JP4757022B2 - High strength and toughness aluminum alloy extruded material and forged material excellent in corrosion resistance, and method for producing the extruded material and forged material - Google Patents

Description

  The present invention relates to a high-strength, high-toughness aluminum alloy extruded material and forged material excellent in corrosion resistance, and a method for producing the extruded material and forged material.

  In recent years, especially in the field of transportation equipment, there has been an increasing demand for exhaust gas regulations and carbon dioxide emission suppression. To meet these demands, improvements in fuel efficiency due to weight reduction have attracted attention, and as a means to replace conventional iron-based materials. Application of aluminum materials is being studied.

  As aluminum materials for transportation equipment, 1000 series and 3000 series aluminum alloys are often used when only corrosion resistance is required, but when used in corrosive environments and high strength and high toughness are required. In many cases, a 6000 series alloy, particularly a JIS6061 alloy, having a good balance of the three characteristics of corrosion resistance, high strength, and high toughness and excellent productivity is applied.

  However, the structural member of JIS6061 alloy is manufactured by hot forging an ingot, or hot extruding the ingot, then hot forging, and then T6 tempering. When a thing is processed according to a conventional method, only a strength characteristic of about 270 to 320 MPa is obtained in tensile strength, and it is difficult to achieve a sufficient weight reduction of the vehicle structure.

  In order to solve this problem, by adding Mn, Cr, Zr positively and adjusting the amount of Mg, Si, the generation of coarse recrystallized grains can be prevented and the quenching sensitivity Al- Mg-Si alloys (see Patent Document 1) and Al-Mg-Si alloys for forging (see Patent Document 2) that increase the strength by increasing the contents of Mg, Si and Cu as main alloy components Although it has been proposed, toughness and corrosion resistance are not necessarily sufficient, and in particular, an increase in Cu causes a decrease in corrosion resistance.

For the purpose of improving toughness, aluminum alloy forgings in which the grain size and interval of crystallized substances such as Mn, Cr, and Zr are controlled have been proposed (see Patent Document 3), but the Charpy impact value obtained is at most 13 J / It is cm ² and is not sufficient for use as a high-strength undercarriage part. An aluminum alloy forging material in which the area ratio of the subgrain structure is controlled has also been proposed (see Patent Document 4). In order to ensure a Charpy impact value of 25 J / cm ² or more regardless of the forging conditions, The crystal ratio needs to be 90% or more, which is difficult in actual operation.

  When aluminum alloy materials are applied to structural members for vehicles, recyclability is an important issue from the viewpoint of cost reduction. The use of materials that greatly deviate from the range of existing standard alloy components is distinguished from other standard alloys. In general, it is not preferable from the viewpoint of recycling to increase the kind and content of the additive element, and it is necessary to consider this point for the aluminum alloy for vehicle structural members.

First, the applicants considered the above viewpoint, Si: 0.40 to 0.8%, Mg: 0.8 to 1.2%, Cu: 0.40% or less, Mn: 0.00. It is a forging material of an aluminum alloy containing 08 to 0.15%, Cr: 0.10 to 0.35%, and having a composition composed of the balance Al and unavoidable impurities. Extrusion of an Al-Mg-Si alloy characterized by the presence of a subcrystalline structure with an average crystal grain size of 10 μm or less occupying a region of 50 to 95% of a right-angle cross section in a portion other than the surface layer portion in the crystal structure A forging material was proposed (see Patent Document 5).
Japanese Patent Publication No. 5-47613 Japanese Patent Laid-Open No. 5-59477 JP 2001-107168 A JP 2004-315938 A JP 2004-68076 A

In general, in order to improve the corrosion resistance, it is necessary to make the potential of the entire material noble and not cause a potential difference inside the material, that is, not generate a local battery. The local battery is generated by the segregation of alloy elements at the grain boundaries and the formation of non-precipitation regions in the vicinity of the grain boundaries. In the case of an Al—Mg—Si based alloy, it is necessary to increase the contents of Mg ₂ Si and Cu in order to increase the strength. However, without controlling the structure, the contents of Mg ₂ Si and Cu are simply increased. If the number is increased, formation of a local battery cannot be suppressed, so that it is difficult to achieve both high strength and corrosion resistance in an Al—Mg—Si alloy.

