A plasma arc fuse additive manufacturing method for high-performance rare earth magnesium alloy

Abstract

The present invention discloses a plasma arc fused additive manufacturing method for high-performance rare earth magnesium alloys. The manufacturing method comprises the following steps: Step 1: pre-deposition preparation; Step 2: deposition forming; and Step 3: in-situ static cooling in an argon atmosphere to produce a ZM6 magnesium alloy workpiece. By utilizing plasma, which has a more stable heat input, as a heat source for additive manufacturing of ZM6 magnesium alloys, the manufacturing method of the present invention can reduce the volatilization of alloying elements and melt splashing, avoid the generation of defects such as pores, and avoid the high cost, internal shrinkage cavities, and inclusions associated with traditional casting methods for manufacturing ZM6 magnesium alloy workpieces. The method is suitable for the field of metal additive manufacturing technology.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal additive manufacturing, and in particular relates to a plasma arc fuse additive manufacturing method for a high-performance rare earth magnesium alloy. Background Art

[0002] ZM6 magnesium alloy (Mg-(2.0-2.8)Nd-(0.1-0.7)Zn-(0.4-1.0)Zr) is a typical cast Mg-RE alloy. Nd has a large solid solubility in Mg and its solubility varies significantly with temperature. Furthermore, Nd readily forms the Mg12Nd intermetallic compound in Mg, which is relatively stable at high temperatures, resists growth, and exhibits high hot hardness. Therefore, ZM6 alloy offers advantages such as excellent room temperature performance, high heat resistance, and excellent heat treatment strengthening effects, making it a widely used cast magnesium alloy for the manufacture of complex and special-shaped parts.

[0003] However, currently, the industry mainly uses casting to prepare complex ZM6 magnesium alloy workpieces. On the one hand, due to the characteristics of the casting process, problems such as shrinkage cavities, insufficient pouring, and inclusions exist in the workpieces, affecting the mechanical properties of the workpieces. On the other hand, casting requires molds, and magnesium melt causes relatively large damage to the molds, resulting in higher costs for castings.

[0004] Additive manufacturing (AM), an emerging manufacturing technology, is based on the design of three-dimensional (3D) data models and creates 3D objects through layer-by-layer processing. It offers advantages such as short manufacturing cycles, high material utilization, high design freedom, excellent mechanical properties, and the ability to manufacture complex structural components. Combining the high specific stiffness and strength of magnesium alloys with the technical advantages of AM for high-performance forming of complex structural components, the resulting AM materials offer significant potential and broad application prospects in high-tech industries such as automotive, aerospace, consumer electronics, and biomedicine.

[0005] Currently, additive manufacturing technologies are primarily categorized into selective laser melting (SLM), electron beam selective melting (EBSM), laser near-net shaping (LENS), and wire arc additive manufacturing (WAAM), based on the raw material delivery method, type, and heat source. Arc-fuse additive manufacturing boasts high production efficiency and can rapidly produce large-scale components, with no restrictions on product size. Furthermore, Mg alloy powders have low evaporation temperatures, high vapor pressures, and are flammable and explosive. Using ZM6 magnesium alloy wire as raw material, arc-fuse additive manufacturing (WAAM) makes component manufacturing safer and more reliable, enabling autonomous control. Furthermore, compared to traditional manufacturing, WAAM significantly shortens component manufacturing time. Furthermore, the technology requires no molds, boasts a high degree of automation, and boasts high efficiency. It can rapidly produce components of varying sizes and shapes, with no spatial restrictions on product size. Therefore, arc-fuse additive manufacturing is an ideal method for producing ZM6 magnesium alloy components. Summary of the Invention

[0006] The present invention aims to overcome the shortcomings of the prior art by providing a plasma arc fuse additive manufacturing method for high-performance rare earth magnesium alloys. This method utilizes plasma, which offers a more stable heat input, as a heat source for additive manufacturing of ZM6 magnesium alloys. This method reduces the volatilization of alloying elements and melt spatter, avoiding defects such as porosity, and addresses the high cost, internal shrinkage cavities, and inclusions associated with traditional casting methods for ZM6 magnesium alloy workpieces.

