtain fine grains and fine precipitation phases at the grain boundaries, and the tensile properties of the sample are lower than the standard requirements; when the aging temperature is too high (greater than 300°C), the holding time is too long (greater than 300h), the sample is transformed into coarse grains and coarse grain boundary precipitation phase structure, and the tensile properties of the sample are lower than the standard requirements.

[0084] The contents not described in detail in this application specification belong to the common knowledge of those skilled in the art.

[0085] The present application is described in detail above in conjunction with specific implementation methods and exemplary examples, but these descriptions cannot be understood as limiting the present application. Those skilled in the art understand that, without departing from the spirit and scope of the present application, a variety of equivalent replacements, modifications or improvements can be made to the technical solution of the present application and its implementation methods, all of which fall within the scope of the present application. The scope of protection of the present application shall be subject to the attached claims.

Claims

1. A method for arc additive manufacturing of high-strength and toughness rare earth magnesium alloy components, characterized in that: include: S1. Fix the substrate on the working platform in the forming chamber; S2. Dehumidify the forming chamber until the humidity in the forming chamber is lower than 50%; S3, depositing a layer of rare earth magnesium alloy wire according to the process parameters of arc additive forming deposition and the forming path; the process parameters of arc additive forming deposition are: wire elongation 10-14 mm, argon gas flow 25-35 L / min, current 100-120 A, wire feeding rate 9-10 m / min, deposition rate 6-8 mm / s, layer thickness 3-4 mm, overlap rate 55-60%; S4, set the interval time and proceed to deposit the next layer; S5, repeating steps S3 and S4, continuously depositing to produce a rare earth magnesium alloy component; S6, placing the rare earth magnesium alloy component and the substrate into a heat treatment furnace for annealing; S7, separating the annealed rare earth magnesium alloy component from the substrate, and cutting the rare earth magnesium alloy component from the substrate; S8: placing the rare earth magnesium alloy component into a heat treatment furnace for special heat treatment to obtain a final rare earth magnesium alloy component.

2. The arc additive manufacturing method for a high-strength and tough rare earth magnesium alloy component according to claim 1, characterized in that: In S4, the time is set to 15 to 25 minutes.

3. The arc additive manufacturing method for a high-strength and tough rare earth magnesium alloy component according to claim 1, characterized in that: Taking the sum of the mass percentages of the various components as 100%, the rare earth magnesium alloy wire comprises: gadolinium Gd: 8.0-12.0%, yttrium Y: 2.5-4.5%, zinc Zn: 1.5-2.5%, zirconium Zr: 0.8-1.2%, and the remaining impurity elements total ≤0.2%, and the remaining impurity elements include each single impurity element: ≤0.1%, and the remainder is Mg.

4. The arc additive manufacturing method for a high-strength and tough rare earth magnesium alloy component according to claim 1, characterized in that: The rare earth magnesium alloy component manufactured by continuous deposition has grains with a diameter of 25 to 35 μm and grain boundaries containing LPSO aggregate phases with a diameter of 0.1 to 0.2 μm.

5. The arc additive manufacturing method for a high-strength and tough rare earth magnesium alloy component according to claim 1, characterized in that: In S6, the interval between the completion of forming of the rare earth magnesium alloy component and the placement of the rare earth magnesium alloy component into the internal heat treatment furnace and the start of heating and temperature rise is no more than 4 hours.

6. The arc additive manufacturing method for a high-strength and tough rare earth magnesium alloy component according to claim 1, characterized in that: In the above S6, the annealing treatment includes: heating to 300-350° C. at 100-120° C. / h and keeping the temperature for 6-12 hours.

7. The arc additive manufacturing method for a high-strength and tough rare earth magnesium alloy component according to claim 1, characterized in that: In S8, the special heat treatment includes solution treatment and aging treatment performed sequentially.

8. The arc additive manufacturing method for a high-strength and tough rare earth magnesium alloy component according to claim 7, characterized in that: The solution treatment comprises: heating the rare earth magnesium alloy component to 525-535° C. at a rate of 2-5° C. / min, keeping the temperature for 2-6 hours, and cooling to room temperature at a cooling rate of no less than 10° C. / s.

9. The arc additive manufacturing method for a high-strength and tough rare earth magnesium alloy component according to claim 7, characterized in that: The aging treatment comprises: heating the sample to 200-250° C. at 2-5° C. / min, keeping the temperature for 250-300 hours, and cooling to room temperature at a cooling rate of no less than 15° C. / s.

10. A high-strength and tough rare earth magnesium alloy component, characterized in that: The high-strength and toughness rare earth magnesium alloy component is prepared by the arc additive manufacturing method according to any one of claims 1-9.

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