CN116618792A - Arc additive manufacturing method of Mg-Y-Nd-Zr rare earth magnesium alloy structural member - Google Patents

Abstract

The invention provides an arc additive manufacturing method of a Mg-Y-Nd-Zr rare earth magnesium alloy structural member, which takes wires with Mg-Y-Nd-Zr as main alloy elements as raw materials, adopts a CMT arc additive technology, and prints layer by layer in an upward growth mode from a first layer on a substrate according to a preset program until the last layer is printed, so as to obtain a printed piece; when each layer of printing is carried out, a double arc is adopted, a substrate or a previous layer of deposition body is preheated by a TIG arc, and a CMT material adding arc is processed in a material adding mode on the preheated substrate or the previous layer of deposition body, so that simultaneous preheating and material adding are realized, and the mechanical property and the surface quality of a formed component are improved; and (3) transferring the printing piece to a heat treatment furnace by adopting an insulation box, and performing heat treatment after the printing piece is insulated for a period of time to obtain the required Mg-Y-Nd-Zr rare earth magnesium alloy structural member. The method of the invention improves the mechanical property and the surface quality of the formed member and improves the material increasing efficiency.

Description

Arc Additive Manufacturing Method for Mg-Y-Nd-Zr Rare Earth Magnesium Alloy Structural Parts

technical field

The invention relates to the technical field of arc additive manufacturing, in particular to an arc additive manufacturing method for Mg-Y-Nd-Zr rare earth magnesium alloy structural parts.

Background technique

Mg-Y-Nd-Zr (WE series) rare earth magnesium alloy has the characteristics of high temperature resistance and high strength. After the addition of rare earth elements, the high-temperature mechanical properties and high-temperature performance of the alloy are significantly improved, and are widely used in aerospace fields, such as new aero-engine gearboxes and helicopter transmission systems, and gradually replace some structural medium-strength aluminum alloys. In addition, the rare earth magnesium alloy has a high ignition point, and can be widely used in coal mines, natural gas and components that are in contact with easily combustible substances.

At present, the main manufacturing method of rare earth magnesium alloy structural parts is casting, but it is more difficult to cast complex structural parts, the shrinkage of magnesium alloy is large when solidified, and there will be defects such as shrinkage porosity, shrinkage cavity and oxidation inside the casting.

Arc additive manufacturing has the advantages of flexible forming process, high material utilization rate, low cost, and excellent mechanical properties of stacked bodies. It is especially suitable for manufacturing complex structural parts. However, due to the high thermal conductivity and fast heat dissipation of magnesium alloys, when the first layer of arc is added, the heat generated by the arc will quickly conduct through the substrate and be further lost in the air. The liquid metal molten pool has a small range, shallow depth, and unstable shape, which leads to unstable bonding between the metal of the first layer of additives and the substrate, resulting in pore defects, and at the same time, the stress of the subsequent additive body will gradually accumulate to the bonding site , so that cracking occurs, and in severe cases, the deposit and the substrate cannot be combined. At present, the most commonly used solution is to preheat the substrate. The current methods of preheating the substrate by arc additives are mainly contact heating, induction heating, and in-situ heating.

Contact heating requires the use of asbestos electric blankets in contact with the substrate and the deposition body, and heat conduction occurs between the two for heating. However, this method has low heat transfer efficiency, takes a long time, and consumes a lot of energy. In addition, the structure of the deposition body is complex and the area When heating between layers, using contact heating will require more asbestos electric blankets to ensure that the surface to be heated can be fully covered, which means that the area of the asbestos electric blanket that does not contact the deposition body increases rapidly, making More heat is lost to the air, wasting energy.

In the induction heating method, since the magnesium alloy is not ferromagnetic, compared with the ferromagnetic material, the induction heating efficiency of the magnesium alloy is lower, usually between 45% and 60%, so the induction heating consumes a lot of energy and takes a long time.

In-situ heating uses an additive arc to add 1-2 layers of material on the substrate to increase the temperature of the substrate. The essence is that the addition of materials on the substrate will change the surface shape of the substrate and affect the transition layer between the deposit and the substrate. Defects will occur in the transition layer. At the same time, the 1-2 layers of metal used for in-situ heating will cause waste. In addition, in-situ heating is only suitable for heating the substrate and cannot be used to heat the deposited body.