[0007] To achieve the above objectives, the present invention adopts a technical solution: a method for additively manufacturing a high-performance rare earth magnesium alloy plasma arc fuse, characterized in that the method uses plasma arc fuse additive manufacturing equipment, uses ZM6 magnesium alloy wire as raw material, and follows the following steps:

[0008] Step 1: Preparation before deposition:

[0009] Step 101: Using a ZM6 magnesium alloy plate as a substrate, pre-depositing a single pass of ZM6 magnesium alloy on the substrate to obtain deposition parameters;

[0010] Step 102: Using computer software to create a three-dimensional model of the target ZM6 magnesium alloy workpiece, slicing the three-dimensional model to obtain layer data, and simulating a deposition path. The deposition path and the deposition parameters obtained in step 101 are then imported into a plasma arc fuse additive manufacturing device.

[0011] Step 103: Fix the substrate on a workbench of a plasma arc fuse additive manufacturing device, use the upper surface of the substrate as a reference surface for additive manufacturing, adjust the vertical distance between the plasma arc welding gun head and the substrate to 8 mm to 20 mm, and then preheat the substrate;

[0012] Step 104: Fix the ZM6 magnesium alloy wire reel in the wire feeding system, adjust the angle between the wire outlet of the wire feeding system and the upper surface of the substrate, and the distance from the plasma arc welding gun head, and coaxially introduce argon gas at a flow rate of 15 L / min to 30 L / min as a shielding gas into the plasma arc welding gun;

[0013] Step 2: Deposition forming: Start the wire feeding system, turn on the plasma arc welding gun, introduce argon gas, and deposit on the substrate preheated in step 103 to obtain a ZM6 magnesium alloy deposited part;

[0014] Step 3: Cool the ZM6 magnesium alloy deposit obtained in step 2 in situ under an argon atmosphere to obtain a ZM6 magnesium alloy workpiece.

[0015] By using high-heat-input plasma as a heat source, this method can bring the melting rates of high-melting-point rare earth elements in ZM6 magnesium alloy closer to those of various other low-melting-point metal elements, improving deposition efficiency and reducing second-phase segregation and volatilization of low-melting-point alloying elements during the deposition process. Multiple single-pass depositions are performed, and the morphology and dimensions of each pass are compared to optimize deposition parameters.

[0016] The above-mentioned plasma arc fuse additive manufacturing method for a high-performance rare earth magnesium alloy is characterized in that the deposition parameters described in step 101 are specifically: input current 160A~220A, arc voltage 9.3V~9.9V, wire feeding speed 1800mm / min~2200mm / min, and plasma arc welding gun head travel speed 190mm / min~220mm / min.

[0017] The invention controls the heat input, wire feeding speed and travel speed of the deposition process according to the characteristics of the ZM6 magnesium alloy, such as the large variety and high content of alloying elements in the ZM6 magnesium alloy and the high melting point rare earth elements, which lead to the large number of precipitated phases of the ZM6 magnesium alloy and the easy occurrence of second phase segregation and volatilization of low melting point alloying elements during the deposition process. The input current and arc voltage are regulated by the wall thickness of the deposited part and the diameter of the ZM6 magnesium alloy wire to control the energy of the plasma heat source, thereby controlling the degree of melting of the ZM6 magnesium alloy wire and the size of the heat affected zone on the deposited part. The deposition speed is controlled by controlling the wire feeding speed and travel speed to avoid the problems of over-feeding, resulting in surfacing, insufficient melting of the ZM6 magnesium alloy wire and the occurrence of unmelted particles, and a narrow deposition single path, resulting in a small contact area between the deposited layers and weak interlayer bonding strength. The invention also avoids the problems of over-feeding, resulting in excessive melting of the ZM6 magnesium alloy wire and a large heat affected zone, volatilization of low melting point elements, affecting the alloy composition, and excessive melting making it difficult to form the deposited part.

[0018] The above-mentioned plasma arc fuse additive manufacturing method of a high-performance rare earth magnesium alloy is characterized in that the diameter of the ZM6 magnesium alloy wire in the ZM6 magnesium alloy wire coil in step 104 is 0.8 mm to 1.6 mm.

[0019] By controlling the diameter of the ZM6 magnesium alloy wire to 0.8 mm to 1.6 mm, the present invention facilitates control of the molten pool width and the size of a single-pass deposition, thereby controlling the size of the deposited part, while also balancing deposition efficiency and quality, and ensuring complete melting of the ZM6 magnesium alloy wire during the deposition process. This avoids the situation where an overly thin ZM6 magnesium alloy wire reduces the width of the molten pool, resulting in reduced deposition efficiency, while an overly thick ZM6 magnesium alloy wire increases the molten pool width, resulting in reduced dimensional accuracy of the deposited part and failing to ensure complete melting of the ZM6 magnesium alloy wire during the deposition process.

