Aluminum-magnesium gradient layered metal composite material and preparation method thereof

Abstract

The invention belongs to the field of materials, and discloses an aluminum-magnesium gradient layered metal composite material and a preparation method thereof.The preparation method comprises the following steps that an aluminum alloy wire is fed into an electric arc area of a welding system to be melted, and a first layer of aluminum is deposited on a base material; when the first layer of aluminum is not completely solidified, the magnesium alloy wire is fed into an electric arc area of a welding system to be melted, and a first layer of magnesium is deposited on the aluminum layer; and when the first layer of magnesium is not completely solidified, the aluminum alloy wire is fed into an electric arc area of a welding system to be melted, a second layer of aluminum is deposited on the magnesium layer, and the aluminum-magnesium gradient layered metal composite material is obtained. According to the prepared material, the interfacial strength between aluminum / magnesium layers is effectively improved, the common problems of layering and cracking in a traditional composite material synthesis method are solved, and meanwhile the effective weight reduction effect is achieved.

Description

Technical Field

[0001] The invention belongs to the field of materials and relates to an aluminum-magnesium gradient layered metal composite material and a preparation method thereof. Background Art

[0002] With the continuous development of modern industry, breakthroughs in materials science have played a vital role in promoting the progress of many manufacturing industries, especially in the fields of military industry and aerospace, where the demand for lightweight materials is becoming more and more urgent. In the military industry, the application of lightweight materials can reduce the weight of weapons and equipment, thereby improving the mobility of equipment, reducing equipment operating costs and enhancing the combat effectiveness of equipment; while in the aerospace field, the use of lightweight materials can reduce the weight of the aircraft itself, thereby enabling it to carry more payload and increase the range.

[0003] Aluminum, magnesium and their alloys are the most common lightweight metal materials in the manufacturing industry. Aluminum and aluminum-based alloys have good corrosion resistance and can maintain stable chemical properties in many complex environments, but compared with general lightweight metals, their density is higher (2.70g / cm 3 ), this defect limits the application of aluminum and aluminum-based alloys in fields with strict requirements for lightweight materials; magnesium and magnesium-based alloys have the advantage of light density (1.74g / cm 3 ), which can effectively reduce the weight of the product, thereby improving the energy efficiency of the product. However, the chemical properties of magnesium and magnesium-based alloys are very active, and chemical reactions are prone to cause corrosion damage, thus limiting their service life and reliability. If aluminum and magnesium can be combined into a new material in a suitable way, so that it can not only play the advantages of aluminum and magnesium, but also avoid the defects of both, it will significantly promote the military and aerospace fields to a higher level of development.

[0004] Traditional composite material synthesis methods, such as rolling and welding, have limitations in the practice of combining magnesium and aluminum. From the perspective of rolling, the difference in the physical properties of aluminum and magnesium leads to a loose interface between the two, which is prone to delamination and cracking. In addition, the rolling method has extremely high requirements for equipment and processes, and it is difficult to achieve complex shape forming. As for welding, the aluminum-magnesium composite material prepared by welding has stress concentration and uneven chemical composition at the aluminum / magnesium interface, which makes its interface strength low (<100MPa), which also leads to delamination and cracking. In addition, when producing composite materials, the traditional synthesis method is cumbersome, has low production efficiency, and it is difficult to ensure the consistency of product quality. Summary of the invention

[0005] The purpose of the present invention is to provide an aluminum-magnesium gradient layered metal composite material having excellent mechanical properties, corrosion resistance and formability and a manufacturing process thereof.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A method for preparing an aluminum-magnesium gradient layered metal composite material comprises the following steps:

[0008] Feeding aluminum alloy wire into the arc area of ​​the welding system to melt and deposit on the substrate to form the first layer of aluminum;

[0009] When the first layer of aluminum has not yet completely solidified, the magnesium alloy wire is fed into the arc area of ​​the welding system to melt and deposit on the aluminum layer to form the first layer of magnesium;

[0010] When the first layer of magnesium has not yet completely solidified, the aluminum alloy wire is fed into the arc area of ​​the welding system to melt and deposit on the magnesium layer to form a second layer of aluminum, thereby obtaining an aluminum-magnesium gradient layered metal composite material.