Contents of the invention

The purpose of the present invention is to address the deficiencies in the prior art, to provide an arc additive manufacturing method for Mg-Y-Nd-Zr rare earth magnesium alloy structural parts, using Mg-Y-Nd-Zr rare earth magnesium alloy wire as the filling material, Double arcs are used, TIG arc is preheated in front, and CMT additive arc is used to add material after processing, so as to improve the mechanical properties and surface quality of formed components and improve the efficiency of material addition.

The invention relates to an arc additive manufacturing method for a Mg-Y-Nd-Zr rare earth magnesium alloy structural part, comprising the following steps:

Using Mg-Y-Nd-Zr wire as the main alloying element as the raw material, the CMT arc additive process is used to print layer by layer from the first layer on the substrate in the way of upward growth according to the preset program until it reaches the The last layer, to get the print;

Among them, when printing each layer, double arcs are used, and the TIG arc is used to preheat the substrate or the previous layer of deposition. The CMT additive arc is used to preheat the substrate or the previous layer of deposition. The process is carried out by adding materials on the surface, so as to realize preheating and material addition at the same time, and improve the mechanical properties and surface quality of the formed components;

An incubator is used to keep the printed parts warm and transfer them to a heat treatment furnace. After a period of time, heat treatment is carried out to obtain the required Mg-Y-Nd-Zr rare earth magnesium alloy structural parts.

As an optional embodiment, the components of the wire include: 4.8-5.5% Y, 4.0-4.5% Nd, 0.4-0.5% Zr, Gd≤0.01%, Zn≤0.015%, Fe≤0.015%, Mn≤0.015%, the rest is Mg.

As an optional embodiment, the AC TIG welding arc is used to preheat the substrate or the previous deposited layer, the diameter of the tungsten electrode is 2mm, the welding current is 40-80A, the welding speed is 500-2000mm/min, the preheating temperature of the substrate The temperature is 135-150°C, and the preheating temperature of the deposition body of the previous layer is 120-130°C.

As an optional implementation, in the CMT arc additive process, the dry elongation is 13-16mm, and it is set to determine the arc additive speed, wire feeding speed and welding current according to the parameters of the rare earth magnesium alloy workpiece.

As an optional embodiment, the arc additive speed is 0.02-0.03 m/s, the wire feeding speed is 5.5-6.0 m/min, and the welding current is 140-150A.

As an optional embodiment, in the arc additive process, a mixed gas of argon and helium is used as the protective gas, wherein the volume ratio of the gas is: argon 60-70%, helium 30-40%.

As an optional embodiment, the temperature in the incubator is 90-110°C.

As an optional implementation manner, after the printed part enters the heat treatment furnace, it is kept at a temperature of 120-150° C. for 10-12 hours.

As an optional implementation, heat treatment is performed on the printed part after heat preservation, including solution treatment and aging treatment.

As an optional embodiment, the solution treatment is: heat preservation at a temperature of 520° C. to 525° C. for 6 to 8 hours; the aging treatment is: heat preservation at a temperature of 240° C. to 250° C. for 16 hours to 20 hours.

Compared with prior art, remarkable beneficial effect of the present invention is:

The arc additive manufacturing method of Mg-Y-Nd-Zr rare earth magnesium alloy structural parts of the present invention uses Mg-Y-Nd-Zr rare earth magnesium alloy wire as the filling material, adopts double electric arcs, and preheats with TIG electric arcs , at the same time, the CMT additive arc is processed by adding materials later. When the TIG arc is heated, no molten pool is formed on the surface of the substrate, and the flatness of the substrate surface will not be changed, so that it will not affect the transition between the deposit and the substrate. layer, to avoid defects in the transition layer, and because the TIG arc adopts the AC welding mode, it has a cathodic cleaning effect, which can clean the oxide film on the surface of the magnesium alloy, reduce the intrusion of the magnesium alloy oxide during the material addition process, and reduce the defects in the deposit Occurrence, improve the mechanical properties and surface quality of formed components.

The arc additive manufacturing method of Mg-Y-Nd-Zr rare earth magnesium alloy structural parts of the present invention adopts TIG electric arc as heat source to carry out preheating, makes reciprocating motion by TIG electric arc, utilizes electric arc heat to gradually heat, and the heat transfer efficiency of electric arc heating High, improve the efficiency of material addition, and the TIG arc can fully act on the deposition body, and there will be no situation where the heat source is heated to output heat but the deposition body cannot absorb it.

