Method for rapidly acquiring dynamic mechanical properties of surface deposition layer of electromagnetic emission track

Abstract

The invention relates to a method for quickly acquiring dynamic mechanical properties of a surface layer of an electromagnetic launching track. Belongs to the technical field of electromagnetic track launching. The armature material spraying layer is prepared on the electromagnetic track material through electric arc spraying, interface diffusion of the track and the armature material is promoted through electric pulse treatment, the internal structure and performance of the spraying layer are regulated and controlled through heat treatment, and finally a reconstructed sample piece with the size meeting dynamic mechanical property test research is obtained. And during electric treatment, current flows through the electromagnetic track material from the armature material spraying layer. According to the method, a large number of reliable samples can be obtained in an extremely short time, and necessary conditions are provided for optimization of electromagnetic emission armatures and track materials and scientific and effective evaluation of electromagnetic emission life.

Description

Technical Field

[0001] This invention relates to a method for rapidly obtaining the dynamic mechanical properties of the surface layer of an electromagnetic launch track; it belongs to the field of electromagnetic track launch technology. Background Technology

[0002] Electromagnetic orbital launch is a modern launch method that utilizes electromagnetic energy to achieve ultra-high-speed launch. It consists of a high-power pulsed power supply, two parallel metal rails, and a current-carrying armature in the middle. During launch, the pulsed current flows into one rail, passes through the armature, and flows out of the other rail, creating a strong magnetic field between the parallel rails. Under the influence of this strong magnetic field, the current-carrying armature generates a Lorentz force, which propels the armature out at high speed.

[0003] Since the rails are reused during service, changes in their surface condition and performance have a decisive impact on launch behavior and service life. During actual launches, the armature, under high current density, strong thermo-mechanical coupling, and high-speed sliding, easily transfers to the rail surface, forming a deposit layer. With increasing launch frequency, the contact between the armature and the rail changes from the initial rail-armature contact to rail-deposit layer-armature contact. The dynamic mechanical properties of the deposit layer directly affect the dynamics of the armature's movement, thus impacting launch accuracy. Therefore, the dynamic mechanical behavior of the deposit layer is a key factor determining the launch behavior and stability of electromagnetic rails.

[0004] Currently, researchers have conducted relevant performance tests on the deposited layers on the orbital surface. Chinese patent CN202311648951.5 discloses a device and method for three-dimensional imaging of the composition and hardness testing of electromagnetic orbital deposits. This invention uses laser triggering and LIBS optical tomography data analysis to achieve in-situ detection of the morphology and hardness of the orbital surface deposits, but the detected performance is static mechanical property. In addition, most researchers study the microstructure and mechanical properties of the deposited layers by disassembling and sampling the actual launched orbits. However, due to the fit between the armature and the orbit, the deposited layer is only at the micrometer level thick, which cannot meet the requirements for dynamic mechanical behavior testing samples, making it difficult to obtain the dynamic mechanical properties of the orbital surface deposited layers. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention proposes for the first time a method, under laboratory conditions, to rapidly reconstruct a sample whose microstructure and static mechanical properties are similar to those of actual emission deposition and which meets the size requirements for dynamic mechanical performance testing by combining arc spraying, electric pulse diffusion, and heat treatment. This allows for the acquisition of the dynamic mechanical properties of the deposition layer.

[0006] The present invention aims to provide a reasonable method for rapidly reconstructing samples with similar microstructure and static mechanical properties to deposited layers under laboratory conditions, providing sufficient experimental samples for obtaining the dynamic mechanical behavior of deposited layers on the surface of electromagnetic launch orbits.

[0007] To verify the reliability of this invention, it is necessary to obtain the orbital surface deposition layer from different launch cycles to determine its microstructure and static mechanical properties. Subsequently, the reconstructed sample and the actual sample are matched to further verify the reliability of the efficiently constructed sample according to this invention.

[0008] The reconstruction process designed in this invention includes: preparing an armature material coating layer by arc spraying on the electromagnetic track material; promoting interfacial diffusion between the track and the armature material by electric pulse treatment; controlling the internal structure and properties of the coating layer by heat treatment; and finally obtaining a reconstructed sample whose dimensions meet the requirements for dynamic mechanical performance testing. During the electrical treatment, current flows from the armature material coating layer through the electromagnetic track material.

