Aluminum alloy profile with mixed crystal heterostructure characteristics and preparation method

Abstract

The present application relates to the technical field of metal material preparation, in particular to an aluminum alloy profile with mixed crystal heterogeneous structure characteristics and a preparation method. The preparation method of the aluminum alloy profile with mixed crystal heterogeneous structure characteristics comprises the following steps: melting, using pure Al, aluminum intermediate alloy containing TiB2 and TiC particles, and melting the aluminum intermediate alloy and pure metal at a temperature of 800-850 DEG C for the purpose of adding aluminum intermediate alloy required for manufacturing different series of aluminum alloy profiles; casting, casting the alloy after melting at a temperature of 720-750 DEG C. The present application has the beneficial effects that: the preparation method can prepare coarse and fine crystal mixed grains by adding a small amount of TiB2 and TiC particles in the preparation of aluminum alloy, and the coarse and fine grain ratio can be adjusted and controlled after hot extrusion and solid solution heat treatment, and the alloy with the mixed crystal heterogeneous structure characteristics can simultaneously improve the strength performance and elongation of the aluminum alloy profile, the preparation method is not only simple and convenient, but also easy to mass-produce.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal material preparation, in particular to an aluminum alloy profile with mixed crystal heterostructure characteristics and a preparation method. BACKGROUND

[0002] Aluminum alloy has good electrical conductivity and thermal conductivity, high strength-to-mass ratio, corrosion resistance and damage resistance, and is widely used in aerospace, rail transportation, automobiles, ships, pressure vessels, electronic appliances, furniture and many other fields. It is one of the most widely used metal materials in industry. Generally, metal materials have an inverted relationship between strength and plasticity, that is, increasing the strength of the material will result in a decrease in the plasticity of the material. Therefore, it is difficult to simultaneously improve the comprehensive mechanical properties of the alloy through conventional methods. In recent years, scholars at home and abroad have broken the previous "homogeneous" design concept of grain structure and designed and prepared some "heterogeneous" structure metal materials with different sizes or even cross-scale grains, breaking through the strength-plasticity limit of existing metal materials.

[0003] So far, there are still many bottlenecks in the batch production of aluminum alloy heterostructure materials. How to prepare heterostructure aluminum alloy profiles to fully utilize the advantages of heterostructure and improve the comprehensive mechanical properties of aluminum alloy profiles is the key to realizing their industrial application. The current methods for preparing heterostructure metal materials are mainly: (1) surface treatment (for example, surface mechanical grinding treatment (SMGT), surface mechanical attrition treatment (SMAT), shot peening treatment, etc.), which only forms a micro-zone heterostructure on the surface of the material; (2) powder metallurgy, which is a common method for manufacturing heterostructure materials; (3) additive manufacturing (AM), which can prepare heterostructure materials with controllable structure and customized properties; (4) mechanical thermal processing, such as asymmetric rolling (ASR), accumulative roll bonding (ARB), friction stir processing (FSP), etc. As can be seen, the existing methods for preparing heterostructure metal materials are not suitable for large-scale batch production, and are also not suitable for the preparation of alloy profiles.

[0004] The present application discloses an aluminum alloy profile with mixed crystal heterostructure characteristics and a preparation method, which can be used for batch production and large-scale industrial production. SUMMARY

[0005] The present application provides an aluminum alloy profile with mixed crystal heterostructure characteristics and a preparation method to solve the problem of batch production of aluminum alloy with heterostructure.

[0006] The technical solution of the present application to solve the above technical problems is as follows: a preparation method of an aluminum alloy profile with mixed crystal heterostructure characteristics, comprising:

[0007] melting, the melting of the pure Al, the Al intermediate alloy containing TiB2 and TiC particles, the Al intermediate alloy added for manufacturing different series of aluminum alloy profiles and the pure metal is carried out at a temperature of 800-850℃;

[0008] casting, the alloy after melting is cast at a temperature of 720℃-750℃ to form an ingot;

[0009] homogeneous heat treatment, the ingot is heated to 450℃-560℃ for 8-24 hours;

[0010] hot extrusion, the ingot after homogeneous heat treatment is extruded at a temperature of 400℃-450℃, according to an extrusion ratio of 20-60 and an extrusion speed of 0.5-10 m / min;

[0011] solid solution heat treatment, heat preservation is carried out at a temperature of 460℃-570℃ for 0.5-10 hours.

[0012] The beneficial effects of the present application are:

[0013] 1) The preparation method can prepare an alloy containing coarse and fine grain mixed grain structure by adding a small amount of TiB2 and TiC particles in the preparation of the aluminum alloy, and the proportion of coarse and fine grains can be adjusted and controlled, and the alloy with the mixed grain heterogeneous structure characteristics can simultaneously improve the strength performance and elongation of the aluminum alloy profile. The preparation method is not only simple and convenient, but also easy to mass-produce.

[0014] On the basis of the above technical scheme, the present application can also be improved as follows.