Description of drawings

Fig. 1 is a process flow chart of the arc additive manufacturing method of the Mg-Y-Nd-Zr rare earth magnesium alloy structural part of the present invention.

Fig. 2 is a schematic diagram of the dual path of preheating and deposition in an exemplary embodiment of the present invention.

Fig. 3 is a structural schematic diagram of an exemplary printed matter transfer incubator of the present invention.

Fig. 4 is a physical diagram of the rare earth magnesium alloy structural part obtained in Example 1 of the present invention.

5 is a cross-sectional view of the rare earth magnesium alloy structural part obtained in Example 1 of the present invention; wherein, part a is the sample in the deposited state, and part b is the sample after heat treatment.

Fig. 6 is a microstructure diagram of the rare earth magnesium alloy structural part obtained in Example 1 of the present invention; wherein, part a is the sample in the deposited state, and part b is the sample after heat treatment.

Fig. 7 is the actual picture of the sample obtained in Comparative Example 1 of the present invention.

Fig. 8 is an actual picture of the sample obtained in Comparative Example 2 of the present invention.

Detailed ways

In order to better understand the technical content of the present invention, specific embodiments are given together with the attached drawings for description as follows.

Aspects of the invention are described in this disclosure with reference to the accompanying drawings, which show a number of illustrated embodiments. Embodiments of the present disclosure are not necessarily intended to include all aspects of the invention. It should be appreciated that the various concepts and embodiments introduced above, as well as those concepts and implementations described in more detail below, can be implemented in any of numerous ways.

In conjunction with the flow chart shown in Figure 1, the exemplary arc additive manufacturing method of Mg-Y-Nd-Zr rare earth magnesium alloy structural parts of the present invention includes the following steps:

Using Mg-Y-Nd-Zr wire as the main alloying element as the raw material, the CMT arc additive process is used to print layer by layer from the first layer on the substrate in the way of upward growth according to the preset program until it reaches the The last layer, to get the print;

Among them, when printing each layer, double arcs are used, and the TIG arc is used to preheat the substrate or the previous layer of deposition. The CMT additive arc is used to preheat the substrate or the previous layer of deposition. The process is carried out by adding materials on the surface, so as to realize preheating and material addition at the same time, and improve the mechanical properties and surface quality of the formed components;

An incubator is used to keep the printed parts warm and transfer them to a heat treatment furnace. After a period of time, heat treatment is carried out to obtain the required Mg-Y-Nd-Zr rare earth magnesium alloy structural parts.

As an optional embodiment, the components of the wire include: 4.8-5.5% Y, 4.0-4.5% Nd, 0.4-0.5% Zr, Gd≤0.01%, Zn≤0.015%, Fe≤0.015%, Mn≤0.015%, the rest is Mg.

At present, the arc additive manufacturing of rare earth magnesium alloys mainly uses Mg-Gd-Y series magnesium alloys. The main alloying elements are Gd and Y, which can improve the performance of rare earth magnesium alloys to a certain extent, but the cost of adding Gd elements is high. Mg-Y-Nd-Zr (WE series) magnesium alloy has lower cost and wider application range.

As an optional embodiment, the AC TIG welding arc is used to preheat the substrate or the previous deposited layer, the diameter of the tungsten electrode is 2mm, the welding current is 40-80A, the welding speed is 500-2000mm/min, the preheating temperature of the substrate The temperature is 135-150°C, and the preheating temperature of the deposition body of the previous layer is 120-130°C.

As an optional implementation, in the CMT arc additive process, the dry elongation is 13-16mm, and it is set to determine the arc additive speed, wire feeding speed and welding current according to the parameters of the rare earth magnesium alloy workpiece.

As an optional embodiment, the arc additive speed is 0.02-0.03 m/s, the wire feeding speed is 5.5-6.0 m/min, and the welding current is 140-150A.

As an optional embodiment, in the arc additive process, a mixed gas of argon and helium is used as the protective gas, wherein the volume ratio of the gas is: argon 60-70%, helium 30-40%.

As an optional embodiment, the temperature in the incubator is 90-110°C.

As an optional implementation manner, after the printed part enters the heat treatment furnace, it is kept at a temperature of 120-150° C. for 10-12 hours.

As an optional implementation, heat treatment is performed on the printed part after heat preservation, including solution treatment and aging treatment.

As an optional embodiment, the solution treatment is: heat preservation at a temperature of 520° C. to 525° C. for 6 to 8 hours; the aging treatment is: heat preservation at a temperature of 240° C. to 250° C. for 16 hours to 20 hours.

