A Comprehensive Method for Improving the Mechanical and Electrical Properties of Chromium-Zirconium-Copper Alloys by Laser Selective Melting

Abstract

This invention relates to a method for comprehensively improving the mechanical and electrical properties of laser selective melting forming of chromium-zirconium-copper alloy, belonging to the field of additive manufacturing technology. The method involves fabricating chromium-zirconium-copper components from chromium-zirconium-copper alloy powder using laser selective melting forming; cleaning the powder from the laser selective melting forming components; placing the chromium-zirconium-copper components in a heat treatment furnace, evacuating the furnace, and filling it with an inert protective gas; heating the heat treatment furnace to a set temperature and holding it for a set time; then cooling the chromium-zirconium-copper components with the furnace, thus completing the performance improvement. This invention achieves synergistic control of the strength and conductivity of laser selective melting forming of chromium-zirconium-copper alloy by controlling forming process parameters and subsequent heat treatment processes, meeting the strength and conductivity requirements of complex chromium-zirconium-copper cavity integral components such as the copper inner wall of rocket engine thrust chambers and electronic commutators.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing technology and relates to a method for comprehensively improving the mechanical and electrical properties of chromium-zirconium-copper alloys formed by laser selective melting. Background Technology

[0002] Chromium-zirconium-copper alloy (CZ / C) is a copper material with good strength, electrical and thermal conductivity, wear resistance, and oxidation resistance. It is widely used in rocket engine thrust chamber walls, motor commutators, and other parts requiring high-temperature strength, electrical and thermal conductivity. Selective laser melting (SLM) is an additive manufacturing technology based on the principle of discrete superposition, applicable to the integral manufacturing of complex internal cavity parts. Using SLM to prepare CZ / C alloy parts enables the integral forming of complex internal cavities and curved surface structures such as the regenerative cooling inner walls of rocket engine thrust chambers, motor commutators, and radiators, shortening the manufacturing cycle and the number of finished products. However, the strength and conductivity of CZ / C alloys produced by SLM are relatively low, with yield strength typically between 180-210 MPa and conductivity between 30-35% IACS. This cannot meet the product requirements for high strength and high conductivity. Summary of the Invention

[0003] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose a method for comprehensively improving the mechanical and electrical properties of laser selective melting forming of chromium-zirconium-copper alloy. By using the control of forming process parameters and subsequent heat treatment process, the strength and conductivity of laser selective melting forming of chromium-zirconium-copper alloy can be synergistically controlled, so as to meet the strength and conductivity requirements of complex chromium-zirconium-copper cavity integral components such as the copper inner wall of rocket engine thrust chamber and electronic commutator.

[0004] The solution of the present invention is:

[0005] A method for comprehensively improving the mechanical and electrical properties of laser selective melting forming of chromium-zirconium-copper alloys includes:

[0006] Chromium-zirconium-copper alloy powder is used to produce chromium-zirconium-copper components using a laser selective melting forming process.

[0007] Powder cleaning is performed on the chromium-zirconium-copper components formed by selective laser melting.

[0008] The chromium-zirconium-copper components are placed in a heat treatment furnace, evacuated, and filled with inert protective gas.

[0009] The heat treatment furnace is heated to the set temperature and held at that temperature for the set time. Then, the chromium-zirconium-copper components are cooled with the furnace, thus completing the performance improvement.

[0010] In the aforementioned method for comprehensively improving the mechanical and electrical properties of chromium-zirconium-copper alloy formed by laser selective melting, the chemical composition of the chromium-zirconium-copper alloy powder includes:

[0011] Cr: 0.2-0.6 wt.%;

[0012] Zr: 0.03-0.18 wt.%;

[0013] Impurity element O < 0.1 wt.%;

[0014] Fe ≤ 0.08 wt.%;

[0015] Si ≤ 0.1 wt.%;

[0016] The remaining elements are Cu;

[0017] The particle size of the chromium-zirconium-copper alloy powder is 15-53 μm.

