HEAT TRANSFER MEMBER

- Lemon Metal Inc.

There is provided a heat transfer member which is made of an aluminum alloy including silicon (Si), iron (Fe), and magnesium (Mg). The aluminum alloy further includes at least one or two or more of copper (Cu), manganese (Mn), zinc (Zn), titanium (Ti), calcium (Ca), tin (Sn), phosphorus (P), chromium (Cr), zirconium (Zr), nickel (Ni), strontium (Sr), and vanadium (V).

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Description
CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Korean Patent Application No. 10-2022-0130673 (filed on Oct. 12, 2022), which is hereby incorporated by reference in its entirety.

BACKGROUND

The present disclosure relates to a heat transfer member, and more particularly, to a heat transfer member used for cooling or heating products in mechanical parts, electrical and electronic products, and the like.

A heat transfer member is a part used to rapidly release heat from a product to the outside or quickly heat the product to a desired temperature.

A cooling fin is widely known as a representative example of the heat transfer member. The cooling fin refers to a part that is integrally or detachably coupled to a part that requires cooling or is easily overheated and lowers the temperature of the part by rapidly convecting heat.

The cooling fin is widely used in small electronic products such as computers and laptops, and appliances such as air conditioners and refrigerators, as well as heat sinks and automobile parts.

In recent years, the application of cooling fins is expanding as the thermal management of parts acts as an important issue even in the power semiconductor field and electric vehicle field.

A heat transfer member including the cooling fin must have high thermal conductivity for rapid cooling. In addition, since the heat transfer member is also a kind of part, it is necessary to secure a certain level of strength or higher. Furthermore, since the cooling fin is composed of a large number of fins and is generally mainly manufactured through a casting process, it must have excellent formability (especially castability) at the same time.

Aluminum alloys have been used as a material that can satisfy the required characteristics of the heat transfer member as described above.

In general, since aluminum is light and easy to cast, has a face centered cubic (FCC) crystal structure, and has high solubility, it is well alloyed with other metals, is easy to process at room temperature and high temperature, and has good electrical and thermal conductivity, so that it is widely used in industry. In particular, in recent years, aluminum alloys in which aluminum is mixed with other metals are widely used to improve fuel efficiency or reduce the weight of automobiles and electronic products.

The cooling fin usually has various shapes. In particular, in order to increase a contact area with a low-temperature medium (for example, air or a cooling fluid) outside the product, the cooling fin has various shapes.

For example, a straight fin is a cooling fin having a flat shape, and a pin fin is a cooling fin having a pin-shaped shape and, if necessary, a circular cross section. In addition, the shape of the fin may be a wave shape or a conical shape.

The cooling fin may consist of a large number of fins, regardless of the shape of the fins, while the shape is generally uncomplicated. Accordingly, when aluminum is used as a material for the cooling fin, a precision casting process such as die casting has recently been in the limelight and applied.

Meanwhile, die casting is a precision casting method that obtains the same casting as a mold by injecting molten metal into the mold that is precisely machined according to the required casting shape.

In particular, this die casting method has high mass productivity because the dimensions of the product to be produced are accurate, so that there is little need for a post-process such as finishing, mass production is possible, and the production cost is low. As a result, the die casting is expanding its application range to various fields such as automobile parts, electrical devices, optical devices, and measuring instruments.

However, in the die casting method, gas is incorporated into the molten metal during the process, and the incorporated gas may be present as defects such as voids in the final product. Accordingly, the die casting method may have a disadvantage in that the elongation is lowered.

Meanwhile, the conventional aluminum alloy shows a high degree of utilization, accounting for about 90% or more of the materials used in the die casting process. However, conventional aluminum alloys such as A383 are lagging behind the market demand for heat dissipation efficiency due to the recent miniaturization and integration of electronic components.

SUMMARY

The present disclosure has been devised to solve the problems of the related art as described above.

Specifically, the present disclosure is directed to providing a heat transfer member to which a new aluminum alloy having superior electrical conductivity, thermal conductivity, and formability, compared to conventional aluminum alloys, is applied by controlling a composition ratio of silicon, iron, and magnesium in an aluminum base.

Through this, the present disclosure is directed to providing a heat transfer member made of a new aluminum alloy that can be used for various parts requiring excellent heat transfer characteristics.

