Layered heterogeneous regenerated aluminum alloy with self-healing function and preparation method thereof

Abstract

The invention provides a layered heterogeneous regenerated aluminum alloy with a self-healing function and a preparation method of the layered heterogeneous regenerated aluminum alloy. The layered heterogeneous secondary aluminum alloy with the self-healing function is composed of a high-strength layer and a high-toughness layer which are alternately laminated, the high-strength layer comprises Al-Ni-Cu-Mg series alloy and has a nanoscale Al3Ni precipitated phase, and the grain size is 1-3 microns; the high-toughness layer comprises an Al-Fe-Si-Zn series amorphous / nanocrystalline composite structure, and the amorphous phase accounts for 40%-50% of the Al-Fe-Si-Zn series amorphous / nanocrystalline composite structure; a Sn / In element concentration gradient transition area is formed at the interlayer interface, and the thickness of the transition area is 300-600 nm. According to the invention, a framework of alternately stacking high-strength layers (Al-Ni-Cu-Mg series) and high-toughness layers (Al-Fe-Si-Zn amorphous / nanocrystalline) is adopted, a nanoscale Al3Ni precipitated phase of the high-strength layers is used for bearing a main load, an amorphous phase of the high-toughness layers disperses stress through a shear band, a Sn / In gradient transition region (with the thickness of 300-600nm) at an interlayer interface relieves stress concentration, a strength-toughness inversion relationship is broken through, and the high-strength and high-toughness composite material is obtained. And high toughness (strength * elongation) is realized, and the performance is greatly improved compared with that of traditional secondary aluminum.

Description

Technical Field

[0001] The present invention relates to the technical field of recycled aluminum alloy materials, and in particular to a layered heterogeneous recycled aluminum alloy with a self-healing function and a preparation method thereof. Background Art

[0002] With the growing global demand for recycled aluminum resources, the secondary aluminum industry faces an urgent need to transition from low-end recycling to high-value utilization. Due to the complex sources of scrap aluminum raw materials and their highly variable composition, especially the difficulty in effectively controlling impurities such as iron and silicon, the mechanical properties and corrosion resistance of recycled aluminum often differ significantly from those of virgin aluminum alloys. While physical separation methods currently used in the industry can remove some impurities, their efficiency in separating micron-sized inclusions is limited. While flux refining processes can improve melt purity, they produce large amounts of toxic waste slag, posing serious environmental risks. Regarding material strengthening, traditional processes often rely on the addition of expensive alloying elements such as scandium and zirconium, which not only significantly increases production costs but also significantly reduces the strengthening effect due to the influence of impurities in the scrap aluminum. More importantly, the recent rise of self-healing aluminum alloy technology offers new solutions for addressing material damage. However, existing solutions often require temperatures exceeding 200°C to trigger healing or require the use of toxic elements such as bismuth, presenting significant limitations in practical application. These technical bottlenecks severely restrict the widespread application of recycled aluminum alloys in high-end fields such as aerospace and new energy vehicles, and also hinder the further improvement of aluminum resource recycling. Developing recycled aluminum alloys with excellent mechanical properties and self-repair capabilities without relying on expensive alloying elements or generating secondary pollution has become a key technical challenge that urgently needs to be overcome in the current materials field. Summary of the Invention

[0003] Technical problem to be solved: In response to the above technical problems, the purpose of the present invention is to provide a layered heterogeneous recycled aluminum alloy with self-healing function and a preparation method thereof, by adopting a structure in which high-strength layers (Al-Ni-Cu-Mg system) and high-toughness layers (Al-Fe-Si-Zn amorphous / nanocrystalline) are alternately stacked, the nano-scale Al3Ni precipitated phase of the high-strength layer is used to bear the main load, the amorphous phase of the high-toughness layer disperses the stress through the shear band, and the Sn / In gradient transition zone (thickness 300-600nm) at the interlayer interface relieves stress concentration, breaking through the strength-toughness inversion relationship, achieving a high strength-toughness product (strength × elongation), and greatly improving the performance compared with traditional recycled aluminum.

