A high-performance heterogeneous magnesium alloy and additive manufacturing method thereof

Abstract

The present invention belongs to the field of additive manufacturing and provides a high-performance heterogeneous magnesium alloy and an additive manufacturing method thereof, which comprises: on a magnesium alloy substrate, using two magnesium alloy welding wires to perform alternating zigzag and straight line additive manufacturing; when one of the magnesium alloy welding wires is added, the welding gun moves in a cyclic zigzag oscillating manner, with an oscillation radius of 2-11 mm, a spacing of 2-8 mm between the centers of any two adjacent zigzag lines, a welding gun travel speed of 3-15 mm / s, a welding current of 90-150 A, a welding voltage of 12-26 V, and a wire feed speed of 4-20 m / min n, after adding 1-10 layers, cooled to 50-120°C; when adding another magnesium alloy welding wire, the welding gun moves in a straight line, with a welding gun travel speed of 4-16 mm / s, welding current of 75-150A, welding voltage of 13-27V, and wire feed speed of 5-22 m / min. After adding 1-10 layers, it is cooled to 55-125°C and polished to remove impurities. After that, the two magnesium alloy welding wires are alternately added on the magnesium alloy substrate for additive manufacturing. This cycle is repeated to finally obtain 30-80 layers of high-performance heterogeneous magnesium alloy.

Description

Technical Field

[0001] The present invention belongs to the field of additive manufacturing, and specifically relates to a high-performance heterogeneous magnesium alloy and an additive manufacturing method thereof. Background Art

[0002] As the lightest structural alloy, magnesium alloy boasts advantages such as high specific strength, good damping properties, and excellent electromagnetic shielding performance in addition to its low density. It is widely used in aviation, aerospace, and transportation. Currently, the more complex the shape of a product part, the higher the forming requirements. Traditional casting processes struggle to directly form complex components, and the need for molds complicates the manufacturing process, leading to long development cycles. Therefore, a new alternative forming process is needed.

[0003] Additive manufacturing (AM), a new rapid prototyping technology, utilizes a "bottom-up" material stacking method. This allows for efficient and rapid prototyping of complex components without the need for molds and a short development cycle, making it widely used in various metal forming applications. However, when using single-component magnesium alloy welding wire for AM, the AM material's performance is relatively limited, making it difficult to meet the needs of diverse applications. Furthermore, the mechanical properties of low-alloy alloys are relatively low. To improve the mechanical properties of these materials, AM requires the use of welding wires with high alloying or rare earth content, or welding wires with multiple components. However, these welding wires with high alloying or rare earth content increase production costs. Furthermore, due to poor compatibility and interfacial bonding between the different component materials, AM processes can lead to delamination, anisotropy, and cracking. This can lead to decreased mechanical properties, premature fracture, uneven distribution of mechanical properties, and difficulty in simultaneously improving the strength and ductility of AM materials. Furthermore, multi-component welding wires and their AM process parameters are difficult to adjust, resulting in high manufacturing costs and long production cycles. Therefore, how to reduce raw material costs, simplify processes, shorten time cycles, enhance interface bonding, and improve the strength and plasticity of additive manufacturing materials are technical challenges that need to be solved urgently. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a high-performance heterogeneous magnesium alloy, and its additive manufacturing method includes the following steps:

[0005] (1) polishing the surface of the magnesium alloy substrate with sandpaper and cleaning it with anhydrous ethanol, and then drying it with a hair dryer to remove stains and an oxide layer on the surface of the magnesium alloy substrate to obtain a magnesium alloy substrate with a clean surface;

[0006] (2) The magnesium alloy substrate obtained in step (1) is fixed on an additive manufacturing workbench, and under a protective gas, the protective gas flow rate is 10-28 L / min, and magnesium alloy welding wire 1 and magnesium alloy welding wire 2 are used to perform alternating additive manufacturing on the magnesium alloy substrate; the alternating additive manufacturing is: alternating folded line and straight line additive manufacturing; wherein the folded line additive manufacturing: the vertical distance between the welding gun and the substrate is adjusted to 10-26 mm, firstly, magnesium alloy welding wire 1 is used for additive manufacturing, and the welding gun moves in a folded line swinging manner, the swing radius is 2-11 mm, and the distance between any two adjacent folded line centers during the folded line swinging process is 2-8 mm, the travel speed of the welding gun is 3-15 mm / s, and the welding current is 9 0-150A, welding voltage is 12-26V, wire feeding speed is 4-20m / min, after additive manufacturing 1-10 layers, cooling to 50-120°C, grinding to remove impurities; the linear additive manufacturing: using magnesium alloy welding wire 2 for additive manufacturing, the welding gun moves in a straight line, the welding gun travel speed is 4-16mm / s, the welding current is 75-150A, the welding voltage is 13-27V, the wire feeding speed is 5-22m / min, after additive manufacturing 1-10 layers, cooling to 55-125°C, grinding to remove impurities, and then performing alternating additive manufacturing on the magnesium alloy substrate according to broken line additive manufacturing and linear additive manufacturing; repeating this cycle, and finally obtaining 30-80 layers of high-performance heterogeneous magnesium alloy;

