WO2022139007A1 - Aluminum alloy for high-toughness casting and manufacturing method therefor - Google Patents

Abstract

The present invention relates to an aluminum alloy for casting and a manufacturing method therefor, and in a technique for manufacturing an aluminum alloy for high-toughness casting, silicon (Si), a rare earth element and the like are added to an aluminum alloy to improve strength, toughness, corrosion resistance and releasability while maintaining the flowability of an alloy for casting. Specifically, disclosed are: an aluminum alloy that is superior to AC4A- and ALDC3-based alloys, which are aluminum for casting; and a manufacturing method therefor. The aluminum alloy of the present invention comprises 8.0-11.5 wt% of silicon (Si), 0.10-0.60 wt% of magnesium (Mg), 0.0001-0.80 wt% of manganese (Mn), 0.0001-0.60 wt% of copper (Cu), 0.0001-0.50 wt% of zinc (Zn), 1.3 wt% or less of iron (Fe), 0.3 wt% or less of titanium (Ti), and a rare earth element such as cerium (Ce) and lanthanum (La).

Description

Aluminum alloy for high toughness casting and manufacturing method thereof

The present invention relates to an aluminum alloy for casting with high toughness, and more specifically, by adding silicon (Si) and rare earth elements to the alloy for casting, while maintaining the fluidity of the alloy for casting, strength, toughness, corrosion resistance and releasability are improved. It relates to an aluminum alloy for casting of high toughness and a method for manufacturing the same.

The alloy for aluminum casting is indicated by the sign of AC (Aluminum Casting), and the alloy for die casting is indicated by the sign of ALDC (Aluminum Die Casting) and is widely used.

When aging heat treatment is performed after casting for AC series, the tensile strength is high in the range of 300 MPa to 400 MPa, but the elongation is mostly in the range of about 1%, so the toughness is extremely insufficient. The ADLC series has a tensile strength in the range of 200 MPa to 300 MPa, and the elongation is mostly about 3% or less, so it also lacks toughness.

Currently, there are three types of Al-Si-Mg-based alloys widely used as alloys for aluminum die casting.

Alloy AC4A alloy for casting, which has a composition similar to ALDC 3, is also widely used.

When the toughness of the alloy is small, the alloy is easily fractured when an impact is applied to the structure. In general, since toughness and elongation are in a proportional relationship, elongation can be used as a simple indicator of toughness.

In addition, when a crack or stress corrosion crack occurs due to local corrosion on the surface of the aluminum alloy, the stress is concentrated in the crack or crack and the alloy is easily destroyed, so corrosion resistance of the aluminum alloy is also important. On the other hand, since releasability with a mold is also important for aluminum casting in a casting or die casting process, releasability is also one of important characteristics in an aluminum alloy for casting.

Therefore, there is a continuous need for an aluminum alloy for casting that has a tensile strength of 300 MPa or more, and has excellent toughness, elongation, corrosion resistance, castability and releasability.

As commercial alloys, there are alloys as shown in [Table 1] below according to the KS standard.

commercial alloy

type

Composition (wt%)

Cu

Si

Mg

Zn

Fe

Mn

Ni

Sn

Pb

Ti

Cr

Al

ALDC3

0.6 or less

9.0~ 11.0

0.4 to 0.6

0.5 below

1.3 below

0.3 below

0.5 below

0.1 below

0.15 below

0.3 below

-

Remainder

AC4A

0.25 or less

8.0~ 10.0

0.3 to 0.6

0.25 below

0.55 below

0.3 to 0.6

0.1 below

0.05 below

0.10 below

0.2 below

0.15 or less

Remainder

The Patent Document 1 is referred to as Prior Art 1 from now on, and the contents are as follows. This prior art 1 is a patent document whose rights have expired due to the expiration of the duration. The content of the aluminum alloy composition is 9.5 to 11.5 wt% of silicon (Si), 0.1 to 0.5 wt% of magnesium (Mg), 0.5 to 0.8 wt% of manganese (Mn), 30 to 300 ppm of strontium (Sr), and 0.05 It consists of ~0.3wt% of zirconium (Zr), additionally 0.15wt% or less of iron (Fe), 0.03wt% or less of copper (Cu), 0.10wt% or less of zinc (Zn) and 0.15wt% or less of titanium (Ti) include

