CN116103543A - A kind of recycled high thermal conductivity die-casting aluminum alloy containing rare earth elements and its preparation method - Google Patents

Abstract

The invention provides a regenerated high-heat-conductivity die-casting aluminum alloy containing rare earth elements and a preparation method thereof, wherein the chemical components of the aluminum alloy comprise Si, fe, cu, mg, zn, mn, cr, ti, ni, sn, zr, V, cd, pb, sr, la, ce and the balance of aluminum, and meanwhile, the content of single impurities is less than or equal to 0.03 percent and the total impurity content is less than or equal to 0.15 percent. Smelting the weighed raw materials according to the designed raw material dosage, slagging off for 2 times, cooling to detect components, introducing argon for refining, and pouring into ingots after final slagging off. According to the invention, the aluminum alloy is prepared by taking the waste aluminum as the raw material by utilizing the characteristic of higher waste aluminum iron content, and the consumption of pure aluminum ingots in the raw material is reduced, so that the purposes of energy conservation, emission reduction and cost control are achieved. The aluminum alloy material prepared by adding a proper amount of low-value rare earth elements lanthanum and cerium improves the performance of the aluminum alloy, has higher heat conductivity and mechanical property, and is suitable for the requirement of die casting production of aluminum alloy radiators.

Description

A kind of recycled high thermal conductivity die-casting aluminum alloy containing rare earth elements and its preparation method

technical field

The invention belongs to the technical field of aluminum alloy materials and forging, in particular to a regenerated high thermal conductivity die-casting aluminum alloy containing rare earth elements and a preparation method thereof.

Background technique

The cost of aluminum from ore to metal, and then to finished products is extremely high and consumes a lot of energy. Only one process of electrolysis to produce one ton of metal aluminum requires 13,000-15,000 kilowatt-hours of electricity. The recycling of waste aluminum alloys and aluminum shavings can greatly reduce the consumption of energy and auxiliary materials and save resource costs. Therefore, the recycling and reuse of waste aluminum alloys is of great significance in terms of saving resources, energy, and costs, shortening the production process cycle, environmental protection, and improving the human ecological environment.

Aluminum and its alloys are currently the most widely used radiator materials due to their light weight, high thermal conductivity, good formability and corrosion resistance, and low cost. Die Casting (Die Casting or High Pressure Die Casting) technology is widely used in the manufacture of aluminum alloy radiators due to its high production efficiency and the ability to produce thin-walled and complex-shaped workpieces. At present, the heat dissipation of LED lights, electronic devices, and communication equipment Devices are mostly produced using the die-casting process. The die-casting process is to apply high pressure to the molten aluminum alloy melt through the die-casting machine, so that the melt forms a pressure jet and enters and fills the cavity of the steel mold, and forms an aluminum alloy casting of a certain shape after solidification. Because the steel mold has to bear the thermal shock of the high-temperature aluminum alloy melt and the scour and friction of the high-pressure aluminum alloy fluid, the phenomenon that the aluminum alloy "sticks" to the surface of the steel mold will occur during the die-casting process, which is usually called "sticking mold". ". Adding a certain amount of iron (Fe) element to aluminum alloy can reduce the "sticking" tendency of aluminum alloy melt during die casting.

However, an excessively high iron content will form a needle-like iron-rich phase inside the solidified aluminum alloy, which will have a "splitting" effect on the aluminum alloy matrix and reduce the strength and plasticity of the aluminum alloy die-casting. Generally, scrap aluminum will inevitably contain a certain amount of iron and steel, so that the recycled aluminum produced from scrap aluminum usually has a high iron content, and the purification and removal of iron elements in recycled aluminum is difficult. The application in high-strength and high-toughness aluminum alloy materials has great potential Certain restrictions. However, the higher iron element in recycled aluminum is beneficial for die-casting aluminum alloys. Utilizing the characteristic of high iron content in recycled aluminum from waste aluminum, recycled aluminum can be used to produce high thermal conductivity die-casting aluminum alloy materials for radiators.

Contents of the invention

Aiming at the problem of low utilization rate existing in the current recycling of waste aluminum, the present invention provides a recycled high thermal conductivity die-casting aluminum alloy containing rare earth elements and a preparation method thereof. By rationally designing the alloy composition, using waste aluminum as a raw material, an appropriate amount of rare earth elements is added Lanthanum and cerium have developed a die-casting aluminum alloy material with excellent casting performance, high thermal conductivity and excellent mechanical properties, which provides a new way for the reuse of waste aluminum.

