WO2017133415A1

WO2017133415A1 - Aluminum alloy die casting with high thermal conductivity and preparation method thereof

Info

Publication number: WO2017133415A1
Application number: PCT/CN2017/070957
Authority: WO
Inventors: 刘金
Original assignee: 中兴通讯股份有限公司
Priority date: 2016-02-02
Filing date: 2017-01-12
Publication date: 2017-08-10
Also published as: CN107022698A

Abstract

An aluminum alloy die casting with high thermal conductivity, comprising aluminum, silicon, iron, nickel, magnesium, and strontium. Weight percentages of each of the components are: 0.05% to 1.0% silicon, 0.3% to 1.3% iron, 0.2% to 2.0% nickel, 0.1% to 1.2% magnesium, 0.001% to 0.15% strontium, and the remainder of aluminum and unavoidable impurities. The weight percentage of the impurities is less than 0.2%. The aluminum alloy is formed by smelting followed by die casting.

Description

High thermal conductivity die-casting aluminum alloy and preparation method thereof

Technical field

The present disclosure belongs to the technical field of metal materials, for example, to a high thermal conductivity die-casting aluminum alloy and a preparation method thereof.

Background technique

With the development of modern industry, the heat dissipation of equipment in the electronics, communications, aerospace and automotive industries is increasing, and the requirements for the thermal conductivity of materials are becoming higher and higher. The performance of traditional metal materials can no longer meet the application needs. The development of high thermal conductivity aluminum alloy materials suitable for die casting has important application value. The aluminum-silicon alloy and the aluminum-magnesium alloy have excellent casting properties. However, the thermal conductivity is generally not high. The thermal conductivity of the mainstream die-cast aluminum alloy such as ADC (Aluminum-Alloy Die Castings) 12 can reach (96-110) W / (m · K), ADC1 (LM6 (UK) A material in the BS 1490 standard)) is a die-cast aluminum alloy with a castability deviation, and its thermal conductivity is about 142 W/(m·K), which is already a material with a relatively high thermal conductivity in die-cast aluminum alloy. Although the thermal conductivity of pure aluminum is as high as 230 W/(m·K), the mechanical properties are poor and the casting performance is poor, which makes it difficult to meet the heat dissipation requirements of high heat-consuming devices in the electronics and communication industries.

In recent years, in order to obtain a high thermal conductivity aluminum alloy suitable for die casting, a large number of studies have been carried out at home and abroad. The patent application of CN201310444626 discloses a silicon content of 5% to 7.5% and is refined by boron, titanium and zirconium. The aluminum-silicon alloy of the cast structure has a thermal conductivity of (153-160) W/(m·K) in the as-cast state. Even if the structure is refined by the modifier, the thermal conductivity of the as-cast material is still low, and most complex large-scale die-casting parts cannot be heated to improve the thermal conductivity. NIKKEI MC ALUMINIUM developed Al-2Ni-Fe die-cast aluminum alloy, which has a thermal conductivity of 190 W/(m·K) in the as-cast state, but the casting performance is reduced by more than 35% compared with ADC12, and its hardness is low and its strength is low. This material is mainly used for heat sinks and flat heat conduction parts.

Summary of the invention

The present disclosure provides a high thermal conductivity die-casting aluminum alloy and a method of manufacturing the same, and the high thermal conductivity die-casting aluminum alloy of the present disclosure has both good casting performance and high thermal conductivity.

The present disclosure provides a high thermal conductivity die-casting aluminum alloy, including aluminum, silicon, iron, nickel, magnesium and bismuth, each component occupies a mass percentage of: 0.05-1.0% of silicon, 0.3-1.3% of iron, and 0.2 of nickel. -2.0%, magnesium 0.1-1.2%, 锶0.001-0.15%, the balance being aluminum and unavoidable impurities; wherein the mass percentage of the impurity content is less than 0.2%.

Optionally, the impurity contains copper, manganese, and chromium; wherein, the mass percentage of the copper is less than 0.1%, the mass percentage of the manganese is less than 0.1%, and the mass percentage of the chromium is less than 0.06%.

