KR102257374B1 - Aluminum composite material for brake disk having improved hardness and wear resistance, and method for manufacturing the same - Google Patents

Abstract

The present invention relates to an aluminum composite material for a brake disk having improved hardness and wear resistance and a manufacturing method thereof and, more specifically to an aluminum composite material for a brake disk having improved hardness and wear resistance and a manufacturing method thereof, the aluminum composite material manufactured by mixing a powder-type aluminum alloy with a powder-type first reinforcing material made of SiC and a powder-type second reinforcing material made of SiC and having a larger particle size than the first reinforcing material.

Description

Aluminum composite material for brake disc with improved hardness and wear resistance and manufacturing method thereof

The present invention relates to an aluminum composite material for brake discs having improved hardness and wear resistance and a method for manufacturing the same, and more particularly, to an aluminum alloy in powder form, a first reinforcing material in powder form made of SiC, and a first reinforcing material made of SiC and first The present invention relates to an aluminum composite material for brake discs having improved hardness and abrasion resistance, manufactured by mixing a second reinforcing material in the form of a powder having a larger particle size than the reinforcing material, and a method for manufacturing the same.

Currently, as a material for a brake disc, which is one of the parts of automobiles, cast iron, which has advantages such as excellent strength, excellent wear resistance, and low price, is mainly used.

However, cast iron has various problems such as increasing the weight of the vehicle due to its relatively heavy characteristics compared to other metals, thereby decreasing the fuel efficiency of the vehicle, lowering the acceleration performance, and increasing the carbon dioxide emission.

Accordingly, in recent years, interest in reducing the weight of the brake disc in order to reduce environmental pollution and save energy is increasing.

In particular, attempts are being made to replace cast iron with aluminum alloy in order to reduce the weight of the material for the brake disc.

However, aluminum alloy has a problem in that it is difficult to apply to a brake disc because it is lighter than cast iron but exhibits low mechanical properties and low wear resistance, and it is necessary to improve it.

Registered Republic of Korea Patent Publication No. 10-1901318, 2018.09.17.

It is an object of the present invention to provide an aluminum composite material with improved hardness and wear resistance capable of providing an aluminum composite material with improved hardness and wear resistance, and a method for manufacturing the same.

Objects of the present invention are not limited to the objects mentioned above, and other objects not mentioned will be clearly understood from the description below.

The aluminum composite material for a brake disc with improved hardness and wear resistance according to the present invention for achieving the above object is 14 to 16 parts by weight of silicon, 2.4 to 2.8 parts by weight of copper, 0.5 to 0.8 parts by weight of magnesium, and 80 to 83 parts by weight of aluminum. 100 parts by weight of an aluminum alloy, 3 to 4 parts by weight of a first reinforcing material made of SiC, and 2 to 3 parts by weight of a second reinforcing material made of SiC and having a particle size relatively larger than that of the first reinforcing material.

According to the present invention for achieving the above object, there is provided a method for manufacturing an aluminum composite material for brake disc with improved hardness and wear resistance, 14 to 16 parts by weight of silicon, 2.4 to 2.8 parts by weight of copper, 0.5 to 0.8 parts by weight of magnesium, and 80 to 83 parts by weight of aluminum. To compose a mixed powder by mixing a powder-type aluminum alloy made of negative with a powder-type first reinforcing material made of SiC and a powder-type reinforcing material made of SiC and having a particle size relatively larger than that of the first reinforcing material step; Forming a sintered body by putting the mixed powder composition into a mold, raising the temperature from room temperature to a first preset temperature in a preset vacuum atmosphere and uniaxial pressure condition, and then sintering at the first temperature for a preset time; cooling the sintered body; heating the cooled sintered body and maintaining it at a second temperature lower than the first temperature for a preset time, followed by quenching to solution heat treatment; and heating the solution-treated sintered body, maintaining it at a third temperature lower than the second temperature for a preset time, and then performing an aging treatment by air cooling.

