KR20010087656A - Aluminum-based single quasicrystalline alloys - Google Patents

Abstract

PURPOSE: An alloy system is provided which can manufactures several Kg of quasicrystalline single phase aluminum alloy even by an ordinary casting method such as die casting. CONSTITUTION: In an aluminum alloy containing nickel and cobalt, the quasicrystalline single phase aluminum alloy is characterized in that silicon is added as a fourth element, wherein the quasicrystalline single phase aluminum alloy comprises 12 to 15 at.% of nickel, 13 to 16 at.% of copper, and 3 to 5 at.% of silicon which is added to the aluminum alloy containing nickel and copper, and wherein the quasicrystalline single phase aluminum alloy is manufactured by the die casting method.

Description

Aluminum-based single quasicrystalline alloys

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semicrystalline single phase aluminum alloy, and more particularly, to a semicrystalline single phase aluminum alloy prepared by a die casting method by adding silicon to an aluminum-nickel-cobalt based alloy.

Since the first quasicrystalline phase with quasi-periodic crystal structure was first discovered in 1984 in quench-solidified Al-Mn alloys, most quasi-crystalline alloys found so far have five symmetrical quasi-crystalline phases, depending on the crystal structure they possess. quasicrystalline phase and ten symmetrical quasicrystalline phase. In addition, although it is made of a metal element, it has high electrical resistance, heat shielding properties, and abrasion resistance comparable to that of a ceramic material, thereby overcoming the limitations of existing materials and having great potential in its application range.

In the quasi-crystalline alloys developed to date, quench-solidified Al-Mn alloys have a lot of limitations in practical applications because quasi-crystals are thermodynamically unstable and require very high solidification rates. However, Al-Cu-TM (TM: transition element = Fe, Ru or Os), Al-Pd-TM (TM: transition element = Mn or Re), Al-Cu-TM (TM: transition element = Co or Ni) Ternary alloys, such as Al-Ni-Co and the like, have been suggested to be used as industrial materials by forming a quasi-crystalline phase of a 5 times or 10 times symmetric structure, which is a thermodynamically stable structure by a conventional casting method. .

As a specific example, U. S. Patent No. 5433978 discloses the preparation of Al-Cu-Fe semicrystalline alloy powder. The Al-Cu-Fe alloy is heated to a high temperature in a crucible and atomized using a high pressure inert gas at 400 psi to 1500 psi to prepare a spherical alloy powder. The alloy powder includes a quasi-crystalline phase. The alloy powder can be plasma sprayed to form a coating or to strengthen it to be used as a production material.

U.S. Patent No. 5832826 discloses a precipitation hardened metal alloy, which is based on the precipitation of particles having a semi-crystalline structure, which has a aging time of up to 1000 hours and a structure maintained mainly in a tempering treatment of up to 650 ° C. A reinforcing alloy, characterized by reinforcement with an increase in tensile strength of at least 200 MPa.

US Patent No. 5419789 discloses aluminum alloys having quasicrystals. Aluminum alloys having two transition metal contents of 0.1 atomic to 25 atomic weight have a structure in which semi-crystals are uniformly distributed on aluminum or supersaturated aluminum matrix. The quasi-crystal is a 5 symmetric semi-crystalline phase or a mixed phase of the 5 symmetric semi-crystalline phase and the 10 symmetric semi-crystalline phase and has a volume fraction of less than 20. This alloy has the general formula Al _bal Ni _a X _b or Al _bal Ni _a X _b M _c (where X is at least one element selected from Fe, Co and M is 1 selected from Cr, Mn, Nb, Mo, Ta, W) And a, b and c each have an amount represented by atomic weight of 5 ≦ a ≦ 10; 0.5 ≦ b ≦ 10 and 0.1 ≦ c ≦ 5). Such aluminum alloys are disclosed to have high hardness, high strength and high thermal resistance at room temperature and high temperature.

However, the semi-crystalline alloy as described above can obtain a thermodynamically stable five- or ten-time symmetric structure semicrystalline phase, but the quasi-crystalline single phase alloy was unsuccessful because the quasi-crystalline phase is formed by the crystal reaction by the conventional casting method. Therefore, in order to obtain a single phase alloy, a long time heat treatment after casting was required. It is possible to produce quasi-crystalline single alloys by single crystal growth methods such as Czochralski method and Bridgeman method, but up to several g alloys can be obtained and solidify at a very slow speed, which limits the industrial applications such as the long time required for alloy production. have.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an alloy system capable of producing a few Kg of semi-crystalline single phase aluminum alloy even by a conventional casting method such as a die casting method.

1 to 4 relates to the present invention

1 is a result of (a) arc melting method (b) mold casting method as a result of analyzing the quasi-crystalline phase of each aluminum alloy using an X-ray diffractometer.

