Radiator, preparation method thereof and radiating system

Abstract

The invention discloses a radiator, a preparation method thereof and a radiating system, and belongs to the technical field of radiating. The radiator is made of monotectic alloy materials. The monotectic alloy material contains a first metal and a second metal. The radiator comprises a first layer and a second layer in the thickness direction, the mass ratio of the first metal in the first layer is higher than that of the first metal in the second layer, the mass ratio of the second metal in the first layer is lower than that of the second metal in the second layer, and the melting point of the first metal is higher than that of the second metal. When the radiator is used for radiating heat of a heat source, the second layer is in direct contact with the heat source to be radiated, and thermal interface materials such as silicone grease do not need to be filled between the radiator and the heat source. When the heat source works to generate heat, the second layer is heated to be softened and even partially melted, so that the second layer can be in full contact with the heat source, the thermal resistance of a contact interface of the radiator and the heat source is reduced, and the radiating effect is improved.

Description

Technical Field

[0001] The present application relates to the field of heat dissipation technology, and in particular to a heat sink and a preparation method thereof and a heat dissipation system. Background Art

[0002] Heat dissipation is an important issue in the development of modern electronic devices and energy because it directly affects the performance and life of the device.

[0003] At present, the heat dissipation of heat sources is mainly achieved through the combination of heat sinks and thermal interface materials. A heat sink is a device that can quickly dissipate heat to the surrounding environment, while a thermal interface material is a material that can fill the gap between the heat source and the heat sink, reduce thermal resistance, and improve heat transfer efficiency. Although thermal interface materials (TIM) can effectively improve the heat transfer effect between the heat source and the heat sink, the addition of TIM materials will make the heat dissipation structure complicated and bring some inconveniences. For example, the number of interfaces increases, the stress increases, and the installation and maintenance requirements of TIM materials are high. Summary of the invention

[0004] Based on the above-mentioned deficiencies, the present application provides a radiator and a preparation method thereof and a heat dissipation system to improve the problems of poor heat dissipation effect, complex structure, and high installation and maintenance requirements of the radiator in the related art.

[0005] This application is implemented as follows:

[0006] In a first aspect, an example of the present application provides a heat sink, the material of the heat sink is a monotectic alloy material. The monotectic alloy material contains a first metal and a second metal. The heat sink includes a first layer and a second layer in a thickness direction, the mass proportion of the first metal in the first layer is higher than the mass proportion of the first metal in the second layer, the mass proportion of the second metal in the first layer is lower than the mass proportion of the second metal in the second layer, and the melting point of the first metal is higher than the melting point of the second metal. The second layer is used to contact with a heat source to be dissipated.

[0007] In the above implementation process, when it is necessary to use the heat sink made of the above-mentioned eutectic alloy material to dissipate heat from the heat source, the second layer in the thickness direction of the heat sink can be brought into contact with the heat source to absorb the heat from the heat source, and transfer the heat to the first layer in the thickness direction, and quickly dissipate the heat from the first layer to the surrounding environment or other cold sources, so as to achieve heat dissipation of the heat source. Usually, when a solid heat sink contacts a solid heat source, there will be a certain gap between the contact interfaces. If the gap between the contact interfaces is large, it will affect the heat transfer efficiency of the heat source to the heat sink, thereby reducing the heat dissipation effect. However, in the heat sink provided by the example of the present application, since the first metal and the second metal in the eutectic alloy material tend to the first layer and the second layer in the thickness direction respectively, and the first layer and the second layer are integrally formed, when the second layer contacts the heat source, the second layer contains more low-melting-point second metal material, which will partially melt when absorbing heat, causing the second layer to soften or slightly melt, so that the second layer can fully contact the surface of the heat source, reducing the thermal resistance of the contact interface. And because the first layer of the heat sink is basically formed by the second metal, the structure of the heat sink can be kept stable when the low-melting-point metal of the second layer melts, reducing the probability of metal liquid leakage, allowing the heat sink to stably dissipate heat from the heat source and improving the heat dissipation effect.

