Plasma arc fuse wire additive manufacturing method of high-performance rare earth magnesium alloy

Abstract

The invention discloses a plasma arc fuse wire additive manufacturing method of a high-performance rare earth magnesium alloy. The manufacturing method comprises the following steps: step 1, preparation before deposition; secondly, deposition forming is conducted; and thirdly, in-situ standing and cooling are conducted in the argon atmosphere, and the ZM6 magnesium alloy workpiece is obtained. According to the manufacturing method, the plasma with more stable heat input quantity is adopted as a heat source, ZM6 magnesium alloy additive manufacturing is carried out, volatilization of alloy elements and melt splashing can be reduced, air holes and other defects are avoided, the problems that a ZM6 magnesium alloy workpiece manufactured through a traditional casting method is high in cost, and shrinkage cavities and inclusions exist in the workpiece are solved, and the product quality is improved. The method is suitable for the technical field of metal additive manufacturing.

Description

Technical Field

[0001] The 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 casting Mg-RE alloy. Because Nd has a large solid solubility in Mg and changes greatly with temperature. At the same time, Nd easily forms Mg12Nd intermetallic compounds in Mg, which are relatively stable at high temperatures, not easy to grow, and have high hot hardness. Therefore, ZM6 alloy has the advantages of good room temperature performance, high heat resistance, and good heat treatment strengthening effect, making it a widely used casting magnesium alloy that can be used to manufacture complex shaped special-shaped parts.

[0003] However, currently, the industry mainly prepares complex ZM6 magnesium alloy workpieces by casting. 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, which affect the mechanical properties of the workpieces. On the other hand, casting requires molds, and the magnesium melt causes great damage to the mold, which leads to a high cost of the castings.

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

[0005] At present, according to the feeding method, type and heat source type of raw materials, additive manufacturing technology is mainly divided into selective laser melting (SLM), electron beam selective melting (EBSM), laser near-net shaping (LENS) and arc fuse additive manufacturing (WAAM). Among them, arc fuse additive manufacturing has high preparation efficiency, can quickly prepare large-size parts, and the product size is not limited; moreover, Mg alloy powder has the characteristics of low evaporation temperature, high vapor pressure, flammability and explosion. Arc fuse additive manufacturing uses ZM6 magnesium alloy wire as raw material, and the manufacturing of parts is safer and more reliable, and can achieve autonomous control. At the same time, compared with traditional manufacturing, WAAM greatly shortens the manufacturing time of parts, and this technology does not require molds, has a high degree of automation and high work efficiency, can quickly prepare parts of different sizes and shapes, and the product size is not limited by space. Therefore, arc fuse additive manufacturing is an ideal method for preparing ZM6 magnesium alloy parts. Summary of the invention

[0006] The purpose of the present invention is to overcome the deficiencies in the above-mentioned prior art and provide a plasma arc fuse additive manufacturing method for high-performance rare earth magnesium alloy. The manufacturing method adopts plasma with more stable heat input as a heat source for ZM6 magnesium alloy additive manufacturing, which can reduce the volatilization of alloy elements and melt splashing, avoid the generation of defects such as pores, and solve the problems of high cost, internal shrinkage cavities and inclusions in the traditional casting method for manufacturing ZM6 magnesium alloy workpieces.

[0007] To achieve the above object, the technical solution adopted by the present invention is: a plasma arc fuse additive manufacturing method for high-performance rare earth magnesium alloy, characterized in that the method adopts a plasma arc fuse additive manufacturing device, uses ZM6 magnesium alloy wire as a raw material, and is carried out according to the following steps:

[0008] Step 1: Preparation before deposition:

[0009] Step 101, using a ZM6 magnesium alloy plate as a substrate, preliminarily performing a single-pass ZM6 magnesium alloy deposition on the substrate to obtain deposition parameters;

[0010] Step 102: Use computer software to three-dimensionally model the target ZM6 magnesium alloy workpiece, slice the three-dimensional model to obtain layer data, and simulate the deposition path. The deposition path and the deposition parameters obtained in step 101 are introduced into the plasma arc fuse additive manufacturing equipment;

[0011] Step 103, fix the substrate on the 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;