FIG. 2 shows the analysis of quasi-crystalline phases of the respective aluminum alloys using a scanning microscope, in which (a) arc melting method (b) mold casting method is performed.

3 is a result of analyzing a cavity surface of an aluminum alloy prepared by a die casting method using a scanning microscope (a) a high magnification scanning electron microscope image (b) a low magnification scanning electron microscope image

FIG. 4 is a case of (a) ten symmetry axis zones and (b) two symmetry axis zones as a result of analyzing a quasi-crystalline phase of an aluminum alloy prepared by a die casting method using a transmission microscope.

The present invention which can achieve the above object is characterized in that it is made by adding silicon as a fourth element in an aluminum alloy containing nickel and cobalt.

At this time, a semi-crystalline single phase was added to the aluminum alloy containing 12-15 atomic mass of nickel and 13-16 atomic mass of copper by adding 3-5 masses of silicon as a fourth element and cooling rate 10 ^{0-10 2} K / sec. It is characterized in that the alloy is produced.

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

An aluminum alloy (Al ₇₀ Ni ₁₃ Co ₁₃ Si ₄ ) containing 70 atomic weight of aluminum, 13 atomic weight of nickel, 13 atomic weight of copper, and 4 atomic weight of silicon was prepared by the following two methods. In other words, in order to obtain a relatively high cooling rate, a method of quenching 20 g of alloying elements in an argon gas atmosphere and then quenching them in a water-cooled copper mold (hereinafter referred to as "arc dissolution method") and 1.2 Kg to obtain a relatively slow cooling rate. Was prepared by a method of injecting into a steel mold preheated to about 200 ^° C. after high frequency melting in an argon gas atmosphere (hereinafter referred to as " mold casting method ").

Figure 1 shows the results of the analysis of the quasi-crystalline phase of each aluminum alloy prepared according to the test method using an X-ray diffractometer, (a) is an aluminum alloy of the arc melting method, (b) is a mold casting method Results for aluminum alloys.

From the results of FIG. 1, it can be seen that in the aluminum alloy of the mold casting method with a relatively low cooling rate, a single phase quasi-crystal was formed. On the other hand, in the case of the aluminum alloy of the arc dissolving method, which has a relatively fast cooling rate, most of them are composed of quasi-crystalline phase, but it can be seen that a small amount of gamma (γ) phase is present in the alloy together.

As shown in FIG. 2, the results of analyzing each aluminum alloy as described above using a scanning electron microscope are intended to observe backscattered electron images.

From the results of FIG. 2, it can be seen that the aluminum alloy of the die casting method is composed of ten symmetrical semi-crystalline single phases, and in the case of the arc melting method, the solidification of the symmetrical ten crystalline semi-crystalline phases and the second phase solidified into a superfine phase It can be seen that the gamma (γ) phase has a microstructure present together.

In the case of the aluminum alloy of the die casting method, the symmetric structure quasi-crystalline phase was formed into the primary solidification phase 10 times during solidification. One important point here is that in the aluminum-nickel-cobalt-based alloy, the quasi-crystal was formed by the crystallization reaction, but by adding silicon, the quasi-crystalline phase was formed into the primary solidified phase. It can be seen that it is possible to obtain an alloy. It is preferable to add silicon in 3-5 atomic weights. If the silicon content is less than 3 atomic weights, it has a microstructure in which a gamma (γ) phase coagulated into a second phase is present in addition to the quasi-crystalline phase, and the silicon content exceeds 5 atomic weights. In this case, the solidification behavior in which the 10 symmetric structure quasi-crystalline phase is crystallized as the primary crystal is changed, so the silicon content is limited to the range of 3-5 atomic weights.

Figure 3 shows the results of analyzing the surface of the cavity (cavity) formed during the solidification of the aluminum alloy manufactured by the die casting method using a scanning electron microscope, to examine the secondary electron image.

From the results of FIG. 3, the aluminum alloy of the die casting method shows the growth phenomenon of decaprism-shaped grains having 10 symmetrical structures. The quasi-crystalline phases are grown in the direction of the 10 symmetric axis, and the azimuth relationship between the grains is disordered. It can be seen that the growth in the direction.

Figure 4 shows the results of analyzing the aluminum alloy prepared by the die casting method using a transmission microscope to look at the limited field electron diffraction diagram.

4 (a) is 10 times symmetrical, (b) is a 2 times symmetrical diffraction diagram, it can be seen that the aluminum alloy of the die casting method has a 10 times symmetric quasi-crystal structure.

From the above results, it can be seen that by adding silicon to the aluminum-nickel-cobalt-based alloy, a semi-crystalline single phase aluminum alloy can be produced by a conventional mold casting method having a cooling rate of 10 ⁰ -10 ² K / sec. .