[0008] By using the heat sink provided in the example of the present application to dissipate heat from a heat source, there is no need to fill other thermal interface materials between the heat sink and the heat source, which can simplify the heat dissipation structure and its installation and maintenance operations, reduce thermal stress during the heat dissipation process, and improve the stability of the heat dissipation structure and the heat dissipation effect.

[0009] In combination with the first aspect, in an optional embodiment of the present application, the melting point of the second metal is 60-600°C.

[0010] Optionally, the melting point of the second metal is 100-400°C.

[0011] Optionally, the melting point of the second metal is 150-300°C.

[0012] In the above implementation process, a heat sink is prepared using a eutectic alloy material containing a second metal with a melting point of 60 to 600°C. After the second layer of the heat sink is brought into contact with the surface of a heat source, the second layer contains a larger amount of second metal material with a low melting point. The second metal material will melt when heated, causing the second layer to soften or slightly melt. Therefore, the second layer can fully contact the surface of the heat source, thereby reducing the thermal resistance of the contact interface and improving the heat dissipation effect of the heat sink.

[0013] In combination with the first aspect, in an optional embodiment of the present application, the melting point of the first metal is not less than 650°C.

[0014] Optionally, the melting point of the first metal is 650-1200°C

[0015] In the above implementation process, a heat sink is prepared using a eutectic alloy material containing a first metal with a melting point of not less than 650°C. During the heat dissipation process of the heat sink, the first metal that tends to be located in the first layer can maintain a stable solid phase, which can reduce the probability of leakage of the second metal with a lower melting point, improve the structural stability of the heat sink, and stably dissipate the heat transferred to the first layer to the surrounding environment or other cold sources, thereby achieving heat dissipation of the heat source.

[0016] In combination with the first aspect, in an optional embodiment of the present application, the thermal conductivity of the first metal and the second metal is not less than 10 W / (m·K).

[0017] Optionally, the thermal conductivity of the first metal and the second metal is not less than 50 W / (m·K).

[0018] In the above implementation process, a heat-conductive monotectic alloy material is prepared using a metal with a thermal conductivity of not less than 10 W / (m·K), so that the monotectic alloy material has good thermal conductivity, can quickly absorb the heat generated by the heat source and dissipate the heat to the surrounding environment or other cold sources, thereby achieving heat dissipation of the heat source.

[0019] In combination with the first aspect, in an optional embodiment of the present application, the density of the first metal is less than the density of the second metal.

[0020] Optionally, the density of the first metal is 2 to 9 g / cm 3 .

[0021] Optionally, the density of the second metal is 7 to 10 g / cm 3 .

[0022] In the above implementation process, a second metal with a lower melting point and a higher density and a first metal with a higher melting point and a lower density are used to prepare a eutectic alloy material, so that the first metal tends to form on the top layer of the thermally conductive eutectic alloy material, and the second metal tends to form on the bottom layer of the thermally conductive eutectic alloy material, forming a thermally conductive eutectic alloy material with an upper and lower layered structure. The bottom layer can be directly contacted with the heat source. When the heat source generates heat, the low melting point metal in the bottom layer will partially melt, so that the second layer of the heat sink can soften or even slightly melt, and can more fully contact the surface of the heat source, thereby reducing the thermal resistance of the contact interface and improving the heat dissipation effect.

[0023] In combination with the first aspect, in an optional embodiment of the present application, the first metal includes at least one of Al or Cu. And / or, the second metal includes at least one of Sn, Bi or In.

[0024] In the above implementation process, when a first metal such as Al or Cu with good thermal conductivity, low density and high melting point is smelted with a second metal such as Sn, Bi or In with good thermal conductivity, high density and low melting point to prepare a eutectic alloy material, the melt will undergo liquid-liquid phase separation. The melt containing more first metal materials with high melting point and low density will float to the upper layer of the melt, and the melt containing more second metal materials with low melting point and high density will sink to the bottom layer of the melt. In the subsequent solidification process, as the temperature decreases, the melt containing more first metal materials with high melting point and low density will form a first layer of solid phase in the upper layer of the melt, and the melt containing more second metal materials with low melting point and high density will gradually form a second layer of solid phase below the above-mentioned first layer of solid phase, thereby obtaining a thermally conductive eutectic alloy material with layered distribution of low melting point metals and high melting point metals.