[0009] Preferably, the armature is made of aluminum alloy and the track is made of copper alloy.

[0010] In practical applications, the aluminum alloy is selected from at least one of 7075Al alloy and 6061Al alloy. The copper alloy is selected from one of CuCrZr alloy and ODS-Cu.

[0011] In this invention, the composition of the aluminum alloy, by mass percentage, includes: Zn 5.1~6.1%, Mg 2.1~2.9%, Cu 1.2~2.0%, Fe 0.2~0.5%, impurities less than or equal to 0.4%, and the remainder being Al.

[0012] In this invention, the composition of the copper alloy, by mass percentage, includes: Mg 0.05~0.3%, Cr 0.2~1.0%, Zr 0.03~0.25%, impurities less than or equal to 0.25%, and the remainder being Cu.

[0013] In this invention, the current is set to flow from the armature material coating layer through the electromagnetic track material to utilize the "electron wind" effect in electromigration to accelerate the diffusion of Cu atoms from the electromagnetic track material to the Al atoms in the coating layer, thereby simulating the diffusion process of Cu atoms from the track material into the deposition layer during actual launch. When the current flows from the Al layer to the Cu layer, conductive electrons actually drift from the Cu layer to the Al layer. During the scattering process of electrons and atoms, the energy of the drifting electrons is transferred to the Cu atoms in the diffusion transition state, thus generating the "electron wind" effect and accelerating the diffusion process of Cu atoms.

[0014] This invention utilizes arc spraying technology, employing track material as the substrate and armature material as the spraying material. A coating layer with a thickness meeting the requirements for dynamic mechanical performance testing is sprayed onto the track substrate material. The spraying process uses a voltage of 10-60V, a current of 50-200 A, an air pressure of 0.2-0.6MPa, and a wire feed rate of 2-15 mm / s. Preferably, the voltage is 20-40V, more preferably 28-32V; the current is preferably 100-150 A, more preferably 130-145A; the air pressure is preferably 0.3-0.5 MPa, more preferably 0.41-0.46 MPa; and the wire feed rate is preferably 6-10 mm / s, more preferably 7-9 mm / s.

[0015] The arc spraying technology used in this invention employs a robotic arm to control the operating parameters of the spray gun nozzle, with a movement speed of 500 mm / s. The number of spray passes is 15-30, and the coating thickness is 1-2 mm. The resulting coating provides the necessary sample for subsequent electro-pulse treatment to promote interfacial diffusion.

[0016] This invention uses electrical pulse treatment to promote interfacial diffusion between the orbital and armature materials, simulating the diffusion process of Cu atoms and other atoms in the orbital material into the deposition layer driven by pulsed current during repeated launches. The pulsed current-treated sample is 5 mm long, 5 mm wide, and 4 mm high. The pulsed current flows from the armature material layer (e.g., a sprayed Al or aluminum alloy layer) to the orbital substrate material layer (e.g., a copper or Cu alloy layer). The power supply is set with a current intensity of 500-1200 A, corresponding to a current density of 2000-4800 A / cm². 2 The pulsed current processing time is 5-30 minutes. The preferred current intensity is 700-1000 A, corresponding to a current density of 2800-4000 A / cm². 2 The sprayed coating, after being diffused by electrical pulses, provides the necessary sample for subsequent microstructure control during heat treatment.

[0017] In this invention, when the electrical pulse processing time and current density are less than the range described in the invention, the diffusion effect of Cu atoms in the sprayed coating is not obvious. When the electrical pulse processing time and current density are greater than the range described in the invention, the heat accumulation input and electromigration effect are too strong, resulting in severe ablation and remelting of the sprayed coating, making it difficult to obtain a reconstruction result that is similar and repeatable.

[0018] The electrical pulse processing step in the invention is to simulate the process in which pulse current causes Cu atoms in the orbit to diffuse into the deposition layer during actual launch, thereby accelerating the diffusion of Cu atoms into the spray coating during the reconstruction process to achieve a similar effect to the Cu atom content in the deposition layer during actual launch.

