CN120099362A

CN120099362A - A high-strength aluminum alloy for vehicle body and preparation method thereof

Info

Publication number: CN120099362A
Application number: CN202510577968.9A
Authority: CN
Inventors: 俞慧冈; 干志强
Original assignee: Shanghai Xinyi Ruijie Non Ferrous Alloy Co ltd
Current assignee: Shanghai Xinyi Ruijie Non Ferrous Alloy Co ltd
Priority date: 2025-05-07
Filing date: 2025-05-07
Publication date: 2025-06-06
Anticipated expiration: 2045-05-07
Also published as: CN120099362B

Abstract

本申请涉及汽车合金技术领域，具体公开了一种高强度车身用铝合金及其制备方法。一种高强度车身用铝合金，其由包含以下质量百分比的原料制成：镁0.5‑1.5%；硅1‑2%；铜0.4‑1%；锡0.1‑0.5%；锰0.01‑0.05%；铁0.05‑0.1%；硼0.1‑0.2%；稀土元素混料0.3‑1.5%；余量为铝；所述稀土元素混料由铌、钪和钴组成，且铌、钪和钴的重量比为1:（3.4‑4.4）:（12‑15）。其制备方法为：在惰性气体保护下，将铝进行熔化，然后按比例加入镁、硅、铜、锡、锰、铁、硼、稀土元素混料进行混合熔炼，得到熔炼液；在熔炼液中加入使用精炼剂进行精炼处理，经除渣和脱气处理后，浇注制得合金半成品；将合金半成品进行固溶处理，再经时效处理得到。本申请的高强度车身用铝合金具有较高的强度，且兼顾优异的延展性，整体品质较佳。The present application relates to the technical field of automobile alloys, and specifically discloses a high-strength aluminum alloy for automobile bodies and a preparation method thereof. A high-strength aluminum alloy for automobile bodies is made of raw materials containing the following mass percentages: magnesium 0.5-1.5%; silicon 1-2%; copper 0.4-1%; tin 0.1-0.5%; manganese 0.01-0.05%; iron 0.05-0.1%; boron 0.1-0.2%; rare earth element mixture 0.3-1.5%; the balance is aluminum; the rare earth element mixture is composed of niobium, scandium and cobalt, and the weight ratio of niobium, scandium and cobalt is 1:(3.4-4.4):(12-15). The preparation method is as follows: under the protection of inert gas, aluminum is melted, and then magnesium, silicon, copper, tin, manganese, iron, boron, and rare earth elements are added in proportion for mixed smelting to obtain a molten liquid; a refining agent is added to the molten liquid for refining treatment, and after slag removal and degassing treatment, an alloy semi-finished product is cast; the alloy semi-finished product is subjected to solid solution treatment and then aging treatment. The high-strength aluminum alloy for car body of the present application has high strength, excellent ductility, and good overall quality.

Description

High-strength aluminum alloy for automobile body and preparation method thereof

Technical Field

The application relates to the technical field of automobile alloys, in particular to an aluminum alloy for a high-strength automobile body and a preparation method thereof.

Background

The aluminum alloy is an alloy which is processed by taking aluminum as a main component and adding other metal elements through a specific process, belongs to light metal materials ‌ and plays a vital role in the industrial field. Meanwhile, due to the characteristics of light weight, high strength, good formability and the like of the aluminum alloy, the aluminum alloy is increasingly widely applied to automobile body structures, is mainly applied to parts such as automobile body frames, automobile doors, engine covers and trunk lids, and improves fuel economy and collision safety ‌.

At present, in the automobile industry, al-Mg-Si series aluminum alloys are widely used for a vehicle body frame structure due to low density, good formability and recovery value, however, with the continuous improvement of the safety of vehicles in the automobile industry, the traditional Al-Mg-Si alloys are difficult to meet the requirements of new generation high-performance vehicle body design due to lower yield strength and tensile strength. In recent years, the strength of aluminum alloys has been improved by adding trace alloying elements such as Cu and Sn, or by heat treatment or the like, but the above-mentioned methods can improve the strength to some extent, but often at the cost of sacrificing the ductility, resulting in limited practical application of aluminum alloys to automobile bodies.