The present invention is achieved through the following technical solutions:

A recycled high thermal conductivity die-casting aluminum alloy containing rare earth elements, its chemical composition and the mass percentage of each chemical composition are as follows: Si 9.0%-12.0%, Fe 0.6%-1.2%, Cu 0.5%-3.0%, Mg 0.1%- 1.0%, Zn 0.1%～1.0%, Mn 0.05%～0.4%, Cr 0.03%～0.2%, Ti 0.05%～0.2%, Ni 0.05%～0.2%, Sn≤0.05%, Zr≤0.05%, V≤ 0.05%, Cd≤0.01%, Pb≤0.01%, Sr 0.01%～0.1%, La 0.03%～0.3%, Ce 0.03%～0.3%, other single impurity content ≤0.03%, total impurity content ≤0.15%, other The amount is aluminum.

Preferably, the chemical composition and the mass percentage of each chemical composition of the recycled high thermal conductivity die-casting aluminum alloy containing rare earth elements are as follows: Si 9.5%-11.0%, Fe 0.8%-1.1%, Cu 0.8%-1.8%, Mg 0.4%～0.8%, Zn 0.2%～0.6%, Mn 0.1%～0.25%, Cr 0.06%～0.12%, Ti 0.06%～0.12%, Ni 0.06%～0.12%, Sn≤0.03%, Zr≤0.03 %, V≤0.03%, Cd≤0.005%, Pb≤0.005%, Sr 0.01%～0.05%, La 0.06%～0.15%, Ce 0.06%～0.15%, other single impurity content ≤0.03%, total impurity content ≤ 0.15%, the balance is aluminum.

At the same time, the present invention also provides a method for preparing the regenerated high thermal conductivity die-casting aluminum alloy containing rare earth elements, comprising the following steps:

(1) Test the chemical composition of the recovered aluminum scrap, classify it according to its main chemical composition, calculate the chemical composition of the target alloy, calculate the amount of scrap aluminum, and then weigh the scrap aluminum and pure aluminum ingots in proportion , aluminum-silicon master alloy, aluminum-iron master alloy, pure copper, zinc ingot, aluminum-manganese master alloy, aluminum-titanium master alloy, aluminum-chromium master alloy, aluminum-nickel master alloy, aluminum-lanthanum master alloy, aluminum-cerium master alloy, magnesium ingot, Aluminum strontium master alloy;

(2) Put the weighed aluminum scrap, pure aluminum ingot, aluminum-silicon master alloy, aluminum-iron master alloy, pure copper, zinc ingot, aluminum-manganese master alloy, aluminum-titanium master alloy, aluminum-chromium master alloy, aluminum-nickel master alloy , aluminum-lanthanum master alloy, and aluminum-cerium master alloy are put into a smelting furnace, and the furnace charge is heated up to smelt. After melting, it is mechanically stirred for 15 to 30 minutes, then left to stand, and the slag is removed for the first time to obtain melt I, and the melt is Ⅰ Sampling for the first component testing;

(3) According to the composition test results of the melt I, supplement the elemental raw materials with insufficient content, mechanically stir for 15 to 30 minutes after the added charge is completely melted, then stand still, and carry out the second slag removal to obtain the melt II, And take a sample of the melt II for the second component detection;

(4) If the second composition test is unqualified, continue to step (3) until the composition of the melt II is qualified; if the second composition test is qualified, then cool down the melt II and add magnesium ingots and aluminum-strontium master alloys , magnesium ingots and aluminum-strontium intermediate alloys need to be pressed into the melt II for melting to melt, then mechanically stirred, then left to stand, and samples are taken for the third composition test. If the third test result meets the requirements, the obtained melt Melt III for the next step of refining operation; if the third test result does not meet the requirements, supplement the missing elements until it is qualified to obtain melt III;

(5) Refining the melt Ⅲ, passing argon gas into the melt Ⅲ, the ventilation time is 15-30 min;

(6) Stand still for 15 to 20 minutes after refining, carry out final slag removal, and then cast into ingots at a casting temperature of 690 to 710°C to obtain a recycled high thermal conductivity die-casting aluminum alloy containing rare earth elements.