[0025] In combination with the first aspect, in an optional embodiment of the present application, the eutectic alloy material is a Cu-Sn-Bi ternary alloy or an Al-In binary alloy.

[0026] In combination with the first aspect, in an optional embodiment of the present application, in the monotectic alloy material, the mass content of the first metal is 45-90%.

[0027] In the above implementation process, the mass proportion of the first metal in the eutectic alloy material is 45-90%. During the heat conduction process, it can not only reduce the thermal resistance of the thermal interface, but also improve the structural stability of the heat conductor, and can stably dissipate the heat transferred to the first layer to the surrounding environment or other cold sources, thereby realizing the heat dissipation of the heat source.

[0028] In a second aspect, an example of the present application provides a method for preparing a heat sink, comprising:

[0029] The first metal and the second metal are melted to form a uniform first liquid phase; under a vacuum or inert gas environment, the first liquid phase is poured into a mold forming a heat sink, and the cooling rate is controlled not to exceed 15°C / min to form a heat sink.

[0030] Optionally, the cooling rate is controlled not to exceed 10°C / min.

[0031] Optionally, natural cooling is performed.

[0032] In the above implementation process, when preparing the heat sink, the first metal and the second metal are melted to obtain a uniformly mixed first liquid phase, and then the first liquid phase is poured into a mold, and the first liquid phase is slowly cooled to form a layered eutectic alloy material heat sink. When the heat sink is used to dissipate heat from a heat source, the second layer mainly formed by the second metal will soften or slightly melt, and can fully contact the surface of the heat source, reducing the thermal resistance of the contact interface, and the first layer mainly formed by the first metal can maintain a stable solid phase structure, and can stably dissipate heat to the surrounding environment or other cold sources, thereby improving the heat dissipation efficiency of the heat source.

[0033] In a third aspect, an example of the present application provides a heat dissipation system, comprising a heat source and the heat sink provided in the first aspect. The second layer of the heat sink contacts the heat source.

[0034] Optionally, the heat source comprises a chip.

[0035] In the above implementation process, in the heat dissipation system, the second layer of the heat sink provided by the first aspect is brought into contact with the surface of a heat source such as a chip. When the heat source such as the chip generates heat, the eutectic alloy material forming the heat sink can absorb the heat. Since the metal forming the second layer is mainly a second metal with a lower melting point, the second layer will soften or even partially melt, and then will fully contact the surface of the heat source such as the chip, thereby reducing the thermal resistance between the contact interfaces. The heat from the heat source such as the chip can be more efficiently transferred to the first layer mainly formed by the first metal with a high melting point. The first layer can maintain a stable structure during the heat dissipation process, which can reduce the probability of leakage of the low-melting-point metal at the first layer, thereby improving the stability of the heat sink, and can stably and quickly dissipate heat to the surrounding environment or other cold sources, thereby improving the heat dissipation efficiency of the heat source. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0037] Figure 1 A schematic diagram of the structure of the heat dissipation system provided for the example of this application;

[0038] Figure 2 Schematic diagram of the phase diagram of the monotectic alloy material provided as an example of this application;

[0039] Figure 3 for Figure 2 The state diagram of the first temperature;

[0040] Figure 4 for Figure 2 Schematic diagram of the state of the second temperature;

[0041] Figure 5 for Figure 2 Schematic diagram of the state of the third temperature;

[0042] Figure 6 for Figure 2 Schematic diagram of the state of the fourth temperature;

[0043] Figure 7 The metallographic phase diagram of the Cu-Sn-Bi eutectic ternary alloy material provided in Example 1 of the present application;

[0044] Figure 8 for Figure 7 A partial enlarged view of the first layer;

[0045] Fig. 9 for Figure 7 A partial enlarged view of the second layer;

[0046] Fig.10 for Fig. 9 A partial magnified image of the Bi-Sn eutectic;

[0047] Fig.11 This is an optical picture of the heat sink of Example 1 taken out after heat dissipation is completed;

[0048] Fig.12 This is an optical picture of the heat sink of the control group taken out after the heat dissipation was completed.