According to the embodiment of the present invention according to the above-described configuration, the aluminum alloy is mixed with a powder-type first reinforcing material made of SiC and a powder-type second reinforcing material made of SiC and having a relatively larger particle size than the first reinforcing material. The manufactured aluminum composite material may have higher hardness and higher wear resistance than the aluminum composite material manufactured by mixing an aluminum alloy with a powder-type SiC reinforcement having a single particle size.

1 is a flowchart of a method for manufacturing an aluminum composite material for a brake disc having improved hardness and wear resistance according to an embodiment of the present invention.
2 is a graph showing hardness values of specimens according to Examples and Comparative Examples 1 to 3 of the present invention.
3 is a graph showing specific wear rate values of specimens according to Examples and Comparative Examples 1 to 3 of the present invention.
4 is an image of the wear track of the specimen according to the embodiment of the present invention observed with a scanning electron microscope (Scanning Electron Microscope).
5 is an image of a fragment that is worn off from a specimen according to an embodiment of the present invention observed with a scanning electron microscope.
6 is an image of observing fragments worn away from a specimen according to an embodiment of the present invention with an Energy Dispersive X-Ray Spectrometer (EDS).
7 is an image obtained by observing a wear track of a specimen according to Comparative Example 1 with a scanning electron microscope.
8 is an image obtained by observing the fragments worn off from the specimen according to Comparative Example 1 with a scanning electron microscope.
FIG. 9 is an image observed by EDS of fragments worn away from the specimen according to Comparative Example 1. FIG.
10 is an image of a wear track of a specimen according to Comparative Example 2 observed with a scanning electron microscope.
11 is an image obtained by observing the fragments worn off from the specimen according to Comparative Example 2 with a scanning electron microscope.
FIG. 12 is an image observed by EDS of fragments worn away from the specimen according to Comparative Example 2. FIG.
13 is an image of a wear track of a specimen according to Comparative Example 3 observed with a scanning electron microscope.
14 is an image obtained by observing fragments worn off from a specimen according to Comparative Example 3 with a scanning electron microscope.
15 is an image observed by EDS of fragments worn away from the specimen according to Comparative Example 3;
16 is a graph showing friction coefficient values for each wear time of specimens according to Examples and Comparative Examples of the present invention.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms different from each other, and only these embodiments make the disclosure of the present invention complete, and those of ordinary skill in the art to which the present invention pertains. It is provided to fully inform the person of the scope of the invention. On the other hand, the terms used in the present specification are for describing the embodiments, and are not intended to limit the present invention. In this specification, the singular form also includes the plural form unless specifically stated in the phrase.

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

1, the method for manufacturing an aluminum composite material for brake disc with improved hardness and wear resistance of the present invention comprises a mixed powder composition step (S100), a mixed powder mixing step (S200), a sintered body forming step (S300), a sintered body cooling step ( S400), a solution heat treatment step (S500), may include an aging treatment step (S600).

First, the mixed powder composition step (S100) may be to form a mixed powder by mixing a first reinforcing material made of SiC in an aluminum alloy and a second reinforcing material made of SiC and having a particle size relatively larger than that of the first reinforcing material.

The mixed powder may consist of 100 parts by weight of the aluminum alloy, 3 to 4 parts by weight of the first reinforcing material, and 2 to 3 parts by weight of the second reinforcing material.

The aluminum alloy may include 14 to 16 parts by weight of silicon, 2.4 to 2.8 parts by weight of copper, 0.5 to 0.8 parts by weight of magnesium, and 80 to 83 parts by weight of aluminum.

The first reinforcing material may be made of SiC having a particle size of 35 μm to 42 μm.

The second reinforcing material may be made of SiC and have a particle size of 63 μm to 75 μm.

Here, the mixing of the first reinforcing material and the second reinforcing material having different particle sizes is to have a higher packing density than that of using particles of a single size.

That is, when the first reinforcing material and the second reinforcing material are mixed, the filling density of the mixed powder increases while the first reinforcing material is filled in the empty space between the second reinforcing materials, so that in the sintered body forming step (S300) performed later, the size of single particles It is possible to achieve the effect of improving hardness and wear resistance by increasing the sintering density than using

Next, the mixing powder mixing step ( S200 ) may be a mixing process such that the powder in which the aluminum alloy and the first reinforcement material and the second reinforcement material are mixed are evenly mixed.