[0011] Furthermore, the method further comprises:

[0012] When the second layer of aluminum has not yet completely solidified, a magnesium alloy wire is fed into the arc area of ​​the welding system to melt and deposit on the aluminum layer to form a second layer of magnesium;

[0013] When the second layer of magnesium has not yet completely solidified, the magnesium alloy wire is fed into the arc area of ​​the welding system to melt, and is deposited on the magnesium layer to form a third layer of aluminum, thereby obtaining an aluminum-magnesium gradient layered metal composite material.

[0014] Furthermore, the thickness of each aluminum layer is 2-3 mm, and the thickness of each magnesium layer is 1-2 mm.

[0015] Furthermore, the diameter of the magnesium alloy wire is 1.2~1.6mm, and the diameter of the aluminum alloy wire is in the range of 1.6~2.0mm; the purity of magnesium in the magnesium alloy is greater than 99.8%, and the purity of aluminum in the aluminum alloy is greater than 99.9%.

[0016] Furthermore, the wire feeding speed of aluminum alloy wire is 4~6m / min; the wire feeding speed of magnesium alloy wire is 6-8m / min; and the wire feeding speed in the transition zone between aluminum / magnesium is 5~7m / min.

[0017] Furthermore, the welding power of the aluminum layer is 3.0~4.5 kW, and the pulse frequency is 50~100 Hz; the welding power of the magnesium layer is 2.5~3.5 kW, and the pulse frequency is 100~200 Hz; and hot and cold alternating pulses are used in the transition zone between aluminum and magnesium.

[0018] Furthermore, the welding speed is 0.3~0.8m / min; when depositing the aluminum layer, the temperature in the arc is 700~750℃; when depositing the magnesium layer, the temperature in the arc is about 660~680℃, and in the transition period between depositing the magnesium layer and depositing the aluminum layer, the temperature in the arc changes linearly between 660~750℃.

[0019] Furthermore, the substrate is made of aluminum alloy ER4043.

[0020] Furthermore, after depositing each metal layer, the substrate is rotated 90° clockwise, and the welding gun is moved in a direction perpendicular to the previous layer to form a wavy interlayer staggered structure.

[0021] The present invention also provides an aluminum-magnesium gradient layered metal composite material, which is prepared by the above-mentioned preparation method.

[0022] A method for preparing a three-layer aluminum-magnesium gradient layered metal composite material by arc additive manufacturing comprises the following steps:

[0023] (a) Prepare magnesium alloy wire and aluminum alloy wire. Ensure that the surfaces of the two materials are clean and free of oxides or other impurities. If necessary, surface treatment (such as grinding or chemical cleaning) can be performed.

[0024] (b) Use a six-axis robot welding system equipped with a double-wire feeding system, configure the welding power supply, and ensure that the shielding gas supply is sufficient and the airflow is stable during the preparation process. In addition, it is necessary to set the welding path, adjust the wire feeding speed and welding speed, and set the appropriate welding power and pulse mode.

[0025] (c) Deposition of the first layer of aluminum: The wire feeding system is started to feed the aluminum alloy wire into the arc area. The aluminum alloy wire is melted by the high temperature of the arc and deposited on the predetermined substrate to form a layer of aluminum with a thickness of 2.5 mm.

[0026] (d) Deposition of magnesium layer: When the first layer of aluminum has not yet completely solidified, switch the wire feeding system and rotate the substrate 90° clockwise to feed the magnesium alloy wire into the arc area. The high temperature of the arc is used to melt the magnesium alloy wire and deposit it on the aluminum layer to form a 1.5 mm thick magnesium layer.