[0020] The above-mentioned plasma arc fuse additive manufacturing method of a high-performance rare earth magnesium alloy is characterized in that the thickness of the ZM6 magnesium alloy plate in step 101 is 10 mm to 30 mm.

[0021] The present invention controls the thickness of the ZM6 magnesium alloy plate to be 10 mm to 30 mm, so that the ZM6 magnesium alloy plate is not easily deformed after heating, and is conducive to heating and heat preservation, saving materials and energy; in addition, the ZM6 magnesium alloy plate used as a substrate can be repeatedly used, and when the thickness of the substrate is less than 10 mm, it is replaced.

[0022] The above-mentioned plasma arc fuse additive manufacturing method for a high-performance rare earth magnesium alloy is characterized in that the preheating temperature of the substrate in step 103 is 150°C to 250°C.

[0023] The present invention controls the cooling rate of the deposition molten pool by controlling the preheating temperature, thereby avoiding the phenomenon of unfused (pores) during the deposition process; and simultaneously avoids the generation of internal stress in the deposition part due to rapid cooling.

[0024] The above-mentioned plasma arc fuse additive manufacturing method of a high-performance rare earth magnesium alloy is characterized in that the deposition process in step 2 is as follows: when the target ZM6 magnesium alloy workpiece is a prism with a wall thickness of less than 10 mm, direct deposition is performed using a single-pass or double-pass reciprocating straight line or curved path until a first deposition layer is obtained; when the wall thickness is greater than 10 mm and direct deposition cannot be performed using a single-pass or double-pass path, deposition is first performed using a "bow"-shaped reciprocating straight line or curved path to complete deposition of the entire interior surface of the first layer, and then deposition is performed along the outer contour of the workpiece until the first deposition layer is obtained, and then deposition is performed layer by layer in the same manner to obtain a formed part, with the outer contour deposition thickness being higher than the inner portion;

[0025] When the target ZM6 magnesium alloy workpiece is an impeller, arc-shaped deposition is first performed on the inner ring of the impeller. After completing one circle of deposition on the inner ring, symmetrical blades are deposited in a reciprocating straight line. Then, one circle of deposition is performed along the inner and outer contours of the impeller to obtain the first deposition layer, and then the formed part is obtained by deposition layer by layer in the same way.

[0026] The present invention can avoid edge collapse when the second layer is deposited by controlling the outer contour to be higher than the inner contour.

[0027] The above-mentioned plasma arc fuse additive manufacturing method for a high-performance rare earth magnesium alloy is characterized in that after the deposition pool of each deposition layer solidifies, the surface of the deposition layer is immediately polished by a grinding and polishing machine.

[0028] The present invention adopts a grinding and polishing machine to polish the surface of the deposited layer, and combines the argon gas introduced during the deposition process as a protective gas to prevent the presence of an oxide layer or inclusion problems on the surface; the temperature of the deposited layer before grinding is higher than the preheating temperature of the substrate and has been solidified, which can ensure the dimensional accuracy of the deposited layer, is conducive to deposition molding, and can avoid the problem of collapse and inability to form due to the unsolidified molten pool at high temperature, while ensuring a fine grain size.

[0029] The above-mentioned plasma arc fuse additive manufacturing method for a high-performance rare earth magnesium alloy is characterized in that the path of each deposition layer of the formed part is 0° to 90° with the adjacent deposition layer.

[0030] The present invention forms an angle between the deposited layers to form an interlocking structure between the deposited layers, which is beneficial to controlling the dimensional accuracy of the deposited parts and eliminating the anisotropy of the deposited parts, thereby maintaining the isotropy of mechanical properties.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] 1. The present invention uses plasma with a more stable heat input as a heat source for additive manufacturing of ZM6 magnesium alloy. Compared with additive manufacturing methods using magnesium alloy powder as raw materials, the operation is safe and reliable, and problems such as volatilization of alloying elements can be avoided. Compared with methods such as metal inert gas shielded welding, the heat input in the additive manufacturing process of the present invention is more stable and can reduce spatter and the generation of defects such as pores. It effectively avoids problems such as arc instability during additive manufacturing cladding deposition and molten pool overflow and collapse during forming. As a result, high-performance ZM6 magnesium alloy workpieces with dense internal structure, fine grains, a large number of fine precipitates, and excellent tensile properties in various parts are obtained.