The invention uses rare earth elements to purify, grain refine and modify the aluminum alloy melt, and improves the performance of the aluminum alloy by adding an appropriate amount of low-value rare earth elements lanthanum and cerium, and prepares a regenerated high thermal conductivity material containing rare earth elements using waste aluminum as a raw material. Die-cast aluminum alloy material.

The rare earth elements lanthanum (La) and cerium (Ce) have a purifying effect on aluminum alloys, mainly because the elements lanthanum (La) and cerium (Ce) can combine with hydrogen (H) elements in the aluminum alloy melt to reduce the At the same time, it combines with the inclusions in the melt to form a complex compound, which can sink to the bottom of the melting furnace after standing still and separate from the aluminum alloy melt. In addition, rare earth elements lanthanum (La) and cerium (Ce) can form a class of intermetallic compounds in the aluminum alloy system, such as Al ₁₁ La ₃ , Al ₁₁ Ce ₃ , which have the characteristics of high melting point and high thermal stability. During the solidification process, it can be used as the nucleation core of α-Al, promote the nucleation rate of α-Al grains, and have the effect of refining grains. Rare earth elements lanthanum (La) and cerium (Ce) can be enriched at the "solid-liquid" interface between eutectic silicon (Si) and aluminum melt during the solidification process of Al-Si series die-casting aluminum alloys. It hinders the growth of Si along a special crystal direction, and achieves the effect of refining and improving the shape of eutectic Si. La and Ce elements can effectively change the crystallization kinetics of the Fe-rich phase during the solidification process of the die-casting aluminum alloy, thereby changing it from a needle-like shape to a smaller fishbone shape, Chinese character shape or short rod shape, improving the plasticity of the alloy .

Rare earth elements La and Ce have the function of "fixing hydrogen" in aluminum alloys, which is mainly manifested in two aspects. One is that La and Ce elements are relatively active and have a greater affinity with H, and can form stable high-melting point compounds with hydrogen. LaH ₂ or CeH ₂ convert free hydrogen into a combined state; on the other hand, some La or Ce-rich intermetallic compound phases can chemisorb part of hydrogen and convert free hydrogen into an adsorbed state. The above two effects of La and Ce can effectively reduce free hydrogen, thereby inhibiting the formation of hydrogen during solidification, reducing the possibility of hydrogen escape in the as-cast state, and reducing the porosity of the alloy in the as-cast state. Finally, these rare earth hydrides can be separated from the melt by standing or other means, this behavior is usually called "hydrogen fixation" effect.

The inclusions in the aluminum alloy melt are mainly Al ₂ O ₃ , which will reduce the performance of the aluminum alloy. La and Ce can react with the Al ₂ O ₃ inclusions in the aluminum alloy melt to form a multi-phase material of RE-Al-O, which is denser than the aluminum melt and can sink to the crucible when left standing Bottom, achieve separation of inclusions.

Preferably, aluminum scrap accounts for 30% to 40% of the total weight of raw materials in step (1).

Preferably, the thermal conductivity of the prepared recycled high thermal conductivity die-casting aluminum alloy containing rare earth elements is not lower than 140W/mK, the tensile strength is not lower than 240MPa, and the elongation is not lower than 4.5%.

Preferably, the melting temperature of step (2) is 720-760°C.

Preferably, the melting temperature in step (3) is 720-760°C.

Preferably, the melting temperature in step (4) is 700-740°C.

Preferably, the refining temperature in step (5) is 700-740°C.

Preferably, the argon gas used in step (6) is 99.99% high-purity argon gas, so as to ensure that oxide inclusions and other impurities inside the melt can be removed to the greatest extent.

Compared with the prior art, the beneficial effects of the present invention are as follows:

1. The present invention utilizes the characteristics of high content of waste aluminum and iron, and uses waste aluminum as raw material to prepare renewable aluminum alloy materials with high thermal conductivity, reducing the amount of pure aluminum ingots in raw materials, thereby achieving energy saving and emission reduction, and cost control Purpose.

2. The present invention utilizes rare earth elements La and Ce to have the effect of "fixing hydrogen" on aluminum alloys, promoting the nucleation rate of α-Al grains and refining the eutectic Si morphology, and improving the aluminum alloy by adding an appropriate amount of low-value rare earth elements lanthanum and cerium. The properties of the alloy make the prepared aluminum alloy material have high thermal conductivity and mechanical properties, which meet the needs of die-casting production of aluminum alloy radiators.

