Magnesium alloy electric arc additive component and manufacturing method and application thereof

Abstract

The invention provides a magnesium alloy electric arc additive component and a manufacturing method and application thereof, and belongs to the technical field of electric arc additive manufacturing. The manufacturing method of the magnesium alloy electric arc additive component comprises the following steps that a magnesium alloy base plate is fixed to a printing table, a magnesium alloy wire is conveyed to the position below a welding gun, single-channel layer-by-layer reciprocating welding is carried out, after welding of each layer is completed, an oxidation film on the surface of a printed piece is cleaned, and after the interlayer temperature reaches 80-100 DEG C, welding of the next layer is carried out; and the steps are repeated to the target height, and the magnesium alloy electric arc additive component is obtained. According to the manufacturing method of the magnesium alloy electric arc additive component, control over internal defects of the magnesium alloy and good interlayer combination can be achieved, the obtained magnesium alloy electric arc additive component is small in mechanical property anisotropy, and the strength and plasticity are remarkably improved.

Description

Technical Field

[0001] The present invention relates to arc additive manufacturing technology, and in particular to a magnesium alloy arc additive component, a manufacturing method and use thereof. Background Art

[0002] Magnesium alloy is the lightest structural metal material in existing engineering applications, with a density of only 1.7-1.8 g / cm 3 , which is 1 / 4 of steel, 1 / 3 of titanium and 2 / 3 of aluminum. It also has the advantages of high specific strength, large elastic modulus, fast heat dissipation, good shock absorption and strong electromagnetic shielding, and has broad application prospects in the fields of automobiles, rail transportation, aerospace and medical care. However, due to the limitations of traditional casting, such as complex process flow, low material utilization, high manufacturing cost, porosity and macro segregation, and poor mechanical properties, this greatly increases the manufacturing cost of magnesium alloy components and limits the application of magnesium alloys.

[0003] Cold Metal Transfer (CMT) arc additive technology uses the arc as the heat source, plans the forming path according to the solid model of the part, drives the welding gun through the wire feeding system under the displacement equipment such as the robotic arm, and gradually forms from bottom to top according to the planned path. Compared with the traditional casting process, arc additive manufacturing technology has the advantages of high precision, fast cooling rate, and high material utilization rate. However, since arc additive forming is prepared by stacking components layer by layer, oxidation will occur between layers during the additive process and will be contaminated by factors such as spatter and burning, resulting in more defects between the layers of the component, uneven tissue distribution, and poor performance. In addition, the temperature difference between the upper and lower layers of the component causes differences in the organization and performance of the component along the stacking direction.

[0004] In existing research, Wang Huiyuan et al. disclosed an arc additive manufacturing method for magnesium alloy wire (see Chinese Patent 202211454753.0). The conditions for printing magnesium alloy wire are: welding current of 70-250A, welding voltage of 10-25V, and 150s between each layer under pure argon protection. Although the process proposes to stay for 150s after arc extinguishing in each layer of welding, the strength and plasticity of the material obtained are relatively low. The tensile strength and elongation of the printed AZ31B magnesium alloy are only 213.4MPa and 13.2%, which cannot meet the more stringent use environment.

[0005] Therefore, in order to improve the performance of arc additively manufactured magnesium alloy components, reduce internal defects, and enhance the stability of organization and performance along the stacking direction, it is of great practical significance to develop a layer-by-layer controlled CMT arc additively manufactured magnesium alloy. Summary of the invention

[0006] The purpose of the present invention is to propose a method for manufacturing magnesium alloy arc additive components in view of the problems that the existing methods for manufacturing magnesium alloy components by arc additive manufacturing have many interlayer defects, uneven tissue distribution and poor performance. The method can achieve control of internal defects in magnesium alloys and good interlayer bonding. The magnesium alloy arc additive components thus obtained have low anisotropy of mechanical properties, and both strength and plasticity are significantly improved.

[0007] It should be noted that, in the present invention, unless otherwise specified, the specific meaning of "including" in relation to composition limitations and descriptions includes both open-ended "including", "comprising", etc. and similar meanings, as well as closed-ended "composed of", "composed of", etc. and similar meanings.

[0008] To achieve the above object, the technical solution adopted by the present invention is: a method for manufacturing a magnesium alloy arc additive component, comprising the following steps:

[0009] The magnesium alloy substrate is fixed on the printing table, and the magnesium alloy wire is sent under the welding gun for single-pass reciprocating welding layer by layer. After each layer of welding, the oxide film on the surface of the printed part is cleaned and the interlayer temperature is waited to reach 80-100°C before welding the next layer. This process is repeated to the target height to obtain a magnesium alloy arc additive component. The interlayer temperature is measured in real time using a temperature measuring gun.

