Nanoparticle toughened scrap aluminum alloy and method of making
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JILIN UNIVERSITY
- Filing Date
- 2026-07-10
- Publication Date
- 2026-08-07
AI Technical Summary
现有研究通过在合金制备过程中添加0.2wt.%及以上稀土等元素将富铁相变质为颗粒状或骨骼状含铁金属间化合物，以改善废料铝合金的强度，但添加0.2wt.%及以上稀土元素将增加成本
现有技术通常通过降低Fe含量、提高原铝添加比例或采用加入稀土元素来改善废料铝合金的力学性能。该路线不仅会增加原料和工艺成本，还会降低废料铝的实际利用率，并且难以彻底避免Fe元素在再生铝中的累积。与其不同，本发明以高Fe含量为0.85-0.99wt.%的废料Al-Mg-Si合金为基体，不以添加稀土元素为主要手段，而是通过引入微量NbC、NbB2和Al3Nb纳米颗粒实现强韧化，所述纳米颗粒在废料铝合金中的总质量占比为0.05-0.15 wt.%，从而在提高废料铝利用率的同时降低了对稀土元素和复杂除铁工艺的依赖。同时，本发明通过纳米颗粒与元素之间的相互作用、配比、工艺和工艺参数的协同调控作用，有利于改善纳米颗粒在铝熔体中的分散均匀性，降低纳米颗粒直接加入时易团聚、分布不均的问题。本发明能够在保持再生铝工业化工艺兼容性的基础上，实现废料铝合金的组织优化和强韧化。在组织方面，NbC、NbB2和Al3Nb纳米颗粒均匀分散于铝基体中，可同时发挥晶粒细化、细化富铁相尺寸和抑制元素偏析作用。在宏观性能方面，本发明实现合金在室温下强塑性的同步提高:纳米颗粒强韧化废料铝合金的屈服强度≥325.4 MPa，抗拉强度≥366.9 MPa，延伸率≥15.7%。对比现有的废料铝合金强度和塑性，本发明获得的废料铝合金抗拉强度和延伸率分别提高了17.8%和18.0%。上述结果表明，本发明能够在较高Fe含量废料铝合金中，通过微量纳米颗粒调控富铁相和基体组织的细化，实现强度和塑性的同步提升，具有Fe容忍度高、废料铝利用率高、纳米颗粒添加量低、工艺适应性强和综合力学性能优良等优势。
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Abstract
Description
Technical Field
[0001] This invention relates to the field of recycling and reusing scrap aluminum alloys containing high Fe impurities, specifically to a nanoparticle-strengthened scrap aluminum alloy and its preparation method. Background Technology
[0002] With the deepening of the goals of carbon peaking and carbon neutrality, the circular economy and efficient resource utilization have become important development directions. Aluminum alloys, due to their excellent recyclability, demonstrate significant advantages in green and sustainable development. Large quantities of scrap aluminum generated by manufacturing industries such as automobiles and aerospace, due to their controllable sources, have become high-value-added secondary aluminum resources, and are expected to become an important supplement to my country's supply of metallic aluminum and aluminum alloys. However, it is difficult to effectively remove Fe elements during the recycling process of aluminum alloys. Fe elements easily accumulate in recycled aluminum alloys and form coarse iron-rich phases, significantly reducing the material's plasticity and limiting its engineering applications. Therefore, improving the mechanical properties of aluminum alloys containing iron impurities has become a core issue that urgently needs to be addressed to expand their applications. Existing research improves the strength of scrap aluminum alloys by adding 0.2 wt.% or more of rare earth elements during alloy preparation to transform the iron-rich phase into granular or skeletal iron-containing intermetallic compounds, but adding 0.2 wt.% or more of rare earth elements increases costs. Furthermore, existing technologies improve performance by enhancing the morphology of iron-rich phases through high-cooling-rate casting, ultrasonic cavitation and acoustic flow effects, and complex large-deformation processes. However, this leads to complex operating procedures, hindering industrial production, and makes it difficult to simultaneously improve strength and toughness. Therefore, how to simultaneously improve the strength and toughness of alloys while reducing the amount of rare earth elements added and simplifying the process, and achieve stable industrial production of alloys, is a pressing technical challenge that needs to be addressed. Summary of the Invention