The present disclosure also provides a method for preparing a high thermal conductivity die-cast aluminum alloy, comprising:

Aluminum, silicon, iron, nickel, magnesium, strontium are obtained by sequentially melting aluminum and magnesium, aluminum-silicon intermediate alloy, aluminum-iron intermediate alloy, aluminum-nickel intermediate alloy aluminum, and aluminum-bismuth intermediate alloy at different heating temperatures. Melt

Refining the aluminum, silicon, iron, nickel, magnesium, and lanthanum melt to obtain a refined product;

Removing the solvent and scum from the surface of the refining product, and performing static treatment on the refining product to remove slag to obtain an aluminum alloy solution;

The temperature of the aluminum alloy solution is adjusted to 680-720 ° C to perform casting.

Optionally, the step of melting the aluminum and magnesium, the aluminum-silicon intermediate alloy, the aluminum-iron intermediate alloy, the aluminum-nickel intermediate alloy aluminum, and the aluminum-bismuth intermediate alloy in sequence at different heating temperatures comprises:

Heating the smelting vessel, when the heating temperature reaches the first heating temperature, adding aluminum and magnesium, and melting to obtain a first melt;

When the heating temperature is raised to the second heating temperature, an aluminum-silicon intermediate alloy, an aluminum-iron intermediate alloy, and an aluminum-nickel intermediate alloy are added to the melting vessel to be melted, so that the aluminum-silicon intermediate alloy, the aluminum-iron intermediate alloy, An aluminum-nickel intermediate alloy is fused with the first melt to obtain a second melt;

After the aluminum-silicon intermediate alloy, the aluminum-iron intermediate alloy, and the aluminum-nickel intermediate chemicalization, the heating temperature is lowered to a third temperature, and an aluminum-niobium intermediate alloy is added to the melting vessel to be melted, thereby The second melt is fused together to obtain aluminum, silicon, iron, nickel, magnesium, and lanthanum melt.

Optionally, the first heating temperature is 300 °C.

Optionally, the second heating temperature is 780 °C.

Optionally, the third heating temperature is 580-700 °C.

Heating the crucible, and when the crucible temperature reaches 300 ° C, aluminum and magnesium are sequentially added thereto. Melt to obtain the first melt;

When the enthalpy temperature reaches 780 ° C, an aluminum-silicon intermediate alloy, an aluminum-iron intermediate alloy and an aluminum-nickel intermediate alloy are added to the first melting, so that the enthalpy temperature is maintained at 580-850 ° C to cause the first melting The objects are fused together to obtain a second melt;

After the aluminum-silicon intermediate alloy, the aluminum-iron intermediate alloy, and the aluminum-nickel alloy are chemically consolidated, the heating temperature is adjusted to 580-700 ° C, and the aluminum-niobium intermediate alloy is added to the melting vessel to be melted to be combined with the first The two melts are fused together to obtain aluminum, silicon, iron, nickel, magnesium, and lanthanum.

Optionally, the refining treatment of the aluminum, silicon, iron, nickel, magnesium, and lanthanum melts to obtain the refined products includes:

An aluminum alloy refining agent is added to the aluminum, silicon, iron, nickel, magnesium, and lanthanum melt, and refined at a temperature of 580-700 ° C for 8-20 min.

An inert gas is introduced into the aluminum, silicon, iron, nickel, magnesium, and cerium melt, and is subjected to refining treatment by a bubble filtration method.

