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CN-122013006-A - High-conductivity ultrahigh-strength aluminum alloy material for aviation and preparation method thereof

CN122013006ACN 122013006 ACN122013006 ACN 122013006ACN-122013006-A

Abstract

The invention belongs to the technical field of aviation materials, and particularly relates to an aviation high-conductivity ultrahigh-strength aluminum alloy material and a preparation method thereof. The invention forms coherent Al3 (Zr, er, Y) nano dispersed phase through the synergistic effect of Zr-Er-Y multi-element microalloying, obviously refines crystal grains and inhibits recrystallization, and simultaneously, Y element optimizes the crystal boundary precipitation phase morphology, improves the crystal boundary binding force and lays a tissue foundation for alloy high toughness. The technology adopts a cooperative treatment strategy of isothermal forging, water quenching and two-stage aging, and the forging and pressing introduce high-density dislocation, and the water quenching freezes dislocation configuration to keep deformation energy storage. The two-stage aging promotes the precipitation phases to be uniformly dispersed, so that the high-efficiency superposition of deformation strengthening and precipitation strengthening is realized, and the strength and fatigue resistance are obviously improved. The final alloy realizes synchronous promotion of strength, conductivity and fatigue limit while maintaining high plasticity, effectively breaks through the bottleneck of the mutual restriction of strength and corrosion resistance, and meets the harsh requirements of aerospace on high-strength high-conductivity high-fatigue materials.

Inventors

  • ZHONG WEIGANG
  • ZHONG KUN
  • SHEN XIAOJUN

Assignees

  • 润铸电气科技(莱州)有限公司

Dates

Publication Date
20260512
Application Date
20260311

Claims (10)

  1. 1. The high-conductivity ultrahigh-strength aluminum alloy material for aviation is characterized in that Al is used as a matrix, and the chemical components of the material comprise ：Zn 6~7%、Mg 2.2~2.8%、Cu 1.3~1.7%、Zr 0.18~0.3%、Er 0.1~0.2%、Y 0.06~0.12%、Ti 0.02~0.05%、B 0.001~0.003%, percent of Al and unavoidable impurities in percentage by mass; wherein Fe is less than or equal to 0.05 percent, si is less than or equal to 0.05 percent, single impurity is less than or equal to 0.03 percent, and total impurity amount is less than or equal to 0.12 percent.
  2. 2. The high-conductivity ultrahigh-strength aluminum alloy material for aviation according to claim 1, wherein after two-stage homogenization and two-stage aging, zr and Er form coherent/semi-coherent Al 3 (Er, zr) composite nano precipitated phases, and Y elements are biased to grain boundaries and phase boundaries.
  3. 3. A method for preparing the high-conductivity ultrahigh-strength aluminum alloy material for aviation according to claim 1, which comprises the following steps: S1, pretreatment of raw materials: Selecting industrial pure aluminum ingot, zn ingot, mg ingot, cu ingot and Al-Zr, al-Er, al-Y, al-Ti-B intermediate alloy with purity more than or equal to 99.95%, polishing the surface and drying for standby; S2, smelting and purifying: Heating an aluminum ingot to 740-760 ℃ for melting, sequentially adding a Zn ingot and a Cu ingot, and preserving heat for 20-30 min; Cooling to 720-730 ℃, adding Mg ingot, and stirring for 5-10 min; Adding Al-Zr, al-Er and Al-Y, al-Ti-B intermediate alloy, and stirring for 15-20 min; Introducing high-purity argon (the purity is more than or equal to 99.99%), blowing the high-purity argon into the melt at a blowing flow rate of 0.3-0.5m 3 /h, blowing and refining for 25-30 min, adding a refining agent, standing for 15-20 min, and slagging off to obtain a pure melt; s3, semi-continuous casting: Adjusting the temperature of the melt to 690-710 ℃ and adopting semi-continuous casting to obtain an aluminum alloy cast ingot; s4, homogenizing: adopting a two-stage homogenizing process, and cooling to room temperature by water mist after homogenizing; S5, isothermal forging pretreatment: Heating the homogenized cast ingot to 380-420 ℃, preserving heat for 1-2 hours, adopting isothermal forging, and immediately quenching the cast ingot to room temperature to freeze dislocation; s6, hot extrusion forming: heating the forging stock to 450-470 ℃, preserving heat for 1-3 hours, adopting an extruder to carry out hot extrusion, and carrying out air cooling after extrusion; s7, double-stage aging treatment: and (5) performing two-stage aging treatment, and performing air cooling to room temperature after aging.
  4. 4. The preparation method of claim 3, wherein in the step S2, the components and the corresponding weight percentages of the refining agent are 40-50% of KCl, 20-30% of MgCl 2 -10% of KF, and the balance of NaCl, and the addition amount is 0.1-0.2% of the mass of the melt.
  5. 5. The method according to claim 3, wherein the semi-continuous casting in step S3 is performed at a casting speed of 80-120 mm/min, a cooling water temperature of 20-30 ℃ and a cooling strength of 15-20 ℃.
  6. 6. The preparation method according to claim 3, wherein the two-stage homogenizing process in the step S4 is characterized in that the first stage is performed at 400-420 ℃ for 4-6 hours, and the second stage is performed at 480-500 ℃ for 8-10 hours.
  7. 7. The method according to claim 3, wherein the water mist cooling rate in step S4 is 35-45 ℃ per minute.
  8. 8. The method of claim 3, wherein the deformation rate is controlled to 10-20% and the deformation speed is controlled to 2-5 mm/S during the isothermal forging in the step S5.
  9. 9. The method of claim 3, wherein the extrusion ratio is controlled to be (20-30) 1, the extrusion speed is 5-10 mm/S, and the die temperature is 400-420 ℃ during the hot extrusion of the extruder in the step S6.
  10. 10. The preparation method according to claim 3, wherein the two-stage aging treatment in the step S7 is specifically that the first-stage aging is carried out at 100-110 ℃ for 4-6 hours, and the second-stage aging is carried out at 160-170 ℃ for 8-12 hours.