[0007] The magnesium alloy in step (1) is one of AZ31 magnesium alloy, AZ51 magnesium alloy, ZK60 magnesium alloy or ZK61 magnesium alloy;

[0008] The protective gas in step (2) is high-purity argon with a purity of ≥99.99%, or a mixture of argon and helium, or a mixture of CO2 and argon; the volume ratio of argon to helium is 1.5-3:7-8.5; the volume ratio of CO2 to argon is 2-5:95-98;

[0009] The diameter of the magnesium alloy welding wire 1 is 1.1-6.0 mm;

[0010] The diameter of the magnesium alloy welding wire 2 is 1.2-5.8 mm;

[0011] The magnesium alloy welding wire 1 is one of AZ31 magnesium alloy welding wire and AZ51 magnesium alloy welding wire;

[0012] The magnesium alloy welding wire 2 is one of ZK60 magnesium alloy welding wire and ZK61 magnesium alloy welding wire.

[0013] Furthermore, the vertical distance between the welding gun and the substrate in step (2) is 11-19 mm.

[0014] Furthermore, the fold line additive manufacturing described in step (2) has the following characteristics: the swing radius is 3-10 mm, the spacing between any two adjacent fold line centers during the fold line swing is 3-7 mm, the welding gun travel speed is 4-14 mm / s, the welding current is 95-145 A, the welding voltage is 13-25 V, and the wire feeding speed is 5-19 m / min.

[0015] Furthermore, in the linear additive manufacturing described in step (2), the travel speed of the welding gun is 5-13 mm / s, the welding current is 80-140 A, the welding voltage is 14-25 V, and the wire feeding speed is 6-21 m / min.

[0016] Furthermore, step (2) ultimately yields 32-76 layers of high-performance heterogeneous magnesium alloy. DETAILED DESCRIPTION

[0017] Example 1

[0018] The preparation method of the high performance heterogeneous magnesium alloy 1 is as follows:

[0019] AZ31 magnesium alloy substrate, AZ31 and ZK60 magnesium alloy welding wires with a wire diameter of 1.2mm;

[0020] Step 1: Polish the surface of the AZ31 magnesium alloy substrate with sandpaper and clean it with anhydrous ethanol, and then use a hair dryer to dry it to remove stains and oxide layers on the surface of the AZ31 magnesium alloy substrate to obtain an AZ31 magnesium alloy substrate with a clean surface.

[0021] Step 2: The magnesium alloy substrate obtained in step (1) is fixed on an additive manufacturing workbench. Under a shielding gas, the shielding gas is argon with a purity of 99.9% and the shielding gas flow rate is 16L / min. AZ31 and ZK60 magnesium alloy welding wires are used to perform alternating additive manufacturing on the magnesium alloy substrate. The alternating additive manufacturing is alternating between zigzag and straight line additive manufacturing. In the zigzag additive manufacturing, the vertical distance between the welding gun and the substrate is adjusted to 12mm. First, AZ31 magnesium alloy welding wire is used for additive manufacturing. The welding gun moves in a cyclic zigzag swing mode with a swing radius of 6mm. During the zigzag swing process, the spacing between any two adjacent zigzag lines is 4mm. The welding gun travels at a speed of 7mm / s, the welding current is 110A, the welding voltage is 14V, and the wire feeding speed is 7m / min. After adding one layer, cool it to 50°C and grind to remove impurities; the linear additive manufacturing: use ZK60 magnesium alloy welding wire for additive manufacturing, the welding gun moves in a straight line, the welding gun travels at a speed of 6mm / s, the welding current is 100A, the welding voltage is 14V, and the wire feeding speed is 6.2m / min. After completing one layer of additive manufacturing, cool it to 55°C, grind to remove impurities, and then perform alternating additive manufacturing on the magnesium alloy substrate according to the above-mentioned two magnesium alloy welding wires. Repeat this cycle to finally obtain 38 layers of high-performance heterogeneous magnesium alloy 1.

