WO2018228059A1

WO2018228059A1 - High thermal conductivity magnesium alloy, inverter housing, inverter and automobile

Info

Publication number: WO2018228059A1
Application number: PCT/CN2018/084488
Authority: WO
Inventors: 郭强; 曹梦梦; 巩泉雨
Original assignee: 比亚迪股份有限公司
Priority date: 2017-06-15
Filing date: 2018-04-25
Publication date: 2018-12-20
Also published as: CN109136699B; EP3640356A4; CN109136699A; EP3640356B1; US20210147963A1; EP3640356A1

Abstract

A high thermal conductivity magnesium alloy, an inverter housing, an inverter and an automobile, the high thermal conductivity magnesium alloy comprising: 2.0 to 4.0 weight % of Al, 0.1 to 0.3 weight% of Mn, 1.0 to 2.0 weight % of La, 2.0 to 4.0 weight % of Ce, 0.1 to 1.0 weight % of Nd, 0.5 to 2.0 weight% of Zn, 0.1 to 0.5 weight % of Ca, less than 0.1 weight % of Sr, less than 0.1 weight % of Cu, and balance of magnesium.

Description

High thermal conductivity magnesium alloy, inverter housing, inverter and car

Cross-reference to related applications

The present application claims priority to Chinese Patent Application No. PCT Application No.

Technical field

The present application relates to the field of material technology, and in particular to a high thermal conductivity magnesium alloy and its application, and more particularly to a high thermal conductivity magnesium alloy, at least a portion of an inverter housing formed of the above high thermal conductivity magnesium alloy, including the above inverter An inverter of the housing and a car including the above inverter.

Background technique

The conventional die-cast magnesium alloy currently available on the market is AZ91D, and its main components are: Al: 8.5 to 9.5%, Zn: 0.45 to 0.90%, Mn: 0.17 to 0.4%, Si: ≤ 0.05%, Cu: ≤ 0.025%, Ni: ≤ 0.001%, Fe: ≤ 0.004%, and the balance is magnesium. The material has good flow forming performance, low cost and high mechanical properties, but the thermal conductivity is small, only <60W/m.K, which limits the wide application of magnesium alloy materials.

Therefore, the current research on magnesium alloys still needs to be improved.

Summary of the invention

The present application aims to solve at least one of the technical problems in the related art to some extent. To this end, an object of the present application is to propose a die-cast magnesium alloy having good thermal conductivity or at the same time having desirable mechanical properties.

In one aspect of the present application, the present application provides a high thermal conductivity magnesium alloy. According to an embodiment of the present application, the high thermal conductivity magnesium alloy comprises: 2.0 to 4.0% by weight of Al, 0.1 to 0.3% by weight of Mn, 1.0 to 2.0% by weight of La, based on the total mass of the high thermal conductivity magnesium alloy, 2.0 to 4.0% by weight of Ce, 0.1 to 1.0% by weight of Nd, 0.5 to 2.0% by weight of Zn, 0.1 to 0.5% by weight of Ca, less than 0.1% by weight of Sr, less than 0.1% by weight of Cu, and the balance magnesium. The inventors have found that a magnesium alloy containing the above components has a very high thermal conductivity and an excellent mechanical property, and can be effectively used in conditions and environments requiring high thermal conductivity and light weight, such as for manufacturing automobiles. The inverter housing and the like greatly expand the application range of the magnesium alloy.

In another aspect of the present application, the present application provides an inverter housing. According to an embodiment of the present application, at least a portion of the inverter housing is formed from the high thermal conductivity magnesium alloy previously described. Thus, the inverter housing has a very high thermal conductivity and has very good heat dissipation performance, so that the safety and service life of the inverter using the inverter housing are significantly improved.

In yet another aspect of the present application, the present application provides an inverter. According to an embodiment of the present application, the inverter includes the inverter housing described above. The inventor found that the inverter has good heat dissipation performance, the safety of use is obviously improved, and the service life is significantly prolonged.