[0027] (e) Deposition of the second layer of aluminum: When the magnesium layer has not yet completely solidified, the wire feeding system is switched again and the substrate is rotated 90° clockwise again to feed the aluminum alloy wire into the arc area, melt it and deposit it on the magnesium layer, forming a second layer of aluminum with a thickness of 2.5 mm.

[0028] (f) After deposition is completed, use a small current to fill the pit and ensure that the arc pit is filled to prevent the occurrence of shrinkage cracks. Turn off the welding power supply and shielding gas supply, and check whether the residual welding wire in the wire feeding system is clean.

[0029] In step (a) of the above technical solution, the diameter range of the magnesium alloy wire is determined to be 1.2-1.6 mm, and the diameter range of the aluminum alloy wire is determined to be 1.6-2.0 mm. The purity of magnesium in the magnesium alloy is required to be greater than 99.8%, and the purity of aluminum in the aluminum alloy is required to be greater than 99.9%.

[0030] In step (b) described in the above technical solution, the six-axis robot welding system equipped with a double-wire feeding system is provided by Fronius; the welding power source is a Fronius TransPulse Synergic 3200 CMT power source, and the shielding gas is argon, and its flow rate is controlled in the range of 15~25L / min.

[0031] For aluminum, due to its high thermal conductivity, the wire feeding speed of aluminum alloy wire can be set to 4~6m / min to avoid overheating of the molten pool; for magnesium, due to its high thermal expansion coefficient, its wire feeding speed is higher than that of aluminum, and the wire feeding speed of magnesium alloy wire can be set to 6-8m / min to compensate for evaporation loss; for the transition layer between aluminum / magnesium, dynamic wire feeding speed can be used for adjustment (for example, the speed can be gradually increased from 5m / min to 7m / min when feeding from aluminum to magnesium).

[0032] In terms of welding power, the welding power of the aluminum layer can be set to 3.0~4.5 kW, and its pulse frequency is 50~100 Hz; the welding power of the magnesium layer can be slightly lower, at 2.5~3.5 kW, and its pulse frequency is 100~200 Hz; alternating hot and cold pulses can be used in the transition zone between the two materials to reduce interface stress.

[0033] The welding speed range is set at 0.3~0.8m / min.

[0034] In steps (c) to (e) of the above technical solution, the material of the selected substrate is an aluminum alloy substrate ER4043.

[0035] Deposition path refer to the instruction manual Figure 1 When depositing the first layer of aluminum, the welding gun moves in a wave-like manner on the substrate along the horizontal direction; after the substrate is fully covered, the substrate is rotated 90° clockwise to start depositing the magnesium layer, and the welding gun moves in a wave-like manner on the substrate along a direction perpendicular to the previous welding direction until it is fully covered; then, the substrate is rotated 90° clockwise again to start depositing the second layer of aluminum, and the substrate moves in a wave-like manner on the substrate along the horizontal direction again.

[0036] When depositing the aluminum layer, the temperature in the arc is set at about 700~750℃; when depositing the magnesium layer, the temperature in the arc is set at about 660~680℃. In the transition period between depositing the magnesium layer and depositing the aluminum layer, the temperature changes linearly between 700~750℃ and 660~680℃.

[0037] In the above technical solution, the strength of the magnesium / aluminum interface of the obtained material is increased to above 100 MPa, and the weight is successfully reduced by about 8.21%.

[0038] The present invention also seeks to protect the aluminum-magnesium gradient layered metal composite material obtained by the above preparation method.

[0039] Another corresponding technical solution is a method for preparing a five-layer aluminum-magnesium gradient layered metal composite material by arc additive, comprising the following steps:

[0040] (a) Prepare magnesium alloy wire and aluminum alloy wire. Ensure that the surfaces of the two materials are clean and free of oxides or other impurities. If necessary, surface treatment (such as grinding or chemical cleaning) can be performed.