[0010] Furthermore, single-pass layer-by-layer reciprocating welding is performed with the length direction of the magnesium alloy substrate as the printing direction.

[0011] Furthermore, the magnesium alloy substrate is a Mg-Al-Zn alloy substrate.

[0012] Furthermore, the magnesium alloy wire is a Mg-Al-Zn alloy wire.

[0013] Furthermore, the Mg—Al—Zn alloy wire includes at least one of AZ91D magnesium alloy wire and AZ31B magnesium alloy wire.

[0014] Furthermore, the diameter of the Mg-Al-Zn alloy wire is 0.8-1.6 mm.

[0015] Furthermore, before the single-pass layer-by-layer reciprocating welding, the magnesium alloy substrate is polished and preheated in sequence; the preheating temperature is 80-100°C.

[0016] Furthermore, a heating plate is provided between the magnesium alloy substrate and the printing table, a thermocouple is provided on the heating plate, and the thermocouple is connected to a temperature control box to control the temperature of the heating plate, thereby achieving constant temperature heating of the magnesium alloy substrate. Furthermore, the heating plate is a cast aluminum heating plate.

[0017] Furthermore, before the first layer of welding is performed, the heating plate is turned on to heat the magnesium alloy substrate at a constant temperature.

[0018] Furthermore, the welding speed of the single-pass layer-by-layer reciprocating welding is 0.2-1.0 m / min.

[0019] Furthermore, the welding current of the single-pass layer-by-layer reciprocating welding is 115-145A, and the welding voltage is 11.0-13.0V.

[0020] Furthermore, the single-pass layer-by-layer reciprocating welding is performed in an atmosphere of a protective gas; the protective gas is argon gas; and the gas flow rate of the protective gas is 15 to 20 L / min.

[0021] Furthermore, the single-layer height of the single-pass reciprocating welding is 2.5-3.5 mm.

[0022] Another object of the present invention is to provide a magnesium alloy arc additive component prepared by the above method.

[0023] Furthermore, the magnesium alloy arc additive component is an AZ91D magnesium alloy component or an AZ31B magnesium alloy component.

[0024] Furthermore, the tensile strength of the AZ91D magnesium alloy component is 264-275 MPa, and the elongation is 13.8-16.3%.

[0025] Furthermore, the tensile strength of the AZ31B magnesium alloy component is 242-246 MPa, and the elongation is 22.9-28.6%.

[0026] Another object of the present invention is to disclose a magnesium alloy arc additive component for use in the automotive, rail transportation, aerospace and medical fields.

[0027] The magnesium alloy arc additive component, the manufacturing method and the use thereof of the present invention have the following advantages compared with the prior art:

[0028] 1) The present invention achieves good bonding between layers of the magnesium alloy arc additive component by controlling the interlayer surface quality and interlayer temperature during the additive process layer by layer, thereby ensuring the structural uniformity and mechanical property stability of the obtained magnesium alloy arc additive component along the deposition direction and improving the overall strength.

[0029] 2) The manufacturing method provided by the present invention can achieve the control of internal defects of magnesium alloy and good bonding between layers. The magnesium alloy arc additive component obtained thereby has small anisotropy of mechanical properties, and both strength and plasticity are significantly improved. It also has the advantages of high precision, fast cooling rate and small grain size.

[0030] 3) The present invention effectively improves the problems of grain growth caused by high heat input and untimely heat dissipation in the arc additive manufacturing process, easy formation of pores in the additive manufacturing process, etc. by adjusting the printing parameters including welding current, welding voltage and welding speed, thereby achieving the coordinated improvement of the strength and plasticity of Mg-Al-Zn alloys in arc additive manufacturing.

[0031] 4) The present invention heats the magnesium alloy substrate at a constant temperature by means of a heating plate, thereby reducing the rapid diffusion of the temperature of the magnesium alloy melt within the solidification range, effectively solving the problem of excessive interlayer thickness and a large number of pore defects caused by insufficient melt fluidity during the additive process, and improving the interlayer bonding strength and forming quality of the magnesium alloy component. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a physical picture of the AZ91D magnesium alloy component manufactured by CMT arc additive manufacturing obtained in Example 1;

[0033] Figure 2 This is an optical micrograph of the CMT arc additively manufactured AZ91D magnesium alloy component obtained in Example 3;

[0034] Figure 3 Schematic diagram of sampling along different orientations of the CMT arc additively manufactured AZ91D magnesium alloy component obtained in Example 3 (left figure) and its stress-strain tensile curve (right figure). DETAILED DESCRIPTION

[0035] The present invention is further described below with reference to the examples. The description of the technical features described below is based on representative embodiments and specific examples of the present invention, but the present invention is not limited to these embodiments and specific examples. It should be noted that:

[0036] Unless otherwise stated, the units used in this specification are all international standard units, and the numerical values ​​and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0037] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints numerical values ​​A and B.