In yet another aspect of the present application, the present application provides an automobile. According to an embodiment of the present application, the automobile includes the inverter described above. The vehicle has all of the features and advantages of the previously described inverter and will not be described again.

detailed description

Embodiments of the present application are described in detail below. The embodiments described below are illustrative and are merely illustrative of the present application and are not to be construed as limiting. Where specific techniques or conditions are not indicated in the examples, they are carried out according to the techniques or conditions described in the literature in the art or in accordance with the product specifications. The reagents or instruments used are not indicated by the manufacturer, and are conventional products that can be obtained commercially.

According to an embodiment of the present application, in the above magnesium alloy, aluminum can improve the strength and corrosion resistance of the magnesium alloy; manganese can increase the elongation and toughness of the magnesium alloy; and addition of rare earth elements such as La, Ce, Nd can significantly improve magnesium The high temperature performance of the alloy, and in the casting process can also significantly refine the magnesium alloy particles, and magnesium can form a solid solution with the above rare earth elements, and the magnesium-rich region is a low melting point simple eutectic, and is distributed in a network at the grain boundary. The formation of micropores is inhibited, thereby improving the casting properties and thermal conductivity of magnesium alloys. Among them, Nd has a great influence on the fine grain strengthening of magnesium alloys, and the refinement effect of Ce on microstructures is beneficial to improve the mechanical properties and corrosion resistance of magnesium alloys. Zinc can exert solid solution strengthening and form a strengthening phase; adding a small amount of Ca and Sr can prevent oxidation of the magnesium alloy during the melting process. The inventors mix the above components in the above ratio to form a magnesium alloy, and the components cooperate with each other, and the obtained magnesium alloy has excellent thermal conductivity and mechanical properties at the same time, and can be effectively applied to various fields, particularly for thermal conductivity. Higher demand situation.

According to an embodiment of the present application, in order to further improve the use performance of the magnesium alloy, the magnesium alloy may include: 0.15 to 0.3% by weight of Mn, and 2.5 to 4.0% by weight of Ce based on the total mass of the high heat conductive magnesium alloy. Therefore, the magnesium alloy can have the desired thermal conductivity while having good mechanical properties, so as to better meet the requirements of different working environments and conditions.

According to a specific embodiment of the present application, based on the total mass of the high thermal conductivity magnesium alloy, the magnesium alloy may include: 3.0 wt% Al, 0.25 wt% Mn, 1.55 wt% La, 3.0 wt% Ce 0.13 wt% Nd, 0.6 wt% Zn, 0.15 wt% Ca, less than 0.1 wt% Sr, less than 0.1 wt% Cu, and the balance magnesium.

According to another embodiment of the present application, based on the total mass of the high thermal conductivity magnesium alloy, the magnesium alloy may include: 2.0% by weight of Al, 0.15% by weight of Mn, 2.0% by weight of La, and 2.5% by weight. Ce, 0.1% by weight of Nd, 2.0% by weight of Zn, 0.1% by weight of Ca, less than 0.1% by weight of Sr, less than 0.1% by weight of Cu, and the balance of magnesium.

According to another embodiment of the present application, the magnesium alloy may include: 4.0% by weight of Al, 0.1% by weight of Mn, 1.0% by weight of La, 2.0% by weight based on the total mass of the high thermal conductivity magnesium alloy. Ce, 1.0% by weight of Nd, 0.5% by weight of Zn, 0.5% by weight of Ca, less than 0.1% by weight of Sr, less than 0.1% by weight of Cu, and the balance of magnesium.

According to another embodiment of the present application, based on the total mass of the high thermal conductivity magnesium alloy, the magnesium alloy may include: 2.5% by weight of Al, 0.3% by weight of Mn, 1.0% by weight of La, 4.0% by weight Ce, 0.5% by weight of Nd, 1.5% by weight of Zn, 0.3% by weight of Ca, less than 0.1% by weight of Sr, less than 0.1% by weight of Cu, and the balance of magnesium.

The inventors have found that a magnesium alloy having the above formulation has excellent thermal conductivity and excellent mechanical properties.

