KR101627461B1 - a manufacturing method of aluminum composite reinforced by aluminum nitride and an aluminum composite manufactured by the same method - Google Patents

Abstract

The present invention relates to a method for producing an aluminum composite material reinforced by aluminum nitride and an aluminum composite material produced thereby. The present invention is characterized in that molten Al is contacted with an Al powder bed or a preformed body containing carbon in a nitrogen atmosphere to produce an AlN reinforced Al-base matrix composite. According to the present invention, molten Al spontaneously penetrates into the Al powder containing carbon under atmospheric pressure to form AlN, and various alkaline earth metals other than Mg can be used as the auxiliary alloy element. In addition, according to the present invention, the AlN-Al composite material can be manufactured in a very short time at a temperature as low as 1,000 ° C or less since the process is simple and does not require a complicated device, and therefore is economical and highly effective in reducing production costs.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an aluminum composite material,

The present invention relates to a method for producing an aluminum composite material reinforced by aluminum nitride and an aluminum composite material produced thereby.

Traditionally metal matrix composites (MMCs) with reinforcing phases in metal bases have been used in a variety of processes such as powder metallurgy, spray deposition, mechanical alloying (MA) and various casting methods (squeeze casting, rheocasting and compocasting) And the strengthened phase is integrated into the metal base.

However, since the MMCs prepared by this method use expensive reinforced phases manufactured through artificially separate processes, the cost of the composite material produced is high. Furthermore, the strengthening phase can contaminate the surface during manufacture or storage, and such contamination can increase the interfacial energy between the metal matrix and the reinforcing phase in the composite material produced. As a result, the interface strength may be weakened and the mechanical properties may be deteriorated. In addition, the reinforcing phases can form undesirable reaction products that can degrade the properties of the composite by reacting with the matrix during the fabrication process of the composite, the secondary process, and long periods of use.

In addition, since wettability between the molten metal and the ceramic reinforced phase is generally poor, additional processes (or equipment), such as vacuum or pressurization, are required to disperse the reinforcing phases in the metal matrix. However, this may increase the manufacturing cost of MMCs because it requires additional cost.

It is well known that the properties of MMCs can be controlled by the nature of the interface between the matrix and the reinforcing phase, the size and shape of the reinforcing phase, and the volume fraction of the reinforcing phase, which are characterized by a fine, thermodynamically stable, And can be obtained when dispersed. However, when manufacturing MMCs using existing MMCs manufacturing processes, there is a limit to meet the above conditions.

To overcome these limitations, there is an increasing interest in in situ MMCs characterized in that a thermodynamically stable strengthening phase is formed by chemical reaction at the metal matrix during the manufacture of MMCs.

In situ MMCs have the advantage of being able to produce a composite material in which the reinforcing phase is uniformly distributed within the matrix, without the problem of wettability with the matrix metal, because the thermodynamically stable reinforcing phase is formed within the matrix itself.

In situ MMCs can also control the type, size, and volume fraction of reinforcing phases formed by themselves by changing the manufacturing conditions. Thus, composite materials reinforced with a high volume fraction of ceramics can be manufactured can do.

To date, PRIMEX and DIMOX processes (Aghajanian MK, Rocazella MA, Burke JT, Keck SD (1991), J Mater Sci 6: 447, AW Urquhart, Mater. Sci. (1991) 75), Martin Marietta's XD process (ZY Ma, JH Li, M. Luo, XG Ning, YX Lu, J. Bi, YZ Zhang, A variety of manufacturing processes have been developed such as propagating high-temperature synthesis (AG Merzhanov, IP Borovinskaya, Dokl. Akad. Nauk. SSSR 204 (1972) 366).

In recent years, interest has been growing in Al-AlN composites, especially AlN, which has high thermal conductivity, low thermal expansion coefficient (comparable to the thermal expansion coefficient of Si), high electrical conductivity, excellent mechanical strength and excellent chemical stability , Which is an intensive interest for packaging materials and reinforced composites of structural materials. Furthermore, since AlN does not react with Al, there is no problem of property deterioration of the composite material due to the interfacial reaction product.

According to U. S. Patents 4,713, 360, it is disclosed that when a molten Al alloy is exposed to a nitriding atmosphere, AlN is formed from the molten Al alloy surface.