[0033] 2. The plasma arc fuse additive manufacturing process of this invention offers flexible parameter adjustment, a high degree of intelligence, safety, reliability, and high deposition efficiency. The magnesium alloy components produced using this method exhibit fine grains, a uniform and dense structure, and excellent mechanical properties. This method also avoids problems such as structural inhomogeneity, porosity, crack defects, and internal stress in cast alloys, eliminating mold costs.

[0034] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Schematic diagram of the process principle of the manufacturing method of the present invention.

[0036] Figure 2 Schematic diagram of the deposition path of Example 1 of the present invention.

[0037] Figure 3 This is a physical picture of the ZM6 magnesium alloy workpiece obtained in Example 1 of the present invention.

[0038] Figure 4 This is a physical picture of the internal cross-section of the ZM6 magnesium alloy workpiece obtained in Example 1 of the present invention.

[0039] Figure 5 This is a microstructure diagram of a ZM6 magnesium alloy workpiece at a height of 0 mm to 10 mm obtained in Example 1 of the present invention.

[0040] Figure 6 This is a microstructure diagram of a ZM6 magnesium alloy workpiece at a height of 45 mm to 55 mm obtained in Example 1 of the present invention.

[0041] Figure 7 This is a microstructure diagram of a ZM6 magnesium alloy workpiece at a height of 90 mm to 100 mm obtained in Example 1 of the present invention.

[0042] Figure 8 This is a physical picture of the appearance and cross-section of the ZM6 magnesium alloy workpiece obtained in Example 2 of the present invention.

[0043] Figure 9 This is a microstructure diagram of the center position of the blade of the ZM6 magnesium alloy workpiece obtained in Example 2 of the present invention.

[0044] Figure 10 Microstructure diagram of the inner ring position of the ZM6 magnesium alloy workpiece obtained in Example 2 of the present invention. DETAILED DESCRIPTION

[0045] Example 1

[0046] like Figure 1As shown, the manufacturing method of this embodiment adopts plasma arc fuse additive manufacturing equipment, uses ZM6 magnesium alloy wire as raw material, and is carried out according to the following steps:

[0047] Step 1: Preparation before deposition:

[0048] Step 101: Using a ZM6 magnesium alloy wire with a diameter of 1.6 mm as a raw material and a ZM6 magnesium alloy plate with a thickness of 20 mm as a substrate, multiple single-pass ZM6 magnesium alloy depositions are performed on the substrate in advance. Deposition parameters are adjusted based on the smoothness of the appearance of the single-pass deposited layer and the uniformity of the weld bead thickness. The ZM6 magnesium alloy wire is composed of the following components by mass percentage: Nd 2.37%, Zn 0.46%, Zr 0.63%, and the remainder Mg. The deposition parameters are specifically: input current 190 A, arc voltage 9.6 V, wire feed speed 1800 mm / min, and plasma arc welding gun tip travel speed 200 mm / min.

[0049] Step 102: Using computer software to perform three-dimensional modeling of the target ZM6 magnesium alloy workpiece, slicing the three-dimensional model to obtain layer data, and simulating an optimal deposition path. The deposition path and the deposition parameters obtained in step 101 are introduced into a plasma arc fuse additive manufacturing device; the target ZM6 magnesium alloy workpiece is a cube with dimensions of 100 mm × 100 mm × 100 mm;

[0050] Step 103: Fix the substrate on a workbench of the plasma arc fuse additive manufacturing equipment, use the upper surface of the substrate as a reference surface for the plasma arc fuse additive manufacturing, adjust the vertical distance between the plasma arc welding gun head and the substrate to 12 mm ± 1 mm, and preheat the substrate to 160° C. ± 10° C.;

[0051] Step 104: Fix the ZM6 magnesium alloy wire reel in the wire feeding system, adjust the angle between the wire outlet of the wire feeding system and the upper surface of the substrate to 15°±2°, and the distance from the tip of the plasma arc welding gun to 8 mm±0.5 mm, and coaxially introduce argon gas at a flow rate of 20 L / min as a shielding gas into the plasma arc welding gun; the diameter of the ZM6 magnesium alloy wire in the ZM6 magnesium alloy wire reel is 1.6 mm;