The above prior art 1 is an improved alloy of commercial alloys ALDC3 and AC4A. It was applied for in 1995, and although its duration has expired, it has made a partial contribution to the field of aluminum alloy for casting, and has increased the tensile strength to more than 300 MPa while maintaining castability. However, the ductility was somewhat sacrificed, and the corrosion resistance was not improved. In particular, the commercial alloy and prior art 1 lack a lot of releasability with the mold after casting the mold.

Therefore, the need for improvement of ductility, corrosion resistance and releasability is in a state of great demand. Since then, various modified aluminum alloys have appeared based on the alloy composition, but research and development on alloys that simultaneously satisfy strength, ductility, corrosion resistance, castability, and releasability are continuing.

In the case of Patent Document 2 and Patent Document 3, the composition is a document in which the composition is continuously modified based on the commercial alloy and prior art 1. Patent Document 2 has a purpose of sacrificing strength and increasing ductility based on the prior art 1. That is, by reducing the content of magnesium (Mg), the aging hardening effect is abandoned to increase the ductility.

The present invention relates to an aluminum alloy more improved based on the commercial alloys ALDC3 and AC4A and the above prior art 1, and by adding rare earth metals such as cerium (Ce) or lanthanum (La), corrosion resistance and mold release properties are greatly improved. There is a big difference in that the strength and toughness were improved by adding zirconium (Zr) to the alloy in the form of fine nano-sized particles.

An object of the present invention for the above problems is to solve all the problems described above in relation to the aluminum alloy for casting and die casting. SUMMARY OF THE INVENTION An object of the present invention is to provide an aluminum alloy composition for casting or die casting having high toughness with high strength, ductility, corrosion resistance, castability and releasability, and a method for manufacturing the same.

The configuration of the present invention for achieving the above object is,

An aluminum alloy for casting, comprising:

8.0 to 11.5 wt% of silicon (Si); 0.10-0.60 wt% of magnesium (Mg); 0.0001 to 0.80 wt% of manganese (Mn); 0.0001 to 0.60 wt% of copper (Cu); 0.0001 to 0.50 wt% of zinc (Zn); 1.3 wt% or less of iron (Fe); 0.30 wt% or less of titanium (Ti); The content of any one of rare earth metals having atomic numbers 57 (La) to 71 (Lu) or a combination thereof, including lanthanum (La) and cerium (Ce), is in the range of 0.0001 to 3.0 wt%; The remainder provides an aluminum alloy for casting with high toughness, characterized in that it contains; aluminum (Al) and unavoidable impurities.

In order to manufacture the aluminum alloy according to the present invention configured as described above, the aluminum alloy is rapidly cooled after heat treatment at 350 to 550° C. for 1 hour to 10 hours, and then aging heat treatment is performed again at 100 to 200° C. for 1 hour to 10 hours. It is characterized in that it is manufactured.

In the configuration of the present invention described above,

Although the aluminum alloy was comprehensively limited in the content of silcone (Si), more specifically, it would be preferable to select one from 8.0 to 10.0 wt%, 9.0 to 11.0 wt%, or 9.50 to 11.50 wt%.

In addition, although the content of magnesium (Mg) is limited in the aluminum alloy, it will be preferable to select one from 0.30 to 0.60 wt%, 0.40 to 0.60 wt%, or 0.10 to 0.50 wt%.

Likewise, the Mn content of the aluminum alloy is preferably selected from among 0.30 to 0.60 wt%, 0.0001 to 0.30 wt%, or 0.50 to 0.80 wt%.

In addition, it is preferable to select one of 0.0001 to 0.25 wt%, 0.0001 to 0.60 wt%, or 0.0001 to 0.030 wt% of Cu in the aluminum alloy.

