Surface brightening method of rare earth magnesium alloy wire for electric arc additive material

Abstract

The invention discloses a method for brightening the surface of a rare earth magnesium alloy wire for electric arc additive manufacturing, and belongs to the technical field of metal material forming processes. The process comprises the following steps: wetting a wire material; ultrasonically cleaning with a cleaning agent; cleaning for the second time; and drying the wire. The method is used for solving the problem that a graphite layer on the surface of the wire is difficult to peel off after high-temperature drawing, the multiple ultrasonic cleaning method is adopted, efficient cleaning of the wire is achieved, the graphite protective layer can be thoroughly removed, damage to the wire is small, the cleaning efficiency is high, the application range is wide, and the method is suitable for industrial production. And meanwhile, an oxide layer formed in the wire preparation process can be synchronously removed, so that the surface state of the wire is remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of metal material forming technology, specifically relating to a method for surface brightening of rare earth magnesium alloy wire for arc additive manufacturing. Background Technology

[0002] Rare earth magnesium alloys have attracted widespread attention in recent years in fields such as aerospace, rail transportation, and the automotive industry due to their low density, high specific strength, and excellent load-bearing capacity. The introduction of rare earth elements significantly improves the mechanical properties, thermal stability, and corrosion resistance of the alloys. However, when using arc additive manufacturing processes to fabricate rare earth magnesium alloy parts, the surface condition of the wire has a significant impact on the microstructure and mechanical properties of the formed parts.

[0003] During the wire preparation process, a graphite protective layer is usually coated on its surface to isolate it from air and prevent oxidation during high-temperature drawing. However, this graphite layer is difficult to completely remove after forming. The graphite residue on the wire surface will significantly weaken the stability of the arc energy, hinder the wetting of molten droplets and interlayer metallurgical bonding, and thus lead to insufficient interlayer bonding, rough forming surface, and even defects.

[0004] CN116175285A discloses a method for surface polishing of medical-grade magnesium alloy wire. This method employs a wire surface polishing device with a fixed friction block. The oxide and lubricating layers are removed through contact friction between the friction block and the wire. The magnesium alloy wire passes through the device, and the tension between the friction block and the wire is adjusted by screws. The wire is pulled back to generate friction between the wire and the friction block for surface polishing. The surface is then ultrasonically cleaned with alcohol and dried. After this surface treatment, the magnesium alloy wire surface is smooth, effectively removing the oxide and lubricating layers. However, this patent causes damage to the wire surface. CN119608828A discloses a method for cleaning graphite lubricant residue from the surface of hot-drawn magnesium alloy wire. The method involves first immersing the magnesium alloy wire in an acid pickling solution; then washing the acid-washed wire with water; finally immersing the washed wire in an alkaline pickling solution; and finally washing and drying the alkaline-washed wire. This method solves the technical problem of poor treatment effect and reduced wire smoothness in existing methods for removing the graphite lubricant layer from magnesium alloy wire. However, this patent uses acidic or alkaline cleaning agents to remove graphite, which carries the risk of substrate corrosion.

[0005] In summary, existing common removal processes (such as mechanical grinding, chemical pickling, or organic solvent cleaning) often have problems such as rough operation, poor selectivity, easy damage to the substrate surface, or secondary pollution, making it difficult to meet the higher requirements of arc additive manufacturing for the cleanliness and brightness of the wire surface.

[0006] Based on this, the present invention is proposed. Summary of the Invention

[0007] The purpose of this invention is to provide a method for brightening the surface of rare earth magnesium alloy wire for arc additive manufacturing. This invention employs a multi-ultrasonic cleaning method to achieve efficient cleaning of the wire. This method can not only completely remove the graphite protective layer, but also cause less damage to the wire, has high cleaning efficiency, and a wide range of applications. At the same time, it can also remove the oxide layer formed during the wire preparation process, thereby significantly improving the surface condition of the wire.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for surface brightening of rare earth magnesium alloy wire for arc additive manufacturing includes the following steps: Step 1: Wetting treatment of silk material Preheat the isopropanol solution, press the filament into the isopropanol solution, and use a probe-type ultrasonic cleaner to perform ultrasonic cleaning to wet and increase the wettability of the surface graphite layer. Step 2: Ultrasonic cleaning Heat the cleaning agent, press the filament into the cleaning agent, and use a probe-type ultrasonic cleaner to perform ultrasonic cleaning to remove the surface graphite. Step 3: Second cleaning The anhydrous ethanol solution is heated, and the filament is pressed into the anhydrous ethanol solution. A probe-type ultrasonic cleaner is used for secondary ultrasonic cleaning to remove the residual cleaning agent and at the same time, the impact force generated by cavitation and micro-jets are used to remove the surface oxide layer. Step 4: Drying the silk.