The inventors have found through extensive experiments that the magnesium alloy according to the embodiment of the present application has significantly better thermal conductivity than the existing magnesium alloy, and the experimental results show that the thermal conductivity of the magnesium alloy having the above composition and ratio can be greater than 110 w/mk. . Therefore, the magnesium alloy can be effectively applied to various environments having high requirements for thermal conductivity, and the magnesium alloy has low density, high specific strength, large specific modulus, good shock absorption, and resistance to organic matter and alkali. The corrosion performance is good and so on.

In addition, the magnesium alloy according to an embodiment of the present application may further satisfy at least one of the following conditions: tensile strength greater than 220 MPa; yield strength greater than 150 MPa; and elongation greater than 4%. Specifically, the magnesium alloy may satisfy only one of the above conditions, such as satisfying only the tensile strength greater than 220 MPa, satisfying only the yield strength greater than 150 MPa, or only satisfying the elongation greater than 4%; and simultaneously satisfying the above two conditions, such as simultaneously satisfying The tensile strength is greater than 220 MPa and the yield strength is greater than 150 MPa, while the tensile strength is greater than 220 MPa and the elongation is greater than 4%, or both the yield strength is greater than 150 MPa and the elongation is greater than 4%; and the tensile strength is greater than 220 MPa, The yield strength is greater than 150 MPa and the elongation is greater than 4%. Therefore, the magnesium alloy has good thermal conductivity and mechanical properties, and can meet the requirements of different fields and different working environments and conditions.

According to the embodiment of the present application, the specific structure and the like of the inverter housing are not particularly limited, and may be any inverter housing structure known in the art, and can be flexibly selected by those skilled in the art according to actual needs. Moreover, a part of the inverter housing, such as a portion requiring high thermal conductivity, is prepared by the magnesium alloy of the present application, or the inverter housing may be entirely prepared by the magnesium alloy of the present application, and those skilled in the art may also according to the cost. Flexible choices such as usage requirements.

In yet another aspect of the present application, the present application provides an inverter. According to an embodiment of the present application, the inverter includes the inverter housing described above. The inventor found that the inverter has good heat dissipation performance, the safety of use is obviously improved, and the service life is significantly prolonged. It will be understood by those skilled in the art that the inverter has all the features and advantages of the inverter housing described above, and details are not described herein again.

According to an embodiment of the present application, in addition to the inverter housing described above, the inverter further includes necessary structures and components that the conventional inverter has, such as an inverter bridge, control logic, and filter circuit, etc., I will not repeat them one by one.

In yet another aspect of the present application, the present application provides an automobile. According to an embodiment of the present application, the automobile includes the inverter described above. Therefore, the automobile inverter has better thermal conductivity and mechanical properties, and the safety is greatly improved. At the same time, the inverter housing is prepared from the magnesium alloy, which is beneficial to the weight reduction of the automobile and the user experience is better. Moreover, the vehicle has all the features and advantages of the inverter described above, and will not be further described herein.

According to the embodiment of the present application, in addition to the above-described inverter, the automobile has the necessary structures and components that the conventional automobile has, such as a vehicle body, an engine, a wheel, an interior, and the like, which will not be described in detail herein.

Example 1

Magnesium alloy formulation: 3.0 wt% Al, 0.25 wt% Mn, 1.55 wt% La, 3.0 wt% Ce, 0.13 wt% Nd, 0.6 wt% Zn, 0.15 wt% Ca, less than 0.1 wt% Sr, less than 0.1% by weight of Cu, and the balance of magnesium

Preparation steps: the pure magnesium ingot and the pure aluminum ingot are smelted in a melting furnace, the melting temperature is 700-750 ° C; the Mg-Ca, Mg-Mn, Mg-Zn intermediate alloy is added to the melting furnace to completely melt and smelt Temperature 700-750 ° C; adding Mg-La, Mg-Ce, Mg-Nd master alloy to the melting furnace, melting temperature 700-750 ° C, while adding the surface of the cover melt; 15% of the melt with RJ-5 flux Minute refining treatment, refining temperature 730 ° C - 760 ° C, and then standing for 80-120 minutes, temperature 650 ° C - 730 ° C, wherein Sr and Cu can be introduced through the impurities in the above raw materials, so do not need to be added separately.