[0038] In this specification, the numerical range expressed using "above" or "below" means a numerical range including the number.

[0039] In this specification, the word "may" includes both performing a certain process and not performing a certain process.

[0040] In this specification, the use of "optional" or "optional" indicates that certain substances, components, execution steps, application conditions and other factors are used or not used.

[0041] In this specification, when "normal temperature" or "room temperature" is used, the temperature may be 15-25°C.

[0042] In this manual, the reagents or instruments used without indicating the manufacturer are all conventional products that can be obtained through commercial purchase.

[0043] The present invention provides a method for manufacturing a magnesium alloy arc additive component, comprising the following steps:

[0044] The magnesium alloy substrate is fixed on the printing table, and the magnesium alloy wire is sent under the welding gun. The length direction of the magnesium alloy substrate is used as the printing direction for single-pass reciprocating welding layer by layer. After each welding, the oxide film on the surface of the printed part is cleaned and the next layer of welding is performed again after the interlayer temperature reaches 80-100°C. This process is repeated until the target height is reached to obtain a magnesium alloy arc additive component.

[0045] In the present invention, unless otherwise specified, the raw materials used are commercially available products well known to those skilled in the art or are prepared by methods well known to those skilled in the art.

[0046] The present invention fixes a magnesium alloy substrate on a printing table, feeds a magnesium alloy wire under a welding gun, and performs single-pass reciprocating welding layer by layer with the length direction of the magnesium alloy substrate as the printing direction. After each welding, the oxide film on the surface of the printed part is cleaned and the next layer of welding is performed again after the interlayer temperature reaches 80-100°C. This process is repeated until the target height is reached to obtain a magnesium alloy arc additive component.

[0047] In the present invention, the magnesium alloy wire is preferably a Mg-Al-Zn alloy wire. In the present invention, the Mg-Al-Zn alloy wire preferably includes at least one of AZ91D magnesium alloy wire and AZ31B magnesium alloy wire, and is more preferably AZ91D magnesium alloy wire or AZ31B magnesium alloy wire. The alloy composition of the AZ91D magnesium alloy wire of the present invention is preferably Mg-8.7Al-0.5Zn-0.2Mn; the alloy composition of the AZ31B magnesium alloy wire is preferably Mg-3.0Al-0.7Zn-0.4Mn. The diameter of the Mg-Al-Zn alloy wire of the present invention is preferably 0.8 to 1.6 mm, and more preferably 1.0 to 1.2 mm.

[0048] The present invention preferably loads magnesium alloy wire into the wire feeding device, feeds the magnesium alloy wire to 5-10 mm below the welding gun, and corrects the position of the wire feeding device so that the magnesium alloy wire faces the printing table.

[0049] In the present invention, the magnesium alloy substrate is preferably a Mg-Al-Zn alloy substrate. In the present invention, the single-pass layer-by-layer reciprocating welding preferably includes grinding and preheating the magnesium alloy substrate in sequence. The present invention preferably uses an angle grinder to grind and remove the oxide layer on the surface of the magnesium alloy substrate. The preheating temperature of the present invention is preferably 80 to 100°C, specifically 80°C, 90°C or 100°C.

[0050] After the magnesium alloy substrate is preheated, the present invention preferably performs single-pass layer-by-layer reciprocating welding according to preset procedures and parameters. The present invention preferably controls the robot arm through the program, thereby controlling the motion trajectory of the welding gun; the parameters preferably include at least one of the welding speed, welding current and welding voltage. In the present invention, the welding speed is preferably 0.2-1.0 m / min, more preferably 0.5 m / min; the welding current is preferably 115-145 A, specifically 115 A, 120 A, 130 A, 140 A or 145 A; the welding voltage is preferably 11.0-13.0 V, specifically 11.3 V, 11.7 V, 12 V, 12.4 V or 12.7 V. In the present invention, the operation steps of the single-pass reciprocating welding preferably include: starting an arc on one side of the magnesium alloy substrate, extinguishing the arc after welding one layer in the length direction, raising the welding gun to a certain height by controlling the robot arm, cleaning the oxide film on the surface of the printed part and waiting for the interlayer temperature to reach the preset temperature before starting the arc again, continuing the second welding in the opposite direction of the first welding, and reciprocating to the target height. The single-pass reciprocating welding of the present invention is preferably carried out in an atmosphere of protective gas; the protective gas is preferably argon gas; the gas flow rate of the protective gas is preferably 15 to 20 L / min, specifically 15 L / min, 16 L / min, 17 L / min, 18 L / min, 19 L / min or 20 L / min. In the present invention, when performing interlayer cleaning, the oxide layer on the surface of the scanned part and the spatter, burning and other pollution generated during the single-pass reciprocating welding process must be polished off. The preset temperature of the present invention is preferably 80 to 100 ° C, specifically 80 ° C, 90 ° C or 100 ° C. In the present invention, the single layer height of the single-pass reciprocating welding is preferably 2.5-3.5 mm, specifically 2.7 mm, 2.8 mm, 2.95 mm, 2.98 mm or 3.25 mm.

