WO2020103227A1

WO2020103227A1 - Rare earth magnesium alloy material having high heat dissipation performance and preparation method therefor

Info

Publication number: WO2020103227A1
Application number: PCT/CN2018/120776
Authority: WO
Inventors: 李远发; 徐涛; 樊晓泽; 尹伟; 陈善荣; 宋卓能
Original assignee: 嘉丰工业科技（惠州）有限公司
Priority date: 2018-11-19
Filing date: 2018-12-13
Publication date: 2020-05-28
Also published as: CN111197134A

Abstract

In one aspect, provided by the present invention is a rare earth magnesium alloy material having high heat dissipation performance, comprising, by mass percentage, the following components: 83.0%-92.3% of Mg, 7.0%-12.0% of Al, 0%-2.0% of Zn, 0% -2.0% of Ce, 0.1%-2.0% of La, 0%-0.6% of Mn, 0.1%-0.5% of Y, 0.01%-0.1% of Ho and 0.001-0.01% of Tm. In another aspect, disclosed by the present invention is a method for preparing the rare earth magnesium alloy material, comprising the steps of: batching, pre-heating treatment, smelting and die-casting in order. The present invention fills gaps in existing technology, enables large-scale industrial production, and allows the rare earth magnesium alloy material have both excellent mechanical properties and good thermal conductivity. The present rare earth magnesium alloy material may be used to manufacture housings of electrical products, brackets, LED radiator systems, and the like. The prepared radiator products have obvious competitive advantages over existing aluminum alloy products.

Description

Rare earth magnesium alloy material with high heat dissipation performance and preparation method thereof

Technical field

The invention belongs to the technical field of materials, and particularly relates to a rare earth magnesium alloy material with high heat dissipation performance and a preparation method thereof.

Background technique

With the development of 3C products, communication electronics, LED lighting and aerospace, the demand for heat dissipation materials in the market has increased sharply, and higher requirements have been placed on the heat dissipation performance of the materials to ensure product life and stable operation. Sex. Electronic devices are gradually developing towards thinner and thinner. The development trend of thinner and thinner requires the housing materials of electronic devices to have the characteristics of low density, high specific strength and specific heat, good shock absorption and good electromagnetic shielding performance.

Currently, copper alloys or aluminum alloys are generally used as materials for preparing electronic devices or heat sinks. Copper alloys have high costs and high densities, and cannot meet the development needs of thinning and thinning. Pure aluminum or aluminum alloy with high thermal conductivity cannot be mass-produced by die-casting process. Instead, plastic deformation is used to prepare electronic devices or radiator parts. However, radiator parts have the characteristics of multiple layers, complex structure, and thinness. The plastic deformation process is difficult and costly to manufacture radiator parts. In addition, aluminum alloys that can adopt the die casting process often need to add a large amount of Si elements, and the addition of Si elements will cause the thermal conductivity of the aluminum alloy to decrease, such as the common die-cast aluminum Alloy ADC12 has a thermal conductivity of only 96 W / (m · k).

The density of magnesium is only 1.74g / cm3, which is about 2/3 of the density of aluminum and 1/4 of the density of iron; the thermal conductivity of magnesium at 25 ℃ is 156W / (m · k), which is among the common commercial metal materials Second only to copper and aluminum; in addition, magnesium has a specific thermal conductivity comparable to that of aluminum. Therefore, magnesium has a clear competitive advantage as a material for preparing electronic devices or heat sinks. Since the tensile strength of as-cast pure magnesium is about 11.5MPa and the tensile strength of the modified pure magnesium is about 20MPa, which cannot meet the mechanical properties of the product, it is necessary to improve the mechanics of metallic magnesium through alloy strengthening Performance, but the addition of alloying elements in the metal magnesium matrix will cause a decrease in thermal conductivity. For example, at 25 ° C, the yield strength of the commonly used cast magnesium alloy AZ91D is 150MPa, but the thermal conductivity is only 72W / (m · k). Therefore, there is an urgent need to develop a new type of magnesium alloy material, which can be used as a material for preparing electronic devices or heat sinks, so that it is widely used in 3C products, communications electronics, LED lighting, aerospace and other fields.