In view of the above related art, the high-strength aluminum alloy body can absorb energy better, so as to resist collision and impact effectively and protect passengers, the high-ductility aluminum alloy body can resist deformation and fracture better, keep the integrity of the body structure, and limit the application of the aluminum alloy in manufacturing of complex shapes when the ductility of the aluminum alloy is poor, so that how to maintain and even improve the ductility of the aluminum alloy while improving the strength of the aluminum alloy has become one of the difficulties to be broken through in the industry. There is a need to propose a solution to the above technical problems.

Disclosure of Invention

The application provides an aluminum alloy for a high-strength vehicle body and a preparation method thereof, which aim to improve the strength of the aluminum alloy and simultaneously realize excellent ductility of the aluminum alloy.

In a first aspect, the application provides an aluminum alloy for a high-strength vehicle body, which adopts the following technical scheme:

the high-strength aluminum alloy for the vehicle body is prepared from the following raw materials in percentage by mass:

0.5 to 1.5 percent of magnesium;

1-2% of silicon;

copper 0.4-1%;

0.1-0.5% of tin;

manganese 0.01-0.05%;

Iron 0.05-0.1%;

Boron 0.1-0.2%;

0.3 to 1.5 percent of rare earth element mixture;

the balance of aluminum;

The rare earth element mixture consists of niobium, scandium and cobalt, wherein the weight ratio of the niobium to the scandium to the cobalt is 1 (3.4-4.4) to 12-15.

By adopting the technical scheme, magnesium can promote grain refinement and deformation treatment hardening of the aluminum alloy, so that the strength of the aluminum alloy can be improved, silicon and aluminum form solid solution, the crystal structure of the aluminum is enhanced, and therefore the mechanical property ‌ of the alloy is improved, copper can strengthen the grain boundary strength and solid solution strength of the aluminum alloy, and further the strength and hardness of the aluminum alloy can be remarkably improved, a compound formed by tin and aluminum plays a role in dispersion strengthening in the alloy, and further the strength and hardness of the aluminum alloy are improved, and a relatively stable phase structure of the aluminum alloy can be formed by adopting the combination of magnesium, silicon, copper, tin and aluminum, so that the aluminum alloy is excellent in strength, corrosion resistance and processability and can be easily accepted and fused with other different elements.

The alloy has the advantages that the corrosion resistance of the aluminum alloy can be improved due to the proper manganese content, the brittleness of the aluminum alloy can be increased due to the excessive manganese content, the hardness of the aluminum alloy is reduced by ‌, the high-temperature fluidity of the alloy can be improved due to the proper iron content in the aluminum alloy, the shrinkage rate of the aluminum alloy is reduced, the processability is improved, the plasticity of the aluminum alloy is reduced due to the excessive iron content, and the strength and the hardness are reduced, so that the manganese and the iron in the dosage range can bring the excellent effects, and meanwhile, the adverse effects are not easy to generate, and the integral stability of the aluminum alloy is further ensured.

The rare earth element mixture is composed of niobium, scandium and cobalt, wherein the niobium and the cobalt can accelerate the dissolution and the diffusion of rare elements in the aluminum alloy, the scandium regulates the size and the distribution of crystal grains by controlling the growth speed of crystal lattices, and the cooperation of the niobium, the scandium and the cobalt can bring about the comprehensive improvement of the hardness and the ductility of the aluminum alloy. The boron forms fine crystal nucleus with aluminum in aluminum alloy, and the crystal nucleus exists stably in aluminum liquid to become the starting point of grain growth, so that the grains in the aluminum liquid are obviously refined, and the strength, plasticity and toughness of the aluminum alloy can be improved. Meanwhile, when the rare earth element mixture consisting of niobium, scandium and cobalt is used, the rare earth element mixture can be combined with boron, and then the effect of promoting crystal nucleus formation and refining grains is brought, so that the microstructure of the alloy is improved, and fine particles which are combined and grown are uniformly distributed in the grain boundary and can be subjected to coordinated deformation through grain boundary sliding, so that the strength of the excellent aluminum alloy is improved, and the ductility of the aluminum alloy is remarkably improved.

