Uniform heat treatment process for 6000 series aluminum alloy based on icosahedral quasicrystal dispersion phase
The homogenization heat treatment process controlled by icosahedral quasicrystalline structure solves the problem of dispersed phase coarsening in traditional methods, realizes the formation of high-density quasicrystalline structure, improves the strength and ductility of 6000 series aluminum alloys, and meets the requirements of automotive lightweighting.
Patent Information
- Application Number
- CN202610311861.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-03-16
- Publication Date
- 2026-05-29
AI Technical Summary
Traditional homogenization methods for 6000 series aluminum alloys result in large dispersed phase size and low number density, leading to reduced dispersion strengthening effect and making it difficult to meet the requirements of automotive lightweighting for high strength and ductility.
A homogenization heat treatment process based on the icosahedral quasicrystalline structure is adopted. By controlling the heating rate and holding time, the transformation of the icosahedral quasicrystalline structure to the cubic structure is suppressed, forming a high-density quasicrystalline dispersed phase with a size of 10-20 nm, which is highly coherent with the matrix.
It significantly improves the strength and elongation of the alloy, achieves excellent dispersion strengthening effect, and enhances the strength and toughness of the alloy.
Smart Images
Figure CN122105275A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a heat treatment process for homogenizing 6000 series aluminum alloys based on icosahedral quasicrystalline dispersed phase regulation. Specifically, it relates to a heat treatment method for 6000 series (Al-Mg-Si-Cu-Mn) aluminum alloys. This falls under the field of aluminum alloy heat treatment technology. Background Technology
[0002] With the increasing severity of global warming, reducing fuel consumption and greenhouse gas emissions has become a major issue facing countries and the entire automotive industry. Lightweighting of automobiles is one of the important ways to achieve energy conservation and emission reduction. 6000 series aluminum alloys, due to their medium-to-high strength, good formability, excellent corrosion resistance, and weldability, have become the preferred material for automotive lightweighting. The demand for high-strength and ductile aluminum alloys is increasing in automotive lightweighting. In Al-Mg-Si-Cu alloys, the addition of Mn can promote the precipitation of dispersed phases, inhibit recrystallization, and reduce stress concentration. Currently, traditional homogenization treatment methods for 6000 series aluminum alloys mostly use 500~600℃. Under this heat treatment, the dispersed phases are large in size and have low number density, leading to a reduction in dispersion strengthening effect. Therefore, it is urgent to optimize the homogenization heat treatment process to stimulate dispersion strengthening ability, thereby improving the strength and toughness of the alloy. Summary of the Invention
[0003] The technical problem to be solved by this invention is to propose a heat treatment process for homogenizing 6000 series aluminum alloys based on icosahedral quasicrystalline dispersed phases, thereby improving the strength and toughness of the alloy.
[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: To effectively improve the content and strengthening ability of the dispersed phase in Al(Fe,Mn,Cr)Si, this invention develops a novel homogenization heat treatment process that can effectively suppress the transformation of the icosahedral quasicrystalline I-Al(Fe,Mn,Cr)Si dispersed phase to the cubic α-Al(Fe,Mn,Cr)Si dispersed phase, thereby obtaining a novel alloy with the icosahedral quasicrystalline dispersed phase as the main dispersed phase, thus effectively improving the strength and elongation of the alloy.
[0005] A heat treatment process for homogenizing 6000 series aluminum alloys based on icosahedral quasi-crystalline dispersed phases includes the following steps: The process includes casting, homogenization treatment, pre-hot rolling heat treatment, hot rolling, cold rolling, solution treatment, and aging of aluminum alloy ingots. The casting method uses 99.98% industrial pure aluminum, pure Mg, Al-Si master alloy, Al-Cu master alloy, Al-Mn master alloy, and Al-Cr master alloy as raw materials. The alloys are cast using semi-continuous casting at a temperature of 690℃~750℃ and a cooling rate of 50~90mm / min. The ingot diameter is 178mm and the length is 2 meters. The homogenization heat treatment involves heating the aluminum alloy ingot to 350℃~450℃ at a heating rate of 20℃ / h~100℃ / h, holding for 1h-6h, then cooling to 250℃~300℃ at a rate of 20℃ / h~40℃ / h, holding for 2-6h, then heating to 350~400℃ at a rate of 20℃ / h~50℃ / h, holding for 1-4h, followed by forced cooling via air or water cooling.