The present disclosure adds four elements of silicon, nickel, iron and magnesium into the aluminum alloy, and nickel has little effect on the thermal conductivity of the aluminum alloy, forming an Al-Ni compound in the alloy, which acts as a dispersion strengthening effect while utilizing the Ni-rich phase. The spherical shape and small size of the particles make it improve the strength of the aluminum alloy while maintaining the high elongation of the material; silicon strengthens the aluminum alloy and also contributes to the fluidity of the alloy, but the addition of silicon is reduced. The thermal conductivity of the alloy; iron has the function of promoting the demolding of the part, but the excessive iron content will form a coarse needle-like compound phase, which will reduce the mechanical properties of the alloy, and iron will reduce the thermal conductivity of the alloy; magnesium has a strengthening effect and can be used in the alloy. The Mg-Al, Mg-Ni compound is formed with aluminum and nickel, but the solid solution of the magnesium into the aluminum matrix causes the thermal conductivity of the alloy to be lowered. The combination of these four elements has little effect on the thermal conductivity of the aluminum alloy, and improves the casting properties and mechanical properties of the alloy, so that the high thermal conductivity die-casting aluminum alloy has both high thermal conductivity and good casting performance and mechanical properties.

Since the elemental silicon in the material is little or substantially absent, the anodized film caused by the insolubilization of silicon in the oxidation process and the dissolution of other alloying elements in the solution are prevented from being uneven and incomplete. Thereby, the appearance of the anodized film is uniform in color.

At the same time, by adding yttrium as a modifier, it is possible to carry out the same when the α-Al solid solution and the needle-like Si are the same. The refinement reduces the resistance of the electron movement in the alloy, thereby improving the thermal conductivity of the material, and the grain refinement also improves the mechanical properties of the material.

The high thermal conductivity aluminum alloy of the present disclosure has good flow performance and can be used for a thin-walled shell with a complicated die-casting structure. The die-casting part made of a high thermal conductivity aluminum alloy has a thermal conductivity of up to 212.2 W/(mK) under normal temperature conditions, and the tensile strength is high. Not less than 96.8 MPa. At the same time, anodization can be performed to achieve a uniform color appearance.

DRAWINGS

Figure 1 is a comparison of the fluidity of the aluminum alloy prepared in Examples 1-3 with the ADC 12.

detailed description

The present disclosure will be described below by way of specific embodiments. The embodiments of the present disclosure and the features in the embodiments may be arbitrarily combined with each other without conflict.

Example 1

In step 110, the ingredients are weighed according to a total weight of 8 kg, and a 6.84 Kg aluminum block, a 0.04 Kg magnesium block, a 0.4 Kg aluminum silicon alloy AlSi20, a 0.48 Kg aluminum iron alloy AlFe10, a 0.4 Kg aluminum nickel alloy AlNi10, and a 0.08 Kg aluminum bismuth alloy AlSr10 are prepared. .

In step 120, preheating enthalpy, when the temperature reaches 300 ° C or more, sequentially adding aluminum block and magnesium block to melt, and when the temperature rises above 780 ° C, adding aluminum silicon alloy, aluminum iron alloy, aluminum nickel alloy, keeping the temperature at Within 680 ~ 850 °C, after the material is melted, adjust the solution temperature to 680 ~ 700 °C, add Al-10Sr master alloy, and refine with aluminum alloy refining agent for 15min. After refining, remove the solvent and scum from the liquid surface. Allow to stand for 10 min to make the inclusions fully float or sink, and slag.

In step 130, after adjusting the solution to 680-720 ° C, the aluminum alloy melt is poured into a high-pressure die casting machine for die-casting production.

Example 2

In step 210, the ingredients are weighed according to a total weight of 8 kg, and 5.864 Kg of aluminum block, 0.096 Kg of magnesium block, 0.2 Kg of aluminum-silicon alloy AlSi20, 0.24 Kg of aluminum-iron alloy AlFe10, 1.6 Kg of aluminum-nickel alloy AlNi10, and 0.048 Kg of aluminum-bismuth alloy AlSr10 are prepared. .

In step 220, preheating 坩埚, when the temperature reaches 300 ° C or more, sequentially adding aluminum block and magnesium block to melt, and when the temperature rises above 780 ° C, adding aluminum silicon alloy, aluminum iron alloy, aluminum nickel alloy, and ensuring Hold the temperature within 680 ~ 850 ° C, after the material is melted, adjust the solution temperature to 680 ~ 700 ° C, then add Al-10Sr intermediate alloy, refined with aluminum alloy refining agent for 12min. After refining, remove the solvent and scum from the liquid surface. Allow to stand for 8 min to make the inclusions fully float or sink, and slag.