[0003] To address the aforementioned technical challenges, this invention provides a nanoparticle-strengthened and toughened scrap aluminum alloy, the preparation method of which includes the following steps: (1) At room temperature, niobium-titanium-aluminum alloy powder, BN powder and carbon powder are mixed in a mass ratio of 60-80:15-18:6-8 and mixed uniformly at a speed of 30-70 r / min for 15-25 hours to prepare mixed powder 1; The niobium-titanium-aluminum alloy powder has a particle size of 25-65 micrometers; the BN powder has a particle size of 50-250 micrometers; and the carbon powder has a particle size of 15-300 micrometers. (2) The mixed powder 1 obtained in step (1) is coated with pure aluminum strip and then hot-drawn at 300-400℃ to obtain wire A; The mass ratio of the pure aluminum strip to the mixed powder 1 obtained in step (1) is 1.3-2.9:6.8-9.6; The hot drawing process is carried out at 310-380℃, with 3-8 deformation cycles, each with a deformation amount of 15%-20%. (3) Heat the wire A obtained in step (2) to 935-985℃ to form a liquid flow, and at the same time introduce high temperature and stable pure aluminum liquid. After applying ultrasonic treatment with a power of 1.9-2.6kW and a frequency of 20-25kHz, cast it to obtain intermediate alloy wire B containing nanoparticles. The mass ratio of the wire A to the pure aluminum liquid is 2-6:6-10; In the aforementioned nanoparticle-containing master alloy wire B, the nanoparticle mass percentage is 5 wt.%-18 wt.%. (4) After holding the scrap aluminum alloy at 780-880℃ for 20-50 minutes, a melt is obtained. Then, the intermediate alloy wire B containing nanoparticles obtained in step (3) is added. The mass ratio of intermediate alloy wire B to the melt is 0.8%-2.0%:1. After mechanical stirring for 2-5 minutes, the scrap aluminum alloy melt reinforced by intermediate alloy wire B is obtained. The scrap aluminum alloy is a 6-series aluminum alloy; by mass percentage, the composition of the scrap aluminum alloy mainly includes: Mg: 0.65-1.0 wt.%; Si: 0.4-0.65 wt.%; Fe: 0.85-0.99 wt.%; Mn: 0.40-0.75 wt.%; Cu: 0.20-0.45 wt.%; Zn: 0.02-0.17 wt.%; Ti: 0.02-0.11 wt.%; the remainder is Al; (5) The intermediate alloy wire B reinforced scrap aluminum alloy melt obtained in step (4) is poured, homogenized at 520-580℃ for 6-14 hours, and air-cooled to obtain a homogenized ingot. (6) The homogenized ingot obtained in step (5) is extruded and T6 treated to obtain nanoparticle-strengthened scrap aluminum alloy; the extrusion is carried out at 400-480℃, the extrusion rate is 0.3-4.5m / min, and the extrusion ratio is 22-29:1; the T6 treatment is carried out at 510-540℃ for 0.5-2.5h, followed by water quenching, and then artificial aging treatment at 160-175℃ for 4-8h. The aforementioned nanoparticle-strengthened waste aluminum alloy contains 0.05 wt.%-0.15 wt.% nanoparticles; The size of the iron-rich phase in the nanoparticle-strengthened scrap aluminum alloy is 1.75-5.62µm. The size of the iron-rich phase within this range indicates that the iron-rich phase is effectively refined, and its adverse effects on the material's plasticity and fracture behavior are relatively small. The nanoparticle-strengthened scrap aluminum alloy contains uniformly dispersed NbC, NbB2, and Al3Nb nanoparticles with particle sizes of 60-120nm, 75-230nm, and 260-400nm, respectively. The nanoparticle-strengthened scrap aluminum alloy has a yield strength ≥325.4 MPa, a tensile strength ≥366.9 MPa, and an elongation ≥15.7% at room temperature.
[0004] Further, the niobium-titanium-aluminum alloy powder in step (1) has a particle size of 30-60 micrometers; the BN powder has a particle size of 80-180 micrometers; and the carbon powder has a particle size of 30-200 micrometers.