[0051] The present invention also provides a magnesium alloy arc additive component prepared by the manufacturing method described in the above technical solution.

[0052] In the present invention, the magnesium alloy arc additive component preferably includes an AZ91D magnesium alloy component or an AZ31B magnesium alloy component. The tensile strength of the AZ91D magnesium alloy component of the present invention is preferably 264-275MPa, and the elongation is preferably 13.8-16.3%; the tensile strength of the AZ91D magnesium alloy component in the printing direction is preferably 273-275MPa, and the elongation is preferably 14.1-16.3%; the tensile strength in the stacking direction is preferably 264-271MPa; and the elongation is preferably 13.8-14.8%. The tensile strength of the AZ31B magnesium alloy component of the present invention is preferably 242-246 MPa, and the elongation is preferably 22.9-28.6%; the tensile strength of the AZ31B magnesium alloy component in the printing direction is preferably 244-245 MPa, and the elongation is preferably 25.9-28.6%; the tensile strength in the stacking direction is preferably 242-246 MPa; and the elongation is preferably 22.9-24.9%.

[0053] Example 1

[0054] In this embodiment, AZ91D magnesium alloy wire (alloy composition: Mg-8.7Al-0.5Zn-0.2Mn) with a diameter of 1.2 mm is used for CMT arc additive manufacturing to control stacking layer by layer to print straight wall-shaped components. The preparation method includes the following steps:

[0055] (1) Load AZ91D magnesium alloy wire into the wire feeding device, feed the wire to 5 mm below the welding gun, and correct its position so that the magnesium alloy wire faces the printing table;

[0056] (2) Using an angle grinder to remove the oxide layer on the surface of the magnesium alloy substrate, fixing the magnesium alloy substrate on a printing table and preheating the magnesium alloy substrate to 100° C.;

[0057] (3) After the magnesium alloy substrate is preheated, a single-pass multi-layer process is used for additive manufacturing according to a preset procedure under argon protection. The operating parameters during the additive manufacturing process are as follows: the welding current is 115A, the welding voltage is 11.3V, the welding speed is 0.5m / min, the argon gas flow rate is 20L / min, the length direction of the magnesium alloy substrate is the welding gun running direction, the direction perpendicular to the magnesium alloy substrate is the component stacking direction, the welding gun starts arc welding from one side of the substrate, and after welding one layer along the length direction of the magnesium alloy substrate, the arc is stopped and welding is stopped, and the welding gun is raised;

[0058] (4) Use a steel wire brush to grind the upper surface oxide film of the weld, as well as the spatter and burns generated during the additive manufacturing process, and measure the temperature in real time. After the temperature drops to 100°C, lower the welding gun to 3 mm above the previous layer, start the arc again, and weld in the opposite direction of the previous welding. Repeat this process. The surface quality and interlayer temperature need to be controlled between each layer. After welding 22 layers, a CMT arc additively manufactured AZ91D magnesium alloy straight wall (hereinafter referred to as a magnesium alloy arc additive component) is obtained. The magnesium alloy arc additive component is about 130 mm long, 8.1 mm wide, and 64.9 mm high, and each layer is about 2.95 mm high.

[0059] No pores or cracks were observed during the welding process of the magnesium alloy arc additive component prepared in this embodiment. The actual picture of the magnesium alloy arc additive component is as follows: Figure 1 As shown. Figure 1 It can be seen that there are no obvious defects on the surface of the magnesium alloy arc additive component after grinding, the difference in welding width of each layer is small, the bonding state between layers is good, and there is no obvious stratification phenomenon on the macro scale.

[0060] Tensile sheets were taken from the magnesium alloy arc additive component obtained in this embodiment along the printing direction and the stacking direction. The tensile strength and elongation of the magnesium alloy arc additive component obtained in this embodiment along the printing direction and the stacking direction were tested using the method disclosed in the national standard GB / T228-2002. The tensile strength in the printing direction (TD) was 273MPa and the elongation was 14.1%; the tensile strength in the stacking direction (BD) was 271MPa and the elongation was 13.8%. It can be seen that the magnesium alloy arc additive component obtained by the present invention has high strength and plasticity, uniform tissue distribution, stable mechanical properties, good interlayer bonding, and effectively improves the mechanical properties of the AZ91D alloy.

