A method for producing high strength 7xxx-series aluminum alloy wire for additive manufacturing
A method for preparing aluminum alloy wires by using specific processes and element control has solved the problems of compositional uniformity and microstructure stability of 7xxx series aluminum alloys in additive manufacturing, and has achieved the preparation of high-strength and high-conductivity aluminum alloy wires, which are suitable for aerospace and other fields.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NORTHEAST LIGHT ALLOY CO LTD
- Filing Date
- 2026-03-24
- Publication Date
- 2026-05-29
AI Technical Summary
In existing technologies, 7xxx series aluminum alloys have problems in additive manufacturing, such as difficulty in controlling compositional uniformity, poor inclusion removal, and poor microstructure refinement stability, which limits their application in welding and additive manufacturing.
High-strength aluminum alloy wires are prepared by using aluminum alloy smelting, casting, homogenization annealing, hot rolling and cold drawing processes with specific element ratios, combined with the composite refining mechanism of transition elements such as Zr and Sc. Nanoscale Al3(Sc) dispersed phases are formed through arc additive manufacturing, which promotes the formation of equiaxed crystals and grain refinement.
It has enabled the hot continuous rolling and drawing of high-strength aluminum alloy wire, reduced the tendency of hot cracking, improved the yield and applicability of additive manufacturing, and significantly improved the yield strength and elongation of arc additive parts.
Smart Images
Figure CN122105203A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of methods for preparing aluminum alloy wire. Background Technology
[0002] 7xxx series aluminum alloys (Al-Zn-Mg-Cu series) are a typical class of high-strength precipitation-strengthened aluminum alloys, possessing excellent specific strength, good fatigue resistance, and high fracture toughness, and are widely used in aerospace, transportation, and high-end equipment manufacturing. However, this series of aluminum alloys generally suffers from problems such as high hot cracking tendency, poor weldability, non-uniform microstructure, and high heat treatment sensitivity, which significantly limits their application in traditional welding and additive manufacturing fields.
[0003] In existing technologies, researchers have attempted to improve wire quality by adjusting the Zn / Mg / Cu ratio, introducing transition elements such as Zr, Sc, and Er to refine grains, employing semi-continuous casting combined with multi-stage cold drawing processes, or utilizing vacuum induction melting combined with protective gas atomization technology. However, problems such as element loss due to burning, non-uniform microstructure, low conductivity, and susceptibility to cracking in additive manufacturing still exist. In particular, achieving uniform control of composition, removal of inclusions, and refinement and stabilization of microstructure during continuous casting and rolling processes remains a key technical challenge restricting the high performance and additive manufacturing applicability of 7xxx series aluminum alloy wires.
[0004] Therefore, there is an urgent need to develop a method for preparing high-purity, high-density, and homogenized microstructure wires for additive manufacturing of 7xxx series aluminum alloys, in order to obtain wires with high strength, high conductivity, and excellent additive adaptability, providing a reliable material basis for the lightweight manufacturing of aerospace structural components. Summary of the Invention
[0005] In order to solve the technical problems of difficulty in achieving uniform control of composition, removal of inclusions and refinement and stabilization of microstructure in the continuous casting and rolling process, this invention provides a method for preparing high-strength 7xxx series aluminum alloy wire for additive manufacturing.
[0006] A method for preparing high-strength 7xxx series aluminum alloy wire for additive manufacturing, specifically comprising the following steps:
[0007] I. Smelting of aluminum alloy ingots: The ingots are smelted according to the following elemental mass percentages: Zn: 6.5~7.5%, Mg: 1.3~2.0%, Cu: 0.5~1.3%, Sc: 0.10~0.20%, Zr: 0.08~0.15%, Ti≤0.06%, Fe≤0.12%, Si≤0.08%, with the remainder being Al. The smelting temperature is 720℃~760℃, and the smelting heating time is 2h~6h. The ingots are then refined to obtain molten aluminum.
[0008] II. Casting of aluminum alloy ingots: The molten aluminum obtained in step one is cast at a casting temperature of 700℃~735℃, a casting speed of 60mm / min~100mm / min, a casting water pressure of 0.04MPa~0.07MPa, and a cooling water temperature of 15~25℃ to obtain aluminum alloy ingots with a diameter of 160~170mm.