[0015] Further, the melting step of the alloy comprises:

[0016] S1, selecting the melting raw materials of the Al intermediate alloy containing TiB2 and TiC particles (10wt%-50wt%), the Al intermediate alloy added for manufacturing different series of aluminum alloy profiles and the pure Al (7wt%-21wt%), and putting the Al intermediate alloy containing TiB2 and TiC particles, the Al intermediate alloy added for manufacturing different series of aluminum alloy profiles and the pure Al into a melting furnace, wherein the composition of the Al intermediate alloy containing TiB2 and TiC particles is: TiB2 and TiC particles (3wt%-6wt%) and the balance of pure Al, and the proportion of TiB2 and TiC particles is 2:5-1:1 respectively;

[0017] S2, when the temperature in the melting furnace reaches above 780℃, inert gas protection is added;

[0018] S3, heating the temperature in the melting furnace to 800℃-850℃;

[0019] S4, after the alloy in the smelting furnace is completely melted, at least one pure metal with a melting point lower than Al is immersed into the alloy melt;

[0020] S5, the pure metal is stirred with the alloy melt using a stirrer;

[0021] S6, a melt purification process is performed in the smelting furnace to refine, degas and deslag.

[0022] Further, the aluminum intermediate alloy required for manufacturing different series of aluminum alloy profiles includes Al-20Si, Al-50Cu and Al-10Mn, and the metal element in S4 and S5 is Mg.

[0023] Further, the aluminum intermediate alloy required for manufacturing different series of aluminum alloy profiles includes Al-50Cu and Al-10Mn, and the metal element in S4 and S5 is Mg.

[0024] Further, the aluminum intermediate alloy required for manufacturing different series of aluminum alloy profiles includes Al-50Cu and Al-5Cr, and the metal element in S4 and S5 is Mg and Zn.

[0025] Further, the casting step of the alloy includes:

[0026] S1', first, the temperature of the alloy in the smelting furnace is lowered to 720-750°C;

[0027] S2', then, the smelted alloy is cast into round ingots using casting or semi-continuous casting.

[0028] Further, the uniform heat treatment includes heating the ingot in a heating furnace at 530-560°C for 8-16 hours, the hot extrusion includes extruding the ingot after the uniform heat treatment through an extruder at a temperature of 400-450°C, according to an extrusion ratio of 30-60 and an extrusion speed of 5-10 m / min, and the solid solution heat treatment includes a temperature of 550-570°C for 0.5-10 hours.

[0029] Further, the uniform heat treatment includes heating the ingot in a heating furnace at 480-530°C for 16-24 hours, the hot extrusion includes extruding the ingot after the uniform heat treatment through an extruder at a temperature of 400-450°C, according to an extrusion ratio of 20-50 and an extrusion speed of 0.8-4 m / min, and the solid solution heat treatment includes a temperature of 500-530°C for 0.5-10 hours.

[0030] Further, the uniform heat treatment comprises heating the ingot in a heating furnace at 450-470 DEG C for 18-24 hours, the hot extrusion comprises extruding the ingot after the uniform heat treatment by an extruder at 400-450 DEG C according to an extrusion ratio of 20-40 and an extrusion speed of 0.5-2 m / min, and the solid solution heat treatment comprises being at 460-475 DEG C for 0.5-10 hours.

[0031] An aluminum alloy profile with mixed crystal heterostructure characteristics, the aluminum alloy profile has mixed coarse and fine grains, wherein the coarse and fine grains in the grains are distributed in different proportions.

[0032] Further, different proportions of coarse and fine grains in the grains can be obtained by adjusting the time of the solid solution heat treatment. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 It is a schematic diagram of the overall structure of the present application;

[0034] Figure 2 It is an EBSD grain morphology diagram of the extruded hetero aluminum alloy profile of the present application modified by adding TiB2-TiC particles;

[0035] Figure 3 It is an EBSD grain morphology diagram of the extruded conventional aluminum alloy profile of the present application without adding TiB2-TiC particles modification;

[0036] Figure 4 It is a tensile mechanical property comparison diagram of the extruded alloy profile of the present application modified by adding TiB2-TiC particles and not modified by adding TiB2-TiC particles;

[0037] Figure 5 It is a tensile mechanical property diagram of the solid solution state conventional aluminum alloy profile of the present application without adding TiB2-TiC particles modification;

[0038] Figure 6 It is a tensile mechanical property diagram of the solid solution state hetero aluminum alloy profile of the present application modified by adding TiB2-TiC particles;

[0039] Figure 7 It is an EBSD grain morphology diagram of the solid solution state hetero aluminum alloy profile of the present application modified by adding TiB2-TiC particles, when the coarse and fine grain ratio is 1:3 at 560 DEG C for 1 hour;

[0040] Figure 8 It is an EBSD grain morphology diagram of the solid solution state hetero aluminum alloy profile of the present application modified by adding TiB2-TiC particles, when the coarse and fine grain ratio is 1:1 at 560 DEG C for 1.5 hours;