[0009] Furthermore, the method also includes: pretreating the filament with low-temperature plasma before step one.

[0010] Furthermore, the process of treating the filament with low-temperature plasma is as follows: using an Ar / O2 mixed gas, under conditions of 50-200 Pa and 100-300 W radio frequency power, for 5-15 min.

[0011] This step aims to utilize high-energy electrons, ions, and active groups (such as O) in the plasma. + O2 + The process involves bombardment and activation with substances such as oxygen (O3, etc.) to effectively decompose organic pollutants and weak boundary layers on the surface of the filament, significantly improve the wettability and penetration of subsequent cleaning agents, enhance the efficiency of graphite layer peeling, and thus strengthen the overall cleaning effect.

[0012] Furthermore, the volume ratio of Ar to O2 is 90:10 to 80:20. Oxygen provides reactive oxygen species for the oxidative decomposition of organic matter; argon is used to maintain plasma stability and enhance the activation effect.

[0013] Furthermore, in step one, the volume concentration of isopropanol in the isopropanol solution is 80-100%.

[0014] Furthermore, in step one, the isopropanol solution is preheated to 70-80°C.

[0015] Furthermore, in step one, the ultrasonic cleaning frequency is 30-50 kHz, the power density is 1-2 W / mL, and the ultrasonic time is 30-60 min.

[0016] Furthermore, in step two, the cleaning agent contains 0.5 wt%-0.8 wt% sodium polyacrylate, 0.3 wt%-0.7 wt% sodium dodecyl sulfate, 0.2 wt%-0.5 wt% fatty alcohol polyoxyethylene ether, and the remainder is water.

[0017] Furthermore, in step two, the cleaning agent contains 0.5 wt%-0.8 wt% sodium polyacrylate, 0.3 wt%-0.7 wt% sodium dodecyl sulfate, 0.2 wt%-0.5 wt% fatty alcohol polyoxyethylene ether, 0.01-0.05 wt% nano-silica particles and / or nano-alumina particles, with the remainder being water. Cleaning in the above cleaning agent can further enhance the ultrasonic cavitation effect and mechanical scrubbing action, thereby improving the graphite removal rate.

[0018] Furthermore, the particle size of the nano-silica particles is 10-50 nm, and the particle size of the nano-alumina particles is 50-100 nm.

[0019] Rare earth magnesium alloys have relatively low hardness (typically below 100 HV). When the particle size of nanoparticles is strictly controlled below 100 nm, their size is much smaller than the microscopic protrusions and grain boundaries on the material surface. Therefore, they cannot produce an effective "plowing" or "cutting" action, resulting in almost no measurable scratches or damage to the substrate. The core of ultrasonic cleaning is the "cavitation effect"—the formation and violent collapse of tiny bubbles in a liquid. Nanoparticles act as additional cavitation nuclei in the liquid, significantly increasing the number of cavitation bubbles. Nano-silica particles have a particle size of 10-50 nm, and nano-alumina particles have a particle size of 50-100 nm. Particles in this size range have extremely high specific surface areas, enabling them to efficiently transfer ultrasonic energy and convert it into mechanical energy (microjets and shock waves). When cavitation bubbles collapse on the particle surface, the resulting microjets have stronger and more concentrated energy, which can more effectively peel off graphite layers and oxide films. Meanwhile, with the assistance of sodium dodecyl sulfate in the formula, 10-50 nm nano silica particles or 50-100 nm nano alumina particles can form a stable and uniform suspension in water-based cleaning agents, avoiding sedimentation failure or local scratches caused by particle agglomeration.

[0020] Furthermore, in step two, the heating temperature is 50-70℃.

[0021] Furthermore, in step two, the ultrasonic cleaning frequency is 20-40 kHz, the power density is 2-3 W / mL, and the ultrasonic time is 30-60 min.