[0009] 3. Homogenization annealing of aluminum alloy ingots: The aluminum alloy ingots obtained in step 2 are placed into a resistance heating furnace for homogenization annealing to obtain homogenized annealed ingots. The homogenization annealing temperature is 465~470℃ and the holding time is 20~30h.
[0010] IV. Sawing and Turning: The oxide scale on the surface of the homogenized annealed ingot is turned to obtain an aluminum alloy ingot with a diameter of 140mm to 150mm. Then, it is cut into a billet with a length of 3000 to 5500mm to obtain aluminum alloy rolled ingot raw material.
[0011] V. Preheating of aluminum alloy ingots: The aluminum alloy rolled ingot blanks from step four are loaded into a pusher-type resistance heating furnace and held at a temperature of 390℃~450℃ for 2h~6h to obtain preheated aluminum alloy rolled ingot blanks.
[0012] VI. Preparation of wire rod by rolling method: The preheated aluminum alloy rolled ingot is placed in a hot rolling mill for rolling. First, it is hot rolled into Φ20~30mm hot rolled bar through multiple passes of hot rough rolling, with a final rolling temperature of 300~350℃; then it is hot rolled into Φ8~12mm hot rolled wire through multiple passes of hot finish rolling, with a final rolling temperature of 360~400℃.
[0013] VII. Wire intermediate annealing: The hot-rolled wire obtained in step VI is placed in a resistance heating furnace and held at 400℃~420℃ for 2h~3h, and then cooled to obtain annealed aluminum alloy wire.
[0014] 8. Cold drawing: The annealed aluminum alloy wire is cold drawn under a deformation rate of 20% to 35%, and then the annealing and cold drawing are repeated to obtain the cold-drawn billet.
[0015] 9. The cold-drawn billet obtained in step 8 is scraped to obtain high-strength 7xxx series aluminum alloy wire for additive manufacturing, thus completing the preparation.
[0016] Furthermore, in step one, the elements are smelted according to their mass percentages: Zn: 6.8~7.5%, Mg: 1.5~2.0%, Cu: 0.8~1.3%, Sc: 0.10~0.20%, Zr: 0.08~0.15%, Ti≤0.06%, Fe≤0.10%, Si≤0.08%, and the remainder being Al.
[0017] Furthermore, the homogenization annealing process described in step three is first held at 400℃ for 5-8 hours, and then the temperature is controlled at 465-470℃ for 20-30 hours.
[0018] Furthermore, in step seven, the cooling process is controlled to have a cooling rate of 40℃ / h to 60℃ / h.
[0019] Furthermore, in step eight, the diameter of the cold-drawn blank is Φ1.2~1.6mm.
[0020] Furthermore, in step nine, the amount of wire scraped is controlled to be 0.05~0.25mm.
[0021] Furthermore, after the high-strength 7xxx series aluminum alloy wire for additive manufacturing obtained in step nine is manufactured by arc additive manufacturing, the printed part has a yield strength > 220MPa, a yield strength > 320MPa, and an elongation > 6%.
[0022] Furthermore, after solution treatment and aging, the electric arc additive parts exhibit a yield strength ≥420MPa, a tensile strength ≥520MPa, and an elongation ≥8%.
[0023] Furthermore, the solution treatment process is carried out at 465~470℃ for 2~8 hours.
[0024] Furthermore, the aging period is 115~125℃, with heat preservation for 20~30 hours.
[0025] Beneficial effects of this invention:
[0026] This invention provides a method for preparing 7xxx series aluminum alloy wire for additive manufacturing. It introduces a composite grain refinement mechanism using transition elements such as Zr and Sc, forming a nanoscale Al3(Sc) dispersed phase during the arc additive manufacturing process. This effectively promotes equiaxed crystal formation and grain refinement, thereby significantly reducing the tendency for hot cracking. This invention enables the hot continuous rolling and drawing of high-strength aluminum alloy wire for additive manufacturing, combining high yield and high efficiency, making it suitable for industrial application.
[0027] The 7xxx series aluminum alloy wire prepared by this invention is used for additive manufacturing. Attached Figure Description
[0028] Figure 1 The image shows the surface morphology of the aluminum alloy wire obtained in Example 1.
[0029] Figure 2 The image shows the metallographic structure of the aluminum alloy wire obtained in Example 1 after arc additive manufacturing.
