Multi-stage aging method for inhibiting parking effect of 6013 wrought aluminum alloy and improving aging strengthening effect

Abstract

The invention belongs to the technical field of aluminum alloys, and discloses a multi-stage aging method for inhibiting the parking effect of a 6013 wrought aluminum alloy and improving the aging strengthening effect. According to the multi-stage aging method, the extruded 6013 wrought aluminum alloy plate is subjected to solution treatment, pre-aging treatment, standing treatment, regression aging treatment and final aging treatment; the heat preservation temperature of the pre-aging treatment ranges from 100 DEG C to 160 DEG C, and the heat preservation time ranges from 10 min to 240 min; the heat preservation temperature of the regression aging treatment ranges from 200 DEG C to 240 DEG C, and the heat preservation time ranges from 10 min to 60 min; the final aging heat preservation temperature is 170-190 DEG C, and the heat preservation time is 4-10 h. According to the method, the alloy aging precipitation process is improved, formation of natural aging clusters is reduced, precipitation of a peak aging state beta ''phase is promoted, the adverse effect of a parking effect is inhibited, the aging strengthening effect is improved, and the mechanical property of the 6013 wrought aluminum alloy is remarkably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of nonferrous metals, and in particular relates to a multi-stage aging method for suppressing the parking effect of 6013 deformed aluminum alloy and improving the aging strengthening effect. Background Art

[0002] 6013 deformed aluminum alloy belongs to Al-Mg-Si alloy, which is a typical heat-treatable and strengthened aluminum alloy. It has the advantages of high strength, good corrosion resistance, good thermal conductivity, excellent anodizing effect, good extrusion forming, etc. It is widely used in various fields such as construction, shipbuilding and automobile manufacturing. In addition, it is also widely used in the field of 3C electronic products such as mobile phones, computers and other electronic communication products.

[0003] In the extrusion production process of 6013 deformed aluminum alloy, after the cast rod is extruded into a plate and quenched online, it needs to be immediately artificially aged to better improve the material strength. However, in the actual production process, the alloy plate usually needs to be cut into a suitable size after quenching before being framed for aging. At the same time, due to the limitations of the aging furnace, the extruded alloy usually cannot be immediately arranged for artificial aging heat treatment. The alloy usually needs to be parked for a period of time before aging treatment. During the room temperature parking process, a large number of supersaturated solute atoms in the alloy gather to form clusters with the help of quenching vacancies. Such clusters formed at room temperature will have an adverse effect on the subsequent artificial aging process, hindering the precipitation of the main strengthening phase β" phase during the artificial aging process, thereby reducing the hardness and strength of the peak aged alloy. This performance reduction caused by room temperature parking is called "parking effect" in the industry.

[0004] By introducing a pre-aging process after online quenching, the room temperature parking effect can be effectively improved, so that the strength of the alloy can be close to the strength when artificial aging is directly performed without parking. In addition, pre-deformation including pre-stretching and rolling can also improve the room temperature parking effect, but it will change the size of the alloy and cannot meet the requirements of flatness and other subsequent processing technologies. Chinese invention patent CN114369777B discloses a multi-stage multi-rate heat treatment process, which promotes the precipitation of strengthening phases by adjusting the holding time, temperature and heating rate of the heat treatment, and can effectively avoid the occurrence of the room temperature parking effect of 6 series aluminum alloys. Chinese invention patent application CN112941433A discloses an aging process for improving the parking effect of 6082 aluminum alloy. The invention adopts different heating rates during the artificial aging process to regulate the aging precipitation process, thereby improving the mechanical properties of 6082 aluminum alloy. However, its heating and holding time is relatively long, which is not conducive to improving the production efficiency of enterprises.

[0005] Chinese invention patent application CN 116497244A discloses a method for preparing a 6-series aluminum alloy with high strength and low parking effect, that is, when the alloy is cooled online after extrusion, the artificial rapid cooling is stopped when the surface temperature of the profile cools to 210±10℃, and then it is naturally cooled slowly to room temperature; this method can effectively reduce the adverse effects of the room temperature parking effect, but the refined control process of its previous process is not easy to achieve in the production process, and the quenching medium needs to be additionally treated, which increases the production cost. Chinese patent application CN 111155002A proposes Sn microalloying and subsequent aging process, which can effectively inhibit the negative effects of natural aging and improve the paint response, but this process is only applicable to automotive aluminum alloys produced by rolling. The addition of new elements will change the alloy composition and increase the production cost, and has limited guiding significance for the actual production of deformed 6013 aluminum alloys for electronic products produced by extrusion.