[0005] Further, in step (2), the pure aluminum strip is coated with the obtained mixed powder 1 at a mass ratio of 1.5-2.6:7.8-9.2; The hot drawing process is carried out at 330-350℃, with 3-5 deformation cycles, each with a deformation amount of 15%-20%.
[0006] Further, in step (3), the wire A is heated to 955-965°C to form a liquid flow, and at the same time, high-temperature stable pure aluminum liquid is introduced. After ultrasonic treatment with a power of 2.0-2.2kW and a frequency of 20-23kHz, it is cast into shape to obtain intermediate alloy wire B containing nanoparticles. The mass ratio of the wire A to the pure aluminum liquid is 3-4.8:7-9.5; In the aforementioned nanoparticle-containing intermediate alloy wire B, the mass percentage of nanoparticles is 6 wt.%-12 wt.%.
[0007] Further, the scrap aluminum alloy described in step (4) is kept at 800-850℃ for 30-45 minutes, and intermediate alloy wire B containing nanoparticles obtained in step (3) is added. The mass ratio of intermediate alloy wire B to the melt is 0.8%-1.5%:1. After mechanical stirring for 3-4 minutes, the intermediate alloy wire B reinforced scrap aluminum alloy melt is obtained.
[0008] Further, the composition of the scrap aluminum alloy mentioned in step (4) mainly includes: Mg: 0.75-0.9wt.%; Si: 0.50-0.65wt.%; Fe: 0.88-0.97wt.%; Mn: 0.56-0.72wt.%; Cu: 0.21-0.35wt.%; Zn: 0.09-0.14wt.%; Ti: 0.02-0.06wt.%; the remainder is Al; Furthermore, the homogenization process described in step (5) involves homogenizing at 540-580℃ for 6-8 hours and then air-cooling to obtain a homogenized ingot.
[0009] Further, the extrusion described in step (6) is carried out at 420-450°C, with an extrusion rate of 0.6-3.5 m / min and an extrusion ratio of 24-27:1.
[0010] Further, the T6 treatment in step (6) involves solution treatment at 525-540℃ for 0.5-1.5h, followed by water quenching, and then artificial aging treatment at 170-175℃ for 5-8h; the nanoparticle-strengthened waste aluminum alloy contains 0.08 wt.%-0.14 wt.% nanoparticles.
[0011] Furthermore, the nanoparticle-strengthened scrap aluminum alloy has a yield strength of 325.4-345.1 MPa, a tensile strength of 366.9-375.4 MPa, and an elongation of 15.7-18.0% at room temperature.
[0012] Compared with the prior art, the advantages of the present invention are: Existing technologies typically improve the mechanical properties of scrap aluminum alloys by reducing Fe content, increasing the proportion of primary aluminum added, or adding rare earth elements. This approach not only increases raw material and process costs but also reduces the actual utilization rate of scrap aluminum and makes it difficult to completely avoid the accumulation of Fe in recycled aluminum. In contrast, this invention uses scrap Al-Mg-Si alloys with a high Fe content of 0.85-0.99 wt.% as the matrix. Instead of relying primarily on adding rare earth elements, it achieves toughening by introducing trace amounts of NbC, NbB2, and Al3Nb nanoparticles. These nanoparticles account for 0.05-0.15 wt.% of the total mass of the scrap aluminum alloy, thereby improving the utilization rate of scrap aluminum while reducing dependence on rare earth elements and complex iron removal processes. Furthermore, this invention, through the interaction, proportioning, process, and synergistic control of nanoparticles and elements, improves the dispersion uniformity of nanoparticles in the aluminum melt, reducing the problems of agglomeration and uneven distribution that occur when nanoparticles are directly added. This invention optimizes the microstructure and enhances the toughness of scrap aluminum alloys while maintaining compatibility with industrial-scale recycled aluminum processes. Microstructurally, NbC, NbB2, and Al3Nb nanoparticles are uniformly dispersed in the aluminum matrix, simultaneously refining grain size, reducing the size of the iron-rich phase, and suppressing elemental segregation. In terms of macroscopic properties, this invention achieves a simultaneous improvement in the alloy's strength and ductility at room temperature: the yield strength of the nanoparticle-strengthened scrap aluminum alloy is ≥325.4 MPa, tensile strength is ≥366.9 MPa, and elongation is ≥15.7%. Compared to existing scrap aluminum alloys, the scrap aluminum alloy obtained by this invention shows an increase in tensile strength and elongation of 17.8% and 18.0%, respectively. These results demonstrate that this invention can simultaneously improve strength and ductility in high-Fe-content scrap aluminum alloys by controlling the iron-rich phase and refining the matrix microstructure through trace amounts of nanoparticles. It offers advantages such as high Fe tolerance, high scrap aluminum utilization, low nanoparticle addition, strong process adaptability, and excellent comprehensive mechanical properties. Attached Figure Description
[0013] Figure 1 The image shows the room temperature tensile stress-strain curve of the nanoparticle-strengthened waste aluminum alloy 1 in Example 2.