[0019] This invention uses heat treatment to regulate the microstructure within the sprayed layer after pulse treatment, ensuring that the microstructure composition of the reconstructed deposition layer matches that of the actual deposition layer on the launch trajectory. The heat treatment temperature is 300-600℃, and the time is 1-8 h. Preferably, the heat treatment temperature is 400-500℃, and the preferred time is 2-6 h. After heat treatment, a reconstructed sample for dynamic mechanical property testing of the deposition layer is finally obtained.

[0020] The heat treatment temperature in this invention is selected based on the Cu-Al phase diagram and the microstructure within the deposited layer during actual emission. Within this temperature range, the precipitation of the target microstructure can be effectively promoted. When the heat treatment time is less than the time described in this invention, the amount of target microstructure precipitated in the sprayed coating is insufficient. Conversely, when the heat treatment time is too long, the amount of target microstructure precipitated in the sprayed coating is excessive, resulting in a difference between the static mechanical properties of the reconstructed deposited layer and the actual emission deposited layer.

[0021] The heat treatment process described in this invention is set after the electric pulse diffusion treatment. Based on the electric pulse promoting the diffusion of Cu atoms into the sprayed coating, under the premise that there is a certain amount of Cu atoms in the sprayed coating, heat treatment is then used to promote the reaction between Cu atoms and Al atoms, thereby precipitating microstructure components in the sprayed coating that are similar to the deposited layer in the actual launch process.

[0022] The samples reconstructed using this invention were shown, after X-ray diffraction analysis and nanoindentation testing, to have a microstructure and static mechanical properties similar to the deposition layer on the orbital surface during actual launch.

[0023] The dynamic mechanical performance test specimen reconstructed in this invention is achieved through the synergistic effect of arc spraying, electric pulse diffusion treatment, and heat treatment, with a fixed implementation sequence. First, an armature material coating of a certain thickness is sprayed onto the track material using arc spraying to simulate the process of armature material melting and splashing onto the track surface to form a deposition layer during actual launch. The electric pulse diffusion treatment is performed on the specimen obtained after arc spraying, aiming to promote the diffusion of Cu atoms from the track material into the spray coating layer using pulsed current, simulating the diffusion of Cu atoms from the track into the deposition layer during actual launch. The heat treatment process is performed on the specimen obtained after electric pulse treatment, aiming to further promote the reaction between Cu atoms diffused into the spray coating layer and Al atoms, thereby precipitating a structure similar to the deposition layer on the track surface after actual launch within the spray coating layer. Attached Figure Description

[0024] Appendix Figure 1 This is a schematic diagram of the electrical pulse processing process;

[0025] Appendix Figure 2 The composition of the deposition layer on the orbital surface after actual launch;

[0026] Appendix Figure 3 This refers to the interfacial diffusion phenomenon after electrical pulse treatment in Example 1;

[0027] Appendix Figure 4 The microstructure of the reconstructed deposited layer material after heat treatment in Example 1;

[0028] Appendix Figure 5 This is the interface diffusion phenomenon after electrical pulse treatment in Comparative Example 2. Detailed Implementation

[0029] In the examples and comparative examples, the coating material used was the armature material (specifically, 7075Al alloy), and the coating substrate material was the track material (specifically, CuCrZr material, grade C18150). During the electrical pulse processing, the sample dimensions were 5 mm in length, 5 mm in width, and 4 mm in height.

[0030] Example 1

[0031] First, an Al alloy coating was prepared on a Cu alloy substrate using arc spraying. The spraying voltage was 30 V, the current was 140 A, the air pressure was 0.45 MPa, and the wire feed rate was 8 mm / s. A robotic arm controlled the movement of the spray gun nozzle at a speed of 500 mm / s. The spraying was performed in 21 passes, resulting in a coating thickness of 1.7 mm.

[0032] The sprayed sample was then subjected to an electrical pulse treatment. The sample was 5 mm long, 5 mm wide, and 4 mm high. The pulsed current flowed from the sprayed Al layer to the Cu layer. The power supply was set with a current intensity of 900 A, corresponding to a current density of 3600 A / cm². 2 The pulsed current treatment time was 15 min. The diffusion of elements at the Cu / Al interface after the pulsed current treatment is as follows: Figure 3 As shown, Figure 3 (a) is a diffusion cross-sectional topography diagram, and (b) is a diffusion element distribution diagram.