[0049] Icon: 1- cooling system; 100- radiator; 101- first layer; 102- second layer; 200- heat source; L- first liquid phase; L1- second liquid phase; L2- third liquid phase; α- high temperature solid phase; β- low temperature solid phase. DETAILED DESCRIPTION

[0050] The embodiments of the present application will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. In the examples, if specific conditions are not specified, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0051] Heat dissipation is an important issue in the development of modern electronic devices and energy sources, as it directly affects the performance and life of the device.

[0052] At present, the heat dissipation of heat source is mainly achieved through the combination of heat sink and thermal interface material. Heat sink is a device that can quickly dissipate heat to the surrounding environment, while thermal interface material is a material that can fill the gap between heat source and heat sink, reduce thermal resistance and improve heat transfer efficiency.

[0053] For example, when dissipating heat from a heat source such as a chip, the conventional heat dissipation method is to fit the heat sink to the surface of the chip, and then fill the space between the heat sink and the chip with thermal interface materials (TIM) such as thermal grease. The heat sink is usually a copper plate or an alloy plate with high thermal conductivity. Thermal interface materials such as thermal grease are usually fluid or viscous pastes that can fill the tiny gap between the copper plate and the chip surface, improving the heat transfer efficiency between the heat source and the heat sink.

[0054] Although thermal interface materials can effectively improve the heat transfer efficiency between the heat source and the heat sink, the increase of thermal interface materials will make the entire heat dissipation structure complicated and bring some inconvenience. For example, filling thermal interface materials between the heat sink and the heat source will lead to an increase in interfaces and greater thermal stress, which will easily lead to lower bonding strength between the thermal interface material and the heat source and between the thermal interface material and the heat sink, and worse stability of the entire heat dissipation structure, resulting in poor heat dissipation stability. For another example, filling thermal interface materials between the heat sink and the heat source will make the installation process of the entire heat dissipation structure more complicated, more difficult to operate, and increase maintenance requirements.

[0055] Therefore, the present application further improves the radiator, thereby improving the heat dissipation efficiency of the radiator to a certain extent and simplifying the installation and maintenance costs of the radiator. In order to make the purpose, technical solution and advantages of the embodiment of the present application clearer, the technical solution in the embodiment of the present application will be clearly and completely described below in conjunction with the drawings in the embodiment of the present application.

[0056] See also Figure 1 The present application example provides a heat dissipation system 1, including a heat sink 100 and a heat source 200.

[0057] Please continue to read Figure 1 , the heat sink 100 has a first layer 101 and a second layer 102 along the thickness direction. The material of the heat sink 100 is a monotectic alloy material. The monotectic alloy material contains a first metal and a second metal, and the melting point of the first metal is higher than the melting point of the second metal. The mass proportion of the first metal in the first layer 101 is higher than the mass proportion of the first metal in the second layer 102, and the mass proportion of the second metal in the first layer 101 is lower than the mass proportion of the second metal in the second layer 102.

[0058] In the heat dissipation system 1 , the second layer 102 containing more second metal contacts the surface of the heat source 200 .

[0059] During operation of the heat dissipation system 1 , the heat source 200 generates heat, which can be transferred to the radiator 100 through the second layer 102 in direct contact with the heat source 200 , and dissipated to the surrounding environment or other cold sources by the first layer 101 of the radiator 100 , thereby achieving heat dissipation of the heat source 200 .

[0060] Among them, during the heat dissipation process, when the heat of the heat source 200 is transferred to the second layer 102, the temperature of the second layer 102 rises. Since the second layer 102 contains a large amount of second metal with a low melting point, the second layer 102 will soften or even partially melt, and can make more sufficient contact with the surface of the heat source 200, thereby reducing the thermal resistance of the contact interface between the second layer 102 and the heat source 200, thereby improving the heat dissipation efficiency of the radiator 100.

[0061] Furthermore, since the first layer 101 of the radiator 100 contains a large amount of the first metal with a high melting point, the first layer 101 can maintain a stable structure during the heat dissipation process, which can reduce the probability of leakage of the molten metal in the second layer 102, and can more stably and quickly dissipate heat to the surrounding environment or other cold sources, thereby achieving heat dissipation of the heat source 200.