That is, the mixed powder mixing step ( S200 ) may be to put the mixed powder into a container provided in the 3D mixer so that the mixed powder is evenly mixed, and then perform the mixing process at a constant speed for a predetermined time.

In this case, the mixing speed according to the 3D mixer may be 45 RPM. And mixing can be done for 24 hours.

Next, the sintered compact forming step (S300) may be a sintering treatment by putting the mixed powder into a mold.

That is, the sintered body forming step (S300) is to put a mold in which the mixed powder is put into the inside of a vacuum chamber equipped with a hot press, and raise the temperature while uniaxially pressing the input mold with a hot press to sinter for a certain period of time. .

의 진공분위기로 조성될 수 있다. 그리고 핫프레스에 따른 일축 압력은 60MPa 내지 80MPa일 수 있다.At this time, the inside of the vacuum chamber is

It can be created in a vacuum atmosphere of And the uniaxial pressure according to the hot press may be 60 MPa to 80 MPa.

In addition, the sintering treatment may be performed for 30 minutes to 90 minutes after the hot press is heated from room temperature to 550° C. to 600° C. at a rate of 5° C./min to 15° C./min.

Then, the aluminum alloy constituting the mixed powder, the first reinforcement, and the second reinforcement may be a sintered body having a shape corresponding to the inner shape of the molding die.

의 진공분위기, 60MPa 내지 80Mpa의 일축 압력, 5℃/min 내지 15℃/min의 승온 속도, 550℃ 내지 600℃에서 30분 내지 90분 동안 소결하는 조건을 벗어나게 되면 소결체에 다수의 기공이 발생하는 등 소결이 제대로 이루어지지 않으므로, 최종적으로 완성된 알루미늄 복합재료의 기계적 특성을 저하시킬 수 있다. Meanwhile,

of vacuum atmosphere, uniaxial pressure of 60 MPa to 80 Mpa, temperature increase rate of 5 ° C / min to 15 ° C / min, 550 ° C to 600 ° C. Since sintering is not performed properly, the mechanical properties of the finally finished aluminum composite material may be deteriorated.

Next, the step of cooling the sintered body (S400) may be to slowly cool the sintered body sintered at 550 °C to 600 °C.

That is, the step of cooling the sintered body ( S400 ) may be to slowly cool the sintered body to room temperature by putting the sintered body into a furnace at a temperature of 550° C. to 600° C.

Next, the solution heat treatment step (S500) may be to put the cooled sintered body into the furnace, and to rapidly cool the furnace after maintaining it for a certain period of time by raising the temperature.

At this time, the interior of the furnace may be created in an argon atmosphere to minimize the reaction with the air by blocking the air. And the temperature increase rate of the furnace may be 5 ℃ / min to 15 ℃ / min. When the furnace is heated and the temperature of the sintered body reaches 450° C. to 490° C., the temperature of the sintered body is maintained for 30 to 90 minutes and then rapidly cooled.

The solution heat treatment step (S500) may be to heat the sintered body to 450° C. to 490° C. to form a solid solution state, and then rapidly cool the sintered body to maintain the solid solution state up to room temperature so that the sintered body becomes a supersaturated solid solution.

Next, the aging treatment step ( S600 ) may be to put the cooled sintered compact after the solution treatment into the furnace, raise the temperature of the furnace to maintain it for a certain period of time, and then air-cool it.

At this time, the interior of the furnace may be created in an argon atmosphere. And the temperature increase rate of the furnace may be 5 ℃ / min to 15 ℃ / min. When the furnace is heated and the temperature of the sintered body reaches 115° C. to 135° C., the temperature of the sintered body is maintained for 20 to 28 hours and then air-cooled.