In addition, the present disclosure is directed to providing a heat transfer member that can suppress defects that may occur during casting and suppress the scattering of molten metal through an aluminum alloy capable of further improving thermal conduction and heat dissipation properties and further improving castability at the same time compared to conventional aluminum alloys by more precisely limiting a composition ratio of iron and magnesium and further including copper and manganese.

A heat transfer member according to one embodiment of the present disclosure is made of an aluminum alloy including 8.0 to 9.0 wt % of silicon (Si), 0.35 to 0.55 wt % of iron (Fe), and 0.02 to 0.3 wt % of magnesium (Mg), based on the total amount of the alloy.

An aluminum alloy applied to a heat transfer member according to another embodiment of the present disclosure essentially includes 8.0 to 9.0 wt % of silicon (Si); 0.35 to 0.55 wt % of iron (Fe); and 0.02 to 0.3 wt % of magnesium (Mg), and includes at least one or two or more of 0.001 to 0.2 wt % of copper (Cu); 0.001 to 0.2 wt % of manganese (Mn); 0.001 to 0.2 wt % of zinc (Zn); 0.001 to 0.2 wt % of titanium (Ti); 0.001 to 0.2 wt % of calcium (Ca); 0.001 to 0.2 wt % of tin (Sn); 0.001 to 0.2 wt % of phosphorus (P); 0.001 to 0.2 wt % of chromium (Cr); 0.001 to 0.2 wt % of zirconium (Zr); 0.001 to 0.2 wt % of nickel (Ni); 0.001 to 0.1 wt % of strontium (Sr); and 0.001 to 0.01 wt % of vanadium (V), based on the total amount of the alloy.

The aluminum alloy applied to a heat transfer member according to the present disclosure may have an electrical conductivity of 30 to 40% IACS and a thermal conductivity of 145 to 165 W/mK at a temperature of 25 to 200° C.

The member according to the present disclosure may include: a base plate; at least one or more fin-shaped or pin-shaped fins; and a connection portion connecting the base plate and the fin.

At this time, it is preferable that a curvature radius of the connection portion is 3 mm.

The heat transfer member according to the present disclosure may include various shapes of fins.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present disclosure will become more apparent to those of ordinary skill in the art by describing in detail exemplary embodiments thereof with reference to the accompanying drawings, in which:

FIG. 1 is a configuration diagram showing a measurement state of the thermal conduction performance of an aluminum alloy applied to a heat transfer member according to one embodiment of the present disclosure;

FIG. 2 is a graph showing the thermal conduction performance of the aluminum alloy applied to the heat transfer member according to one embodiment of the present disclosure;

FIG. 3 is a configuration diagram showing a measurement state of the heat dissipation performance of the aluminum alloy applied to the heat transfer member according to one embodiment of the present disclosure;

FIG. 4 is a graph showing the heat dissipation performance of the aluminum alloy applied to the heat transfer member according to one embodiment of the present disclosure;

FIG. 5 is a graph showing the results of measuring the thermal conductivity of aluminum alloys applied to a heat transfer member according to Examples of the present disclosure and aluminum alloys of Comparative Examples according to Table 2;

FIG. 6 is a graph showing the results of measuring the thermal conductivity of the aluminum alloys applied to a heat transfer member according to the Examples of the present disclosure and the aluminum alloys of the Comparative Examples according to Table 3;

FIG. 7 is a graph showing the results of measuring the thermal conductivity of the aluminum alloys applied to a heat transfer member according to the Examples of the present disclosure and the aluminum alloys of the Comparative Examples according to Table 4;

FIG. 8 shows die casting simulation conditions of a cooling fin that is one embodiment of the heat transfer member of the present disclosure; and

FIGS. 9 to 13 show simulation results of die casting characteristics according to the curvature value (R value) of a connection portion of the cooling fin, which is one embodiment of the heat transfer member of the present disclosure.

 DETAILED DESCRIPTION

Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

An aluminum alloys applied to a heat transfer member according to an embodiment of the present disclosure are an aluminum alloy for casting or die casting used for mechanical parts, or electrical and electronic products. For this purpose, the aluminum alloy applied to the heat transfer member according to the embodiment of the present disclosure is an aluminum alloy including aluminum (Al) as a base, essentially including as much silicon (Si), iron (Fe), and magnesium (Mg) as a controlled composition range, and furthermore, including at least one or two or more of copper (Cu), manganese (Mn), zinc (Zn), titanium (Ti), calcium (Ca), tin (Sn), phosphorus (P), chromium (Cr), zirconium (Zr), nickel (Ni), strontium (Sr), and vanadium (V) and some impurities.