[0004] Technical solution: A layered heterogeneous recycled aluminum alloy with self-healing function, composed of alternating high-strength layers and high-toughness layers, wherein: The high-strength layer comprises an Al-Ni-Cu-Mg alloy having a nano-scale Al3Ni precipitation phase and a grain size of 1-3 μm; The high-toughness layer comprises an Al-Fe-Si-Zn amorphous / nanocrystalline composite structure, with the amorphous phase accounting for 40-50%; A concentration gradient transition zone of Sn / In elements is formed at the interlayer interface, and the thickness of the transition zone is 300-600nm. Furthermore, the preparation method of the high-strength layer is: Step 1: Mix 1.5-1.8wt.% Ni, 2.2-2.5wt.% Cu, 0.7-1.0wt.% Mg, 0.05-0.1wt.% Ti, 0.08-0.12wt.% Zr and the remaining recycled aluminum scraps, and place them under vacuum ≤10 -2 Pa induction furnace heated to 750-770 ℃ melt, add 0.1-0.3% of the total weight of the alloy Al-5Ti-1B grain refiner; Step 2: Use the single roller spinning method to control the copper roller linear speed to 25-30m / s and the cooling rate to 1×10 6 -5×10 6 K / s, to prepare thin ribbons with a thickness of 40-60 μm; Step 3: The thin strip is solution treated at 470-490℃ for 40-50min and then water quenched. It is then subjected to a double-stage aging treatment, first at 120-130℃ for 18-22h and then at 155-165℃ for 3-5h. Furthermore, the preparation method of the high-toughness layer is: Step 1: 1.0-1.5wt.% Zn, 0.3-0.5wt.% Sn, 0.15wt.% In, 0.03-0.08wt.% Sr and the remainder of recycled aluminum scrap are mixed, heated to 710-730°C in an argon protective atmosphere (oxygen content ≤ 50ppm) to melt, and an Al-10Sr modifier is added at 0.08-0.12% of the total weight of the alloy; Step 2: Use the spray casting technology to control the argon injection pressure to 0.3-0.6MPa and the cooling rate to 5×10 6 -2×10 7 K / s, preparing amorphous ribbons with a thickness of 15-25 μm; Step 3: Anneal the ribbon at 370-390° C. for 8-12 minutes to precipitate α-Al nanocrystals with a size of 20-50 nm in the amorphous matrix. Furthermore, the method for obtaining the recycled aluminum scrap is as follows: multi-stage eddy current sorting is used to remove particles ≥0.5 mm from the scrap aluminum; then, X-ray fluorescence online sorting is used to grade the Fe / Si content of the sorted aluminum material, and scrap aluminum material with an Fe content of 0.5-1.5wt% and a Si content of 0.3-1.2wt% is screened; and then recycled aluminum scrap with a particle size of 5-10 mm is obtained by deep-cold crushing with liquid nitrogen. The method for preparing the above-mentioned layered heterogeneous recycled aluminum alloy with self-healing function comprises the following steps: S1: Hot rolling treatment: hot rolling the high-toughness thin strip blank at 380-420°C with a deformation of 55-65%; S2: Layered stacking: hot-rolled high-strength layers and high-toughness layers are alternately stacked, with 8-12 layers stacked; S3: Diffusion bonding: cold rolling at 230-270℃ and 450-550MPa, with a total deformation of 75-85%; S4: Solution treatment: keep at 460-480℃ for 50-70min and then quench in water to make the concentration of Sn / In elements at the grain boundary reach 3-5 times the concentration in the matrix; S5: Aging treatment: first keep at 115-125℃ for 22-26h, then keep at 175-185℃ for 1.5-2.5h; S6: Thermomechanical training: preheat the material at 150-180°C for 10-30 min, apply 2-4 cyclic loads with a strain amplitude of 0.8-1.2% to form Sn / In nanonetwork channels with a width of 1-6 nm. Furthermore, the interlayer contact surface is sandblasted before cold rolling in S3, and the surface roughness Ra is controlled to be 0.5-1.0 μm. Furthermore, the frequency of the cyclic load in S6 is 0.01-0.1 Hz. Beneficial effects: 1. The present invention adopts a structure in which high-strength layers (Al-Ni-Cu-Mg system) and high-toughness layers (Al-Fe-Si-Zn amorphous / nanocrystalline) are alternately stacked. The nanoscale Al3Ni precipitated phase of the high-strength layer bears the main load, the amorphous phase of the high-toughness layer disperses stress through shear bands, and the Sn / In gradient transition zone (thickness 300-600nm) at the interlayer interface relieves stress concentration, breaking through the inverted strength-toughness relationship, achieving a high strength-toughness product (strength × elongation), and greatly improving the performance compared to traditional recycled aluminum. 2. The present invention adopts a three-stage pretreatment of "eddy current sorting + X-ray fluorescence grading + liquid nitrogen cryogenic crushing". Eddy current removes non-metallic inclusions, XRF accurately controls the content of Fe (0.5-1.5wt%) and Si (0.3-1.2wt%), and liquid nitrogen low-temperature (-150℃) crushing inhibits oxidation, reducing the impurity oxygen content of the recycled aluminum scrap, thereby reducing the porosity in subsequent smelting and narrowing the range of composition fluctuation. 3. The present invention adopts spray casting technology combined with controlled annealing, and ultra-fast cooling inhibits the precipitation of Fe / Si impurity phases. Annealing induces the precipitation of 20-50nm α-Al nanocrystals in the amorphous matrix, forming a composite mechanism of "amorphous phase hindering crack propagation + nanocrystal coordinated deformation", thereby improving the fracture toughness of the high-toughness layer. 