[0030] Figure 3 This is a grain structure diagram of the aluminum alloy wire obtained in Example 1 after arc additive manufacturing;
[0031] Figure 4 The image shows the metallographic structure of the aluminum alloy wire obtained in Comparative Example 3 after arc additive manufacturing.
[0032] Figure 5 The image shows the SEM microstructure of the aluminum alloy wire obtained in Comparative Example 4 after arc additive manufacturing. Detailed Implementation
[0033] Specific Implementation Method 1: This implementation method describes a method for preparing high-strength 7xxx series aluminum alloy wire for additive manufacturing, specifically following these steps:
[0034] I. Smelting of aluminum alloy ingots: The ingots are smelted according to the following elemental mass percentages: Zn: 6.5~7.5%, Mg: 1.3~2.0%, Cu: 0.5~1.3%, Sc: 0.10~0.20%, Zr: 0.08~0.15%, Ti≤0.06%, Fe≤0.12%, Si≤0.08%, with the remainder being Al. The smelting temperature is 720℃~760℃, and the smelting heating time is 2h~6h. The ingots are then refined to obtain molten aluminum.
[0035] II. Casting of aluminum alloy ingots: The molten aluminum obtained in step one is cast at a casting temperature of 700℃~735℃, a casting speed of 60mm / min~100mm / min, a casting water pressure of 0.04MPa~0.07MPa, and a cooling water temperature of 15~25℃ to obtain aluminum alloy ingots with a diameter of 160~170mm.
[0036] 3. Homogenization annealing of aluminum alloy ingots: The aluminum alloy ingots obtained in step 2 are placed into a resistance heating furnace for homogenization annealing to obtain homogenized annealed ingots. The homogenization annealing temperature is 465~470℃ and the holding time is 20~30h.
[0037] IV. Sawing and Turning: The oxide scale on the surface of the homogenized annealed ingot is turned to obtain an aluminum alloy ingot with a diameter of 140mm to 150mm. Then, it is cut into a billet with a length of 3000 to 5500mm to obtain aluminum alloy rolled ingot raw material.
[0038] V. Preheating of aluminum alloy ingots: The aluminum alloy rolled ingot blanks from step four are loaded into a pusher-type resistance heating furnace and held at a temperature of 390℃~450℃ for 2h~6h to obtain preheated aluminum alloy rolled ingot blanks.
[0039] VI. Preparation of wire rod by rolling method: The preheated aluminum alloy rolled ingot is placed in a hot rolling mill for rolling. First, it is hot rolled into Φ20~30mm hot rolled bar through multiple passes of hot rough rolling, with a final rolling temperature of 300~350℃; then it is hot rolled into Φ8~12mm hot rolled wire through multiple passes of hot finish rolling, with a final rolling temperature of 360~400℃.
[0040] VII. Wire intermediate annealing: The hot-rolled wire obtained in step VI is placed in a resistance heating furnace and held at 400℃~420℃ for 2h~3h, and then cooled to obtain annealed aluminum alloy wire.
[0041] 8. Cold drawing: The annealed aluminum alloy wire is cold drawn under a deformation rate of 20% to 35%, and then the annealing and cold drawing are repeated to obtain the cold-drawn billet.
[0042] 9. The cold-drawn billet obtained in step 8 is scraped to obtain high-strength 7xxx series aluminum alloy wire for additive manufacturing, thus completing the preparation.
[0043] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that: Step One involves smelting the components by mass percentage: Zn: 6.8~7.5%, Mg: 1.5~2.0%, Cu: 0.8~1.3%, Sc: 0.10~0.20%, Zr: 0.08~0.15%, Ti≤0.06%, Fe≤0.10%, Si≤0.08%, with the remainder being Al. Everything else is the same as in Specific Implementation Method One.
[0044] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that: the homogenization annealing treatment in step three is first held at 400℃ for 5-8 hours, and then the temperature is controlled at 465-470℃ for 20-30 hours. Everything else is the same as in Specific Implementation Method One or Two.
[0045] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the cooling rate in step seven is controlled at 40℃ / h to 60℃ / h. Everything else is the same as in Specific Implementation Methods One to Three.
[0046] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that the diameter of the cold-drawn billet obtained in step eight is Φ1.2~1.6mm. Everything else is the same as in Specific Implementation Methods One to Four.
[0047] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that: in step nine, the amount of wire scraped is controlled to be 0.05~0.25mm. Everything else is the same as in Specific Implementation Methods One to Five.