[0006] The above-mentioned prior art explores different methods and heat treatment processes for improving the room temperature parking effect of 6 series aluminum alloys, and can improve the adverse effects of the room temperature parking effect to a certain extent, so that the alloy performance is close to the performance after direct artificial aging without parking, but their process flow is complicated, which is not conducive to the improvement of production efficiency in the actual production process of the enterprise, or the mechanical properties of the alloy need to be further improved. Most of the existing technologies only consider the suppression of the parking effect, but fail to achieve the simultaneous improvement and enhancement of the strengthening effect on this basis. The present invention provides a multi-stage aging method, which can simultaneously improve the alloy aging strengthening effect on the basis of suppressing the room temperature parking effect of 6013 deformed aluminum alloy, and the overall aging time is shortened, and the production efficiency is improved. Summary of the invention

[0007] The purpose of the present invention is to provide a multi-stage aging method for suppressing the parking effect of 6013 type deformed aluminum alloy and improving the aging strengthening effect. The present invention improves the alloy aging precipitation process by heat preservation at different temperatures, promotes the precipitation of the main strengthening phase β" phase, and suppresses the parking effect of 6013 deformed aluminum alloy.

[0008] The technical solution of the present invention is:

[0009] A multi-stage aging method for suppressing the parking effect of 6013 deformed aluminum alloy and improving the aging strengthening effect comprises the following steps:

[0010] (1) subjecting an extruded 6013 deformed aluminum alloy sheet to a solid solution treatment to obtain a supersaturated solid solution sheet;

[0011] (2) subjecting the supersaturated solid solution plate to a pre-aging treatment to obtain a pre-aging plate;

[0012] (3) Parking the pre-aged plate;

[0013] (4) subjecting the parked plates to a return aging treatment;

[0014] (5) The regressive aging plate is subjected to aging insulation, and then taken out for air cooling to complete the final aging.

[0015] The 6013 deformable aluminum alloy refers to a deformable aluminum alloy with a grade of 6013, and its composition is, by element mass percentage, silicon: 0.6-1.0%, magnesium: 0.8-1.2%, copper: 0.6-1.1%, manganese: 0.2-0.8%, iron: ≤0.5%, zinc ≤0.25%, chromium: ≤0.1%, titanium: ≤0.1%, and the balance is aluminum.

[0016] The extruded 6013 deformed aluminum alloy sheet described in step (1) refers to the 6013 deformed aluminum alloy obtained by casting an ingot, homogenizing, hot extruding, online quenching, and sawing.

[0017] The solution treatment in step (1) refers to heat preservation followed by cooling; the heat preservation temperature is 520-560°C and the heat preservation time is 20-60 minutes; the cooling refers to cooling with water, specifically, directly placing the plate in water for cooling after heat preservation. The cooling rate is ≥500°C / s. The water is room temperature water.

[0018] The pre-aging treatment in step (2) refers to heat preservation followed by air cooling; the heat preservation temperature is 100-160°C and the heat preservation time is 10-240 minutes. Air cooling refers to taking out and placing in air for cooling.

[0019] The parking time in step (3) is 1 to 9 days, preferably 6 to 8 days. The parking treatment is a natural parking treatment, specifically refers to parking in a cool place, such as: parking in a cool place indoors.

[0020] The aging treatment described in step (4) refers to heat preservation before cooling; the heat preservation temperature is 200-240°C, the heat preservation time is 10-60 minutes, preferably 20-40 minutes; the cooling refers to cooling with water, specifically refers to directly placing the plate in water for cooling after heat preservation. The cooling rate is greater than 500°C / s. The water is room temperature water.

[0021] The temperature of the aging insulation in step (5) is 170-190° C., and the insulation time is 4 to 10 hours, preferably 4 to 6 hours.

[0022] The multi-stage aging method specifically comprises the following steps:

[0023] (1) placing an extruded 6013 deformed aluminum alloy sheet in a heat treatment furnace for heat preservation, and then rapidly cooling the sheet to obtain a supersaturated solid solution sheet;

[0024] (2) placing the supersaturated solid solution plate in an aging furnace for heat preservation, and then taking it out for air cooling, thereby completing the pre-aging treatment;

[0025] (3) Place the pre-aged sheet in a cool place indoors to complete the parking process;

[0026] (4) The parked plate is placed in an aging furnace for heat preservation, and then taken out for rapid cooling, thereby completing the regression aging treatment;

[0027] (5) Place the retrograde aging plate in the aging furnace to keep it warm, then take it out and air cool it to complete the final aging.

[0028] The air cooling refers to cooling to room temperature.

[0029] The alloy prepared by the present invention is a 6013 deformed aluminum alloy for 3C electronic product structural parts.