It is preferable to select one of 0.0001-0.25wt%, 0.0001-0.50wt%, or 0.0001-0.10wt% of Zn in the aluminum alloy.

It is preferable to select the composition in which the content of Fe in the aluminum alloy is 0.55 wt% or less or 0.15 wt% or less.

The aluminum alloy is preferably composed by selecting the Ti content in the range of 0.20 wt% or less or 0.15 wt% or less.

The aluminum alloy preferably has a content of cerium (Ce) in the range of 0.05 to 1.5 wt%.

In the aluminum alloy, the content of lanthanum (La) is preferably in the range of 0.05 to 1.5 wt%.

The aluminum alloy is characterized in that it further comprises strontium (Sr) selected from the range of 0.0001 to 0.045 wt%, 0.003 to 0.030 wt%, or 0.005 to 0.015 wt%, based on the total weight.

The aluminum alloy is an aluminum alloy for high toughness casting, characterized in that it further comprises zirconium (Zr) selected within the range of 0.0001 to 0.30 wt% or 0.05 to 0.30 wt% based on the total weight.

The aluminum alloy is characterized in that the phosphorus (P) component is further added in the form of any one of gallium phosphide, indium phosphide, or a combination thereof, in a weight ratio of 0.0001 to 0.0250 wt% or 0.0001 to 0.0030 wt%.

The aluminum alloy preferably further comprises 0.0001 to 0.50 wt% or 0.05 to 0.50 wt% of molybdenum (Mo).

On the other hand, the aluminum alloy of the present invention is one selected from Cr, V, Ni, In, Pb, Bi, Ca, Na, P, B, Ag, Pd, Sb, Sc, Nb, Co, Mo, Be, Hf or Y By further comprising more than one species, an aluminum alloy for high toughness casting can be manufactured.

The aluminum alloy is in the range of 0.0001 to 0.50 wt% ZrO ₂ , SiO ₂ , Al ₂ O ₃ , Y ₂ O ₃ CeO ₂ , La ₂ O ₃ Or further comprising any one of a combination thereof, characterized in that the oxide is uniformly dispersed in the state of nano-sized particles in the alloy. In this configuration, ZrO ₂ , SiO ₂ , Al ₂ O ₃ , Y ₂ O ₃ , CeO ₂ , La ₂ O ₃ Or any one of these combinations is characterized in that the master alloy of aluminum and oxide is made and the master alloy is put into the molten metal.

The present invention is basically an improvement of ALDC3, AC4A and prior art 1, and in particular, by adding rare earth elements such as cerium (Ce) and lanthanum (La), corrosion resistance and releasability are greatly improved. In addition, the strength and toughness can be improved by adding zirconium (Zr) in the form of fine nano-sized particles. Due to this, it is possible to greatly expand the applications of aluminum alloys for casting or die casting.

1 is a characteristic graph of measuring mechanical properties among data measuring tensile strength, yield strength, elongation, hardness, corrosion resistance, and releasability of an alloy according to the present invention;

Hereinafter, an aluminum alloy composition according to the present invention and a manufacturing process thereof will be described. Since the embodiments described in this specification are only the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention, there may be various equivalents and modifications that can be substituted for them at the time of the present application. should understand On the other hand, the content indication in the present invention is a ratio with respect to the total weight of the aluminum alloy. All content indications in the description and claims of the present invention are also the same.

In the case of composition development of metal alloys, it is a well-known fact that, even if the composition of alloy elements changes by 0.005%, significant changes occur in physical properties due to the specificity of the alloy technology field.

Since there are as many types of alloying elements as there are types of metals on the periodic table, numerous combinations can occur in the development of alloy compositions. Therefore, even minute changes in the type and composition of alloy elements can significantly improve the properties of the new alloy, so minute changes in composition and composition are very important in the field of alloy composition development.

Effect of addition of alloying elements

The main alloying elements in aluminum alloys are silicon (Si), manganese (Mn), magnesium (Mg), copper (Cu), zinc (Zn), iron (Fe), titanium (Ti), strontium (Sr), and zirconium (Zr). ), molybdenum (Mo) and rare earth elements such as cerium (Ce) and lanthanum (La) have the following effects on the properties of the alloy.