[0018] In the aforementioned method for comprehensively improving the mechanical and electrical properties of chromium-zirconium-copper alloys through selective laser melting, when fabricating chromium-zirconium-copper components, the volume energy density E is used as a parameter to measure the density of the chromium-zirconium-copper components. When the volume energy density E is between 300-460 J / mm², the desired density is achieved. 3 When the density of the chromium-zirconium copper component reaches 99.9% or higher, the manufactured chromium-zirconium copper component is considered qualified.

[0019] In the aforementioned method for comprehensively improving the mechanical and electrical properties of laser selective melting forming of chromium-zirconium-copper alloys, the formula for calculating the volume energy density E is:

[0020]

[0021] In the formula, P is the laser power;

[0022] h is the scan line spacing;

[0023] v represents the scanning speed;

[0024] t represents the layer thickness.

[0025] In the aforementioned method for comprehensively improving the mechanical and electrical properties of chromium-zirconium-copper alloys through selective laser melting, the laser power P ranges from 400 to 800 W; the scanning line spacing h ranges from 0.08 to 0.16 mm; the scanning speed v ranges from 800 to 1500 mm / s; and the layer thickness t ranges from 30 to 80 μm. When fabricating chromium-zirconium-copper components, by adjusting these four parameters, the volume energy density E can be achieved at 300-460 J / mm². 3 Within the range.

[0026] In the above-mentioned method for comprehensively improving the mechanical and electrical properties of laser selective melting forming of chromium-zirconium-copper alloy, when cleaning the powder of the chromium-zirconium-copper component, if the chromium-zirconium-copper component has an internal cavity, the internal cavity is purged with compressed air in combination with a high-frequency vibration process to ensure that there is no residual powder in the internal cavity.

[0027] In the aforementioned method for comprehensively improving the mechanical and electrical properties of chromium-zirconium-copper alloys through selective laser melting, the pressure in the heat treatment furnace after vacuuming should not exceed 6.7 × 10⁻⁶. -2 Pa; the inert protective gas is argon, and the argon gas concentration is not less than 99.99%; the temperature difference of the effective heating zone of the heat treatment furnace is not greater than ±5℃.

[0028] In the above-mentioned method for comprehensively improving the mechanical and electrical properties of chromium-zirconium-copper alloy by selective laser melting, when the chromium-zirconium-copper component does not have an internal cavity, a well-sealed air resistance furnace is used for the heat treatment.

[0029] In the above-mentioned method for comprehensively improving the mechanical and electrical properties of chromium-zirconium-copper alloy by selective laser melting, the heating rate of the heat treatment furnace should not exceed 5℃ / minute; the set temperature should be 400-550℃; and the holding time should be 3-7 hours.

[0030] The aforementioned method for comprehensively improving the mechanical and electrical properties of laser selective melting forming of chromium-zirconium-copper alloys results in improved tensile strength greater than 400 MPa, yield strength greater than 340 MPa, elongation greater than 20%, and room temperature conductivity greater than 80% IACS for chromium-zirconium-copper components. This meets the strength and conductivity requirements of the copper inner wall of rocket engine thrust chambers and the integral chromium-zirconium-copper complex cavity components of electronic commutators.

[0031] The beneficial effects of this invention compared to the prior art are:

[0032] (1) This invention achieves synergistic regulation of the mechanical and electrical properties of laser selective melting formed chromium zirconium copper components by controlling the position of Cr precipitates through single-stage heat treatment.

[0033] (2) Compared with the existing heat treatment system for forgings, the present invention proposes a single aging system that can achieve a dispersed distribution of Cr-containing precipitates, which is beneficial to improving mechanical properties;

[0034] (3) The chromium zirconium copper regulated by the present invention has a tensile strength greater than 400 MPa, a yield strength greater than 340 MPa, an elongation greater than 20%, and a room temperature conductivity greater than 80% IACS. Attached Figure Description

[0035] Figure 1 This is a flowchart illustrating the comprehensive improvement of the mechanical and electrical properties of the chromium-zirconium-copper alloy of the present invention. Detailed Implementation

[0036] The present invention will be further described below with reference to the embodiments.