[0048] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that: after the high-strength 7xxx series aluminum alloy wire for additive manufacturing obtained in step nine is manufactured by arc additive manufacturing, the printed part exhibits a yield strength > 220 MPa, a yield strength > 320 MPa, and an elongation > 6%. Other aspects are the same as in Specific Implementation Methods One to Six.
[0049] In this embodiment, the electric arc additive manufacturing process is controlled with a voltage of 10~12V and a current of 100~120A.
[0050] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that: after solution treatment and aging, the yield strength of the arc additive manufacturing part is ≥420MPa, the tensile strength is ≥520MPa, and the elongation is ≥8%. Everything else is the same as in Specific Implementation Methods One to Seven.
[0051] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that the solution treatment is carried out at 465~470℃ for 2~8 hours. Everything else is the same as in Specific Implementation Methods One to Eight.
[0052] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods One to Nine in that the aging process is carried out at 115~125℃ for 20~30 hours. Everything else is the same as Specific Implementation Methods One to Nine.
[0053] The scope of this invention is not limited to the above-described embodiments; a combination of one or more specific embodiments can also achieve the purpose of the invention.
[0054] Example 1
[0055] This embodiment describes a method for preparing high-strength 7xxx series aluminum alloy wire for additive manufacturing, which is carried out according to the following steps:
[0056] I. Smelting of aluminum alloy ingots: The alloys are smelted according to the following element mass percentages: Zn: 6.5%, Mg: 1.3%, Cu: 0.5%, Sc: 0.10%, Zr: 0.08%, Ti: 0.04%, Fe: 0.12%, Si: 0.08%, and the remainder is Al. The smelting temperature is 720℃ and the smelting heating time is 2 hours. Then, the alloys are refined to obtain molten aluminum.
[0057] II. Casting of aluminum alloy ingots: The aluminum liquid obtained in step one is cast at a casting temperature of 700℃, a casting speed of 60mm / min, a casting water pressure of 0.04MPa, and a cooling water temperature of 15℃ to obtain aluminum alloy ingots with a diameter of 170mm.
[0058] III. Homogenization annealing of aluminum alloy ingots: The aluminum alloy ingots obtained in step II are placed into a resistance heating furnace for homogenization annealing. First, the temperature is held at 400℃ for 5 hours, and then the homogenization annealing temperature is controlled at 465℃ for 30 hours to obtain homogenized annealed ingots.
[0059] IV. Sawing and Turning: The oxide scale on the surface of the homogenized annealed ingot is turned to obtain an aluminum alloy ingot with a diameter of 145mm. Then, it is cut into a billet with a length of 3000mm to obtain aluminum alloy rolled ingot raw material.
[0060] V. Preheating of aluminum alloy ingots: The aluminum alloy rolled ingot blanks from step four are loaded into a pusher-type resistance heating furnace and held at 390℃ for 6 hours to obtain preheated aluminum alloy rolled ingots.
[0061] VI. Preparation of wire rod by rolling method: The preheated aluminum alloy rolled ingot is placed in a hot rolling mill for rolling. First, it is hot rolled into Φ20~30mm hot rolled bar through multiple passes of hot rough rolling, with a final rolling temperature of 300~350℃; then it is hot rolled into Φ8~12mm hot rolled wire through multiple passes of hot finish rolling, with a final rolling temperature of 360~400℃.
[0062] VII. Wire intermediate annealing: The hot-rolled wire obtained in step VI is placed in a resistance heating furnace and held at 400℃ for 2 hours, and then cooled at a cooling rate of 40℃ / h to obtain annealed aluminum alloy wire.
[0063] 8. Cold drawing: The annealed aluminum alloy wire is cold drawn under a deformation rate of 20%, and then the annealing and cold drawing are repeated to obtain a cold-drawn billet with a diameter of 1.2mm.
[0064] 9. The cold-drawn billet obtained in step 8 is scraped with a scraping amount of 0.05 mm to obtain high-strength 7xxx series aluminum alloy wire for additive manufacturing, thus completing the preparation.
[0065] The high-strength 7xxx series aluminum alloy wire obtained in Example 1 was used to manufacture the arc-added part, which was dense, crack-free, and had fine equiaxed grains, with a yield strength of 223 MPa, a tensile strength of 324 MPa, and an elongation of 7.5%. After solution treatment at 465℃ for 6 hours and aging at 115℃ for 30 hours, the yield strength of the arc-added part was 425 MPa, the tensile strength was 526 MPa, and the elongation was 9.5%.