[0052] Step 2, deposition forming: start the wire feeding system, turn on the plasma arc welding gun, introduce argon gas with a flow rate of 20L / min as the shielding gas, and deposit on the ZM6 magnesium alloy substrate preheated in step 103, so that the ZM6 magnesium alloy wire is deposited in a straight line in a "bow" shape to complete the deposition of the entire inner surface of the first layer, and then deposited along the outer contour of the workpiece until the first deposition layer is obtained; after the deposition pool of the first deposition layer solidifies, the surface of the first deposition layer is immediately polished by a grinder, and then the deposition path is rotated 90°, maintaining a 90° angle with the first deposition layer path, and then the second layer is deposited in a straight line in a "bow" shape to complete the deposition of the entire inner surface of the second layer, and then deposited along the outer contour for a circle until the second deposition layer is obtained and polished; the deposition path of the third deposition layer is consistent with the first deposition layer, and is at a 90° angle to the second layer, as shown in FIG. Figure 2 As shown, by analogy, a ZM6 magnesium alloy deposited part is obtained by depositing and polishing layer by layer; the outer contour deposition thickness is higher than the inner contour;

[0053] Step 3: The ZM6 magnesium alloy deposit obtained in step 3 is cooled in situ under an argon atmosphere to obtain a ZM6 magnesium alloy workpiece with a size of 105 mm × 105 mm × 105 mm. Figure 3 shown.

[0054] The ZM6 magnesium alloy workpiece obtained in this embodiment was cut, and the longitudinal section morphology was as follows: Figure 4 As shown, the surface is smooth and bright, and the internal structure is dense, without porosity and unfused defects; samples were taken in the horizontal, vertical and 45° directions of the longitudinal section of the ZM6 magnesium alloy workpiece for tensile strength testing. The room temperature tensile properties in the three directions are similar, and the average room temperature tensile properties are: yield strength 125MPa±6MPa, tensile strength 210MPa±10MPa, and elongation 18%±2%; the microstructure analysis of the 0mm~10mm, 45mm~55mm, and 90mm~100mm height positions of the longitudinal section of the ZM6 magnesium alloy workpiece was carried out, as shown Figures 5 to 7 It can be seen that the structure of the ZM6 magnesium alloy workpiece block is very dense, the grains are fine, and a large number of fine precipitated phases are precipitated in the structure.

[0055] Example 2

[0056] The manufacturing method of this embodiment includes the following steps:

[0057] Step 1: Preparation before deposition:

[0058] Step 101: Using a ZM6 magnesium alloy wire with a diameter of 0.8 mm as a raw material and a ZM6 magnesium alloy plate with a thickness of 15 mm as a substrate, a single-pass ZM6 magnesium alloy deposition is performed on the substrate in advance. Deposition parameters are adjusted based on the smoothness of the single-pass deposited layer and the uniformity of the weld bead thickness. The ZM6 magnesium alloy wire is composed of the following components by mass percentage: Nd 2.37%, Zn 0.46%, Zr 0.63%, and the remainder Mg. The deposition parameters are specifically: input current 170 A, arc voltage 9.4 V, wire feed speed 2000 mm / min, and plasma arc welding gun tip travel speed 200 mm / min.

[0059] Step 102: Using computer software to perform three-dimensional modeling of the target ZM6 magnesium alloy workpiece, slicing the three-dimensional model to obtain layer data, and simulating an optimal deposition path. The deposition path and the deposition parameters obtained in step 101 are introduced into a plasma arc fuse additive manufacturing device; the target ZM6 magnesium alloy workpiece is an impeller, and the maximum diameter of the impeller blades is 150 mm, the inner ring diameter is 40 mm, and the width of a single blade and the inner ring width are both 10 mm;

[0060] Step 103: Fix the substrate on a workbench of the plasma arc fuse additive manufacturing equipment, use the upper surface of the substrate as a reference surface for the plasma arc fuse additive manufacturing, adjust the vertical distance between the plasma arc welding gun head and the substrate to 15 mm ± 1 mm, and preheat the substrate to 170° C. ± 10° C.;

[0061] Step 104: Fix the ZM6 magnesium alloy wire reel in the wire feeding system, adjust the angle between the wire outlet of the wire feeding system and the upper surface of the substrate to 10°±2°, and the distance from the tip of the plasma arc welding gun to 10 mm±0.5 mm, and coaxially introduce argon gas at a flow rate of 15 L / min as a shielding gas into the plasma arc welding gun; the diameter of the ZM6 magnesium alloy wire in the ZM6 magnesium alloy wire reel is 0.8 mm;

[0062] Step 2: Deposition forming: Start the wire feeding system, turn on the plasma arc welding gun, introduce argon gas with a flow rate of 15L / min as the shielding gas, and perform deposition on the ZM6 magnesium alloy substrate preheated in step 103, as shown in FIG. Figure 1 As shown, the ZM6 magnesium alloy wire is first deposited in an arc shape on the inner ring of the impeller. After completing one circle of deposition on the inner ring, symmetrical blades are deposited in a reciprocating straight line. Subsequently, one circle of deposition is performed along the inner and outer contours of the impeller. After the deposition pool of the first deposition layer solidifies, the surface of the first deposition layer is immediately polished by a grinding and polishing machine to obtain the first deposition layer. The impeller formed part is obtained by depositing and polishing layer by layer along the path of the first deposition layer.