[0062] By utilizing the above-mentioned radiator 100 to dissipate heat from the heat source 200, the second layer 102 of the radiator 100 can be in direct contact with the surface of the heat source 200, and there is no need to fill additional thermal interface material between the second layer 102 of the radiator 100 and the heat source 200. There are fewer thermal interfaces between the radiator 100 and the heat source 200, and the thermal stress is lower, which can improve the heat dissipation stability and heat dissipation efficiency of the heat dissipation system 1 and simplify the installation and maintenance costs of the heat dissipation system 1.

[0063] In addition, in a conventional heat dissipation system, the thermal interface material is filled between the heat sink 100 and the heat source 200, which results in a low bonding strength between the thermal interface material and the heat sink, and between the thermal interface material and the heat source 200. In the present application, the first layer 101 and the second layer 102 in the heat sink 100 are integrally formed, and are multilayer alloy materials formed by a eutectic reaction of a high-temperature melt during cooling, and the bonding strength between the layers is high. That is, the material of the heat sink 100 is a eutectic alloy material formed by a first metal and a second metal.

[0064] Furthermore, the embodiment of the present application also provides a method for preparing a heat sink. The heat sink 100 provided by the example of the present application is further described in detail below in conjunction with the preparation method.

[0065] The preparation method of the radiator comprises:

[0066] S1. Melting the first metal and the second metal to form a uniform first liquid phase.

[0067] S2. In a vacuum or inert gas environment, pour the first liquid phase into a mold for forming a heat sink, control the cooling rate to not exceed 15°C / min, and form a heat sink.

[0068] The first metal and the second metal are heated to above their melting temperatures for smelting to form a uniformly mixed first liquid phase, and then the first liquid phase is poured into a mold. During the slow solidification process, the first liquid phase gradually transforms into a solid phase and a second liquid phase of another component. As the solidification temperature continues to decrease, the second liquid phase gradually solidifies to form another solid phase, forming a two-phase separated monotectic alloy material.

[0069] When monotectic alloy solidifies, liquid phase separation occurs, and the liquid phase is transformed into a solid phase and a liquid phase of another component. This reaction is called monotectic reaction. In this application, "monotectic alloy" is a layered material with solid-solid phase separation formed by monotectic reaction.

[0070] For example, see Figure 2 and Figure 3 When the temperature is raised to the first temperature of T1, the first metal and the second metal form a uniformly mixed first liquid phase L. When the temperature is lowered to the second temperature between T1 and T2, see Figure 2 and Figure 4 , the first liquid phase L will undergo liquid phase separation, separating into the second liquid phase L1 and the third liquid phase L2. The second liquid phase L1 and the third liquid phase L2 are immiscible and insoluble. For example, the second liquid phase L1 has a low density and floats; the third liquid phase L2 has a low density and sinks. When the temperature is reduced to the third temperature between T2 and T3, see Figure 2 and Figure 5 , a high-temperature solid phase α and a third liquid phase L2 will be formed. The high-temperature solid phase α floats up, and the low-temperature third liquid phase L2 sinks. When the temperature drops to the fourth temperature below T3, please refer to Figure 6 , a stratified eutectic alloy material of high-temperature solid phase α and low-temperature solid phase β will be formed.

[0071] In some embodiments, the melting point of the second metal is 60-600°C, and the melting point of the first metal is not less than 650°C.

[0072] The melting point of the second metal is 60-600°C, and when the temperature of the heat source rises, the second layer 102 can be softened or partially melted in time to reduce the thermal resistance of the contact interface, so as to dissipate the heat from the heat source in time. The melting point of the first metal is not less than 650°C, and it can remain stable during the heat dissipation process to continuously and stably dissipate heat to the surrounding environment.

[0073] Illustratively, the melting point of the second metal may be one of 60°C, 70°C, 80°C, 90°C, 100°C, 150°C, 200°C, 250°C, 300°C, 350°C, 400°C, 450°C, 500°C, 550°C or 600°C, or a range between any two thereof.