[0030] In order to better understand the method of the present invention, the principle of aging strengthening of aluminum alloy is described as follows in combination with the strengthening mechanism of heat-treatable strengthening aluminum alloy and the aging precipitation process of Al-Mg-Si (Cu) alloy:

[0031] For 6xxx series Al-Mg-Si-Cu alloys, solution quenching treatment is carried out during the production process (usually online quenching treatment in extrusion process). Since the solubility of Mg, Si and Cu elements in the aluminum matrix is ​​17.4%, 1.65% and 5.7% at high temperature, and only 1%, 0.05% and 0.1% at room temperature, the alloy will reduce the total energy of the system to make it tend to equilibrium by forming precipitation phases. The precipitation phase and the strain field it induces will hinder the movement of dislocations during plastic deformation, increase the difficulty of plastic deformation of the alloy, and thus improve the strength of the alloy. For 6013 alloy containing Cu, its precipitation sequence is: supersaturated solid solution (SSSS) → solute atom cluster area → GP area / pre-β" → β" (the main strengthening phase in the peak aged alloy), L / S / C / QP / QC (precursor phase of Q' or Q) → β', Q' → β, Q (stable phase of over-aged state).

[0032] When 6013 alloy is used as a structural part of 3C electronic products, it is usually used in the peak aging state. Its peak aging yield strength can reach more than 345MPa, and its tensile strength can exceed 390MPa. Its main strengthening phase in the peak aging state is β" phase. Solution quenching causes a large number of supersaturated solute atoms and quenching vacancies to appear in the alloy matrix. The alloy is in an unstable supersaturated state and has a tendency to spontaneously dissolve and decompose. Natural aging clusters will be formed at room temperature. The clusters have limited effect on matrix strengthening and will affect the nucleation of β" phase in the subsequent artificial aging process, reducing the performance of the alloy. Under the same other conditions, the peak aging yield strength of the alloy after parking is reduced to below 320MPa, and the tensile strength is reduced to 360MPa.

[0033] The invention provides a multi-stage aging method for inhibiting the parking effect of a 6013 deformed aluminum alloy and improving the aging strengthening effect. The basic mechanism is as follows: after solution quenching, a large number of supersaturated solute atoms and quenching vacancies exist in the alloy matrix, which is in a thermodynamically unstable state and has a tendency to spontaneously transform to a stable state; after pre-aging, the supersaturated solute atoms in the alloy diffuse with the help of quenching vacancies under the energy provided by pre-aging, forming a large number of pre-aging clusters with a Mg:Si ratio close to 1:1, which are recorded as cluster 1; in the subsequent parking process, the remaining solute atoms in the alloy are consumed in large quantities during the pre-aging process, and the concentration is low. As the natural aging proceeds, a small number of natural aging clusters are formed, which are recorded as cluster 2; during regression aging, cluster 1 in the alloy has a Mg:Si ratio close to 1:1, which is in contact with the main strengthening phase β" phase (composed of Mg 5 Si 6 ) is close to the nucleation site of β" phase during the regression aging process, and it grows continuously to form an early β" phase, which is recorded as pre-β" phase; cluster 2 is unstable and quickly decomposes into solute atoms during the high-temperature regression aging process, and diffuses and nucleates to form an early pre-β" phase; in the subsequent artificial aging process, the pre-β" phase formed during regression aging grows continuously, and its size tends to be stable at the peak aging state, and the strengthening effect on the alloy is optimal.

[0034] The present invention improves the alloy precipitation process, generates a large number of strengthening precipitation phases, effectively suppresses the alloy parking effect, and improves the comprehensive mechanical properties of the alloy.

[0035] Compared with the existing heat treatment process, the present invention has the following advantages and beneficial effects:

[0036] 1. The present invention effectively suppresses the parking effect of 6013 deformed aluminum alloy through a multi-stage aging method, and achieves simultaneous improvement and further enhancement of the mechanical properties of the alloy.

[0037] 2. The present invention shortens the time for subsequent artificial aging to reach peak aging through pre-aging and regression aging processes, thereby improving production efficiency and reducing energy consumption.

[0038] 3. The present invention does not require the addition of new equipment, but only requires adjusting the production steps of the existing production line to achieve the improvement of alloy performance, and is easy to achieve mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic diagram of the conventional extruded aluminum alloy heat treatment process flow in Comparative Example 2;

[0040] Figure 2 The tensile fracture morphology of the alloy in Comparative Example 1;

[0041] Figure 3 The tensile fracture morphology of the alloy in Comparative Example 2;

[0042] Figure 4 It is a schematic flow chart of the multi-stage aging method of the present invention;

[0043] Figure 5 The tensile fracture morphology of the alloy in Example 1;

[0044] Figure 6 Comparison of stress-strain curves of the alloys in Comparative Examples 1 to 5 and Examples 1 to 4. DETAILED DESCRIPTION

[0045] The present invention is described in detail below in conjunction with specific comparative examples and embodiments, but the embodiments of the present invention are not limited thereto.

[0046] In the embodiment, the extruded 6013 deformed aluminum alloy plate refers to the 6013 deformed aluminum alloy being obtained by casting an ingot, homogenizing, hot extruding, online quenching, and sawing. The ingot size is Φ160mm×800mm; the homogenizing heat treatment temperature is 550-580℃, and the time is 6-10h; the hot extrusion temperature is 520-550℃, and the extrusion outlet temperature is 500-520℃; the cooling method used for online quenching is water cooling; the plate size after sawing is 180mm×90mm×9mm.