In one of the typical embodiments, an arc additive manufacturing method for a Mg-Y-Nd-Zr rare earth magnesium alloy structure is provided, including the following specific steps:

S1. According to the material composition requirements of the structural parts, select the corresponding wire material, in which the main rare earth element content should meet the requirements, the diameter of the wire material is 1.2mm ~ 1.6mm, and the packaging is required to be good, and there are no obvious oxides and impurities on the surface;

Main material composition (mass fraction): Y 4.8～5.5%, Nd 4.0～4.5%, Zr0.4～0.5%, Gd≤0.01%, Zn≤0.015%, Fe≤0.015%, Mn≤0.015%, the rest is Mg .

The substrate for deposition is preferably WE54.

S2. Preprocess the 3D model of the target structural part to generate an additive model, and use the additive processing software to perform layered slicing, and the layered height is 2-3mm;

Plan the deposition path for each layer of slices. The path is preferably serpentine reciprocating, with a reciprocating distance of 1.5-3mm. At the same time, the paths of adjacent slices need to be misaligned, and the misalignment distance is 1-1.5mm;

In the path planning of each layer slice, the arc starting point and arc extinguishing point of the arc should not coincide with the previous layer, and the distance should be greater than 20mm, otherwise local collapse will occur, and the planned path program should be imported into the robot control system;

Plan the TIG arc heating path, the heating path is in the same direction as the additive path, and the waveform is different.

Preferably, the interlayer heating path (that is, heating the deposition body) adopts a sinusoidal waveform, which is different from the rectangular waveform of the additive deposition path, and the waveform width and spacing value of the heating path are the same as the deposition path, wherein the width of the additive sample is Waveform width, the spacing value is the serpentine reciprocating spacing in the deposition path, as shown in Figure 2;

And realize that the TIG arc is in the front, and the additive arc is in the back. The substrate or the previous layer of deposition is heated by the TIG arc. When the heating temperature reaches the requirement, the CMT additive arc starts to work, and the two arcs move and work at the same time, which can realize the same There are two paths in the layer slice to realize two kinds of arc front and back work.

S3. Fix the substrate on the workbench, clean it with ultrasonic waves, and then wipe it with acetone and air-dry it.

S4. Preheat after cleaning. The preheating method is to use TIG arc to heat the substrate. Robot A controls the TIG arc to heat the substrate according to the planned heating path. The preheating temperature is controlled at 135-150°C, and the TIG arc needs to be controlled. The welding current and speed of movement ensure that the surface of the substrate does not melt.

The AC TIG welding arc is preferred, the diameter of the tungsten electrode is 2mm, the welding current is 40-80A, and the welding speed is 500-2000mm/min.

S5. When the temperature reaches the standard, robot B controls the additive arc to run according to the deposition path to realize the deposition of each layer of metal.

Among them, the protective gas used is preferably mixed gas, the volume ratio is: argon 60-70%, helium 30-40%, gas flow 20-24L/min;

CMT welding mode is adopted, the dry elongation is 13-16mm, the arc additive speed is 0.02-0.03m/s, the wire feeding speed is 5.5-6.0m/min, and the welding current is 140-150A.

S6. After the addition of each layer, the interlayer temperature needs to be controlled. The TIG arc starts to work according to the interlayer heating path, and the robot A carries the TIG arc to move along the deposition path. After the temperature reaches the standard, the robot B starts the arc addition;

Before each layer is added, the temperature sensor is used to measure the temperature. It is necessary to ensure that the interlayer temperature is 120-130 ° C, and the welding current and moving speed of the TIG arc need to be controlled to ensure that the surface of the substrate does not melt.

The AC TIG welding arc is preferred, the diameter of the tungsten electrode is 2mm, the welding current is 40-80A, and the welding speed is 500-2000mm/min.

The previous layer of deposition is heated by the TIG arc. When the heating temperature reaches the requirement, the additive arc starts to work, and the two arcs move and work at the same time. It can realize two paths in the same layer of slices, and realize two arcs working before and after;

TIG arc heating, additive arc deposition, proceed layer by layer, and finally complete the manufacture of rare earth magnesium alloy structural parts.