[0006] In the Al-Mg-Si-Cu aluminum alloy, Mg accounts for 0.8-3.2 wt.%, Si accounts for 0.2-1.2 wt.%, Cu accounts for 0.4-1.8 wt.%, Mn accounts for 0.5-1.5 wt.%, and the balance is Al and unavoidable impurities.
[0007] The homogenized icosahedral quasicrystalline structure has a dispersed phase size of 10-20 nm and is highly coherent with the matrix.
[0008] The preheating treatment before hot rolling involves holding the homogenized ingot at 490℃~540℃ for 1h-4h.
[0009] The hot rolling process is as follows: the ingots that have undergone preheating treatment are directly taken out of the furnace for hot rolling, and are hot rolled to 4-8mm in 5-15 passes. Each pass of hot rolling is then held in the furnace for at least 5 minutes.
[0010] The cold rolling process involves cold rolling a hot-rolled plate to 1-3 mm.
[0011] The solution treatment process involves holding the solution at a temperature of 520℃ to 570℃ for 10 minutes to 6 hours, followed by water quenching to room temperature.
[0012] The aging process is as follows: aging temperature 170-185℃, holding time 1-10h.
[0013] The aluminum alloy obtained by the present invention is based on the homogenization heat treatment process of 6000 series aluminum alloy controlled by icosahedral quasicrystalline dispersed phase.
[0014] The aluminum alloy obtained by this invention has a yield strength of 489.3–500 MPa, a tensile strength of 531.0–542.1 MPa, and an elongation of 11.3–12.3%.
[0015] The aluminum alloy obtained by this invention has an icosahedral quasicrystalline structure with a dispersed phase size of 10-20 nm after homogenization, which is highly coherent with the matrix.
[0016] The application of the aluminum alloy obtained by this invention in automobiles.
[0017] An automotive component is prepared from the aluminum alloy of the present invention.
[0018] The present invention has the following beneficial effects: Traditional homogenization temperatures for 6000 series aluminum alloys are typically between 500 and 560°C. However, at this temperature, the α-Al(FeMn)Si dispersed phase rapidly coarsens, reaching a size of 100–300 nm, while its number density decreases, leading to a sharp decline in its dispersion strengthening ability. This invention relates to a homogenization heat treatment process for 6000 series aluminum alloys based on the icosahedral quasicrystalline structure dispersed phase. This homogenization heat treatment is a low-temperature heat treatment, with a heating rate of 20°C / h to 100°C / h to 350°C to 450°C, held for 1–6 hours, followed by cooling at 20°C / h to 40°C / h to 250°C to 300°C, held for 2–6 hours, then heated at 20°C / h to 50°C / h to 350–400°C, held for 1–4 hours, and finally forced cooling by air or water. The main purpose of this heat treatment process is to suppress the transformation of the icosahedral quasicrystalline I-Al(Fe,Mn,Cr)Si dispersed phase to the cubic α-Al(Fe,Mn,Cr)Si dispersed phase, thereby obtaining a microstructure dominated by the quasicrystalline I phase and stimulating the dispersion strengthening ability of the Al-Mg-Si alloy, thus further improving the strength and toughness of the alloy.