[0014] Figure 2 The figure shows the room temperature tensile stress-strain curve of the nanoparticle-strengthened waste aluminum alloy 2 in Example 3.
[0015] Figure 3 This is a microscopic image of the nanoparticle-strengthened waste aluminum alloy 1 in Example 2 under an optical microscope.
[0016] Figure 4 This is a microscopic image of the aluminum alloy 2, which was toughened by nanoparticles in Example 3, under an optical microscope.
[0017] Figure 5 The image shows the microstructure of the scrap aluminum alloy in Comparative Example 1 under an optical microscope. Detailed Implementation Example 1
[0018] The preparation method of the intermediate alloy wire includes the following steps: Step 1: Mix niobium-titanium-aluminum alloy powder, BN powder and carbon powder in a mass ratio of 60-80:15-18:6-8, and mix them uniformly at a speed of 65 r / min for 20 hours to prepare mixed powder 1. The niobium-titanium-aluminum alloy powder has a particle size of 35-60 micrometers; the BN powder has a particle size of 90-150 micrometers; and the carbon powder has a particle size of 50-130 micrometers. Step 2: Coat the mixed powder 1 obtained in Step 1 with pure aluminum strip, and then perform hot drawing at 300-400℃ to obtain wire A; The mass ratio of the pure aluminum strip to the mixed powder 1 obtained in step 1 is 2.4:8.2; The hot drawing process is carried out at 340℃, with a single-pass deformation of 15%-20% for 3-5 passes. Step 3: Heat the wire A obtained in Step 2 to 960-965℃ to form a liquid flow, and at the same time introduce high-temperature stable pure aluminum liquid. After applying ultrasonic treatment with a power of 2.1kW and a frequency of 22kHz, cast it to obtain intermediate alloy wire B containing nanoparticles. The mass ratio of the wire A to the pure aluminum liquid is 4:9; In the aforementioned nanoparticle-containing intermediate alloy wire B, the nanoparticles account for 9 wt.% of the total mass, and the particle sizes of NbC, NbB2, and Al3Nb nanoparticles are 80-111 nm, 95-200 nm, and 280-350 nm, respectively. Example 2
[0019] The preparation method of nanoparticle-strengthened and toughened scrap aluminum alloy 1 includes the following steps: Step 1: After holding the scrap aluminum alloy at 810-830℃ for 30-40 minutes to obtain a melt, add the intermediate alloy wire B containing nanoparticles obtained in Example 1. The mass ratio of intermediate alloy wire B to the melt is 1.5%:1. After mechanical stirring for 3 minutes, the scrap aluminum alloy melt reinforced by intermediate alloy wire B is obtained. The scrap aluminum alloy is a 6-series aluminum alloy; by mass percentage, the composition of the scrap aluminum alloy mainly includes: Mg: 0.85wt.%; Si: 0.65wt.%; Fe: 0.95wt.%; Mn: 0.65wt.%; Cu: 0.32wt.%; Zn: 0.13wt.%; Ti: 0.03wt.%; the remainder is Al; Step 2: The intermediate alloy wire B reinforced scrap aluminum alloy melt obtained in Step 1 is poured, homogenized at 540-550℃ for 6 hours, and then air-cooled to obtain a homogenized ingot. Step 3: The homogenized ingot obtained in Step 2 is extruded and then treated with T6 to obtain nanoparticle-strengthened and toughened scrap aluminum alloy; the extrusion is carried out at 430℃, the extrusion rate is 0.8m / min, and the extrusion ratio is 26:1; the T6 treatment is carried out by solution treatment at 530℃ for 1-1.5h, water quenching, and then artificial aging treatment at 170℃ for 6h. The aforementioned nanoparticle-strengthened aluminum alloy waste contains 0.14 wt.