Nanometer TiB2 reinforced and brazed high-thermal-conductivity cast rare earth aluminum alloy as well as preparation method and application of nanometer TiB2 reinforced and brazed high-thermal-conductivity cast rare earth aluminum alloy

Abstract

The invention provides a nano TiB2 enhanced and brazed high-thermal-conductivity cast rare earth aluminum alloy as well as a preparation method and application thereof. The content of Ce in the nano TiB2 enhanced and brazed high-thermal-conductivity cast rare earth aluminum alloy is 5.0 wt.%-7.0 wt.%, and the content of Ti in the nano TiB2 enhanced and brazed high-thermal-conductivity cast rare earth aluminum alloy is 5.0 wt.%-7.0 wt.%. The content of Ni is 0.01 wt.%-1.2 wt.%; the content of Fe is 0.20 wt.% to 0.50 wt.%; the content of the TiB2 is 0.01 wt.% to 0.8 wt.%; the content of a single impurity element is less than or equal to 0.05 wt.%, the content of total impurities is less than or equal to 0.15 wt.%, and the balance is Al and inevitable impurities. The alloy has high thermal conductivity and high melting point, can meet the high thermal conductivity requirement and vacuum brazing requirement of aluminum alloy required in the heat dissipation field, and has very good application prospects and large-scale popularization potential in the heat dissipation field of communication base stations and the like.

Description

Technical Field

[0001] The present invention relates to aluminum alloy technology, in particular to a nano-TiB 2 Reinforced, brazable, high thermal conductivity cast rare earth aluminum alloy, preparation method and use thereof. Background Art

[0002] Thermally conductive aluminum alloys are widely used in the field of heat dissipation, including industries such as automobiles, air conditioners, and communication base stations. With their excellent thermal conductivity, lightweight characteristics, and corrosion resistance, they are ideal for various heat dissipation solutions. These materials can effectively transfer heat from the heat source to the heat dissipation device, thereby improving the stability and reliability of the equipment.

[0003] Brazing is an important welding process suitable for manufacturing complex liquid cooling systems. It uses a brazing material with a lower melting point than the base material and works at a temperature lower than the melting point of the base material and higher than the melting point of the brazing material to form a strong welding connection suitable for precision and complex components.

[0004] At present, liquid cooling plate base plates and large heat dissipation components are generally manufactured by machining and then connected to the cover plate by brazing. This processing method is complicated and costly. With the advancement of vacuum die-casting technology, it is possible to replace traditional processing methods with vacuum die-casting. However, due to the high silicon content, the melting temperature of traditional die-casting aluminum alloys is lower than 590°C, which cannot meet the needs of brazing (generally between 595-620°C). Therefore, the market urgently needs to develop new high thermal conductivity aluminum alloys that can meet the brazing requirements and have good casting and mechanical properties. Summary of the invention

[0005] The purpose of the present invention is to solve the problem that the existing cast aluminum alloy has low thermal conductivity and low melting point, and to propose a nano-TiB 2 The enhanced, brazable, high thermal conductivity cast rare earth aluminum alloy has a thermal conductivity and melting point of 200W / (m·K)-208W / (m·K) and 625℃~630℃ respectively, which can meet the high thermal conductivity and vacuum brazing requirements of aluminum alloys in the heat dissipation field. It has very good application prospects and potential for large-scale promotion in heat dissipation fields such as communication base stations.

[0006] It should be noted that, in the present invention, unless otherwise specified, the specific meaning of "including" in relation to composition limitations and descriptions includes both open-ended "including", "comprising", etc. and similar meanings, as well as closed-ended "composed of", "composed of", etc. and similar meanings.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is: a nano-TiB 2Enhanced, brazable, high thermal conductivity cast rare earth aluminum alloy, wherein the content of the element Ce is 5.0wt.%-7.0wt.%; the content of the element Ni is 0.01wt.%-1.2wt.%; the content of the element Fe is 0.20wt.%-0.50wt.%; TiB 2 The content is 0.01wt.%-0.8wt.%; the content of a single impurity element is ≤0.05wt.%, the content of total impurities is ≤0.15wt.%, and the balance is Al and unavoidable impurities.

[0008] Furthermore, the nano-TiB 2 The enhanced, brazable, high thermal conductivity cast rare earth aluminum alloy contains 5.5wt.%-6.5wt.% of Ce, 0.25wt.%-0.40wt.% of Fe, 0.8wt.%-1.0wt.% of Ni, and 0.5wt.%-1.0wt.% of TiB. 2 The content is 0.01wt.%-0.5wt.%.

[0009] Furthermore, the nano-TiB 2 The enhanced, brazable, high thermal conductivity cast rare earth aluminum alloy contains 5.8wt.% Ce, 0.40wt.% Fe, 1.0wt.% Ni, and 1.0wt.% TiB. 2 The content is 0.5wt.%.