Preferably, the weight ratio of niobium, scandium and cobalt is 1:4:14.

By adopting the technical scheme, when the rare earth element mixture is formed by niobium, scandium and cobalt according to the weight ratio, the self-excellent action effect can be stably exerted, the excellent synergistic effect can be exerted in the aluminum alloy by matching with boron, stable hard phase particles are formed, the aluminum alloy is subjected to dispersion strengthening, the strength is obviously improved, the better grain boundary sliding coordination deformation effect can be brought, and the better ductility is further shown.

Preferably, the weight ratio of the boron to the rare earth element mixture is 1:5.

Through adopting above-mentioned technical scheme, when the boron of above-mentioned weight ratio and rare earth element compounding are collocated and are used, its cooperation system that forms in aluminum alloy is comparatively even, and brings corresponding effect preferred, can make aluminum alloy compromise excellent ductility when improving aluminum alloy intensity, and whole performance is preferred.

Preferably, the mass percentages of the magnesium, the silicon, the copper and the tin are as follows:

0.8-1.2% of magnesium;

1.2 to 1.8 percent of silicon;

Copper 0.6-0.8%;

0.2 to 0.4 percent of tin.

By adopting the technical scheme, when the magnesium, the silicon, the copper and the tin with the mass percentages are mixed, the formation of a precipitated phase of the aluminum alloy after solution treatment is more balanced, the subsequent aging strengthening is facilitated, the boron and the rare earth element mixed materials are more easily matched in an alloy system, the better corresponding effect is exerted, and the aluminum alloy with better quality for the high-strength automobile body is obtained.

In a second aspect, the application provides a method for preparing an aluminum alloy for a high-strength vehicle body, which adopts the following technical scheme:

A preparation method of high-strength aluminum alloy for a vehicle body comprises the following steps:

(1) Preparing raw materials containing magnesium, silicon, copper, tin, manganese, iron, boron, rare earth element mixture and aluminum according to a proportion;

(2) Under the protection of inert gas, melting the aluminum in the step (1), and then adding mixed materials of magnesium, silicon, copper, tin, manganese, iron, boron and rare earth elements in proportion for mixed smelting to obtain smelting liquid;

(3) Adding a refining agent into the smelting liquid obtained in the step (2) for refining treatment, and pouring after deslagging and degassing treatment to obtain an alloy semi-finished product;

(4) And (3) carrying out solution treatment on the alloy semi-finished product obtained in the step (3), then carrying out aging treatment, and cooling to obtain the high-strength aluminum alloy for the vehicle body.

By adopting the technical scheme, the preparation steps are fewer, the process is simple, and the large-scale industrial production is convenient. The aluminum alloy for the high-strength automobile body can ensure that the raw materials can be fully matched to exert excellent corresponding action effects, and can ensure that the aluminum alloy for the high-strength automobile body with excellent and stable quality can be obtained through refining treatment, solid solution treatment and aging treatment after the raw materials are mixed and smelted.

Preferably, in the step (2), the smelting temperature is 700-800 ℃ and the smelting time is 2-3h.

By adopting the technical scheme, the smelting temperature and the smelting time can ensure the full mixing of all the component raw materials, so that the alloy elements are not easy to burn, and the aluminum alloy with excellent and stable quality is obtained finally.

Preferably, in the step (3), the refining temperature is 820-860 ℃ and the refining time is 30-40min.

By adopting the technical scheme, the refining is to add the refining agent into the smelting liquid to carry out degassing and deslagging treatment, and the refining temperature and the refining time are favorable for dissolving alloy elements and exhausting gas and impurities, so that the finally obtained aluminum alloy has excellent quality.

Preferably, in the step (3), the amount of the refining agent is 0.1-0.2% of the mass of the smelting liquid, and the refining agent is any one or a combination ‌ of sodium chloride, potassium chloride, ‌ sodium fluoride and calcium fluoride ‌.