Detailed ways

The present invention will be further described below in conjunction with specific examples.

Example 1

A recycled high thermal conductivity die-casting aluminum alloy containing rare earth elements, its chemical composition and the mass percentage of each chemical composition are as follows: Si 10.2%, Fe 0.89%, Cu 0.92%, Mg 0.46%, Zn 0.53%, Mn 0.13%, Cr 0.08%, Ti0.09%, Ni 0.06%, Sn 0.01%, Zr 0.01%, V 0.005%, Cd 0.004%, Pb 0.004%, Sr 0.02%, La0.12%, Ce 0.10%, other single impurity content ≤ 0.03%, the total impurity content is ≤0.15%, and the balance is aluminum.

Its preparation method comprises the following steps:

(1) Test the chemical composition of the recovered aluminum scrap, classify it according to its main chemical composition, calculate the chemical composition of the target alloy, calculate the amount of scrap aluminum, and then weigh the scrap aluminum and pure aluminum ingots in proportion , aluminum-silicon master alloy, aluminum-iron master alloy, pure copper, zinc ingot, aluminum-manganese master alloy, aluminum-titanium master alloy, aluminum-chromium master alloy, aluminum-nickel master alloy, aluminum-lanthanum master alloy, aluminum-cerium master alloy, magnesium ingot, Aluminum strontium master alloy;

(2) Put the weighed aluminum scrap, pure aluminum ingot, aluminum-silicon master alloy, aluminum-iron master alloy, pure copper, zinc ingot, aluminum-manganese master alloy, aluminum-titanium master alloy, aluminum-chromium master alloy, aluminum-nickel master alloy , aluminum-lanthanum master alloy, and aluminum-cerium master alloy are put into a smelting furnace, heated to 740°C to smelt the charge, and mechanically stirred for 30 minutes after melting, then left to stand for the first slag removal to obtain melt I, and the melt Body I was sampled for the first component detection;

(3) According to the composition test results of the melt Ⅰ, the elemental raw materials with insufficient content are supplemented, and the charge to be added is completely melted at 740°C, then mechanically stirred for 30 minutes, then left to stand, and the slag is removed for the second time to obtain a melt Ⅱ, and take a sample of the melt Ⅱ for the second component detection;

(4) If the second composition test is unqualified, continue to step (3) until the composition of the melt II is qualified; if the second composition test is qualified, then cool the melt II to 700°C, add magnesium ingots and aluminum Strontium master alloys, magnesium ingots and aluminum strontium master alloys need to be pressed into the melt II to be smelted to melt them, mechanically stirred, then left to stand, and samples are taken for the third composition test. If the third test results meet the requirements, then Carry out the next step of refining operation; if the third test result does not meet the requirements, it is necessary to supplement the missing elements until it is qualified to obtain melt III;

(5) Refining the melt III, passing 99.99% high-purity argon gas into the melt III for 30 minutes;

(6) Stand still for 20 min after refining, carry out final slag removal, and then cast into ingots at a casting temperature of 700 °C to obtain a recycled high thermal conductivity die-casting aluminum alloy containing rare earth elements.

Example 2

A recycled high thermal conductivity die-casting aluminum alloy containing rare earth elements, its chemical composition and the mass percentage of each chemical composition are as follows: Si 9.8%, Fe 1.05%, Cu 1.52%, Mg 0.54%, Zn 0.48%, Mn 0.21%, Cr 0.12%, Ti0.08%, Ni 0.10%, Sn 0.01%, Zr 0.01%, V 0.005%, Cd 0.004%, Pb 0.004%, Sr 0.03%, La0.11%, Ce 0.14%, other single impurity content≤ 0.03%, the total impurity content is ≤0.15%, and the balance is aluminum.