[0022] Example 2

[0023] The preparation method of high performance heterogeneous magnesium alloy 2 is as follows:

[0024] AZ31 magnesium alloy substrate, AZ31 and ZK60 magnesium alloy welding wire with a wire diameter of 1.4mm;

[0025] Step 1: Polish the surface of the AZ31 magnesium alloy substrate with sandpaper and clean it with anhydrous ethanol, and then use a hair dryer to dry it to remove stains and oxide layers on the surface of the AZ31 magnesium alloy substrate to obtain an AZ31 magnesium alloy substrate with a clean surface.

[0026] Step 2: The magnesium alloy substrate obtained in step (1) is fixed on an additive manufacturing workbench. Under a shielding gas, the shielding gas is argon with a purity of 99.9% and the shielding gas flow rate is 18L / min. AZ31 and ZK60 magnesium alloy welding wires are used to perform alternating additive manufacturing on the magnesium alloy substrate. The alternating additive manufacturing is alternating between zigzag and straight line additive manufacturing. In the zigzag additive manufacturing, the vertical distance between the welding gun and the substrate is adjusted to 14mm. First, AZ31 magnesium alloy welding wire is used for additive manufacturing. The welding gun moves in a cyclic zigzag swing mode with a swing radius of 7mm. During the zigzag swing process, the spacing between any two adjacent zigzag lines is 5mm. The welding gun travels at a speed of 6.6mm / s, a welding current of 100A, a welding voltage of 13.6V, and a wire feed speed of 6.6m / min. After adding two layers, the material is cooled to 70°C and polished to remove impurities. For linear additive manufacturing, ZK60 magnesium alloy welding wire is used for additive manufacturing. The welding gun moves in a straight line at a speed of 8.5 mm / s, a welding current of 120A, a welding voltage of 14.6V, and a wire feed speed of 7 m / min. After adding two layers, the material is cooled to 80°C and polished to remove impurities. Then, additive manufacturing is performed alternately using the two magnesium alloy welding wires on the magnesium alloy substrate. This cycle is repeated, ultimately producing 40 layers of high-performance heterogeneous magnesium alloy 2.

[0027] Comparative Example 1

[0028] The preparation method of additively manufactured magnesium alloy 3 is as follows:

[0029] AZ31 magnesium alloy substrate and AZ31 magnesium alloy welding wire with a wire diameter of 1.2mm are used;

[0030] Step 1: Polish the surface of the AZ31 magnesium alloy substrate with sandpaper and clean it with anhydrous ethanol, and then use a hair dryer to dry it to remove stains and oxide layers on the surface of the AZ31 magnesium alloy substrate to obtain an AZ31 magnesium alloy substrate with a clean surface.

[0031] Step 2: The magnesium alloy substrate obtained in step (1) is fixed on an additive manufacturing workbench. Under argon protection with an argon flow rate of 17 L / min, additive manufacturing is performed on the AZ31 magnesium alloy substrate obtained in step 1 using AZ31 magnesium alloy welding wire. The additive manufacturing process is as follows: the vertical distance between the welding gun and the AZ31 substrate is adjusted to 15 mm, the welding gun moves in a cyclic zigzag swing mode, the swing radius is 5 mm, the spacing between any two adjacent zigzag centers during the zigzag swing process is 6 mm, the welding gun travels at a speed of 8 mm / s, the welding current is 125 A, the welding voltage is 15 V, and the wire feeding speed is 7.6 m / min. After each additive manufacturing layer, it is cooled to 75°C and polished to remove the impurity layer, and then the next layer of additive manufacturing is performed, and finally a 36-layer additively manufactured magnesium alloy 3 is obtained.

[0032] Comparative Example 2

[0033] The preparation method of additively manufactured magnesium alloy 4 is as follows:

[0034] AZ31 magnesium alloy substrate and ZK60 magnesium alloy welding wire with a wire diameter of 1.2mm are used;

[0035] Step 1: Polish the surface of the AZ31 magnesium alloy substrate with sandpaper and clean it with anhydrous ethanol, and then use a hair dryer to dry it to remove stains and oxide layers on the surface of the AZ31 magnesium alloy substrate to obtain an AZ31 magnesium alloy substrate with a clean surface.

[0036] Step 2: The magnesium alloy substrate obtained in step (1) is fixed on an additive manufacturing workbench. Under argon protection with an argon flow rate of 19 L / min, ZK60 magnesium alloy welding wire is used to perform additive manufacturing on the AZ31 magnesium alloy substrate obtained in step 1. The additive manufacturing is as follows: the vertical distance between the welding gun and the AZ31 substrate is adjusted to 13 mm, the welding gun moves in a straight line, the welding gun travel speed is 6 mm / s, the welding current is 105 A, the welding voltage is 16 V, and the wire feed speed is 8 m / min. After each additive manufacturing layer, it is cooled to 80°C and polished to remove the impurity layer, and then the next layer of additive manufacturing is performed, and finally a 34-layer additively manufactured magnesium alloy 4 is obtained.