[0010] Furthermore, the TiB 2 It exists in the form of hard ceramic particles with an average size of 200nm to 230nm and a Ti:B ratio of 2.1.

[0011] Furthermore, the nano-TiB 2 In the reinforced, brazable, high thermal conductivity cast rare earth aluminum alloy, the Ni addition amount is ≤1.2wt.%; the eutectic phase is refined, Al 11 Ce 3 Phase changes into fine fibers.

[0012] Furthermore, the nano-TiB 2 The enhanced, brazable, high thermal conductivity cast rare earth aluminum alloy has a strength of 128MPa to 145MPa, a thermal conductivity of 200W / (m·K) to 208W / (m·K), and a melting point of 625°C to 630°C.

[0013] Another object of the present invention is to disclose a nano-TiB 2 A method for preparing a reinforced, brazable, high thermal conductivity cast rare earth aluminum alloy comprises the following steps:

[0014] Step 1. Raw material preparation;

[0015] Step 2. Preheating: Place the metal mold in a 240-270℃ constant temperature box for preheating;

[0016] Step 3: Melting: pure Al, Al-Ce master alloy, Al-Ni master alloy and Al-Fe master alloy are placed in a crucible and heated to 790°C-820°C in a pit-type melting resistance furnace. After they are completely melted, they are kept warm for 30-40 minutes. Auxiliary processes are used to make the melt uniform. After the temperature drops to 720-750°C, Al-TiB is added. 2 The precursor is stirred rapidly, allowed to stand for 5-10 minutes, and high-purity argon gas is introduced at 720-740°C to degas the melt for 5-10 minutes to obtain a melt;

[0017] Step 4: Casting: pour the melt into a preheated metal mold at a temperature of 700°C-730°C to obtain nano-TiB 2 Strengthened, brazable, high thermal conductivity cast rare earth aluminum alloy.

[0018] Furthermore, the Ce content in the Al-Ce master alloy is 19 wt.% to 21 wt.%, preferably Al-20Ce master alloy, that is, the Ce content is 20 wt.%.

[0019] Furthermore, the Al-Ni master alloy has a Ni content of 9 wt.% to 11 wt.%, preferably an Al-10Ni master alloy, that is, a Ni content of 10 wt.%.

[0020] Furthermore, the Fe content in the Al-Fe master alloy is 9wt.% to 11wt.%, preferably an Al-10Fe master alloy, that is, the Fe content is 10wt.%.

[0021] Furthermore, the Al-TiB 2 TiB in the precursor 2 The content is 5.5wt.% to 6.5wt.%, preferably Al-6TiB 2 Base material, i.e. TiB 2 The content is 6wt.%.

[0022] Furthermore, the Al-6wt.%TiB 2 In the precursor, the molar ratio of titanium (Ti) to boron (B) is 2.1.

[0023] Furthermore, the crucible is a graphite clay crucible.

[0024] Furthermore, the auxiliary process is ultrasonic treatment.

[0025] Furthermore, the auxiliary process treatment time is 3min-5min.

[0026] Another object of the present invention is to disclose a nano-TiB 2 The invention discloses a reinforced, brazable, high thermal conductivity cast rare earth aluminum alloy for use in the field of radiators or in the field of component brazing assembly.

[0027] Nano TiB 2 The enhanced, brazable, high thermal conductivity cast rare earth aluminum alloy, its preparation method and use have the following advantages compared with the prior art:

[0028] 1) The alloy system of the present invention adopts a lower rare earth content (Ce: 5-7wt.%) and a lower Ni addition amount (≤1.2wt.%), which reduces the alloy cost on the one hand and ensures good castability of the alloy on the other hand.

[0029] 2) The elements (Ce, Ni, Fe) used in the present invention have very low solid solubility in Al, so that the alloy has excellent thermal conductivity, with a thermal conductivity coefficient of up to 203W / (m·K) and excellent thermal stability.

[0030] 3) The present invention obtains a fine eutectic structure through organizational regulation, improves the plasticity of the alloy, and is conducive to plastic processing; at the same time, the alloying degree is low, the melting point of the alloy is not greatly damaged, and the melting point of the alloy is above 625°C, which can well meet the brazing needs.

[0031] 4) The present invention adds a trace amount of nano-TiB to the alloy 2 Particles are beneficial to improving the comprehensive properties of the alloy.