Its preparation method comprises the following steps:

(1) Test the chemical composition of the recovered aluminum scrap, classify it according to its main chemical composition, calculate the chemical composition of the target alloy, calculate the amount of scrap aluminum, and then weigh the scrap aluminum and pure aluminum ingots in proportion , aluminum-silicon master alloy, aluminum-iron master alloy, pure copper, zinc ingot, aluminum-manganese master alloy, aluminum-titanium master alloy, aluminum-chromium master alloy, aluminum-nickel master alloy, aluminum-lanthanum master alloy, aluminum-cerium master alloy, magnesium ingot, Aluminum strontium master alloy;

(2) Put the weighed aluminum scrap, pure aluminum ingot, aluminum-silicon master alloy, aluminum-iron master alloy, pure copper, zinc ingot, aluminum-manganese master alloy, aluminum-titanium master alloy, aluminum-chromium master alloy, aluminum-nickel master alloy , aluminum-lanthanum master alloy, and aluminum-cerium master alloy are put into a smelting furnace, heated to 736°C to smelt the charge, and mechanically stirred for 30 minutes after melting, then left to stand for the first slag removal to obtain melt I, and to melt Body I was sampled for the first component detection;

(3) According to the composition test results of the melt Ⅰ, the elemental raw materials with insufficient content are supplemented, and the charge to be added is completely melted at 736°C, then mechanically stirred for 30 minutes, then left to stand, and the slag is removed for the second time to obtain the melt Ⅱ, and take a sample of the melt Ⅱ for the second component detection;

(4) If the second composition test is unqualified, continue to step (3) until the composition of the melt II is qualified; if the second composition test is qualified, then cool the melt II to 713°C, add magnesium ingots and aluminum Strontium master alloys, magnesium ingots and aluminum strontium master alloys need to be pressed into the melt II for smelting to melt them, mechanically stirred, then left to stand, and samples are taken for the third composition test. If the third composition test results meet the requirements, Then proceed to the next step of refining operation, if the result of the third component test does not meet the requirements, it is necessary to supplement the missing elements until it is qualified, and obtain the melt III;

(5) Refining the melt III, passing 99.99% high-purity argon gas into the melt III for 30 minutes;

(6) Stand still for 20 minutes after refining, carry out final slag removal, and then cast into ingots at a casting temperature of 704°C to obtain a recycled high thermal conductivity die-casting aluminum alloy containing rare earth elements.

Example 3

A recycled high thermal conductivity die-casting aluminum alloy containing rare earth elements, its chemical composition and the mass percentage of each chemical composition are as follows: Si 10.9%, Fe 1.12%, Cu 1.67%, Mg 0.69%, Zn 0.56%, Mn 0.18%, Cr 0.10%, Ti0.11%, Ni 0.06%, Sn 0.01%, Zr 0.01%, V 0.005%, Cd 0.004%, Pb 0.004%, Sr 0.02%, La0.09%, Ce 0.14%, other single impurity content≤ 0.03%, the total impurity content is ≤0.15%, and the balance is aluminum.

Its preparation method comprises the following steps:

(1) Test the chemical composition of the recovered aluminum scrap, classify it according to its main chemical composition, calculate the chemical composition of the target alloy, calculate the amount of scrap aluminum, and then weigh the scrap aluminum and pure aluminum ingots in proportion , aluminum-silicon master alloy, aluminum-iron master alloy, pure copper, zinc ingot, aluminum-manganese master alloy, aluminum-titanium master alloy, aluminum-chromium master alloy, aluminum-nickel master alloy, aluminum-lanthanum master alloy, aluminum-cerium master alloy, magnesium ingot, Aluminum strontium master alloy;

(2) Put the weighed aluminum scrap, pure aluminum ingot, aluminum-silicon master alloy, aluminum-iron master alloy, pure copper, zinc ingot, aluminum-manganese master alloy, aluminum-titanium master alloy, aluminum-chromium master alloy, aluminum-nickel master alloy , aluminum-lanthanum master alloy, and aluminum-cerium master alloy are put into a smelting furnace, heated to 728°C to smelt the charge, and mechanically stirred for 30 minutes after melting, then left to stand for the first slag removal to obtain melt I, and Body I was sampled for the first component detection;

(3) According to the composition test results of the melt Ⅰ, the elemental raw materials with insufficient content are supplemented, and the charge to be added is completely melted at 728°C, then mechanically stirred for 30 minutes, then left to stand, and the slag is removed for the second time to obtain the melt Ⅱ, and take a sample of the melt Ⅱ for the second component detection;