Zheng et al. (Advanced Eng. Mat. 5 (2003) 167) reported that Al (or Al alloy) was heated to 1,050 ℃ ~ 1,300 ℃ and bubbled with high purity methane, nitrogen and ammonia gas Reinforced Al composites were fabricated and the oxygen partial pressure and water content were found to affect the formation of AlN. They report that AlN is not formed in the commercial nitrogen atmosphere and that the degree of AlN formation is not large even in the deoxidized nitrogen gas.

U.S. Patent 4,713,360

Zheng et al. (Advanced Eng. Mat, 5 (2003) 167)

An object of the present invention is to provide a method for manufacturing an aluminum composite material reinforced by aluminum nitride which is simple and inexpensive in process and high in yield (easy control of volume fraction), and an aluminum composite material produced thereby.

According to an aspect of the present invention, there is provided a method for manufacturing a honeycomb structure, comprising the steps of: heat treating an air-permeable powder bed or a preform including an Al powder and carbon in a nitrogen atmosphere to convert the Al powder into AlN, Or a step of spontaneously infiltrating into the void of the preform and then solidifying the AlN-reinforced Al composite material.

The Al powder may comprise pure Al powder or Al alloy powder.

The molten Al may be pure Al ingot or molten Al alloy ingot.

The nitrogen atmosphere may have a nitrogen concentration of 10-100 vol%.

The heat treatment is performed at 700 ° C to 1,000 ° C, and more preferably 750 ° C to 1000 ° C.

Al alloy powder or Al alloy ingot may contain Mg.

The carbon may include at least one member selected from the group consisting of lamp carbon, acetylene carbon, sugar, glucose, melamine, and combinations thereof.

The powder bed or preform may comprise at least one member selected from the group consisting of oxides, carbides, borides, nitrides and combinations thereof in the form of particles, fibers and whiskers.

Another aspect of the present invention can be an Al-reinforced Al composite material produced according to the above method.

According to the present invention, an aluminum nitride composite material can be produced in a very short time at a temperature of 1,000 ° C or less, and therefore, it is economical and highly effective in reducing production costs.

According to the present invention, when a carbon source is used, fine AlN can be formed even at a relatively low temperature and a short production time, and the volume fraction of AlN can be easily controlled by adjusting the production conditions.

Fig. 1 shows XRD results for the composite material prepared according to Example 1 and Example 4. Fig.
2 is an SEM photograph showing the microstructure of the composite material produced according to Example 1-4.
3 is a graph showing the influence of the production time on the degree of nitriding in Examples 7 to 27;
4 shows SEM photographs and EDS analysis results of the composite material prepared according to Example 28. Fig.
5 is an SEM photograph of the composite material prepared according to Example 28 after removing the Al base.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. Furthermore, embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art. Accordingly, the shapes and sizes of the elements in the drawings may be exaggerated for clarity of description, and the elements denoted by the same reference numerals in the drawings are the same elements.

The present invention relates to a method for producing an Al-reinforced Al composite material by contacting molten Al with carbon-containing Al powder under a nitrogen atmosphere and allowing the molten Al to spontaneously infiltrate into the breathable powder bed.

In one aspect of the present invention, an air-permeable powder bed or preform comprising an Al powder and a carbon is heat-treated in a nitrogen atmosphere to nitrify the Al powder to convert it to AlN and to allow the molten Al to spontaneously penetrate into the pores of the breathable powder bed or preform (AlN-Al composite material) reinforced with AlN, characterized in that the AlN-Al composite material is solidified after solidification.

First, an air-permeable powder bed (or preform) containing Al powder and carbon can be provided (first step).

The powder bed (or preform) may comprise Al powder and carbon. The Al powder may be pure Al or Al alloy powder.

The powder bed using the Al powder may further contain Mg. When an Al alloy powder is used, the Al alloy may contain at least 0.1 wt% of Mg. The presence of Mg can promote AlN formation.

The amount of AlN formed may vary depending on the manufacturing conditions (temperature, time, nitrogen concentration, amount of Mg, presence of additional alloying elements, amount of carbon, etc.), among which the amount of carbon may have the greatest effect.