[0047] In order to better illustrate the implementation effect of the present invention, an ideal heat treatment process without parking state is taken as comparative example 1, a heat treatment process for producing extruded 6013 deformed aluminum alloy in actual production is taken as comparative example 2, a process without pre-aging, only regression aging and final aging is taken as comparative example 3, a process without regression aging, only pre-aging and final aging is taken as comparative example 4, and a process without final aging, only pre-aging and regression aging is taken as comparative example 5.

[0048] Comparative Example 1

[0049] In this comparative example, extruded 6013 deformed aluminum alloy plates (specifically, 6013 deformed aluminum alloy is obtained by casting billets, homogenizing, hot extruding, online quenching, and sawing) are used as raw materials and are processed using an ideal non-parking aging process.

[0050] The composition of the 6013 deformed aluminum alloy is measured by ARL3460 direct reading spectrometer, and the percentage of elements is as follows: silicon: 0.7%; magnesium: 0.9%; copper: 0.7%; iron: 0.1%; manganese: 0.2%; and the balance is aluminum.

[0051] The heat treatment process in this comparative example specifically includes the following steps:

[0052] (1) The 6013 alloy plate obtained by extrusion was placed in a muffle furnace at 540°C for 45 min and then taken out for water quenching to perform a re-solution quenching treatment;

[0053] (2) The plate after solution quenching is placed in an aging furnace at 185°C for 10 hours and then taken out for air cooling to complete the artificial aging treatment.

[0054] The present invention conducts mechanical property tests on an MTS Exceed E45 electronic universal testing machine according to the national standard GB / T 228.1. The test samples are processed into dumbbell shapes by cutting machines and CNC lathes according to the current national standard GB / T16865-2023, and the upper and lower surfaces are polished with 400-mesh sandpaper to eliminate the influence of defects on the experimental results. In this test, each group of alloys is tested 3 times at a tensile speed of 3mm / min and room temperature (25°C), and the stress-strain curves are recorded to obtain performance data. The data are recorded in Table 1 after taking the average; the tensile fracture morphology is photographed by a TESCAN MIRA3 scanning electron microscope to analyze its structural characteristics and fracture form; Figure 2 This is a typical tensile fracture morphology of Comparative Example 1.

[0055] The alloy yield strength measured in this comparative example is 348MPa, the tensile strength is 392MPa, and the elongation at break is 13.8%. Figure 2 It can be seen that there are a large number of dimples on the alloy fracture surface, accompanied by a small amount of tearing edges formed by the expansion of microcracks, showing obvious plastic fracture. After the alloy is treated by this process, the dimple size is uniform and the cross section of the tearing edge is rough, indicating that the alloy absorbs a large amount of energy during the fracture process and the alloy has excellent performance.

[0056] Comparative Example 2

[0057] The alloy raw materials used in this comparative example are exactly the same as those in comparative example 1, and the plates used are obtained by extruding the same billet.

[0058] This comparative example uses extruded sheet as raw material and uses the heat treatment process used in the actual production process of the enterprise for processing. Its process flow is similar to that of comparative example 1, except that a parking process is added. The conventional process flow of this comparative example is as follows Figure 1 shown.

[0059] The heat treatment process in this comparative example specifically includes the following steps:

[0060] (1) The 6013 alloy plate obtained by extrusion was placed in a muffle furnace at 540°C for 45 min and then taken out for water quenching to perform a re-solution quenching treatment;

[0061] (2) placing the alloy plate after solution quenching in a cool place indoors for 7 days;

[0062] (3) The parked alloy plate is placed in an aging furnace at 185°C for 10 hours and then taken out for air cooling to complete the artificial aging treatment.

[0063] Similarly, the treated alloy plates were subjected to tensile testing and tensile fracture morphology analysis, and the mechanical properties data were recorded in Table 1; Figure 3 This is a typical tensile fracture morphology of Comparative Example 2.

[0064] Compared with Comparative Example 1, the yield strength and tensile strength of the alloy in this comparative example are greatly reduced, with the yield strength reduced to 315MPa and the tensile strength reduced to 360MPa, showing a significant room temperature "parking effect". After solutionizing and parking at room temperature (7 days), the yield strength decreased by 9.5% and the tensile strength decreased by 8.2%. Figure 3 It can be seen that the alloy fracture is also composed of a large number of dimples and a small number of tearing edges, which is also a typical plastic fracture. Compared with comparative example 1, the dimple size distribution is uneven and larger, and the alloy yield strength is low; the number of tearing edges is smaller, and the degree of plastic deformation before fracture is greater.

[0065] Example 1

[0066] The alloy raw materials used in this embodiment are the same as those in Comparative Example 1, and the plates used are obtained by extruding the same billet.