On the other hand, the solution-treated sintered compact may be unstable at room temperature because it is rapidly cooled at 450°C to 490°C to become a supersaturated solid solution. Here, when the sintered body at room temperature is heated to 115° C. to 135° C., a precipitated phase may be formed by alloying elements in a supersaturated solid solution state of the sintered body in order to stabilize the supersaturated solid solution in an unstable state.

That is, in the solution heat treatment step (S500), the sintered body is heated to 450° C. to 490° C. to make it a solid solution state, and then quenched again to maintain the solid solution state to room temperature to make a supersaturated solid solution, and then, the aging treatment step (S600) By maintaining the treated sintered body at 115° C. to 135° C. for 20 to 28 hours and then air cooling to form a precipitated phase on the sintered body, the sintered body is age-hardened to have high hardness and high wear resistance.

Hereinafter, Examples of the method for manufacturing an aluminum composite material according to the present invention will be described in comparison with Comparative Examples.

[Example]

First, 94 g of aluminum alloy powder and 3.5 g of a first reinforcing material, which is a SiC powder having a particle size of 38 μm, and 2.5 g of a second reinforcing material, which is a SiC powder having a particle size of 63 μm, were mixed to form a mixed powder of 100 g.

100 g of the mixed powder was put into a 3D mixer and mixed at a speed of 45 RPM for 24 hours. 10g out of 100g of the mixed powder was put into a vacuum chamber equipped with a hot press in a state of being put into a mold.

의 진공분위기로 조성하였고 성형틀에 투입된 합금 분말을 핫프레스로 70MPa로 일축 가압하면서 10℃/min의 속도로 580℃까지 승온시킨 후 580℃를 60분동안 유지하면서 소결 처리하여 소결체를 형성하였다.Inside the vacuum chamber

A sintered body was formed by sintering the alloy powder put into the molding die at a rate of 10° C./min while uniaxially pressing at 70 MPa with a hot press to 580° C. and maintaining 580° C. for 60 minutes.

The formed sintered body was put into a furnace at 580° C. so that it reached room temperature, and then cooled slowly.

The cooled sintered compact was put into a furnace composed of an argon atmosphere, the furnace was heated to 470°C at a rate of 10°C/min, and then 470°C was maintained for 60 minutes from the time the furnace temperature reached 470°C. Thereafter, the sintered compact was water-cooled so that the sintered compact was rapidly cooled to room temperature.

The water-cooled sintered compact was put into a furnace composed of an argon atmosphere, the furnace was heated to 125°C at a rate of 10°C/min, and then 125°C was maintained for 24 hours from the time the furnace temperature reached 125°C. After that, the sintered body was air-cooled so that it was cooled to room temperature to prepare a specimen.

[Comparative Example 1]

In Comparative Example 1, a specimen was prepared in the same manner as in Example by composing the mixed powder with only 100 g of aluminum alloy powder.

[Comparative Example 2]

In Comparative Example 2, 100 g of a mixed powder was prepared by mixing 94 g of an aluminum alloy and 6 g of a second reinforcing material, which is a SiC powder having a particle size of 63 μm, to prepare a specimen by the same process as in Example.

[Comparative Example 3]

In Comparative Example 3, 100 g of a mixed powder was prepared by mixing 94 g of an aluminum alloy and 6 g of a first reinforcing material, which is a SiC powder having a particle size of 38 μm, to prepare a specimen by the same process as in Example.

[Test Example]

1. Specimen Pretreatment

In order to observe the hardness test, abrasion test, and the structure of each specimen of the specimens manufactured according to Examples and Comparative Examples 1 to 3, pretreatment for each specimen was required.

That is, when the microstructure of the specimen is observed, if the surface of the specimen is not flat, the image cannot be properly captured due to the low depth of focus. And if the surface of the specimen is not flat, it is difficult to accurately measure the characteristics of the worn specimen.

Therefore, in order to flatten the surface of the specimen, the specimens according to Examples and Comparative Examples 1 to 3 were polished with SiC emery paper, respectively, and then finely polished with diamond powder.

Here, the polishing was performed in the order of 1200 times, 1500 times, 2000 times, 2400 times, and 4000 times according to the roughness of the SiC emery paper.