[0022] Furthermore, in step three, the volume concentration of ethanol in the anhydrous ethanol solution is 80-100%.

[0023] Furthermore, in step three, the heating temperature of the anhydrous ethanol solution is 50-70℃.

[0024] Furthermore, in step three, the frequency of the secondary ultrasonic cleaning is 80-100 kHz, the power density range is 0.2-0.8 W / mL, and the ultrasonic time is 30-60 min.

[0025] Furthermore, in steps two and three, a microcurrent electrode Pt mesh is set in the ultrasonic cleaning device, and a DC voltage of 0.5-2V is applied to promote the peeling of the oxide layer by electrochemical polarization.

[0026] Furthermore, in step four, the drying temperature is 80-100℃ and the drying time is 4-6 hours.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Efficient and thorough removal of graphite protective layer: Through multiple ultrasonic cleaning processes, combined with a specific formula of cleaning agent and optimized process parameters, the graphite protective layer on the surface of the wire can be removed efficiently and thoroughly, avoiding the adverse effects of graphite residue on arc stability and forming quality.

[0028] 2. Simultaneous removal of surface oxide layer: During the secondary cleaning process, the cavitation effect and micro-jet impact force generated by high-frequency ultrasound are used to effectively remove the oxide layer on the surface of the silk, further improving the surface cleanliness and gloss of the silk.

[0029] 3. Minimal damage to the substrate: The use of mild chemical reagents and controllable ultrasonic parameters avoids mechanical damage or chemical corrosion to the surface of rare earth magnesium alloy wire, thus maintaining the original properties and dimensional accuracy of the wire.

[0030] 4. High cleaning efficiency and wide applicability: The entire process is reasonably designed, easy to operate, and highly efficient. It is suitable for rare earth magnesium alloy wires of various specifications and compositions, and has good versatility and scalability.

[0031] 5. Environmental protection and operational safety: The cleaning agents used have controllable composition, are odorless and low in toxicity, and do not require strong acids or organic solvents in the process, reducing harm to the environment and operators, and meeting the requirements of green manufacturing.

[0032] 6. Improve the quality of additive manufacturing: By improving the surface condition of the filament, the arc stability, droplet wetting and interlayer bonding force in the electric arc additive manufacturing process are effectively improved, thereby significantly improving the surface quality, microstructure uniformity and mechanical properties of the formed parts. Attached Figure Description

[0033] Figure 1 A diagram of the equipment used in the method of this invention; Figure 2 The tensile properties of the filament before treatment in Example 2; Figure 3 The tensile properties of the filament after treatment in Example 2; Figure 4 The morphology of the wire material after surface treatment in Example 2; In the diagram: 1. Tensioning wheel; 2. Probe-type ultrasonic instrument; 3. Wire; 4. Isopropanol solution; 5. Cleaning agent solution; 6. Anhydrous ethanol solution; 7. Drying oven. Detailed Implementation

[0034] The technical solution and effects of the present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0035] The equipment used in the method of this invention is shown in the figure below. Figure 1 As shown, it includes several tensioning wheels 1, and the filament 3 is wound on the tensioning wheels 1. Driven by the tensioning wheels 1, the filament is sequentially passed through isopropanol solution 4, cleaning agent solution 5, anhydrous ethanol solution 6 and drying oven 7. Probe-type ultrasonic instruments 7 are placed in isopropanol solution 4, cleaning agent solution 5 and anhydrous ethanol solution 6.

[0036] The equipment used also includes a radio frequency (RF) type low-temperature plasma generator, and the filament passes through the plasma processing chamber through a tensioning wheel system to achieve continuous or step-by-step processing.

[0037] And in ultrasonic devices containing cleaning solutions and anhydrous ethanol solutions, microcurrent electrodes Pt mesh are laid out and a DC voltage of 0.5-2V is applied. Example 1

[0038] This embodiment of a method for surface brightening of rare earth magnesium alloy wire for arc additive manufacturing includes the following steps: Step 1: Wetting treatment of silk material Preheat a 90% volume concentration isopropanol solution to 70°C, press the filament into the isopropanol solution, and use a probe-type ultrasonic cleaner to perform ultrasonic cleaning to wet and increase the wettability of the surface graphite layer. The ultrasonic cleaning frequency was 35 kHz, the power density was 1.5 W / mL, and the ultrasonic time was 60 min.