[0067] This embodiment uses extruded sheet as raw material and uses a multi-stage aging method for treatment. The process flow chart is as follows: Figure 4 shown.

[0068] In this embodiment, a multi-stage aging method for suppressing the parking effect of 6013 deformed aluminum alloy and improving the aging strengthening effect includes the following steps:

[0069] (1) The 6013 alloy plate obtained by extrusion was placed in a muffle furnace at 540°C for 45 min and then taken out for water quenching to perform a re-solution quenching treatment;

[0070] (2) The quenched alloy plate is placed in an aging furnace at 100°C for 1 hour and then taken out for air cooling to complete the pre-aging treatment;

[0071] (3) placing the pre-aged alloy plate at room temperature for 7 days;

[0072] (4) Place the plate in a 220°C aging furnace for 0.5 h and then take it out for water cooling to complete the regression treatment;

[0073] (5) Place the plate in an aging furnace at 185°C for 5 hours and then take it out for air cooling to complete the final artificial aging treatment.

[0074] The treated alloy plates were also subjected to tensile tests and tensile fracture morphology analysis, and the mechanical properties data were recorded in Table 1. Figure 5 This is a typical tensile fracture morphology of Example 1.

[0075] from Figure 5 It can be seen that after the multi-stage aging method of the present invention, the alloy fracture is still composed of a large number of dimples and a small number of tear edges. Unlike Comparative Example 1, the dimple size is smaller and its distribution is more uniform, indicating that it absorbs more energy during the plastic fracture process and has better strength performance. In addition, the tear edges are fewer and rougher, indicating that a large amount of energy is still absorbed at the location of the microcracks during the plastic deformation process and sufficient deformation occurs.

[0076] The yield strength of the alloy prepared in this embodiment is 351MPa, the tensile strength is 391MPa, and the elongation at break is 15.8%. Compared with Comparative Example 2, the yield strength is increased by 11.4%, the tensile strength is increased by 8.6%, and the alloy parking effect is significantly suppressed. Compared with Comparative Example 1, the alloy has similar yield and tensile strengths, and the elongation at break is increased by 14.5%. By comparing with Comparative Examples 1 and 2, it is shown that this method can achieve simultaneous improvement and further enhancement of the aging strengthening effect while suppressing the alloy parking effect.

[0077] Example 2

[0078] The alloy raw materials used in this embodiment are exactly the same as those in Comparative Example 1, and the plates used are obtained by extruding the same billet.

[0079] A multi-stage aging method for suppressing the parking effect of 6013 deformed aluminum alloy and improving the aging strengthening effect comprises the following steps:

[0080] (1) The 6013 alloy plate obtained by extrusion was placed in a muffle furnace at 540°C for 45 min and then taken out for water quenching to perform a re-solution quenching treatment;

[0081] (2) The quenched alloy plate is placed in an aging furnace at 160°C for 15 minutes and then taken out for air cooling to complete the pre-aging treatment;

[0082] (3) placing the pre-aged alloy plate at room temperature for 7 days;

[0083] (4) Place the plate in a 220°C aging furnace for 0.5 h and then take it out for water cooling to complete the regression treatment;

[0084] (5) Place the plate in an aging furnace at 185°C for 5 hours and then take it out for air cooling to complete the final artificial aging treatment.

[0085] Similarly, the treated alloy plate was subjected to tensile test and tensile fracture morphology analysis, and the mechanical property data were recorded in Table 1. The fracture morphology was not significantly different from that of Example 1.

[0086] The yield strength of the alloy prepared in this embodiment is 358MPa, the tensile strength is 390MPa, and the elongation at break is 15.3%. Compared with Comparative Example 2, the yield strength is increased by 13.7%, the tensile strength is increased by 8.3%, and the alloy parking effect is significantly suppressed. Compared with Comparative Example 1, the alloy has similar tensile strength, the yield strength is increased by 2.9%, and the elongation at break is increased by 10.9%. By comparing with Comparative Examples 1 and 2, it is shown that this method can suppress the alloy parking effect while achieving simultaneous improvement and further improvement of the aging strengthening effect.

[0087] Example 3

[0088] The alloy raw materials used in this embodiment are the same as those in Comparative Example 1, and the plates used are obtained by extruding the same billet.

[0089] In this embodiment, a multi-stage aging method for suppressing the parking effect of 6013 deformed aluminum alloy and improving the aging strengthening effect specifically includes the following steps:

[0090] (1) The 6013 alloy plate obtained by extrusion was placed in a muffle furnace at 540°C for 45 min and then taken out for water quenching to perform a re-solution quenching treatment;

[0091] (2) The quenched alloy plate is placed in an aging furnace at 100°C for 1 hour and then taken out for air cooling to complete the pre-aging treatment;

[0092] (3) placing the pre-aged alloy plate at room temperature for 7 days;

[0093] (4) Place the parked plate in a 200°C aging furnace for 0.5 h, then take it out and water cool it to complete the regression treatment;

[0094] (5) Place the plate in an aging furnace at 185°C for 6 hours and then take it out for air cooling to complete the final artificial aging treatment.

