CN113862531A

CN113862531A - Aluminum alloy and preparation method thereof

Info

Publication number: CN113862531A
Application number: CN202010615956.8A
Authority: CN
Inventors: 郭强; 王梦得; 安维; 付景松
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2020-06-30
Filing date: 2020-06-30
Publication date: 2021-12-31

Abstract

In order to overcome the problem that the mechanical property requirement and the elongation rate are difficult to be considered at the same time in the existing aluminum alloy, the invention provides the aluminum alloy comprising the following components: 8-12% of Si, 0.005-0.15% of Cu, 0.2-0.5% of Mg, 0.4-0.6% of Mn, 0.08-0.3% of Fe, 0.001-0.05% of Cr, 0.08-0.12% of Ti, 0.002-0.2% of Zn, 0.005-0.04% of Sr, 0.0005-0.003% of B, 0.001-0.03% of Ga and the balance of aluminum and other elements, wherein the total amount of the other elements is less than 0.1%. Meanwhile, the invention also discloses a preparation method of the aluminum alloy. According to the aluminum alloy provided by the invention, the yield strength and the tensile strength of the aluminum alloy are remarkably improved by adjusting the proportion of each element in the aluminum alloy.

Description

Aluminum alloy and preparation method thereof

Technical Field

The invention belongs to the technical field of alloy materials, and particularly relates to an aluminum alloy and a preparation method thereof.

Background

Die casting is one of the basic forming methods of aluminum alloys and can be used for product design in complex structural members. The most common die-cast aluminum alloy is ADC12 of Ai-Si-Cu series die-cast alloy specified by Japanese Industrial Standard JISH5302, which has good material flow forming performance, large forming process window and high cost performance, and is widely applied to aluminum alloy die-cast products. And ADC12 has the advantages of low density, high specific gravity and the like, and can be used for die-casting shells, small-size thin-type brackets and the like. However, the strength of the products die-cast by ADC12 is moderate, the tensile strength is 230-250MPa, the yield strength is 160-190MPa, and the elongation is less than 3%, so that the strength and toughness indexes of products such as mobile phones, notebook computers and the like are difficult to achieve.

Because eutectic exists in the die-casting aluminum alloy, the eutectic can ensure good die-casting performance, the aluminum alloy becomes brittle along with the increase of the eutectic, and thus the mechanical property is reduced, the existing aluminum alloy material also has higher requirement on elongation, and the existing aluminum alloy is difficult to meet the requirements on the mechanical property and the elongation.

Disclosure of Invention

The invention provides an aluminum alloy and a preparation method thereof, aiming at the problem that the existing aluminum alloy is difficult to meet the strength requirement and the elongation requirement of die casting.

The technical scheme adopted by the invention for solving the technical problems is as follows:

on one hand, the invention provides an aluminum alloy which comprises the following components in percentage by mass:

8-12% of Si, 0.005-0.15% of Cu, 0.2-0.5% of Mg, 0.4-0.6% of Mn, 0.08-0.3% of Fe, 0.001-0.05% of Cr, 0.08-0.12% of Ti, 0.002-0.2% of Zn, 0.005-0.04% of Sr, 0.0005-0.003% of B, 0.001-0.03% of Ga and the balance of aluminum and other elements, wherein the total amount of the other elements is less than 0.1%.

Optionally, the aluminum alloy comprises the following components in percentage by mass:

9-11% of Si, 0.05-0.15% of Cu, 0.3-0.5% of Mg, 0.4-0.6% of Mn, 0.15-0.3% of Fe, 0.01-0.05% of Cr, 0.1-0.12% of Ti, 0.05-0.1% of Zn, 0.01-0.03% of Sr, 0.001-0.003% of B, 0.01-0.03% of Ga and the balance of aluminum and other elements, wherein the total amount of the other elements is less than 0.1%.

Optionally, in the aluminum alloy, the mass percentages of Mg, Mn, and Fe satisfy: mg + Mn + Fe > 1%.

Optionally, in the aluminum alloy, the mass percentage content ratio of Cr to Fe satisfies: cr: and (1-3) Fe is 100.