Silicon (Si)

Silicon (Si) is a major component that increases the fluidity of the alloy in the molten state during the die casting process. When an appropriate amount is added, the melting point decreases, thereby improving castability and increasing fluidity. However, when it is added excessively, the fluidity deteriorates. In addition, as the content of Si increases, it acts as an element to improve fatigue strength, hardness and wear resistance, but reduces ductility and impact resistance. When coexisting with magnesium (Mg), Mg ₂ Si may be formed to improve strength by aging treatment.

A preferred range in the present invention is 8.0 to 11.5 wt%, and a more preferred range is 8.0 to 10.0 wt% or 9.0 to 11.0 wt% or 9.5 to 11.5 wt%.

Magnesium (Mg)

Magnesium (Mg) improves mechanical strength by a solid solution effect, and aging strengthening characteristics may occur depending on the coexistence of silicon (Si) and zinc (Zn). Machinability is improved, corrosion resistance to seawater is improved, and solidification shrinkage is reduced. Weldability and surface finish properties are also improved. However, since the fluidity of the molten metal is weakened and the bond with oxygen is particularly strong, care must be taken to introduce oxides. If the content is more than an appropriate amount, the fluidity deteriorates, and if it is added more than that, die casting becomes difficult, and microbubbles are easily generated on the surface of the alloy.

A preferred range in the present invention is in the range of 0.1 to 0.5 wt%. A more preferred range is 0.30 to 0.60 wt% or 0.40 to 0.60 wt% or 0.10 to 0.50 wt%.

Manganese (Mn)

Manganese (Mn) increases the strength of the aluminum alloy. When the manganese (Mn) content is less than 0.5wt%, the effect of increasing the strength is small, there is an effect of removing the bad effect of adding iron (Fe) and the effect of refining the grains, and a compound that does not impair corrosion resistance is formed. Therefore, it is possible to improve the strength without lowering the corrosion resistance. However, an excessive amount of manganese (Mn) may lower the mechanical strength of the aluminum alloy, so care must be taken. In addition, it can cause hot spots in casting, and has the effect of increasing the releasability from the mold.

A preferred range in the present invention is 0.0001 to 0.80 wt%, and a more preferred range is 0.30 to 0.60 wt% or 0.0001 to 0.30 wt% or 0.50 to 0.80 wt%.

Copper (Cu)

Copper (Cu) is dissolved in the matrix to increase the strength of the aluminum alloy and cause an age hardening effect. When the content is less than 0.12wt%, it is difficult to show the effect of adding copper, such as corrosion resistance, and when the content exceeds 0.45wt%, both extrudability and corrosion resistance are reduced at the same time. When it exceeds the appropriate amount, fluidity will fall. It is known that when copper (Cu) is more than an appropriate content, precipitates tend to form at grain boundaries, which increases sensitivity to intergranular corrosion and local corrosion, resulting in a side effect of lowering strength. It is known to improve the resistance to stress corrosion cracking in the case of a small addition of 0.15 wt% or less.

A preferred range in the present invention is 0.0001 to 0.60 wt%, and a more preferred range is 0.0001 to 0.25 wt% or 0.0001 to 0.60 wt% or 0.0001 to 0.030 wt%.

Zinc (Zn)

Zinc (Zn) can coexist with magnesium (Mg) to improve mechanical properties and significantly improve castability. It also exhibits some effect on age hardening.

A preferred range in the present invention is 0.0001 to 0.50 wt%, and a more preferred range is 0.0001 to 0.25 wt% or 0.0001 to 0.50 wt% or 0.0001 to 0.10 wt%.

iron (Fe)

Iron (Fe) is an element that precipitates as an intermetallic compound in an aluminum alloy and improves wear resistance. If the content is less than 0.1wt%, there is almost no wear resistance effect, and if it exceeds 0.3wt%, the particles are coarsened and workability is deteriorated.