[0033] Finally, the samples treated with the electrical pulse were subjected to heat treatment to regulate the microstructure of the diffused samples. The heat treatment temperature was 380 ℃, and the holding time was 4 h. The tissue composition of the samples after heat treatment is as follows: Figure 4 As shown, the composition is consistent with the actual composition of the emission deposition layer.

[0034] The static mechanical properties of the reconstructed deposition layer were tested by nanoindentation. The nanoindentation hardness of the reconstructed deposition layer was 2.42 GPa and the elastic modulus was 67.7 GPa. The performance error of the nanoindentation hardness was 5.6% and the elastic modulus was 8.6% (the actual emission deposition layer had a nanoindentation hardness of 2.29 GPa and an elastic modulus of 74.1 GPa).

[0035] Example 2

[0036] First, an Al alloy coating was prepared on a Cu alloy substrate using arc spraying. The spraying voltage was 30 V, the current was 140 A, the air pressure was 0.45 MPa, and the wire feed rate was 8 mm / s. A robotic arm controlled the movement of the spray gun nozzle at a speed of 500 mm / s. The spraying was performed in 21 passes, resulting in a coating thickness of 1.7 mm.

[0037] The sprayed sample was then subjected to an electrical pulse treatment. The sample was 5 mm long, 5 mm wide, and 4 mm high. The pulsed current flowed from the sprayed Al layer to the Cu layer. The power supply was set with a current intensity of 700 A, corresponding to a current density of 2800 A / cm². 2 The pulse current processing time is 15 minutes.

[0038] Finally, the samples treated with the electrical pulse were subjected to heat treatment to regulate the microstructure of the diffused samples. The heat treatment temperature was 380 ℃, and the holding time was 4 h.

[0039] The static mechanical properties of the reconstructed deposition layer were tested by nanoindentation. The nanoindentation hardness of the reconstructed deposition layer was 2.11 GPa and the elastic modulus was 64.7 GPa. The performance error of the nanoindentation hardness was 7% and the elastic modulus was 12.7% (the actual emission deposition layer had a nanoindentation hardness of 2.29 GPa and an elastic modulus of 74.1 GPa).

[0040] Example 3

[0041] First, an Al alloy coating was prepared on a Cu alloy substrate using arc spraying. The spraying voltage was 30 V, the current was 140 A, the air pressure was 0.45 MPa, and the wire feed rate was 8 mm / s. A robotic arm controlled the movement of the spray gun nozzle at a speed of 500 mm / s. The spraying was performed in 21 passes, resulting in a coating thickness of 1.7 mm.

[0042] The sprayed sample was then subjected to an electrical pulse treatment. The sample was 5 mm long, 5 mm wide, and 4 mm high. The pulsed current flowed from the sprayed Al layer to the Cu layer. The power supply was set with a current intensity of 1000 A, corresponding to a current density of 4000 A / cm².2 The pulse current processing time is 15 minutes.

[0043] Finally, the samples treated with the electrical pulse were subjected to heat treatment to regulate the microstructure of the diffused samples. The heat treatment temperature was 380 ℃, and the holding time was 4 h.

[0044] The static mechanical properties of the reconstructed deposition layer were tested by nanoindentation. The nanoindentation hardness of the reconstructed deposition layer was 2.51 GPa and the elastic modulus was 82.5 GPa. The performance error of the nanoindentation hardness was 9.6% and the elastic modulus was 11.3% (the actual emission deposition layer had a nanoindentation hardness of 2.29 GPa and an elastic modulus of 74.1 GPa).

[0045] Comparative Example 1

[0046] First, an Al alloy coating was prepared on a Cu alloy substrate using arc spraying. The spraying voltage was 30 V, the current was 140 A, the air pressure was 0.45 MPa, and the wire feed rate was 8 mm / s. A robotic arm controlled the movement of the spray gun nozzle at a speed of 500 mm / s. The spraying was performed in 21 passes, resulting in a coating thickness of 1.7 mm.