[0041] (b) Use a six-axis robot welding system equipped with a double-wire feeding system, configure the welding power supply, and ensure that the shielding gas supply is sufficient and the airflow is stable during the preparation process. In addition, it is necessary to set the welding path, adjust the wire feeding speed and welding speed, and set the appropriate welding power and pulse mode.

[0042] (c) Deposition of the first layer of aluminum: The wire feeding system is started to feed the aluminum alloy wire into the arc area. The aluminum alloy wire is melted by the high temperature of the arc and deposited on the predetermined substrate to form a layer of aluminum with a thickness of 2.5 mm.

[0043] (d) Deposition of the first layer of magnesium: When the first layer of aluminum has not yet solidified, the wire feeding system is switched and the substrate is rotated 90° clockwise to feed the magnesium alloy wire into the arc area. The high temperature of the arc is used to melt the magnesium alloy wire and deposit it on the aluminum layer to form a 1.5 mm thick magnesium layer.

[0044] (e) Deposition of the second layer of aluminum: When the first layer of magnesium has not yet solidified, the wire feeding system is switched again and the substrate is rotated 90° clockwise again to feed the aluminum alloy wire into the arc area, melt it and deposit it on the magnesium layer, forming a second layer of aluminum with a thickness of 2.5 mm.

[0045] (f) Deposition of the second layer of magnesium: When the second layer of aluminum has not yet solidified, the wire feeding system is switched again and the substrate is rotated 90° clockwise again to feed the magnesium alloy wire into the arc area. The high temperature of the arc is used to melt the magnesium alloy wire and deposit it on the aluminum layer to form a 1.5 mm thick magnesium layer.

[0046] (g) Deposition of the third layer of aluminum: When the second layer of magnesium has not yet solidified, the wire feeding system is switched again and the substrate is rotated 90° clockwise again to feed the aluminum alloy wire into the arc area, melt it and deposit it on the magnesium layer, forming the second layer of aluminum with a thickness of 2.5 mm.

[0047] (h) After deposition is completed, use a small current to fill the pit and ensure that the arc pit is filled to prevent the occurrence of shrinkage cracks. Turn off the welding power supply and shielding gas supply, and check whether the residual welding wire in the wire feeding system is clean.

[0048] In step (a) of the above technical solution, the diameter range of the magnesium alloy wire is determined to be 1.2-1.6 mm, and the diameter range of the aluminum alloy wire is determined to be 1.6-2.0 mm. The purity of the magnesium alloy is required to be greater than 99.8%, and the purity of the aluminum alloy is required to be greater than 99.9%.

[0049] In step (b) described in the above technical solution, the six-axis robot welding system equipped with a dual-wire feeding system is provided by Fronius; the welding power source is a Fronius TransPulse Synergic 3200 CMT power source, and the shielding gas is argon, and its flow rate is controlled within the range of 15-25L / min.

[0050] For aluminum, due to its high thermal conductivity, the wire feeding speed can be set to 4-6m / min to avoid overheating of the molten pool; for magnesium, due to its high thermal expansion coefficient, its wire feeding speed is higher than that of aluminum and can be set to 6-8m / min to compensate for evaporation losses; for the transition layer between aluminum / magnesium, dynamic wire feeding speed can be used for adjustment (for example, the speed can be gradually increased from 5m / min to 7m / min when feeding from aluminum to magnesium).

[0051] In terms of welding power, the welding power of the aluminum layer can be set to 3.0~4.5 kW, and its pulse frequency is 50~100 Hz; the welding power of the magnesium layer can be slightly lower, at 2.5~3.5 kW, and its pulse frequency is 100~200 Hz; alternating hot and cold pulses can be used in the transition zone between the two materials to reduce interface stress.

[0052] The welding speed range is set at 0.3~0.8m / min.

[0053] In steps (c) to (g) of the above technical solution, the material of the selected substrate is an aluminum alloy substrate ER4043.