SiC emery paper is coarser with lower numbers.

Fine polishing was performed in the order of 6 μm and 1 μm diamond powder.

After polishing and fine polishing the specimens according to Examples and Comparative Examples 1 to 3, respectively, each specimen was immersed in the etching solution for 3 seconds 4 times and then etched.

Here, the etching solution is a modified Keller reagent consisting of 175 ml of distilled water, 20 ml of HNO3, 3 ml of HCl, and 2 ml of HF.

2. Hardness test

In order to measure the hardness of the specimens according to Examples and the specimens according to Comparative Examples 1 to 3, an indentation hardness test was performed under the same conditions using a Vickers hardness tester. Here, the load applied to the hardness test was set to 4.9N.

The indentation diagonal length of the specimen according to Example is 0.14886 mm, the indentation diagonal length of the specimen according to Comparative Example 1 is 0.20045 mm, and the indentation diagonal length of the specimen according to Comparative Example 2 is 0.18409 mm, and the specimen according to Comparative Example 3 The diagonal length of the indentation was found to be 0.19018 mm.

The hardness values (HV) of the specimens according to Examples and Comparative Examples 1 to 3 were derived according to Equation 1 below, and Table 1 shows the hardness values (HV) of each specimen.

(Equation 1)

는 압자의 대면각을 나타낸다.Here, F in Equation 1 is the applied load, S is the surface area of the indentation, d is the diagonal length of the indentation,

denotes the facing angle of the indenter.

division Hardness value (HV) Example 41.82 Comparative Example 1 23.06 Comparative Example 2 27.34 Comparative Example 3 25.62

2 is a graph showing hardness values of specimens according to Examples and specimens according to Comparative Examples 1 to 3, wherein the horizontal axis indicates each specimen and the vertical axis indicates the hardness value (HV).

Referring to Table 1 and FIG. 2 , it was confirmed that the hardness values of the specimens according to Examples were higher than the hardness values of the specimens according to Comparative Examples 1 to 3.

In particular, it was confirmed that the specimens according to Examples had higher hardness values than the specimens according to Comparative Examples 2 and 3.

That is, it is determined that the hardness of the aluminum composite material manufactured by mixing reinforcing materials of different particle sizes is higher than that of the aluminum composite material manufactured by mixing the reinforcing material of a single particle size with an aluminum alloy.

3. Wear test

In order to compare the degree of abrasion and the abraded structure of the specimens according to Examples and the specimens according to Comparative Examples 1 to 3, each specimen was placed in a Ball on disk abrasion tester and abrasion tests were performed under the same conditions.

The wear test was conducted for 400 seconds under the conditions of a wear distance of 500m, a temperature of 25℃, a relative humidity of 60%, a wear radius of 11mm, a load of 50N, a linear speed of 1.25m/s, an RPM 1000, and the counterpart SUJ2.

In addition, the densities of the specimens according to Examples and the specimens according to Comparative Examples 1 to 3 are shown in Table 2 below.

division

)Theoretical Density
(

) actual density
(

) relative density
(%) Example 2.702 2.6846 99.36 Comparative Example 1 2.675 2.662 99.51 Comparative Example 2 2.702 2.681 99.22 Comparative Example 3 2.702 2.6826 99.28

(1) Comparison of wear and specific wear rates of each specimen

Table 3 shows the amount of wear and the specific wear rate of the specimens according to Examples and Comparative Examples 1 to 3. In addition, FIG. 3 schematically shows the specific wear rate according to each specimen as a graph, and the horizontal axis of FIG. 3 indicates each specimen and the vertical axis indicates the specific wear rate.

division wear
(g)

)specific wear rate
(

) Example 0.0023 0.0000344 Comparative Example 1 0.0188 0.000284 Comparative Example 2 0.0032 0.0000479 Comparative Example 3 0.0062 0.0000928

Referring to Table 3, the amount of wear of the specimens according to Examples and the specimens according to Comparative Examples 1 to 3 shows the difference between the mass before the wear test and the mass after the wear test, and the specific wear rate (W ') is below according to the wear test conditions. It was derived by Equation 2 of

(Equation 2)

은 마모 손실 질량,

는 마모 시간, p는 소재의 밀도, v는 마모 속도,

은 작용하중을 나타낸다.Here, in Equation 2

silver wear loss mass,

is the wear time, p is the density of the material, v is the wear rate,

represents the applied load.