[0041] Figure 9 EBSD grain morphology map of the heterogeneous aluminum alloy profile modified by adding TiB2-TiC particles in the solid solution state after solid solution at 560℃ for 3 hours, the ratio of coarse grain to fine grain is 2:1;

[0042] Figure 10 EBSD grain morphology map of the heterogeneous aluminum alloy profile modified by adding TiB2-TiC particles in the solid solution state after solid solution at 560℃ for 10 hours, the ratio of coarse grain to fine grain is 3:1;

[0043] Figure 11 Schematic diagram of microstructure evolution of the alloy profile after extrusion and solid solution. DETAILED DESCRIPTION

[0044] The principles and characteristics of the present application are described below in conjunction with the accompanying drawings, and the examples are only used to explain the present application and are not intended to limit the scope of the present application.

[0045] Batch production of aluminum alloy heterogeneous structure materials still has many bottlenecks, how to prepare heterogeneous structure aluminum alloy profiles, and fully utilize the advantages of heterogeneous structure to improve the comprehensive mechanical properties of aluminum alloy profiles is the key to realize its industrial application. The current methods for preparing heterogeneous structure metal materials are mainly: (1) surface treatment (for example, surface mechanical grinding treatment (SMGT), surface mechanical attrition treatment (SMAT), shot peening treatment, etc.), which only forms a micro-zone heterogeneous structure on the surface of the material; (2 powder metallurgy, which is a general method for manufacturing heterogeneous flake structure and harmonic structure materials. (3) additive manufacturing (AM), this technology can prepare heterogeneous materials with controllable structure and customized properties; (4) mechanical thermal processing, such as asymmetric rolling (ASR), accumulative roll bonding (ARB), friction stir processing (FSP), etc. As can be seen, the existing reported methods for preparing heterogeneous structure metal materials are not suitable for large-scale batch production, and are also not suitable for the preparation of alloy profiles. To solve the above problems, the present application provides a kind of aluminum alloy profile with mixed crystal heterogeneous structure characteristics and a preparation method.

[0046] The present application provides the following preferred embodiments

[0047] Example 1

[0048] As Figures 1-10 shown, a preparation method of an aluminum alloy profile with mixed crystal heterogeneous structure characteristics, comprising:

[0049] S1, select aluminum intermediate alloy ingot containing TiB2 and TiC particles (10wt%-50wt%), Al-20Si (4wt%-7wt%), Al-50Cu (0wt%-1wt%), Al-10Mn (2wt%-8wt%), Mg ingot (1.3wt%-1.8wt%) and the balance of pure Al ingot as smelting raw materials, and put the aluminum intermediate alloy ingot containing TiB2 and TiC particles, Al-20Si, Al-50Cu, Al-10Mn and pure Al ingot into the smelting furnace (and the method for making TiB2 and TiC particle-containing aluminum intermediate alloy ingot added in this step can refer to the patent CN113373367A), wherein the composition of the aluminum intermediate alloy ingot containing TiB2 and TiC particles is: TiB2 and TiC particles (3wt%-6wt%) and the balance of pure Al, and the proportion of TiB2 and TiC particles is 2:5-1:1 (the configuration ratio can be but not limited to 2.2:1, 2.0:1 and 1.8:1, etc.), and the TiB2 particles are submicron, and the TiC particles are nanoscale;

[0050] (Note also that Al-50Cu and Al-10Mn respectively represent intermediate alloy ingot containing 50wt% Cu and the balance of pure Al and intermediate alloy ingot containing 10wt% Mn and the balance of pure Al, and similar formats appearing below are explained here, which is the conventional language of those skilled in the art, which will not be described here)

[0051] S2, when the temperature in the smelting furnace reaches above 780℃, inert gas argon is added to the smelting furnace for protection;

[0052] S3, heat the temperature in the smelting furnace to 800-850℃ (by high temperature of 800-850℃, the wettability between TiB2 and TiC particles and aluminum matrix can be increased);

[0053] S4, after the alloy in the smelting furnace is completely melted, the Mg ingot is immersed in the alloy melt;

[0054] S5, use a stirrer to stir the Mg ingot and the alloy melt uniformly;

[0055] S6, melt purification process, refining, degassing and deslagging in the smelting furnace, wherein the final composition of the remaining alloy after smelting is Mg: 1.2wt-1.8wt%, Si: 0.8wt-1.4wt%, Mn: 0.2wt-0.8wt%, Cu: 0wt-0.5wt%, and TiB2+TiC particles: 0.5wt-2.5wt%, and the rest is pure aluminum ingot;

[0056] S7, cooling the temperature of the alloy in the smelting furnace to 720-750°C (the smelting furnace can be closed, and the temperature in the furnace can be naturally cooled to 720-750°C);

[0057] S8, using casting or semi-continuous casting to cast the smelted alloy into round ingots;

[0058] S9, uniform heat treatment, placing the round ingot into a heating furnace and heating to 530-560°C for 8-16 hours;

[0059] S10, hot extrusion, extruding the uniformly heat-treated ingot through an extruder at a temperature of 400-450°C, an extrusion ratio of 30-60, and an extrusion speed of 5-10 m / min;

[0060] S11, solid solution heat treatment, heat treatment at a temperature of 550-570°C for 0.5-10 hours.