[0037] This invention proposes a method for comprehensively improving the mechanical and electrical properties of laser selective melting forming of chromium-zirconium-copper alloys. By controlling process parameters and heat treatment processes, the mechanical properties and electrical conductivity of laser selective melting forming of chromium-zirconium-copper alloys can be comprehensively controlled. This method can achieve a tensile strength greater than 400 MPa, a yield strength greater than 340 MPa, an elongation greater than 20%, and a room temperature electrical conductivity greater than 80% IACS, meeting the strength and electrical conductivity requirements of complex chromium-zirconium-copper cavity integral components such as the copper inner wall of rocket engine thrust chambers and electronic commutators.

[0038] A method for comprehensively improving the mechanical and electrical properties of laser selective melting forming of chromium-zirconium-copper alloys, such as... Figure 1 As shown, the specific steps include the following:

[0039] Step 1: Chromium-zirconium-copper alloy powder is processed into chromium-zirconium-copper components using a laser selective melting forming process.

[0040] The chemical composition of chromium-zirconium-copper alloy powder includes:

[0041] Cr: 0.2-0.6 wt.%;

[0042] Zr: 0.03-0.18 wt.%;

[0043] Impurity element O < 0.1 wt.%;

[0044] Fe ≤ 0.08 wt.%;

[0045] Si ≤ 0.1 wt.%;

[0046] The remaining elements are Cu;

[0047] The particle size of the chromium-zirconium-copper alloy powder is 15-53 μm.

[0048] When fabricating chromium-zirconium-copper components, the volume energy density E is used as a parameter to measure the compactness of the chromium-zirconium-copper components. When the volume energy density E is between 300-460 J / mm², the compactness is achieved. 3 When the density of a chromium-zirconium copper component reaches 99.9% or higher, the manufactured chromium-zirconium copper component is considered qualified. The formula for calculating the bulk energy density E is:

[0049]

[0050] In the formula, P is the laser power;

[0051] h is the scan line spacing;

[0052] v represents the scanning speed;

[0053] t represents the layer thickness.

[0054] In this invention, the laser power P ranges from 400 to 800 W; the scanning line spacing h ranges from 0.08 to 0.16 mm; the scanning speed v ranges from 800 to 1500 mm / s; and the layer thickness t ranges from 30 to 80 μm. When fabricating chromium-zirconium-copper components, the volume energy density E is achieved at 300-460 J / mm² by adjusting the above four parameters. 3 Within the range.

[0055] Step 2: Clean the powder from the chromium-zirconium-copper components after laser selective melting and forming.

[0056] It should be noted that when cleaning powder from chromium-zirconium-copper components, if the components have internal cavities, compressed air should be used in conjunction with high-frequency vibration to ensure that no residual powder remains in the cavities.

[0057] Step 3: Place the chromium-zirconium-copper component into a heat treatment furnace, evacuate the furnace, and fill it with an inert protective gas.

[0058] After vacuuming, the pressure in the heat treatment furnace shall not exceed 6.7 × 10⁻⁶. -2 Pa; the inert protective gas is argon, with an argon gas concentration of not less than 99.99%; the effective heating zone temperature difference of the heat treatment furnace is not greater than ±5℃. When the chromium-zirconium-copper component does not have an internal cavity, a well-sealed air resistance furnace is used for the heat treatment.

[0059] Step 4: The heat treatment furnace is heated to the set temperature and held for the set time. Then, the chromium-zirconium copper component is cooled with the furnace to complete the performance improvement.

[0060] The heating rate of the heat treatment furnace shall not exceed 5℃ / minute; the set temperature shall be 400-550℃; and the holding time shall be 3-7 hours.

[0061] After performance improvements, the chromium-zirconium-copper components exhibit a tensile strength greater than 400 MPa, a yield strength greater than 340 MPa, an elongation greater than 20%, and a room-temperature conductivity greater than 80% IACS. This meets the strength and conductivity requirements of the copper inner wall of rocket engine thrust chambers and the complex chromium-zirconium-copper integral components of electronic commutators. In addition to good mechanical properties, they also possess good electrical and thermal conductivity, ensuring that the performance of the components meets the requirements of the service environment.