[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 head of the plasma arc welding gun, and coaxially introduce argon gas with a flow rate of 15L / min to 30L / 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] The present invention uses plasma with high heat input as a heat source, which can make the melting speed of high-melting-point rare earth elements in ZM6 magnesium alloy close to that of other low-melting-point metal elements, which is beneficial to improve deposition efficiency and reduce the phenomenon of second phase segregation and volatilization of low-melting-point alloy elements during deposition. By performing multiple single-pass depositions, the appearance and size of each deposition pass are compared to optimize the 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 walking speed of the deposition process according to the characteristics that the ZM6 magnesium alloy has many kinds of alloy elements, high content and contains rare earth elements with high melting points, resulting in many precipitation phases of the ZM6 magnesium alloy, and the second phase segregation and low melting point alloy element volatilization are easy to occur 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 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 the walking speed to avoid the problem that the wire feeding speed is too fast to cause surfacing, the ZM6 magnesium alloy wire is not melted enough to cause the phenomenon of unmelting, and the deposition single channel is relatively narrow, so that the contact area between the deposited layers is small and the interlayer bonding strength is weak; the wire feeding speed is too slow to cause the ZM6 magnesium alloy wire to melt excessively and the heat affected zone is large, the low melting point elements volatilize, and the alloy composition is affected, and the transition melting makes the deposited part difficult to form.

[0018] The above-mentioned plasma arc fuse additive manufacturing method for 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] The present invention controls the diameter of the ZM6 magnesium alloy wire to be 0.8 mm to 1.6 mm, which is beneficial to controlling the width of the molten pool and the size of the single-pass deposition, thereby controlling the size of the deposited part, while taking into account both the deposition efficiency and the quality, and ensuring that the ZM6 magnesium alloy wire is completely melted during the deposition process. Avoiding too thin ZM6 magnesium alloy wire will reduce the width of the molten pool and reduce the deposition efficiency, while too thick ZM6 magnesium alloy wire will increase the width of the molten pool and reduce the dimensional accuracy of the deposited part, and at the same time cannot ensure that the ZM6 magnesium alloy wire is completely melted during the deposition process.

[0020] The above-mentioned plasma arc fuse additive manufacturing method for 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 can be used repeatedly as a substrate, 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 described in step 2 is: when the target ZM6 magnesium alloy workpiece is a prism, the wall thickness is less than 10 mm, and a single-channel or double-channel reciprocating straight line or curved path is used for direct deposition until the first deposition layer is obtained; when the wall thickness is greater than 10 mm and it is impossible to directly deposit by a single channel or a double channel, firstly deposit according to a "bow"-shaped reciprocating straight line or curved path to complete the deposition of the entire surface inside the first layer, and 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, and the deposition thickness of the outer contour is higher than that of the inner part;

[0025] When the target ZM6 magnesium alloy workpiece is an impeller, arc deposition is first performed on the inner ring of the impeller. After 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 to obtain the first deposition layer, and then layer by layer deposition is performed in the same manner to obtain the formed part.

[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, a grinding and polishing machine is immediately used to polish the surface of the deposition layer.

[0028] The present invention uses a grinder to grind 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 collapse and failure to form due to the failure of the molten pool to solidify at high temperature, while ensuring that the grain size is fine.

[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 the mechanical properties.

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

[0032] 1. The present invention uses plasma with more stable heat input as a heat source for ZM6 magnesium alloy additive manufacturing. Compared with the additive manufacturing method using magnesium alloy powder as raw material, the operation is safe and reliable, and the volatilization of alloy elements and other problems can be avoided. Compared with methods such as molten inert gas shielded welding, the heat input in the additive manufacturing process of the present invention is more stable and can reduce splashing, reduce the generation of defects such as pores, and effectively avoid problems such as arc instability during additive manufacturing cladding deposition and overflow and collapse of the molten pool during forming, thereby obtaining a high-performance ZM6 magnesium alloy workpiece with dense internal structure, fine grains, a large number of fine precipitated phases, and excellent tensile properties in various parts.

[0033] 2. The plasma arc fuse additive manufacturing process of the present invention has flexible adjustment of process parameters, high intelligence, safety and reliability, and high deposition efficiency; the magnesium alloy parts prepared by this method have fine grains, uniform and dense structure, and excellent mechanical properties. This method avoids problems such as uneven structure, pores, crack defects and internal stress in cast alloys, and saves 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 It is a 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] Fig. 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] Fig.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, pre-perform multiple single-pass ZM6 magnesium alloy depositions on the substrate, and adjust the deposition parameters according to the appearance smoothness of the single-pass deposition layer and the uniformity of the thickness of the weld bead; the ZM6 magnesium alloy wire is composed of the following components in mass percentage: Nd 2.37%, Zn 0.46%, Zr 0.63%, and the rest is Mg; the deposition parameters are specifically: input current 190A, arc voltage 9.6V, wire feeding speed 1800mm / min, and plasma arc welding gun head travel speed 200mm / min;