By adopting the technical scheme, the refining agent composed of the raw materials has stronger impurity removal and degassing capabilities, not only can improve the uniformity of the aluminum alloy, but also has the effects of modifying and refining the aluminum alloy structure, improves the melt properties of the aluminum alloy such as fluidity, wettability, solidification shrinkage and the like, brings about the improvement of the casting performance and the forming performance ‌ of the aluminum alloy, and is favorable for ensuring the high-strength aluminum alloy for the vehicle body with excellent and stable quality.

Preferably, in the step (4), the temperature of the solution treatment is 520-540 ℃, and the heat preservation time is 3-4h.

By adopting the technical scheme, the solid solution treatment can optimize the structure of the aluminum alloy, reduce the structure non-uniformity and further improve the overall performance of the aluminum alloy, and the matching of the solid solution treatment temperature and the solid solution time can bring better corresponding action effect, so that the aluminum alloy with excellent and stable quality for the high-strength automobile body is finally obtained.

Preferably, in the step (4), the temperature of the aging treatment is 160-180 ℃ and the heat preservation time is 3-4h.

By adopting the technical scheme, the strength and the hardness of the aluminum alloy are obviously improved through precipitation strengthening phases in the aging treatment, the processing performance is obviously improved, a layer of compact oxide film is formed on the surface of the aluminum material, the corrosion resistance of the aluminum material can be effectively improved, the matching of the aging treatment temperature and the aging treatment time can bring better corresponding action effects, and finally the high-strength aluminum alloy for the vehicle body with excellent and stable quality is obtained.

In summary, the application has the following beneficial effects:

according to the application, the rare earth element mixture composed of niobium, scandium and cobalt is matched with boron for synergistic cooperation, so that the microstructure of the alloy can be improved, and the effect of coordinating deformation of grain boundary sliding can be brought by uniformly distributing the grown fine particles in the grain boundary, thereby improving the strength of the aluminum alloy and simultaneously achieving excellent ductility of the aluminum alloy.

Detailed Description

The present application will be described in further detail with reference to examples.

Example 1

The high-strength aluminum alloy for the vehicle body is prepared from the following raw materials in percentage by weight as shown in table 1:

In the operation, the rare earth element mixture consists of niobium, scandium and cobalt, and the weight ratio of the niobium to the scandium to the cobalt is 1:4:14. In the step (2), the smelting temperature is 750 ℃ and the smelting time is 2.5h. In the step (3), the refining temperature is 840 ℃, the refining time is 35min, the consumption of the refining agent is 0.15% of the mass of the smelting liquid, and the refining agent consists of sodium chloride, potassium chloride and calcium fluoride ‌ according to the weight ratio of 11:7:8. In the step (4), the temperature of the solution treatment is 530 ℃, the heat preservation time is 3.5h, the temperature of the aging treatment is 170 ℃, and the heat preservation time is 3.5h.

Examples 2 to 3

An aluminum alloy for a high-strength vehicle body is different from example 1 in that the respective raw materials and their respective weights are shown in table 1.

TABLE 1 examples 1-3 raw materials and corresponding mass percentages (%)

Raw materials	Example 1	Example 2	Example 3
				Magnesium (Mg)	1	0.5	1.5
Silicon (Si)	1.5	1	2
				Copper (Cu)	0.7	0.4	1
Tin (Sn)	0.3	0.1	0.5
				Manganese (Mn)	0.03	0.01	0.05
Iron (Fe)	0.075	0.05	0.1
				Boron (B)	0.15	0.1	0.2
Rare earth element mixture	0.9	0.3	1.5
				Aluminum (Al)	95.345	97.54	93.15

Example 4

The high-strength aluminum alloy for vehicle bodies is different from example 1 in that the rare earth element mixture is composed of niobium, scandium and cobalt, and the weight ratio of niobium, scandium and cobalt is 1:3.9:13.5.

Example 5

An aluminum alloy for a high-strength vehicle body is different from example 1 in that the rare earth element mixture is composed of niobium, scandium and cobalt, and the weight ratio of niobium, scandium and cobalt is 1:3.4:12.

Example 6

The high-strength aluminum alloy for vehicle bodies is different from example 1 in that the rare earth element mixture is composed of niobium, scandium and cobalt, and the weight ratio of niobium, scandium and cobalt is 1:4.4:15.