Optionally, in the aluminum alloy, the mass percentage content ratio of Mn to Fe satisfies: mn: fe ═ (2.5-2.8): 1.

optionally, in the aluminum alloy, when the mass percentage content of Mg, Mn and Fe is more than 1% < Mg + Mn + Fe < 1.7%, the mass percentage content of Sr and Si is as follows: sr: si ═ (3-6): 2000.

optionally, the other elements include one or more of Ca, Hg, Ni, In, Co, Cd, Li, Na, and P.

Optionally, in the aluminum alloy, the mass percentage content of Mn and Ga satisfies: mn: ga ═ (25-45): 1.

according to the aluminum alloy provided by the invention, the yield strength and the tensile strength of the aluminum alloy are remarkably improved by adjusting the proportion of each element in the aluminum alloy, and the elongation of the aluminum alloy can be further ensured. The aluminum alloy also has the advantages of low equipment requirement, simple heat treatment step, short and reduced production period, low gas content of castings during die-casting molding, and avoidance of high-temperature foaming and deformation problems, and has good process adaptability when applied to die-casting processes.

Optionally, the yield strength of the aluminum alloy is greater than 260MPa, the tensile strength is 345-375 MPa, the elongation is greater than 5%, and the thermal conductivity is greater than 140W/(k · m).

In another aspect, the present invention provides a method for preparing the aluminum alloy, which comprises the following steps:

weighing Al agent, Si agent, Mn agent, Cu agent, Zn agent, Ga agent, part of Fe agent and Ca agent in required proportion according to the element proportion in the aluminum alloy, and adding the Al agent, the Si agent, the Mn agent, the Cu agent, the Zn agent, the Ga agent, the part of Fe agent and the Ca agent into a smelting furnace for smelting to obtain a melt;

refining the melt by using a refining agent, removing a Ca agent, introducing inert gas, and removing scum;

weighing Mg agent in required proportion, and adding the Mg agent into the smelting furnace;

respectively weighing Sr agent, Cr agent, part of B agent and the rest of Fe agent in required proportion to perform first modification treatment;

after the first modification treatment, weighing Ti agent and the rest B agent in required parts by proportion, performing second modification treatment, degassing, and casting to obtain an aluminum alloy ingot;

and die-casting the aluminum alloy cast ingot.

Optionally, the adding mass of Ca element in the Ca agent added in the smelting process is 0.3-1%.

Optionally, the method for removing the Ca agent comprises:

adding AlF₃Removing the Ca agent;

or, chlorine or carbon tetrachloride Ca removing agent is introduced by taking the inert gas as a carrier.

Optionally, in the first modification treatment, the Sr agent, the Cr agent and the remaining Fe agent are added first, and then part of the B agent is added.

Optionally, the aluminum alloy ingot is naturally aged for 1-3d, and then is subjected to heat treatment at the treatment temperature of 170-200 ℃ in the range of 1.5-2H.

In the preparation method, the Al agent, the Si agent, the Mn agent, the Cu agent, the Zn agent, the Ga agent, part of the Fe agent and the Ca agent are added in required parts, the refining agent is added for refining and the Ca agent is removed, the Mg agent is added, the Sr agent, the Cr agent, part of the B agent and the rest of the Fe agent are added for first modification treatment, the rest of the B agent and the Ti agent are introduced for second modification treatment, and the aluminum alloy provided by the invention is obtained by casting and die-casting, and has higher mechanical property. According to the invention, a large number of experiments show that the Ca agent is introduced firstly and then removed, and the smelting efficiency can be obviously improved without introducing redundant impurities. And the modification treatment is carried out by various alloys, and further, the strength and the industrial applicability range of the aluminum alloy are enhanced.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects solved by the present invention more apparent, the present invention is further described in detail below with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The embodiment of the invention provides an aluminum alloy which comprises the following components in percentage by mass:

In the material, Si and Al form eutectic silicon and primary Si, and dispersed primary Si and fine alpha-Al crystal grains can be formed under the action of Sr element, so that the strength and the fluidity of the material are improved.

And trace Cu can be well dissolved in alpha-Al matrix grains in a solid mode, so that the elongation of the alloy can be ensured, and the yield strength of the material can be improved.

In the invention, Mg can react with Si and Mg respectively to generate strengthening phase Mg₂Si and a strengthening phase MgZn₂Strengthening phase Mg₂Si can enhance the strength and toughness of the alloy and strengthen the phase MgZn₂Uniformly dispersed and distributed at the crystal boundary to promote the crystal boundaryTherefore, the yield strength of the material is improved.