Summary of the invention

In view of the shortcomings of the prior art, the present invention provides a rare earth magnesium alloy material with high heat dissipation performance and a preparation method thereof. By introducing rare earth elements such as lanthanum, yttrium, thulium, and holmium into a metal magnesium matrix, the magnesium alloy is improved The microstructure improves the mechanical properties and at the same time increases the heat dissipation and cooling rate of the material, making the material have superior mechanical properties and good thermal conductivity.

The present invention achieves the objective through the following technical scheme: a rare earth magnesium alloy material with high heat dissipation performance, calculated according to the mass percentage, including the following components: 83.0% -92.3% Mg, 7.0% -12.0% Al, 0% -2.0 % Zn, 0% to 2.0% Ce, 0.1% to 2.0% La, 0% to 0.6% Mn, 0.1% to 0.5% Y, 0.01% to 0.1% Ho, and 0.001 to 0.01% Tm . Ce and La have the functions of purifying the magnesium alloy melt and refining grains, thereby improving the microstructure of the magnesium alloy, and improving the mechanical properties of the magnesium alloy by precipitation strengthening. The rare earth elements Tm and Ho have the effect of increasing the rate of heat dissipation and cooling of the material, thereby improving the heat dissipation performance of the material.

Further, a rare earth magnesium alloy material with high heat dissipation performance, calculated according to the mass percentage, includes the following components: 89.0% Mg, 9.0% Al, 0.5% Zn, 0.4% Ce, 0.2% La, 0.3 % Mn, 0.15% Y, 0.05% Ho, and 0.005% Tm, the remainder being impurities.

Further, the application of the above-mentioned rare earth magnesium alloy material with high heat dissipation performance in the preparation of electrical product housings, brackets and LED radiator systems broadens the scope of application of magnesium alloys in the fields of 3C products, communications electronics, LED lighting and aerospace .

Further, the invention discloses a method for preparing a rare earth magnesium alloy material with high heat dissipation performance, which specifically includes the following steps:

S1. Prepare various raw materials according to the mass percentage of the formula. The raw materials include Mg ingot, pure Al, pure Zn, Ce-containing intermediate alloy, La-containing intermediate alloy, Mn-containing alloy or Mn block, Y-containing intermediate alloy, Ho-containing intermediate alloy and Tm master alloy;

S2. Preheat each raw material prepared in step S1 to remove moisture;

S3. Smelt the preheated raw materials in the following order: first smelt Mg ingot, pure Al and pure Zn, then add Mn-containing alloy or Mn block, La-containing intermediate alloy and Ce-containing intermediate alloy, and finally add Y-containing alloy Master alloys, Ho-containing master alloys and Tm-containing master alloys;

S4. Perform a slag removal process on the melt obtained in the smelting process;

S5. The slag-removing melt-hydraulic casting is performed to obtain a specific shape of rare earth magnesium alloy material with high heat dissipation performance.

Further, in the step S1, the Mn-containing alloy, Ce-containing intermediate alloy and La-containing intermediate alloy are respectively Mg-Mn intermediate alloy, Mg-Ce intermediate alloy and Mg-La intermediate alloy; The Y-containing intermediate alloy, Ho-containing intermediate alloy and Tm-containing intermediate alloy are Al-Y intermediate alloy, Al-Ho intermediate alloy and Al-Tm intermediate alloy, respectively.

Further, in the step S2, the preheating temperature is 200 ° C.

Further, in the step S3, the smelting process specifically includes the following steps:

S3.1. Heat the Mg ingot, pure Al and pure Zn to 350 ° C, then pass the protective gas, and continue to increase the temperature by 740 ° C to 760 ° C to obtain the melt A;

S3.2. Add Mn-containing alloy or Mn block, La-containing intermediate alloy and Ce-containing intermediate alloy to Melt A at 740 ° C to 760 ° C, stir and mix evenly to obtain Melt B;

S3.3. At 740-800 ° C, add Y-containing intermediate alloy, Ho-containing intermediate alloy and Tm-containing intermediate alloy to the melt B, stir and mix evenly to obtain a rare earth magnesium alloy melt.

Further, according to the volume fraction calculation, the protective gas includes the following components: 99.5% CO ₂ and 0.05% SF ₆ .

Further, in the step S5, the die casting molding is cold die casting, and the pouring temperature is 680 ° C.