Carbon can act as a catalyst in the formation of AlN. That is, the carbon exists in a state in which the surface of the Al powder particles is uniformly coated, and the alumina oxide layer existing on the surface of the Al particles during the heating to the manufacturing temperature is removed, thereby allowing pure molten Al to be directly exposed to the surface .

In addition, carbon decomposes nitrogen gas (N ₂ ) supplied in a gaseous state into nitrogen atoms (2N), so that nitrogen atoms (N) react with Al atoms to promote AlN formation.

As the carbon, one or more selected from the group consisting of lamp carbon, acetylene carbon, carbon black, sugar, glucose, melamine, and combinations thereof can be used. AlN can be formed by using various types of carbon (such as lamp carbon, acetylene carbon, carbon black, etc.) or carbon containing compounds (such as sugar, glucose and melamine) Considering the dispersibility, it is preferable to use lamp carbon. An important consideration in carbon selection is the degree of aggregation of carbon particles.

If the carbon content is more than 10% by weight, the residual carbon may act as an impurity and cause deterioration of the physical properties of the Al-AIN composite material. Therefore, it is preferable to maintain the carbon content at 10% by weight or less.

When the average particle size of the carbon powder is too small, the carbon powders may clump together and the carbon function can not be exhibited properly. It is preferable that the carbon powder is uniformly dispersed to cover the surface of the Al powder particles uniformly.

When only carbon powder not containing Al powder is used as a powder bed, an AlN-Al composite material in which all the carbon powder (100%) is converted into AlN can be produced.

The powder bed (or the preform) may further include at least one member selected from the group consisting of oxides, carbides, borides, nitrides, and combinations thereof in the form of particles, fibers and whiskers. If such a reinforcing phase is further included, the properties of the composite material can be finely adjusted according to the reinforcing phase. For example, when an AlN-Al composite material is to be applied to a field requiring specific physical properties, a suitable strengthening phase capable of exhibiting the properties can be selected and used.

The Al powder constituting the powder bed (or the preform) may be present in a state in which all or a part of the Al powder is later converted into AlN and dispersed in the Al matrix.

The powder bed can be prepared by ball milling. Wet or dry milling. That is, the Al powder and the carbon powder may be mixed with a ceramic ball, an organic solvent, etc., and then milled to uniformly mix the Al powder and the carbon powder. This is because the function of carbon can be maximized in the process of forming AlN when the carbon powder is uniformly distributed in the Al powder.

Next, by heating in a nitrogen atmosphere, all or a part of the Al powder can be converted into AlN, and at the same time, the Al ingot can be melted and the molten Al can be spontaneously infiltrated into the void of the breathable powder bed (or the preform) Step 2).

The Al powder may be pure Al or Al alloy powder.

After the Al in the powder bed (or the preform) is changed to AlN, molten Al may penetrate into the AlN particles, and an Al-AlN composite material in which AlN particles are distributed on the Al matrix may be formed . Here, for convenience, it has been described that the Al powder in the powder bed (or the preform) is converted into AlN and the molten Al permeates into the AlN particles. However, since Al in the powder bed (or preform) changes into AlN, It is also possible to occur simultaneously. Some of the molten Al that penetrates in this process can also be converted to AlN.

The powder bed comprises Al powder and carbon powder, which may simply be in a mixed powder state, or may be a preform molded into a specific shape. The preform can be molded by putting the powder into a mold and pressing it.

The Al ingot may be a pure Al ingot or an Al alloy ingot. Al alloy ingots may contain at least 0.1 wt% Mg. The presence of Mg can further promote AlN formation.

The nitrogen atmosphere is a source of nitrogen in forming AlN. Therefore, it is preferable that the nitrogen supply is sufficient. The concentration of nitrogen may be 10-100 vol%. When the concentration of nitrogen is less than 10% by volume, the nitrogen supply is small and the AlN may not be sufficiently formed.

During the entire process of producing the composite material, the nitrogen atmosphere must be maintained so that the molten Al can penetrate into the pores of the breathable powder bed (or preform), which can be achieved by maintaining a continuous gas flow in the infiltration furnace have. The nitrogen gas flow should be sufficient to compensate for the nitrogen reduction in the atmosphere due to AlN formation in the Al matrix and sufficient to prevent the ingress of air which can oxidize the molten Al.