[0047] The sprayed sample was then subjected to an electrical pulse treatment. The sample was 5 mm long, 5 mm wide, and 4 mm high. The pulsed current flowed from the sprayed Cu layer to the Al layer. The power supply was set with a current intensity of 900 A, corresponding to a current density of 3600 A / cm². 2 The pulse current processing time is 15 minutes.

[0048] The X-ray diffraction analysis results showed that the untreated sprayed layer lacked a precipitation process, and only a small amount of CuAl2 was present in the layer, which was significantly different from the microstructure of the deposited layer on the actual launch orbit surface.

[0049] Comparative Example 2

[0050] First, an Al alloy coating was prepared on a Cu alloy substrate using arc spraying. The spraying voltage was 30 V, the current was 140 A, the air pressure was 0.45 MPa, and the wire feed rate was 8 mm / s. A robotic arm controlled the movement of the spray gun nozzle at a speed of 500 mm / s. The spraying was performed in 21 passes, resulting in a coating thickness of 1.7 mm.

[0051] The sprayed sample was then subjected to an electrical pulse treatment. The sample was 5 mm long, 5 mm wide, and 4 mm high. The pulsed current flowed from the sprayed Al layer to the Cu layer. The power supply was set with a current intensity of 500 A, corresponding to a current density of 2000 A / cm². 2The pulsed current treatment time was 15 min. The diffusion of elements at the Cu / Al interface after the pulsed current treatment is as follows: Figure 5 As shown, Figure 5 (a) shows the cross-sectional morphology of the diffusion layer, and (b) shows the distribution of the diffusion elements. As can be seen from the figures, no obvious diffusion phenomenon occurred in the Cu / Al layer.

[0052] Comparative Example 3

[0053] First, an Al alloy coating was prepared on a Cu alloy substrate using arc spraying. The spraying voltage was 30 V, the current was 140 A, the air pressure was 0.45 MPa, and the wire feed rate was 8 mm / s. A robotic arm controlled the movement of the spray gun nozzle at a speed of 500 mm / s. The spraying was performed in 21 passes, resulting in a coating thickness of 1.7 mm.

[0054] The sprayed sample was then subjected to an electrical pulse treatment. The sample was 5 mm long, 5 mm wide, and 4 mm high. The pulsed current flowed from the sprayed Al layer to the Cu layer. The power supply was set with a current intensity of 1100 A, corresponding to a current density of 3600 A / cm². 2 The pulsed current processing time is 15 minutes. During the reconstruction process, the excessive Joule heating generated by the pulsed current caused the sprayed coating to remelt and fail.

[0055] Comparative Example 4

[0056] First, an Al alloy coating was prepared on a Cu alloy substrate using arc spraying. The spraying voltage was 30 V, the current was 140 A, the air pressure was 0.45 MPa, and the wire feed rate was 8 mm / s. A robotic arm controlled the movement of the spray gun nozzle at a speed of 500 mm / s. The spraying was performed in 21 passes, resulting in a coating thickness of 1.7 mm.

[0057] The sprayed sample was then subjected to an electrical pulse treatment. The sample was 5 mm long, 5 mm wide, and 4 mm high. The pulsed current flowed from the sprayed Al layer to the Cu layer. The power supply was set with a current intensity of 900 A, corresponding to a current density of 3600 A / cm². 2 The pulse current processing time is 15 minutes.

[0058] Finally, the samples treated with electrical pulses were subjected to heat treatment to regulate the microstructure of the diffused samples. The heat treatment temperature was 380 ℃, and the holding time was 8 h.

[0059] The static mechanical properties of the reconstructed deposition layer were tested using nanoindentation. The nanoindentation hardness of the reconstructed deposition layer was 2.74 GPa, and the elastic modulus was 89.2 GPa. The performance error was 19.6% for the nanoindentation hardness and 20.4% for the elastic modulus (the nanoindentation hardness of the deposition layer was 2.29 GPa, and the elastic modulus was 74.1 GPa). Due to the excessively long heat treatment time, the reconstructed sprayed coating layer had a higher content of CuAl phase and Al oxides, resulting in larger performance and error values ​​compared to Example 1.