[0054] Welding path refer to the instruction manual Figure 2 When depositing the first layer of aluminum, the welding gun moves in a wave-like manner on the substrate along the horizontal direction; after the substrate is fully covered, the substrate is rotated 90° clockwise to start depositing the magnesium layer. At this time, the welding gun moves in a wave-like manner on the substrate in a direction perpendicular to the previous welding direction until it is fully covered; finally, it is basically rotated 90° clockwise again to start depositing the second layer of aluminum. At this time, the substrate moves in a wave-like manner on the substrate along the horizontal direction again. The above steps are repeated in sequence until the third layer of aluminum is fully covered.

[0055] When depositing the aluminum layer, the temperature in the arc is set at about 700~750℃; when depositing the magnesium layer, the temperature in the arc is set at about 660~680℃. In the transition period between depositing the magnesium layer and depositing the aluminum layer, the temperature changes linearly between 700~750℃ and 660~680℃.

[0056] In the above technical solution, the strength of the magnesium / aluminum interface of the obtained material is increased to above 100 MPa, and the weight is successfully reduced by about 10.16%.

[0057] The present invention also seeks to protect the aluminum-magnesium gradient layered metal composite material obtained by the above preparation method.

[0058] Beneficial Effects

[0059] (1) The composite material obtained by the above method is prepared by arc additive manufacturing, and its weight can be reduced by 8% compared with the aluminum alloy material of the same volume. A good composition gradient transition zone is formed between the layers of the material, and the interface strength can reach 154MPa, which exceeds the interface strength of the composite material with the same structure prepared by direct hot pressing by 24MPa (an increase of 316.7%). This is because each time a new layer of material is laid, the previously laid thin film material layer has not yet been completely solidified, so there is sufficient atomic diffusion between the two layers of material to form an atomic diffusion layer with good bonding strength; in addition, the tensile strength of the composite material prepared by this method can reach 280~300MPa, which exceeds the composite material with the same structure prepared by direct hot pressing (230MPa). This is because not only the atomic diffusion layer is formed, but also the residual stress and anisotropy left over from the hot pressing and rolling process are avoided, and the uniformity of the organization is ensured;

[0060] (2) The outer layer of the aluminum-magnesium gradient layered metal composite material of the present invention has aluminum with good corrosion resistance, which can protect the inner layer of magnesium from corrosion. The inner layer of magnesium significantly reduces the overall weight of the composite material, thereby effectively reducing energy consumption.

[0061] (3) The second technical solution has a five-layer alternating aluminum-magnesium structure. Compared with the three-layer structure of the first technical solution, it is easier to achieve gradient stress dispersion and effectively reduces the occurrence of stress concentration, thus having higher tensile strength and elongation. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 It is the deposition path of technical solution 1.

[0063] Figure 2 It is the deposition path of technical solution 2.

[0064] Figure 3 It is the atomic diffusion layer between the aluminum layer and the magnesium layer. DETAILED DESCRIPTION

[0065] The present invention will be further described below in conjunction with the embodiments.

[0066] Example 1

[0067] A method for preparing a three-layer aluminum-magnesium gradient layered metal composite material by arc additive manufacturing comprises the following steps:

[0068] (a) Select magnesium alloy wire with a diameter range of 1.2-1.6 mm and a purity of >99.8% and aluminum alloy wire with a diameter range of 1.6-2.0 mm and a purity of >99.9%, and clean the surface oxides by mechanical grinding and chemical cleaning with 5% nitric acid solution;

[0069] (b) A six-axis robot system (equipped with a double-wire feeding system) provided by Fronius was prepared as an arc additive device, and a Fronius TransPulse Synergic 3200 CMT welding power source was used. The arc additive device was filled with argon as a shielding gas, and its flow rate was set to 20 L / min (fluctuation range ±5 L / min);

[0070] (c) The substrate is made of ER4043 aluminum alloy, which is preheated to 150°C to eliminate thermal stress, while the welding gun moves to the corner of the substrate.