AlN can be formed by the following mechanism. That is, the oxide layer on the surface of the Al powder particles in the mixture is peeled off by the carbon, and Al is directly exposed to react with the nitrogen gas to form AlN. This reaction can be activated at high temperatures. The heating temperature is not particularly limited as long as the temperature at which the AlN of the mixture can be formed. The nitridation of the Al powder containing carbon can be performed at a melting point (660 ° C) or lower of Al, but it is preferably at least 700 ° C or more, more preferably 750 ° C to 1,000 ° C for spontaneous penetration of molten Al.

Next, the powdered bed (or the preform) into which molten Al is impregnated can be solidified (the third step).

When the molten Al is cooled in the pores of the powder bed (or the preform), the Al composite material can be produced in which the molten Al is known and the AlN particles are distributed (dispersed) in the Al matrix. Such Al composite material can remarkably improve mechanical properties and the like due to the AlN particles.

The carbon content, the heating temperature, the heating time, and the nitrogen flow rate have been separately described as the main factors of the formation of AlN, but they can act independently of each other, but can be related to each other. For example, when the content of Mg is the same, the heating time is shortened when the heating temperature is high, and on the contrary, if the heating temperature is low, the heating temperature may be long.

Hereinafter, the present invention will be described in detail with reference to examples.

≪ Examples 1 to 6: Influence of carbon amount >

AlN-Al composites were fabricated by the following process to investigate the effect of the amount of carbon added to the powder bed on the formation of nitrides.

First, 30 g of Al powder and 0.6 g, 1.5 g, 3 g, 4.5 g and 6 g of lamp carbon powder were put into a mixing container and shaken by hand to prepare a mixed powder.

Next, a commercially available 5083 Al ingot was cut into a size of 3 cm x 3 cm x 3 cm, put into a graphite crucible, and 1 g of Mg powder was sprinkled on the ingot. The mixture powder was filled at the injection density and the crucible was hit.

Next, the crucible was charged into a stainless steel retort, and then heated to 1,000 DEG C at a heating rate of 5 DEG C / min in a nitrogen atmosphere, and then held for 1 hour.

Nitrogen gas was supplied at a flow rate of 5,000 cc / min. In this process, molten Al spontaneously penetrates into the powder bed and an AlN-Al composite material can be formed.

After the reaction was completed, the reaction solution was cooled to room temperature while keeping the nitrogen atmosphere in order to prevent oxidation.

Table 1 shows conditions and weight increase results for each example.

The degree of nitride formation was evaluated based on the weight gain of the Al alloy / powder bed assembly. Weight gain was calculated based on the amount of powder bed. When Al is completely converted to AlN, the theoretical weight gain is 52%. In practice, however, it may be necessary to consider that there may be a partial remnant of the Al alloy placed under the assembly, and that the amount differs from one condition to another.

Al powder Lamp carbon quantity
(Ratio of Al powder) Weight increase
(Ratio of Al powder) Example 1 30 g 0 g (0 wt%) 1.37 g (4.5% by weight) Example 2 30 g 0.6 g (2% by weight) 10.15 g (33.8% by weight) Example 3 30 g 1.5 g (5% by weight) 15.17 g (50.6% by weight) Example 4 30 g 3 g (10% by weight) 18.91 g (63% by weight) Example 5 30 g 4.5 g (15% by weight) 16.24 g (54.1% by weight) Example 6 30 g 6 g (20% by weight) 11.87 g (39.5) wt%

Referring to Table 1, it can be seen that the degree of formation of AlN is greatly influenced by the amount of carbon.

Example 1 shows the case of using only Al powder without addition of carbon to the powder bed at 1,000 DEG C, and a weight increase of 4.5 wt% occurred.

Referring to Examples 2 to 6, when the amount of carbon was increased to 10 wt%, the weight increase was also increased, and when the amount of carbon was 10 wt% (Example 4), a weight increase of 63 wt% occurred.

On the other hand, when the amount of carbon is more than 10% by weight (Examples 5 and 6), it is confirmed that the nitriding is less occurred and the weight increase is decreased. Moreover, it can be confirmed that a large amount of the raw material powder remains in powder form without being completely solidified due to the excessive amount of carbon.

