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CN-121992256-A - Heat-resistant creep-resistant aluminum alloy wire and preparation method thereof

CN121992256ACN 121992256 ACN121992256 ACN 121992256ACN-121992256-A

Abstract

The invention discloses a heat-resistant creep-resistant aluminum alloy wire and a preparation method thereof, and belongs to the field of preparation of aluminum alloy conductive cable materials. The aluminum alloy wire comprises, by mass, 0.25-0.75% of Fe, 0.25-0.75% of Ni, 0.2-1% of Me, and the balance of aluminum and unavoidable impurities, wherein Me consists of La, nd, sc, zr and Ce. According to the invention, fe and Ni with fixed proportion are introduced into an aluminum matrix, meanwhile, mixed rare earth elements, sc and Zr with specific types are introduced, and the technology of large-strain extrusion, multi-pass continuous drawing and deep cooling treatment combined with continuous heat treatment is utilized, so that various nano-scale precipitated phases are precipitated inside aluminum matrix grains and micron-scale dispersion strengthening phases are formed at grain boundaries, and the strength, the extensibility, the conductivity and the creep resistance of the aluminum alloy wire are cooperatively improved by the multi-scale multi-type alloy phases.

Inventors

  • YU KUN
  • LIU MINGZHAO
  • DUAN XIAOYU

Assignees

  • 中南大学
  • 湖南省中大特冶新材料研究院有限公司
  • 长沙镁捷新材料科技有限公司

Dates

Publication Date
20260508
Application Date
20260409

Claims (10)

  1. 1. The heat-resistant creep-resistant aluminum alloy wire is characterized by comprising, by mass, 0.25-0.75% of Fe, 0.25-0.75% of Ni, 0.2-1% of Me and the balance of aluminum and unavoidable impurities; The Me comprises, by mass, 20-25% of La, 10-15% of Nd, 3-5% of Sc, 3-5% of Zr and the balance of Ce; Wherein the ratio of Fe to Ni is 1 (1-1.05), and the ratio of Sc to Zr is 1 (1-1.05); the aluminum alloy wire contains a nano Al 11 Ce 3 precipitated phase, a nano Al 11 La 3 precipitated phase, a nano Al 11 Nd 3 precipitated phase, a nano Al 3 (Sc, zr) precipitated phase and a micro Al 9 (Fe, ni) dispersed phase, wherein the nano Al 3 (Sc, zr) precipitated phase and the aluminum matrix are coherent.
  2. 2. The heat-resistant creep-resistant aluminum alloy wire according to claim 1, wherein the composition comprises, by mass, 0.5 to 0.6% of Fe, 0.5 to 0.6% of Ni, 0.6 to 1% of Me, and the balance of aluminum and unavoidable impurities.
  3. 3. A heat-resistant creep-resistant aluminum alloy wire according to claim 1 or 2, wherein the micrometer-sized Al 9 (Fe, ni) dispersed phase is distributed on grain boundaries of an aluminum alloy matrix.
  4. 4. A method for preparing the heat-resistant creep-resistant aluminum alloy wire according to any one of claims 1 to 3, comprising the following steps: S1, weighing raw materials of all components according to the designed proportion of the components of the aluminum alloy wire, melting all the raw materials, adding a refining agent for refining and degassing after all the raw materials are melted, and obtaining an aluminum alloy melt; s2, regulating the temperature of the aluminum alloy melt to 700-720 ℃, and casting to obtain an aluminum alloy cast ingot; S3, sequentially performing heat treatment, hot extrusion plastic deformation with the extrusion ratio more than or equal to 30 and first sub-zero treatment on the aluminum alloy cast ingot to obtain an aluminum alloy round rod; and S4, continuously drawing the aluminum alloy round rod at room temperature for multiple times, performing secondary cryogenic treatment and continuous heat treatment on the obtained wire, and cooling to obtain the aluminum alloy wire.
  5. 5. The method for preparing the heat-resistant creep-resistant aluminum alloy wire according to claim 4, wherein the raw materials comprise aluminum ingots, al-Fe intermediate alloy, al-Ni intermediate alloy and Al-Me intermediate alloy with purity of more than or equal to 99.9%, and the aluminum ingots are heated to 730-750 ℃ to be melted in the melting process, and then the Al-Fe intermediate alloy, the Al-Ni intermediate alloy and the Al-Me intermediate alloy are sequentially added to be melted.
  6. 6. The method for preparing a heat-resistant creep-resistant aluminum alloy wire according to claim 4, wherein the heat treatment is performed by firstly preserving heat at 480-500 ℃ for 4-6 hours, and then raising the temperature to 520-530 ℃ for 4-6 hours.
  7. 7. The method for manufacturing a heat-resistant creep-resistant aluminum alloy wire according to claim 5 or 6, wherein: the temperature of the hot extrusion plastic deformation is 400-420 ℃, and the preheating time is 1-1.5 h; The diameter of the aluminum alloy round rod is 6-10 mm.
  8. 8. The method for preparing a heat-resistant creep-resistant aluminum alloy wire according to claim 7, wherein the temperature of the first cryogenic treatment is less than or equal to-196 ℃ for 0.5-2 hours, and the temperature is raised to room temperature after the first cryogenic treatment is completed.
  9. 9. The method for manufacturing a heat-resistant creep-resistant aluminum alloy wire according to claim 4, wherein: The single-pass deformation amount of the multi-pass continuous drawing is 20-30%, the total deformation amount is more than 80%, the temperature of the second sub-cooling treatment is less than or equal to minus 196 ℃ for 0.5-2 h, and the temperature is raised to the room temperature after the second sub-cooling treatment is completed; The temperature of the continuous heat treatment control tube furnace is 475-500 ℃, and the residence time in the tube furnace is 15-60 s; the cooling mode is air cooling or water cooling.
  10. 10. The method for manufacturing a heat-resistant creep-resistant aluminum alloy wire according to claim 9, wherein the multi-pass continuous drawing process is performed with a sub-zero treatment between passes.