[0071] (d) When depositing the first layer of aluminum, the wire feeding speed was set to 5 m / min, the welding power was set to 4.0 kW, the pulse frequency was set to 75 Hz, the molten pool temperature was controlled at 730 ± 20 °C, and the welding gun moved in a wavy trajectory with an amplitude of 5 mm and a wavelength of 15 mm in the horizontal direction;

[0072] (e) When the deposition of the first layer of aluminum transitions to the deposition of the first layer of magnesium, the magnesium wire is immediately switched, the wire feeding speed is rapidly increased from 5m / min to 7m / min, the welding power is rapidly reduced to 3.0kW, the pulse frequency is increased to 175Hz, and the molten pool temperature rapidly decreases linearly to 670±10℃ over time. At the same time, the substrate is rotated 90° clockwise, and the welding gun is moved to another corner of the substrate;

[0073] (f) When depositing the first layer of magnesium, the wire feeding speed was maintained at 7 m / min, the welding power was maintained at about 3.0 kW, the pulse frequency was 175 Hz, the molten pool temperature was controlled at 670 ± 10 °C, and the welding gun moved in a wavy trajectory with an amplitude of 5 mm and a wavelength of 15 mm in a direction perpendicular to the previous one;

[0074] (g) When the deposition of the first layer of magnesium transitioned to the deposition of the second layer of aluminum, aluminum wire was immediately switched to aluminum wire, the wire feeding speed was quickly restored from 7m / min to 5m / min, the welding power was quickly increased to 4.2kW, the pulse frequency was reduced to 80Hz, and the molten pool temperature rapidly increased linearly to 730±20℃ over time. At the same time, the substrate was rotated 90° clockwise again, and the welding gun was moved to another corner of the substrate;

[0075] (h) When depositing the second layer of aluminum, the wire feeding speed is maintained at 5 m / min, the welding power is maintained at about 4.2 kW, the pulse frequency is 80 Hz, the molten pool temperature is controlled at 730 ± 20 °C, and the welding gun again moves in a wavy trajectory with an amplitude of 5 mm and a wavelength of 15 mm in the horizontal direction;

[0076] (i) Use a small current (≤1.5kW) to fill the arc pit in the arc closure stage to prevent shrinkage cracks. Clean the residual welding wire after turning off the gas.

[0077] Comparative Example 1

[0078] A method for preparing a three-layer aluminum-magnesium gradient layered metal composite material by direct hot pressing comprises the following steps:

[0079] (a) Prepare a layer of 100 mm × 100 mm × 2.5 mm aluminum 1050 material as the substrate, a layer of 100 mm × 100 mm × 1.5 mm magnesium AZ31B material as the cover, and place a layer of solder between the substrate and the sample;

[0080] (b) Prepare a FLT-3000 hydraulic press, heat the press head to 460°C~480°C, and adjust the resistance voltage to maintain a constant temperature;

[0081] (c) Preheat a 120 mm × 120 mm × 120 mm steel anvil to 450°C and cool to 350°C, then place the sample plate and the cover plate on the steel anvil from bottom to top;

[0082] (d) After pressing the sample with a hot press for 30 s at a pressure of 30 MPa, the resistance power supply was cut off and the pressing continued for 30 s to ensure that the sample cooled below the eutectic point and the connection interface solidified before the pressure was released. During the hot pressing process, two thermocouples were used to monitor the temperature of the press head and the anvil.

[0083] (e) Then, a layer of 100 mm × 100 mm × 2.5 mm aluminum 1050 material is prepared as a cover plate, and the composite material after the first hot pressing is used as a substrate. The (a)-(e) process is repeated to obtain the final composite material.