Mn and Cr are dissolved in the aluminum alloy matrix in a solid mode, and the performance of the matrix can be enhanced. Mn and Cr inhibit the growth of primary Si and alpha-Al crystal grains, so that the primary Si content is dispersed among the crystal grains, the dispersion strengthening effect is achieved, and the strength and the toughness of the alloy are improved.

Fe reduces the mucosa property of the die casting alloy, and when the content of Fe is 0.08-0.3%, the Fe is inhibited from forming needles, and the heat conduction is reduced; fe can also react with Si and matrix Al to generate strengthening phase Al₁₂Fe₃Si, and the alloy strength is improved.

The Ti has two main effects that firstly, the Ti has the grain refining effect, the alloy material can obtain higher strength and elongation after being refined, the thermal expansion coefficient of the alloy is small, and the casting performance is good; secondly, Ti can form intermetallic compounds in the alloy, so that the structure of the alloy is changed in complexity.

Ti and B are dispersed among the crystal grains, so that primary crystal silicon can be uniformly distributed in alpha-Al, the growth of the alpha-Al is greatly inhibited, and the strength of the alloy is improved.

In some preferred embodiments, the aluminum alloy comprises the following components in percentage by mass:

9-11% of Si, 0.05-0.15% of Cu, 0.3-0.5% of Mg, 0.4-0.6% of Mn, 0.2-0.3% of Fe, 0.01-0.05% of Cr, 0.1-0.12% of Ti, 0.05-0.1% of Zn, 0.01-0.03% of Sr, 0.001-0.003% of B, 0.01-0.03% of Ga and the balance of aluminum and other elements, wherein the total amount of the other elements is less than 0.1%.

In other specific embodiments, the content of Si is 8%, 8.6%, 9.5%, 10.2%, 11.4% or 12%, the content of Cu is 0.005%, 0.013%, 0.02%, 0.07%, 0.1% or 0.15%, the content of Mg is 0.2%, 0.3% or 0.5%, the content of Mn is 0.4%, 0.5% or 0.6%, the content of Fe is 0.08%, 0.1%, 0.2% or 0.3%, the content of Cr is 0.001%, 0.004%, 0.01%, 0.02% or 0.05%, the content of Ti is 0.08%, 0.1%, 0.11% or 0.12%, the content of Zn is 0.002%, 0.005%, 0.01%, 0.015% or 0.2%, the content of Sr is 0.005%, 0.009%, 0.02%, 0.03% or 0.04%, the content of B is 0.0005%, 0.008%, 0.0008%, 0.008% or 0.014%, the total content of other elements is less than 0.003%, the content of Ga is 0.01%, the balance is 0.03%, 0.002%, 0.003%, 0.01% or 0.2% of the content of Ga.

In some embodiments, the Mg, Mn, and Fe are present in a mass percent ratio of: mg + Mn + Fe > 1%.

Further experiments by the inventors have found that when the mass content of Mn is larger than that of Fe in Mg, Mn and Fe at this ratio, the production of an AlFeSi phase is suppressed, and the strength of the alloy can be improved.

In some embodiments, the ratio of the mass percent of Cr to the mass percent of Fe satisfies: cr: and (1-3) Fe is 100.

When the mass percentages of Cr and Fe satisfy the above ranges, Cr can combine with AlFeSi to form AlCrSi and (CrFe) Al₇The intermetallic compound can further prevent the formation of needle-shaped AlFeSi phase, reduce the sensitivity of stress corrosion cracking and improve the elongation of the alloy. The content of Cr element is higher than that of Cr: when the content ratio of Fe to (1-3) is 100, the die sticking phenomenon is easy to occur, and the Cr content is lower than that of Cr: when the content ratio of Fe to (1-3):100 is less, the Cr element content is less, and the Cr element cannot effectively replace the Fe element, so that the effective grain refining effect is difficult to play, the stress corrosion cracking sensitivity is reduced, and the quenching sensitivity is increased.

In some embodiments, the ratio of the mass percent of Mn to Fe satisfies: mn: fe ═ (2.5-2.8): 1.

when the content of Mg is 0.2% to 0.5%, Mn in this range can combine with Fe element not combined with Si element to form (Mn, Fe) Al₆. Fe and Mn have high melting points and are easy to combine with Si, and crystals are very fine when separated out to form fibrous (FeMn)₃SiAl₁₂The phase is subjected to heat treatment (such as the temperature of 150-.