[0032] The rare earth aluminum alloy of the present invention has both high thermal conductivity and high melting point, which can meet the high thermal conductivity requirements of aluminum alloys in the heat dissipation field, and at the same time, ensures vacuum brazing properties, and can realize the brazing assembly of heat dissipation components. 2 The reinforced, brazable, high thermal conductivity cast rare earth aluminum alloy has good application prospects and large-scale promotion potential in the field of radiators or component brazing assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 SEM image of the alloy prepared in Example 1. DETAILED DESCRIPTION

[0034] The present invention is further described below with reference to the examples. The description of the technical features described below is based on representative embodiments and specific examples of the present invention, but the present invention is not limited to these embodiments and specific examples. It should be noted that:

[0035] Unless otherwise stated, the units used in this specification are all international standard units, and the numerical values ​​and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0036] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints numerical values ​​A and B.

[0037] In the present specification, a numerical range expressed using "above" or "below" means a numerical range including the number.

[0038] In this specification, the word "may" means both performing a certain process and not performing a certain process.

[0039] In this specification, the use of "optional" or "optional" indicates that certain substances, components, execution steps, application conditions and other factors are used or not used.

[0040] In this specification, when "normal temperature" or "room temperature" is used, the temperature may be 15-25°C.

[0041] In this manual, the reagents or instruments used without indicating the manufacturer are all conventional products that can be obtained through commercial purchase.

[0042] Comparative Example 1-2

[0043] Comparative Examples 1-2 (Alloy 1-Alloy 2) disclose two aluminum alloys, which are prepared by the following method:

[0044] Step 1. Raw material preparation;

[0045] Step 2. Preheating: Place the metal mold in a 250°C constant temperature box for preheating;

[0046] Step 3. Melting: According to the nominal design composition in Table 1, weighed pure aluminum, Al-20Ce master alloy, Al-10Ni master alloy, and Al-10Fe master alloy are placed in a crucible, melted and heated to 790° C. in a pit-type melting resistance furnace, waited for complete melting, and kept warm for 40 minutes. An auxiliary process is used to make the melt uniform. At 720° C., high-purity argon gas is introduced to degas the melt for 5 minutes to obtain a melt;

[0047] Step 4. Casting: pour the melt into a preheated metal mold at a pouring temperature of 720° C. to obtain an aluminum alloy ingot. The compositions of the aluminum alloys prepared in Comparative Example 1 and Comparative Example 2 are shown in Table 1.

[0048] Example 1

[0049] This embodiment 1 (Alloy 3) discloses a nano-TiB 2A reinforced, brazable, high thermal conductivity cast rare earth aluminum alloy prepared by the following method:

[0050] Step 1. Raw material preparation;

[0051] Step 2. Preheating: Place the metal mold in a 250°C constant temperature box for preheating;

[0052] Step 3. Melting: According to the nominal design composition in Table 1, weighed pure aluminum, Al-20Ce master alloy, Al-10Ni master alloy, and Al-10Fe master alloy are placed in a crucible, melted and heated to 790°C in a pit-type melting resistance furnace, waited for complete melting, kept still for 40 minutes, used auxiliary processes to make the melt uniform, waited for the temperature to drop to 750°C, and added the pre-prepared Al-6wt.%TiB 2 The base material is stirred rapidly, and then allowed to stand for 5 minutes. High-purity argon gas is introduced at 720°C to degas the melt for 5 minutes to obtain a melt;

[0053] Step 4. Casting: pour the melt into a preheated metal mold at a pouring temperature of 720°C to obtain nano-TiB 2 Enhanced, brazable, high thermal conductivity cast rare earth aluminum alloy ingot. The composition of the aluminum alloy prepared in this example is shown in Table 1.

[0054] Table 1. Measured composition (wt.%) of each alloy of Comparative Examples 1-2 and Example 1

[0055] Alloy Ce Fe Ni <![CDATA[TiB 2 ]]> Al Comparative Example 1 1(Al-6Ce-0.4Fe) 5.85 0.41 0.01 0 Bal. Comparative Example 2 2(Al-6Ce-0.4Fe-1.0Ni) 6.12 0.39 0.98 0 Bal. Example 3 <![CDATA[3(Al-6Ce-0.4Fe-1.0Ni-0.5TiB 2 )]]> 6.08 0.40 1.08 0.49 Bal.

[0056] Note: TiB 2 The content is determined based on the measured amount of Ti and B. In the comparative example, the content of Ti and B is very low and basically the same. Therefore, the content of TiB in the comparative example is 2 The actual detection amount is 0.