% nanoparticles; The room temperature tensile stress-strain curve of the nanoparticle-strengthened waste aluminum alloy 1 described in this embodiment is as follows: Figure 1 As shown, its yield strength, tensile strength, and elongation at room temperature are 334.5 MPa, 371.2 MPa, and 16.4%, respectively. The microstructure of the nanoparticle-strengthened waste aluminum alloy 1 described in this embodiment under a light microscope is as follows: Figure 3 As shown, the elements remain uniformly distributed without significant segregation. The size of the iron-rich phase in the nanoparticle-reinforced aluminum alloy 1 is 2.45-4.86 µm. Therefore, it can be concluded that the nanoparticle-reinforced aluminum alloy 1, even under conditions of high Fe residue, can maintain high strength and high ductility to meet application requirements. Example 3
[0020] The preparation method of nanoparticle-strengthened and toughened scrap aluminum alloy 2 includes the following steps: Step 1: After holding the scrap aluminum alloy at 810-830℃ for 30-40 minutes to obtain a melt, add the intermediate alloy wire B containing nanoparticles obtained in Example 1. The mass ratio of intermediate alloy wire B to the melt is 1.1%:1. After mechanical stirring for 3 minutes, the scrap aluminum alloy melt reinforced by intermediate alloy wire B is obtained. The scrap aluminum alloy is a 6-series aluminum alloy; by mass percentage, the composition of the scrap aluminum alloy mainly includes: Mg: 0.85wt.%; Si: 0.65wt.%; Fe: 0.95wt.%; Mn: 0.65wt.%; Cu: 0.32wt.%; Zn: 0.13wt.%; Ti: 0.03wt.%; the remainder is Al; Step 2: The intermediate alloy wire B reinforced scrap aluminum alloy melt obtained in Step 1 is poured, homogenized at 540-550℃ for 6 hours, and then air-cooled to obtain a homogenized ingot. Step 3: The homogenized ingot obtained in Step 2 is extruded and then treated with T6 to obtain nanoparticle-strengthened and toughened scrap aluminum alloy; the extrusion process is carried out at 430℃, extrusion rate of 0.8m / min, and extrusion ratio of 26:1; the T6 treatment is carried out by solution treatment at 530℃ for 1-1.5h, water quenching, and then artificial aging treatment at 170℃ for 6h. The aforementioned nanoparticle-strengthened aluminum alloy waste contains 0.10 wt.% nanoparticles; The nanoparticle-strengthened aluminum alloy 2 described in this embodiment has the following yield strength, tensile strength, and elongation at room temperature: Figure 2 As shown, the values are 325.4 MPa, 366.9 MPa, and 15.7%, respectively. The microstructure of the nanoparticle-strengthened waste aluminum alloy 2 described in this embodiment under a light microscope is as follows: Figure 4 As shown, there are no significant local enrichment regions among the elements, and they maintain an ideal uniform distribution. The size of the iron-rich phase in the nanoparticle-strengthened waste aluminum alloy 2 is 3.42-5.36µm.