4. The present invention adopts Sn / In microalloying (0.3-0.5wt% Sn, 0.15wt% In) combined with thermomechanical training. Cyclic load promotes the formation of a continuous nano-network of Sn / In elements at the grain boundaries. When heated at 150-180°C, a low-melting-point eutectic liquid phase is generated to autonomously fill the cracks, achieving a high crack width repair rate and extending the service life. 5. The present invention adopts sandblasting and low-temperature and high-pressure rolling to roughen the surface and increase the mechanical bite area, inhibit the coarsening of intermetallic compounds at the interface at low temperature, and promote the cross-layer diffusion of Al atoms under pressure, thereby increasing the interlayer bonding strength. The shear failure mode is transformed from interface peeling to matrix fracture. 6. The present invention adopts a step aging system to form a high-density GP zone in the low-temperature stage, and promotes the precipitation of Al3Ni phase from the GP zone in the high-temperature stage while maintaining coherence, narrowing the size distribution of the precipitated phase, improving the yield strength and maintaining the elongation. DETAILED DESCRIPTION The present invention provides a self-healing layered heterogeneous recycled aluminum alloy and a method for preparing the same. To clarify the objectives, technical solutions, and benefits of the present invention, the present invention will be further described below with reference to the following examples. It should be understood that the specific examples described herein are intended only to illustrate the present invention and are not intended to limit the present invention. Example 1 A method for preparing a layered heterogeneous recycled aluminum alloy with self-healing function comprises the following steps: S1. The method for obtaining recycled aluminum scrap comprises: using multi-stage eddy current separation to remove particles ≥0.5 mm from scrap aluminum; then using online X-ray fluorescence separation to classify the sorted aluminum by Fe / Si content, selecting scrap aluminum with an Fe content of 0.5-1.5 wt% and a Si content of 0.3-1.2 wt%; and then cryogenically crushing the scrap aluminum using liquid nitrogen to obtain recycled aluminum scrap with a particle size of 5-10 mm. S2. Preparation of high-strength layer: 1.5wt.% Ni, 2.2wt.% Cu, 0.7wt.% Mg, 0.05wt.% Ti, 0.08wt.% Zr and the remaining recycled aluminum scraps were mixed and heated in a vacuum of ≤10 -2 Pa induction furnace was heated to 760℃ and melted, and Al-5Ti-1B grain refiner accounting for 0.1% of the total weight of the alloy was added; the single roller spinning method was used to control the copper roller linear speed to 28m / s and the cooling rate to 1×10 6 K / s, and a 50 μm thick ribbon was prepared; the ribbon was solution treated at 480 °C for 45 min, water quenched, and then subjected to a two-stage aging treatment, first at 125 °C for 20 h and then at 160 °C for 4 h; S3. Preparation of the high-toughness layer: 1.0 wt.% Zn, 0.3 wt.% Sn, 0.15 wt.% In, 0.03 wt.% Sr and the remainder of recycled aluminum scrap were mixed and heated to 720°C in an argon atmosphere (oxygen content ≤ 50 ppm) to melt. 0.1% of the total weight of the alloy was added as an Al-10Sr modifier. Spray casting was performed with an argon injection pressure of 0.3-0.6 MPa and a cooling rate of 5 × 10 6 K / s, prepare an amorphous ribbon with a thickness of 20 μm; anneal the ribbon at 380 ° C for 10 min to obtain; S4 hot rolling treatment: the high-toughness layer thin strip blank is hot rolled at 400 ° C, with a deformation of 60%; S5. Layered stacking: Hot-rolled high-strength layers and high-toughness layers are alternately stacked, with a total of 10 layers. S6. Diffusion bonding: Cold rolled at 250°C and 500 MPa, with a total deformation of 80%. The interlayer contact surface was sandblasted before cold rolling to a surface roughness Ra of 0.5 μm. S7. Solution treatment: hold at 470°C for 60 min and then water quench; S8. Aging treatment: first at 120°C for 24 hours, then at 180°C for 2 hours; S9. Thermomechanical training: preheat the material at 170°C for 20 min, apply cyclic load with a strain amplitude of 1.0% three times, and the frequency of the cyclic load is 0.01-0.1 Hz. Example 2 A method for preparing a layered heterogeneous recycled aluminum alloy with self-healing function comprises the following steps: S1. The method for obtaining recycled aluminum scrap comprises: using multi-stage eddy current separation to remove particles ≥0.5 mm from scrap aluminum; then using online X-ray fluorescence separation to classify the sorted aluminum by Fe / Si content, selecting scrap aluminum with an Fe content of 0.5-1.5 wt% and a Si content of 0.3-1.2 wt%; and then cryogenically crushing the scrap aluminum using liquid nitrogen to obtain recycled aluminum scrap with a particle size of 5-10 mm. S2. Preparation of high-strength layer: 1.6wt.% Ni, 2.3wt.% Cu, 0.8wt.% Mg, 0.06wt.% Ti, 0.09wt.