[0057] The nano-TiB in Example 1 2 The thermal conductivity, mechanical properties and melting point values ​​of the enhanced, brazable, high thermal conductivity cast rare earth aluminum alloy and the comparative example 1-2 aluminum alloy were tested. The test results are as follows:

[0058] Table 2. Thermal conductivity, mechanical properties and melting point values ​​of the alloys in Comparative Examples 1-2 and Example 1

[0059] Alloy1 Alloy2 Alloy3 tensile strength 113MPa 128MPa 143MPa Yield Strength 49MPa 63MPa 72MPa Elongation 23MPa 21MPa 24MPa Melting point 637℃ 631℃ 630.2℃ Thermal conductivity 208W / (m·K) 203W / (m·K) 200W / (m·K)

[0060] From Table 2, it can be seen that with proper Ni alloying, the strength of the alloy increases from 113MPa to 128MPa, the plasticity decreases slightly, and the thermal conductivity of the alloy decreases from 208W / (m·K) to 203W / (m·K); while the proper addition of trace amounts of nano-TiB 2After the particles are formed, the comprehensive mechanical properties of the alloy are greatly improved, and the thermal conductivity is basically at 203W / (m·K); in addition, the melting point of the alloy is above 625℃, which meets the current brazing temperature requirements.

[0061] Figure 1 The nano-TiB prepared in Example 1 2 Electron microscope image of the enhanced, brazable, high thermal conductivity cast rare earth aluminum alloy. From the image, it can be seen that the eutectic phase in the eutectic region is very fine and dispersed in the matrix.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A nano-TiB2-enhanced, brazable, high thermal conductivity cast rare earth aluminum alloy, characterized in that: in, The content of element Ce is 5.0wt.%-7.0wt.%; the content of element Ni is 0.01wt.%-1.2wt.%; the content of element Fe is 0.20wt.%-0.50wt.%; the content of TiB2 is 0.01wt.%-0.8wt.%; the content of a single impurity element is ≤0.05wt.%, the content of total impurities is ≤0.15wt.%, and the balance is Al and unavoidable impurities.

2. The nano-TiB2-enhanced, brazable, high thermal conductivity cast rare earth aluminum alloy according to claim 1, characterized in that: The TiB2 exists in the form of hard ceramic particles with an average size of 200nm to 230nm, and Ti:B is 2.

1.

3. The nano-TiB2-enhanced, brazable, high thermal conductivity cast rare earth aluminum alloy according to claim 1, characterized in that: Its strength is 128MPa~145MPa, thermal conductivity is 200W / (m·K)-208W / (m·K), and melting point is 625℃~630℃.

4. A method for preparing the nano-TiB2-enhanced, brazable, high thermal conductivity cast rare earth aluminum alloy according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step 1. Raw material preparation; Step 2. Preheating: Place the metal mold in a 240-270℃ constant temperature box for preheating; Step 3. Melting: pure Al, Al-Ce master alloy, Al-Ni master alloy and Al-Fe master alloy are placed in a crucible together, heated to 790°C-820°C in a pit-type melting resistance furnace for melting, and kept warm for 30-40 minutes until completely melted, using an auxiliary process to make the melt uniform, waiting for the temperature to drop to 720°C-750°C, adding Al-TiB2 precursor, stirring rapidly, standing for 5min-10min, and passing high-purity argon gas at 720°C-740°C to degas the melt for 5min-10min to obtain a melt; Step 4. Casting: pouring the melt into a preheated metal mold at a pouring temperature of 700°C-730°C to obtain a nano-TiB2-reinforced, brazable, high thermal conductivity cast rare earth aluminum alloy.

5. The method for preparing the nano-TiB2-enhanced, brazable, high thermal conductivity cast rare earth aluminum alloy according to claim 4, characterized in that: The Ce content in the Al-Ce master alloy is 19wt.% to 21wt.%; And / or, the Ni content in the Al-Ni master alloy is 9wt.% to 11wt.%; And / or, the Fe content in the Al-Fe master alloy is 9wt.% to 11wt.%; And / or, the TiB2 content in the Al-TiB2 precursor is 5.5wt.% to 6.5wt.%.

6. The method for preparing the nano-TiB2-enhanced, brazable, high thermal conductivity cast rare earth aluminum alloy according to claim 4, characterized in that: In the Al-TiB2 precursor, the molar ratio of titanium to boron is 2.

1.

7. The method for preparing the nano-TiB2-enhanced, brazable, high thermal conductivity cast rare earth aluminum alloy according to claim 4, characterized in that: The crucible is a graphite clay crucible.

8. The method for preparing the nano-TiB2-enhanced, brazable, high thermal conductivity cast rare earth aluminum alloy according to claim 4, characterized in that: The auxiliary process is ultrasonic treatment.

9. The method for preparing the nano-TiB2-enhanced, brazable, high thermal conductivity cast rare earth aluminum alloy according to claim 4 or 8, characterized in that: The auxiliary process treatment time is 3min-5min.

10. Use of the nano-TiB2 reinforced, brazable, high thermal conductivity cast rare earth aluminum alloy according to any one of claims 1 to 4 in the field of radiators or parts brazing assembly.

Images