[0074] Furthermore, in some embodiments, the melting point of the second metal may be 100-400°C.

[0075] Furthermore, in some embodiments, the melting point of the second metal may be 150-300°C.

[0076] In some embodiments, the melting point of the first metal may be 650-1200°C.

[0077] Illustratively, the melting point of the first metal may be one of 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, 950°C, 1000°C, 1050°C, 1100°C, 1150°C, or 1200°C, or a range between any two thereof.

[0078] The density of the first metal is less than that of the second metal. When preparing the eutectic alloy material, as the temperature decreases, the uniform first liquid phase will undergo liquid phase separation to form two difficult to mix and dissolve liquid phases. There is a certain density difference between the two liquid phases. The lighter liquid phase containing a large amount of the first metal will float, and the heavier liquid phase containing a large amount of the second metal will sink.

[0079] In some embodiments, the density of the first metal may be 2 to 9 g / cm 3 .

[0080] For example, the density of the first metal may be 2 g / cm 3 , 2.7g / cm 3 , 3g / cm 3 , 5g / cm 3 、7.14g / cm 3 、8.9g / cm 3 or 9g / cm 3 One of them or a range between any two.

[0081] In some embodiments, the density of the second metal may be 7 to 10 g / cm 3 .

[0082] For example, the density of the second metal may be 7 g / cm 3 , 7.1g / cm 3 , 7.2g / cm 3 , 7.3g / cm 3 , 8g / cm 3 , 8.5g / cm 3 , 9g / cm 3 or 10g / cm 3 One of them or a range between any two.

[0083] In some possible embodiments, thermal conductivity of the first metal and the second metal is not less than 10 W / (m·K).

[0084] Using metals with high thermal conductivity to prepare monotectic alloy materials can improve the thermal conductivity of the monotectic alloy materials and improve the heat dissipation efficiency of the heat sink.

[0085] Exemplarily, the thermal conductivity of the first metal and the second metal can be one of 10 W / (m·K), 20 W / (m·K), 30 W / (m·K), 40 W / (m·K), 50 W / (m·K), 60 W / (m·K), 70 W / (m·K), 80 W / (m·K), 90 W / (m·K), 100 W / (m·K), 110 W / (m·K), 120 W / (m·K) or 130 W / (m·K), or a range between any two of them.

[0086] Furthermore, in some possible embodiments, the thermal conductivity of the first metal and the second metal is not less than 50 W / (m·K).

[0087] Furthermore, in some embodiments, the thermal conductivity of the first metal and the second metal may be 50 to 600 W / (m·K).

[0088] In some embodiments, the first metal includes at least one of Al or Cu.

[0089] In some embodiments, the second metal includes at least one of Sn, Bi, or In.

[0090] Exemplarily, the first metal is selected from Cu, and the second metal is selected from Sn and Bi, and a heat sink made of a Cu—Sn—Bi alloy material can be prepared.

[0091] During the preparation process of the Cu-Sn-Bi alloy material, phase separation will occur, forming a solidification structure with distinct upper and lower stratifications. Among them, the upper layer is a Cu-rich high-temperature alloy region, and the lower layer is a Bi-rich low-temperature alloy region. That is, the first layer 101 is a Cu-rich upper layer, and the second layer 102 is a Bi-rich lower layer. The melting point of Cu is much higher than the melting point of Bi. When the Bi-rich second layer 102 is attached to the heat source 200, the second layer 102 is easily softened by heat and can fully contact the surface of the heat source 200, thereby reducing the thermal resistance of the contact interface and improving the heat dissipation efficiency of the radiator 100.

[0092] Exemplarily, the first metal is selected from Al, and the second metal is selected from In and Sn, and a heat sink made of an Al—In—Sn alloy material can be prepared.

[0093] Exemplarily, the first metal is selected from Al, and the second metal is selected from In, and a heat sink made of Al-In monotectic alloy material can be prepared.

[0094] Exemplarily, the first metal is selected from Al, and the second metal is selected from Bi, and a heat sink made of an Al-Bi monotectic alloy material can be prepared.

[0095] Furthermore, in some embodiments, the mass content of the first metal in the monotectic alloy material is 45% to 90%.