[0095] The treated alloy plate was subjected to tensile test and tensile fracture morphology analysis, and the mechanical property data were recorded in Table 1. The fracture morphology was not significantly different from that of Example 1.

[0096] The yield strength of the alloy prepared in this embodiment is 356MPa, the tensile strength is 392MPa, and the elongation at break is 15.9%. Compared with Comparative Example 2, the yield strength is increased by 13.0%, the tensile strength is increased by 8.9%, and the alloy parking effect is significantly suppressed. Compared with Comparative Example 1, the alloy has similar tensile strength, the yield strength is increased by 2.3%, and the elongation at break is increased by 15.2%. By comparing with Comparative Examples 1 and 2, it is shown that this method can achieve simultaneous improvement and further improvement of the aging strengthening effect while suppressing the alloy parking effect.

[0097] Example 4

[0098] The alloy raw materials used in this embodiment are the same as those in Comparative Example 1, and the plates used are obtained by extruding the same billet.

[0099] In this embodiment, a multi-stage aging method for suppressing the parking effect of 6013 deformed aluminum alloy and improving the aging strengthening effect specifically includes the following steps:

[0100] (1) The 6013 alloy plate obtained by extrusion was placed in a muffle furnace at 540°C for 45 min and then taken out for water quenching to perform a re-solution quenching treatment;

[0101] (2) The quenched alloy plate is placed in an aging furnace at 160°C for 15 minutes and then taken out for air cooling to complete the pre-aging treatment;

[0102] (3) placing the pre-aged alloy plate at room temperature for 7 days;

[0103] (4) Place the plate in a 240°C aging furnace for 0.5 h and then take it out for water cooling to complete the regression treatment;

[0104] (5) Place the plate in an aging furnace at 185°C for 4 hours and then take it out for air cooling to complete the final artificial aging treatment.

[0105] The treated alloy plate was subjected to tensile test and tensile fracture morphology analysis, and the mechanical property data were recorded in Table 1. The fracture morphology was not significantly different from that of Example 1.

[0106] The yield strength of the alloy prepared in this embodiment is 354MPa, the tensile strength is 395MPa, and the elongation at break is 15.4%. Compared with Comparative Example 2, the yield strength is increased by 12.4%, the tensile strength is increased by 9.7%, and the alloy parking effect is significantly suppressed. Compared with Comparative Example 1, the tensile strength and yield strength of the alloy are slightly improved, and the elongation at break is increased by 11.6%. By comparing with Comparative Examples 1 and 2, it is shown that this method can achieve simultaneous improvement and further improvement of the aging strengthening effect while suppressing the alloy parking effect.

[0107] Comparative Example 3

[0108] The alloy raw materials used in this comparative example are exactly the same as those in comparative example 1, and the plates used are obtained by extruding the same billet.

[0109] In this comparative example, extruded plates are used as raw materials, and are processed by a process without pre-aging, and only regression aging and final aging. The process flow is similar to that of Example 1, except that the pre-aging process is reduced.

[0110] The heat treatment process in this comparative example specifically includes the following steps:

[0111] (1) The 6013 alloy plate obtained by extrusion was placed in a muffle furnace at 540°C for 45 min and then taken out for water quenching to perform a re-solution quenching treatment;

[0112] (2) Place the alloy plate after solution quenching in a cool place indoors for 7 days;

[0113] (3) The parked alloy plate is placed in an aging furnace at 220°C for 30 minutes and then taken out for water cooling to complete the regression aging treatment;

[0114] (4) Place the plate in an aging furnace at 185°C for 6 hours and then take it out for air cooling to complete the final artificial aging treatment.

[0115] The treated alloy plates were subjected to tensile tests, and the mechanical property data were recorded in Table 1.

[0116] The yield strength of the alloy prepared in this comparative example is reduced to 332MPa, the tensile strength is reduced to 382MPa, and the elongation at break is 14.6%. Compared with comparative example 2, the yield strength and tensile strength of the alloy are significantly increased, with the yield strength increased by 5.4% and the tensile strength increased by 6.1%, indicating that the parking effect of the alloy can be suppressed to a certain extent only by the regression aging process. Compared with comparative example 1, the yield strength of the alloy is reduced by 4.6%, and the tensile strength is reduced by 2.6%, and the ideal alloy performance is not achieved. Compared with Examples 1 to 4, the yield strength, tensile strength and elongation of the alloy are significantly reduced, proving that only under the steps and conditions of the present invention can it be guaranteed that while effectively suppressing the parking effect, the aging strengthening effect can be simultaneously improved and further enhanced.