[0066] Example 2
[0067] This embodiment describes a method for preparing high-strength 7xxx series aluminum alloy wire for additive manufacturing, which is carried out according to the following steps:
[0068] I. Smelting of aluminum alloy ingots: The alloys are smelted according to the following element mass percentages: Zn: 7.5%, Mg: 2.0%, Cu: 1.3%, Sc: 0.20%, Zr: 0.15%, Ti: 0.02%, Fe: 0.10%, Si: 0.06%, and the remainder is Al. The smelting temperature is 760℃ and the smelting heating time is 6 hours. Then, the alloys are refined to obtain molten aluminum.
[0069] II. Casting of aluminum alloy ingots: The aluminum liquid obtained in step one is cast at a casting temperature of 735℃, a casting speed of 100mm / min, a casting water pressure of 0.07MPa, and a cooling water temperature of 25℃ to obtain aluminum alloy ingots with a diameter of 170mm.
[0070] III. Homogenization Annealing of Aluminum Alloy Ingots: The aluminum alloy ingots obtained in step II are placed into a resistance heating furnace for homogenization annealing. First, the temperature is held at 400℃ for 8 hours, and then the homogenization annealing temperature is controlled at 470℃ for 20 hours to obtain homogenized annealed ingots.
[0071] IV. Sawing and Turning: The oxide scale on the surface of the homogenized annealed ingot is turned to obtain an aluminum alloy ingot with a diameter of 162mm. Then, it is cut into a billet with a length of 5500mm to obtain aluminum alloy rolled ingot raw material.
[0072] V. Preheating of aluminum alloy ingots: The aluminum alloy rolled ingot blanks from step four are loaded into a pusher-type resistance heating furnace and held at 450℃ for 2 hours to obtain preheated aluminum alloy rolled ingots.
[0073] VI. Preparation of wire rod by rolling method: The preheated aluminum alloy rolled ingot is placed in a hot rolling mill for rolling. First, it is hot rolled into Φ20~30mm hot rolled bar through multiple passes of hot rough rolling, with a final rolling temperature of 300~350℃; then it is hot rolled into Φ8~12mm hot rolled wire through multiple passes of hot finish rolling, with a final rolling temperature of 360~400℃.
[0074] VII. Wire intermediate annealing: The hot-rolled wire obtained in step VI is placed in a resistance heating furnace and held at 420℃ for 3 hours, and then cooled at a cooling rate of 60℃ / h to obtain annealed aluminum alloy wire.
[0075] 8. Cold drawing: The annealed aluminum alloy wire is cold drawn under a deformation rate of 35%, and then the annealing and cold drawing are repeated to obtain a cold-drawn billet with a diameter of 1.6mm.
[0076] 9. The cold-drawn billet obtained in step 8 is scraped with a scraping amount of 0.025 mm to obtain high-strength 7xxx series aluminum alloy wire for additive manufacturing, thus completing the preparation.
[0077] After being manufactured using the high-strength 7xxx series aluminum alloy wire obtained in Example 2, the arc-manufacturing part exhibited a dense, crack-free microstructure with fine, equiaxed grains, a yield strength of 248 MPa, a tensile strength of 362 MPa, and an elongation of 6.5%. Following solution treatment at 470°C for 4 hours and aging at 125°C for 20 hours, the arc-manufacturing part showed a yield strength of 456 MPa, a tensile strength of 554 MPa, and an elongation of 8.5%.
[0078] Comparative Example 1
[0079] The difference between this comparative example and Example 1 is that in step one, the elements are smelted according to their mass percentages: Zn: 6.5%, Mg: 1.2%, Cu: 0.2%, Sc: 0.10%, Zr: 0.12%, Ti: 0.02%, Fe: 0.10%, Si: 0.06%, and the remainder being Al. Everything else is the same as in Example 1.
[0080] The aluminum alloy wire obtained in Comparative Example 1, after being manufactured by arc additive manufacturing, exhibits a dense, crack-free microstructure in its printed state, with a yield strength of 210 MPa, a tensile strength of 305 MPa, and an elongation of 8.6%. After solution treatment and aging, the arc-added part has a yield strength of 403 MPa, a tensile strength of 506 MPa, and an elongation ≥9.5%.