Example 7

The aluminum alloy for the high-strength automobile body is different from the aluminum alloy in the embodiment 1 in that the total mixing amount of boron and rare earth elements is unchanged, and the weight ratio of the boron to the rare earth elements is adjusted to be 1:5.

Examples 8 to 11

An aluminum alloy for a high-strength vehicle body is different from example 1 in that the respective raw materials and their respective weights are shown in table 2.

TABLE 2 examples 8-11 raw materials and corresponding mass percentages (%)

Raw materials	Example 8	Example 9	Example 10	Example 11
					Magnesium (Mg)	0.8	1.2	0.7	1.3
Silicon (Si)	1.2	1.8	1.1	1.9
					Copper (Cu)	0.6	0.8	0.5	0.9
Tin (Sn)	0.2	0.4	0.1	0.5
					Manganese (Mn)	0.03	0.03	0.03	0.03
Iron (Fe)	0.075	0.075	0.075	0.075
					Boron (B)	0.15	0.15	0.15	0.15
Rare earth element mixture	0.9	0.9	0.9	0.9
					Aluminum (Al)	96.045	94.645	96.445	94.245

Example 12

An aluminum alloy for a high-strength vehicle body is different from example 1 in that in step (2), the melting temperature is 700 ℃ and the melting time is 3 hours.

Example 13

An aluminum alloy for a high-strength vehicle body is different from example 1 in that in step (2), the melting temperature is 800 ℃ and the melting time is 2 hours.

Example 14

An aluminum alloy for a high-strength vehicle body is different from that of example 1 in that in step (3), the refining temperature is 820 ℃ and the refining time is 40min.

Example 15

An aluminum alloy for a high-strength vehicle body is different from that of example 1 in that in step (3), the refining temperature is 860 ℃ and the refining time is 30min.

Example 16

An aluminum alloy for a high-strength vehicle body, which is different from example 1 in that in step (3), the amount of a refining agent used is 0.2% by mass of a molten metal.

Example 17

An aluminum alloy for a high-strength vehicle body, which is different from example 1 in that in step (3), the amount of a refining agent used is 0.1% by mass of a molten metal.

Example 18

An aluminum alloy for a high-strength vehicle body is different from that of example 1 in that in step (4), the temperature of the solution treatment is 520 ℃ and the holding time is 4 hours.

Example 19

An aluminum alloy for a high-strength vehicle body is different from that of example 1 in that in step (4), the temperature of the solution treatment is 540 ℃ and the holding time is 3 hours.

Example 20

An aluminum alloy for a high-strength vehicle body is different from that of example 1 in that in step (4), the aging treatment temperature is 160 ℃ and the holding time is 4 hours.

Example 21

An aluminum alloy for a high-strength vehicle body is different from that of example 1 in that in step (4), the aging treatment temperature is 180 ℃ and the holding time is 3 hours.

Comparative example 1

An aluminum alloy for a high-strength vehicle body is different from that of example 1 in that the mass of boron in the raw material is replaced with aluminum.

Comparative example 2

An aluminum alloy for a high-strength vehicle body is different from that of example 1 in that the quality of the rare earth element mixture in the raw material is replaced with aluminum.

Comparative example 3

An aluminum alloy for a high-strength vehicle body is different from that of example 1 in that the quality of boron and rare earth element mixed materials in the raw materials is replaced by aluminum.

Comparative example 4

An aluminum alloy for a high-strength vehicle body is different from example 1 in that niobium and cobalt are not used in the rare earth element mixture.

Comparative example 5

An aluminum alloy for a high-strength vehicle body is different from example 1 in that scandium and cobalt are not used in the rare earth element mixture.

Comparative example 6

An aluminum alloy for a high-strength vehicle body is different from that of example 1 in that niobium and scandium are not used in the rare earth element mixture.

Comparative example 7

An aluminum alloy for a high-strength vehicle body is different from that of example 1 in that niobium is not used in the rare earth element mixture.

Comparative example 8

An aluminum alloy for a high-strength vehicle body is different from that of example 1 in that scandium is not used in the rare earth element mixture.