Also, an Al ₃ Fe compound is formed even in a very small amount, and since it is combined with silicon (Si) to form an Al-Fe-Si intermetallic compound, it is a factor of deterioration of mechanical properties. Even a small amount deteriorates the surface gloss and weakens corrosion resistance and ductility.

Iron (Fe) prevents sintering in the mold during the die casting process, and the amount added at this time is sufficient if it is 0.5 wt% to 1.0 wt% or less, and if it exceeds 0.5 wt%, the ductility of the alloy tends to decrease.

A preferred range in the present invention is 1.30 wt% or less. A more preferred range is 0.55 wt% or less or 0.15 wt% or less.

Titanium (Ti)

Titanium (Ti) improves mechanical properties as a particle refining element, and has an effect of preventing cracks. If it is less than 0.05 wt%, there is no effect, and if it is 0.2 wt% or more, a decrease in elongation may occur. When added excessively, there is a problem of causing brittleness, so it is preferable to be added within an appropriate range. When it exceeds 0.25 wt%, a coarse intermetallic compound is formed to reduce formability (processability).

A preferred range in the present invention is 0.30 wt% or less. A more preferred range is 0.20 wt% or less or 0.15 wt% or less.

Strontium (Sr)

Strontium (Sr), as a modifier, improves the flowability by changing the shape of the alloy structure, particularly the AlSi structure, from needle to fine spherical shape. In the past, sodium (Na) played such a role, but sodium (Na) has high oxidizing properties and acts to lower the melting point of the alloy, and is being replaced with strontium (Sr) in recent years. However, care must be taken because there is a disadvantage in that mechanical strength is lowered when excessively added. In addition, it improves the releasability in the mold.

The effect appears from the addition of 80ppm, and if it is over 350ppm, it may cause the formation of bubbles during welding, so be careful. Above 450 ppm, the elongation decreases.

A preferred range in the present invention is 0.0001 to 0.045 wt% or 0.003 to 0.030 or 0.005 to 0.015 wt%.

Zirconium (Zr)

Zirconium (Zr) exhibits precipitation hardening and grain refinement effects. If it is less than 0.05wt%, the crystal grain refinement effect is weak, and if it is more than 0.2wt%, it affects the elongation reduction.

A preferred range in the present invention is 0.0001 to 0.30 wt% or 0.05 to 0.30 wt%.

Molybdenum (Mo)

Molybdenum (Mo) is dissolved in aluminum grains to increase the strength from 0.05wt% addition. At this time, it is characterized in that the elongation is increased without a decrease in other mechanical properties. However, care must be taken because the addition of Mo increases the melting point of the alloy.

A preferred range in the present invention is in the range of 0.0001 to 0.50 wt%. A more preferable range is in the range of 0.05 to 0.50 wt%.

rare earth metal

The greatest feature of the present invention is that a rare earth metal (RE) having an atomic number of 57 (La) to 71 (Lu) containing cerium (Ce) and lanthanum (La) is added to an aluminum alloy in an appropriate amount to improve strength and It has greatly improved ductility and corrosion resistance and releasability.

Rare earth metals having atomic numbers 57 (La) to 71 (Lu), including cerium (Ce) and lanthanum (La), act to reduce local corrosion caused by precipitates deposited in a matrix. In addition, corrosion resistance is strengthened by reducing components such as iron (Fe) and nickel (Ni), which are corrosion-resistant elements present in the molten metal during aluminum production.

In addition, since the rare earth metal has an effect of increasing the corrosion potential, it is possible to minimize the addition of copper (Cu) or to replace copper (Cu). Therefore, when the copper (Cu) content is increased to increase the corrosion potential, there is an effect of minimizing these side effects, and thus the corrosion resistance is improved.

In addition, by improving the ductility and adhesion of the oxide film formed at the grain boundary or the surface, the lifetime of the oxide film is extended and corrosion resistance is improved. In addition, by increasing the strength and ductility of the aluminum alloy, the plastic workability of the metal is improved, and there is an effect of improving the brazing properties. In addition, rare earth metals increase the surface gloss by changing the alloy surface properties and increase the mold releasability.