[0039] Step 2: Ultrasonic cleaning Heat the cleaning agent to 50°C, press the filament into the cleaning agent, and use a probe-type ultrasonic cleaner to perform ultrasonic cleaning to remove the surface graphite. The ultrasonic cleaning frequency was 35 kHz, the power density was 3 W / mL, and the ultrasonic time was 50 min.

[0040] The cleaning agent contains 0.5 wt% sodium polyacrylate, 0.6 wt% sodium dodecyl sulfate, 0.3 wt% fatty alcohol polyoxyethylene ether, and the remainder is water.

[0041] Step 3: Second cleaning An 85% anhydrous ethanol solution was heated to 50°C, and the filament was pressed into the anhydrous ethanol solution. A probe-type ultrasonic cleaner was used for secondary ultrasonic cleaning to remove the residual cleaning agent and at the same time, the impact force generated by cavitation and micro-jets were used to remove the surface oxide layer. The secondary ultrasonic cleaning was performed at a frequency of 100 kHz, a power density range of 0.5 W / mL, and an ultrasonic time of 60 min.

[0042] Step 4: Drying the silk material at 80℃ for 6 hours. Example 2

[0043] This embodiment of a method for surface brightening of rare earth magnesium alloy wire for arc additive manufacturing includes the following steps: Step 1: Wetting treatment of silk material Preheat a 95% volume concentration isopropanol solution to 80°C, press the filament into the isopropanol solution, and use a probe-type ultrasonic cleaner to perform ultrasonic cleaning to wet and increase the wettability of the surface graphite layer. The ultrasonic cleaning frequency was 50 kHz, the power density was 2.0 W / mL, and the ultrasonic time was 50 min.

[0044] Step 2: Ultrasonic cleaning Heat the cleaning agent to 60°C, press the filament into the cleaning agent, and use a probe-type ultrasonic cleaner to perform ultrasonic cleaning to remove the surface graphite. The ultrasonic cleaning frequency was 40 kHz, the power density was 2.5 W / mL, and the ultrasonic time was 45 min.

[0045] The cleaning agent contains 0.6 wt% sodium polyacrylate, 0.5 wt% sodium dodecyl sulfate, 0.4 wt% fatty alcohol polyoxyethylene ether, 0.03 wt% nano silica particles, 0.05 wt% nano alumina particles, and the remainder is water.

[0046] Step 3: Second cleaning A 90% anhydrous ethanol solution was heated to 60°C. The filament was then pressed into the anhydrous ethanol solution and subjected to a second ultrasonic cleaning using a probe-type ultrasonic cleaner. This process removed the residual cleaning agent and simultaneously used the impact force generated by cavitation and micro-jets to remove the surface oxide layer. The secondary ultrasonic cleaning was performed at a frequency of 100 kHz, a power density range of 0.8 W / mL, and an ultrasonic time of 60 min.

[0047] Step 4: Drying the silk material at 100℃ for 4 hours.

[0048] Figure 2 Tensile properties of the wire before treatment. Figure 3 To assess the tensile properties of the filament after treatment, a comparison of the tensile properties before and after treatment showed that the tensile properties of the filament not only did not decrease after treatment, but the tensile properties were actually enhanced by the synergistic effect of the nano-silica particles and nano-alumina particles and the ultrasonic cavitation effect during ultrasonic cleaning, which generated an impact stress layer on the outer surface of the filament. Figure 4 The image shows the morphology of the wire surface after treatment. After optimized cleaning process, the wire surface exhibits a uniform metallic luster. Example 3

[0049] This embodiment of a method for surface brightening of rare earth magnesium alloy wire for arc additive manufacturing includes the following steps: Step 1: Wire Pretreatment The filament was fed into the low-temperature plasma treatment chamber, and after being evacuated to 50 Pa, an Ar / O2 mixed gas (volume ratio of 90:10) was introduced to maintain the pressure at 100 Pa. The radio frequency power supply was turned on, the power was set to 300 W, and the treatment time was 10 min.

[0050] Step 2: Wetting treatment of the silk material Preheat a 95% volume concentration isopropanol solution to 75°C, press the filament into the isopropanol solution, and use a probe-type ultrasonic cleaner to perform ultrasonic cleaning to wet and increase the wettability of the surface graphite layer. The ultrasonic cleaning frequency was 40 kHz, the power density was 1.5 W / mL, and the ultrasonic time was 40 min.