Referring to Table 3, it was found that the wear amount of the specimen according to Example was the smallest, and the amount of wear of the specimen according to Comparative Example 1 was the largest.

And when the abrasion amount of the specimen according to Comparative Example 2 was compared with that of the specimen according to Comparative Example 3, it was found that the wear amount of the specimen according to Comparative Example 2 including a reinforcing material having a large particle size was less than that of Comparative Example 3.

In addition, referring to Table 3 and FIG. 3, the specific wear rate according to Equation 2 was derived from the lowest value in the specimen according to Example, and the highest value was derived in the specimen according to Comparative Example 1 in which the reinforcement was not included. .

And comparing the specific wear rate of the specimen according to Comparative Example 2 and the specific wear rate of the specimen according to Comparative Example 3, the specific wear rate of the specimen according to Comparative Example 2 containing a reinforcement material having a larger particle size than that of Comparative Example 3 was lower. appear.

That is, the second reinforcing material is included alone by showing the lowest wear amount and specific wear rate in the specimen according to the embodiment in which both the first reinforcing material having a particle size of 38 μm and the second reinforcing material having a particle size of 63 μm were included. It was confirmed that less wear occurred in the specimen according to Example 2 than the specimen according to Comparative Example 2 and the specimen according to Comparative Example 3 in which the first reinforcement was included alone.

(2) Comparison of wear tracks and wear debris

In order to confirm the reason why the least abrasion occurs in the specimen according to the embodiment, the wear track of each specimen and the fragments worn off from the specimen were observed with a scanning electron microscope.

In addition, the fragments worn away from the specimens were analyzed by EDS (Energy Dispersive X-Ray Spectrometer) to observe the amount of carbon contained in the fragments.

4 to 15 , the wear track, the structure of the fragment, and the distribution of carbon included in the fragment of the specimen according to the embodiment and the specimen according to Comparative Examples 1 to 3 can be confirmed.

First, FIG. 4 is a wear track of a specimen according to an embodiment, and it was confirmed that abrasive wear was mainly generated rather than adhesive wear. Here, 41 in FIG. 4 indicates that adhesive wear has occurred, and 42 indicates that abrasive wear has occurred.

7 is a wear track of a specimen according to Comparative Example 1, and it was confirmed that mainly adhesive wear rather than abrasive wear occurred. Here, 71 in FIG. 7 indicates that adhesive wear has occurred, and 72 indicates that abrasive wear has occurred.

FIG. 10 is a wear track of a specimen according to Comparative Example 2, showing a form of abrasive wear as a whole, but it was confirmed that adhesive wear occurred partially. Here, 101 in FIG. 10 indicates that adhesive wear has occurred, and 102 indicates that abrasive wear has occurred.

13 is a wear track of a specimen according to Comparative Example 3, and although the form of abrasive wear is partially shown, it was confirmed that adhesive wear of a larger scale than that of Comparative Example 2 occurred. Here, 131 in FIG. 13 indicates that adhesive wear has occurred, and 132 indicates that abrasive wear has occurred.

On the other hand, adhesive wear refers to a wear form in which the surface of a material is torn off by adhesion, and abrasive wear refers to wear caused by scratching without adhesion of a material. That is, since the amount of adhesive wear is greater than that of abrasive wear, the greater the amount of adhesive wear on the specimen during the wear test, the greater the amount of wear and the larger the size of the fragments may be.

5, 8, 11 and 14 show the fragment sizes of the specimens according to Examples and Comparative Examples 1 to 3, 51 in FIG. 5, 81 in FIG. 8, 111 in FIG. 11 and FIG. 14 141 represents the fragment of each specimen.