S7. After the addition of structural parts, use the sample transfer incubator in time to transfer the deposited body to the heat treatment furnace for heat preservation, and the temperature in the box is required to be 100°C;

In a preferred embodiment, as shown in Figure 3, the structure of the sample transfer incubator is: a box body 1 and a box door 2 connected with the box body, a metal shell is provided around the box body 1, and the inside of the box body 1 The cavity is provided with an asbestos layer 11, and a resistance heating wire 12 and a temperature sensor 13 are provided on the inner wall of the box.

The box body is powered by a built-in lithium battery power supply 3, and the box body is also provided with a temperature controller 4 and a temperature indicator 5 inside the box.

The working principle is: using lithium battery power supply, the resistance heating wire generates heat, the temperature inside the box rises, the asbestos layer can prevent the heat from being dissipated, and improve the insulation performance of the box. When the temperature reaches the required temperature, stop heating, because the box will Heat radiation outward, the temperature inside the box is lower than the required temperature, the power is turned on, and the resistance heating wire continues to work, so that the temperature inside the box can meet the requirement.

In the conventional arc additive, the sample is directly transported to the heat treatment furnace without using a transfer incubator. This process takes a long time, which will cool the deposited sample, and cracks will occur at the joint between the substrate and the deposited body. The invention transfers the sample to the incubator in time after the material addition is completed, and controls the ambient temperature of the sample. At the same time, the incubator itself carries a lithium battery power supply, which can be moved together with the transportation tool without external power cords, which is convenient and fast.

S8. After the sample enters the heat treatment furnace, heat preservation first, heat preservation setting: temperature 120 ~ 150 ℃, heat preservation time 10 ~ 12h;

Start heat treatment within 2 hours after the end of heat preservation. The heat treatment plan includes solution treatment and aging treatment. Solution treatment is 520℃～525℃ and heat preservation is 6～8h, aging treatment is 240℃～250℃ and heat preservation is 16h～20h. within ℃.

In order to facilitate a better understanding, the present invention will be further described below in conjunction with specific examples, but the processing technology is not limited thereto, and the content of the present invention is not limited thereto.

Example 1

1. According to the material composition requirements of structural parts, select the corresponding wire material. The wire material composition is: 4.3% Nd, 5.0% Y, 0.41% Zr, 0.006% Gd, 0.012% Zn, 0.015% Fe, 0.015% Mn, and the rest is Mg .

The diameter of the wire is 1.2mm, and it is required to be well packaged without obvious oxides and impurities on the surface. The deposition substrate is WE54.

2. Preprocess the 3D model of the target structure, and use Solidworks software to generate an additive model.

Use R-CAM additive processing software to perform layered slices. The layered height is 2mm. The deposition path of each slice is serpentine reciprocating, and the reciprocating distance is 1.5mm. At the same time, the paths of adjacent slices need to be misaligned. In the path planning of layer slices, the arc starting point and arc extinguishing point of the arc should not coincide with the previous layer, and the distance should be greater than 20mm;

Plan the TIG arc heating path, the heating path adopts a sinusoidal waveform, and the waveform spacing is 1.5mm, and the TIG arc is in front, and the additive arc is behind;

Import the planned path into the robot control system.

3. Fix the substrate on the workbench, clean it with ultrasonic waves, and then wipe it with acetone and air-dry it.

4. Preheat after cleaning. The preheating method is to use TIG arc to heat the substrate. The robot A controls the movement of the TIG welding torch on the substrate to continuously heat the plate. The preheating temperature is controlled to be 135-150°C. , the diameter of the tungsten pole is 2mm, the welding current is 50A, and the welding speed is 1200mm/min.

5. After the preheating temperature reaches the requirement, robot B controls the additive arc to run according to the deposition path to realize the metal deposition of each layer;

Process parameters include: the use of protective gas as a mixed gas, argon 70%, helium 30%, gas flow 24L/min;

The welding mode is CMT, the dry elongation is 13mm, the arc additive speed is 0.02m/s, the wire feeding speed is 5.6m/min, and the welding current is 140A.

6. After the addition of each layer, the interlayer temperature needs to be controlled. The TIG arc starts to work according to the interlayer heating path. The interlayer heating path adopts a sinusoidal waveform, and the waveform spacing is based on 1.5mm. It is adjusted according to the actual shape of each layer. Robot A carries the TIG arc to move along the heating path. After the temperature reaches the standard, robot B starts to add materials by arc. Before adding materials on each layer, use a temperature sensor to measure the temperature. It is necessary to ensure that the temperature between layers is 120-130°C;

The TIG arc heats the previous layer of deposited body. When the heating temperature reaches the requirement, the additive arc starts to work, and the two arcs move and work at the same time. It can realize two paths in the same layer slice, and realize two kinds of arcs working before and after; TIG Arc heating, additive arc deposition, layer by layer, and finally complete the manufacture of rare earth magnesium alloy structural parts;

7. After the addition of structural parts, use the sample transfer incubator in time to transfer the deposited body to the heat treatment furnace for heat preservation. The temperature in the box is required to be 100 °C.