(4) If the second composition test is unqualified, continue to step (3) until the composition of the melt II is qualified; if the second composition test is qualified, then cool the melt II to 715°C, add magnesium ingots and aluminum Strontium master alloys, magnesium ingots and aluminum strontium master alloys need to be pressed into the melt II for smelting to melt them, mechanically stirred, then left to stand, and samples are taken for the third composition test. If the third composition test results meet the requirements, Then proceed to the next step of refining operation; if the result of the third component test does not meet the requirements, it is necessary to supplement the missing elements until it is qualified to obtain the melt III;

(5) Refining the melt III, passing 99.99% high-purity argon gas into the melt III for 30 minutes;

(6) Stand still for 20 minutes after refining, carry out final slag removal, and then cast into ingots at a casting temperature of 705°C to obtain a recycled high thermal conductivity die-casting aluminum alloy containing rare earth elements.

Example 4

A recycled high thermal conductivity die-casting aluminum alloy containing rare earth elements, its chemical composition and the mass percentage of each chemical composition are as follows: Si 10.3%, Fe 1.21%, Cu 1.09%, Mg 0.48%, Zn 0.43%, Mn 0.14%, Cr 0.11%, Ti0.10%, Ni 0.09%, Sn 0.01%, Zr 0.01%, V 0.005%, Cd 0.004%, Pb 0.004%, Sr 0.02%, La0.09%, Ce 0.14%, other single impurity content ≤ 0.03%, the total impurity content is ≤0.15%, and the balance is aluminum.

Its preparation method comprises the following steps:

(1) Test the chemical composition of the recovered aluminum scrap, classify it according to its main chemical composition, calculate the chemical composition of the target alloy, calculate the amount of scrap aluminum, and then weigh the scrap aluminum and pure aluminum ingots in proportion , aluminum-silicon master alloy, aluminum-iron master alloy, pure copper, zinc ingot, aluminum-manganese master alloy, aluminum-titanium master alloy, aluminum-chromium master alloy, aluminum-nickel master alloy, aluminum-lanthanum master alloy, aluminum-cerium master alloy, magnesium ingot, Aluminum strontium master alloy;

(2) Put the weighed aluminum scrap, pure aluminum ingot, aluminum-silicon master alloy, aluminum-iron master alloy, pure copper, zinc ingot, aluminum-manganese master alloy, aluminum-titanium master alloy, aluminum-chromium master alloy, aluminum-nickel master alloy , aluminum-lanthanum master alloy, and aluminum-cerium master alloy are put into a smelting furnace, heated to 748°C to smelt the charge, and mechanically stirred for 30 minutes after melting, then left to stand for the first slag removal to obtain melt I, and to melt Body I was sampled for the first component detection;

(3) According to the composition test results of the melt Ⅰ, the elemental raw materials with insufficient content are supplemented, and the charge to be added is completely melted at 748°C, then mechanically stirred for 30 minutes, then left to stand, and the slag is removed for the second time to obtain the melt Ⅱ, and take a sample of the melt Ⅱ for the second component detection;

(4) If the second composition test is unqualified, continue to step (3) until the composition of the melt II is qualified; if the second composition test is qualified, then cool the melt II to 740°C, add magnesium ingots and aluminum Strontium master alloys, magnesium ingots and aluminum strontium master alloys need to be pressed into the melt II for smelting to melt them, mechanically stirred, then left to stand, and samples are taken for the third composition test. If the third composition test results meet the requirements, Then proceed to the next step of refining operation; if the result of the third component test does not meet the requirements, it is necessary to supplement the missing elements until it is qualified to obtain the melt III;

(5) Refining the melt III, passing 99.99% high-purity argon gas into the melt III for 30 minutes;

(6) Stand still for 20 minutes after refining, carry out final slag removal, and then cast into ingots at a casting temperature of 740°C to obtain a recycled high thermal conductivity die-casting aluminum alloy containing rare earth elements.

comparative example

A die-casting aluminum alloy material ADC12, its composition and weight percentage are: Si 12.0%, Fe 1.0%, Cu2.5%, Mg 0.5%, Zn 1.0%, Mn 0.5%, Ti 0.2%, and the balance is aluminum.