[0061] Example 2

[0062] In this embodiment, AZ91D magnesium alloy wire (alloy composition: Mg-8.7Al-0.5Zn-0.2Mn) with a diameter of 1.2 mm is used for CMT arc additive manufacturing to control stacking layer by layer to print straight wall-shaped components. The preparation method includes the following steps:

[0063] (1) Load AZ91D magnesium alloy wire into the wire feeding device, feed the wire to 5 mm below the welding gun, and correct its position so that the magnesium alloy wire faces the printing table;

[0064] (2) Using an angle grinder to remove the oxide layer on the surface of the magnesium alloy substrate, fixing the magnesium alloy substrate on a printing table and preheating the magnesium alloy substrate to 100° C.;

[0065] (3) After the magnesium alloy substrate is preheated, the additive manufacturing is performed using a single-pass multi-layer process according to a preset procedure under the condition of argon protection. The operating parameters during the additive manufacturing process are as follows: the welding current is 130A, the welding voltage is 12V, the welding speed is 0.5m / min, the argon gas flow rate is 20L / min, the length direction of the magnesium alloy substrate is the welding gun running direction, the direction perpendicular to the magnesium alloy substrate is the component stacking direction, the welding gun starts arc welding from one side of the substrate, and after welding one layer along the length direction of the magnesium alloy substrate, the arc is stopped and welding is stopped, and the welding gun is raised;

[0066] (4) Use a steel wire brush to grind the upper surface oxide film of the weld, as well as the spatter and burns generated during the additive manufacturing process, and measure the temperature in real time. After the temperature drops to 100°C, lower the welding gun to 3 mm above the previous layer, start the arc again, and weld in the opposite direction of the previous welding. Repeat this process. The surface quality and interlayer temperature need to be controlled between each layer. After welding 22 layers, a CMT arc additively manufactured AZ91D magnesium alloy straight wall (hereinafter referred to as a magnesium alloy arc additive component) is obtained. The magnesium alloy arc additive component is about 130 mm long, 8 mm wide, and 65.6 mm high, and each layer is about 2.98 mm high.

[0067] No pores or cracks were observed in the magnesium alloy arc additive component prepared in this embodiment during the welding process. The surface of the magnesium alloy arc additive component had no obvious defects after grinding, the difference in welding width of each layer was small, the interlayer bonding state was good, and there was no obvious stratification phenomenon on the macro scale.

[0068] Tensile sheets were taken from the magnesium alloy arc additive component obtained in this embodiment along the printing direction and the stacking direction. The tensile strength and elongation of the magnesium alloy arc additive component obtained in this embodiment along the printing direction and the stacking direction were tested using the method disclosed in the national standard GB / T228-2002. The tensile strength in the printing direction (TD) was 275MPa and the elongation was 16.1%; the tensile strength in the stacking direction (BD) was 264MPa and the elongation was 14.8%. It can be seen that the magnesium alloy arc additive component obtained by the present invention has high strength and plasticity, uniform tissue distribution, stable mechanical properties, good interlayer bonding, and effectively improves the mechanical properties of the AZ91D alloy.

[0069] Example 3

[0070] In this embodiment, AZ91D magnesium alloy wire (alloy composition: Mg-8.7Al-0.5Zn-0.2Mn) with a diameter of 1.2 mm is used for CMT arc additive manufacturing to control stacking layer by layer to print straight wall-shaped components. The preparation method includes the following steps:

[0071] (1) Load AZ91D magnesium alloy wire into the wire feeding device, feed the magnesium alloy wire to 5 mm below the welding gun, and correct its position so that the magnesium alloy wire faces the printing table;

[0072] (2) Using an angle grinder to remove the oxide layer on the surface of the magnesium alloy substrate, fixing the magnesium alloy substrate on a printing table and preheating the magnesium alloy substrate to 100° C.;

[0073] (3) After the magnesium alloy substrate is preheated, the additive manufacturing is performed using a single-pass multi-layer process according to a preset procedure under the condition of argon protection. The operating parameters during the additive manufacturing process are as follows: the welding current is 145A, the welding voltage is 12.7V, the welding speed is 0.5m / min, the argon gas flow rate is 20L / min, the welding gun is running in the length direction of the magnesium alloy substrate, and the component stacking direction is in the direction perpendicular to the magnesium alloy substrate. The welding gun starts arc welding from one side of the substrate, and after welding one layer along the length direction of the magnesium alloy substrate, the arc is stopped and welding is stopped, and the welding gun is raised;

[0074] (4) Use a steel wire brush to grind the upper surface oxide film of the weld, as well as the spatter and burns generated during the additive manufacturing process, and measure the temperature in real time. After the temperature drops to 100°C, lower the welding gun to 3 mm above the previous layer, start the arc again, and weld in the opposite direction of the previous welding. Repeat this process. The surface quality and interlayer temperature need to be controlled between each layer. After welding 20 layers, a CMT arc additively manufactured AZ91D magnesium alloy straight wall (hereinafter referred to as a magnesium alloy arc additive component) is obtained. The magnesium alloy arc additive component is about 130 mm long, 7.9 mm wide, and 65 mm high, and each layer is about 3.25 mm high.