The beneficial effects of the present invention are:

1. The present invention discloses a new type of magnesium alloy material. The magnesium alloy material introduces a variety of rare earth elements, and can achieve large-scale industrial production through a die-casting process. The tensile strength is up to 247MPa, the yield strength is up to 135MPa, and the elongation rate is Up to 5.5, with excellent comprehensive mechanical properties;

2. The magnesium alloy material of the present invention can be used for the preparation of electrical product housings, brackets, LED radiator systems and other devices. The radiator product prepared by it is heated to 200 ℃ and placed at 25 ℃, and the temperature is reduced to 40 ℃. It takes 88s, and the heat dissipation performance has obvious competitive advantages compared with the existing magnesium alloy materials;

3. The present invention uses a die-casting process to prepare magnesium alloy materials into electronic devices or radiator parts and other products, which makes up for the gaps in the existing technology. Compared with existing aluminum alloy products, it has better heat dissipation performance, reduced production difficulty, and mechanics. Features of superior performance.

BRIEF DESCRIPTION

FIG. 1 is a radiator product manufactured by the rare earth magnesium alloy material in the first embodiment.

detailed description

In order to facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings and specific embodiments. The drawings show preferred embodiments of the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field of the present invention. The terminology used in the description of the present invention herein is for the purpose of describing specific embodiments, and is not intended to limit the present invention.

Example one

This embodiment provides a rare earth magnesium alloy material with high heat dissipation performance, and discloses a preparation method of the rare earth magnesium alloy material, and a heat sink product obtained by the rare earth magnesium alloy material through a die-casting molding process. Compared with existing aluminum alloy products, the heat sink product of this embodiment has obvious competitive advantages.

The rare earth magnesium alloy material of this embodiment is calculated according to the mass percentage and includes the following components: 89.0% Mg, 9.0% Al, 0.5% Zn, 0.4% Ce, 0.2% La, 0.3% Mn, 0.15% Y, 0.05% Ho, and 0.005% Tm, with the balance being impurities.

The preparation method of the above rare earth magnesium alloy material includes the following steps:

S1. Prepare various raw materials according to the mass percentage of the above formula. The raw materials include Mg ingots with a purity of 99.9%, pure Zn with a purity of 99.9%, pure Al with a purity of 99.9%, Mg-10Mn, Al-20La, Al-25Ce, Al-10Y and Al-Ho-Tm master alloy;

S2. Preheat the prepared raw materials to remove moisture;

S3. The smelting process is performed on the preheated raw materials. The smelting sequence is: first smelt Mg ingot, pure Al and pure Zn, then add Mg-10Mn, Al-20La and Al-25Ce, and finally add Al-10Y and Al-Ho -Tm master alloy;

S4. Perform a slag removal process on the melt obtained in the smelting process to obtain a pure solution;

It should be noted that the raw materials in the step S1 are all commercially available; when preparing the Mg ingot, the scale on the surface of the Mg ingot needs to be removed first.

In the step S2, the prepared raw material is preheated to 200 ° C to remove moisture; in addition, the crucible and furnace body used for smelting are cleaned to reduce the mixing of impurities in the subsequent smelting process.

In the step S3 described above, the smelting process specifically includes the following steps:

S3.1. First put the preheated Mg ingot, pure Al and pure Zn into the crucible, heat the crucible to 350 ℃, then pass the protective gas into the crucible and continue to increase the temperature to 740 ℃ to obtain melt A ;

S3.2. At 740 ° C, add Mg-10Mn, Al-20La and Al-25Ce master alloy to the melt A and stir for 10 minutes to mix evenly to obtain melt B;

S3.3. Warm the crucible to 760 ° C, add Al-10Y and Al-Ho-Tm master alloy to the melt B and stir for 10 minutes to mix evenly, then lower the temperature to 680 ° C to obtain a rare earth magnesium alloy melt.

In the above step S3.1, calculated according to the volume fraction, the shielding gas includes the following components: 99.5% CO ₂ and 0.05% SF ₆ .

In the step S4 described above, the slag removal process uses a slag fishing or liquid extraction device to extract pure molten liquid, so as to obtain pure magnesium alloy liquid for subsequent die-casting molding process.

In the step S5, the magnesium alloy liquid molding adopts a cold die-casting process, the product mold temperature is controlled at about 200 ℃, the pouring temperature is controlled at about 680 ℃, the magnesium alloy liquid is poured into the casting chamber of the die casting machine, Die casting into the desired product shape. As shown in Figure 1, the mold is a radiator product mold, magnesium alloy liquid die-casting into a radiator product, the radiator product has a tensile strength of 247MPa, a yield strength of 135MPa, elongation of 5.5; the radiator The product is heated to 200 ° C and placed at 25 ° C. It only takes 88s to cool down to 40 ° C.