[0096] For example, the mass content of the first metal in the monotectic alloy material may be 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85% or 90% or any range between two of them.

[0097] Furthermore, in some embodiments, the mass content of the second metal in the monotectic alloy material may be 10% to 55%.

[0098] Exemplarily, the Cu—Sn—Bi monotectic alloy material contains 5% to 15% of Sn element, 5% to 50% of Bi element and 45% to 90% of Cu element.

[0099] The mass ratio of metal elements in different alloy systems is adjusted according to the corresponding alloy phase diagram so as to satisfy the composition range for the eutectic reaction to occur.

[0100] In step S2 , the shape of the cavity in the mold may be rectangular to prepare a heat sink 100 with a plate-like structure.

[0101] In step S2, the cooling speed is controlled not to exceed 15°C / min. The cooling speed is slow, and a clear layered structure can be formed.

[0102] Exemplarily, the cooling rate can be one of 1°C / min, 2°C / min, 3°C / min, 4°C / min, 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min, 10°C / min, 11°C / min, 12°C / min, 13°C / min, 14°C / min, 15°C / min, or a range between any two of them.

[0103] Furthermore, in some embodiments, the cooling rate is controlled not to exceed 10° C. / min.

[0104] Furthermore, in some embodiments, natural cooling may be performed.

[0105] In some embodiments, heat source 200 includes a chip.

[0106] The heat sink of the present application is further described in detail below in conjunction with the embodiments.

[0107] Example 1

[0108] Embodiment 1 provides a heat sink, and the preparation method thereof comprises:

[0109] Step 1: Raw material preparation: Select copper-based monotectic alloy material - Cu-Sn-Bi monotectic ternary alloy material as the heat sink material, and its raw materials include 48wt% Cu, 32wt% Sn and 20wt% Bi.

[0110] Step 2: Mix the above raw materials according to the proportion, heat to above 1100° C., melt for 30 minutes, and then stir evenly to obtain a uniform first liquid phase.

[0111] Step 3: Pour the first liquid phase into the mold and place it under vacuum at 10 -3 Pa environment at a cooling rate of 10°C / min to form a Cu-Sn-Bi eutectic ternary alloy casting.

[0112] Step 3: Cut, grind and polish the Cu-Sn-Bi monotectic ternary alloy casting to form a heat sink.

[0113] The metallographic structure of the Cu-Sn-Bi eutectic ternary alloy material provided in Example 1 is as follows: Figure 7 shown. Figure 8 for Figure 7 A partial enlarged view of the first layer. Fig. 9 for Figure 7 A partial enlarged view of the second layer. Fig.10 for Fig. 9 A partial enlarged view of the Bi-Sn eutectic. Figure 7 It can be seen that the Cu-Sn-Bi monotectic ternary alloy has a clear layered structure, with the upper layer being black and the lower layer being white. Figure 8 In the figure, the black matrix is ​​a Cu matrix, and a small amount of white Bi phase is dispersed in the Cu matrix. Fig. 9 In the figure, the white matrix is ​​Bi, which contains a large area of ​​gray-white Bi-Sn eutectic phase and a small amount of black Cu phase. For the morphology of the Bi-Sn eutectic phase, see Fig.10 .from Figure 8 and Fig. 9 It can be seen that the mass proportion of Cu in the first layer is much greater than that in the second layer, and the mass proportion of Bi in the first layer is much smaller than that in the second layer. The melting point of the first layer high temperature alloy area can reach above 900℃, and the thermal conductivity can reach above 300W / m·K. The phase transition temperature of the second layer low temperature eutectic structure can be lower than 150℃, about 138℃.

[0114] Example 2

[0115] Embodiment 2 provides a heat sink, which is different from Embodiment 1 in that the heat sink is made of Al-In-Sn ternary monotectic alloy material. The raw materials of the Al-In-Sn ternary monotectic alloy material include 70wt% Al, 10wt% Sn and 20wt% In.

[0116] Example 3

[0117] Embodiment 3 provides a heat sink, which is different from Embodiment 1 in that the heat sink is made of Al-In binary monotectic alloy material. The raw materials of the Al-In binary monotectic alloy material include 50 wt% Al and 50 wt% In.