Its preparation method comprises the following steps:

(1) Put the aluminum-iron master alloy, aluminum-silicon master alloy, copper ingot and aluminum ingot into the melting furnace, the aluminum ingot is placed on the bottom and the top respectively, and the middle is followed by aluminum-silicon master alloy, aluminum-iron master alloy and copper ingot, Set the smelting temperature to 730°C, and obtain melt I after the charge is completely melted;

(2) Add aluminum-manganese master alloy to melt I for melting, set the melting temperature to 730°C, and obtain melt II after the charge is completely melted;

(3) Add magnesium ingots and zinc ingots to melt II for smelting, set the melting temperature to 730°C, and obtain melt III after the charge is completely melted;

(4) Add aluminum-titanium master alloy to melt III for melting, set the melting temperature to 730°C, and obtain melt IV after the charge is completely melted;

(5) Carry out pre-furnace composition testing on melt IV, refine melt IV after the composition is qualified, pass argon gas into melt IV, set the refining temperature to 730°C, and set the refining time to 25 min;

(6) Stand still for 18 minutes after refining, remove slag, and then cast into ingots at a casting temperature of 700°C to obtain die-casting aluminum alloy ADC12.

Performance Testing

The following tests were carried out on the recycled high thermal conductivity die-casting aluminum alloys containing rare earth elements prepared in the above-mentioned Examples 1-2 and the die-casting aluminum alloy ADC12 prepared in the comparative example:

1. Testing of thermal conductivity and mechanical properties

The thermal conductivity of the alloy was measured using a thermal conductivity tester, and the mechanical properties were measured using a tensile machine. The results are shown in Table 1.

Table 1 Test results of thermal conductivity and mechanical properties of alloy materials

Alloy materials Thermal conductivity (W/mK) Tensile strength (MPa) Elongation (%) Example 1 151 255 5.0 Example 2 146 249 6.0 ADC12 alloy 90 232 2.0

It can be seen from Table 1 that the thermal conductivity of the regenerated high thermal conductivity die-casting aluminum alloy materials containing rare earth elements obtained in Examples 1 to 2 of the present invention are all greater than 145 W/mK, far greater than the thermal conductivity of ADC12 alloy of 90 W/mK mK; in addition, its elongation is higher than that of ADC12 by 2.0%, and its tensile strength is above 240 MPa, which is higher than that of ADC12 at 232 MPa. It can be seen that the recycled high thermal conductivity die-casting aluminum alloy containing rare earth elements of the present invention not only has higher thermal conductivity, but also has better mechanical properties than ADC12 alloy.

Then use the regenerated high thermal conductivity die-casting aluminum alloys containing rare earth elements of Examples 3 to 4 to test thermal conductivity and mechanical properties, and the obtained effects are similar to those obtained in Examples 1-2, indicating that the formula and method of the present invention can obtain rare earth-containing aluminum alloys. Elements of recycled high thermal conductivity die-cast aluminum alloys have good reproducibility.

The above embodiments are only exemplary embodiments of the present invention, and are not intended to limit the present invention, and the protection scope of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent replacements to the present invention within the spirit and protection scope of the present invention, and such modifications or equivalent replacements should also be deemed to fall within the protection scope of the present invention.

Claims (10)