[0021] Comparative Example 1 In his master's thesis, "Microstructure Control and Property Study of 6061 Recycled Aluminum Alloy," Huang Zhengyang investigated the room temperature tensile properties of scrap aluminum alloys. The scrap aluminum alloy provided was obtained after multiple deformation passes (more than 10 deformations) followed by T6 treatment (solution treatment at 540℃ for 4 hours, followed by artificial aging treatment at 180℃ for 12 hours). Its tensile strength and elongation at room temperature were 314.9 MPa and 13.9%, respectively. The chemical composition of the scrap aluminum alloy is as follows: Mg: 1.2 wt.%; Si: 0.67 wt.%; Fe: 1.0 wt.%; Mn: 0.8 wt.%; Cu: 0.72 wt.%; Ti: 0.15 wt.%; Zn: 0.18 wt.%; Cr: 0.07 wt.%; Sn: 0.06 wt.%; Pb: 0.05 wt.%; RE (rare earth elements): 0.2 wt.%; Sr: 0.05 wt.%; the remainder is Al. The nanoparticle-strengthened aluminum alloys prepared in Examples 2 and 3 have nanoparticle contents of 0.14 wt.% and 0.10 wt.%, respectively. They are similar to the aluminum alloys in Comparative Example 1 and have similar Fe contents. Moreover, the amounts of metals added in the nanoparticle-strengthened aluminum alloys of Examples 1, such as Mg (0.85 wt.%), Mn (0.65 wt.%), Cu (0.32 wt.%), and Zn (0.13 wt.%), are all less than the amounts added in Comparative Example 1 (Mg: 1.2 wt.%, Mn: 0.8 wt.%, Cu: 0.72 wt.%, Zn: 0.18 wt.%). In addition, 0.2 wt.% RE was added to the comparative example, which further increased the corresponding production cost. Furthermore, the scrap aluminum alloy provided in Comparative Example 1 was obtained through multiple deformation passes, making the process relatively complex. The nanoparticle-strengthened scrap aluminum alloys obtained in Examples 2 and 3 of this invention only require a single extrusion, without multiple deformation passes. Compared to Comparative Example 1 (solution at 540℃ for 4 hours + artificial aging at 180℃ for 12 hours), the process conditions in Examples 2 and 3 of this invention are significantly optimized: only 530℃ solution treatment <1.5 hours and 170℃ aging ≤6 hours are required, greatly simplifying the process. Comparing the microstructure, the microstructure and iron-rich phase in the scrap aluminum alloy of Comparative Example 1 showed no significant improvement, while the segregation phenomenon in the nanoparticle-strengthened scrap aluminum alloys of Examples 2 and 3 of this invention was significantly improved, and the iron-rich phase was refined. The nanoparticle-reinforced and toughened scrap aluminum alloy 1 obtained in Example 2 of this invention exhibits 17.8% and 18.0% higher tensile strength and elongation at room temperature compared to the scrap aluminum alloy in Comparative Example 1 at the same temperature, respectively. This demonstrates that the nanoparticle-reinforced and toughened scrap aluminum alloy obtained by this invention, with a simplified process and lower processing cost, exhibits significantly better strength and ductility at room temperature than the high-processing-cost scrap aluminum alloy in Comparative Example 1. Furthermore, the nanoparticle-reinforced and toughened scrap aluminum alloy 2 obtained in Example 3 of this invention, despite having a lower nanoparticle content, still surpasses the scrap aluminum alloy in Comparative Example 1 in both strength and ductility. Specifically, the tensile strength and elongation of this invention are increased by 16.5% and 12.9% compared to Comparative Example 1, respectively. Therefore, the nanoparticle-reinforced and toughened scrap aluminum alloys obtained in these examples of this invention possess higher strength and ductility with lower raw material costs and a simplified process than existing technologies, exhibiting superior strength and ductility compared to Comparative Example 1.
[0022] The room temperature mechanical properties of the scrap aluminum alloy in Comparative Example 1 and the nanoparticle-strengthened scrap aluminum alloys in Examples 2 and 3 are summarized in the table below: Table 1 Comparison of room temperature mechanical properties of scrap aluminum alloys in comparative examples and various embodiments
[0023] In existing technologies, to obtain good overall performance, alloys typically require the addition of 0.2 wt% or more of rare earth elements. However, the total nanoparticle content defined in claim 1 of this invention is less than 0.15 wt%, without introducing any precious metal elements. Furthermore, Examples 2 and 3 of this invention only require solution treatment at 530°C for less than 1.5 hours followed by artificial aging at 170°C for no more than 6 hours. In contrast, Comparative Example 1 requires solution treatment at 540°C for 4 hours, followed by artificial aging at 180°C for 12 hours. This invention significantly simplifies the process, shortens the time, and reduces the corresponding temperatures, thereby significantly reducing raw material costs and strategic resource dependence. Moreover, with lower costs and a simpler processing technology, the microstructure of Examples 2 and 3 of this invention shows a significant improvement in segregation compared to Comparative Example 1, refining the iron-rich phase and exhibiting superior overall performance compared to Comparative Example 1 (scrap aluminum alloy), successfully achieving simultaneous optimization of tensile strength and elongation. In particular, compared with Comparative Example 1, the nanoparticle-strengthened aluminum alloy 1 obtained in Example 2 achieved a tensile strength of 371.2 MPa and an elongation of 16.4% at room temperature. Compared with the existing aluminum alloys for scrap, the tensile strength and elongation of Example 2 were increased by 17.8% and 18.0%, respectively. In summary, compared with the prior art, the present invention reduces the addition of rare earth elements, simplifies the process, and breaks through the technical bottleneck of simultaneously improving strength and toughness, achieving simultaneous improvement of strength and toughness. In addition, the process parameters of each embodiment of the present invention are different, resulting in different performance. This shows that the superior effect of the present invention is not determined by a certain component or process, but is achieved through the synergistic regulation of component interaction, proportion, process, and process parameters. Only within the scope of the claims can the best technical effect be achieved.