% Zr and the remaining recycled aluminum scraps were mixed and heated in a vacuum of ≤10 -2 Pa induction furnace was heated to 760℃ and melted, and Al-5Ti-1B grain refiner accounting for 0.2% of the total weight of the alloy was added; the single roller spinning method was used to control the copper roller linear speed at 28m / s and the cooling rate at 2×10 6K / s, and a 50 μm thick ribbon was prepared; the ribbon was solution treated at 480 °C for 45 min, water quenched, and then subjected to a two-stage aging treatment, first at 125 °C for 20 h and then at 160 °C for 4 h; S3. Preparation of the high-toughness layer: 1.1wt.% Zn, 0.4wt.% Sn, 0.15wt.% In, 0.04wt.% Sr and the remainder of recycled aluminum scrap were mixed and heated to 720°C in an argon atmosphere (oxygen content ≤ 50ppm) to melt. Al-10Sr modifier accounting for 0.1% of the total weight of the alloy was added. Spray casting technology was used, and the argon injection pressure was controlled at 0.3-0.6MPa and the cooling rate was 6×10 6 K / s, prepare an amorphous ribbon with a thickness of 20 μm; anneal the ribbon at 380 ° C for 10 min to obtain; S4 hot rolling treatment: the high-toughness layer thin strip blank is hot rolled at 400 ° C, with a deformation of 60%; S5. Layered stacking: Hot-rolled high-strength layers and high-toughness layers are alternately stacked, with a total of 10 layers. S6. Diffusion bonding: Cold rolled at 250°C and 500 MPa, with a total deformation of 80%. The interlayer contact surface was sandblasted before cold rolling to a surface roughness Ra of 0.6 μm. S7. Solution treatment: hold at 470°C for 60 min and then water quench; S8. Aging treatment: first at 120°C for 24 hours, then at 180°C for 2 hours; S9. Thermomechanical training: preheat the material at 170°C for 20 min, apply cyclic load with a strain amplitude of 1.0% three times, and the frequency of the cyclic load is 0.01-0.1 Hz. Example 3 A method for preparing a layered heterogeneous recycled aluminum alloy with self-healing function comprises the following steps: S1. The method for obtaining recycled aluminum scrap comprises: using multi-stage eddy current separation to remove particles ≥0.5 mm from scrap aluminum; then using online X-ray fluorescence separation to classify the sorted aluminum by Fe / Si content, selecting scrap aluminum with an Fe content of 0.5-1.5 wt% and a Si content of 0.3-1.2 wt%; and then cryogenically crushing the scrap aluminum using liquid nitrogen to obtain recycled aluminum scrap with a particle size of 5-10 mm. S2. Preparation of high-strength layer: 1.7wt.% Ni, 2.4wt.% Cu, 0.9wt.% Mg, 0.07wt.% Ti, 0.10wt.% Zr and the remaining recycled aluminum scraps were mixed and heated in a vacuum of ≤10 -2Pa induction furnace was heated to 760℃ and melted, and Al-5Ti-1B grain refiner accounting for 0.3% of the total weight of the alloy was added; the single roller spinning method was used to control the copper roller linear speed to 28m / s and the cooling rate to 3×10 6 K / s, and a 50 μm thick ribbon was prepared; the ribbon was solution treated at 480 °C for 45 min, water quenched, and then subjected to a two-stage aging treatment, first at 125 °C for 20 h and then at 160 °C for 4 h; S3. Preparation of the high-toughness layer: 1.2 wt.% Zn, 0.5 wt.% Sn, 0.15 wt.% In, 0.05 wt.% Sr and the remainder of recycled aluminum scrap were mixed and heated to 720°C in an argon atmosphere (oxygen content ≤ 50 ppm) to melt. Al-10Sr modifier accounting for 0.1% of the total weight of the alloy was added. Spray casting was performed with an argon injection pressure of 0.3-0.6 MPa and a cooling rate of 7×10 6 K / s, prepare an amorphous ribbon with a thickness of 20 μm; anneal the ribbon at 380 ° C for 10 min to obtain; S4 hot rolling treatment: the high-toughness layer thin strip blank is hot rolled at 400 ° C, with a deformation of 60%; S5. Layered stacking: Hot-rolled high-strength layers and high-toughness layers are alternately stacked, with a total of 10 layers. S6. Diffusion bonding: Cold rolled at 250°C and 500 MPa, with a total deformation of 80%. The interlayer contact surface was sandblasted before cold rolling to a surface roughness Ra of 0.8 μm. S7. Solution treatment: hold at 470°C for 60 min and then water quench; S8. Aging treatment: first at 120°C for 24 hours, then at 180°C for 2 hours; S9. Thermomechanical training: preheat the material at 170°C for 20 min, apply cyclic load with a strain amplitude of 1.0% three times, and the frequency of the cyclic load is 0.01-0.1 Hz. Example 4 A method for preparing a layered heterogeneous recycled aluminum alloy with self-healing function comprises the following steps: S1. The method for obtaining recycled aluminum scrap comprises: using multi-stage eddy current separation to remove particles ≥0.5 mm from scrap aluminum; then using online X-ray fluorescence separation to classify the sorted aluminum by Fe / Si content, selecting scrap aluminum with an Fe content of 0.5-1.5 wt% and a Si content of 0.3-1.2 wt%; and then cryogenically crushing the scrap aluminum using liquid nitrogen to obtain recycled aluminum scrap with a particle size of 5-10 mm. S2. Preparation of high-strength layer: 1.8wt.% Ni, 2.5wt.% Cu, 1.0wt.% Mg, 0.08wt.% Ti, 0.11wt.% Zr and the remaining recycled aluminum scraps were mixed and heated in a vacuum of ≤10 -2 Pa induction furnace was heated to 760℃ and melted, and Al-5Ti-1B grain refiner accounting for 0.2% of the total weight of the alloy was added; the single roller spinning method was used to control the copper roller linear speed to 28m / s and the cooling rate to 4×10 6 K / s, and a 50 μm thick ribbon was prepared; the ribbon was solution treated at 480 °C for 45 min, water quenched, and then subjected to a two-stage aging treatment, first at 125 °C for 20 h and then at 160 °C for 4 h; S3. Preparation of high-toughness layer: 1.3wt.