A lot of research and development is being carried out on rare earth metals due to their beneficial properties, but development activities have been mainly focused on the field of increasing the corrosion resistance of magnesium (alloy) and the field of increasing the corrosion resistance by conversion coating on the surface of aluminum alloy.

However, in the present invention, the application field of the aluminum alloy can be expanded by adding a rare earth metal to improve corrosion resistance and releasability, which are disadvantages of the aluminum alloy for high-strength, high-toughness casting.

In the present invention, the preferred range is 0.0001 to 3.0 wt%, and more preferably, the content range of cerium (Ce), lanthanum (La), other rare earths, or a combination thereof is 0.05 to 1.5 wt%.

other elements

In all of the above cases, the aluminum alloy is an alloying element widely used in the aluminum industry (Cr, V, Ni, In, Pb, Bi, Ca, Na, P, B, Ag, Pd, Sb, Sc, Nb, Co, Mo, Be, Hf or Y) and unavoidable impurities may be further included. In particular, in the case of phosphorus (P), when the phosphorus component in the form of gallium phosphide or indium phosphide is added in the range of 1 to 250 ppm or 1 to 30 ppm, there is a grain refining effect, and in the case of boron (B), the grain refining effect is also effective. there is

In the present invention, the alloying element zirconium (Zr) may be added in the form of a metal, but may be present in the alloy in the form of a nanoparticle-sized oxide to further enhance the effect of the addition. This is one of the great features of the present invention.

When the nano-sized particles of zirconium oxide are finely distributed in the aluminum alloy, by the principle of fine particle dispersion strengthening, the movement of dislocations that appear during the deformation of the alloy within the grains is prevented, so that the strength can be improved without reducing the ductility. . In addition, when zirconium (Zr) is added to the alloy as a metal component, the ductility is reduced above a certain concentration, but when it is finely dispersed and distributed in the form of nano-particle oxides, the ductility does not decrease even at a certain amount or more, unlike the metal component. There are features that do not.

Zirconium (Zr) has a melting point of 1,855° C. and is difficult to dissolve in a general aluminum alloy manufacturing process. At this time, zirconium is present as a metal component in the alloy.

On the other hand, in order to make zirconium (Zr) exist in the form of a fine oxide in the alloy, either a nanometer-sized zirconium oxide fine powder such as ZrO ₂ is added to the aluminum molten metal, or ZrH, ZrH ₂ , ZrH ₄ In the form of a zirconium hydride powder such as ZrH 4 It can be put into aluminum molten metal. However, since it is difficult to obtain a uniform dispersion state in the method of directly inputting the molten metal, it is more efficient to prepare the Al-ZrO ₂ master alloy and then inject the master alloy into the molten metal. When preparing the master alloy, it is preferable to divide the particles into several batches and add them in small amounts so that they can be uniformly dispersed in the master alloy. Similarly SiO ₂ , Al ₂ O ₃ , Y ₂ O ₃ , CeO ₂ , La ₂ O ₃ The addition of nano-sized particles such as ZrO ₂ can produce a similar effect. At this time, the preferred range of the oxide (ZrO ₂ , SiO ₂ , Al ₂ O ₃ , Y ₂ O ₃ , CeO ₂ , La ₂ O ₃ ) is in the range of 0.0001 to 0.50 wt%.

Molybdenum (Mo) has a high melting point, so it is preferable to use an Al-Mo master alloy when added to the molten metal.

Meanwhile, in the present invention, the aluminum alloy is rapidly cooled after solution heat treatment at 350 to 550° C. for 1 hour to 10 hours, and then subjected to aging heat treatment at 100 to 200° C. for 1 hour to 10 hours to further strengthen the properties of the alloy. can do it

(Example)

For the production of the alloy according to the present invention, the temperature of the molten alloy was controlled in a temperature range of 670 to 850° C. using a crucible electric furnace, and an ingot was manufactured through casting. This ingot was mold-cast through a die-casting device, and a typical range used in aluminum die-casting was used for the process parameters at this time. T6 heat treatment was performed under normal heat treatment conditions. The alloy compositions and heat treatment conditions of Comparative Examples and Examples of the present invention are shown in Table 2.