8. In the heat treatment furnace, heat preservation setting: temperature 130°C, heat preservation time 12h; start heat treatment within 2h after heat preservation, heat treatment plan includes solution treatment and aging treatment, solution treatment 525°C heat preservation 8h, aging treatment 240°C heat preservation 18h, the furnace temperature is required to be controlled within ±4°C.

Comparative example 1

The difference from Example 1 is that the substrate and the previous layer of deposited body are not preheated, and the material addition is directly performed.

Comparative example 2

Using steps 1 to 6 in Example 1, a rare earth magnesium alloy printed part was obtained and cooled to room temperature.

appearance

By the Mg-Y-Nd-Zr rare earth magnesium alloy deposition sample obtained in this embodiment (as shown in Figure 4), the deposition sample is taken off from the substrate, and the bottom of the sample (joint with the sample), the top The 10mm part of the deposit was removed, and the remaining part was sampled by wire cutting. After cutting, inlaying, rough grinding, fine grinding, polishing and corrosion, the cross-sectional shape and microstructure of the deposited body were observed. The results are shown in Figure 5 and Figure 6.

In Figure 5a, it can be found that there are pores inside the deposited metal, which mainly occur near the junction line of the serpentine reciprocating track and track, and a small amount occur in the inner area of the single track. Using a high-power optical microscope, the results in Figure 6a are obtained. It can be seen that the pores mainly occur in Metal grain boundaries.

It can be seen from Figure 6b that after heat treatment, the eutectic structure at the grain boundary is dissolved, and the distribution of continuous strips is transformed into short rods and dots, and the segregation of Cu elements is improved, and the pores disappear at the same time. After appropriate heat treatment temperature and time After that, it can be seen that all the pores on the cross section of the deposit disappear, as shown in Figure 5b. At the same time, according to Fig. 5a, it can be seen that there is no air hole near the bonding line between the layers. It can be seen that the TIG arc used in the present invention has a good effect on heating the interlayer metal.

Figure 7 shows the sample of Comparative Example 1. The substrate was not preheated. It can be seen that when the substrate is not preheated, the substrate does not melt in the first layer of arc addition, because the arc heat is conducted by the substrate, and the remaining heat is not enough to melt the substrate. , there is no liquid molten pool on the substrate, as a result, the deposits and the substrate cannot be combined, and the deposits are completely separated from the substrate after being subjected to the stress of the deposits.

If the sample fails to be heat-preserved in time after the arc addition is completed, but waits for the sample to cool before performing heat treatment, it will be found that the sample cracks after cooling before heat treatment, as shown in the comparative example in Figure 8 2 samples. This is because when the sample is rapidly cooled, the internal stress generated by continuous deposition will be released quickly, and it will appear at the stress concentration point on the structure, that is, cracking will occur. There is stress concentration near the joint between the deposition sample and the substrate, so transverse cracks occur between the first, second, and third layers of the deposited metal of the sample, crossing the cross-section of the deposition body.

From the above tests, it can be seen that the surface of the rare earth magnesium alloy structural part obtained by the method of the present invention is well formed, and after preheating by TIG electric arc, the interlayer bonding of the deposit body is good, especially the bond between the deposit body and the substrate is good, and no crack defect is found. The molten pool on the substrate is deep enough to form a good bond with the first layer of deposited metal. At the same time, timely heat preservation measures are adopted after the arc addition is completed, so that the internal stress of the deposit will not be released suddenly and cause cracks, and the stress will be gradually released during the heat treatment stage without affecting the deposit. In addition, there will be tiny pores in the deposited body, if not treated, the mechanical properties will be affected. Using a reasonable heat treatment process can eliminate the internal pores and improve the performance of the sample.

Mechanical property test

According to "GB/T 228.1-2010 Metal Materials Tensile Test Part 1: Room Temperature Test Method", take a tensile sample on the deposited sample and perform room temperature stretching. Compare the tensile test results with the mechanical property requirements of similar composition materials in ISO3116:2007(E).