In some embodiments, when the Mg, Mn, and Fe content by mass satisfies 1% < Mg + Mn + Fe < 1.7%, the Sr and Si content by mass satisfies: sr: si ═ (3-6): 2000.

in the mass ratio of Sr to Si within the range, Si forms lamellar eutectic Si under the action of Sr element, primary crystal Si does not generally occur, and the lamellar eutectic Si can be rounded and fiberized, so that the strength of the alloy is improved.

In some embodiments, the other elements include one or more of Ca, Hg, Ni, In, Co, Cd, Li, Na, and P.

In some embodiments, the mass percent content of Mn and Ga satisfies: mn: ga ═ (25-45): 1.

when the mass percentage of Mn to Ga is within the above range, Mn can produce strengthening effect while reducing the enrichment of Ga at grain boundaries. And in the proportion, the Fe is not enriched at the alpha-Al crystal boundary, so that Ga in the area can be distributed in a dispersion shape, segregation is not generated, and the tendency of the Rehbinder effect of the aluminum alloy is reduced.

In some embodiments, the aluminum alloy has a yield strength greater than 260MPa, a tensile strength of 345-375 MPa, an elongation > 5%, and a thermal conductivity greater than 140W/(k-m).

The embodiment of the invention also provides a preparation method of the aluminum alloy, which comprises the following operation steps:

and die-casting the aluminum alloy cast ingot.

In the present invention, the Al agent, Si agent, Cu agent, Mg agent, Mn agent, Fe agent, Cr agent, Ti agent, Zn agent, Sr agent, B agent, and Ga agent are materials capable of providing various elements necessary for preparing the die-casting aluminum alloy of the present invention, and may be an intermediate alloy, a metal compound, or a pure metal containing the above elements as long as the composition components in the aluminum alloy obtained after melting the added aluminum alloy raw material are within the above ranges.

According to the preparation method, the Al agent, the Si agent, the Mn agent, the Cu agent, the Zn agent, the Ga agent, a part of the Fe agent and the Ca agent are added in required parts, the refining agent is added for refining and the Ca agent is removed, the Mg agent is added, the Sr agent, the Cr agent, a part of the B agent and the rest of the Fe agent are added for first modification treatment, the rest of the B agent and the Ti agent are introduced for second modification treatment, and the aluminum alloy obtained by casting and die casting can meet the requirement of die casting and can still have high mechanical property after the aluminum alloy is die-cast. According to the invention, a large number of experiments show that the Ca agent is introduced firstly and then removed, and the smelting efficiency can be obviously improved without introducing redundant impurities. And the modification treatment is carried out by various alloys, and further, the strength and the industrial applicability range of the aluminum alloy are enhanced.

Because the Mg agent is easy to oxidize in the smelting process and is easy to remove in the refining process, the Mg agent is added after the refining process, so that the content of Mg element in the aluminum alloy can be accurately controlled, and the utilization efficiency of the raw materials is improved.

In some embodiments, the added mass of Ca element in the Ca agent added during smelting is 0.3 to 1%.

In some embodiments, the method of removing a Ca agent comprises:

adding AlF₃Removing the Ca agent;

In the present invention, AlF can be introduced₃Reacting with Ca agent to generate CaF₂And new impurities are not introduced.

The Ca agent is a Ca-containing master alloy or a Ca-containing metal compound.

In some embodiments, in the first deterioration treatment, the Sr agent, the Cr agent, and the remaining Fe agent are added first, and then part of the B agent is added.

The Sr agent, the Cr agent and the residual Fe agent are preferentially added, and then part of the B agent is added, so that the modification effect of the aluminum liquid can be effectively improved, and the strength of the aluminum alloy is enhanced.

In some embodiments, the aluminum alloy ingot is naturally aged for 1-3 days and then heat treated at a 1.5-2H treatment temperature of 170-.

After the heat treatment at the treatment temperature of between 1.5 and 2H and 200 ℃, Cu can generate trace amount of fine Al through segregation among alpha-Al crystals₂And the Cu phase ensures the elongation of the material and simultaneously improves the yield strength of the material.