[0117] Comparative Example 4

[0118] The alloy raw materials used in this comparative example are exactly the same as those in comparative example 1, and the plates used are obtained by extruding the same billet.

[0119] In this comparative example, extruded plates are used as raw materials, and are processed by a process without regression aging, and only pre-aging and final aging are performed. The process flow is similar to that of Example 1, except that the regression aging process is reduced.

[0120] The heat treatment process in this comparative example specifically includes the following steps:

[0121] (1) The 6013 alloy plate obtained by extrusion was placed in a muffle furnace at 540°C for 45 min and then taken out for water quenching to perform a re-solution quenching treatment;

[0122] (2) The alloy plate after solution quenching is placed in an aging furnace at 160°C for 15 minutes and then taken out for air cooling to complete the pre-aging treatment;

[0123] (3) placing the pre-aged alloy plate in a cool place indoors for 7 days;

[0124] (4) The plate is placed in an aging furnace at 185°C for 6 hours and then taken out for air cooling to complete the final artificial aging treatment.

[0125] The treated alloy plates were subjected to tensile tests, and the mechanical property data were recorded in Table 1.

[0126] The yield strength of the alloy prepared in this comparative example is reduced to 335MPa, the tensile strength is reduced to 379MPa, and the elongation at break is 14.2%. Compared with comparative example 2, the yield strength and tensile strength of the alloy are significantly increased, with the yield strength increased by 6.3% and the tensile strength increased by 5.3%, indicating that the parking effect of the alloy can be suppressed to a certain extent only by the regression aging process. Compared with comparative example 1, the yield strength of the alloy is reduced by 3.7%, and the tensile strength is reduced by 3.3%, and the alloy performance in the ideal state is not achieved. Compared with Examples 1 to 4, the yield strength, tensile strength and elongation of the alloy are significantly reduced, proving that only under the steps and conditions of the present invention can it be guaranteed that while effectively suppressing the parking effect, the aging strengthening effect can be simultaneously improved and further enhanced.

[0127] Comparative Example 5

[0128] The alloy raw materials used in this comparative example are the same as those in comparative example 1, and the plates used are obtained by extruding the same billet.

[0129] In this comparative example, extruded plates are used as raw materials, and are processed by a process without final aging, and only pre-aging and regression aging are performed. The process flow is similar to that of Example 1, except that the final aging process is reduced.

[0130] The heat treatment process in this comparative example specifically includes the following steps:

[0131] (1) The 6013 alloy plate obtained by extrusion was placed in a muffle furnace at 540°C for 45 min and then taken out for water quenching to perform a re-solution quenching treatment;

[0132] (2) The quenched alloy plate is placed in an aging furnace at 160°C for 15 minutes and then taken out for air cooling to complete the pre-aging treatment;

[0133] (3) placing the pre-aged alloy plate at room temperature for 7 days;

[0134] (4) Place the plate in a 220°C aging furnace for 0.5 h and then take it out for water cooling to complete the aging process.

[0135] The treated alloy plates were subjected to tensile tests, and the mechanical property data were recorded in Table 1.

[0136] The yield strength of the alloy prepared in this comparative example is reduced to 256MPa, the tensile strength is reduced to 347MPa, and the elongation at break is 21.7%. Compared with comparative example 2, the yield strength and tensile strength of the alloy are significantly reduced, with the yield strength reduced by 18.7% and the tensile strength reduced by 3.6%, indicating that the parking effect of the alloy cannot be suppressed by only pre-aging and regression aging processes. Compared with comparative example 1, the yield strength of the alloy is reduced by 26.4%, and the tensile strength is reduced by 11.5%, and even the alloy performance in actual production is not achieved. Compared with Examples 1 to 4, the yield strength and tensile strength of the alloy are significantly reduced, proving that only under the steps and conditions of the present invention can it be guaranteed that while effectively suppressing the parking effect, the aging strengthening effect can be simultaneously improved and further enhanced.

[0137] Table 1 shows the mechanical properties of the alloys in Examples 1-4 and Comparative Examples 1-2.

[0138] Table 1 Mechanical properties of alloys in Examples 1-4 and Comparative Examples 1-2

[0139]

[0140] As shown in Table 1, compared with Comparative Example 1, the yield strength and tensile strength of the alloys in Examples 1 to 4 are improved to varying degrees, which indicates that the multi-stage aging method of the present invention for suppressing the parking effect of 6013 deformed aluminum alloy and improving the aging strengthening effect achieves simultaneous improvement and further improvement of the aging strengthening effect; compared with Comparative Example 2, the yield strength of the alloys in Examples 1 to 4 is greatly improved, and the general improvement is more than 11%, which indicates that the multi-stage aging method of the present invention for suppressing the parking effect of 6013 deformed aluminum alloy and improving the aging strengthening effect significantly suppresses the parking effect of the alloy.