% Zn, 0.4wt.% Sn, 0.15wt.% In, 0.06wt.% Sr and the remainder of recycled aluminum scrap were mixed and heated to 720°C in an argon atmosphere (oxygen content ≤ 50ppm) to melt. Al-10Sr modifier accounting for 0.1% of the total weight of the alloy was added. Spray casting technology was used, and the argon injection pressure was controlled at 0.3-0.6MPa and the cooling rate was 8×10 6 K / s, prepare an amorphous ribbon with a thickness of 20 μm; anneal the ribbon at 380 ° C for 10 min to obtain; S4 hot rolling treatment: the high-toughness layer thin strip blank is hot rolled at 400 ° C, with a deformation of 60%; S5. Layered stacking: Hot-rolled high-strength layers and high-toughness layers are alternately stacked, with a total of 10 layers. S6. Diffusion bonding: Cold rolled at 250°C and 500 MPa, with a total deformation of 80%. The interlayer contact surface was sandblasted before cold rolling to a surface roughness Ra of 1.0 μm. S7. Solution treatment: hold at 470°C for 60 min and then water quench; S8. Aging treatment: first at 120°C for 24 hours, then at 180°C for 2 hours; S9. Thermomechanical training: preheat the material at 170°C for 20 min, apply cyclic load with a strain amplitude of 1.0% three times, and the frequency of the cyclic load is 0.01-0.1 Hz. Example 5 A method for preparing a layered heterogeneous recycled aluminum alloy with self-healing function comprises the following steps: S1. The method for obtaining recycled aluminum scrap comprises: using multi-stage eddy current separation to remove particles ≥0.5 mm from scrap aluminum; then using online X-ray fluorescence separation to classify the sorted aluminum by Fe / Si content, selecting scrap aluminum with an Fe content of 0.5-1.5 wt% and a Si content of 0.3-1.2 wt%; and then cryogenically crushing the scrap aluminum using liquid nitrogen to obtain recycled aluminum scrap with a particle size of 5-10 mm. S2. Preparation of high-strength layer: 1.7wt.% Ni, 2.4wt.% Cu, 0.9wt.% Mg, 0.09wt.% Ti, 0.12wt.% Zr and the remaining recycled aluminum scraps were mixed and heated in a vacuum of ≤10 -2 Pa induction furnace was heated to 760℃ and melted, and Al-5Ti-1B grain refiner accounting for 0.2% of the total weight of the alloy was added; the single roller spinning method was used to control the copper roller linear speed to 28m / s and the cooling rate to 5×10 6 K / s, and a 50 μm thick ribbon was prepared; the ribbon was solution treated at 480 °C for 45 min, water quenched, and then subjected to a two-stage aging treatment, first at 125 °C for 20 h and then at 160 °C for 4 h; S3. Preparation of the high-toughness layer: 1.4 wt.% Zn, 0.4 wt.% Sn, 0.15 wt.% In, 0.07 wt.% Sr and the remainder of recycled aluminum scrap were mixed and heated to 720°C in an argon atmosphere (oxygen content ≤ 50 ppm) to melt. 0.1% of the total weight of the alloy was added as an Al-10Sr modifier. Spray casting was performed with an argon injection pressure of 0.3-0.6 MPa and a cooling rate of 9 × 10 6 K / s, prepare an amorphous ribbon with a thickness of 20 μm; anneal the ribbon at 380 ° C for 10 min to obtain; S4 hot rolling treatment: the high-toughness layer thin strip blank is hot rolled at 400 ° C, with a deformation of 60%; S5. Layered stacking: Hot-rolled high-strength layers and high-toughness layers are alternately stacked, with a total of 10 layers. S6. Diffusion bonding: Cold rolled at 250°C and 500 MPa, with a total deformation of 80%. The interlayer contact surface was sandblasted before cold rolling to a surface roughness Ra of 0.9 μm. S7. Solution treatment: hold at 470°C for 60 min and then water quench; S8. Aging treatment: first at 120°C for 24 hours, then at 180°C for 2 hours; S9. Thermomechanical training: preheat the material at 170°C for 20 min, apply cyclic load with a strain amplitude of 1.0% three times, and the frequency of the cyclic load is 0.01-0.1 Hz. Example 6 A method for preparing a layered heterogeneous recycled aluminum alloy with self-healing function comprises the following steps: S1. The method for obtaining recycled aluminum scrap comprises: using multi-stage eddy current separation to remove particles ≥0.5 mm from scrap aluminum; then using online X-ray fluorescence separation to classify the sorted aluminum by Fe / Si content, selecting scrap aluminum with an Fe content of 0.5-1.5 wt% and a Si content of 0.3-1.2 wt%; and then cryogenically crushing the scrap aluminum using liquid nitrogen to obtain recycled aluminum scrap with a particle size of 5-10 mm. S2. Preparation of high-strength layer: 1.7wt.% Ni, 2.4wt.% Cu, 0.9wt.% Mg, 0.1wt.% Ti, 0.10wt.% Zr and the remaining recycled aluminum scraps were mixed and heated in a vacuum of ≤10 -2 Pa induction furnace was heated to 760℃ and melted, and Al-5Ti-1B grain refiner accounting for 0.2% of the total weight of the alloy was added; the single roller spinning method was used to control the copper roller linear speed to 28m / s and the cooling rate to 4×10 6 K / s, and a 50 μm thick ribbon was prepared; the ribbon was solution treated at 480 °C for 45 min, water quenched, and then subjected to a two-stage aging treatment, first at 125 °C for 20 h and then at 160 °C for 4 h; Preparation of the high-toughness layer: 1.5 wt.