Example 2

Magnesium alloy formulation: 2.0 wt% Al, 0.15 wt% Mn, 2.0 wt% La, 2.5% wt% Ce, 0.1 wt% Nd, 2.0 wt% Zn, 0.1 wt% Ca, less than 0.1 wt% Sr, less than 0.1% by weight of Cu, and the balance of magnesium.

Preparation steps: same as in Example 1.

Example 3

Magnesium alloy formulation: 4.0 wt% Al, 0.1 wt% Mn, 1.0 wt% La, 2.0 wt% Ce, 1.0 wt% Nd, 0.5 wt% Zn, 0.5 wt% Ca, less than 0.1 wt% Sr, less than 0.1% by weight of Cu, and the balance of magnesium.

Preparation steps: same as in Example 1.

Example 4

Magnesium alloy formulation: 2.5 wt% Al, 0.3 wt% Mn, 1.0 wt% La, 4.0 wt% Ce, 0.5 wt% Nd, 1.5 wt% Zn, 0.3 wt% Ca, less than 0.1 wt% Sr, less than 0.1% by weight of Cu, and the balance of magnesium.

Preparation steps: same as in Example 1.

Comparative example 1

Magnesium alloy formulation: 6 wt% Al, 0.4 wt% Mn, 0.48 wt% Zn, 1.2 wt% Ca, less than 0.1 wt% Sr, less than 0.1 wt% Cu, and the balance magnesium.

Preparation steps: same as in Example 1.

Comparative example 2

Magnesium alloy formulation: 6.0 wt% Al, 0.25 wt% Mn, 1.55 wt% La, 3.0 wt% Ce, 0.013 wt% Nd, 0.6 wt% Zn, 0.15 wt% Ca, less than 0.1 wt% Sr, less than 0.1% by weight of Cu, and the balance of magnesium.

Preparation steps: same as in Example 1.

Example 5

The magnesium alloys prepared in Examples 1-4 and Comparative Examples 1-2 were tested for mechanical properties and thermal conductivity, wherein:

(1) Thermal conductivity test: According to the test method of ASTM E 1461-07, the thermal conductivity of a magnesium alloy disc having a diameter of 12.7 mm and a thickness of 3 mm was tested by a laser flash method.

(2) Tensile performance test: According to the test method of ISO 6892-1, the smelted magnesium alloy melt is injected into the mold cavity by pressure casting equipment to obtain a tensile casting with a wall thickness of 3 mm. The test machine was subjected to a tensile test to obtain yield strength and elongation, wherein the yield strength was a yield limit at which 0.2% of residual deformation was produced, and the elongation was elongation at break.

The experimental results of Examples 1-4 and Comparative Examples 1-2 are shown in Table 1.

Table 1

	实施例1Example 1	实施例2Example 2	实施例3Example 3	实施例4Example 4	对比例1Comparative example 1	对比例2Comparative example 2
抗拉强度/MPaTensile strength / MPa	223223	222222	224224	223223	190190	230230
屈服强度/MPaYield strength / MPa	155155	153153	154154	152152	140140	160160
延伸率/％Elongation /%	55	55	55	55	33	44
导热系数/W/(m·K)Thermal conductivity / W / (m · K)	114114	112112	110110	113113	7070	7575

It can be seen from the data in Table 1 that the mechanical properties of the magnesium alloy obtained in Examples 1-4 of the present application are substantially the same as those of Comparative Examples 1-2, but the thermal conductivity is significantly improved, indicating that the magnesium alloy of the present application is guaranteed to meet the requirements of the mechanics. Excellent thermal conductivity under the premise of performance.

The magnesium alloy prepared in Example 1 and the AZ91D magnesium alloy were subjected to mechanical property test and material forming fluidity test, wherein the mechanical property test standard was ISO 6892-1, and the sample for measuring the fluidity of the material was measured by a mosquito mold and atmosphere. Die-casting molding, mold temperature 200 ° C, die-casting temperature 700 ° C, injection speed 3 laps, the starting point of the second speed is 140 mm, record the length of the injection mosquito mold, for analogy material flow. The results are shown in Tables 2 and 3, respectively.