In step 230, after adjusting the solution to 680-720 ° C, the aluminum alloy melt is poured into a high-pressure die casting machine for die-casting production.

Example 3

In step 310, the ingredients are weighed according to a total weight of 8 kg, and prepare 6.312 Kg aluminum block, 0.064 Kg magnesium block, 0.12 Kg aluminum silicon alloy AlSi20, 0.64 Kg aluminum iron alloy AlFe10, 0.8 Kg aluminum nickel alloy AlNi10, and 0.064 Kg aluminum bismuth alloy AlSr10. .

In step 320, preheating 坩埚, when the temperature reaches 300 ° C or more, sequentially adding aluminum block and magnesium block to melt, when the temperature rises above 780 ° C, adding aluminum silicon alloy, aluminum iron alloy, aluminum nickel alloy, keeping the temperature at Within 680 ~ 850 °C, after the material is melted, adjust the solution temperature to 680 ~ 700 °C, add Al-10Sr master alloy, and refine with aluminum alloy refining agent for 20min. After refining, remove the solvent and scum from the liquid surface. Allow to stand for 15 min to make the inclusions fully float or sink, and slag.

In step 330, after adjusting the solution to 680-700 ° C, the aluminum alloy melt is poured into a high-pressure die casting machine for die-casting production.

The properties of the parts made of the high thermal conductivity aluminum alloy prepared in the examples were tested below.

Table 1 Table 1-3 Preparation of high thermal conductivity aluminum alloy composition table

To examine the thermal conductivity of the aluminum alloy prepared in the examples, the diameters of the parts of Examples 1-3 were cut according to the standard method of testing the thermal conductivity of materials by American Society for Testing and Materials (ASTM) E1461. The 12.7mm thick 2mm disc is used for the thermal conductivity test. The test specimens are all as-cast specimens. The experimental equipment is the German NETZSCH laser thermal conductivity tester. At the same time, according to the national standard GB/T 228, the bulk sample plate samples are used for mechanical performance test, and the test samples are all tested. For the as-cast sample, the test equipment is a tensile tester. The test data is as shown in Table 2 below:

Table 2 Performance Table of High Thermal Conductivity Aluminum Alloy Prepared in Examples 1-3

组别Group	抗拉强度tensile strength	断后延伸率Post-break elongation	导热系数Thermal Conductivity
实施例1Example 1	96.8MPa96.8MPa	3.7％3.7%	198.3W/(m.K)198.3W/(m.K)
实施例2Example 2	115.2MPa115.2MPa	4.5％4.5%	202.5W/(m.K)202.5W/(m.K)
实施例3Example 3	106.3MPa106.3MPa	5.2％5.2%	212.2W/(m.K)212.2W/(m.K)

In order to test the casting properties of the material, the flow length of the above material and the ADC 12 were compared by a spiral casting mold, and the results of the test data are shown in Fig. 1. The ordinate in Fig. 1 indicates the aluminum alloy of each of the examples. The ratio of the flow length to the flow length of the ADC 12.

Industrial applicability

In the high thermal conductivity die-casting aluminum alloy provided by the present disclosure and the preparation method thereof, the high thermal conductivity die-casting aluminum alloy has both good casting performance and high thermal conductivity.

Claims

A high thermal conductivity die-casting aluminum alloy, including aluminum, silicon, iron, nickel, magnesium and strontium, the mass percentage of each component is: 0.05-1.0% of silicon, 0.3-1.3% of iron, 0.2-2.0% of nickel Magnesium 0.1-1.2%, 锶0.001-0.15%, the balance being aluminum and unavoidable impurities; wherein the mass percentage of the impurity content is less than 0.2%.
The high thermal conductivity die-cast aluminum alloy according to claim 1, wherein said impurities contain copper, manganese and chromium; wherein said copper has a mass percentage of less than 0.1%, said manganese has a mass percentage of less than 0.1%, said chromium The mass percentage is less than 0.06%.
A method for preparing a high thermal conductivity die-casting aluminum alloy, comprising:

Aluminum, silicon, iron, nickel, magnesium, strontium are obtained by sequentially melting aluminum and magnesium, aluminum-silicon intermediate alloy, aluminum-iron intermediate alloy, aluminum-nickel intermediate alloy aluminum, and aluminum-bismuth intermediate alloy at different heating temperatures. Melt

Refining the aluminum, silicon, iron, nickel, magnesium, and lanthanum melt to obtain a refined product;

Removing the solvent and scum from the surface of the refining product, and performing static treatment on the refining product to remove slag to obtain an aluminum alloy solution;

The temperature of the aluminum alloy solution is adjusted to 680-720 ° C to perform casting.
The method according to claim 3, wherein said aluminum and magnesium, an aluminum-silicon intermediate alloy, an aluminum-iron intermediate alloy, an aluminum-nickel intermediate alloy aluminum, and an aluminum-bismuth intermediate alloy are sequentially melted at different heating temperatures. Processing includes:

Heating the smelting vessel, when the heating temperature reaches the first heating temperature, adding aluminum and magnesium, and melting to obtain a first melt;

When the heating temperature is raised to the second heating temperature, an aluminum-silicon intermediate alloy, an aluminum-iron intermediate alloy, and an aluminum-nickel intermediate alloy are added to the melting vessel to be melted, so that the aluminum-silicon intermediate alloy, the aluminum-iron intermediate alloy, An aluminum-nickel intermediate alloy is fused with the first melt to obtain a second melt;

After the aluminum-silicon intermediate alloy, the aluminum-iron intermediate alloy, and the aluminum-nickel intermediate chemicalization, the heating temperature is lowered to a third temperature, and an aluminum-niobium intermediate alloy is added to the melting vessel to be melted, thereby The second melt is fused together to obtain aluminum, silicon, iron, nickel, magnesium, and lanthanum melt.
The method of claim 4 wherein said first heating temperature is 300 °C.
The method of claim 4 wherein said second heating temperature is 780 °C.
The method of claim 4 wherein said third heating temperature is between 580 and 700 °C.
The method according to claim 3, wherein said aluminum and magnesium, an aluminum-silicon intermediate alloy, an aluminum-iron intermediate alloy, an aluminum-nickel intermediate alloy aluminum, and an aluminum-bismuth intermediate alloy are sequentially melted at different heating temperatures. Processing includes:

Heating the crucible, when the crucible temperature reaches 300 ° C, sequentially adding aluminum and magnesium thereto, and melting to obtain a first melt;

When the enthalpy temperature reaches 780 ° C, an aluminum-silicon intermediate alloy, an aluminum-iron intermediate alloy and an aluminum-nickel intermediate alloy are added to the first melting, so that the enthalpy temperature is maintained at 580-850 ° C to cause the first melting The objects are fused together to obtain a second melt;

After the aluminum-silicon intermediate alloy, the aluminum-iron intermediate alloy, and the aluminum-nickel alloy are chemically consolidated, the heating temperature is adjusted to 580-700 ° C, and the aluminum-niobium intermediate alloy is added to the melting vessel to be melted to be combined with the first The two melts are fused together to obtain aluminum, silicon, iron, nickel, magnesium, and lanthanum.
The method according to claim 3, wherein said refining treatment of said aluminum, silicon, iron, nickel, magnesium, lanthanum melt to obtain a refined product comprises:

An aluminum alloy refining agent is added to the aluminum, silicon, iron, nickel, magnesium, and lanthanum melt, and refined at a temperature of 580-700 ° C for 8-20 min.
The method according to claim 3, wherein said refining treatment of said aluminum, silicon, iron, nickel, magnesium, lanthanum melt to obtain a refined product comprises:

Introducing an inert gas into the molten aluminum, silicon, iron, nickel, magnesium, and cerium, using bubble filtration It is refined.