% Zn, 0.4 wt.% Sn, 0.15 wt.% In, 0.08 wt.% Sr and the remainder of recycled aluminum scrap were mixed and heated to 720°C in an argon atmosphere (oxygen content ≤ 50 ppm) to melt. 0.1% of the total weight of the alloy was added as an Al-10Sr modifier. Spray casting was performed with an argon injection pressure of 0.3-0.6 MPa and a cooling rate of 1×10 7 K / s, prepare an amorphous ribbon with a thickness of 20 μm; anneal the ribbon at 380 ° C for 10 min to obtain; S4 hot rolling treatment: the high-toughness layer thin strip blank is hot rolled at 400 ° C, with a deformation of 60%; S5. Layered stacking: Hot-rolled high-strength layers and high-toughness layers are alternately stacked, with a total of 10 layers. S6. Diffusion bonding: Cold rolled at 250°C and 500 MPa, with a total deformation of 80%. The interlayer contact surface was sandblasted before cold rolling to a surface roughness Ra of 0.8 μm. S7. Solution treatment: hold at 470°C for 60 min and then water quench; S8. Aging treatment: first at 120°C for 24 hours, then at 180°C for 2 hours; S9. Thermomechanical training: preheat the material at 170°C for 20 min, apply cyclic load with a strain amplitude of 1.0% three times, and the frequency of the cyclic load is 0.01-0.1 Hz. Example 7 A method for preparing a layered heterogeneous recycled aluminum alloy with self-healing function comprises the following steps: S1. The method for obtaining recycled aluminum scrap comprises: using multi-stage eddy current separation to remove particles ≥0.5 mm from scrap aluminum; then using online X-ray fluorescence separation to classify the sorted aluminum by Fe / Si content, selecting scrap aluminum with an Fe content of 0.5-1.5 wt% and a Si content of 0.3-1.2 wt%; and then cryogenically crushing the scrap aluminum using liquid nitrogen to obtain recycled aluminum scrap with a particle size of 5-10 mm. S2. Preparation of high-strength layer: 1.7wt.% Ni, 2.4wt.% Cu, 0.9wt.% Mg, 0.09wt.% Ti, 0.10wt.% Zr and the remaining recycled aluminum scraps were mixed and heated in a vacuum of ≤10 -2 Pa induction furnace was heated to 760℃ and melted, and Al-5Ti-1B grain refiner accounting for 0.2% of the total weight of the alloy was added; the single roller spinning method was used to control the copper roller linear speed to 28m / s and the cooling rate to 4×10 6 K / s, and a 50 μm thick ribbon was prepared; the ribbon was solution treated at 480 °C for 45 min, water quenched, and then subjected to a two-stage aging treatment, first at 125 °C for 20 h and then at 160 °C for 4 h; Preparation of the high-toughness layer: 1.4 wt.% Zn, 0.4 wt.% Sn, 0.15 wt.% In, 0.06 wt.% Sr and the remainder of recycled aluminum scrap were mixed and heated to 720°C in an argon atmosphere (oxygen content ≤ 50 ppm) to melt. 0.1% of the total weight of the alloy was added as an Al-10Sr modifier. Spray casting was performed with an argon injection pressure of 0.3-0.6 MPa and a cooling rate of 2×10 7 K / s, prepare an amorphous ribbon with a thickness of 20 μm; anneal the ribbon at 380 ° C for 10 min to obtain; S4 hot rolling treatment: the high-toughness layer thin strip blank is hot rolled at 400 ° C, with a deformation of 60%; S5. Layered stacking: Hot-rolled high-strength layers and high-toughness layers are alternately stacked, with a total of 10 layers. S6. Diffusion bonding: Cold rolled at 250°C and 500 MPa, with a total deformation of 80%. The interlayer contact surface was sandblasted before cold rolling to a surface roughness Ra of 0.7 μm. S7. Solution treatment: hold at 470°C for 60 min and then water quench; S8. Aging treatment: first at 120°C for 24 hours, then at 180°C for 2 hours; S9. Thermomechanical training: preheat the material at 170°C for 20 min, apply cyclic load with a strain amplitude of 1.0% three times, and the frequency of the cyclic load is 0.01-0.1 Hz. Example 8 A method for preparing a layered heterogeneous recycled aluminum alloy with self-healing function comprises the following steps: S1. The method for obtaining recycled aluminum scrap comprises: using multi-stage eddy current separation to remove particles ≥0.5 mm from scrap aluminum; then using online X-ray fluorescence separation to classify the sorted aluminum by Fe / Si content, selecting scrap aluminum with an Fe content of 0.5-1.5 wt% and a Si content of 0.3-1.2 wt%; and then cryogenically crushing the scrap aluminum using liquid nitrogen to obtain recycled aluminum scrap with a particle size of 5-10 mm. S2. Preparation of high-strength layer: 1.7wt.% Ni, 2.4wt.% Cu, 0.9wt.% Mg, 0.09wt.% Ti, 0.10wt.% Zr and the remaining recycled aluminum scraps were mixed and heated in a vacuum of ≤10 -2 Pa induction furnace was heated to 760℃ and melted, and Al-5Ti-1B grain refiner accounting for 0.2% of the total weight of the alloy was added; the single roller spinning method was used to control the copper roller linear speed to 28m / s and the cooling rate to 4×10 6 K / s, and a 50 μm thick ribbon was prepared; the ribbon was solution treated at 480 °C for 45 min, water quenched, and then subjected to a two-stage aging treatment, first at 125 °C for 20 h and then at 160 °C for 4 h; S3. Preparation of the high-toughness layer: 1.4 wt.