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

[0050] Step 103, fix the substrate on the workbench of the plasma arc fuse additive manufacturing equipment, use the upper surface of the substrate as the 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 gun head of the plasma arc welding gun to 8mm±0.5mm, and coaxially introduce argon gas with a flow rate of 20L / min into the plasma arc welding gun as a protective gas; the diameter of the ZM6 magnesium alloy wire in the ZM6 magnesium alloy wire reel is 1.6mm;

[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 deposit along the outer contour of the workpiece until the first deposition layer is obtained; after the deposition molten pool of the first deposition layer solidifies, immediately use a grinder to polish the surface of the first deposition layer, and then rotate the deposition path by 90°, maintaining a 90° angle with the first deposition layer path, and then deposit the second layer in a straight line in a "bow" shape to complete the deposition of the entire inner surface of the second layer, and then deposit one circle along the outer contour 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 with the second layer, such as Figure 2 As shown, by analogy, a ZM6 magnesium alloy deposition part is obtained by depositing and grinding layer by layer; the deposition thickness of the outer contour is higher than that of the inner contour;

[0053] Step 3: The ZM6 magnesium alloy deposit obtained in step 3 is cooled in situ in 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 is cut, and the longitudinal section morphology is as follows Figure 4 As shown, the surface is flat and bright, and the internal structure is dense, without pores 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 was performed on the 0mm~10mm, 45mm~55mm, and 90mm~100mm height positions of the longitudinal section of the ZM6 magnesium alloy workpiece, as shown Figure 5 to Figure 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, preliminarily performing a single-pass ZM6 magnesium alloy deposition on the substrate, and adjusting the deposition parameters according to the appearance smoothness of the single-pass deposition layer and the uniformity of the thickness of the weld bead; the ZM6 magnesium alloy wire is composed of the following components in mass percentage: Nd 2.37%, Zn 0.46%, Zr 0.63%, and the rest is Mg; the deposition parameters are specifically: input current 170A, arc voltage 9.4V, wire feeding speed 2000mm / min, and plasma arc welding gun head travel speed 200mm / min;

[0059] Step 102, using computer software to perform three-dimensional modeling on the target ZM6 magnesium alloy workpiece, slicing the three-dimensional model to obtain layer data, and simulating the optimal deposition path, and importing the deposition path and the deposition parameters obtained in step 101 into the plasma arc fuse additive manufacturing equipment; the target ZM6 magnesium alloy workpiece is an impeller, the maximum diameter of the impeller blade 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 the workbench of the plasma arc fuse additive manufacturing equipment, use the upper surface of the substrate as the 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 gun head of the plasma arc welding gun to 10mm±0.5mm, and coaxially introduce argon gas with a flow rate of 15L / min into the plasma arc welding gun as a protective gas; the diameter of the ZM6 magnesium alloy wire in the ZM6 magnesium alloy wire reel is 0.8mm;

[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, such as Figure 1 As shown, the ZM6 magnesium alloy wire is first deposited in an arc shape on the inner ring of the impeller, and after one circle of deposition of the inner ring is completed, symmetrical blades are deposited in a reciprocating straight line, and then one circle of deposition is performed along the inner and outer contours of the impeller. After the deposition molten 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; and then the first deposition layer is deposited and polished layer by layer to obtain an impeller formed part;

[0063] Step 3: The ZM6 magnesium alloy deposit obtained in step 3 is cooled in situ in an argon atmosphere to obtain a ZM6 magnesium alloy workpiece with a maximum diameter of 160 mm for the impeller blades, 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 microstructures of the blade center and inner ring of the ZM6 magnesium alloy workpiece obtained in this embodiment were analyzed respectively. Fig. 9 and Fig.10 It can be seen that the blades and inner ring of the ZM6 magnesium alloy workpiece have dense structures, without pores 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, pre-perform multiple single-pass ZM6 magnesium alloy depositions on the substrate, and adjusting the deposition parameters according to the appearance smoothness of the single-pass deposition layer and the uniformity of the thickness of the weld bead; the ZM6 magnesium alloy wire is composed of the following components in mass percentage: Nd 2.37%, Zn 0.46%, Zr 0.63%, and the rest is Mg; the deposition parameters are specifically: input current 160A, arc voltage 9.3V, wire feeding speed 2200mm / min, and plasma arc welding gun head travel speed 220mm / min;