Silicon (Si) is added to improve the fluidity and strength of the aluminum alloy.

In addition, when silicon (Si) is added to the aluminum alloy of the heat transfer member, the liquidus temperature of the aluminum alloy is reduced according to the addition of silicon (Si). As a result, as the solidification time of the aluminum alloy becomes longer, the castability of the aluminum alloy is improved.

In addition, the low solubility of silicon (Si) in the aluminum (Al) base causes precipitation of pure silicon (pure Si). The precipitated silicon (Si) can improve friction resistance, and improve the fluidity, castability, thermal conductivity, and tensile strength of the aluminum alloy.

The composition range of silicon (Si) added to the aluminum alloy applied to the heat transfer member of the present disclosure is preferably 8.0 to 9.0 wt % (or %).

When the composition range of silicon (Si) is less than 8.0 wt %, there is a problem in that it is difficult to realize the effect of improving fluidity and strength.

On the other hand, when the composition range of silicon (Si) is more than 9.0 wt %, since an Si intermetallic compound is formed according to a reaction with other additive elements to be described below along with needle-shaped or plate-shaped Si precipitation due to excessive silicon (Si) in the aluminum alloy of the present disclosure, there is a problem in that the elongation of the alloy is lowered and thermal conductivity is excessively reduced.

Since iron (Fe) is mostly precipitated as an intermetallic compound such as Al3Fe after casting in the aluminum alloy (primary precipitation), it is possible to increase the strength of the aluminum alloy due to the higher density of iron (Fe) compared to aluminum while minimizing the decrease in thermal conductivity of aluminum. At the same time, iron (Fe) can reduce mold sticking when forming an aluminum alloy product by die casting.

For this purpose, the composition range of iron (Fe) added to the aluminum alloy applied to the heat transfer member of the present disclosure is more preferably 0.35 to 0.55 wt % (or %).

When the composition range of iron (Fe) is less than 0.35 wt % or more than 0.55 wt %, the thermal conductivity of the aluminum alloy of the present disclosure may be lowered, voids may be generated in the casting, or strength improvement may be insufficient.

Furthermore, iron (Fe) can prevent the adhesion of the aluminum alloy applied to the heat transfer member of the present disclosure and improve strength.

For this purpose, the composition range of iron (Fe) added to the aluminum alloy applied to the heat transfer member of the present disclosure is more preferably 0.40 to 0.50 wt % (or %).

When the composition range of iron (Fe) is less than 0.4 wt %, there is a problem in that it is difficult to realize the effect of preventing the adhesion and improving strength.

On the other hand, when the composition range of iron (Fe) is more than 0.5 wt %, the corrosion resistance of the aluminum alloy is lowered due to the presence of excessive iron (Fe), and there is a problem in that precipitates are easily generated in the aluminum alloy.

In addition, iron (Fe) is effective in suppressing the coarsening of recrystallized grains in the aluminum alloy and refining grains during casting. However, when iron (Fe) is included in the aluminum alloy in an amount of 0.7 wt % or more, corrosion of the aluminum alloy may be caused.

Magnesium (Mg) improves the castability of the aluminum alloy, improves the mechanical properties of the alloy by solid solution hardening and precipitation hardening mechanisms, and further significantly affects the thermal conductivity of the alloy.

Specifically, magnesium (Mg) is may be combined with the silicon (Si) in the aluminum alloy and precipitated in the form of Mg2Si to affect mechanical properties, and the remaining silicon is precipitated alone in the form of silicon to improve mechanical properties and strength.

In addition, magnesium (Mg) serves to prevent internal corrosion of the alloy due to a passivation effect by rapidly growing a dense surface oxide layer (MgO) on the surface of the aluminum alloy.

Furthermore, magnesium (Mg) has the effect of improving machinability along with the weight reduction of the aluminum alloy.

Magnesium (Mg) is preferably included in an amount of 0.02 to 0.3 wt % based on the total weight of the aluminum alloy applied to the heat transfer member of the present disclosure.