Claims
1. A nanoparticle-strengthened and toughened scrap aluminum alloy, characterized in that, Its preparation method includes the following steps: (1) At room temperature, niobium-titanium-aluminum alloy powder, BN powder and carbon powder are mixed in a mass ratio of 60-80:15-18:6-8 and mixed uniformly at a speed of 30-70 r / min for 15-25 hours to prepare mixed powder 1; The niobium-titanium-aluminum alloy powder has a particle size of 25-65 micrometers; the BN powder has a particle size of 50-250 micrometers; and the carbon powder has a particle size of 15-300 micrometers. (2) The mixed powder 1 obtained in step (1) is coated with pure aluminum strip and then hot-drawn at 300-400℃ to obtain wire A; The mass ratio of the pure aluminum strip to the mixed powder 1 obtained in step (1) is 1.3-2.9:6.8-9.6; The hot drawing process is carried out at 310℃-380℃, with 3-8 deformation cycles, each deformation being 15%-20%. (3) Heat the wire A obtained in step (2) to 935-985℃ to form a liquid flow, and at the same time introduce high temperature and stable pure aluminum liquid. After applying ultrasonic treatment with a power of 1.9-2.6kW and a frequency of 20-25kHz, cast it to obtain intermediate alloy wire B containing nanoparticles. The mass ratio of the wire A to the pure aluminum liquid is 2-6:6-10; In the aforementioned nanoparticle-containing master alloy wire B, the nanoparticle mass percentage is 5 wt.%-18 wt.%. (4) After holding the scrap aluminum alloy at 780-880℃ for 20-50 minutes, a melt is obtained. Then, the intermediate alloy wire B containing nanoparticles obtained in step (3) is added. The mass ratio of intermediate alloy wire B to the melt is 0.8%-2.0%:
1. After mechanical stirring for 2-5 minutes, the scrap aluminum alloy melt reinforced by intermediate alloy wire B is obtained. The scrap aluminum alloy is a 6-series aluminum alloy; by mass percentage, the composition of the scrap aluminum alloy mainly includes: Mg: 0.65-1.0 wt.%; Si: 0.4-0.65 wt.%; Fe: 0.85-0.99 wt.%; Mn: 0.40-0.75 wt.%; Cu: 0.20-0.45 wt.%; Zn: 0.02-0.17 wt.%; Ti: 0.02-0.11 wt.%; the remainder is Al; (5) The intermediate alloy wire B reinforced scrap aluminum alloy melt obtained in step (4) is poured, homogenized at 520-580℃ for 6-14 hours, and air-cooled to obtain a homogenized ingot. (6) The homogenized ingot obtained in step (5) is extruded and T6 treated to obtain nanoparticle-strengthened scrap aluminum alloy; the extrusion is carried out at 400-480℃, the extrusion rate is 0.3-4.5m / min, and the extrusion ratio is 22-29:1; the T6 treatment is carried out at 510-540℃ for 0.5-2.5h, followed by water quenching, and then artificial aging treatment at 160-175℃ for 4-8h. The aforementioned nanoparticle-strengthened scrap aluminum alloy contains 0.05 wt.%-0.15 wt.% nanoparticles; The size of the iron-rich phase in the nanoparticle-strengthened scrap aluminum alloy is 1.75-5.62µm. The size of the iron-rich phase within this range indicates that the iron-rich phase is effectively refined, and its adverse effects on the material's plasticity and fracture behavior are relatively small. The nanoparticle-strengthened scrap aluminum alloy contains uniformly dispersed NbC, NbB2, and Al3Nb nanoparticles with particle sizes of 60-120nm, 75-230nm, and 260-400nm, respectively. The nanoparticle-strengthened scrap aluminum alloy has a yield strength ≥325.4 MPa, a tensile strength ≥366.9 MPa, and an elongation ≥15.7% at room temperature.