[0075] No pores or cracks were observed in the magnesium alloy arc additive component prepared in this embodiment during the welding process. The surface of the magnesium alloy arc additive component had no obvious defects after grinding, the difference in welding width of each layer was small, the interlayer bonding state was good, and there was no obvious stratification phenomenon on the macro scale.

[0076] Tensile sheets were taken from the magnesium alloy arc additive component obtained in this embodiment along the printing direction and the stacking direction. The tensile strength and elongation of the magnesium alloy arc additive component obtained in this embodiment along the printing direction and the stacking direction were tested using the method disclosed in the national standard GB / T228-2002. The tensile strength in the printing direction (TD) was 273MPa and the elongation was 16.3%; the tensile strength in the stacking direction (BD) was 265MPa and the elongation was 14.2%. It can be seen that the magnesium alloy arc additive component obtained by the present invention has high strength and plasticity, uniform tissue distribution, stable mechanical properties, good interlayer bonding, and effectively improves the mechanical properties of the AZ91D alloy.

[0077] Figure 2This is an optical micrograph of the CMT arc additively manufactured AZ91D magnesium alloy component obtained in Example 3. It can be observed that the grain size of the printed CMT arc additively manufactured AZ91D magnesium alloy component is small, only 20 to 30 μm.

[0078] Figure 3 This is a schematic diagram of sampling along different orientations of the CMT arc additively manufactured AZ91D magnesium alloy component obtained in Example 3 and its stress-strain tensile curve. It can be observed that the printed CMT arc additively manufactured AZ91D magnesium alloy component has high mechanical properties, and the difference along the welding (TD) and stacking (BD) directions is small. The tensile strength in the printing direction is 273 MPa, and the elongation is 16.3%. The tensile strength in the stacking direction is 265 MPa, and the elongation is 14.2%.

[0079] Example 4

[0080] In this embodiment, AZ31B magnesium alloy wire (alloy composition: Mg-3.0Al-0.7Zn-0.4Mn) with a diameter of 1.2 mm is used for CMT arc additive manufacturing to control stacking layer by layer to print straight wall-shaped components. The preparation method includes the following steps:

[0081] (1) Load AZ31B magnesium alloy wire into the wire feeding device, feed the magnesium alloy wire to 5 mm below the welding gun, and correct its position so that the magnesium alloy wire faces the printing table;

[0082] (2) Using an angle grinder to remove the oxide layer on the surface of the magnesium alloy substrate, fix the magnesium alloy substrate on the printer and preheat the magnesium alloy substrate to 100°C;

[0083] (3) After the magnesium alloy substrate is preheated, the additive manufacturing is performed using a single-pass multi-layer process according to a preset procedure under the condition of argon protection. The operating parameters during the additive manufacturing process are as follows: the welding current is 120A, the welding voltage is 11.7V, the welding speed is 0.5m / min, the argon gas flow rate is 20L / min, the welding gun is running in the length direction of the magnesium alloy substrate, and the component stacking direction is in the direction perpendicular to the magnesium alloy substrate. The welding gun starts arc welding from one side of the substrate, and after welding one layer along the length direction of the magnesium alloy substrate, the arc is stopped and welding is stopped, and the welding gun is raised;

[0084] (4) Use a steel wire brush to grind the upper surface oxide film of the weld, as well as the spatter and burns generated during the additive manufacturing process, and measure the temperature in real time. After the temperature drops to 100°C, lower the welding gun to 3 mm above the previous layer, start the arc again, and weld in the opposite direction of the previous welding. Repeat this process. The surface quality and interlayer temperature need to be controlled between each layer. After welding 31 layers, a CMT arc additively manufactured AZ31B magnesium alloy straight wall (hereinafter referred to as a magnesium alloy arc additive component) is obtained. The magnesium alloy arc additive component is about 120 mm long, 7.9 mm wide, and 86 mm high, and each layer is about 2.8 mm high.