[0084] The experimental test results show that the composite material obtained by the method of Example 1 is 8% lighter than the pure magnesium material of the same volume. The interface strength of the material can reach 154MPa, far exceeding the 24MPa of Comparative Example 1. This is because Example 1 adopts the arc additive method. Each time a new layer of material is laid, the previously laid thin film material layer has not yet been completely solidified. In this way, there is sufficient atomic diffusion between the two layers of material to form an atomic diffusion layer with good bonding strength. Figure 3 As shown; in addition, the tensile strength of the composite material prepared in this way can reach 287MPa, which exceeds the composite material prepared by the method in Comparative Example 1 (230MPa). This is because not only an atomic diffusion layer is formed, but also the residual stress and anisotropy left over from the hot pressing and rolling processes are avoided, and the uniformity of the organization is ensured, indicating that the arc additive method can achieve better results.

[0085] Example 2

[0086] A method for preparing a three-layer aluminum-magnesium gradient layered metal composite material by arc additive manufacturing comprises the following steps:

[0087] (a) Select magnesium alloy wire with a diameter range of 1.2-1.6 mm and a purity of >99.8% and aluminum alloy wire with a diameter range of 1.6-2.0 mm and a purity of >99.9%, and clean the surface oxides by mechanical grinding and chemical cleaning with 5% nitric acid solution;

[0088] (b) A six-axis robot system (equipped with a double-wire feeding system) provided by Fronius was prepared as an arc additive device, and a Fronius TransPulse Synergic 3200 CMT welding power source was used. The arc additive device was filled with argon as a shielding gas, and its flow rate was set to 20 L / min (fluctuation range ±5 L / min);

[0089] (c) The substrate is made of ER4043 aluminum alloy, which is preheated to 150°C to eliminate thermal stress, while the welding gun moves to the corner of the substrate.

[0090] (d) When depositing the first layer of aluminum, the wire feeding speed was set to 5 m / min, the welding power was set to 4.0 kW, the pulse frequency was set to 75 Hz, the molten pool temperature was controlled at 730 ± 20 °C, and the welding gun moved in a wavy trajectory with an amplitude of 5 mm and a wavelength of 15 mm in the horizontal direction;

[0091] (e) When the deposition of the first layer of aluminum transitions to the deposition of the first layer of magnesium, the magnesium wire is immediately switched, the wire feeding speed is rapidly increased from 5m / min to 7m / min, the welding power is rapidly reduced to 3.0kW, the pulse frequency is increased to 175Hz, and the molten pool temperature rapidly decreases linearly to 670±10℃ over time. At the same time, the substrate is rotated 90° clockwise, and the welding gun is moved to another corner of the substrate;

[0092] (f) When depositing the first layer of magnesium, the wire feeding speed was maintained at 7 m / min, the welding power was maintained at about 3.0 kW, the pulse frequency was 175 Hz, the molten pool temperature was controlled at 670 ± 10 °C, and the welding gun moved in a wavy trajectory with an amplitude of 5 mm and a wavelength of 15 mm in a direction perpendicular to the previous one;

[0093] (g) When the deposition of the first layer of magnesium transitioned to the deposition of the second layer of aluminum, aluminum wire was immediately switched to aluminum wire, the wire feeding speed was quickly restored from 7m / min to 5m / min, the welding power was quickly increased to 4.2kW, the pulse frequency was reduced to 80Hz, and the molten pool temperature rapidly increased linearly to 730±20℃ over time. At the same time, the substrate was rotated 90° clockwise again, and the welding gun was moved to another corner of the substrate;

[0094] (h) When depositing the second layer of aluminum, the wire feeding speed is maintained at 5 m / min, the welding power is maintained at about 4.2 kW, the pulse frequency is 80 Hz, the molten pool temperature is controlled at 730 ± 20 °C, and the welding gun again moves in a wavy trajectory with an amplitude of 5 mm and a wavelength of 15 mm in the horizontal direction;

[0095] (i) Repeat the operation (e) to (h) until the third layer of aluminum is deposited;

[0096] (j) Use a small current (≤1.5kW) to fill the arc pit in the arc closure stage to prevent shrinkage cracks. Clean the residual welding wire after turning off the gas.