[0061] In this embodiment, the sub-micron TiB2 and nano-scale TiC particles added in S1 effectively refine the solidification structure of the AL-Mg-Si-Cu alloy, reducing the average grain size from 74.7 μm to 51.6 μm, inhibiting recrystallization during hot extrusion, preventing abnormal grain growth, and improving the stability of the Al-Mg-Si-Cu alloy structure during hot extrusion.

[0062] Therefore, in order to highlight the key role of sub-micron TiB2 and nano-scale TiC particles in the preparation of mixed crystal heterogeneous structure aluminum alloy profiles, the applicant provides two sets of comparative examples and four sets of experiments; (the comparative examples and experiments use the preparation of 6000 series aluminum alloy profiles as an example, i.e. the 6000 series Al-Mg-Si-Cu aluminum alloy prepared in Example 1, and in order to characterize the microstructure and performance characteristics of the aluminum alloy profile, an optical microscope (model: Lecia DFC, standard: JB / T 7946-2017) is used to observe the microstructure of the profile, a micro Vickers hardness tester (model: Zwick / Roell ZHVμ, standard: GB / T 4340) is used to measure the hardness value of the profile, and an electronic universal material testing machine (model: CMT 5105, standard: GB / T228.1) is used to obtain the tensile curve)

[0063] The parameters and steps used in the comparative examples and experiments are as follows:

[0064] Step 1, put the aluminum master alloy ingot (2200g) containing sub-micron TiB2and nano-scale TiC particles, Al-20Si (325g), Al-50Cu (30g), Al-10Mn (200g) master alloy ingot and pure Al ingot (2175g) into a melting furnace, wherein the composition of the aluminum master alloy ingot containing TiB2and TiC particles is: TiB2and TiC particles (11g) and pure Al (2090g), and the proportion of TiB2and TiC particles (110g) is 2:1 respectively;

[0065] Step 2, when the temperature in the melting furnace reaches 780℃, inert gas argon is added to the melting furnace for protection;

[0066] Step 3, heat the temperature in the melting furnace to 840℃;

[0067] Step 4, after the alloy in the melting furnace is completely melted, immerse the Mg ingot (70g) into the alloy melt;

[0068] Step 5, use a stirrer to stir the Mg ingot and the alloy melt uniformly;

[0069] Step 6, melt purification process, refining degassing and deslagging in the melting furnace, wherein the final composition of the remaining alloy after melting is Mg: 1.3wt%, Si: 1.3wt%, Mn: 0.4wt%, Cu: 0.3wt%, and TiB2+TiC particles: 2.2wt%, and the rest is pure Al ingot;

[0070] Step 7, reduce the temperature of the alloy in the melting furnace to 730℃;

[0071] Step 8, use the casting method to cast the melted alloy into a round ingot;

[0072] Step 9, uniform heat treatment, put the round ingot into a heating furnace and heat it to 550℃ for 10 hours;

[0073] Step 10, hot extrusion, extrude the uniformly heat treated ingot through an extruder at a temperature of 450℃, an extrusion ratio of 35 and an extrusion speed of 8m / min;

[0074] Step 11, solid solution heat treatment, heat treatment at a temperature of 560℃ for 0.5 hours to 10 hours.

[0075] Comparative Example 1

[0076] As Figure 4The figure shows the comparison of yield strength, tensile strength and elongation of the 6000 series Al-Mg-Si-Cu aluminum alloy profile prepared in Step 1 without TiB2 and TiC particles and the alloy with TiB2 and TiC particles after going through Step 2 to Step 10; (It should also be noted here that the alloy of the aluminum master alloy without TiB2 and TiC particles in the preparation step is the conventional alloy, and the alloy of the aluminum master alloy with TiB2 and TiC particles is the heterogeneous alloy. The conventional alloy and the heterogeneous alloy appearing below are based on the above description, and will not be repeated here)

[0077] Among them, the yield strength of the conventional alloy without TiB2 and TiC particles after going through the above Step 1 to Step 10 (extruded state conventional alloy profile) is 105(±5)MPa, the tensile strength is 225(±4)MPa, and the elongation is 30.7%;