It can be seen from the test results that the tensile strength and yield strength of the Mg-Y-Nd-Zr rare earth magnesium alloy deposition sample after heat treatment are higher than the requirements of ISO3116, in which the tensile strength is increased by about 12%, and the yield strength is increased by about 30%. %, the main reason for the increase in strength is the dissolution of supersaturated solid solution, the precipitation of strengthening phases, solid solution strengthening and precipitation strengthening are the main strengthening methods for increasing strength. This mechanical property structure meets the design requirements of Mg-Y-Nd-Zr rare earth magnesium alloy castings, so it can be It can be used instead of rare earth magnesium alloy castings.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Those skilled in the art of the present invention may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be defined by the claims.

Claims (10)

1. an electric arc additive manufacturing method of a Mg-Y-Nd-Zr rare earth magnesium alloy structure, is characterized in that, comprises the following steps: Using Mg-Y-Nd-Zr wire as the main alloying element as the raw material, the CMT arc additive process is used to print layer by layer from the first layer on the substrate in the way of upward growth according to the preset program until it reaches the The last layer, to get the print; Among them, when printing each layer, double arcs are used, and the TIG arc is used to preheat the substrate or the previous layer of deposition. The CMT additive arc is used to preheat the substrate or the previous layer of deposition. The process is carried out by adding materials on the surface, so as to realize preheating and material addition at the same time, and improve the mechanical properties and surface quality of the formed components; An incubator is used to keep the printed parts warm and transfer them to a heat treatment furnace. After a period of time, heat treatment is carried out to obtain the required Mg-Y-Nd-Zr rare earth magnesium alloy structural parts. 2. The arc additive manufacturing method of Mg-Y-Nd-Zr rare earth magnesium alloy structural parts according to claim 1, characterized in that the composition of the wire comprises: 4.8 to 5.5% Y, Nd 4.0 ～4.5%, Zr 0.4～0.5%, Gd≤0.01%, Zn≤0.015%, Fe≤0.015%, Mn≤0.015%, and the rest is Mg. 3. the arc additive manufacturing method of Mg-Y-Nd-Zr rare earth magnesium alloy structural part according to claim 1, is characterized in that, adopts the preheating of substrate or previous layer deposition layer by AC TIG welding arc, tungsten The pole diameter is 2mm, the welding current is 40-80A, the welding speed is 500-2000mm/min, the preheating temperature of the substrate is 135-150°C, and the preheating temperature of the previous layer of deposited body is 120-130°C. 4. The arc additive manufacturing method of Mg-Y-Nd-Zr rare earth magnesium alloy structural parts according to claim 1, characterized in that, in the CMT arc additive process, the dry elongation is 13-16mm, and is It is set to determine the arc additive speed, wire feeding speed and welding current according to the rare earth magnesium alloy workpiece parameters. 5. The arc additive manufacturing method of Mg-Y-Nd-Zr rare earth magnesium alloy structural parts according to claim 1, characterized in that, the arc additive speed is 0.02～0.03m/s, and the wire feeding speed is 5.5~6.0m/min, welding current 140~150A. 6. The arc additive manufacturing method of the Mg-Y-Nd-Zr rare earth magnesium alloy structure according to claim 1, characterized in that, in the arc additive process, a mixed gas of argon and helium is used as the shielding gas , wherein, the volume ratio of gas is: 60-70% of argon gas, and 30-40% of helium gas. 7. The arc additive manufacturing method for Mg-Y-Nd-Zr rare earth magnesium alloy structural parts according to claim 1, characterized in that the temperature in the incubator is 90-110°C. 8. The arc additive manufacturing method of Mg-Y-Nd-Zr rare earth magnesium alloy structural parts according to claim 1, characterized in that, after the printed parts enter the heat treatment furnace, they are kept at a temperature of 120-150°C for 10-10°C. 12h. 9. The arc additive manufacturing method of Mg-Y-Nd-Zr rare earth magnesium alloy structural parts according to claim 1, characterized in that heat treatment is performed on the printed parts after heat preservation, including solution treatment and aging treatment. 10. The arc additive manufacturing method of Mg-Y-Nd-Zr rare earth magnesium alloy structural parts according to claim 9, characterized in that the solution treatment is: heat preservation at a temperature of 520° C. to 525° C. for 6 to 8 hours; The aging treatment is: heat preservation at 240°C-250°C for 16h-20h.