Referring to FIGS. 5, 8, 11 and 14 , it was confirmed that the size of the fragments was the smallest in the Example, and the size of the fragments was small in the order of Comparative Example 2, Comparative Example 3, and Comparative Example 1.

That is, it was confirmed that abrasive wear mainly occurred and the size of fragments was the smallest in the specimen according to the embodiment in which both the first reinforcement having a particle size of 38 μm and the second reinforcement having a particle size of 63 μm were included.

Through this, it was confirmed that less wear occurred in the specimen according to the embodiment than the specimen according to Comparative Example 2 including the second reinforcing material alone and the specimen according to Comparative Example 3 including the first reinforcing material alone.

In addition, FIGS. 6, 9, 12 and 15 show that fragments of the specimens according to Examples and Comparative Examples 1 to 3 were collected with a carbon tape using an EDS (Energy Dispersive X-Ray Spectrometer). As a result of the analysis, it is possible to confirm the distribution amount of carbon contained in the fragments separated from the specimens according to Examples and Comparative Examples 1 to 3 during the wear test.

Here, 61 in Fig. 6, 91 in Fig. 9, 121 in Fig. 12, and 151 in Fig. 15 indicate carbon contained in the fragment, 62 in Fig. 6, 92 in Fig. 9, 122 in Fig. 12, and 152 in Fig. 15 are Indicates the carbon represented by the carbon tape.

That is, referring to FIGS. 6, 9, 12 and 15 , the portion indicated by the dot inside the fragment indicates carbon contained in the fragment, and the portion indicated by the dot on the outside of the fragment indicates the carbon indicated by the carbon tape. .

As a result of confirming the amount of carbon distribution per unit area of the fragments for each specimen, almost no carbon was detected in the fragments of the specimen according to Comparative Example 1. This is a result that the reinforcing material is not included in the specimen according to Comparative Example 1.

In addition, when the carbon distribution amount of the fragments of the specimens according to Examples and the fragments of the specimens according to Comparative Examples 2 to 3 was compared, it was confirmed that the carbon distribution amount of the fragments of the specimens according to Examples was the smallest.

And it was confirmed that the carbon distribution amount of the fragment of the specimen according to Comparative Example 2 was smaller than the carbon distribution amount of the fragment of the specimen according to Comparative Example 3.

Here, the carbon contained in the fragments of each specimen is a reinforcing material that is worn away from each specimen, and it can be determined that the greater the distribution of carbon in the fragments of each specimen, the greater the amount of the reinforced material that is worn away.

That is, it can be seen that the specimen according to Comparative Example 2 including the second reinforcing material having a particle size of 63 μm withstands wear better than the specimen according to Comparative Example 3 including the first reinforcing material having a particle size of 38 μm. there was.

And in Comparative Examples 2 and 3, in which the specimens of Examples including both the first and second reinforcing materials having particle sizes of 38 μm and 63 μm included only the first reinforcing material or the second reinforcing material having a single particle size alone It was confirmed that the specimen resisted the abrasion better than the following specimen.

The specimens of Examples are judged to have superior wear resistance than Comparative Examples 1 to 3 by allowing the first reinforcement distributed therebetween to withstand friction even if the second reinforcement is worn off during the wear process.

(3) Comparison of average values of friction coefficient by wear time

16A is a graph showing the friction coefficient for each wear time of the specimen according to an embodiment of the present invention, FIG. 16B is a graph showing the friction coefficient for each wear time of the specimen according to the composition of the mixed powder with only 100 g of aluminum alloy powder, FIG. 16C is aluminum It is a graph showing the friction coefficient for each wear time of the specimen by mixing 94 g of the alloy and 6 g of the first reinforcing material, which is SiC powder having a particle size of 38 μm, to form 100 g of the mixed powder.

Here, in the graphs of FIGS. 16A to 16C , the horizontal axis represents the wear time, and the vertical axis represents the friction coefficient.