[0081] Comparative Example 2
[0082] The difference between this comparative example and Example 1 is that in step one, the elements are smelted according to their mass percentages: Zn: 7.6%, Mg: 2.5%, Cu: 1.8%, Sc: 0.12%, Zr: 0.10%, Ti: 0.02%, Fe: 0.10%, Si: 0.06%, and the remainder being Al. Everything else is the same as in Example 1.
[0083] The aluminum alloy wire obtained in Comparative Example 2, after being manufactured by arc additive manufacturing, exhibited a large number of coarse eutectic phases in its printed microstructure, with a yield strength of 248 MPa, a tensile strength of 340 MPa, and an elongation of 5.5%. After solution treatment and aging, the arc-added part had a yield strength of 436 MPa, a tensile strength of 538 MPa, and an elongation ≥6.5%.
[0084] Comparative Example 3
[0085] The difference between this comparative example and Example 1 is that in step one, the elements were smelted according to their mass percentages: Zn: 6.8%, Mg: 1.5%, Cu: 1.0%, Sc: 0.05%, Zr: 0.06%, Ti: 0.02%, Fe: 0.10%, Si: 0.06%, and the remainder being Al. Everything else was the same as in Example 1.
[0086] The aluminum alloy wire obtained in Comparative Example 3, after being manufactured by arc additive manufacturing, exhibited coarse grains and microcracks in its printed microstructure, with a yield strength of 205 MPa, a tensile strength of 308 MPa, and an elongation of 5.0%. After solution treatment and aging, the arc-added part had a yield strength of 408 MPa, a tensile strength of 512 MPa, and an elongation ≥6.0%.
[0087] Comparative Example 4
[0088] The difference between this comparative example and Example 1 is that in step one, the elements were smelted according to their mass percentages: Zn: 7.0%, Mg: 1.6%, Cu: 0.8%, Sc: 0.25%, Zr: 0.18%, Ti: 0.02%, Fe: 0.10%, Si: 0.06%, and the remainder being Al. Everything else was the same as in Example 1.
[0089] The aluminum alloy wire obtained in Comparative Example 4, after being manufactured by arc additive manufacturing, exhibited coarse Al3(Sc,Zr) phase particles in its printed microstructure, with a yield strength of 228 MPa, a tensile strength of 326 MPa, and an elongation of 5.3%. After solution treatment and aging, the arc-added part showed a yield strength of 416 MPa, a tensile strength of 513 MPa, and an elongation of 6.8%.
[0090] Figure 1 The image shows the surface morphology of the aluminum alloy wire obtained in Example 1; the wire surface is smooth and free of cracks.
[0091] Figure 2 The image shows the metallographic structure of the aluminum alloy wire obtained in Example 1 after arc additive manufacturing; the arc additive part has a dense structure, no cracks, and a small number of pores.
[0092] Figure 3 The image shows the grain structure of the aluminum alloy wire obtained in Example 1 after arc additive manufacturing; the microstructure of the arc additive part is composed of fine equiaxed grains.
[0093] Figure 4 The image shows the metallographic structure of the aluminum alloy wire obtained in Comparative Example 3 after arc additive manufacturing; microcracks exist in the microstructure of the arc additive part, resulting in poor printing effect.
[0094] Figure 5 The image shows the SEM microstructure of the aluminum alloy wire obtained in Comparative Example 4 after arc additive manufacturing. It can be seen that coarse Al3(Sc, Zr) phase particles exist in the printed microstructure, resulting in low elongation.
Claims
1. A method for preparing high-strength 7xxx series aluminum alloy wire for additive manufacturing, characterized in that... This method is specifically carried out in the following steps: I. Smelting of aluminum alloy ingots: The ingots are smelted according to the following elemental mass percentages: Zn: 6.5~7.5%, Mg: 1.3~2.0%, Cu: 0.5~1.3%, Sc: 0.10~0.20%, Zr: 0.08~0.15%, Ti≤0.06%, Fe≤0.12%, Si≤0.08%, with the remainder being Al. The smelting temperature is 720℃~760℃, and the smelting heating time is 2h~6h. The ingots are then refined to obtain molten aluminum. II. Casting of aluminum alloy ingots: The molten aluminum obtained in step one is cast at a casting temperature of 700℃~735℃, a casting speed of 60mm / min~100mm / min, a casting water pressure of 0.04MPa~0.07MPa, and a cooling water temperature of 15~25℃ to obtain aluminum alloy ingots with a diameter of 160~170mm.