division	Composition (wt%)											heat treatment
	Si	Mg	Mn	Cu	Zn	Fe	Ti	Sr	Zr/ZrO 2	Re	Al
comparative example
AC4A	9.5	0.50	0.50	0.10	0.10	0.10	0.05	-	-	-	Remainder	T6
Example
One	9.5	0.50	0.50	0.10	0.10	0.10	0.05	0.01	0.15	-	Remainder	-
2	9.5	0.50	0.50	0.10	0.10	0.10	0.05	0.01	0.15	Ce 0.15 La 0.15	Remainder	-
3	9.5	0.50	0.50	0.10	0.10	0.10	0.05	0.01	0.15	Ce 0.15 La 0.15	Remainder		T6
4	9.5	0.50	0.50	0.10	0.10	0.10	0.05	0.01	(ZrO 2 ) 0.15	Ce 0.15 La 0.15	Remainder	T6

※ RE (Rare Earth Element): Rare earth elements, Ce and La, etc.

Tensile strength, yield strength, elongation, hardness, corrosion resistance, and releasability of the alloy thus prepared were measured and indicated in Table 3, among which the measurement results for mechanical properties are shown in FIG.

In order to evaluate tensile strength, yield strength and elongation, a tensile test was performed according to KS standards. It was carried out according to the test method. In order to evaluate the corrosion resistance properties, SWAAT evaluation was performed according to the ASTM standard, and the results are shown in Table 3. The SWAAT evaluation was performed according to ASTM standard G85. The evaluation of releasability after die casting was evaluated in 5 steps from A (best) to E (lowest) by visually checking the degree of bubble formation, pinhole formation, and wrinkle formation after the casting was removed from the mold after casting.

division	The tensile strength (MPa)	yield strength (MPa)	elongation (%)	Hardness (HB)	corrosion resistance SWAAT Leak time (hr.)	atypia
comparative example
AC4A	240	220	2.5	90	440	D
Example
One	294	137	7.9	96	480	C
2	306	153	8.5	105	730	B
3	348	284	7.1	117	850	A
4	340	275	10.0	113	870	A

※ Releasability: A (best), B (upper), C (middle), D (lower), E (lowest)

According to Table 3, Comparative Example and Example 3 of the present invention show that although the conditions are similar, the case of the present invention is superior. Also, referring to Examples 1 to 4 of the present invention, the addition of Sr and Zr shows the effect of increasing the tensile strength, and the addition of the rare earth shows the improvement of ductility, corrosion resistance and releasability. As is well known, T6 heat treatment increases tensile strength and yield strength, but decreases ductility somewhat. When the metal zirconium is replaced with zirconium oxide, it can be seen that the ductility is improved while minimizing the decrease in strength. This trend can also be confirmed in FIG. 1 .

Claims (18)

1. In the aluminum alloy for casting,

   8.0 to 11.5 wt% of silicon (Si);

   0.10-0.60 wt% of magnesium (Mg);

   0.0001 to 0.80 wt% of manganese (Mn);

   0.0001 to 0.60 wt% of copper (Cu);

   0.0001 to 0.50 wt% of zinc (Zn);

   1.3 wt% or less of iron (Fe);

   0.30 wt% or less of titanium (Ti);

   The content of any one of rare earth metals having atomic numbers 57 (La) to 71 (Lu) including lanthanum (La) and cerium (Ce) or a combination thereof is in the range of 0.0001 to 3.0 wt%;

   The remainder is aluminum (Al) and unavoidable impurities;

   It characterized in that it comprises a, high toughness casting aluminum alloy.
2. The method of claim 1,

   The aluminum alloy is an aluminum alloy for high toughness casting, characterized in that the content of silicon (Si) is 8.0 to 10.0 wt% or 9.0 to 11.0 wt% or 9.50 to 11.50 wt%.
3. The method of claim 1,