Therefore, in order to produce a composite material in a complete solid state, it is preferable to set the amount of carbon to 10% or less with respect to the weight of the metal powder.

In order to compare the degree of formation of AlN, XRD analysis was performed on the AlN-Al composite material, and the results are shown in FIG.

Referring to FIG. 1, it can be seen that the AlN peak was much larger when 5 wt% was added (Example 4) compared to when carbon was not added (Example 1). These results are again consistent with the results of the weight increase in Table 1.

2, the microstructure of the composite material (Example 1, Fig. 2 (A)) in which carbon was not added and the composite material The results were observed under a microscope.

Referring to FIG. 2, when carbon is not added (FIG. 2 (A)), the presence of AlN is not clearly distinguished, but when carbon is added, Al base metal and AlN are easily distinguished. That is, the microstructure of the composite material is classified into a dark gray-colored AlN region and a light gray base region. This dark gray area was identified as AlN as a result of EDS analysis. In addition, it can be seen that AlN formation was greatly increased as the amount of carbon was increased, and the result of this observation shows that the weight increase and the XRD analysis result are in good agreement.

As a result, the weight increase was about 1g when heat treated at 700 ℃ ~ 1,000 ℃ without adding carbon. From this, it can be seen that AlN is formed mainly by nitriding of Al powder by carbon powder in a nitrogen atmosphere.

≪ Examples 7 to 27: Influence of manufacturing time >

When the composites were prepared by spontaneous penetration of molten Al, the degree of formation of AlN, which is a reaction product, greatly influenced the manufacturing conditions.

Except that the amount of Al powder was increased to 40 g, and 1 g of Mg powder was sprinkled between the Al ingot and the powder bed, under the same conditions as in Examples 1 to 6.

Table 2 and FIG. 3 show the degree of AlN formation at 1,000 ° C according to the production time and the amount of lamp carbon.

Al powder Lamp carbon content time Weight gain (g) Example 7 40 g 1.2 g 3h 10.08 Example 8 40 g 1.2 g 5h 11.85 Example 9 40 g 1.2 g 7h 17.27 Example 10 40 g 2 g 1h 12.32 Example 11 40 g 2 g 3h 15.93 Example 12 40 g 2 g 5h 14.7 Example 13 40 g 2 g 7h 26.59 Example 14 40 g 2 g 10h 16.48 Example 15 40 g 2.8 g 5h 18.58 Example 16 40 g 4 g 1h 13.87 Example 17 40 g 4 g 3h 19.34 Example 18 40 g 4 g 5h 23.49 Example 19 40 g 4 g 7h 43.41 Example 20 40 g 4 g 10h 46.1 Example 21 40 g 6 g 1h 16.24 Example 22 40 g 6 g 3h 18.83 Example 23 40 g 6 g 5h 18.77 Example 24 40 g 6 g 7h 42.52 Example 25 40 g 6 g 10h 41.19 Example 26 40 g 8 g 1h 11.18 Example 27 40 g 8 g 10h 44.41

Referring to Table 2 and FIG. 3, it can be seen that as the amount of carbon is the same, the weight increase becomes larger as the time increases, thereby improving the nitrification rate.

≪ Examples 28 to 37: Influence of manufacturing temperature >

The AlN-Al composite material was produced under the same conditions as in Example 7 except that the production time was changed to 7 hours and the production temperature was changed to 827 ° C. and 1,000 ° C. in order to confirm the effect of the production temperature on the formation of AlN The conditions and results are shown in Table 3.

Al powder Lamp carbon quantity
(Ratio of Al powder) Temperature
(° C) Weight increase
(Ratio of Al powder) Example 28 40 g 0.4 g (1% by weight) 827 5.06 g (12.7% by weight) Example 29 40 g 1.2 g (3% by weight) 827 9.56 g (23.9% by weight) Example 30 40 g 1.2 g (3% by weight) 1000 17.27 g (43.2% by weight) Example 31 40 g 2 g (5% by weight) 827 11.67 g (29.2% by weight) Example 32 40 g 2 g (5% by weight) 1000 26.59 g (66.5% by weight) Example 33 40 g 2.8 g (7% by weight) 827 14.89 g (37.2% by weight) Example 34 40 g 4 g (10% by weight) 827 15.46 g (39.0% by weight) Example 35 40 g 4 g (10% by weight) 1000 43.41 g (108.5% by weight) Example 36 40 g 6 g (15% by weight) 827 14.27 g (35.7% by weight) Example 37 40 g 6 g (15% by weight) 1000 42.52 g (106.3% by weight)