When the composition range of magnesium (Mg) is less than 0.02 wt %, there is a problem in that it is difficult to realize the effects of adding magnesium.

On the other hand, when the composition range of magnesium (Mg) is more than 0.3 wt %, there is a problem in that the thermal conductivity is rather reduced, and the fluidity of the alloy is lowered, making it difficult to manufacture a product having a complex shape.

The aluminum alloy applied to the heat transfer member of the present disclosure may include at least one or two or more of the following alloy elements (including unavoidable impurities).

Copper (Cu), as a component included in a content of 0.001 to 0.2 wt % based on the total weight of the aluminum alloy of the present disclosure, affects the hardness, strength, and corrosion resistance of the aluminum alloy. Therefore, when the composition range of copper (Cu) is 0.001 to 0.2 wt %, it is possible to improve the strength without reducing the corrosion resistance of the aluminum alloy within the above range.

Copper (Cu) improves the strength of the aluminum alloy by a solid solution hardening mechanism. Copper (Cu) is preferably included within the range of 0.001 to 0.2 wt % based on the total weight of the aluminum alloy. When copper is added in an amount of less than 0.001 wt %, the effect of improving the strength is lowered. On the other hand, when the composition range of copper is more than 0.2 wt %, the corrosion resistance of the aluminum alloy is lowered.

In addition, copper (Cu) may improve the fluidity of the molten metal. However, when an excessive amount of copper is added to the aluminum alloy, the corrosion resistance of the aluminum alloy may be lowered and weldability may be lowered. Also, similar to iron (Fe) described above, when copper is included in aluminum in an amount of more than 0.2 wt %, copper may cause corrosion of the aluminum alloy.

Manganese (Mn) improves the corrosion resistance of the aluminum alloy, improves the tensile strength of the alloy through the solid solution hardening effect and the fine precipitate dispersion effect, and further may increase the softening resistance at high temperature and improve surface treatment properties.

Manganese (Mn) is preferably included within the range of 0.001 to 0.2 wt % based on the total weight of the aluminum alloy.

When the composition range of manganese (Mn) is less than 0.001 wt %, the effect of adding manganese cannot be achieved.

On the other hand, when the composition range of manganese (Mn) is more than 0.2 wt %, there is a problem in that castability is lowered.

Zinc (Zn) can improve the castability and electrochemical properties of the aluminum alloy, and can improve mechanical properties by solid solution hardening and precipitation hardening effects.

Zinc (Zn) is preferably included within the range of 0.001 to 0.2 wt % based on the total weight of the aluminum alloy.

When the composition range of zinc (Zn) is less than 0.001 wt %, the effect of adding zinc cannot be achieved.

On the other hand, when the composition range of zinc (Zn) is more than 0.2 wt %, there is a problem in that castability, weldability, and corrosion resistance are lowered.

Titanium (Ti) enables crystal grain refinement of the aluminum alloy by precipitating intermetallic compounds such as Al3Ti in the liquid phase (primary precipitation) during casting of the aluminum alloy without lowering the castability of the aluminum alloy, and can prevent cracks in the cast material. In addition, titanium can improve the mechanical properties and corrosion resistance of the aluminum alloy by increasing the precipitation of the intermetallic compound in the aluminum base by precipitation hardening heat treatment.

Titanium (Ti) is preferably included within the range of 0.001 to 0.2 wt % based on the total weight of the aluminum alloy.

When the composition range of titanium (Ti) is less than 0.001 wt %, the effect of adding titanium cannot be achieved.

On the other hand, when the composition range of titanium (Ti) is more than 0.2 wt %, since the intermetallic compound is generated in a large amount, there is a problem in that the mechanical properties of the alloy are lowered, and there is a problem in that the castability, weldability, and corrosion resistance of the alloy are lowered.

Calcium (Ca) improves the hardness, tensile strength, and elongation of the alloy by spherodizing the plate-shaped silicon (Si) in the aluminum alloy.

Calcium (Ca) is preferably included within the range of 0.001 to 0.2 wt % based on the total weight of the aluminum alloy.

Tin (Sn) improves the mechanical properties of the casting without reducing the thermal conductivity of the alloy in the aluminum alloy and improves the lubrication of mechanical parts that involve friction, such as bearings and bushings.