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

[0070] Step 103, fix the substrate on the workbench of the plasma arc fuse additive manufacturing equipment, use the upper surface of the substrate as the 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 gun head of the plasma arc welding gun to 8mm±0.5mm, and coaxially introduce argon gas with a flow rate of 30L / min as a shielding gas into the plasma arc welding gun, such as 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 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 surface of the first layer, and then deposit 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 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 with the second layer, and so on, the ZM6 magnesium alloy deposition part is obtained by deposition and polishing layer by layer; the deposition thickness of the outer contour is higher than that of the inner part;

[0073] Step 3: Cool the ZM6 magnesium alloy deposit obtained in step 3 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 a tensile strength test. 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, pre-perform multiple single-pass ZM6 magnesium alloy depositions on the substrate, and adjusting the deposition parameters according to the appearance smoothness of the single-pass deposition layer and the uniformity of the thickness of the weld bead; the ZM6 magnesium alloy wire is composed of the following components in mass percentage: Nd 2.37%, Zn 0.46%, Zr 0.63%, and the rest is Mg; the deposition parameters are specifically: input current 220A, arc voltage 9.9V, wire feeding speed 1900mm / min, and plasma arc welding gun head travel speed 190mm / min;

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

[0080] Step 103, fix the substrate on the workbench of the plasma arc fuse additive manufacturing equipment, use the upper surface of the substrate as the 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 gun head of the plasma arc welding gun to 8mm±0.5mm, and coaxially introduce argon gas with a flow rate of 30L / min as a shielding gas into the plasma arc welding gun, such as 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 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 surface of the first layer, and then deposit 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 an angle of 60° 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 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 an angle of 60° with the second layer, and so on, the ZM6 magnesium alloy deposition part is obtained by deposition and polishing layer by layer; the deposition thickness of the outer contour is higher than that of the inner part;

[0083] Step 3: Cool the ZM6 magnesium alloy deposit obtained in step 3 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 a tensile strength test. 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 a tensile strength test. The room temperature tensile properties in the three directions were close, 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 still falls within the protection scope 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 fuse 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, preliminarily performing a single-pass ZM6 magnesium alloy deposition on the substrate to obtain deposition parameters; Step 102: Use computer software to three-dimensionally model the target ZM6 magnesium alloy workpiece, slice the three-dimensional model to obtain layer data, and simulate the deposition path. The deposition path and the deposition parameters obtained in step 101 are introduced into the plasma arc fuse additive manufacturing equipment; Step 103, fix the substrate on the 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; 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 head of the plasma arc welding gun, and coaxially introduce argon gas with a flow rate of 15L / min to 30L / min as a shielding gas into the plasma arc welding gun; 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; 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: The deposition parameters 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.

3. The plasma arc fuse additive manufacturing method of a high-performance rare earth magnesium alloy according to claim 1, 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.

4. The plasma arc fuse additive manufacturing method of a high-performance rare earth magnesium alloy according to claim 1, characterized in that: The thickness of the ZM6 magnesium alloy plate in step 101 is 10 mm to 30 mm.

5. The plasma arc fuse additive manufacturing method of a high-performance rare earth magnesium alloy according to claim 1, characterized in that: In step 103, the preheating temperature of the substrate is 150°C to 250°C.

6. The plasma arc fuse additive manufacturing method of a high-performance rare earth magnesium alloy according to claim 1, characterized in that: The deposition process described in step 2 is: when the target ZM6 magnesium alloy workpiece is a prism, the wall thickness is less than 10 mm, and a single-pass or double-pass reciprocating straight line or curved path is used for direct deposition until the first deposition layer is obtained; when the wall thickness is greater than 10 mm and it is impossible to directly deposit by a single pass or a double pass, firstly deposit according to a "bow"-shaped reciprocating straight line or curved path to complete the deposition of the entire surface inside the first layer, and 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, and the deposition thickness of the outer contour is higher than that of the inner part; When the target ZM6 magnesium alloy workpiece is an impeller, arc deposition is first performed on the inner ring of the impeller. After 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 to obtain the first deposition layer, and then layer by layer deposition is performed in the same manner to obtain the formed part.

7. The plasma arc fuse additive manufacturing method of a high-performance rare earth magnesium alloy according to claim 6, characterized in that: After the deposition molten pool of each deposition layer solidifies, a grinding and polishing machine is immediately used to grind the surface of the deposition layer.

8. The plasma arc fuse additive manufacturing method of a high-performance rare earth magnesium alloy according to claim 6, characterized in that: The path of each deposition layer of the formed part is 0° to 90° with respect to the adjacent deposition layer.

Images