[0078] And the yield strength of the heterogeneous alloy with TiB2 and TiC particles after going through the above Step 1 to Step 10 (extruded state heterogeneous alloy profile) is 148(±5)MPa, the tensile strength is 255(±4)MPa, and the elongation is 12.7(±0.5)%. Therefore, the yield strength and tensile strength of the extruded heterogeneous alloy profile prepared after adding TiB2 and TiC particles are increased by 41% and 13% respectively compared with the extruded heterogeneous alloy profile without TiB2 and TiC particles, and the elongation after breaking is maintained at a good 12.5%. (It should also be noted here that the extruded heterogeneous alloy profile is the 6000 series Al-Mg-Si-Cu aluminum alloy profile with heterogeneous structure prepared by the heterogeneous alloy with TiB2 and TiC particles after going through Step 1 to Step 10, the extruded conventional alloy profile is the conventional 6000 series Al-Mg-Si-Cu aluminum alloy profile prepared by the conventional alloy without TiB2 and TiC particles after going through Step 1 to Step 10, and the solid solution state heterogeneous alloy profile is the 6000 series Al-Mg-Si-Cu aluminum alloy profile with heterogeneous structure prepared by the heterogeneous alloy with TiB2 and TiC particles after going through Step 1 to Step 11, and the solid solution state conventional alloy profile is the conventional 6000 series Al-Mg-Si-Cu aluminum alloy profile prepared by the conventional alloy without TiB2 and TiC particles after going through Step 1 to Step 11)

[0079] Comparative Example 2

[0080] The parameters used in Step 1 to Step 10 in Comparative Example 1 are consistent with those used in Step 1 to Step 10 in Comparative Example 1, such as Figure 5The figure shows the line graphs of yield strength, tensile strength, and elongation of the conventional alloy profile without TiB2 and TiC particles after steps 2 to 10 in the preparation of 6000 series Al-Mg-Si-Cu aluminum alloy profiles, and after the solution heat treatment stage in step 11, where the holding temperature is set at 560℃ and the solution heat treatment time is 1h, 1.5h, 3h, and 10h respectively.

[0081] Among them, the yield strength of the conventional alloy after 1 hour of solution heating is 104 MPa, the tensile strength is 232 MPa, and the elongation is 25.2%.

[0082] The yield strength, tensile strength, and elongation of the conventional alloy after 1.5 hours of solution heating are 100 MPa, 230 MPa, and 27.2%, respectively.

[0083] The yield strength, tensile strength, and elongation of the conventional alloy after 3 hours of solution heating are 101 MPa, 232 MPa, and 22.2%, respectively.

[0084] The yield strength, tensile strength, and elongation of the conventional alloy after 10 hours of solution heating are 95 MPa, 226 MPa, and 23.3%, respectively.

[0085] like Figure 6 The figure shows the line graphs of yield strength, tensile strength and elongation of the hetero alloy with added TiB2 and TiC particles after steps 2 to 10 in the preparation of 6000 series Al-Mg-Si-Cu aluminum alloy profiles, and after the solution heat treatment in step 11, the holding temperature is set at 560℃ and the solution heat treatment time is 1h, 1.5h, 3h and 10h respectively.

[0086] The heteroalloy exhibits the following properties after 1 hour of solution heating: yield strength: 174 MPa, tensile strength: 293 MPa, and elongation: 13.5%.

[0087] Yield strength of the dissimilar alloy after 1.5 hours of solution heating: 180 MPa, tensile strength: 303 MPa, elongation: 15.0%;

[0088] Yield strength of the dissimilar alloy after 3 hours of solution heating: 227 MPa, tensile strength: 345 MPa, elongation: 12.0%;

[0089] Yield strength of the dissimilar alloy after 10 hours of solution heating: 163 MPa, tensile strength: 288 MPa, elongation: 15.2%;

[0090] Please refer to Figure 4 and Figure 6, after the heterogeneous alloy with TiB2 and TiC particles added respectively after step 1~step 10 and step 1~step 11, wherein the alloy profile after step 11 reaches a specific heterogeneous structure feature, that is, the ratio of coarse grains and fine grains in the grain is different, and when the ratio of coarse grains and fine grains is 2:1 after 3h solid solution heat treatment, the tensile strength and yield strength of the solid solution state heterogeneous alloy profile are increased by 35% and 53% respectively compared with the extruded state heterogeneous alloy profile, and the elongation is not lost, and the performance is close to the peak aging strength of the conventional alloy profile of the same composition;

[0091] In addition, please refer to Figure 5 and Figure 6 , after the heterogeneous alloy with TiB2 and TiC particles added respectively after step 1~step 11, compared with the conventional alloy without TiB2 and TiC particles added after step 1~step 11, the solid solution state heterogeneous alloy profile made after step 11 is set to 560℃, after 1h, 1.5h, 3h, 10h solid solution heat treatment, the yield strength and tensile strength are increased by 67% and 26%, 80% and 32%, 125% and 49%, 71% and 27% respectively, and the elongation is kept above 12% on average. Figure 5 In the formula, st represents the conventional alloy without TiB2 and TiC particles added, Figure 6 In the formula, C-F represents the heterogeneous alloy with TiB2 and TiC particles added, and the following numbers represent the ratio of coarse grains and fine grains after different lengths of solid solution heat treatment)

[0092] In order to verify the influence of the alloy profile organization reaching a specific heterogeneous structure feature, that is, the different ratio of coarse grains and fine grains in the grain on the yield strength, tensile strength and elongation of the alloy profile, the applicant provides four groups of experiments;