[0141] Figure 6 The stress-strain curves of the alloys in comparative examples 1 to 5 and examples 1 to 4 are shown. It can be seen that compared with comparative example 1, the tensile strength and yield strength of examples 1 to 4 are significantly improved; compared with comparative example 2, the tensile strength and yield strength of the alloy are slightly improved, indicating that the present invention effectively suppresses the parking effect of 6013 deformed aluminum alloy while achieving simultaneous improvement and further improvement of the aging strengthening effect. Comparative examples 3 to 5, compared with examples 1 to 4, only under the steps and conditions of the present invention can the parking effect be effectively suppressed while achieving simultaneous improvement and further improvement of the aging strengthening effect.

[0142] The present invention suppresses the parking effect of the 6013 deformed aluminum alloy by reasonably controlling the heat treatment aging process of the material, and further improves the strength performance of the 6013 deformed aluminum alloy.

[0143] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A multi-stage aging method for suppressing the parking effect of 6013 deformed aluminum alloy and improving the aging strengthening effect, characterized in that: The following steps are involved: (1) subjecting an extruded 6013 deformed aluminum alloy sheet to a solid solution treatment to obtain a supersaturated solid solution sheet; (2) subjecting the supersaturated solid solution plate to a pre-aging treatment to obtain a pre-aging plate; (3) Parking the pre-aged plate; (4) subjecting the parked plates to a return aging treatment; (5) The regressive aging plate is subjected to aging and heat preservation, and then taken out for air cooling to complete the final aging; The solution treatment in step (1) refers to heat preservation followed by cooling; the heat preservation temperature is 520-560° C., and the heat preservation time is 20-60 min; the cooling refers to cooling by water; The pre-aging treatment in step (2) refers to heat preservation followed by air cooling; the heat preservation temperature is 100 to 160° C., and the heat preservation time is 10 to 240 minutes; The parking time in step (3) is 1 to 9 days; The aging treatment in step (4) refers to first keeping warm and then cooling; the keeping warm temperature is 200-240°C, and the keeping warm time is 10-60 minutes; the cooling refers to cooling with water; The aging insulation temperature in step (5) is 170-190° C., and the insulation time is 4 to 10 hours.

2. The multi-stage aging method for suppressing the parking effect of 6013 deformed aluminum alloy and improving the aging strengthening effect according to claim 1, characterized in that: The pre-aging temperature is 100-110°C, and the holding time is 30-240min; the pre-aging temperature is 150-160°C, and the holding time is 10-60min; the pre-aging temperature is 110-120°C, and the holding time is 25-200min; the pre-aging temperature is 120-130°C, and the holding time is 20-160min; the pre-aging temperature is 130-140°C, and the holding time is 20-120min; the pre-aging temperature is 140-150°C, and the holding time is 15-90min; The parking time is 6 to 8 days; The temperature of the regression aging in step (4) is 200-240° C., and the insulation time is 20-40 min; The temperature of the heat preservation aging in step (5) is 180-190° C., and the heat preservation time is 4-6 hours.

3. The multi-stage aging method for suppressing the parking effect of 6013 deformed aluminum alloy and improving the aging strengthening effect according to claim 1, characterized in that: The 6013 deformable aluminum alloy refers to a deformable aluminum alloy with a grade of 6013, and its composition is, by element mass percentage, silicon: 0.6-1.0%, magnesium: 0.8-1.2%, copper: 0.6-1.1%, manganese: 0.2-0.8%, iron: ≤0.5%, zinc ≤0.25%, chromium: ≤0.1%, titanium: ≤0.1%, and the balance is aluminum; The extruded 6013 deformed aluminum alloy sheet described in step (1) refers to the 6013 deformed aluminum alloy obtained by casting an ingot, homogenizing, hot extruding, online quenching, and sawing.

4. The multi-stage aging method for suppressing the parking effect of 6013 deformed aluminum alloy and improving the aging strengthening effect according to claim 1, characterized in that: The cooling in step (1) refers to cooling with water, specifically, directly placing the plate in water for cooling after heat preservation; the water is room temperature water; In step (2), air cooling means taking out and placing in air for cooling.

5. The multi-stage aging method for suppressing the parking effect of 6013 deformed aluminum alloy and improving the aging strengthening effect according to claim 1, characterized in that: The parking process in step (3) is natural parking; The cooling in step (4) refers to cooling with water, specifically, directly placing the plate in water for cooling after heat preservation, and the water is room temperature water.

6. The multi-stage aging method for suppressing the parking effect of 6013 deformed aluminum alloy and improving the aging strengthening effect according to claim 5, characterized in that: The parking process described in step (3) refers to parking in a cool place.

7. A 6013 deformed aluminum alloy obtained by the method according to any one of claims 1 to 6.

8. The use of 6013 deformed aluminum alloy according to claim 7, characterized in that: The 6013 deformed aluminum alloy is used for structural parts of 3C electronic products.

Images