Comparative example 9

An aluminum alloy for a high-strength vehicle body is different from that of example 1 in that cobalt is not used in the rare earth element mixture.

Performance test

Test samples the high-strength aluminum alloy for vehicle bodies obtained in examples 1 to 21 was used as test samples 1 to 21, and the high-strength aluminum alloy for vehicle bodies obtained in comparative examples 1 to 9 was used as control samples 1 to 9.

The test method comprises (1) measuring the hardness of the aluminum alloy of test sample 1-21 and control sample 1-9 according to the content in YS/T420-2023 Webster hardness test method for aluminum alloy;

(2) The test samples 1-21 and control samples 1-9 were tested for yield strength according to ASTM E8/E8M;

(3) Test samples 1-21 and control samples 1-9 were tested for tensile strength according to ‌ ASTM E8/E8M;

(4) Elongation refers to the percentage of total elongation to the original gauge length of a material after stretch breaking, and if the material changes in length Δl before and after stretching, the original length is L0, then the elongation can be calculated by the formula Elongation = Δl/l0×100%.

After the above-described tests were completed in order for test samples 1 to 21 and control samples 1 to 9, the corresponding results were correspondingly recorded in table 3.

TABLE 3 test results for test samples 1-21 and control samples 1-9

Sample of	Hardness (HV)	Yield strength (MPa)	Tensile strength (MPa)	Elongation (%)
					Test sample 1	165.5	309.1	386.8	16.7
Test sample 2	163.2	306.8	384.5	14.4
					Test sample 3	163.1	306.7	384.4	14.3
Test sample 4	164.1	307.7	385.4	15.3
					Test sample 5	163.9	307.5	385.2	15.1
Test sample 6	164.3	307.9	385.6	15.5
					Test sample 7	165.3	308.9	386.6	16.5
Test sample 8	165.1	308.7	386.4	16.3
					Test sample 9	164.9	308.5	386.2	16.1
Test sample 10	163.5	307.1	384.8	14.7
					Test sample 11	163.7	307.3	385.0	14.9
Test sample 12	164.5	308.1	385.8	15.7
					Test sample 13	164.7	308.3	386.0	15.9
Test sample 14	164.0	307.6	385.3	15.2
					Test sample 15	164.2	307.8	385.5	15.4
Test sample 16	164.8	308.4	386.1	16.0
					Test sample 17	163.9	307.5	385.2	15.1
Test sample 18	164.4	308.0	385.7	15.6
					Test sample 19	165.0	308.6	386.3	16.2
Test sample 20	164.6	308.2	385.9	15.8
					Test sample 21	165.2	308.8	386.5	16.4
Control sample 1	150.8	294.4	372.1	13.1
					Control sample 2	148.4	292.1	369.7	12.8
Control sample 3	141.1	284.7	362.4	11.2
					Control sample 4	151.8	295.4	373.1	13.3
Control sample 5	152.7	296.3	374.0	13.5
					Control sample 6	152.1	295.7	373.4	13.4
Control sample 7	155.5	299.1	376.8	13.7
					Control sample 8	156.4	300.0	377.6	13.9
Control sample 9	156.1	299.7	377.4	13.8

As can be seen from the combination of example 1 and comparative examples 1 to 3 and table 3, the present application realizes good ductility of aluminum alloy under high hardness, yield strength and high tensile strength by using rare earth element mixtures composed of niobium, scandium and cobalt and co-compounding with boron, and the hardness, yield strength, high tensile strength and ductility values obtained through the above test can be significantly improved, whereas if boron or rare earth element mixtures are individually applied to aluminum alloy systems, although the corresponding effects can be improved, the improvement range is limited, the effects are far less excellent than the effects caused by the compounding of the two, and therefore, the remarkable improvement effect of 1+1>2 can be brought by the compounding of boron and rare earth element mixtures. It can be seen from the combination of comparative examples 4 to 9 and table 3 that, in the rare earth element mixture, if only any one or two of niobium, scandium and cobalt are used, the corresponding effects are limited, and only the simple superposition of the effects is achieved, and only when the three are compounded for use, the obvious corresponding effect can be brought about, so that the aluminum alloy has excellent ductility while the overall strength of the aluminum alloy is improved.