In some embodiments, the Sr agent and the remaining Fe agent are an Al-Fe-Sr alloy, the Cr agent is an Al-Cr 5% alloy, and the partial B agent is an Al-B3% alloy;

the Ti agent and the residual B agent are Al-Ti-B alloy.

The sum of the content percentages of the elements of the added master alloy or the added simple substance metal is within the content range of the aluminum alloy component provided by the invention.

After the first modification treatment is finished, Al-Ti-B is added to perform second modification treatment, so that on one hand, the content of the B element in the alloy can be accurately controlled, and simultaneously, the modification improvement effect of the added Sr and Cr on the alloy is improved.

In some embodiments, the refining agent comprises one or both of hexafluoroethane, an aluminum refining agent ZS-AJ 01C;

the inert gas comprises nitrogen and/or argon.

More preferably, the inert gas is nitrogen.

In some embodiments, the temperature of the refining is 730-.

In some embodiments, in the step of die-casting and forming the aluminum alloy ingot, the die-casting temperature is 680-720 ℃, the speed of a die-casting machine is 1.6-2m/s, and the holding time is 1-3 s.

The present invention will be further illustrated by the following examples.

Table 1 shows the mass percentages (%) of the components of the aluminum alloy of the present invention, wherein the total mass of the aluminum alloy is 100%, and the mass percentages of the remaining components, excluding the components shown in Table 1, are Al.

TABLE 1

Example 1

This example is used to illustrate the aluminum alloy and the method of making the same disclosed in the present invention, and includes the following steps:

as shown in Table 1, the aluminum alloy comprises the following components in percentage by mass: the aluminum alloy comprises, by mass, 10% of Si, 0.1% of Cu, 0.3% of Mg, 0.5% of Mn, 0.25% of Fe, 0.007% of Cr, 0.1% of Ti, 0.1% of Zn, 0.02% of Sr, 0.002% of B and 0.015% of Ga, wherein the mass of various intermediate alloys or metal simple substances required by the mass content of the aluminum alloy components is calculated, the balance is Al and other elements, the total amount of the other elements is less than 0.1%, and the aluminum alloy is added and operated according to the following steps:

step 1: when the furnace temperature is 200-300 ℃, adding pure aluminum;

step 2: when the temperature of the furnace rises to about 700 ℃, adding a Si agent and a Ca agent of Ca element with the mass percent of 0.5 percent of melt (the Ca agent is a Ca-containing intermediate alloy or a Ca-containing metal compound);

and step 3: when the furnace temperature reaches 800-850 ℃, adding a Mn agent, a Cu agent, a Zn agent, a Ga agent and part of Fe agent according to the mass percentage, stirring and standing after melting, wherein the stirring and standing are alternately carried out for 3 times, the stirring time is 3min each time, and the standing time is 8 min;

and 4, step 4: adding the remaining pure aluminum, and adjusting the smelting temperature to 760 ℃;

and 5: refining the melt by using a refining agent, and removing the excessive Ca agent (adding AlF) according to the mass percentage₃Removing the Ca agent, or introducing inert gas as a carrier, introducing chlorine or carbon tetrachloride to remove the Ca agent), blowing nitrogen or argon together into the melt at the temperature of 730-;

step 6: adding Mg, detecting the components of the molten metal, and performing subsequent steps after the molten metal is adjusted to be qualified;

and 7: when the temperature is 700-740 ℃, adding a modifier to modify the melt, and respectively adding Al-Fe-Sr intermediate alloy, Al-Cr 5% intermediate alloy and Al-B3% intermediate alloy according to the mass percentage, wherein the Al-Fe-Sr intermediate alloy and the Al-Cr 5% intermediate alloy are preferentially added;

and 8: after modification is finished, adding Al-Ti-B intermediate alloy according to the mass percentage, modifying, and finally removing gas and pouring materials;

and step 9: and carrying out die casting process on the aluminum alloy ingot, wherein the die casting temperature is 680-720 ℃, the speed of a die casting machine is 1.6-2m/s, and the heat preservation time is 1-3 s.

Step 10: after die casting and forming, naturally aging for 1-3d, then carrying out heat treatment at the treatment temperature of 170-2H and 200 ℃, and placing the product for 1-3 d.