2. The nanoparticle-strengthened and toughened waste aluminum alloy according to claim 1, characterized in that, The niobium-titanium-aluminum alloy powder in step (1) has a particle size of 30-60 micrometers; the BN powder has a particle size of 80-180 micrometers; and the carbon powder has a particle size of 30-200 micrometers.
3. The nanoparticle-strengthened and toughened scrap aluminum alloy according to claim 1, characterized in that, In step (2), the pure aluminum strip is coated with the obtained mixed powder 1 at a mass ratio of 1.5-2.6:7.8-9.
2. The hot drawing process is carried out at 330-350℃, with 3-5 deformation cycles, each with a deformation amount of 15%-20%.
4. The nanoparticle-strengthened and toughened waste aluminum alloy according to claim 1, characterized in that, In step (3), the wire A is heated to 955-965℃ to form a liquid flow, and at the same time, high-temperature stable pure aluminum liquid is introduced. After ultrasonic treatment with a power of 2.0-2.2kW and a frequency of 20-23kHz, it is cast into shape to obtain intermediate alloy wire B containing nanoparticles. The mass ratio of the wire A to the pure aluminum liquid is 3-4.8:7-9.5; In the aforementioned nanoparticle-containing intermediate alloy wire B, the mass percentage of nanoparticles is 6 wt.%-12 wt.%.
5. The nanoparticle-strengthened and toughened waste aluminum alloy according to claim 1, characterized in that, The scrap aluminum alloy described in step (4) is kept at 800-850℃ for 30-45 minutes, and the intermediate alloy wire B containing nanoparticles obtained in step (3) is added. The mass ratio of intermediate alloy wire B to the melt is 0.8%-1.5%:
1. After mechanical stirring for 3-4 minutes, the scrap aluminum alloy melt reinforced by intermediate alloy wire B is obtained.
6. The nanoparticle-strengthened and toughened waste aluminum alloy according to claim 1, characterized in that, The composition of the scrap aluminum alloy mentioned in step (4) mainly includes: Mg: 0.75-0.9wt.%; Si: 0.50-0.65wt.%; Fe: 0.88-0.97wt.%; Mn: 0.56-0.72wt.%; Cu: 0.21-0.35wt.%; Zn: 0.09-0.14wt.%; Ti: 0.02-0.06wt.%; the remainder is Al.
7. The nanoparticle-strengthened and toughened waste aluminum alloy according to claim 1, characterized in that, The homogenization process described in step (5) involves homogenizing at 540-580℃ for 6-8 hours and then air-cooling to obtain a homogenized ingot.
8. The nanoparticle-strengthened and toughened waste aluminum alloy according to claim 1, characterized in that, The extrusion described in step (6) is carried out at 420-450℃, with an extrusion rate of 0.6-3.5m / min and an extrusion ratio of 24-27:
1.
9. The nanoparticle-strengthened and toughened waste aluminum alloy according to claim 1, characterized in that, The T6 treatment described in step (6) involves solution treatment at 525-540℃ for 0.5-1.5h, followed by water quenching, and then artificial aging treatment at 170-175℃ for 5-8h; the nanoparticle-strengthened waste aluminum alloy contains 0.08 wt.%-0.14 wt.% nanoparticles.
10. The nanoparticle-strengthened and toughened scrap aluminum alloy according to claim 1, characterized in that, The nanoparticle-strengthened aluminum alloy has a yield strength of 325.4-345.1 MPa, a tensile strength of 366.9-375.4 MPa, and an elongation of 15.7-18.0% at room temperature.