Tin (Sn) is preferably included within the range of 0.001 to 0.2 wt % based on the total weight of the aluminum alloy.

Unlike other alloy elements mentioned above, phosphorus (P) is an impurity that is easily incorporated during the refining and casting of aluminum. Therefore, when the content of phosphorus in the aluminum alloy increases, since the mechanical properties are lowered, the lower the content, the more advantageous it is. In addition, when a large amount of phosphorus (P) is included in the aluminum alloy, there is a problem in that the refinement of eutectic silicon (Si) in the molten metal cannot work effectively.

When the mixing of phosphorus in the process of refining and casting aluminum is unavoidable, phosphorus (P) is preferably included in an amount of less than 0.2 wt %.

Chromium (Cr) contributes to improving corrosion resistance by increasing the density of a magnesium oxide layer (MgO) film in the aluminum alloy, and can improve the strength and elongation, wear resistance, and heat resistance of the alloy through crystalline particle refinement.

Chromium (Cr) is preferably included within the range of 0.001 to 0.2 wt % based on the total weight of the aluminum alloy.

When the composition range of chromium (Cr) is less than 0.001 wt %, the effect of adding chromium cannot be achieved.

On the other hand, when the composition range of chromium (Cr) is more than 0.2 wt %, there is a problem in that the strength is rather lowered.

Zirconium (Zr) is an element that improves the strength of the alloy by creating a reinforced phase of Al3Zr in the aluminum alloy. On the other hand, zirconium has a higher melting point than aluminum, so that there is a downside to mass production in melting through conventional high-pressure die casting.

Accordingly, zirconium (Zr) is preferably included within the range of 0.001 to 0.2 wt % based on the total weight of the aluminum alloy.

Nickel (Ni) may improve the hot hardness of the aluminum alloy and the corrosion resistance of the alloy. On the other hand, nickel (Ni) may contribute to the improvement of the heat resistance of the aluminum alloy, but the effect is insignificant, and on the contrary, as an impurity that can be added to aluminum, when it is contained at more than 0.2 wt %, it may cause corrosion of the material.

Strontium (Sr) may improve strength and elongation by refining and spheroidizing eutectic Si in the aluminum alloy. However, when strontium is excessively added, brittleness increases and strength properties may be lowered, and furthermore, gas incorporation and compound formation may be promoted.

Accordingly, strontium (Sr) is preferably included within the range of 0.001 to 0.1 wt % based on the total weight of the aluminum alloy.

Vanadium (V), as a component included in a content of 0.001 to 0.01 wt %, plays an important role in allowing the aluminum alloy to be processed into a product by high-pressure die casting.

In addition, the aluminum alloys applied to the heat transfer member of the present disclosure have an electrical conductivity of 30 to 40% IACS and a thermal conductivity of 145 W/mK or more at a temperature of 25° C. or more. Therefore, they can be widely applied to electronic device parts, electric device parts, and automobile parts that require excellent (fast) heat transfer properties. In particular, it is more preferable that the aluminum alloy applied to the heat transfer member of the present disclosure has a thermal conductivity of 145 to 165 W/mK at a temperature of 25 to 200° C.

Hereinafter, referring to FIGS. 1 to 7, the thermal conduction performance and heat dissipation performance between the aluminum alloy applied to the heat transfer member of the present disclosure and the conventional aluminum alloy of the Comparative Example will be compared and described in detail.

Table 1 shows the results of measuring thermal conductivity, specific heat, and density between four aluminum alloys applied to the heat transfer member of the present disclosure and one conventional aluminum alloy (Alloy A383 alloy) of the Comparative Example.

As shown in Table 1, it can be seen that the aluminum alloys corresponding to the Examples of the present disclosure and the aluminum alloy of the Comparative Example exhibit different properties.

TABLE 1 Thermal Specific conductivity heat Density Classification (W/m · K) (J/(g · K) (g/cm3) Example-148 148.829 0.875 2.678 Example-150 150.874 0.875 2.678 Example-155 155.465 0.875 2.678 Example-162 162.603 0.875 2.678 Comparative 96.1 0.963 2.690 Example

FIG. 1 is a diagram schematically illustrating a method for measuring thermal conductivity of Table 1 and FIG. 2 to be described below.