[0051] Step 3: Ultrasonic cleaning The cleaning agent is heated to 55°C. A microcurrent electrode Pt mesh is set in the ultrasonic cleaning device, and a DC voltage of 1.5 V is applied. The filament is pressed into the cleaning agent, and ultrasonic cleaning is performed using a probe-type ultrasonic instrument to remove the surface graphite. The ultrasonic cleaning frequency was 35 kHz, the power density was 3 W / mL, and the ultrasonic time was 40 min.

[0052] The cleaning agent contains 0.5 wt% sodium polyacrylate, 0.6 wt% sodium dodecyl sulfate, 0.3 wt% fatty alcohol polyoxyethylene ether, 0.03 wt% nano silica particles, 0.05 wt% nano alumina particles, and the remainder is water.

[0053] Step 4: Second cleaning An 85% volume concentration of anhydrous ethanol solution is heated to 65°C. A microcurrent electrode Pt mesh is set in the ultrasonic cleaning device, and a DC voltage of 1.5 V is applied. The wire is pressed into the anhydrous ethanol solution, and a probe-type ultrasonic instrument is used for secondary ultrasonic cleaning to remove the residual cleaning agent. At the same time, the impact force generated by cavitation and the micro-jet are used to remove the surface oxide layer. The secondary ultrasonic cleaning was performed at a frequency of 100 kHz, a power density range of 0.6 W / mL, and an ultrasonic time of 45 min.

[0054] Step 5: Drying the silk material at 80℃ for 6 hours.

[0055] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for surface brightening of rare earth magnesium alloy wire for arc additive manufacturing, characterized in that, The method includes the following steps: Step 1: Wetting treatment of silk material Preheat the isopropanol solution, press the filament into the isopropanol solution, and use a probe-type ultrasonic cleaner to perform ultrasonic cleaning to wet and increase the wettability of the surface graphite layer. Step 2: Ultrasonic cleaning Heat the cleaning agent, press the filament into the cleaning agent, and use a probe-type ultrasonic cleaner to perform ultrasonic cleaning to remove the surface graphite. Step 3: Second cleaning The anhydrous ethanol solution is heated, and the filament is pressed into the anhydrous ethanol solution. A probe-type ultrasonic cleaner is used for secondary ultrasonic cleaning to remove the residual cleaning agent and at the same time, the impact force generated by cavitation and micro-jets are used to remove the surface oxide layer. Step 4: Drying the silk.

2. The method according to claim 1, characterized in that, In step one, the isopropanol solution is preheated to 70-80℃.

3. The method according to claim 1, characterized in that, In step one, the ultrasonic cleaning frequency is 30-50kHz, the power density is 1-2 W / mL, and the ultrasonic time is 30-60 min.

4. The method according to claim 1, characterized in that, In step two, the cleaning agent contains 0.5 wt%-0.8 wt% sodium polyacrylate, 0.3 wt%-0.7 wt% sodium dodecyl sulfate, 0.2 wt%-0.5 wt% fatty alcohol polyoxyethylene ether, and the remainder is water.

5. The method according to claim 1, characterized in that, In step two, the cleaning agent contains 0.5 wt%-0.8 wt% sodium polyacrylate, 0.3 wt%-0.7 wt% sodium dodecyl sulfate, 0.2 wt%-0.5 wt% fatty alcohol polyoxyethylene ether, 0.01-0.05 wt% nano silica particles and / or nano alumina particles, with the remainder being water.

6. The method according to claim 5, characterized in that, The nano-silica particles have a particle size of 10-50 nm, and the nano-alumina particles have a particle size of 50-100 nm.

7. The method according to claim 1, characterized in that, In step two, the heating temperature is 50-70℃.

8. The method according to claim 1, characterized in that, In step two, the ultrasonic cleaning frequency is 20-40kHz, the power density is 2-3 W / mL, and the ultrasonic time is 30-60 min.

9. The method according to claim 1, characterized in that, In step three, the heating temperature of the anhydrous ethanol solution is 50-70℃.

10. The method according to claim 1, characterized in that, In step three, the frequency of the secondary ultrasonic cleaning is 80-100 kHz, the power density range is 0.2-0.8 W / mL, and the ultrasonic time is 30-60 min.

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