[0037] Comparative Example 3

[0038] The preparation method of heterogeneous magnesium alloy 5 is as follows:

[0039] AZ31 magnesium alloy substrate, AZ31 and ZK60 magnesium alloy welding wire with a wire diameter of 1.0mm;

[0040] Step 1: Polish the surface of the AZ31 magnesium alloy substrate with sandpaper and clean it with anhydrous ethanol, and then use a hair dryer to dry it to remove stains and oxide layers on the surface of the AZ31 magnesium alloy substrate to obtain an AZ31 magnesium alloy substrate with a clean surface.

[0041] Step 2: The magnesium alloy substrate obtained in step (1) is fixed on an additive manufacturing workbench. Under a shielding gas, the shielding gas is 99.9% pure argon gas at a shielding gas flow rate of 30 L / min, and AZ31 and ZK60 magnesium alloy welding wires are used to perform alternating additive manufacturing on the magnesium alloy substrate. The alternating additive manufacturing is alternating between zigzag and straight line additive manufacturing. Among them, the zigzag additive manufacturing: the vertical distance between the welding gun and the substrate is adjusted to 9 mm, and AZ31 magnesium alloy welding wire is first used for additive manufacturing. The welding gun moves in a cyclic zigzag swing manner with a swing radius of 12 mm. During the zigzag swing process, the interval between any two adjacent zigzag lines is 1.5 mm, the welding gun travels at a speed of 2.5 mm / s, the welding current is 85 A, the welding voltage is 11.6 V, and the wire feeding speed is 3.6 m / min. After adding 2 layers, it is cooled to 40°C and polished to remove impurities; the linear additive manufacturing: ZK60 magnesium alloy welding wire is used for additive manufacturing, the welding gun moves in a straight line manner, the welding gun travels at a speed of 3.5 mm / s, the welding current is 70 A, the welding voltage is 12.6 V, and the wire feeding speed is 4.5 m / min. After completing 2 layers of additive manufacturing, it is cooled to 45°C, polished to remove impurities, and then alternating additive manufacturing is performed on the magnesium alloy substrate according to the above-mentioned two magnesium alloy welding wires. This cycle is repeated to finally obtain 20 layers of heterogeneous magnesium alloy 5.

[0042] Table 1 Comparison of component performance obtained in Examples 1-2 and Comparative Examples 1-3

[0043]

[0044] As can be seen from Table 1, the number of layers of Examples 1 and 2 is higher than that of Comparative Examples 1, 2 and 3. According to prior art reports, the higher the number of layers, the worse the performance, but the strength and plasticity of the alloys obtained in Examples 1 and 2 are higher than those obtained in Comparative Examples 1-3. Moreover, the performance is poor when only AZ31 magnesium alloy welding wire is used for additive manufacturing, such as Comparative Example 1. However, when two magnesium alloy welding wires are used for alternating additive manufacturing, the mechanical properties (Examples 1 and 2) are significantly improved compared to the strength and plasticity of a single AZ31 magnesium alloy (Comparative Example 1), and exceed the mechanical properties of a single ZK60 magnesium alloy additive component (Comparative Example 2). In addition, according to prior art reports, when heterogeneous welding wires are used for additive manufacturing, it is difficult to increase strength and plasticity simultaneously, that is, when strength is increased, plasticity will be reduced. By comparison, the present invention has achieved unexpected technical effects compared with the prior art, not only in terms of strength, but also in terms of plasticity, achieving a simultaneous improvement in strength and plasticity. Furthermore, while Comparative Example 3 uses the same alloy and process as the present invention, the relevant process parameters are outside the scope of the present invention's claims. Nevertheless, its strength and ductility are both lower than the minimum performance of the material obtained by the present invention. This demonstrates that even though a similar process to the present invention is used, simultaneous improvements in the strength and ductility of dissimilar materials in additive manufacturing can only be achieved within the scope of the present invention's claims.