[0093] Experiment 1

[0094] Please refer to Figure 6 and Figure 7 , the same preparation steps and parameters as in comparative example 2 after adding TiB2 and TiC particles are used in this experiment, the difference is that the holding temperature of step 11 in this experiment is 560℃, and the solid solution heat treatment time is 1h, the ratio of coarse grains and fine grains in the alloy profile is 1:3 after EBSD grain morphology analysis, and the yield strength is 174MPa, the tensile strength is 293MPa, and the elongation is 13.5%;

[0095] Experiment 2

[0096] Please refer to Figure 6 and Figure 8In this experiment, the same preparation steps and parameters as those in Comparative Example 2 were used after adding TiB2 and TiC particles. The difference was that the holding temperature of S11 was set at 560℃ and the solution heat treatment time was 1.5h. According to the EBSD grain morphology analysis, the ratio of coarse grains to fine grains in the alloy profile was 1:1, and the yield strength was 180MPa, the tensile strength was 303MPa, and the elongation was 15.0%.

[0097] Experiment 3

[0098] Please refer to Figure 6 and Figure 9 In this experiment, the same preparation steps and parameters as those in Comparative Example 2 were used after adding TiB2 and TiC particles. The difference was that in this experiment, the holding temperature of S11 was set at 560℃ and the solution heat treatment time was 3h. According to the EBSD grain morphology analysis, the ratio of coarse grains to fine grains in the alloy profile was 2:1, and the yield strength was 227MPa, the tensile strength was 345MPa, and the elongation was 12.0%.

[0099] Experiment 4

[0100] Please refer to Figure 6 and Figure 10 In this experiment, the same preparation steps and parameters as those in Comparative Example 2 were used after adding TiB2 and TiC particles. The difference was that in this experiment, the holding temperature of S11 was set at 560℃ and the solution heat treatment time was 10h. According to the EBSD grain morphology analysis, the ratio of coarse grains to fine grains in the alloy profile was 3:1, and the yield strength was 163MPa, the tensile strength was 288MPa, and the elongation was 15.2%.

[0101] Please refer to Figure 11 ( Figure 11The microstructure evolution of the A row (a conventional alloy without adding TiB2 and TiC particles) under the same preparation steps and parameters as the experiment is shown in the figure, and the microstructure evolution of the B row (a heterogeneous alloy with TiB2 and TiC particles) under the same preparation steps and parameters as the experiment is shown in the figure. Therefore, through the above comparative experiment and analysis: adding a small amount of TiB2 and TiC particles during the preparation of the aluminum alloy makes the TiB2 and TiC particles in the matrix in a discontinuous layer distribution. In addition to the particles in the matrix, most of the particles are gathered along the extrusion direction. This particle distribution leads to the formation of particle-rich and particle-poor regions. These non-uniformly distributed particles are the premise of heterogeneous grain crystallization of the aluminum alloy profile in subsequent heat treatment. The particles cause the alloy to flow unevenly during hot extrusion, so that most of the as-cast grains are broken into fine equiaxed grains, and the remaining grains are deformed into fine elongated grains. The particles play a Zener pinning effect, hinder the sliding and migration of the grain boundary, inhibit recrystallization, and effectively prevent grain growth. After solid solution heat treatment, the particles in the rich region have a strong pinning effect, and the driving force of the solid solution heat treatment is not enough to activate extensive recrystallization. Most of the broken fine extrusion grains are still preserved in the particle-rich region and its surroundings. The grains in the sparse region undergo more severe deformation during extrusion and have higher deformation energy storage. The lack of particles results in a weaker pinning effect, and the grains are more likely to recrystallize.

[0102] On the other hand, grains that have undergone severe plastic deformation have a higher tendency to abnormally grow at high temperatures. During the solid solution heat treatment process, the grains in the particle-poor region undergo more severe extrusion deformation and abnormally grow, forming a heterogeneous structure of the alloy profile.

[0103] Combining the comparative experiment and the experiment, it is found that as the solid solution time increases, the content of coarse grains in the heterogeneous structure increases, and the content of fine grains decreases. By adjusting the solid solution heat treatment time, a heterogeneous structure with different coarse / fine grain ratios can be obtained to manufacture aluminum alloys with different properties and also have a heterogeneous structure. Thus, the application field and use are more, and it has strong practicality. Especially after the heterogeneous alloy with TiB2 and TiC particles undergoes steps 1-11, the solid solution state heterogeneous alloy profile is set to a holding temperature of 560°C in step 11, and the solid solution heat treatment time is 3h. Through EBSD grain morphology analysis, the ratio of coarse grains to fine grains in the alloy profile is 2:1, the yield strength is increased by 125%, the tensile strength is increased by 49%, and the elongation is maintained. Good, it has better comprehensive mechanical properties.