Claims

1. A method for rapidly obtaining the dynamic mechanical properties of a deposition layer on the surface of an electromagnetic launch track, characterized in that: An armature material coating layer is prepared on the electromagnetic track material by arc spraying, an electric pulse treatment is used to promote the interfacial diffusion between the track and the armature material, and a heat treatment is used to regulate the internal structure and properties of the coating layer. Finally, a reconstructed sample with dimensions that meet the requirements for dynamic mechanical performance testing is obtained. During the electrical treatment, the current flows from the armature material coating layer through the electromagnetic track material.

2. The method for rapidly obtaining the dynamic mechanical properties of the deposition layer on the surface of an electromagnetic launch track according to claim 1, characterized in that: The armature is made of aluminum alloy, and the track is made of copper alloy; In practical applications, the aluminum alloy is selected from at least one of 7075Al alloy and 6061Al alloy; the copper alloy is selected from one of CuCrZr alloy and ODS-Cu.

3. The method for rapidly obtaining the dynamic mechanical properties of the deposition layer on the surface of an electromagnetic launch track according to claim 1, characterized in that: The composition of aluminum alloys, by mass percentage, includes: Zn 5.1~6.1%, Mg 2.1~2.9%, Cu 1.2~2.0%, Fe 0.2~0.5%, impurities less than or equal to 0.4%, and the remainder being Al; The composition of copper alloys, by mass percentage, includes: Mg 0.05~0.3%, Cr 0.2~1.0%, Zr 0.03~0.25%, impurities less than or equal to 0.25%, and the remainder being Cu.

4. The method for rapidly obtaining the dynamic mechanical properties of the deposition layer on the surface of an electromagnetic launch track according to claim 3, characterized in that: Using arc spraying technology, the track material is used as the substrate and the armature material is used as the spraying material. A spraying layer with a thickness that meets the requirements of dynamic mechanical performance testing is sprayed onto the track substrate material. The spraying process uses a voltage of 10-60 V, a current of 50-200 A, an air pressure of 0.2-0.6 MPa, and a wire feeding rate of 2-15 mm / s.

5. The method for rapidly obtaining the dynamic mechanical properties of the deposition layer on the surface of an electromagnetic launch track according to claim 4, characterized in that: When the armature is made of aluminum alloy and the track is made of copper alloy, an arc spraying technique is used, with the track material as the substrate and the armature material as the spraying material. A coating layer with a thickness that meets the requirements for dynamic mechanical performance testing is sprayed onto the track substrate material. The preferred voltage is 20-40 V, the preferred current is 100-150 A, the preferred air pressure is 0.3-0.5 MPa, and the preferred wire feed rate is 6-10 mm / s.

6. The method for rapidly obtaining the dynamic mechanical properties of the deposition layer on the surface of an electromagnetic launch track according to claim 4, characterized in that: When using arc spraying technology, control the operating parameters of the spray gun nozzle, including a moving speed of 500 mm / s, 15-30 spray passes, and a coating thickness of 1-2 mm.

7. The method for rapidly obtaining the dynamic mechanical properties of the deposition layer on the surface of an electromagnetic launch track according to claim 1, characterized in that: When the armature is made of aluminum alloy and the track is made of copper alloy, the pulse current flows from the armature material coating layer to the track substrate material layer. The power supply is set to a current intensity of 500-1200 A, corresponding to a current density of 2000-4800 A / cm². 2 The pulse current processing time is 5-30 minutes.

8. The method for rapidly obtaining the dynamic mechanical properties of the deposition layer on the surface of an electromagnetic launch track according to claim 7, characterized in that: A current intensity of 700-1000 A corresponds to a current density of 2800-4000 A / cm². 2 .

9. The method for rapidly obtaining the dynamic mechanical properties of the deposition layer on the surface of an electromagnetic launch track according to claim 1, characterized in that: When the armature is made of aluminum alloy and the track is made of copper alloy, the heat treatment temperature is 300-600℃ and the time is 1-8 h.

10. The method for rapidly obtaining the dynamic mechanical properties of the deposition layer on the surface of an electromagnetic launch track according to claim 9, characterized in that: The heat treatment temperature is 400-500℃, and the time is 2-6 h.

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