As can be seen from the combination of examples 1 and 4-6 and the combination of Table 3, the rare earth element mixture has a weight ratio of 1 (3.4-4.4) to 12-15 of niobium, scandium and cobalt, and has a stable and good application effect, wherein the rare earth element mixture has a good application effect when the weight ratio of 1:4:14 of niobium, scandium and cobalt. As can be seen from the combination of example 7 and Table 3, when the weight ratio of the boron to the rare earth element mixture is 1:5, the formed mixed system is better in the aluminum alloy, and the obtained aluminum alloy for the high-strength automobile body is better in hardness, yield strength, high tensile strength and ductility.

As can be seen from the combination of examples 1 and 8-11 and the combination of Table 3, the mass percentages of magnesium, silicon, copper and tin are 0.8-1.2% of magnesium, 1.2-1.8% of silicon, 0.6-0.8% of copper and 0.2-0.4% of tin, the formation of precipitated phases of the aluminum alloy after solution treatment can be more balanced, the subsequent aging strengthening is facilitated, and the boron and rare earth element mixed materials can be more easily matched in an alloy system, so that the aluminum alloy for the high-strength automobile body with better quality can be finally obtained.

It can be seen from the combination of examples 1 and examples 12 to 21 and the combination of Table 3 that, in the preparation of the high-strength aluminum alloy for a vehicle body of the present application, the selection and combination of the parameters in each operation can ensure the sufficient combination of the respective raw materials, exert excellent corresponding effects, and finally obtain the high-strength aluminum alloy for a vehicle body with excellent and stable quality.

The present embodiment is only for explanation of the present application and is not to be construed as limiting the present application, and modifications to the present embodiment, which may not creatively contribute to the present application as required by those skilled in the art after reading the present specification, are all protected by patent laws within the scope of claims of the present application.

Claims

1. The high-strength aluminum alloy for the vehicle body is characterized by being prepared from the following raw materials in percentage by mass:

0.5 to 1.5 percent of magnesium;

1-2% of silicon;

copper 0.4-1%;

0.1-0.5% of tin;

manganese 0.01-0.05%;

Iron 0.05-0.1%;

Boron 0.1-0.2%;

0.3 to 1.5 percent of rare earth element mixture;

the balance of aluminum;

2. The high-strength aluminum alloy for vehicle bodies according to claim 1, wherein the weight ratio of niobium, scandium, and cobalt is 1:4:14.

3. The high-strength aluminum alloy for vehicle bodies according to claim 1, wherein the weight ratio of the boron and rare earth element mixture is 1:5.

4. The high-strength aluminum alloy for a vehicle body according to claim 1, wherein the mass percentages of magnesium, silicon, copper and tin are:

0.8-1.2% of magnesium;

1.2 to 1.8 percent of silicon;

Copper 0.6-0.8%;

0.2 to 0.4 percent of tin.

5. The method for producing a high-strength aluminum alloy for vehicle bodies according to claim 1, comprising the steps of:

6. The method of producing a high-strength aluminum alloy for vehicle bodies according to claim 5, wherein in the step (2), the melting temperature is 700 to 800℃and the melting time is 2 to 3 hours.

7. The method of producing a high-strength aluminum alloy for vehicle bodies according to claim 5, wherein in the step (3), the refining temperature is 820 to 860℃and the refining time is 30 to 40 minutes.

8. The method of producing a high-strength aluminum alloy for a vehicle body according to claim 5, wherein in the step (3), the amount of the refining agent is 0.1 to 0.2% by mass of the molten metal, and the refining agent is a composition ‌ of any one or more of sodium chloride, potassium chloride, ‌ sodium fluoride and calcium fluoride ‌.

9. The method of producing a high-strength aluminum alloy for vehicle bodies according to claim 5, wherein in the step (4), the solution treatment is carried out at a temperature of 520 to 540℃for a holding time of 3 to 4 hours.

10. The method of producing a high-strength aluminum alloy for vehicle bodies according to claim 5, wherein in the step (4), the aging treatment is carried out at a temperature of 160 to 180℃for a holding time of 3 to 4 hours.