[0019] The heat treatment process is characterized by the presence of a high-density quasicrystalline structure I dispersed phase in the alloy, with a size of 10~20nm, which is highly coherent with the matrix and has excellent dispersion strengthening potential. Attached Figure Description
[0020] Figure 1 The images shown are bright-field TEM images, HAADF-STEM images, and high-magnification atomic structure diagrams of the dispersed phase after homogenization of alloys in Example 1 and Comparative Example 1; wherein, Figures a, b, and c represent Example 1; and Figures d, e, and f represent Comparative Example 1. Figure 2 Figure a shows the BSE diagrams of the second phase after solution treatment of the alloys in Example 1 and Comparative Example 1, where Figure a represents Example 1 and Figure b represents Comparative Example 1. Figure 3 Figure 1 shows bright-field TEM images of the dispersed phase under peak aging conditions of alloys in Example 1 and Comparative Example 1, where Figure a represents Example 1 and Figure b represents Comparative Example 1. Detailed Implementation
[0021] The present invention will be further described in detail below with reference to specific embodiments. The following embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Example 1
[0022] The experimental alloy has the composition Al-1.1Mg-0.9Si-0.5Cu-0.5Mn. The alloy was prepared by casting using 99.9% industrial pure Al, 99.9% pure Mg, 99.9% pure Mn, Al-10%Si master alloy, and Al-49.5%Cu master alloy as raw materials. It then underwent homogenization heat treatment, heating to 400℃ at a rate of 50℃ / h and holding for 2 hours, then cooling to 250℃ at a rate of 20℃ / h and holding for 2 hours, followed by heating to 400℃ at a rate of 30℃ / h and holding for 1 hour, and finally water cooling to room temperature. The resulting alloy had dimensions of 20×30×70 mm. 3 The homogenized sample was held at 510℃ for 2 hours, then hot-rolled from 20 mm to 6 mm in 6 passes, and then cold-rolled into a 1 mm thick sheet. The rolled sheet was then solution-treated at 560℃ for 30 minutes, then water-quenched to room temperature, and immediately subjected to artificial aging treatment at 180℃ for 6 hours.
[0023] Hardness testing was performed with a load of 500g and a holding time of 10s. At least 10 points were taken from the entire surface of each sample to ensure data accuracy, with an error not exceeding ±3%. Tensile testing at room temperature was conducted on an MTS C43.504 testing machine at a tensile rate of 1mm / min. Three parallel specimens were used for each sample. After fracture, the yield strength σ was calculated according to the national standard GB / T228-2002. s Tensile strength σ b The elongation δ was also measured. The microstructure of the alloy was observed using a transmission electron microscope (TEM), while atomic resolution HAADF-STEM was performed using a spherical aberration-corrected electron microscope with an accelerating voltage of 300 kV. The transmission sample was prepared using an electrolytic double-jet system. The double-jet solution consisted of 70% methanol + 30% nitric acid, at a temperature of -25°C to -30°C, a voltage of 15–20 V, and a current of 50–70 mA.
[0024] Comparative Example 1
[0025] This comparative example is basically the same as Example 1, except that the homogenization heat treatment process design is different, while the subsequent deformation, processing and heat treatment processes are basically the same.
[0026] In this comparative example, the homogenization heat treatment process was carried out by heating to 560℃ at a rate of 50℃ / h and holding at that temperature for 6h.
[0027] Experimental results (1) Diffuse phase Figure 1 The images show bright-field TEM images, HAADF-STEM images, and high-magnification atomic structure diagrams of the dispersed phases after homogenization of the alloys of Example 1 and Comparative Example 1. From the FFT images and high-magnification atomic structure diagrams, it can be seen that the dispersed phase formed in Example 1 has clear icosahedral quasicrystalline diffraction pattern characteristics. After further high-temperature homogenization, the quasicrystalline I dispersed phase in Example 1 transforms into the cubic α dispersed phase in Comparative Example 1. Table 2 shows that the dispersed phase in the alloy of Example 1 has a small size and a high number density, while the dispersed phase in Comparative Example 1 has a coarser size. This indicates that using the icosahedral quasicrystalline structure as the main dispersed phase can promote the precipitation of fine dispersed phases.
[0028] Table 1 Alloy homogenization heat treatment process scheme
[0029] Table 2. Results of dispersed phase analysis after homogenization
[0030] Methods for calculating size and number density: direct measurement; number density is expressed in statistical units (μm). -3 The number of diffuse phases within.
[0031] (2) Primary phase and diffuse phase after deformation Deformation microstructure after different homogenization heat treatments, such as Figure 2 and Figure 3 As shown in Table 3, the analysis results are as follows. In both Example 1 and Comparative Example 1 alloys, the primary phases were effectively dissolved after rolling and solution treatment, and the second phase in Example 1 alloy was smaller in size. Compared to the dispersed phase formed after homogenization, the dispersed phase under peak aging conditions underwent significant growth, and the dispersed phase in Example 1 alloy was smaller and had a higher number density than that in Comparative Example 1 alloy.
[0032] Table 3. Analysis results of the deformation microstructure of the alloy after different homogenization heat treatments.