1. A recycled high thermal conductivity die-cast aluminum alloy containing rare earth elements, characterized in that its chemical composition and the mass percentages of each chemical composition are as follows: Si 9.0%-12.0%, Fe 0.6%-1.2%, Cu 0.5%-3.0 %, Mg 0.1%～1.0%, Zn 0.1%～1.0%, Mn 0.05%～0.4%, Cr 0.03%～0.2%, Ti 0.05%～0.2%, Ni 0.05%～0.2%, Sn≤0.05%, Zr ≤0.05%, V≤0.05%, Cd≤0.01%, Pb≤0.01%, Sr 0.01%～0.1%, La 0.03%～0.3%, Ce 0.03%～0.3%, other single impurity content ≤0.03%, total impurity Content ≤ 0.15%, the balance is aluminum. 2. The recycled high thermal conductivity die-casting aluminum alloy containing rare earth elements according to claim 1, characterized in that its chemical composition and the mass percentages of each chemical composition are as follows: Si 9.5%-11.0%, Fe 0.8%-1.1%, Cu 0.8%～1.8%, Mg 0.4%～0.8%, Zn 0.2%～0.6%, Mn 0.1%～0.25%, Cr 0.06%～0.12%, Ti 0.06%～0.12%, Ni 0.06%～0.12%, Sn ≤0.03%, Zr≤0.03%, V≤0.03%, Cd≤0.005%, Pb≤0.005%, Sr0.01%～0.05%, La 0.06%～0.15%, Ce 0.06%～0.15%, other single impurity content ≤0.03%, the total impurity content ≤0.15%, and the balance is aluminum. 3. The method for preparing the regenerated high thermal conductivity die-casting aluminum alloy containing rare earth elements according to any one of claims 1 to 2, characterized in that it comprises the following steps: (1) Detect the chemical composition of the recovered aluminum scrap, classify it according to its main chemical composition, calculate according to the chemical composition of the target alloy, and calculate the amount of waste aluminum; then weigh the waste aluminum and pure aluminum ingots in proportion , aluminum-silicon master alloy, aluminum-iron master alloy, pure copper, zinc ingot, aluminum-manganese master alloy, aluminum-titanium master alloy, aluminum-chromium master alloy, aluminum-nickel master alloy, aluminum-lanthanum master alloy, aluminum-cerium master alloy, magnesium ingot, Aluminum strontium master alloy; (2) Put the weighed aluminum scrap, pure aluminum ingot, aluminum-silicon master alloy, aluminum-iron master alloy, pure copper, zinc ingot, aluminum-manganese master alloy, aluminum-titanium master alloy, aluminum-chromium master alloy, aluminum-nickel master alloy , aluminum-lanthanum master alloy, and aluminum-cerium master alloy are put into a smelting furnace, and the furnace charge is heated up to smelt. After melting, it is mechanically stirred for 15 to 30 minutes, then left to stand, and the slag is removed for the first time to obtain melt I, and the melt is Ⅰ Sampling for the first component testing; (3) According to the result of the first component detection of the melt I, the element raw materials with insufficient content are supplemented, and the added charge is completely melted, then mechanically stirred for 15 to 30 minutes, then left to stand, and the slag is removed for the second time to obtain the melt Melt II, and take a sample of melt II for the second composition test; (4) If the second composition test is unqualified, continue to step (3) until the composition of the melt II is qualified; if the second composition test is qualified, then cool down the melt II and add magnesium ingots and aluminum-strontium master alloys , the magnesium ingot and the aluminum-strontium intermediate alloy need to be pressed into the melt II for smelting to make it melt, mechanically stirred, then left to stand, and a sample is taken for the third component test; if the third test result meets the requirements, proceed to the next step Refining operation; if the third test result does not meet the requirements, supplement the missing elements until it is qualified, and obtain melt III; (5) Refining the melt Ⅲ, passing argon gas into the melt Ⅲ, the ventilation time is 15-30 min; (6) Stand still for 15 to 20 minutes after refining, carry out final slag removal, and then cast into ingots at a casting temperature of 690 to 710°C to obtain a recycled high thermal conductivity die-casting aluminum alloy containing rare earth elements. 4. The method for preparing the recycled high thermal conductivity die-casting aluminum alloy containing rare earth elements according to claim 3, characterized in that: in step (1), aluminum scrap accounts for 30-40% of the total weight of raw materials. 5. The preparation method of the regenerated high thermal conductivity die-casting aluminum alloy containing rare earth elements according to claim 3, characterized in that: the thermal conductivity of the prepared regenerated high thermal conductivity die-casting aluminum alloy containing rare earth elements is not less than 140W/mK , the tensile strength is not less than 240MPa, and the elongation is not less than 4.5%. 6 . The method for preparing the recycled high thermal conductivity die-casting aluminum alloy containing rare earth elements according to claim 3 , wherein the melting temperature in step (2) is 720-760° C. 7. The method for preparing the recycled high thermal conductivity die-casting aluminum alloy containing rare earth elements according to claim 3, characterized in that: the melting temperature in step (3) is 720-760°C. 8 . The method for preparing the recycled high thermal conductivity die-casting aluminum alloy containing rare earth elements according to claim 3 , wherein the melting temperature in step (4) is 700-740° C. 9. The method for preparing the recycled high thermal conductivity die-casting aluminum alloy containing rare earth elements according to claim 3, characterized in that: the refining temperature in step (5) is 700-740°C. 10 . The method for preparing a recycled high thermal conductivity die-casting aluminum alloy containing rare earth elements according to claim 3 , wherein the argon gas used in step (6) is 99.99% high-purity argon gas. 11 .