[0118] Test Case

[0119] The heat sinks provided in Examples 1 to 3 were placed on heat sources with constant power, and the actual temperature of the heat source was detected at different heat source powers. The heat sink structure formed by the aluminum heat sink and the thermal interface material of 0.1 mm indium sheet was used as the control group, and the actual temperature of the heat source was detected at different heat source powers. The test results are shown in Table 1.

[0120] After the heat dissipation is completed, the heat sink of Example 1 and the heat sink of the control group are taken out. The picture of the heat sink after the heat sink of Example 1 is as follows: Fig.11 As shown, the picture of the radiator after the control group was taken out is as follows Fig.12 shown.

[0121] Table 1

[0122]

[0123] As can be seen from Table 1, under low power of the heat source, the heat dissipation efficiency of Example 1 is worse than that of the control group, but when the power of the heat source is high, the heat dissipation effect of the heat sink provided by the example of the present application on the heat source is better than that of the control group, and the actual temperature of the heat source can be effectively reduced. Under low power of the heat source, the heat dissipation effect of the heat sink provided by Examples 2 and 3 on the heat source is not much different from that of the control group, or even better. Under high power of the heat source, the heat dissipation effect of the heat sink provided by Examples 2 and 3 on the heat source is significantly better than that of the control group, and the actual temperature of the heat source can be effectively reduced.

[0124] like Fig.11 As shown, after taking out the heat sink provided in Example 1, the heat dissipation surface is relatively flat. Fig.12 As shown, after removing the radiator of the control group, it was found that the silicone grease was pumped out, which would easily dry out and fail in the long run.

[0125] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A radiator, characterized in that: The material of the heat sink is a monotectic alloy material; the monotectic alloy material contains a first metal and a second metal; the heat sink includes a first layer and a second layer in a thickness direction, the mass proportion of the first metal in the first layer is higher than the mass proportion of the first metal in the second layer, and the mass proportion of the second metal in the first layer is lower than the mass proportion of the second metal in the second layer; the melting point of the first metal is higher than the melting point of the second metal, and the second layer is used to contact a heat source to be dissipated.

2. The heat sink according to claim 1, characterized in that: The melting point of the second metal is 60 to 600°C; Optionally, the melting point of the second metal is 100 to 400° C.; Optionally, the melting point of the second metal is 150-300°C.

3. The radiator according to claim 1 or 2, characterized in that: The melting point of the first metal is not less than 650°C; Optionally, the melting point of the first metal is 650-1200°C.

4. The heat sink according to claim 1, characterized in that: The thermal conductivity of the first metal and the second metal is not less than 10 W / (m·K); Optionally, the thermal conductivity of the first metal and the second metal is not less than 50 W / (m·K).

5. The heat sink according to claim 1, characterized in that The density of the first metal is less than the density of the second metal; Optionally, the density of the first metal is 2 to 9 g / cm 3 ; Optionally, the density of the second metal is 7 to 10 g / cm 3 .

6. The heat sink according to claim 1, characterized in that The first metal includes at least one of Al or Cu; And / or, the second metal includes at least one of Sn, Bi or In.

7. The heat sink according to claim 1, characterized in that: The monotectic alloy material is a Cu-Sn-Bi ternary alloy or an Al-In binary alloy.

8. The heat sink according to claim 1, characterized in that In the monotectic alloy material, the mass content of the first metal is 45% to 90%.

9. A method for preparing a heat sink according to any one of claims 1 to 8, characterized in that: include: Melting the first metal and the second metal to form a uniform first liquid phase; In a vacuum or inert gas environment, pouring the first liquid phase into a mold for forming the heat sink, controlling the cooling rate to not exceed 15° C. / min, to form the heat sink; Optionally, the cooling rate is controlled not to exceed 10°C / min; Optionally, natural cooling is performed.

10. A heat dissipation system, characterized in that: comprising a heat source and the heat sink according to any one of claims 1 to 8; the second layer of the heat sink is in contact with the heat source; Optionally, the heat source includes a chip.

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