As shown in FIG. 1, the thermal conductivity characteristic is the result of a measuring, over time, the temperature of an end point located opposite to a fixed end of a specimen of a predetermined size while maintaining a thermally insulated state from the outside for approximately 500 seconds, which is the test time, and maintaining the fixed end at 80° C. As a result of the thermal conductivity measurement, it was found that the thermal conductivity of the aluminum alloy specimens of the Examples of the present disclosure had improved by about 36% compared to the specimen of the Comparative Example.

The heat dissipation properties of aluminum in the present disclosure were measured according to the method shown in FIG. 3. Specifically, the evaluation of the heat dissipation properties was determined by maintaining the external temperature at an air-cooled room temperature of 25° C. and measuring the temperature, over time, of the measurement point for 15 seconds while maintaining the fixed end of the specimen of a predetermined size at 100° C.

As a result of measuring the heat dissipation properties, it was found that the heat dissipation property of the aluminum alloy specimens applied to the heat transfer member of the present disclosure had improved by about 47% compared to the aluminum alloy specimen of the Comparative Example (FIG. 4).

Tables 2 to 4 and FIGS. 5 to 7 below quantitatively show the effect of the addition of alloy elements on the thermal conductivity properties of the aluminum alloys applied to the heat transfer member of the present disclosure.

The thermal conductivity of Tables 2 to 4 and FIGS. 5 to 7 below was measured according to ASTM E146 (Standard Test Method for Thermal Diffusivity by the Flash Method).

Specifically, first, when the thermal diffusivity (α) is measured, and the density (ρ) and specific heat (cp) of the specimen are measured, the thermal conductivity (λ) is calculated by the following equation.


λ=α*ρ*cp

Table 2 below is a result of measuring the thermal conductivity according to the composition range of Mg in the aluminum alloys applied to the heat transfer member of the present disclosure in a state in which the composition ranges of Si and Fe are substantially fixed.

TABLE 2 Thermal Main Component (%) Conductivity Classification Si Fe Mg (W/mK) Example 1-1 8.61 0.49 0.05 147 Example 1-2 8.60 0.50 0.12 155 Example 1-3 8.60 0.51 0.20 160 Example 1-4 8.61 0.49 0.25 151 Comparative 8.62 0.50 0.32 125 Example 1-1 Comparative 8.60 0.50 0.41 119 Example 1-2 Comparative 8.60 0.49 0.52 111 Example 1-3

FIG. 5 shows the results of measuring the thermal conductivity of the aluminum alloys applied to the heat transfer member of the present disclosure and the aluminum alloys of the Comparative Examples according to Table 2 above.

As shown in the results of Table 2 and FIG. 5, the thermal conductivity of the Examples in which the composition range of Mg is at least 0.02 to 0.25 wt % is much higher than the thermal conductivity of the Comparative Examples in which the composition range of Mg is 0.3 wt % or more.

Table 3 below is a result of measuring the thermal conductivity according to the composition range of Fe in the aluminum alloys applied to the heat transfer member of the present disclosure in a state in which the composition ranges of Si and Mg are substantially fixed.

TABLE 3 Thermal Main Component (%) Conductivity Classification Si Fe Mg (W/mK) Example 2-1 8.60 0.40 0.03 154 Example 2-2 8.61 0.44 0.03 155 Example 2-3 8.60 0.48 0.04 155 Example 2-4 8.60 0.52 0.03 156 Comparative 8.60 0.30 0.04 145 Example 2-1 Comparative 8.60 0.70 0.04 147 Example 2-2 Comparative 8.60 0.76 0.05 145 Example 2-3 Comparative 8.59 0.81 0.03 141 Example 2-4

FIG. 6 shows the results of measuring the thermal conductivity of the aluminum alloys applied to the heat transfer member of the present disclosure and the aluminum alloys of the Comparative Examples according to Table 3 above.

As shown in the results of Table 3 and FIG. 6, the thermal conductivity of the Examples in which the composition range of Fe is at least 0.35 to 0.55 wt % is higher than the thermal conductivity of the Comparative Examples in which the composition range of Fe is less than 0.35 wt % or more than 0.55 wt %.

Table 4 below is a result of measuring the thermal conductivity according to the composition range of Si in the aluminum alloys applied to the heat transfer member of the present disclosure in a state in which the composition ranges of Fe and Mg are substantially fixed.