[0104] Example 2

[0105] Compared with Example 1, the prepared is a 2000 series Al-Cu-Mg aluminum alloy profile, and the specific preparation steps include:

[0106] S1', select an aluminum intermediate alloy ingot (10wt%-50wt%) containing TiB2 and TiC particles, Al-50Cu (7.6wt%-9.8wt%), Al-10Mn (3wt%-9wt%), Mg ingot (1.3wt%-1.8wt%) and the balance of pure Al ingot as the smelting raw material, and put the aluminum intermediate alloy ingot containing TiB2 and TiC particles, Al-50Cu, Al-10Mn and pure Al ingot into the smelting furnace, wherein the aluminum intermediate alloy ingot containing TiB2 and TiC particles has the following composition: TiB2 and TiC particles (3wt%-6wt%) and the balance of pure Al, and the proportion of TiB2 and TiC particles is 2:5-1:1 (the configuration ratio can be but not limited to 2.2:1, 2.0:1 and 1.8:1, etc.);

[0107] S2', when the temperature in the smelting furnace reaches above 780℃, inert gas argon is added for protection;

[0108] S3', heat the temperature in the smelting furnace to 800℃-850℃;

[0109] S4', after the alloy in the smelting furnace is completely melted, the Mg ingot is added to the melt;

[0110] S5', use a stirrer to stir the Mg ingot and the alloy uniformly;

[0111] S6', melt purification process, refining, degassing and deslagging in the smelting furnace, wherein the remaining alloy composition after smelting is Mg: 1.2wt-1.8wt%, Mn: 0.3wt-0.9wt%, Cu: 3.8wt-4.9wt%, and TiB2+TiC particles: 0.5wt-2.5wt%, and the rest is pure Al ingot;

[0112] S7', reduce the temperature of the alloy in the smelting furnace to 720℃-750℃ (the smelting furnace can be closed, and the temperature in the furnace can be naturally cooled to 720℃-750℃);

[0113] S8', use casting or semi-continuous casting to cast the smelted alloy into round ingots;

[0114] S9', uniform heat treatment, put the round ingot into a heating furnace and heat it to 480℃-530℃ for 16-24 hours;

[0115] S10', hot extrusion, the cast ingot after uniform heat treatment is extruded by an extruder at a temperature of 400-450°C, according to an extrusion ratio of 20-50 and an extrusion speed of 0.8-4 m / min;

[0116] S11', solution heat treatment, heat preservation at a temperature of 500-530°C for 0.5-10 hours.

[0117] Example 3

[0118] In this example 3, compared with example 1, the prepared is a 7000 series Al-Zn-Mg-Cu aluminum alloy profile, and the specific preparation steps include:

[0119] S1", the smelting raw materials including an aluminum intermediate alloy ingot (10wt%-50wt%) containing TiB2 and TiC particles, Al-50Cu (0wt%-4wt%), Al-5Cr (1wt%-5wt%), Mg ingot (2wt%-3wt%), Zn ingot (5wt%-7wt%) and the rest is pure Al ingot are put into a smelting furnace, wherein the aluminum intermediate alloy ingot containing TiB2 and TiC particles contains TiB2 and TiC particles (3wt%-6wt%) and the rest is pure Al, and the proportion of TiB2 and TiC particles is 2:5-1:1 (the configuration ratio can be but is not limited to 2.2:1, 2.0:1 and 1.8:1, etc.);

[0120] S2", when the temperature in the smelting furnace reaches above 780°C, inert gas argon is added for protection;

[0121] S3", the temperature in the smelting furnace is heated to 800-850°C;

[0122] S4", after the alloy in the smelting furnace is completely melted, the Mg ingot and the Zn ingot are immersed in the melt;

[0123] S5", the Mg ingot and the Zn ingot are stirred uniformly with the alloy by using a stirrer;

[0124] S6", melt purification process, refining, degassing and deslagging are carried out in the smelting furnace, wherein the final composition of the remaining alloy after smelting is Mg: 2.0wt-3.0wt%, Zn: 5.0wt-7.0wt%, Cu: 0wt-2wt%, Cr: 0.05wt-0.25wt%, and TiB2+TiC particles: 0.5wt-2.5wt%, and the rest is pure Al ingot;

[0125] S7", the temperature of the alloy in the smelting furnace is cooled to 720-750°C (the smelting furnace can be closed, and the temperature in the furnace is naturally cooled to 720-750°C);

[0126] S8", casting the smelted alloy into round ingot by using casting or semi-continuous casting;

[0127] S9", uniform heat treatment, putting the round ingot into a heating furnace to heat at 450-470°C for 18-24 hours;

[0128] S10", hot extrusion, extruding the round ingot after uniform heat treatment by an extruder at 400-450°C, according to extrusion ratio of 20-40 and extrusion speed of 0.5-2 m / min;

[0129] S11", solid solution heat treatment, heat preservation at 460-475°C for 0.5-10 hours.