Example 2

This embodiment provides a rare earth magnesium alloy material with high heat dissipation performance, and discloses a preparation method of the rare earth magnesium alloy material, and the rare earth magnesium alloy material obtains a radiator product through a die-casting molding process.

The rare earth magnesium alloy material of this embodiment is calculated according to the mass percentage, and includes the following components: 83.7% Mg, 11.4% Al, 2.0% Ce, 1.5% La, 0.6% Mn, 0.3% Y, 0.07% Ho and 0.003% Tm, the balance is impurities.

The preparation method of the rare earth magnesium alloy material and the radiator product of this embodiment is the same as that of Embodiment 1, but there is no need to formulate, add and melt pure Zn. The performance index of the radiator product obtained by die-casting the rare earth magnesium alloy material is: tensile strength is 225MPa, yield strength is 121MPa, elongation is 6.0; the radiator product is heated to 200 ℃ and placed at 25 ℃, cooling to It only takes 95s at 40 ℃.

Example Three

The rare earth magnesium alloy material of this embodiment is calculated according to the mass percentage, and includes the following components: 91.3% Mg, 7.1% Al, 0.3% Zn, 0.8% La, 0.2% Mn, 0.25% Y, and 0.025% Ho and 0.01% Tm, the balance is impurities.

The preparation method of the rare earth magnesium alloy material and the radiator product of this embodiment is the same as that of Embodiment 1, but there is no need to formulate, add and melt the Al-25Ce master alloy. The performance index of the radiator product obtained by die-casting the rare earth magnesium alloy material is: tensile strength is 239MPa, yield strength is 130MPa, elongation is 5.8; the radiator product is heated to 200 ℃ and placed at 25 ℃, cooling to It only takes 90s at 40 ℃.

Example 4

The rare earth magnesium alloy material of this embodiment is calculated according to the mass percentage, and includes the following components: 86.8% Mg, 8.2% Al, 1.6% Zn, 1.2% Ce, 1.2% La, 0.5% Y, 0.1% Ho and 0.008% Tm, the balance is impurities.

The preparation method of the rare earth magnesium alloy material and radiator product of this embodiment is the same as that of Embodiment 1, but there is no need to formulate, add and melt Mg-10Mn. The performance index of the radiator product obtained by die-casting the rare earth magnesium alloy material is: tensile strength is 232MPa, yield strength is 128MPa, elongation is 5.9; the radiator product is heated to 200 ℃ and placed at 25 ℃, cooling to It only takes 92s at 40 ℃.

Comparative example one

AZ91D is a cast magnesium alloy commonly used in the prior art, and uses AZ91D magnesium alloy die-casting to form radiator products. The die-casting molding method and the mold used are the same as those in Embodiment 1 to Embodiment 4.

Comparative example two

ADC12 is an aluminum alloy die-casting part commonly used in the prior art, and is an Al-Si-Cu alloy. It is widely used in 3C products, communications electronics, LED lighting, aerospace and other fields. It is used to prepare electronic devices or radiator parts. Main material. The ADC12 aluminum alloy die-casting radiator product is used, the die-casting molding method and the mold used are the same as those in the first to fourth embodiments.

Six radiator products prepared from the four magnesium alloy materials of Example 1 to Example 4, the AZ91D magnesium alloy material of Comparative Example 1 and the aluminum alloy material of Comparative Example 2 were tested for mechanical properties and heat dissipation performance respectively. The heat dissipation performance test is to place six radiator products in a constant temperature furnace and heat them to 200 ℃, and then take them out and place them in a 25 ℃ environment to naturally cool down. Measure the time required for the six radiator products to cool down to 40 ℃. See table 1 for details:

Table 1 Mechanical and thermal performance test results of six radiator products

It can be seen from Table 1 that the heat dissipation performance of the heat sink products of Examples 1 to 4 has a clear competitive advantage compared to Comparative Example 1 and Comparative Example 2. Among them, the first embodiment is the best embodiment. The heat dissipation rate of the heat sink product of the first embodiment is increased by 25% compared with the comparative example 1, and increased by 14.8% compared with the comparative example 2. In addition, the radiator product of Example 1 has good mechanical properties, the tensile strength is superior to that of Comparative Example 1, and it is only 1Mpa different from that of Comparative Example 2. The yield strength of Example 1 is different from that of Comparative Example 1 and Comparative Example 2. Small; the elongation rate of Example 1 is 77.4% higher than that of Comparative Example 2, and the difference from Comparative Example 1 is small. Therefore, the overall performance index of the radiator product of the Example has obvious advantages over the existing products.