[0062] After forming, chromium-zirconium copper parts undergo a single aging treatment. The heat treatment is typically performed in a vacuum furnace or an inert gas-protected furnace. If the part has no internal cavity structure, an electric furnace can also be used for heat treatment. Unlike forged chromium-zirconium copper, which uses a solution-aging process, chromium-zirconium copper parts prepared using laser selective melting (SDM) are subjected to a single aging process due to the extremely high cooling rate during forming. Cr and Zr are in a supersaturated solution state in Cu, therefore, the aging temperature is 400-550℃, and the holding time is generally 3-7 hours.

[0063] This invention provides a method for comprehensively controlling the mechanical and electrical properties of laser selective melting (LSM) chromium-zirconium-copper alloys. This method achieves synergistic control of the mechanical and electrical properties of LSM components by controlling the position of Cr precipitates through a single-stage heat treatment. Compared with existing forging heat treatment processes, this invention proposes a single-aging process that achieves a dispersed distribution of Cr-containing precipitates, which is beneficial for improving mechanical properties. The controlled LSM chromium-zirconium-copper exhibits a tensile strength greater than 400 MPa, a yield strength greater than 340 MPa, an elongation greater than 20%, and a room temperature electrical conductivity greater than 80% IACS.

[0064] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A method for comprehensively improving the mechanical and electrical properties of chromium-zirconium-copper alloys formed by laser selective melting, characterized in that: include: Chromium-zirconium-copper alloy powder is used to produce chromium-zirconium-copper components using a laser selective melting forming process. The chemical composition of the chromium-zirconium-copper alloy powder includes: Cr: 0.2-0.6 wt.%; Zr: 0.03-0.18 wt.%; Impurity element O < 0.1 wt.%; Fe ≤ 0.08 wt.%; Si≤0.1wt.%; The remaining elements are Cu; The particle size of the chromium-zirconium-copper alloy powder is 15-53. ; When manufacturing chromium-zirconium-copper components, the volume energy density is considered. As a parameter for measuring the density of chromium-zirconium-copper components, when the volume energy density... In 300-460 When the density of the chromium-zirconium copper component reaches 99.9% or higher, the manufactured chromium-zirconium copper component is considered qualified. Body energy density The calculation formula is: In the formula, Laser power; This refers to the scan line spacing; For scanning speed; For layer thickness; laser power The range is 400-800W; scan line spacing The range is 0.08-0.16 mm; scanning speed The range is 800-1500 mm / s; layer thickness The range is 30-80 When fabricating chromium-zirconium-copper components, the volume energy density is achieved by adjusting the above four parameters. In 300-460 Within the range; Powder cleaning is performed on the chromium-zirconium-copper components formed by selective laser melting. When cleaning powder from chromium-zirconium-copper components, if there is an internal cavity in the chromium-zirconium-copper component, compressed air blowing combined with high-frequency vibration process is used to remove powder from the internal cavity to ensure that there is no residual powder in the internal cavity. The chromium-zirconium-copper components are placed in a heat treatment furnace, evacuated, and filled with inert protective gas. After vacuuming, the pressure in the heat treatment furnace shall not exceed [a certain value]. The inert protective gas used is argon, with an argon gas concentration of not less than 99.99%; the temperature difference in the effective heating zone of the heat treatment furnace is not greater than [missing value]. 5℃; When there is no internal cavity inside the chromium-zirconium-copper component, a well-sealed air resistance furnace is used for the heat treatment. The heat treatment furnace is heated to the set temperature and held at that temperature for the set time. Then, the chromium-zirconium-copper components are cooled with the furnace, thus completing the performance improvement. The heating rate of the heat treatment furnace shall not exceed 5℃ / minute; the set temperature shall be 400-550℃; and the holding time shall be 3-7 hours. After performance improvement, the tensile strength of the chromium-zirconium copper component is greater than 400 MPa, the yield strength is greater than 340 MPa, the elongation is greater than 20%, and the room temperature conductivity is greater than 80% IACS; meeting the strength and conductivity requirements of the copper inner wall of the rocket engine thrust chamber and the chromium-zirconium copper complex cavity integral component of the electronic commutator.

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