If the present invention will be described in detail based on the Examples as follows, the present invention is not limited to the Examples.

Examples and Comparative Examples

Example 1

In order to obtain a relatively slow cooling rate of an aluminum alloy (Al ₇₀ Ni ₁₃ Co ₁₃ Si ₄ ) containing 70 atomic weight of aluminum, 13 atomic weight of nickel, 13 atomic weight of copper, and 4 atomic weight of silicon, 1.2 Kg of alloying elements were dissolved in an argon gas atmosphere at high frequency. It was prepared by a mold casting method that is injected into a steel mold preheated to about 200 ^° C.

Comparative Example 1

An aluminum alloy containing 70 atomic weight of aluminum, 14 atomic weight of nickel, 14 atomic weight of copper, and 2 atomic weight of silicon was prepared in the same manner as in Example 1.

Comparative Example 2

Arc melting method in which aluminum alloy containing 70 atomic weight of aluminum, 13 atomic weight of copper, 13 atomic weight of copper, and 4 atomic weight of silicon is quenched in water-cooled copper mold after arc melting of 20g alloy element under argon gas atmosphere to obtain a relatively high cooling rate. It was prepared by.

Comparative Example 3

An aluminum alloy containing 70 atomic weight of aluminum, 15 atomic weight of nickel, and 15 atomic weight of copper was prepared in the same manner as in Comparative Example 2, and then homogenized for 48 hours under the melting temperature. The presence of a single phase can be more accurately identified.

Comparative Example 4

An aluminum alloy containing 60 atomic weight of aluminum, 20 atomic weight of nickel, and 20 atomic weight of copper was prepared in the same manner as in Comparative Example 3.

For each aluminum alloy produced by the above method was confirmed the presence phase, the results are shown in Table 1.

Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Alloy composition (atomic weight) nickel 13 14 13 15 20 cobalt 13 14 13 15 20 silicon 4 2 4 - - aluminum 70 70 70 70 60 Produce Mold casting method Mold casting method Arc dissolution method Arc dissolution method + homogenization treatment Arc dissolution method + homogenization treatment Presence 10 symmetric structural semi-decision 10 symmetric structural quasi-crystalline phase + gamma (γ) phase 10 symmetric structural quasi-crystalline phase + gamma (γ) phase 10 symmetric structural quasi-crystalline phase + gamma (γ) phase 10 symmetric structural quasi-crystalline phase + beta (β) phase

From the results of Table 1, in the case of the mold casting method of Example 1, there is a single phase semi-crystal, and when the silicon of Comparative Example 1 is manufactured by the die casting method containing less than 3 atomic weights, most of them are composed of semi-crystalline phase. It can be seen that the gamma (γ) phase of is present in the alloy together. In the case of Comparative Example 2, the aluminum alloy of the same composition as in Example 1 was manufactured by the arc dissolving method, and most of them were composed of quasi-crystalline phases, but a small amount of gamma (γ) phase was present in the alloy together, and without the addition of silicon, In Comparative Example 3 and Comparative Example 4 prepared by the dissolution method, most of them are composed of semi-crystalline phases, but it can be seen that a small amount of the second coagulation phase such as gamma (γ) phase and beta (β) phase exist in the alloy together.

From the above results, in the aluminum alloy containing nickel and cobalt, by adding silicon as the fourth element, a semi-crystalline single phase aluminum alloy can be produced by a conventional mold casting method having a cooling rate of 10 ⁰ -10 ² K / sec or less. It can be seen that.

As described above, a single-phase quasi-crystalline Al-Ni-Co-Si alloy formed by adding silicon to an aluminum alloy containing nickel and cobalt can be prepared by a conventional mold casting method. As the alloy can be manufactured, a semi-crystalline single phase powder can be prepared by an alloy grinding-powder manufacturing process, and there is an effect of replacing a conventional gas atomizing process for powder production.

Using this powder, it can be used to manufacture quasi-crystalline particulate reinforced composites using metal and polymer materials as base alloys, which can be used as high-strength, high toughness materials for high temperature. In addition, the semi-crystal sintered composite can be prepared using the powder using a high pressure molding method, and this material can be utilized as an excellent functional material such as wear resistance and corrosion characteristics.

Claims (3)

The aluminum alloy containing nickel and cobalt WHEREIN: The semi-crystal single phase aluminum alloy which consists of adding silicon as a 4th element. The method of claim 1, A semi-crystalline single-phase aluminum alloy, wherein silicon is added in an amount of 3-5 atomic weights to the aluminum alloy containing nickel 12-15 atomic weight and copper 13-16 atomic weight. The method of claim 1, Said semi-crystalline single phase aluminum alloy is manufactured by a die casting method.