Examples 2 to 32

Examples 2-32, which illustrate the aluminum alloys and methods of making the same disclosed in the present invention, include most of the steps of example 1, except that:

the aluminum alloy compositions shown in examples 2 to 32 in Table 1 were used, and the other operation steps were the same as in example 1.

Example 33

Example 33 is provided to illustrate an aluminum alloy and a method of making the same, including most of the operations of example 1, except that:

the aluminum alloy composition shown in example 33 in Table 1 was used;

step 2: when the temperature of the furnace rises to about 700 ℃, adding the Si agent according to the mass percentage;

and 5: refining the melt by using a refining agent, blowing nitrogen or argon into the melt at the temperature of 730-.

Example 34

Example 34 is intended to illustrate an aluminum alloy and method of making the same, as disclosed in the present invention, including most of the operating steps of example 1, except that:

the aluminum alloy composition shown in example 34 in Table 1 was used;

and 7: when the temperature is 700-740 ℃, adding a modifier to modify the melt, and adding Al-Ti-B intermediate alloy according to the mass percentage;

and 8: after modification is finished, respectively adding Al-Fe-Sr intermediate alloy, Al-Cr 5% intermediate alloy and Al-B3% intermediate alloy according to mass percentage, wherein the Al-Fe-Sr intermediate alloy and the Al-Cr 5% intermediate alloy are preferentially added, modifying, and finally removing gas and casting materials.

Example 35

Example 35 is provided to illustrate an aluminum alloy and a method of making the same, including most of the operations of example 1, except that:

the aluminum alloy composition shown in example 35 in Table 1 was used;

and step 3: when the furnace temperature reaches 800-850 ℃, adding a Mn agent, a Cu agent, a Zn agent, a Ga agent, a Cr agent and part of Fe agent according to mass percentage, stirring and standing after melting, wherein the operation is carried out for 3 times alternately, the stirring time is 3min each time, and the standing time is 8 min;

and 7: when the temperature is 700-740 ℃, adding a modifier to modify the melt, and respectively adding an Al-Fe-Sr intermediate alloy and an Al-B3% intermediate alloy according to the mass percentage, wherein the Al-Fe-Sr intermediate alloy is preferentially added;

and 8: after modification is finished, adding Al-Ti-B intermediate alloy according to the mass percentage, modifying, and finally removing gas and pouring materials.

Comparative examples 1 to 22

Comparative examples 1-22 are provided to illustrate by way of comparison the aluminum alloy and method of making disclosed herein, including most of the operating steps of example 1, except that:

the aluminum alloy compositions shown in comparative examples 1 to 22 in Table 1 were used, and the other operation steps were the same as in example 1. Performance testing

The following performance tests were performed on the aluminum alloys prepared in the above examples 1 to 35 and comparative examples 1 to 22: tensile Strength test

Part 1 of the GBT 228.1-2010 metal material tensile test was used: room temperature test method for tensile strength, yield strength and elongation of the material.

The aluminum alloy prepared from the components in table 1 was die-cast to form tensile test bars (diameter 6.4mm x gauge length 50mm), an electronic universal tester of the type CMT5105 was used for tensile property testing, the gauge length was 50mm, the loading rate was 2mm/min, the measurement data was recorded, six samples were tested at each formulation point, wherein the yield strength, the tensile strength and the elongation were the average of six data, the relative standard deviation of the yield strength was the percentage ratio of the standard deviation to the average of 6 yield strength data, and the relative standard deviation of the tensile strength was the percentage ratio of the standard deviation to the average of 6 tensile strength data.

And (3) testing thermal conductivity:

preparing an aluminum alloy into a cast ingot heat-conducting wafer with the diameter of 12.7 multiplied by 3mm, and uniformly spraying graphite coatings on two surfaces of a sample to be tested; and placing the processed sample into a laser thermal conductivity instrument for testing. The laser thermal conductivity test was carried out according to ASTM E1461 Standard method for measuring thermal diffusivity by flashing light.

The test results obtained are filled in table 2.

TABLE 2

As can be seen from the test results of table 2:

the test results of the comparative examples 1 to 35 and the comparative examples 1 to 22 show that, compared with the aluminum alloy outside the element range provided by the invention, the aluminum alloy provided by the invention has better yield strength and tensile strength, and the elongation is improved, so that the requirement of a die casting process can be met, and meanwhile, the aluminum alloy has better heat conduction performance, and is suitable for material application with higher heat conduction requirement.