[0130] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for producing an aluminum alloy profile having a mixed crystal heterostructure feature, characterized by, The method comprises the following steps: melting, melting the pure Al, the Al intermediate alloy containing TiB2 and TiC particles, and the Al intermediate alloy required for manufacturing different series of aluminum alloy profiles at a temperature of 800-850℃; casting, casting the alloy after melting at a temperature of 720℃-750℃ to form an ingot; homogeneous heat treatment, heating the ingot to 450℃-560℃ for 8-24 hours; hot extrusion, extruding the ingot after homogeneous heat treatment at a temperature of 400℃-450℃ according to an extrusion ratio of 20-60 and an extrusion speed of 0.5-10 m / min; solid solution heat treatment, heat preservation at a temperature of 460℃-570℃ for 0.5-10 hours; The melting step of the alloy comprises the following steps: S1, selecting 10wt%-50wt% of the Al intermediate alloy containing TiB2 and TiC particles, 7wt%-21wt% of the Al intermediate alloy required for manufacturing different series of aluminum alloy profiles, and the rest of pure Al as the melting raw materials, and putting the Al intermediate alloy containing TiB2 and TiC particles, the Al intermediate alloy required for manufacturing different series of aluminum alloy profiles, and pure Al into a melting furnace, wherein the Al intermediate alloy containing TiB2 and TiC particles comprises 3wt%-6wt% of TiB2 and TiC particles and the rest of pure Al, and the proportion of TiB2 and TiC particles is 2:5-1:1, and the TiB2 particles are submicron, and the TiC particles are nanometer; S2, adding inert gas protection when the temperature in the melting furnace reaches above 780℃; S3, heating the temperature in the melting furnace to 800℃-850℃; S4, after the alloy in the melting furnace is completely melted, immersing at least one pure metal with a melting point lower than Al into the alloy melt; S5, stirring the pure metal and the alloy melt uniformly by using a stirrer; S6, melt purification process, refining, degassing, and deslagging in the melting furnace; After the aluminum alloy profile is prepared by the above method, the aluminum alloy profile has mixed coarse and fine grains, wherein when the heat preservation temperature of the solid solution heat treatment is 560℃, and the solid solution heat treatment time is 1 hour, 1.5 hours, 3 hours, and 10 hours, the proportion of coarse and fine grains in the aluminum alloy profile is 1:3, 1:1, 2:1, and 3:1, respectively.

2. The method of producing an aluminum alloy profile having a mixed crystal heterostructure characteristic according to claim 1, characterized by, The Al intermediate alloy required for manufacturing different series of aluminum alloy profiles comprises Al-20Si, Al-50Cu, and Al-10Mn, and the pure metal in S4 and S5 is Mg.

3. The method for preparing an aluminum alloy profile with mixed-crystal heterostructure characteristics according to claim 1, characterized in that, The Al intermediate alloy required for manufacturing different series of aluminum alloy profiles comprises Al-50Cu and Al-10Mn, and the pure metal in S4 and S5 is Mg.

4. The method for preparing an aluminum alloy profile with mixed-crystal heterostructure characteristics according to claim 1, characterized in that, The Al intermediate alloy required for manufacturing different series of aluminum alloy profiles comprises Al-50Cu and Al-5Cr, and the pure metal in S4 and S5 is Mg and Zn.

5. The method of producing an aluminum alloy profile having a mixed crystal heterostructure characteristic according to claim 1, characterized by, The casting step of the alloy comprises the following steps: S1', first reducing the temperature of the alloy in the melting furnace to 720℃-750℃; S2', reusing casting or semi-continuous casting to cast the smelted alloy into round ingots.

6. The method of producing an aluminum alloy profile having a mixed crystal heterostructure characteristic according to claim 2, characterized by, The homogenizing heat treatment includes heating the ingot in a heating furnace at 530-560°C for 8-16 hours, the hot extrusion includes extruding the ingot after the homogenizing heat treatment by an extruder at 400-450°C according to an extrusion ratio of 30-60 and an extrusion speed of 5-10 m / min, and the solid solution heat treatment includes heating at 550-570°C for 0.5-10 hours.

7. The method of producing an aluminum alloy profile having a mixed crystal heterostructure characteristic according to claim 3, characterized by, The homogenizing heat treatment includes heating the ingot in a heating furnace at 480-530°C for 16-24 hours, the hot extrusion includes extruding the ingot after the homogenizing heat treatment by an extruder at 400-450°C according to an extrusion ratio of 20-50 and an extrusion speed of 0.8-4 m / min, and the solid solution heat treatment includes heating at 500-530°C for 0.5-10 hours.

8. The method of producing an aluminum alloy profile having a mixed crystal heterostructure characteristic according to claim 4, characterized by, The homogenizing heat treatment includes heating the ingot in a heating furnace at 450-470°C for 18-24 hours, the hot extrusion includes extruding the ingot after the homogenizing heat treatment by an extruder at 400-450°C according to an extrusion ratio of 20-40 and an extrusion speed of 0.5-2 m / min, and the solid solution heat treatment includes heating at 460-475°C for 0.5-10 hours.

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