[0097] The experimental test results show that the material obtained by the method of Example 2 successfully reduces the weight by 10.16% compared with the aluminum alloy material of the same volume. In addition, the strength of the magnesium / aluminum interface of the material is increased to about 203MPa, and the tensile strength can be increased to 294MPa.

Claims

1. A method for preparing an aluminum-magnesium gradient layered metal composite material, characterized in that: The steps include: Feeding aluminum alloy wire into the arc area of ​​the welding system to melt and deposit on the substrate to form the first layer of aluminum; When the first layer of aluminum has not yet completely solidified, the magnesium alloy wire is fed into the arc area of ​​the welding system to melt and deposit on the aluminum layer to form the first layer of magnesium; When the first layer of magnesium has not yet completely solidified, the aluminum alloy wire is fed into the arc area of ​​the welding system to melt and deposit on the magnesium layer to form a second layer of aluminum, thereby obtaining an aluminum-magnesium gradient layered metal composite material.

2. The method for preparing the aluminum-magnesium gradient layered metal composite material according to claim 1, characterized in that: The method further comprises: When the second layer of aluminum has not yet completely solidified, a magnesium alloy wire is fed into the arc area of ​​the welding system to melt and deposit on the aluminum layer to form a second layer of magnesium; When the second layer of magnesium has not yet completely solidified, the magnesium alloy wire is fed into the arc area of ​​the welding system to melt, and is deposited on the magnesium layer to form a third layer of aluminum, thereby obtaining an aluminum-magnesium gradient layered metal composite material.

3. The method for preparing the aluminum-magnesium gradient layered metal composite material according to claim 1 or 2, characterized in that: The thickness of each aluminum layer is 2~3mm, and the thickness of each magnesium layer is 1~2mm.

4. The method for preparing the aluminum-magnesium gradient layered metal composite material according to claim 1 or 2, characterized in that: The diameter of magnesium alloy wire is 1.2~1.6mm, and the diameter of aluminum alloy wire is 1.6~2.0mm; the purity of magnesium in magnesium alloy is greater than 99.8%, and the purity of aluminum in aluminum alloy is greater than 99.9%.

5. The method for preparing the aluminum-magnesium gradient layered metal composite material according to claim 1 or 2, characterized in that: The wire feeding speed of aluminum alloy wire is 4~6m / min; the wire feeding speed of magnesium alloy wire is 6-8m / min; the wire feeding speed in the transition zone between aluminum / magnesium is 5~7m / min.

6. The method for preparing the aluminum-magnesium gradient layered metal composite material according to claim 1 or 2, characterized in that: The welding power of the aluminum layer is 3.0~4.5 kW, and the pulse frequency is 50~100 Hz; the welding power of the magnesium layer is 2.5~3.5 kW, and the pulse frequency is 100~200 Hz; alternating hot and cold pulses are used in the transition zone between aluminum / magnesium.

7. The method for preparing the aluminum-magnesium gradient layered metal composite material according to claim 1 or 2, characterized in that: The welding speed is 0.3~0.8m / min; when depositing the aluminum layer, the temperature in the arc is 700~750℃; when depositing the magnesium layer, the temperature in the arc is about 660~680℃. In the transition period between depositing the magnesium layer and depositing the aluminum layer, the temperature in the arc changes linearly between 660~750℃.

8. The method for preparing the aluminum-magnesium gradient layered metal composite material according to claim 1 or 2, characterized in that: The substrate is made of aluminum alloy ER4043.

9. The method for preparing the aluminum-magnesium gradient layered metal composite material according to claim 1 or 2, characterized in that: After depositing each metal layer, the substrate is rotated 90° clockwise and the welding gun is moved perpendicularly to the previous layer to form a wavy interlayer staggered structure.

10. An aluminum-magnesium gradient layered metal composite material, characterized in that: Prepared by the preparation method according to any one of claims 1 to 9.

Images