TABLE 4 Thermal Main Component (%) Conductivity Classification Si Fe Mg (W/mK) Example 3-1 8.20 0.36 0.28 164 Example 3-2 8.40 0.35 0.29 162 Example 3-3 8.60 0.35 0.28 160 Example 3-4 8.80 0.35 0.28 158 Comparative 9.50 0.36 0.29 142 Example 3-1 Comparative 12.50 0.35 0.30 127 Example 3-2

FIG. 7 shows the results of measuring the thermal conductivity of the aluminum alloys applied to the heat transfer member of the present disclosure and the aluminum alloys of the Comparative Examples according to Table 4 above.

As shown in the results of Table 4 and FIG. 7, the thermal conductivity of the Examples in which the composition range of Si is at least 8.0 to 9.0 wt % is higher than the thermal conductivity of the Comparative Examples in which the composition range of Si is more than 9 wt %.

FIG. 8 shows die casting simulation conditions of a cooling fin that is an embodiment of the heat transfer member of the present disclosure.

FIGS. 9 to 13 show simulation results of die casting characteristics according to the curvature value (R value) of a connection portion of the cooling fin, which is an embodiment of a heat transfer member of the present disclosure.

The shape of the cooling fin in FIGS. 8 to 13 corresponds only to one example of the heat transfer member of the present disclosure, and the heat transfer member of the present disclosure is not necessarily limited to the shapes shown in FIGS. 8 to 13. In other words, the heat transfer member of the present disclosure is not necessarily used only as a plurality of fin-shaped fins. For example, when the heat transfer member of the present disclosure is a pin-shaped cooling fin, the pin-shaped cooling fin may be used in the shape of only a single pin, or may also be used in the shape of a pin having a hollow portion.

As shown in FIG. 8, the simulation used a cooling fin structure including a base plate, a plurality of straight fin-shaped fins, and a connection portion (curvature portion) connecting the base plate and the fins. First, the parameters used in the simulation are as follows.

The temperature of the molten metal was 680° C. (700° C. based on the furnace), SKD61 which is an alloy for representative die-casting mold, was used for the mold, and the mold was heated to 180° C.

Other injection conditions of molten metals are summarized in the table of FIG. 9.

FIGS. 9 to 13 show simulation results of die casting characteristics according to the curvature value (R value) of a connection portion of the cooling fin, which is an embodiment of the heat transfer member of the present disclosure.

FIG. 9 shows simulation results when the R value of the connection portion (R portion) is 1 mm.

As shown in FIG. 9, when the R value was 1 mm, the molten metal was scattered to the top of the fin. When the R value is too low, the molten metal is not evenly introduced into the fin, and a portion of the molten metal is introduced into the fin first, so that the microstructure of the fin becomes uneven due to the solidification of the molten metal introduced first, and in severe cases, the solidified molten metal blocks a portion of the fin, thereby blocking the subsequent entry of the molten metal into the fins, resulting in a defective fin shape.

FIG. 10 shows simulation results when the R value of the connection portion (R portion) is 2 mm.

As shown in FIG. 10, when the R value was 2 mm, similar results were obtained to the results when the R value was 1 mm. However, the degree of scattering of the molten metal was predicted to be lower when the R value was 2 mm than when the R value was 1 mm.

FIG. 11 shows simulation results when the R value of the connection portion (R portion) is 3 mm.

When the R value was 3 mm, the degree of scattering of the molten metal was predicted to be very good, compared to the case where the R value was 1 mm or 2 mm.

Meanwhile, in general, when a curvature radius of the connection portion is large, fine bubbles contained in the molten metal gather in the connection portion, and an air isolation phenomenon is likely to occur. When the air isolation phenomenon occurs, the isolated air becomes a cavity after solidification, causing great problems in mechanical properties. When the R value was 3 mm, the occurrence of air isolation was predicted to be very less.

FIGS. 12 and 13 show simulation results when the R values of the connection portion (R portion) are 4 mm and 5 mm, respectively.

When the R value was 4 mm or 5 mm, more air isolation occurred compared to the case where the R value was 3 mm, and the frequency of air isolation was predicted to increase as the R value increased.

As described above, the aluminum alloys applied to the heat transfer member of the present disclosure can secure superior electrical conductivity, formability, and thermal conductivity compared to conventional commercial alloys by controlling the composition ratio of silicon, iron, and magnesium. Through this, the aluminum alloys applied to the heat transfer member of the present disclosure provide an effect that can be used for various parts requiring heat dissipation properties.