As is apparent from the results of the tests of comparative examples 1 to 23 and example 24, when the sum of the contents of Mg, Mn and Fe in percentage by mass in the material composition is more than 1%, the improvement of the strength of the aluminum alloy is facilitated.

As is apparent from the results of the tests conducted for comparative examples 1 to 23 and examples 25 to 26, when the material composition contains Cr and Fe in the range of 1: within 100-3:100, the elongation of the alloy is improved, and the die is not easy to clamp.

As is apparent from the results of the tests conducted for comparative examples 1 to 23 and examples 27 to 28, when the Mn and Fe content in the material composition is in the range of Mn: fe ═ 2.5: 1-2.8:1, and the elongation of the alloy is improved while the alloy strength is ensured.

As is apparent from the results of the tests of comparative examples 1 to 23 and examples 29 to 30, when the content percentages of Mg, Mn and Fe of the material components satisfy 1% < Mg + Mn + Fe < 1.7%, the mass contents of Sr and Si in the material components are in the range of 3: 2000-6:2000, the strength of the alloy is improved.

As is apparent from the results of the tests conducted for comparative examples 1 to 23 and examples 31 to 32, when the material composition contains Mn and Ga in the following percentages by mass: mn: ga ═ (25-45): 1, the performance of the aluminum alloy is significantly improved.

The test results of comparative example 1 and example 33 show that the addition of the Ca agent can significantly shorten the melting time, which is beneficial to improving the melting efficiency, and meanwhile, the Ca agent is removed in the subsequent operation, so that the influence of Ca on the performance of the aluminum alloy can be avoided.

The test results of the comparative example 1 and the examples 34 to 35 show that the material addition sequence of the modification link has a great influence on the performance of the aluminum alloy, and the performance of the aluminum alloy can be effectively improved by the addition sequence of the preparation method provided by the invention.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. The aluminum alloy is characterized by comprising the following components in percentage by mass:

2. The aluminum alloy of claim 1, wherein the aluminum alloy comprises the following components in percentage by mass:

3. The aluminum alloy of claim 1, wherein the aluminum alloy has a mass percent content of Mg, Mn, and Fe that satisfies: mg + Mn + Fe > 1%.

4. The aluminum alloy of claim 1, wherein the aluminum alloy has a ratio of the mass percentages of Cr and Fe that satisfies: cr: and (1-3) Fe is 100.

5. The aluminum alloy of claim 3, wherein the aluminum alloy has a ratio of Mn to Fe in mass percent that satisfies: mn: fe ═ (2.5-2.8): 1.

6. the aluminum alloy according to claim 1, wherein when the mass percentage content of Mg, Mn, and Fe satisfies 1% < Mg + Mn + Fe < 1.7%, the mass percentage content of Sr and Si satisfies: sr: si ═ (3-6): 2000.

7. the aluminum alloy of claim 1, wherein the other elements comprise one or more of Ca, Hg, Ni, In, Co, Cd, Li, Na, and P.

8. The aluminum alloy of any one of claims 1 to 7, wherein the mass percent contents of Mn and Ga satisfy: mn: ga ═ (25-45): 1.

9. the aluminum alloy of any of claims 1 to 7, having a yield strength greater than 260MPa, a tensile strength of 345 to 375MPa, an elongation > 5%, and a thermal conductivity greater than 140W/(k-m).

10. The method for preparing an aluminum alloy according to any one of claims 1 to 9, comprising the following steps:

and die-casting the aluminum alloy cast ingot.

11. The method of producing an aluminum alloy as recited in claim 10, wherein the Ca element in the Ca agent added during the melting is added in an amount of 0.3 to 1% by mass.

12. The method of producing an aluminum alloy according to claim 10, wherein the method of removing the Ca agent comprises:

adding AlF₃Removing the Ca agent;

13. The method of producing an aluminum alloy according to claim 10, wherein in the first modification treatment, the Sr agent, the Cr agent, and the remaining Fe agent are added first, and then a part of the B agent is added.

14. The method for preparing an aluminum alloy as recited in claim 10, wherein the aluminum alloy ingot is naturally aged for 1-3 days and then subjected to a heat treatment at a treatment temperature of 1.5-2H of 170-200 ℃.