[0063] Step 3: The ZM6 magnesium alloy deposit obtained in step 3 is cooled in situ under an argon atmosphere to obtain a ZM6 magnesium alloy workpiece with a maximum diameter of 160 mm for the impeller blade, an inner ring diameter of 35 mm, and a single blade width and an inner ring width of 15 mm. Figure 8 shown.

[0064] The microstructure of the blade center and inner ring of the ZM6 magnesium alloy workpiece obtained in this embodiment was analyzed respectively. Figure 9 and Figure 10 It can be seen that the blades and inner ring of the ZM6 magnesium alloy workpiece have dense structures, without porosity and unfused defects, and there are a large number of precipitated phases in the structure.

[0065] Example 3

[0066] The manufacturing method of this embodiment includes the following steps:

[0067] Step 1: Preparation before deposition:

[0068] Step 101: Using a ZM6 magnesium alloy wire with a diameter of 1.0 mm as a raw material and a ZM6 magnesium alloy plate with a thickness of 10 mm as a substrate, multiple single-pass ZM6 magnesium alloy depositions are performed on the substrate in advance. Deposition parameters are adjusted based on the smoothness of the appearance of the single-pass deposited layer and the uniformity of the weld bead thickness. The ZM6 magnesium alloy wire is composed of the following components by mass percentage: Nd 2.37%, Zn 0.46%, Zr 0.63%, and the remainder Mg. The deposition parameters are specifically: input current 160 A, arc voltage 9.3 V, wire feed speed 2200 mm / min, and plasma arc welding gun tip travel speed 220 mm / min.

[0069] Step 102: Using computer software to perform three-dimensional modeling of the target ZM6 magnesium alloy workpiece, slicing the three-dimensional model to obtain layer data, and simulating an optimal deposition path. The deposition path and the deposition parameters obtained in step 101 are introduced into a plasma arc fuse additive manufacturing device; the target ZM6 magnesium alloy workpiece is a cube with dimensions of 100 mm × 100 mm × 100 mm;

[0070] Step 103: Fix the substrate on a workbench of the plasma arc fuse additive manufacturing equipment, use the upper surface of the substrate as a reference surface for the plasma arc fuse additive manufacturing, adjust the vertical distance between the plasma arc welding gun head and the substrate to 12 mm ± 1 mm, and preheat the substrate to 200° C. ± 10° C.;

[0071] Step 104: Fix the ZM6 magnesium alloy wire reel in the wire feeding system, adjust the angle between the wire outlet of the wire feeding system and the upper surface of the substrate to 14°±2°, and the distance from the tip of the plasma arc welding gun to 8mm±0.5mm, and coaxially introduce argon gas at a flow rate of 30L / min as a shielding gas into the plasma arc welding gun. Figure 1 As shown; the diameter of the ZM6 magnesium alloy wire in the ZM6 magnesium alloy wire coil is 1.0 mm;

[0072] Step 2, deposition forming: start the wire feeding system, turn on the plasma arc welding gun, introduce argon gas with a flow rate of 30L / min as a shielding gas, and deposit on the ZM6 magnesium alloy substrate preheated in step 103, so that the ZM6 magnesium alloy wire is deposited in a straight line in a "bow" shape to complete the deposition of the entire inner surface of the first layer, and then deposited along the outer contour of the workpiece until the first deposition layer is obtained; after the deposition pool of the first deposition layer solidifies, the surface of the deposition layer is immediately polished by a grinder, and then the deposition path is rotated 45°, maintaining a 45° angle with the first deposition layer path, and then the second layer is deposited in a straight line in a "bow" shape to complete the deposition of the entire inner surface of the second layer, and then deposited along the outer contour for one circle until the second deposition layer is obtained and polished; the deposition path of the third deposition layer is consistent with the first deposition layer, and is at a 45° angle to the second layer, and so on, deposition and polishing layer by layer to obtain a formed part to obtain a ZM6 magnesium alloy deposition part; the deposition thickness of the outer contour is higher than that of the inner part;

[0073] Step 3: The ZM6 magnesium alloy deposited piece obtained in step 3 is left to cool in situ under an argon atmosphere to obtain a ZM6 magnesium alloy workpiece with a size of 103 mm×103 mm×103 mm.