16a to 16c, the friction coefficient value for each wear time of the specimen according to the embodiment of the present invention compared to the friction coefficient value for each wear time of the comparative examples according to FIGS. 16b and 16c was found to appear most uniformly around 0.1 became

Those of ordinary skill in the art to which the present invention pertains will appreciate that the present invention can be implemented in other specific forms without changing the technical spirit or essential features thereof. Therefore, it should be understood that the embodiments described above are illustrative and non-limiting in all respects. The scope of the present invention is indicated by the following claims rather than the above detailed description, and all changes or modifications derived from the claims and their equivalent concepts should be construed as being included in the scope of the present invention.

S100: mixing powder composition step, S200: mixing powder mixing step,
S300: sintered compact forming step, S400: sintered compact cooling step,
S500: solution treatment step, S600: aging treatment step

Claims (6)

In 100 parts by weight of an aluminum alloy in powder form consisting of 14 to 16 parts by weight of silicon, 2.4 to 2.8 parts by weight of copper, 0.5 to 0.8 parts by weight of magnesium, and 80 to 83 parts by weight of aluminum, SiC and having a particle size of 35 μm to 42 μm composing a mixed powder by mixing 3 to 4 parts by weight of a first reinforcing material in the form of phosphorus powder and 2 to 3 parts by weight of a second reinforcing material in the form of a powder consisting of SiC and having a particle size of 63 μm to 75 μm;
Forming a sintered body by putting the mixed powder composition into a mold, raising the temperature from room temperature to a first preset temperature in a preset vacuum atmosphere and uniaxial pressure condition, and then sintering at the first temperature for a preset time;
cooling the sintered body;
heating the cooled sintered body and maintaining it at a second temperature lower than the first temperature for a preset time, followed by quenching to solution heat treatment; and
Including; heating the solution-treated sintered body and maintaining it for a predetermined time at a third temperature lower than the second temperature, followed by air cooling and aging treatment; including
Abrasion test using a ball on disk abrasion tester for 400 seconds under the conditions of abrasion distance of 500m, temperature 25℃, relative humidity 60%, wear radius 11mm, load 50N, linear speed 1.25m/s, RPM 1000, and SUJ2 counterpart. Characterized in that it is possible to manufacture an aluminum composite material having a specific wear rate of 0.0000344 mm ^{3 /N m calculated by the following Equation 1}
A method for manufacturing an aluminum composite material for brake discs with improved hardness and wear resistance.
(Equation 1)

Here, W' is the specific wear rate, Δm is the wear loss mass, Δt is the wear time, p is the density of the material, v is the wear rate, and F _N is the applied load. The method of claim 1,
The step of forming the sintered body,
Put the mixed powder into the mold,

Hardness and abrasion resistance, characterized in that the temperature is raised from room temperature to 550°C to 600°C at a rate of 5°C/min to 15°C/min in a vacuum atmosphere of 60 MPa to 80 MPa and uniaxial pressure of 60 MPa to 80 MPa, followed by sintering for 30 minutes to 90 minutes This improved method for manufacturing aluminum composites for brake discs. delete delete 100 parts by weight of an aluminum alloy comprising 14 to 16 parts by weight of silicon, 2.4 to 2.8 parts by weight of copper, 0.5 to 0.8 parts by weight of magnesium, and 80 to 83 parts by weight of aluminum;
3 to 4 parts by weight of a first reinforcement made of SiC and having a particle size of 35 μm to 42 μm;
Containing 2 to 3 parts by weight of a second reinforcing material made of SiC and having a particle size of 63 μm to 75 μm,
Abrasion test using a ball on disk abrasion tester for 400 seconds under the conditions of abrasion distance of 500m, temperature 25℃, relative humidity 60%, wear radius 11mm, load 50N, linear speed 1.25m/s, RPM 1000, and SUJ2 counterpart. When the specific wear rate calculated and measured by the following Equation 1 is 0.0000344mm ³ /N·m
An aluminum composite material composition for brake discs with improved hardness and wear resistance.
(Equation 1)

Here, W' is the specific wear rate, Δm is the wear loss mass, Δt is the wear time, p is the density of the material, v is the wear rate, and F _N is the applied load. delete

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