3. Homogenization annealing of aluminum alloy ingots: The aluminum alloy ingots obtained in step 2 are placed into a resistance heating furnace for homogenization annealing to obtain homogenized annealed ingots. The homogenization annealing temperature is 465~470℃ and the holding time is 20~30h. IV. Sawing and Turning: The oxide scale on the surface of the homogenized annealed ingot is turned to obtain an aluminum alloy ingot with a diameter of 140mm to 150mm. Then, it is cut into a billet with a length of 3000 to 5500mm to obtain aluminum alloy rolled ingot raw material. V. Preheating of aluminum alloy ingots: The aluminum alloy rolled ingot blanks from step four are loaded into a pusher-type resistance heating furnace and held at a temperature of 390℃~450℃ for 2h~6h to obtain preheated aluminum alloy rolled ingot blanks. VI. Preparation of wire rod by rolling method: The preheated aluminum alloy rolled ingot is placed in a hot rolling mill for rolling. First, it is hot rolled into Φ20~30mm hot rolled bar through multiple passes of hot rough rolling, with a final rolling temperature of 300~350℃; then it is hot rolled into Φ8~12mm hot rolled wire through multiple passes of hot finish rolling, with a final rolling temperature of 360~400℃. VII. Wire intermediate annealing: The hot-rolled wire obtained in step VI is placed in a resistance heating furnace and held at 400℃~420℃ for 2h~3h, and then cooled to obtain annealed aluminum alloy wire.
8. Cold drawing: The annealed aluminum alloy wire is cold drawn under a deformation rate of 20% to 35%, and then the annealing and cold drawing are repeated to obtain the cold-drawn billet.
9. The cold-drawn billet obtained in step 8 is scraped to obtain high-strength 7xxx series aluminum alloy wire for additive manufacturing, thus completing the preparation.
2. The method for preparing high-strength 7xxx series aluminum alloy wire for additive manufacturing according to claim 1, characterized in that... Step 1 involves smelting elements with the following mass percentages: Zn: 6.8~7.5%, Mg: 1.5~2.0%, Cu: 0.8~1.3%, Sc: 0.10~0.20%, Zr: 0.08~0.15%, Ti≤0.06%, Fe≤0.10%, Si≤0.08%, and the remainder being Al.
3. The method for preparing high-strength 7xxx series aluminum alloy wire for additive manufacturing according to claim 1, characterized in that... The homogenization annealing process described in step three involves first holding the temperature at 400℃ for 5-8 hours, and then controlling the temperature at 465-470℃ for 20-30 hours.
4. The method for preparing high-strength 7xxx series aluminum alloy wire for additive manufacturing according to claim 1, characterized in that... Step 7: During the cooling process, the cooling rate is controlled to be 40℃ / h to 60℃ / h.
5. The method for preparing high-strength 7xxx series aluminum alloy wire for additive manufacturing according to claim 1, characterized in that... Step 8 yields a cold-drawn billet with a diameter of Φ1.2~1.6mm.
6. The method for preparing high-strength 7xxx series aluminum alloy wire for additive manufacturing according to claim 1, characterized in that... Step nine: Control the amount of wire scraping to be 0.05~0.25mm.
7. The method for preparing high-strength 7xxx series aluminum alloy wire for additive manufacturing according to claim 1, characterized in that... After the high-strength 7xxx series aluminum alloy wire for additive manufacturing obtained in step nine is processed by arc additive manufacturing, the printed part has a yield strength > 220MPa, a yield strength > 320MPa, and an elongation > 6%.
8. The method for preparing high-strength 7xxx series aluminum alloy wire for additive manufacturing according to claim 7, characterized in that... After solution treatment and aging, the electric arc additive parts have a yield strength ≥420MPa, tensile strength ≥520MPa, and elongation ≥8%.
9. The method for preparing a high-strength 7xxx series aluminum alloy wire for additive manufacturing according to claim 8, characterized in that... The solution treatment process is carried out at 465~470℃ for 2~8 hours.
10. The method for preparing a high-strength 7xxx series aluminum alloy wire for additive manufacturing according to claim 8, characterized in that... The aging period is 115~125℃, and the heat preservation time is 20~30h.