[0033] (3) Tensile properties Table 4. Yield strength, tensile strength, and elongation of alloys with different homogenization treatments
[0034] As shown in Table 4, compared with the traditional homogenization process of Comparative Example 1, the alloy treated by the method of the present invention significantly improves the yield strength and tensile strength of the alloy at a similar elongation level. Moreover, the method of the present invention takes less time than the traditional process, thus having a certain economic advantage.
[0035] Therefore, it can be seen that during the homogenization heat treatment of 400℃ / 2h, 250℃ / 2h, and 400℃ / 1h in this invention, the nucleation rate of the quasicrystalline I dispersed phase is the highest, resulting in a small size and the highest number density. The subsequent heating at 250℃ / 2h and 400℃ / 1h can suppress the structural transformation of the quasicrystalline I dispersed phase to the cubic α dispersed phase, thus giving the quasicrystalline I phase high thermal stability.
[0036] In this invention, the test standard for yield strength, tensile strength and elongation is GB / T228.1-2021 Standard for Tensile Testing of Metallic Materials.
[0037] Example 2
[0038] The experimental alloy has the composition Al-0.8Mg-0.2Si-0.4Cu-1.5Mn. The alloy was prepared by casting using 99.9% industrial pure Al, 99.9% pure Mg, 99.9% pure Mn, Al-10%Si master alloy, and Al-49.5%Cu master alloy as raw materials. It then underwent homogenization heat treatment, heating to 350℃ at a rate of 20℃ / h and holding for 1 h, followed by cooling to 300℃ at 40℃ / h and holding for 6 h, then heating to 350℃ at 20℃ / h and holding for 4 h, and finally water cooling to room temperature. Finally, a sample with dimensions of 20×30×70 mm was formed. 3 The homogenized sample was held at 490℃ for 1 hour, then hot-rolled from 20 mm to 8 mm in 5 passes, and then cold-rolled into a 3 mm thick sheet. The rolled sheet was then solution-treated at 520℃ for 10 minutes, then water-quenched to room temperature, and immediately artificially aged at 170℃ for 1 hour.
[0039] The alloy obtained in this embodiment has a yield strength of 498.2 MPa, a tensile strength of 536.5 MPa, and an elongation of 11.3%.
[0040] Example 3
[0041] The experimental alloy has the composition Al-3.2Mg-1.2Si-1.8Cu-1.0Mn. The alloy was prepared by casting using 99.9% industrial pure Al, 99.9% pure Mg, 99.9% pure Mn, Al-10%Si master alloy, and Al-49.5%Cu master alloy as raw materials. It then underwent homogenization heat treatment, heating to 450℃ at a rate of 100℃ / h and holding for 6 hours, followed by cooling to 280℃ at 30℃ / h and holding for 3 hours, then heating to 380℃ at 50℃ / h and holding for 4 hours, and finally water cooling to room temperature. The resulting alloy had dimensions of 20×30×70 mm. 3The homogenized sample was held at 540℃ for 4 hours, then hot-rolled from 20 mm to 4 mm in 15 passes, and then cold-rolled into a 1 mm thick sheet. The rolled sheet was then solution-treated at 570℃ for 6 hours, then water-quenched to room temperature, and immediately artificially aged at 185℃ for 10 hours.
[0042] The alloy obtained in this embodiment has a yield strength of 489.3 MPa, a tensile strength of 531.0 MPa, and an elongation of 11.6%.
[0043] Example 4
[0044] The experimental alloy has the composition Al-2.0Mg-1.0Si-1.0Cu-1.0Mn. The alloy was prepared by casting using 99.9% industrial pure Al, 99.9% pure Mg, 99.9% pure Mn, Al-10%Si master alloy, and Al-49.5%Cu master alloy as raw materials. It then underwent homogenization heat treatment, heating to 350℃ at a rate of 60℃ / h and holding for 1 hour, followed by cooling to 250℃ at 30℃ / h and holding for 2 hours, then heating to 350℃ at 40℃ / h and holding for 1 hour, and finally water cooling to room temperature. The resulting alloy had dimensions of 20×30×70 mm. 3 The homogenized sample was held at 500℃ for 1 hour, then hot-rolled from 20 mm to 4 mm in 15 passes, and then cold-rolled into a 2 mm thick sheet. The rolled sheet was then solution-treated at 550℃ for 1 hour, then water-quenched to room temperature, and immediately artificially aged at 175℃ for 1 hour.