  The inventors have studied in detail about the relationship between the alloy component, strength, and corrosion resistance in the previously proposed Al-Mg-Si-based extruded / forged material. As a result, the amount of Mg, amount of Si, and amount of Cu were determined. It has been found that by adjusting to a specific relationship and controlling the cross-sectional structure, corrosion resistance can be maintained even if the amount of Cu is increased.

The present invention has been made as a result of further testing and examination based on the above knowledge, and its purpose is to further improve the strength and toughness, that is, the proof stress, from the conventional Al-Mg-Si alloy. High strength, high toughness Al—Mg—Si based aluminum alloy extruded material excellent in corrosion resistance suitable for vehicle equipment members capable of obtaining high strength of 400 MPa or more and high toughness of Charpy impact value of 25 J / cm ² or more, and It is providing the manufacturing method of a forging material, this extrusion material, and a forging material. The aluminum alloy material can be sufficiently used as an undercarriage component in terms of strength, and can be sufficiently used even in a severe use environment in terms of corrosion resistance.

The high strength and high toughness aluminum alloy extruded material excellent in corrosion resistance according to claim 1 for achieving the above object is Si: 0.7 to 1.4% (mass%, the same applies hereinafter), Mg: 0.55 -0.95%, Cu: more than 0.43% and 1.0% or less, Mn: 0.15-0.43%, Cr: 0.05-0.23%, and Zr: 0 0.05% to 0.24%, the balance being Al and impurities, and satisfying [Si%] × 1.73- [Mg%]> [Cu%] × 1.03 An aluminum alloy extruded material obtained by solution treatment and aging treatment of a hot extruded material of an aluminum alloy having the following composition: the thickness center of the cross section of the extruded material has a subcrystalline structure having an average crystal grain size of 10 μm or less. In addition , the ratio of the subgrain structure to the cross section is 70% or more, and It has a proof stress of 400 MPa or more and a Charpy impact value of 25 J / cm ² or more .

A high strength and high toughness aluminum alloy extruded material excellent in corrosion resistance according to claim 2 is the composition of the aluminum alloy according to claim 1, wherein Mn is 0.17 to 0.43% and Cr is 0.07 to 0.00. 23% and Zr is 0.10 to 0.24%.

The method for producing a high-strength, high-toughness aluminum alloy extruded material excellent in corrosion resistance according to claim 3 is a method for producing the aluminum alloy extruded material according to claim 1 or 2 , wherein the composition according to claim 1 or 2 is used. The aluminum alloy is subjected to a hot extrusion process, followed by solution treatment at 510 to 570 ° C. and aging treatment at 150 to 200 ° C.

The method for producing a high-strength, high-toughness aluminum alloy extrudate excellent in corrosion resistance according to claim 4 is the method according to claim 3 , wherein the hot extrusion is performed at a temperature of 480 to 550 ° C. and a surface reduction rate of 30% or more. It is characterized by.

A high-strength, high-toughness aluminum alloy forged material excellent in corrosion resistance according to claim 5 is obtained by hot forging the aluminum alloy hot- pressed material having the composition according to claim 1 or 2 and subjecting it to a solution treatment and an aging treatment. The forged aluminum alloy material has a sub-grain structure with an average crystal grain size of 10 μm or less at the thickness center of the cross-section of the forged material, and the proportion of the sub-crystal grain structure in the cross-section is 70% or more. Ah it is, and characterized by having a higher yield strength and 25 J / cm ² or more Charpy impact value 400 MPa.

A method for producing a high-strength, high-toughness aluminum alloy forging material excellent in corrosion resistance according to claim 6 is a method for producing an aluminum alloy forging material according to claim 5 , wherein the forging material has the composition according to claim 1 or 2. A hot extruded material of an aluminum alloy is subjected to solution treatment at 510 to 570 ° C. after hot forging and aging treatment at 150 to 200 ° C.

According to the present invention, a vehicle capable of obtaining strength and toughness further improved from conventional Al-Mg-Si alloys, that is, high strength of 400 MPa or more in proof stress and high toughness of Charpy impact value of 25 J / cm ² or more. Provided are a high-strength, high-toughness Al—Mg—Si-based aluminum alloy extruded material and forged material excellent in corrosion resistance suitable for equipment members, and a method for producing the extruded material and forged material. The aluminum alloy material can be sufficiently used as an undercarriage component in terms of strength, and can be sufficiently used even in a severe use environment in terms of corrosion resistance.