[0074] The ZM6 magnesium alloy workpiece of this embodiment was sampled in the horizontal, vertical and 45° directions of the longitudinal section and subjected to tensile strength testing. The room temperature tensile properties in the three directions were similar, and the average room temperature tensile properties were: yield strength 126 MPa ± 6 MPa, tensile strength 212 MPa ± 10 MPa, and elongation 19% ± 2%.

[0075] Example 4

[0076] The manufacturing method of this embodiment includes the following steps:

[0077] Step 1: Preparation before deposition:

[0078] Step 101: Using a ZM6 magnesium alloy wire with a diameter of 1.6 mm as a raw material and a ZM6 magnesium alloy plate with a thickness of 30 mm as a substrate, multiple single-pass ZM6 magnesium alloy depositions are performed on the substrate in advance. Deposition parameters are adjusted based on the smoothness of the appearance of the single-pass deposited layer and the uniformity of the weld bead thickness. The ZM6 magnesium alloy wire is composed of the following components by mass percentage: Nd 2.37%, Zn 0.46%, Zr 0.63%, and the remainder Mg. The deposition parameters are specifically: input current 220 A, arc voltage 9.9 V, wire feed speed 1900 mm / min, and plasma arc welding gun tip travel speed 190 mm / min.

[0079] Step 102: Using computer software to perform three-dimensional modeling of the target ZM6 magnesium alloy workpiece, slicing the three-dimensional model to obtain layer data, and simulating an optimal deposition path. The deposition path and the deposition parameters obtained in step 101 are introduced into a plasma arc fuse additive manufacturing device; the target ZM6 magnesium alloy workpiece is a cube with dimensions of 100 mm × 100 mm × 100 mm;

[0080] Step 103: Fix the substrate on a workbench of the plasma arc fuse additive manufacturing equipment, use the upper surface of the substrate as a reference surface for the plasma arc fuse additive manufacturing, adjust the vertical distance between the plasma arc welding gun head and the substrate to 12 mm ± 1 mm, and preheat the substrate to 150° C. ± 10° C.;

[0081] Step 104: Fix the ZM6 magnesium alloy wire reel in the wire feeding system, adjust the angle between the wire outlet of the wire feeding system and the upper surface of the substrate to 14°±2°, and the distance from the tip of the plasma arc welding gun to 8mm±0.5mm, and coaxially introduce argon gas at a flow rate of 30L / min as a shielding gas into the plasma arc welding gun. Figure 1 As shown; the diameter of the ZM6 magnesium alloy wire in the ZM6 magnesium alloy wire coil is 1.6 mm;

[0082] Step 2, deposition forming: start the wire feeding system, turn on the plasma arc welding gun, introduce argon gas with a flow rate of 30L / min as a shielding gas, and deposit on the ZM6 magnesium alloy substrate preheated in step 103, so that the ZM6 magnesium alloy wire is deposited in a straight line in a "bow" shape to complete the deposition of the entire inner surface of the first layer, and then deposited along the outer contour of the workpiece until the first deposition layer is obtained; after the deposition pool of the first deposition layer solidifies, the surface of the deposition layer is immediately polished by a grinder, and then the deposition path is rotated 60°, maintaining a 60° angle with the first deposition layer path, and then the second layer is deposited in a straight line in a "bow" shape to complete the deposition of the entire inner surface of the second layer, and then deposited along the outer contour for one circle until the second deposition layer is obtained and polished; the deposition path of the third deposition layer is consistent with the first deposition layer, and is at a 60° angle to the second layer, and so on, deposition and polishing layer by layer to obtain a formed part to obtain a ZM6 magnesium alloy deposition part; the deposition thickness of the outer contour is higher than that of the inner part;

[0083] Step 3: The ZM6 magnesium alloy deposited piece obtained in step 3 is left to cool in situ under an argon atmosphere to obtain a ZM6 magnesium alloy workpiece with a size of 105 mm×105 mm×105 mm.

[0084] The ZM6 magnesium alloy workpiece of this embodiment was sampled in the horizontal, vertical and 45° directions of the longitudinal section and subjected to tensile strength testing. The room temperature tensile properties in the three directions were similar, and the average room temperature tensile properties were: yield strength 125 MPa ± 6 MPa, tensile strength 211 MPa ± 10 MPa, and elongation 18% ± 2%.