Description

High-conductivity ultrahigh-strength aluminum alloy material for aviation and preparation method thereof Technical Field The invention belongs to the technical field of aviation materials, and particularly relates to an aviation high-conductivity ultrahigh-strength aluminum alloy material and a preparation method thereof. Background The aluminum alloy has high specific strength, excellent processability and good corrosion resistance, and is an irreplaceable core structural material in the fields of aerospace, transportation and the like. Among them, 7XXX series (Al-Zn-Mg-Cu) aluminum alloys have been the mainstream choice for lightweight construction for aviation due to their ultra-high strength since the advent of the 7075 alloy in the 40 th century. The development history of 7XXX series aluminum alloys is essentially a process of continuously pursuing a synergistic improvement in strength, toughness and corrosion resistance, and is roughly divided into four stages: the first generation, represented by 7075-T6 alloy, obtained high strength by peak aging treatment, but had a severe tendency to Stress Corrosion Cracking (SCC). And in the second generation, overaging processes such as T73, T76 and the like are developed, and the stress corrosion resistance is obviously improved at the cost of a small amount of strength. The third generation is to reduce the impurity content of Fe and Si, introduce Zr element to replace Cr, and research and develop 7050, 7475 and other alloys. The Al 3 Zr dispersion phase formed by Zr can inhibit recrystallization and refine grains, greatly improves hardenability and fracture toughness, and is a major technical breakthrough of the system. And in the fourth generation, the 7055-T77 alloy is developed by improving the Zn content and combining with complex thermomechanical treatment, the tensile strength can reach more than 600MPa, the excellent toughness is considered, and the highest level of the current aviation aluminum alloy batch application is represented. Although the above alloys have been applied on a large scale, with the improvement of the requirements of structural efficiency, reliability and life of new generation aircrafts, the existing 7XXX series alloys gradually expose the common problem that the pursuit of high strength is often accompanied by a decrease in plasticity and toughness, and the overaging treatment for improving corrosion resistance causes a loss of strength. The contradiction between strength and corrosion and toughness makes it difficult for the traditional alloy to meet the comprehensive requirements of high strength, high corrosion resistance and high fatigue life at the same time under the limit working condition. In order to break through the bottleneck microalloying technology and become a research hot spot, trace rare earth elements and transition group elements are added on the basis of Al-Zn-Mg-Cu, so that deep influence on microstructure can be generated. However, the existing researches focus on single or binary rare earth addition, and for the synergistic composite addition of three elements of Zr, er and Y and the coupling action mechanism of the synergistic composite addition and the forging deformation, the two-stage aging and other processes, no industrial technical scheme of a system is formed. Based on the above, the invention aims to develop an aluminum alloy material with high strength, high conductivity and high fatigue limit by comprehensively utilizing the synergistic advantage of Zr-Er-Y multi-element microalloying so as to meet the use requirement of new-generation aerospace equipment. Disclosure of Invention The invention aims at solving the existing problems and provides an aviation high-conductivity ultrahigh-strength aluminum alloy material and a preparation method thereof. The invention is realized by the following technical scheme: The high-conductivity ultrahigh-strength aluminum alloy material for aviation uses Al as a matrix, and comprises the following chemical components in percentage by mass, wherein the balance of ：Zn 6~7%、Mg 2.2~2.8%、Cu 1.3~1.7%、Zr 0.18~0.3%、Er 0.1~0.2%、Y 0.06~0.12%、Ti 0.02~0.05%、B 0.001~0.003%, is Al and unavoidable impurities; wherein Fe is less than or equal to 0.05 percent, si is less than or equal to 0.05 percent, single impurity is less than or equal to 0.03 percent, and total impurity amount is less than or equal to 0.12 percent. Further, after two-stage homogenization and two-stage aging, zr and Er form coherent/semi-coherent Al 3 (Er, zr) composite nano precipitated phases, and Y element is biased to grain boundaries and phase boundaries. A method of preparing the high conductivity ultra high strength aluminum alloy material for aerospace according to claim 1, comprising the steps of: S1, pretreatment of raw materials: Selecting industrial pure aluminum ingot, zn ingot, mg ingot, cu ingot and Al-Zr, al-Er, al-Y, al-Ti-B intermediate alloy with purity more than or equal to 99.95%, pol