Referring to Table 3, when 5 wt% of carbon was added, a weight increase of about 11.67 g occurred at 827 ° C (Example 31), but increased to almost 26.59 g at 1,000 ° C, (Example 32). From these results, it can be seen that the increase of the production temperature can greatly affect the degree of AlN formation due to the self-reaction. In Example 29, it was very difficult to cut the composite material produced when 3 wt% of carbon was added. From this, it can be seen that the strength of the composite material is greatly increased by the formation of AlN even though the weight increase of 23.9 wt% (i.e., AlN formation) has occurred.

From the above results, it can be seen that when the amount of carbon is the same, the degree of nitriding increases with increasing temperature.

FIG. 4 shows a photograph of the microstructure of the composite material according to Example 28 observed by SEM and the results of EDS analysis. Referring to FIG. 4, the circular bright portion indicated by A is the portion that was originally the Al particle in the powder bed, and its shape can be clearly observed at low magnification (FIG. 4A) and high magnification (FIG. 4B) have. Referring to Fig. 4 (B), it can be seen that the surroundings of the Al particles are coated with a dark gray reaction product.

In the A region, only Al (97.52 at.%) And Mg (2.48 at.%) Were detected by EDS analysis. On the other hand, a large amount of N (45.86 at.%) And Al (45.37 at.%) As well as a small amount of oxygen (8.77 at. Therefore, it was confirmed that the reaction product formed around Al particles was AlN, with the ratio of Al and N being almost 1. These results were not presented here, but were confirmed by TEM analysis.

FIG. 5 is a photograph of the microstructure observed by SEM after removing the Al matrix from the composite material of Example 28. FIG. Referring to FIG. 5, it can be confirmed that a very fine reaction product of about 1 mu m in particle shape or wire shape is formed around Al particles. The results of the analysis were not presented here, but the reaction product was confirmed to be AlN as a result of EDS analysis.

≪ Examples 38 to 45: Influence of nitrogen gas amount >

In order to confirm the effect of the amount of nitrogen gas on the degree of nitriding, a composite material was prepared under the same conditions as in Example 7, except that the amount of nitrogen gas was changed for 7 hours at 1,000 ° C., respectively. The conditions and results are shown in Table 4.

Al powder Lamp carbon quantity
(Ratio of Al powder) Nitrogen gas
(cc / min) Weight increase
(Ratio of Al powder) Example 38 40 g 0 g (0 wt%) 2000 5.5 g (12.7% by weight) Example 39 40 g 1.2 g (3% by weight) 2000 13.71 g (34.3% by weight) Example 40 40 g 1.2 g (3% by weight) 6000 17.27 g (43.2% by weight) Example 41 40 g 2 g (5% by weight) 2000 14.68 g (36.7% by weight) Example 42 40 g 2 g (5% by weight) 6000 26.59 g (66.5% by weight) Example 43 40 g 4 g (10% by weight) 2000 31.38 g (78.5% by weight) Example 44 40 g 4 g (10% by weight) 6000 43.41 g (108.5% by weight) Example 45 40 g 6 g (15% by weight) 6000 42.52 g (106.3% by weight)

As shown in Table 4, as the amount of nitrogen gas increases, the weight increase increases greatly. From this, it can be seen that the degree of nitriding increases as the amount of nitrogen gas increases.

≪ Examples 46 to 51: Influence of Mg amount >

In order to induce spontaneous penetration of molten Al, it is necessary to use an alkaline earth metal such as Mg, Ca and Sr together with a nitrogen atmosphere. To determine the influence of Mg on the degree of AlN formation under nitrogen atmosphere,

Table 5 shows the conditions and results for each example for examining the effect of the amount of Mg sprayed between the Al ingot and the powder bed in the crucible on the nitriding. The powder bed was fixed with 40 g of Al and 2 g of lamp carbon, and a 5083 Al ingot was used. The amount of Mg poured between the Al ingot and the powder bed was changed to 0 g, 0.3 g, 0.5 g, 0.7 g, 1.2 g, and 2 g. And the mixture was heated at 1,000 DEG C for 5 hours under a nitrogen atmosphere (6000 cc / min) to prepare a composite material.