[0085] Example 5

[0086] The difference between this embodiment and embodiment 4 is that the preheating temperature in step 103 is 250°C ± 10°C.

[0087] The ZM6 magnesium alloy workpiece of this embodiment was sampled in the horizontal, vertical and 45° directions of the longitudinal section and subjected to tensile strength testing. The room temperature tensile properties in the three directions were similar, and the average room temperature tensile properties were: yield strength 125 MPa ± 6 MPa, tensile strength 212 MPa ± 10 MPa, and elongation 18% ± 2%.

[0088] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural transformation made to the above embodiment based on the technical essence of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A plasma arc fuse additive manufacturing method for high-performance rare earth magnesium alloy, characterized in that: The method uses plasma arc fused wire additive manufacturing equipment, uses ZM6 magnesium alloy wire as raw material, and follows the following steps: Step 1: Preparation before deposition: Step 101: Using a ZM6 magnesium alloy plate as a substrate, pre-depositing a single ZM6 magnesium alloy on the substrate to obtain deposition parameters; the deposition parameters are specifically: input current 160A-220A, arc voltage 9.3V-9.9V, wire feed speed 1800mm / min-2200mm / min, and plasma arc welding gun tip travel speed 190mm / min-220mm / min; the thickness of the ZM6 magnesium alloy plate is 10mm-30mm; Step 102: Using computer software to create a three-dimensional model of the target ZM6 magnesium alloy workpiece, slicing the three-dimensional model to obtain layer data, and simulating a deposition path. The deposition path and the deposition parameters obtained in step 101 are then imported into a plasma arc fuse additive manufacturing device. Step 103: Fix the substrate on a workbench of the plasma arc fuse additive manufacturing equipment, use the upper surface of the substrate as the additive manufacturing reference surface, adjust the vertical distance between the plasma arc welding gun head and the substrate to 8 mm to 20 mm, and then preheat the substrate; the preheating temperature of the substrate is 150° C. to 250° C.; Step 104: Fix the ZM6 magnesium alloy wire reel in the wire feeding system, adjust the angle between the wire outlet of the wire feeding system and the upper surface of the substrate, and the distance between the wire outlet and the plasma arc welding gun tip, and coaxially introduce argon gas at a flow rate of 15 L / min to 30 L / min as a shielding gas into the plasma arc welding gun; the diameter of the ZM6 magnesium alloy wire in the ZM6 magnesium alloy wire reel is 0.8 mm to 1.6 mm; Step 2, deposition forming: start the wire feeding system, turn on the plasma arc welding gun, introduce argon gas, and deposit on the substrate preheated in step 103 to obtain a ZM6 magnesium alloy deposited part; the deposition process is as follows: when the target ZM6 magnesium alloy workpiece is a prism with a wall thickness of less than 10 mm, direct deposition is performed using a single or double-pass reciprocating straight line or curved path until a first deposition layer is obtained; when the wall thickness is greater than 10 mm and direct deposition cannot be performed using a single or double-pass path, first deposit along a "bow"-shaped reciprocating straight line or curved path to complete deposition of the entire inner surface of the first layer, then deposit along the outer contour of the workpiece until the first deposition layer is obtained, and then deposit layer by layer in the same manner to obtain a formed part, with the outer contour deposited thicker than the inner part; When the target ZM6 magnesium alloy workpiece is an impeller, arc-shaped deposition is first performed on the inner ring of the impeller. After completing one circle of deposition on the inner ring, symmetrical blades are deposited in a reciprocating straight line. Subsequently, deposition is performed along the inner and outer contours of the impeller to obtain the first deposition layer. The formed part is then deposited layer by layer in the same way. Step 3: Cool the ZM6 magnesium alloy deposit obtained in step 2 in situ under an argon atmosphere to obtain a ZM6 magnesium alloy workpiece.

2. The plasma arc fuse additive manufacturing method of a high-performance rare earth magnesium alloy according to claim 1, characterized in that: After the molten pool of each deposition layer solidifies, the surface of the deposition layer is immediately polished by a grinding and polishing machine.

3. The plasma arc fuse additive manufacturing method of a high-performance rare earth magnesium alloy according to claim 1, characterized in that: The path of each deposition layer of the formed part is 0° to 90° with respect to the adjacent deposition layer.

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