In addition, the aluminum alloys applied to the heat transfer member of the present disclosure control the composition ratio of silicon, iron, and magnesium and further includes copper and manganese, thereby providing an effect of further improving the thermal conduction and heat dissipation property and further improving castability at the same time compared to the conventional aluminum alloy.

In addition, the aluminum alloys applied to the heat transfer member of the present disclosure further include zinc, titanium, calcium, tin, phosphorus, chromium, zirconium, nickel, strontium, and vanadium, thereby providing an effect of improving castability and electrochemical properties, improving the lubrication and mechanical properties of mechanical parts, improving heat resistance and corrosion resistance, and improving the hot hardness and tensile strength of the alloy.

A heat transfer member of the present disclosure provides an effect that can be used for various parts that require rapid heat dissipation or heating by securing excellent electrical conductivity, thermal conductivity, and formability compared to a heat transfer member using conventional aluminum alloys, by applying a new aluminum alloy with a controlled composition ratio of silicon, iron, and magnesium in an aluminum base.

The present disclosure described above can be embodied in various other forms without departing from the technical spirit or main features thereof. Accordingly, the above embodiments are merely exemplary in all respects and should not be construed as limiting.

Claims

1. A heat transfer member made of an aluminum alloy comprising, based on a total amount of the alloy:

8.0 to 9.0 wt % of silicon (Si);
0.35 to 0.55 wt % of iron (Fe);
0.02 to 0.3 wt % of magnesium (Mg); and
a balance of aluminum.

2. The heat transfer member of claim 1, wherein the alloy includes at least one or two or more of:

0.001 to 0.2 wt % of copper (Cu);
0.001 to 0.2 wt % of manganese (Mn);
0.001 to 0.2 wt % of zinc (Zn);
0.001 to 0.2 wt % of titanium (Ti);
0.001 to 0.2 wt % of calcium (Ca);
0.001 to 0.2 wt % of tin (Sn);
0.001 to 0.2 wt % of phosphorus (P);
0.001 to 0.2 wt % of chromium (Cr);
0.001 to 0.2 wt % of zirconium (Zr);
0.001 to 0.2 wt % of nickel (Ni);
0.001 to 0.1 wt % of strontium (Sr); and
0.001 to 0.01% wt % of vanadium (V).

3. The heat transfer member of claim 1, wherein the alloy has an electrical conductivity of 30 to 40% IACS and a thermal conductivity of 145 to 165 W/mK at a temperature of 25 to 200° C.

4. The heat transfer member of claim 1, wherein the iron (Fe) is precipitated as iron aluminide (Al3Fe).

5. The heat transfer member of claim 2, wherein the iron (Fe) is precipitated as iron aluminide (Al3Fe).

6. The heat transfer member of claim 1,

wherein the silicon (Si) is combined with the magnesium (Mg) and precipitated as magnesium silicide (Mg2Si), and
wherein a remaining amount of the 8.0 to 9.0 wt % of the silicon (Si) is precipitated alone.

7. The heat transfer member of claim 2,

wherein the silicon (Si) is combined with the magnesium (Mg) and precipitated as magnesium silicide (Mg2Si), and
wherein a remaining amount of the 8.0 to 9.0 wt % of the silicon (Si) is precipitated alone.

8. The heat transfer member of claim 1, comprising:

a base plate;
at least one or more fins; and
a connection portion connecting the base plate and the fin.

9. The heat transfer member of claim 8, wherein the connection portion has a curvature radius of 3 mm.

10. The heat transfer member of claim 8, wherein the cooling fin is a straight fin, a pin fin, a wave fin, or a conical fin.

11. The heat transfer member of claim 10, wherein the cooling fin has a hollow shape.

Patent History
Publication number: 20240125566
Type: Application
Filed: Apr 13, 2023
Publication Date: Apr 18, 2024
Applicant: Lemon Metal Inc. (Seongnam-si)
Inventors: Se Joon HWANG (Seongnam-si), Han Goo KIM (Seongnam-si), Kwang Hoon PARK (Incheon)
Application Number: 18/134,120
Classifications
International Classification: F28F 21/08 (20060101); C22C 21/02 (20060101);