   The aluminum alloy is an aluminum alloy for high toughness casting, characterized in that the content of magnesium (Mg) is 0.30-0.60wt% or 0.40-0.60wt% or 0.10-0.50wt%.
4. The method of claim 1,

   The aluminum alloy is an aluminum alloy for high toughness casting, characterized in that the content of manganese (Mn) is 0.30 to 0.60 wt% or 0.0001 to 0.30 wt% or 0.50 to 0.80 wt%.
5. According to claim 1,

   The aluminum alloy is an aluminum alloy for high toughness casting, characterized in that the content of copper (Cu) is 0.0001 to 0.25wt% or 0.0001 to 0.60wt% or 0.0001 to 0.030wt%.
6. According to claim 1,

   The aluminum alloy is an aluminum alloy for high toughness casting, characterized in that the content of zinc (Zn) is 0.0001 to 0.25 wt% or 0.0001 to 0.50 wt% or 0.0001 to 0.10 wt%.
7. According to claim 1,

   The aluminum alloy is an aluminum alloy for high toughness casting, characterized in that the content of iron (Fe) is in the range of 0.55 wt% or less or 0.15 wt% or less.
8. According to claim 1,

   The aluminum alloy is an aluminum alloy for high toughness casting, characterized in that the content of titanium (Ti) is in the range of 0.20 wt% or less or 0.15 wt% or less.
9. According to claim 1,

   The aluminum alloy is an aluminum alloy for high corrosion resistance casting, characterized in that the content of cerium (Ce) is in the range of 0.05 to 1.5 wt%.
10. According to claim 1,

    The aluminum alloy is an aluminum alloy for high toughness casting, characterized in that the content of lanthanum (La) is in the range of 0.05 to 1.5 wt%.
11. According to claim 1,

    The aluminum alloy is an aluminum alloy for high toughness casting, characterized in that it further comprises strontium (Sr) of 0.0001 to 0.045 wt% or 0.003 to 0.030 wt% or 0.005 to 0.015 wt%.
12. According to claim 1,

    The aluminum alloy is an aluminum alloy for high toughness casting, characterized in that it further comprises zirconium (Zr) of 0.0001 to 0.30 wt% or 0.05 to 0.30 wt%.
13. According to claim 1,

    The aluminum alloy further comprises any one of gallium phosphide (InP), indium phosphide (GaP) or a combination thereof in an amount corresponding to 0.0001 to 0.0250 wt% or 0.0001 to 0.0030 wt% of the phosphorus (P) component Characterized by, an aluminum alloy for high toughness casting.
14. According to claim 1,

    The aluminum alloy is an aluminum alloy for high toughness casting, characterized in that it further comprises 0.0001 to 0.50 wt% or 0.05 to 0.50 wt% of molybdenum (Mo).
15. According to claim 1,

    The aluminum alloy further includes at least one selected from Cr, V, Ni, In, Pb, Bi, Ca, Na, P, B, Ag, Pd, Sb, Sc, Nb, Co, Mo, Be, Hf, or Y. Characterized in that it comprises, an aluminum alloy for high toughness casting.
16. According to claim 1,

    The aluminum alloy further includes any one of ZrO ₂ , SiO ₂ , Al ₂ O ₃ , Y ₂ O _{3 ,} CeO ₂ , La ₂ O ₃ or a combination thereof in the range of 0.0001 to 0.50 wt%, and these oxides are An aluminum alloy for high toughness casting, characterized in that it is uniformly dispersed in the state of nano-sized particles in the alloy.
17. 17. The method of claim 16,

    ZrO ₂ , SiO ₂ , Al ₂ O ₃ , Y ₂ O ₃ , CeO ₂ , La ₂ O ₃ or any one of a combination thereof produces a master alloy of aluminum and its oxides, and the master alloy is added to the molten metal. Characterized in that the input, high toughness casting aluminum alloy.
18. According to claim 1,

    The aluminum alloy is rapidly cooled after heat treatment at 350 to 550° C. for 1 hour to 10 hours, and then aging heat treatment is performed again at 100 to 200° C. for 1 hour to 10 hours. manufacturing method.

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