Description

Heat-resistant creep-resistant aluminum alloy wire and preparation method thereof Technical Field The invention belongs to the technical field of aluminum alloy conductive cable material preparation, and relates to a heat-resistant creep-resistant aluminum alloy wire and a preparation method thereof. Background In face of urgent requirements of construction of great infrastructures such as ultra-high voltage transmission and high-speed railways, aluminum alloy conductive cables are light, resource-independent and controllable and good in comprehensive performance, and become the cable materials with the most promising copper wire conservation effect. However, the development core is limited by the difficulty of balancing the strength and conductivity properties of the aluminum alloy material itself. In order to improve the mechanical strength and heat resistance of an aluminum alloy cable, alloy elements causing lattice distortion of an aluminum matrix and increasing the content of solute atoms are added to lead the conductive performance of the aluminum alloy cable to be drastically reduced, so that the contradiction between two key performances of strength and conductivity is caused. At present, a method for improving the performance of an aluminum alloy cable in a certain aspect is reported, for example, chinese patent application CN108893660A discloses a high-conductivity aluminum alloy wire and a preparation process thereof, the aluminum alloy wire improves the conductivity by adding various alloying elements such as Mg, si, cu and rare earth elements, the preparation process carries out a plurality of procedures such as vacuum melting, element addition, component detection, casting, rolling, heat treatment, wiredrawing and the like on the aluminum alloy, the conductivity of the aluminum alloy conductive cable material is up to 62.1 percent IACS, the alloy strength is up to 175MPa, but the elongation rate is only 5.1 percent. In addition, the related patents of aluminum alloy wires with excellent comprehensive performance also maintain higher heat, for example, chinese patent application CN121467690A discloses a high-modulus high-conductivity heat-resistant aluminum alloy material, an aluminum wire, a preparation method and a power transmission cable, and the grain structure is refined by adopting hot extrusion, continuous rolling, drawing and surface treatment of multistage plastic processing and through dynamic recrystallization effect in the processing process. Chinese patent application CN 118531244a discloses an aluminum alloy wire, a method for preparing the same and application thereof, wherein Si, fe, mg, zr, cu and Cr are doped in aluminum, and hot drawing, cold drawing and cryogenic treatment are combined simultaneously to improve the uniformity and compactness of the material. The aluminum alloy wire obtained by the method has good strength and conductivity, but has poor elongation and no heat resistance and creep resistance. However, with the continuous improvement of the comprehensive performance requirements of the aluminum alloy wire on physical properties, mechanical properties and the like of materials in the application process in the power industry, the aluminum alloy wire is highly required to have better mechanical strength while ensuring the physical properties of high conductivity, and particularly has excellent creep resistance under the action of high temperature and low stress for a long time. Disclosure of Invention Aiming at the problems in the prior art, the first object of the invention is to provide a heat-resistant creep-resistant aluminum alloy wire, which is characterized in that Fe and Ni with fixed proportion are introduced into a matrix, and meanwhile, rare earth elements and Zr elements with specific types are introduced, so that various nano-scale precipitated phases and micro-scale dispersion strengthening phases are formed in the grain boundary and the crystal inside of the matrix, and finally, the strength, the conductivity, the elongation and the creep resistance of the aluminum alloy wire are synergistically improved. The second object of the present invention is to provide a method for preparing a heat-resistant creep-resistant aluminum alloy wire, which uses large strain extrusion and multi-pass continuous drawing to fully crush grains and coarse second phases inside an aluminum alloy matrix, so that fine micro-scale dispersion strengthening phases Al 9 (Fe, ni) are distributed at grain boundaries to resist high-temperature creep, and nano-scale rare earth-containing second phases precipitated inside aluminum matrix grains are cooperated with cryogenic treatment and continuous heat treatment to realize stabilizing microstructure inside the aluminum alloy, guiding precipitation sequences of the alloy second phases, reducing lattice distortion, improving mechanical properties of the aluminum alloy wire, and maintaining high conductivity. The invention provide