Table 2

table 3

It can be seen from the data of Tables 2 and 3 that the high thermal conductivity magnesium alloy of the present application has a very high thermal conductivity and heat dissipation capability, and has high tensile strength, yield strength and elongation, and has higher tensile strength and elongation than AZ91D magnesium alloy. Very good formability and recycling capacity.

In the description of the present specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like means a specific feature described in connection with the embodiment or example. A structure, material or feature is included in at least one embodiment or example of the application. In the present specification, the schematic representation of the above terms is not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, various embodiments or examples described in the specification, as well as features of various embodiments or examples, may be combined and combined.

While the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are illustrative and are not to be construed as limiting the scope of the present application. The embodiments are subject to variations, modifications, substitutions and variations.

Claims

A high thermal conductivity magnesium alloy, wherein the high thermal conductivity magnesium alloy comprises: 2.0 to 4.0% by weight of Al, 0.1 to 0.3% by weight of Mn, and 1.0 to 2.0% by weight, based on the total mass of the high thermal conductivity magnesium alloy. La, 2.0 to 4.0% by weight of Ce, 0.1 to 1.0% by weight of Nd, 0.5 to 2.0% by weight of Zn, 0.1 to 0.5% by weight of Ca, less than 0.1% by weight of Sr, less than 0.1% by weight of Cu, and The amount of magnesium.
The high thermal conductivity magnesium alloy according to claim 1, wherein the high thermal conductive magnesium alloy comprises: 0.15 to 0.3% by weight of Mn, and 2.5 to 4.0% by weight of Ce based on the total mass of the high thermal conductivity magnesium alloy.
The high thermal conductivity magnesium alloy according to claim 1 or 2, wherein, based on the total mass of the high thermal conductivity magnesium alloy, the high thermal conductivity magnesium alloy comprises:

3.0 wt% Al, 0.25 wt% Mn, 1.55 wt% La, 3.0 wt% Ce, 0.13 wt% Nd, 0.6 wt% Zn, 0.15 wt% Ca, less than 0.1 wt% Sr, less than 0.1% by weight of Cu, and the balance of magnesium.
The high thermal conductivity magnesium alloy according to claim 1 or 2, wherein, based on the total mass of the high thermal conductivity magnesium alloy, the high thermal conductivity magnesium alloy comprises:

2.0% by weight of Al, 0.15% by weight of Mn, 2.0% by weight of La, 2.5% by weight of Ce, 0.1% by weight of Nd, 2.0% by weight of Zn, 0.1% by weight of Ca, less than 0.1% by weight of Sr, less than 0.1% by weight of Cu, and the balance of magnesium.
The high thermal conductivity magnesium alloy according to claim 1 or 2, wherein, based on the total mass of the high thermal conductivity magnesium alloy, the high thermal conductivity magnesium alloy comprises:

4.0% by weight of Al, 0.1% by weight of Mn, 1.0% by weight of La, 2.0% by weight of Ce, 1.0% by weight of Nd, 0.5% by weight of Zn, 0.5% by weight of Ca, less than 0.1% by weight of Sr, less than 0.1% by weight of Cu, and the balance of magnesium.
The high thermal conductivity magnesium alloy according to claim 1 or 2, wherein, based on the total mass of the high thermal conductivity magnesium alloy, the high thermal conductivity magnesium alloy comprises:

2.5 wt% Al, 0.3 wt% Mn, 1.0 wt% La, 4.0 wt% Ce, 0.5 wt% Nd, 1.5 wt% Zn, 0.3 wt% Ca, less than 0.1 wt% Sr, less than 0.1% by weight of Cu, and the balance of magnesium.
The high thermal conductivity magnesium alloy according to any one of claims 1 to 6, wherein the thermal conductivity is greater than 110 w/m.k.
The high thermal conductivity magnesium alloy according to any one of claims 1 to 7, wherein at least one of the following conditions is satisfied:

Tensile strength is greater than 220MPa;

Yield strength greater than 150MPa;

The elongation is greater than 4%.
An inverter housing, characterized in that at least a part of the inverter housing is formed by the high thermal conductivity magnesium alloy according to any one of claims 1-8.
An inverter comprising the inverter housing of claim 9.
A vehicle characterized by comprising the inverter of claim 10.