[0045] The present invention achieves additive manufacturing of dissimilar welding wires through the coordinated control of welding wire, substrate, process, and process parameters. This effectively addresses the existing problems faced by the prior art: when alternating two welding wires for additive manufacturing, poor interface bonding between the different materials can lead to breakage, resulting in poor compatibility between the two components, leading to delamination and anisotropy during the additive process. This ultimately leads to decreased mechanical properties, uneven distribution of mechanical properties, difficulty in simultaneously improving the strength and ductility of the additively manufactured material, and the inability of a single welding wire to meet the technical challenges of different performance requirements at different locations. While achieving performance superior to that of single-component additively manufactured components, the present invention simplifies the process and reduces raw material costs without adding rare earth or high-content elements. This significantly improves the strength and ductility of the additively manufactured material, achieving performance comparable to that of materials containing rare earth elements, and simultaneously improving the strength and ductility of the alloy, exceeding the strength and ductility of any of the components. Furthermore, the additively manufactured material achieves a microstructure characterized by good interface bonding, good compatibility, and stable performance, effectively suppressing delamination and local and global anisotropy, making it suitable for the industrial production of additively manufactured materials with uniform performance or varying performance at different locations.

Claims

1. A high performance heterogeneous magnesium alloy, characterized in that: Its additive manufacturing method includes the following steps: (1) polishing the surface of the magnesium alloy substrate with sandpaper and cleaning it with anhydrous ethanol, and then drying it with a hair dryer to remove stains and an oxide layer on the surface of the magnesium alloy substrate to obtain a magnesium alloy substrate with a clean surface; (2) The magnesium alloy substrate obtained in step (1) is fixed on an additive manufacturing workbench, and under a protective gas, the protective gas flow rate is 10-28 L / min, and magnesium alloy welding wire 1 and magnesium alloy welding wire 2 are used to perform alternating additive manufacturing on the magnesium alloy substrate; the alternating additive manufacturing is: alternating folded line and straight line additive manufacturing; wherein the folded line additive manufacturing: the vertical distance between the welding gun and the substrate is adjusted to 10-26 mm, firstly, magnesium alloy welding wire 1 is used for additive manufacturing, and the welding gun moves in a folded line swinging manner, the swing radius is 2-11 mm, and the distance between any two adjacent folded line centers during the folded line swinging process is 2-8 mm, the travel speed of the welding gun is 3-15 mm / s, and the welding current is 9 0-150A, welding voltage is 12-26V, wire feeding speed is 4-20m / min, after additive manufacturing 1-10 layers, cooling to 50-120°C, grinding to remove impurities; the linear additive manufacturing: using magnesium alloy welding wire 2 for additive manufacturing, the welding gun moves in a straight line, the welding gun travel speed is 4-16mm / s, the welding current is 75-150A, the welding voltage is 13-27V, the wire feeding speed is 5-22m / min, after additive manufacturing 1-10 layers, cooling to 55-125°C, grinding to remove impurities, and then performing alternating additive manufacturing on the magnesium alloy substrate according to broken line additive manufacturing and linear additive manufacturing; repeating this cycle, and finally obtaining 30-80 layers of high-performance heterogeneous magnesium alloy; The magnesium alloy described in step (1) is one of AZ31 magnesium alloy, AZ51 magnesium alloy, ZK60 magnesium alloy or ZK61 magnesium alloy; the protective gas described in step (2) is high-purity argon gas with a purity of ≥99.99% or a mixture of argon and helium or a mixture of CO2 and argon; the volume ratio of argon to helium is 1.5-3:7-8.5; the volume ratio of CO2 to argon is 2-5:95-98; The diameter of the magnesium alloy welding wire 1 is 1.1-6.0 mm; The diameter of the magnesium alloy welding wire 2 is 1.2-5.8 mm; The magnesium alloy welding wire 1 is one of AZ31 magnesium alloy welding wire and AZ51 magnesium alloy welding wire; The magnesium alloy welding wire 2 is one of ZK60 magnesium alloy welding wire and ZK61 magnesium alloy welding wire.

2. A high performance heterogeneous magnesium alloy according to claim 1, characterized in that: The vertical distance between the welding gun and the substrate in step (2) is 11-19 mm.

3. The high performance heterogeneous magnesium alloy according to claim 1, characterized in that: The fold line additive manufacturing described in step (2): the swing radius is 3-10 mm, the spacing between any two adjacent fold line centers during the fold line swing process is 3-7 mm, the welding gun travel speed is 4-14 mm / s, the welding current is 95-145 A, the welding voltage is 13-25 V, and the wire feeding speed is 5-19 m / min.

4. The high performance heterogeneous magnesium alloy according to claim 1, characterized in that: The linear additive manufacturing described in step (2) is as follows: the travel speed of the welding gun is 5-13 mm / s, the welding current is 80-140 A, the welding voltage is 14-25 V, and the wire feeding speed is 6-21 m / min.

5. The high performance heterogeneous magnesium alloy according to claim 1, characterized in that: The step (2) finally obtains 32-76 layers of high-performance heterogeneous magnesium alloy.

Images