The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the principles of the present invention, several improvements and retouches can also be made, and these improvements and retouches should also be regarded as the scope of protection of the present invention.

Claims

A rare-earth magnesium alloy material with high heat dissipation performance, characterized in that, calculated according to mass percentage, it includes the following components: 83.0% -92.3% Mg, 7.0% -12.0% Al, 0% -2.0% Zn % To 2.0% Ce, 0.1% to 2.0% La, 0% to 0.6% Mn, 0.1% to 0.5% Y, 0.01% to 0.1% Ho, and 0.001 to 0.01% Tm.
The rare earth magnesium alloy material with high heat dissipation performance according to claim 1, characterized in that, calculated according to mass percentage, it includes the following components: 89.0% Mg, 9.0% Al, 0.5% Zn, 0.4% Ce, 0.2% La, 0.3% Mn, 0.15% Y, 0.05% Ho, and 0.005% Tm, the remainder being impurities.
The application of the rare-earth magnesium alloy material with high heat dissipation performance as claimed in claim 1 or 2 in electrical product housings, brackets and LED radiator systems.
A method for preparing a rare earth magnesium alloy material with high heat dissipation performance, characterized in that preparing the rare earth magnesium alloy material with high heat dissipation performance as claimed in claim 2 specifically includes the following steps:

S1. Prepare various raw materials according to the mass percentage of the formula. The raw materials include Mg ingot, pure Al, pure Zn, Ce-containing intermediate alloy, La-containing intermediate alloy, Mn-containing alloy or Mn block, Y-containing intermediate alloy, Ho-containing intermediate alloy and Tm master alloy;

S2. Preheat each raw material prepared in step S1 to remove moisture;

S3. Smelt the preheated raw materials in the following order: first smelt Mg ingot, pure Al and pure Zn, then add Mn-containing alloy or Mn block, La-containing intermediate alloy and Ce-containing intermediate alloy, and finally add Y-containing alloy Master alloys, Ho-containing master alloys and Tm-containing master alloys;

S4. Perform a slag removal process on the melt obtained in the smelting process;

S5. The slag-removing melt-hydraulic casting is performed to obtain a specific shape of rare earth magnesium alloy material with high heat dissipation performance.
The method for preparing a rare earth magnesium alloy material with high heat dissipation performance according to claim 4, characterized in that, in the step S1, the Mn-containing alloy, Ce-containing intermediate alloy and La-containing intermediate alloy are Mg- 10Mn, Al-25Ce and Al-20La master alloys; the Y-containing master alloy is Al-10Y master alloy, and the Ho-containing master alloy and Tm-containing master alloy are Al-Ho-Tm master alloys.
The method for preparing a rare earth magnesium alloy material with high heat dissipation performance according to claim 4, characterized in that, in the step S2, the preheating temperature is 200 ° C.
The method for preparing a rare earth magnesium alloy material with high heat dissipation performance according to claim 4, wherein in the step S3, the smelting process specifically includes the following steps:

S3.1. The Mg ingot, pure Al and pure Zn are heated to 350 ° C, and then the protective gas is introduced, and the temperature is further increased to 740 ° C to 760 ° C to obtain the melt A;

S3.2. Add Mn-containing alloy or Mn block, La-containing intermediate alloy and Ce-containing intermediate alloy to Melt A at 740 ° C to 760 ° C, stir and mix evenly to obtain Melt B;

S3.3. At 740-800 ° C, add Y-containing intermediate alloy, Ho-containing intermediate alloy and Tm-containing intermediate alloy to the melt B, stir and mix evenly to obtain a rare earth magnesium alloy melt.
The method for preparing a rare earth magnesium alloy material with high heat dissipation performance according to claim 7, characterized in that, according to the volume fraction calculation, the protective gas includes the following components: 99.5% CO 2 and 0.05% SF 6 .
The method for preparing a rare earth magnesium alloy material with high heat dissipation performance according to claim 4, wherein in the step S5, the die-casting is cold die-casting, and the pouring temperature is 680 ° C.