% Zn, 0.4 wt.% Sn, 0.15 wt.% In, 0.06 wt.% Sr and the remainder of recycled aluminum scrap were mixed and heated to 720°C in an argon atmosphere (oxygen content ≤ 50 ppm) to melt. 0.1% of the total weight of the alloy was added as an Al-10Sr modifier. Spray casting was performed with an argon injection pressure of 0.3-0.6 MPa and a cooling rate of 1×10 7 K / s, prepare an amorphous ribbon with a thickness of 20 μm; anneal the ribbon at 380 ° C for 10 min to obtain; S4 hot rolling treatment: the high-toughness layer thin strip blank is hot rolled at 400 ° C, with a deformation of 60%; S5. Layered stacking: Hot-rolled high-strength layers and high-toughness layers are alternately stacked, with a total of 10 layers. S6. Diffusion bonding: Cold rolled at 250°C and 500 MPa, with a total deformation of 80%. The interlayer contact surface was sandblasted before cold rolling to a surface roughness Ra of 0.6 μm. S7. Solution treatment: hold at 470°C for 60 min and then water quench; S8. Aging treatment: first at 120°C for 24 hours, then at 180°C for 2 hours; S9. Thermomechanical training: preheat the material at 170°C for 20 min, apply cyclic load with a strain amplitude of 1.0% three times, and the frequency of the cyclic load is 0.01-0.1 Hz. Example 9 A method for preparing a layered heterogeneous recycled aluminum alloy with self-healing function comprises the following steps: S1. The method for obtaining recycled aluminum scrap comprises: using multi-stage eddy current separation to remove particles ≥0.5 mm from scrap aluminum; then using online X-ray fluorescence separation to classify the sorted aluminum by Fe / Si content, selecting scrap aluminum with an Fe content of 0.5-1.5 wt% and a Si content of 0.3-1.2 wt%; and then cryogenically crushing the scrap aluminum using liquid nitrogen to obtain recycled aluminum scrap with a particle size of 5-10 mm. S2. Preparation of high-strength layer: 1.7wt.% Ni, 2.4wt.% Cu, 0.9wt.% Mg, 0.09wt.% Ti, 0.10wt.% Zr and the remaining recycled aluminum scraps were mixed and heated in a vacuum of ≤10 -2 Pa induction furnace was heated to 760℃ and melted, and Al-5Ti-1B grain refiner accounting for 0.2% of the total weight of the alloy was added; the single roller spinning method was used to control the copper roller linear speed to 28m / s and the cooling rate to 4×10 6 K / s, and a 50 μm thick ribbon was prepared; the ribbon was solution treated at 480 °C for 45 min, water quenched, and then subjected to a two-stage aging treatment, first at 125 °C for 20 h and then at 160 °C for 4 h; S3. Preparation of the high-toughness layer: 1.4 wt.% Zn, 0.4 wt.% Sn, 0.15 wt.% In, 0.06 wt.% Sr and the remainder of recycled aluminum scrap were mixed and heated to 720°C in an argon atmosphere (oxygen content ≤ 50 ppm) to melt. Al-10Sr modifier accounting for 0.1% of the total weight of the alloy was added. Spray casting technology was used, and the argon injection pressure was controlled at 0.3-0.6 MPa and the cooling rate was 9×10 6 K / s, prepare an amorphous ribbon with a thickness of 20 μm; anneal the ribbon at 380 ° C for 10 min to obtain; S4 hot rolling treatment: the high-toughness layer thin strip blank is hot rolled at 400 ° C, with a deformation of 60%; S5. Layered stacking: Hot-rolled high-strength layers and high-toughness layers are alternately stacked, with a total of 10 layers. S6. Diffusion bonding: Cold rolled at 250°C and 500 MPa, with a total deformation of 80%. The interlayer contact surface was sandblasted before cold rolling to a surface roughness Ra of 0.5 μm. S7. Solution treatment: hold at 470°C for 60 min and then water quench; S8. Aging treatment: first at 120°C for 24 hours, then at 180°C for 2 hours; S9. Thermomechanical training: preheat the material at 170°C for 20 min, apply cyclic load with a strain amplitude of 1.0% three times, and the frequency of the cyclic load is 0.01-0.1 Hz. Comparative Example 1 The difference between this embodiment and embodiment 8 is that the high-strength layers and the high-toughness layers are not stacked alternately, and five layers of high-strength layers are stacked on top of five layers of high-toughness layers. Comparative Example 2 The difference between this embodiment and embodiment 8 is that the cooling rate of the high-toughness layer is 1×10 5 K / s. Comparative Example 3 The difference between this embodiment and embodiment 8 is that the S9 thermomechanical training is omitted. Comparative Example 4 The difference between this embodiment and embodiment 8 is that the interlayer contact surface in S6 is not sandblasted, and the surface roughness Ra is 0.2 μm. Performance test: The tensile strength was determined according to ASTM E8 / E8M: gauge length 50 mm, strain rate 1×10-3 / s, and the average value of three specimens was taken. The elongation was determined according to ASTM E8 / E8M: the gauge length was measured after fracture and the average value of three specimens was taken. Determination of self-healing efficiency: prefabricated 100 μm crack → heated at 150 °C for 1 h → SEM measurement of crack closure width ratio (healed width / original width × 100%); The interfacial bonding strength was determined according to ASTM D3165: lap shear test, loading rate 1 mm / min, minimum of 5 specimens; The results are shown in Table 1 below: Table 1