Al powder Lamp carbon Mg
(g) Temperature time nitrogen Weight increase Example 46 40 g 2 g 0 g 1000 5h 6000 4.67 g Example 47 40 g 2 g 0.3 g 1000 5h 6000 11.68 g Example 48 40 g 2 g 0.5 g 1000 5h 6000 16.02 g Example 49 40 g 2 g 0.7 g 1000 5h 6000 11.26 g Example 50 40 g 2 g 1.5 g 1000 5h 6000 13 g Example 51 40 g 2 g 2 g 1000 5h 6000 12.57 g

Referring to Table 5, penetration occurred even when Mg was not sprinkled between the Al ingot and the powder bed (Example 46), and the amount of Mg may affect the weight increase of the composite material, (Temperature, time, nitrogen gas atmosphere, etc.).

However, Mg sprinkled between the Al ingot and the powder bed diffuses into the matrix during the production of the composite material, which can change the composition of the matrix and form undesirable reaction products (such as MgO or MgAl ₂ O ₄ ) , It is desirable to reduce the amount of Mg as much as possible in order to achieve accurate matrix composition control and good interfacial properties.

Examples 52 to 60: Influence of relative position of Mg (in the powder bed)

The effect of alkaline earth metal (Mg, Ca, Sr) on the spontaneous penetration and nitridation of molten Al can be affected by the relative position of the alkaline earth metal during the production of the composite material. On the degree of nitrification. That is, the case of adding Mg to the powder bed and the case of not adding Mg to the powder bed.

The powder bed was fixed with 40 g of Al and 2 g of lamp carbon, and a 5083 Al ingot was used. The amount of Mg sprinkled between the Al ingot and the powder bed was also fixed to 1 g. The amount of Mg added to the powder bed was fixed at 2 g, and the degree of nitridation according to the amount of carbon was compared. The composites were also prepared by heating them at 1,000 ℃ for 5 hours under a nitrogen atmosphere (6,000 cc / min).

Al powder Lamp carbon quantity
(Ratio of Al powder) Mg
(g) Weight increase
Example 52 40 g 0.4 g (1% by weight) 2 24.1 g Example 53 40 g 1.2 g (3% by weight) 0 11.85 g Example 54 40 g 1.2 g (3% by weight) 2 46 g Example 55 40 g 2 g (5% by weight) 0 14.7 g Example 56 40 g 2 g (5% by weight) 2 57.8 g Example 57 40 g 2.8 g (7% by weight) 0 18.58 g Example 58 40 g 4 g (10% by weight) 0 23.49 g Example 59 40 g 4 g (10% by weight) 2 57.8 g Example 60 40 g 6 g (15% by weight) 0 18.77 g

Referring to Table 6, it can be confirmed that the degree of nitriding increases when Mg is added to the powder bed until the amount of carbon is 10 wt%. Thus, it was found that adding Mg to the powder bed could favor the formation of AlN until the amount of carbon was 10 wt%.

Examples 61 to 62: Influence of relative position of Mg (in Al ingot)

Mg may be present inside the Al alloy or the Al ingot itself. Since the amount of Mg contained differs depending on the kind of Al alloy, it was confirmed by using other kinds of commercial Al.

The amount of Mg poured between the Al ingot and the powder bed was 2 g for 1050 Al and 1 g for 5083 Al and the composite material was prepared by heating at 827 ° C for 5 hours under a nitrogen atmosphere (6000 cc / min). The results are shown in Table 7.

Al alloy Al alloy weight Powder bed composition Powder bed volume Weight increase Example 61 1050 203.4 g Al +
3 wt% carbon 154.1 g 9.1 g Example 62 5083 148.7 g Al +
1 wt% carbon 75.8 g 62.4 g

Referring to Table 7, when 1050, 5083, 6061, and 7075 Al alloys were used irrespective of the type of alloy (that is, the difference in the amount of Mg), spontaneous penetration occurred to produce a composite material.