[0085] No pores or cracks were observed in the magnesium alloy arc additive component prepared in this embodiment during the welding process. The surface of the magnesium alloy arc additive component had no obvious defects after grinding, the difference in welding width of each layer was small, the interlayer bonding state was good, and there was no obvious stratification phenomenon on the macro scale.

[0086] Tensile sheets were taken from the magnesium alloy arc additive component obtained in this embodiment along the printing direction and the stacking direction. The tensile strength and elongation of the magnesium alloy arc additive component obtained in this embodiment along the printing direction and the stacking direction were tested using the method disclosed in the national standard GB / T228-2002. The tensile strength in the printing direction (TD) was 244MPa and the elongation was 28.6%; the tensile strength in the stacking direction (BD) was 242MPa and the elongation was 24.9%. It can be seen that the magnesium alloy arc additive component obtained by the present invention has high strength and plasticity, uniform tissue distribution, stable mechanical properties, good interlayer bonding, and effectively improves the mechanical properties of AZ31B magnesium alloy.

[0087] Example 5

[0088] In this embodiment, AZ31B magnesium alloy wire (alloy composition: Mg-3.0Al-0.7Zn-0.4Mn) with a diameter of 1.2 mm is used for CMT arc additive manufacturing to control stacking layer by layer to print straight wall-shaped components. The preparation method includes the following steps:

[0089] (1) Load AZ31B magnesium alloy wire into the wire feeding device, feed the magnesium alloy wire to 5 mm below the welding gun, and correct its position so that the magnesium alloy wire faces the printing table;

[0090] (2) Using an angle grinder to remove the oxide layer on the surface of the magnesium alloy substrate, fixing the magnesium alloy substrate on a printing table and preheating the magnesium alloy substrate to 100° C.;

[0091] (3) After the magnesium alloy substrate is preheated, a single-pass multi-layer process is used for additive manufacturing under argon protection according to a preset procedure. The operating parameters during the additive manufacturing process are as follows: the welding current is 140A, the welding voltage is 12.4V, the welding speed is 0.5m / min, the argon gas flow rate is 20L / min, the length direction of the magnesium alloy substrate is the welding gun running direction, the direction perpendicular to the magnesium alloy substrate is the component stacking direction, the welding gun starts arc welding from one side of the substrate, and after welding one layer along the length direction of the magnesium alloy substrate, the arc is stopped and welding is stopped, and the welding gun is raised;

[0092] (4) Use a steel wire brush to grind the upper surface oxide film of the weld, as well as the spatter and burns generated during the additive manufacturing process, and measure the temperature in real time. After the temperature drops to 100°C, lower the welding gun to 3 mm above the previous layer, start the arc again, and weld in the opposite direction of the previous welding. Repeat this process. The surface quality and interlayer temperature need to be controlled between each layer. After welding 31 layers, a CMT arc additively manufactured AZ31B magnesium alloy straight wall (hereinafter referred to as a magnesium alloy arc additive component) is obtained. The magnesium alloy arc additive component is about 120 mm long, 8.0 mm wide, and 85 mm high, and each layer is about 2.7 mm high.

[0093] No pores or cracks were observed in the magnesium alloy arc additive component prepared in this embodiment during the welding process. The surface of the magnesium alloy arc additive component had no obvious defects after grinding, the difference in welding width of each layer was small, the interlayer bonding state was good, and there was no obvious stratification phenomenon on the macro scale.

[0094] Tensile sheets were taken from the magnesium alloy arc additive component obtained in this embodiment along the printing direction and the stacking direction. The tensile strength and elongation of the magnesium alloy arc additive component obtained in this embodiment along the printing direction and the stacking direction were tested using the method disclosed in the national standard GB / T228-2002. The tensile strength in the printing direction (TD) was 245MPa and the elongation was 25.9%; the tensile strength in the stacking direction (BD) was 246MPa and the elongation was 22.9%. It can be seen that the magnesium alloy arc additive component obtained by the present invention has high strength and plasticity, uniform tissue distribution, stable mechanical properties, good interlayer bonding, and effectively improves the mechanical properties of AZ31B magnesium alloy.

[0095] Comparative Example 1

[0096] Wang Dianjun et al. provided the properties of cast AZ91 magnesium alloy, with a tensile strength of 117 MPa and an elongation of 1.4% (see Wang Dianjun, Hu Maoliang, Zhang Mingqiu, et al. Effect of carbon powder addition on microstructure and mechanical properties of AZ91 magnesium alloy [J]. Hot Working Technology, 2024, 53(3): 135-139+144).