[0045] The alloy obtained in this embodiment has a yield strength of 497.2 MPa, a tensile strength of 535.2 MPa, and an elongation of 12.3%.
[0046] It should be understood that, in order to simplify this disclosure and aid in understanding one or more of the various aspects of the invention, features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof in the above description of exemplary embodiments of the invention. However, this method of disclosure should not be interpreted as reflecting an intention that the claimed invention requires more features than expressly recited in each claim. Rather, as reflected in the claims, inventive aspects lie in fewer than all the features of the foregoingly disclosed embodiments. Therefore, the claims, following the detailed description, are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of the invention.
[0047] Although the invention has been described with reference to a limited number of embodiments, those skilled in the art will understand from the foregoing description that other embodiments are conceivable within the scope of the invention described herein. Furthermore, it should be noted that the language used in this specification has been chosen primarily for readability and instructional purposes, and not for the purpose of interpreting or limiting the subject matter of the invention. Therefore, many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the appended claims. The disclosure of the invention is illustrative and not restrictive, and the scope of the invention is defined by the appended claims.
[0048] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A heat treatment process for homogenizing 6000 series aluminum alloys based on icosahedral quasi-crystalline dispersed phase regulation, characterized in that, Includes the following steps: S01, casting of aluminum alloy ingots; S02, Homogenization heat treatment: The aluminum alloy ingot is heated to 350℃~450℃ at a heating rate of 20℃ / h~100℃ / h and held for 1h-6h. Then it is cooled to 250℃~300℃ at a heating rate of 20℃ / h~40℃ / h and held for 2-6h. Then it is heated to 350~400℃ at a heating rate of 20℃ / h~50℃ / h and held for 1-4h. Finally, it is forced to cool by air or water. S03, preheating treatment before hot rolling: hold the homogenized ingot at 490℃~540℃ for 1h-4h. S04, Hot rolling: The ingots that have undergone preheating treatment are directly taken out of the furnace for hot rolling, and are hot rolled to 4-8mm in 5-15 passes. Each hot rolling pass is held in the furnace for at least 5 minutes to obtain hot-rolled plates. S05, Cold rolling: Cold rolling hot-rolled sheet to 1-3mm to obtain cold-rolled sheet; S06, solution treatment: cold-rolled sheet is kept at 520℃~570℃ for 10min~6h, then water quenched to room temperature; S07, Aging: Aging temperature 170~185℃, holding time 1h~10h.
2. The heat treatment process for homogenizing 6000 series aluminum alloys based on icosahedral quasi-crystalline dispersed phase regulation according to claim 1, characterized in that, In S01, the casting method is to use 99.98% industrial pure aluminum, pure Mg, Al-Si master alloy, Al-Cu master alloy, Al-Mn master alloy and Al-Cr master alloy as raw materials. The alloy is completed by semi-continuous casting, with a casting temperature of 690℃~750℃ and a cooling rate of 50~90mm / min.
3. The heat treatment process for homogenizing 6000 series aluminum alloys based on icosahedral quasi-crystalline dispersed phase regulation according to claim 1, characterized in that, In S01, the aluminum alloy ingot contains 0.8-3.2 wt.% Mg, 0.2-1.2 wt.% Si, 0.4-1.8 wt.% Cu, and 0.5-1.5 wt.% Mn, with the balance being Al and unavoidable impurities.
4. An aluminum alloy obtained by a heat treatment process for homogenizing 6000 series aluminum alloy based on icosahedral quasicrystalline dispersed phase control according to any one of claims 1 to 3.
5. The aluminum alloy according to claim 4, characterized in that, In aluminum alloys, the size of the dispersed phase with an icosahedral quasicrystalline structure is 10-20 nm, and it is highly coherent with the matrix.
6. The aluminum alloy according to claim 4, characterized in that, The yield strength is 489.3–500 MPa, the tensile strength is 531.0–542.1 MPa, and the elongation is 11.3–12.3%.
7. The application of the aluminum alloy according to claim 4 in automobiles.
8. An automotive component, characterized in that, It is prepared from the aluminum alloy described in claim 4.