≪ Examples 63 to 76: Influence of relative position of Al alloy (ingot) and powder bed >

All of the foregoing embodiments are cases where a powder bed is placed on an Al ingot and a composite material is produced. This arrangement is referred to as "A placement ". On the contrary, Al ingots may be placed on the powder bed, and this arrangement is referred to as "B placement ". The composite material was prepared according to the relative positions of the Al ingot and the powder bed, and the conditions and the results are shown in Table 8.

Al
alloy Powder bed composition (g) (G) between the powder bed and the Al alloy, Produce
Temperature Produce
time weight
increase arrangement Example 63 5083 Al (30) 1.5 Mg 1000 ℃ 1 h 4.5 g A Example 64 5083 Al (30) 1.5 Mg 1000 ℃ 1 h 2.2 g B Example 65 5083 Al (30) + LC (0.6) 1.5 Mg 1000 ℃ 1 h 33.8 g A Example 66 5083 Al (30) + LC (0.6) 1.5 Mg 1000 ℃ 1 h 16.9 g B Example 67 5083 Al (30) + LC (1.5) 1.5 Mg 1000 ℃ 1 h 50.5 g A Example 68 5083 Al (30) + LC (1.5) 1.5 Mg 1000 ℃ 1 h 22.2 g B Example 69 5083 Al (30) + LC (3) 1.5 Mg 1000 ℃ 1 h 63 g A Example 70 5083 Al (30) + LC (3) 1.5 Mg 1000 ℃ 1 h 34.1 g B Example 71 5083 Al (30) + LC (4) 1 Mg 1000 ℃ 5 h 58 g A Example 72 5083 Al (30) + LC (4) 1 Mg 1000 ℃ 5 h 21 g B Example 73 5083 Al (30) + LC (1.2) 1 Mg 1000 ℃ 5 h 29.6 g A Example 74 5083 Al (30) + LC (1.2) 1 Mg 1000 ℃ 5 h 14.1 g B Example 75 5083 Al (40) 1 Mg 1000 ℃ 7 h 13.8 g A Example 76 5083 Al (40) 1 Mg 1000 ℃ 7 h 10.9 g B

# LC: lamp carbon

Referring to Table 8, it can be seen that under the same conditions, the A batch is larger by about two times than the B batch, which shows that the A batch is more effective for AlN formation.

The terms used in the present invention are intended to illustrate specific embodiments and are not intended to limit the invention. It is to be understood that the phrase " comprises " or " having " is intended to encompass a feature, a number, a step, an operation, It means that something exists, not to exclude it.

The present invention is not limited to the above-described embodiments and the accompanying drawings, but is intended to be limited only by the appended claims. It will be apparent to those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. something to do.

Claims (10)

Heat-treating the air-permeable powder bed or the preformed body containing Al powder and carbon in a nitrogen atmosphere to nitridize the Al powder to AlN, spontaneously infiltrate the molten Al into the air-permeable powder bed or pores of the preform, , And the carbon is included in an amount of 2 to 5 parts by weight based on 100 parts by weight of the Al powder.
The method according to claim 1,
Wherein the Al powder comprises pure Al powder or Al alloy powder.
The method according to claim 1,
Wherein the molten Al is a pure Al ingot or an Al alloy ingot is melted.
The method according to claim 1,
Wherein the nitrogen atmosphere has a nitrogen concentration of 10 to 100% by volume.
The method according to claim 1,
Wherein the heat treatment is performed at 700 ° C to 1,000 ° C.
3. The method of claim 2,
Wherein the Al alloy powder comprises Mg. ≪ RTI ID = 0.0 > 11. < / RTI >
The method of claim 3,
Wherein the Al alloy ingot comprises Mg. ≪ RTI ID = 0.0 > 11. < / RTI >
The method according to claim 1,
Wherein the carbon comprises at least one selected from the group consisting of lamp carbon, acetylene carbon, sugar, glucose, melamine, and combinations thereof.
The method according to claim 1,
Wherein the powder bed or the preform comprises at least one selected from the group consisting of oxides, carbides, borides, nitrides, and combinations thereof in the form of particles, fibers and whiskers. A method for manufacturing a composite material.
An Al-reinforced Al composite material produced by any one of claims 1 to 9.

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