[0097] Comparing Examples 1, 2, and 3 with Comparative Example 1, it is found that the mechanical properties of the AZ91D magnesium alloy components obtained by additive manufacturing of the present invention are significantly improved compared to the cast AZ91D magnesium alloy components. Compared with Comparative Example 1, the tensile strength of the CMT arc additively manufactured magnesium alloy components obtained in Examples 1, 2, and 3 along the printing direction are increased by 156MPa, 158MPa, and 156MPa, respectively, and the elongation is increased by 13.2%, 14.7%, and 14.9%, respectively; the tensile strength along the stacking direction is increased by 191MPa, 184MPa, and 185MPa, respectively, and the elongation is increased by 12.4%, 13.4%, and 12.8%, respectively.

[0098] Comparative Example 2

[0099] Wang Huiyuan et al. used AZ31 magnesium alloy wire with a diameter of 1.2 mm to print straight-walled magnesium alloy components. The operating parameters of additive manufacturing in Example 1 were: welding current of 80 A, welding voltage of 12 V, but the welding gun was only raised 2.5 mm and stayed for 60 seconds after each layer of arc extinguishing, without considering the control of interlayer surface quality, interlayer temperature and other factors. The tensile strength and elongation of the obtained metal straight-walled components were tested using the method disclosed in the national standard GB / T228-2002, with a tensile strength of 213.4 MPa and an elongation of 13.2% (see patent 202211454753.0).

[0100] Comparing Examples 4 and 5 with Comparative Example 2, it is found that the mechanical properties of additively manufactured AZ31B magnesium alloy components can be effectively improved by controlling the interlayer temperature and surface quality layer by layer during additive manufacturing. Compared with Comparative Example 2, the tensile strength of Examples 4 and 5 along the printing direction is increased by 30.6MPa and 31.6MPa, respectively, and the elongation is increased by 15.4% and 12.7%, respectively; the tensile strength along the stacking direction is increased by 28.6MPa and 32.6MPa, respectively, and the elongation is increased by 11.7% and 9.7%, respectively.

[0101] In summary, the present invention significantly improves the strength and plasticity of Mg-Al-Zn magnesium alloys produced by arc additive manufacturing by controlling the interlayer temperature and surface quality layer by layer during the additive manufacturing process. The process is simple and low-cost, and can meet a wider range of application needs.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for manufacturing a magnesium alloy arc additive component, characterized in that: The following steps are involved: The magnesium alloy substrate is fixed on the printing table, and the magnesium alloy wire is sent under the welding gun for single-pass reciprocating welding layer by layer. After each layer of welding, the oxide film on the surface of the printed part is cleaned and the interlayer temperature is waited to reach 80-100°C before welding the next layer. This process is repeated until the target height is reached to obtain a magnesium alloy arc additive component.

2. The method for manufacturing a magnesium alloy arc additive component according to claim 1, characterized in that: The magnesium alloy substrate is a Mg-Al-Zn alloy substrate; And / or, the magnesium alloy wire is a Mg-Al-Zn alloy wire; And / or, the diameter of the Mg-Al-Zn alloy wire is 0.8-1.6 mm.

3. The method for manufacturing a magnesium alloy arc additive component according to claim 1, characterized in that: The single-pass layer-by-layer reciprocating welding includes grinding and preheating the magnesium alloy substrate in sequence; the preheating temperature is 80-100°C.

4. The method for manufacturing a magnesium alloy arc additive component according to claim 3, characterized in that: A heating plate is arranged between the magnesium alloy substrate and the printing table, a thermocouple is arranged on the heating plate, and the thermocouple is connected to a temperature control box to control the temperature of the heating plate, thereby achieving constant temperature heating of the magnesium alloy substrate.

5. The method for manufacturing a magnesium alloy arc additive component according to claim 1, characterized in that: The welding speed of the single-pass layer-by-layer reciprocating welding is 0.2-1.0 m / min; And / or, the welding current of the single-pass layer-by-layer reciprocating welding is 115-145A, and the welding voltage is 11.0-13.0V.

6. The method for manufacturing a magnesium alloy arc additive component according to claim 1, characterized in that: The single-pass layer-by-layer reciprocating welding is performed in an atmosphere of protective gas; the protective gas is argon gas; and the gas flow rate of the protective gas is 15 to 20 L / min.

7. The method for manufacturing a magnesium alloy arc additive component according to claim 1, characterized in that: The single-layer height of the single-pass reciprocating welding is 2.5-3.5 mm.

8. A magnesium alloy arc additive component, characterized in that: The method is prepared by any one of claims 1 to 7.

9. The magnesium alloy arc additive component according to claim 8, characterized in that: The magnesium alloy arc additive component is an AZ91D magnesium alloy component or an AZ31B magnesium alloy component.

10. Use of the magnesium alloy arc additive component according to claim 8 or 9 in the fields of automobiles, rail transportation, aerospace and medical treatment.

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