Claims

1. A layered heterogeneous recycled aluminum alloy with self-healing function, characterized in that: It is composed of alternating layers of high strength and high toughness, of which: The high-strength layer comprises an Al-Ni-Cu-Mg alloy having a nano-scale Al3Ni precipitation phase and a grain size of 1-3 μm; The high-toughness layer comprises an Al-Fe-Si-Zn amorphous / nanocrystalline composite structure, with the amorphous phase accounting for 40-50%; A concentration gradient transition zone of Sn / In elements is formed at the interlayer interface, and the thickness of the transition zone is 300-600nm.

2. The layered heterogeneous recycled aluminum alloy with self-healing function according to claim 1, characterized in that: The preparation method of the high-strength layer is: Step 1: Mix 1.5-1.8wt.% Ni, 2.2-2.5wt.% Cu, 0.7-1.0wt.% Mg, 0.05-0.1wt.% Ti, 0.08-0.12wt.% Zr and the remaining recycled aluminum scraps, and place them under vacuum ≤10 -2 Pa induction furnace heated to 750-770 ℃ melt, add 0.1-0.3% of the total weight of the alloy Al-5Ti-1B grain refiner; Step 2: Use the single roller spinning method to control the copper roller linear speed to 25-30m / s and the cooling rate to 1×10 6 -5×10 6 K / s, to prepare thin ribbons with a thickness of 40-60 μm; Step 3: The thin strip is solution treated at 470-490℃ for 40-50min and then water quenched. It is then subjected to a double-stage aging treatment, first at 120-130℃ for 18-22h and then at 155-165℃ for 3-5h.

3. The layered heterogeneous recycled aluminum alloy with self-healing function according to claim 1, characterized in that: The preparation method of the high-toughness layer is: Step 1: Mix 1.0-1.5wt.% Zn, 0.3-0.5wt.% Sn, 0.15wt.% In, 0.03-0.08wt.% Sr and the remainder of recycled aluminum scrap, heat to 710-730°C under an argon protective atmosphere to melt, and add 0.08-0.12% of Al-10Sr modifier to the total weight of the alloy; Step 2: Use the spray casting technology to control the argon injection pressure to 0.3-0.6MPa and the cooling rate to 5×10 6 -2×10 7 K / s, preparing amorphous ribbons with a thickness of 15-25 μm; Step 3: Anneal the ribbon at 370-390°C for 8-12 minutes.

4. The layered heterogeneous recycled aluminum alloy with self-healing function according to claim 2 or 3, characterized in that: The method for obtaining the recycled aluminum scrap comprises: using multi-stage eddy current sorting to remove particles ≥0.5 mm from waste aluminum; then using X-ray fluorescence online sorting to grade the Fe / Si content of the sorted aluminum materials, screening waste aluminum materials with an Fe content of 0.5-1.5wt% and a Si content of 0.3-1.2wt%; and then obtaining recycled aluminum scraps with a particle size of 5-10 mm through liquid nitrogen cryogenic crushing.

5. The method for preparing a layered heterogeneous recycled aluminum alloy with self-healing function according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1: Hot rolling treatment: hot rolling the high-toughness layer thin strip blank at 380-420°C with a deformation of 55-65% to partially crystallize the amorphous phase into nanocrystalline with a grain size controlled at 25-55nm; S2: Layered stacking: hot-rolled high-strength layers and high-toughness layers are alternately stacked, with 8-12 layers stacked; S3: Diffusion bonding: Cold rolling at 230-270℃ and 450-550MPa, with a total deformation of 75-85%; S4: Solution treatment: keep at 460-480℃ for 50-70min and then quench in water; S5: Aging treatment: first keep at 115-125℃ for 22-26h, then keep at 175-185℃ for 1.5-2.5h; S6: Thermomechanical training: preheat the material at 150-180°C for 10-30 min, apply 2-4 cycles of cyclic load with a strain amplitude of 0.8-1.2%, and obtain the result.

6. The method for preparing a layered heterogeneous recycled aluminum alloy with self-healing function according to claim 5, characterized in that: In the above-mentioned S3, the interlayer contact surface is sandblasted before cold rolling, and the surface roughness Ra is controlled to be 0.5-1.0 μm.

7. The method for preparing a layered heterogeneous recycled aluminum alloy with self-healing function according to claim 5, characterized in that: The frequency of the cyclic load in S6 is 0.01-0.1 Hz.

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