  As a result of conducting a detailed study on the relationship between the alloy composition, strength, and corrosion resistance in the extruded material and forged material of the Al-Mg-Si alloy, the amount of Mg, the amount of Si and the amount of Cu were adjusted to a specific relationship, and the cross-sectional structure was changed. It has been found that by controlling, the corrosion resistance can be maintained even when the amount of Cu is increased, and that the potential of the material can be made nobler than pure aluminum. Specifically, by forming a subgrain structure with an average crystal grain size of 10 μm or less, segregation of alloying elements to the crystal grain boundary is suppressed, and formation of a non-precipitated region in the vicinity of the grain boundary is suppressed, thereby improving corrosion resistance. Is planned.

The significance and reasons for limitation of the alloy components in the present invention will be described. Si coexists with Mg and precipitates Mg ₂ Si particles in the matrix to improve the strength. The preferred content is in the range of 0.7 to 1.4%. If the content is less than 0.7%, sufficient strength cannot be obtained. If the content exceeds 1.4%, the workability decreases and the elongation decreases. To do. A more preferable content range of Si is 0.8 to 1.2%.

Mg functions together with Si to precipitate Mg ₂ Si particles in the matrix and improve the strength of the alloy. The preferred content is in the range of 0.55 to 0.95%, and if it is less than 0.55%, sufficient strength cannot be obtained, and if it exceeds 0.95%, workability and hardenability are deteriorated. . A more preferable content range of Mg is 0.6 to 0.9%.

  Cu functions as a solid solution in the matrix to improve the strength. The preferable content is in the range of more than 0.43% and 1.0% or less. If the content is less than 0.43%, the effect is not sufficient, and if it exceeds 1.0%, the corrosion resistance is lowered. A more preferable content range of Cu is 0.48 to 1.0%.

In the present invention, to contain Cu in an amount exceeding 0.43% and improve strength while maintaining corrosion resistance, the Si amount, Mg amount, and Cu amount are controlled to satisfy the following relational expressions. is required.
[Si wt%] × 1.73- [Mg wt%]> [Cu wt%] × 1.03
The left side is a formula that defines the amount of excess Si. As a result of conducting a corrosion resistance test using aluminum alloy extruded materials having various compositions within the scope of the present invention, the value of this formula is set to 1.03 times the Cu amount or more. It was found that corrosion resistance can be ensured by doing so. Even when the maximum amount of Si is contained, if the amount of Cu exceeds 1.0%, the corrosion resistance cannot be suppressed. Cu is an element which is more noble than pure aluminum in a solution containing Cl ions, and adjusts the relationship among Cu amount, Si amount, and Mg amount as described above, and has an average crystal grain size of 10 μm or less. By controlling to the subgrain structure, it is possible to make the potential nobler than pure aluminum, and further to prevent the formation of local batteries inside the material and improve the corrosion resistance in a solution containing Cl ions.

  Mn, Cr, and Zr effectively act to obtain a subgrain structure with an average crystal grain size of 10 μm or less in the alloy matrix. Mn, Cr, and Zr play the role of precipitating fine compounds of Al-Mn- (Si), Al-Cr, and Al-Zr in the matrix to form and maintain sub-crystal grains. The effect is improved by adding three elements in combination. Preferred contents are in the ranges of Mn: 0.15 to 0.43%, Cr: 0.05 to 0.23%, Zr: 0.05 to 0.24%, and all of Mn, Cr and Zr If the content is less than the lower limit, the effect of forming and maintaining sub-crystal grains is not sufficient, resulting in a coarse recrystallized structure, and if the content of at least one of Mn, Cr and Zr exceeds the upper limit, a huge intermetallic compound Is formed, reducing toughness and ductility. More preferable content ranges are Mn: 0.17 to 0.43%, Cr: 0.07 to 0.23%, Zr: 0.10 to 0.24%, and further preferable component ranges are Mn: 0.20. -0.40%, Cr: 0.10-0.20%, Zr: 0.12-0.22%.

  In the aluminum alloy extruded material of the present invention, it is important that the thickness center portion of the cross section of the extruded material has an average crystal grain size of 10 μm or less and the ratio of the subcrystal grain structure to the cross section is 70% or more. A sub-grain structure with an average grain size of 10 μm or less contributes to strength improvement and suppresses a decrease in corrosion resistance. When the strength of the entire material is considered by setting the ratio of the subcrystalline grain structure to the cross section to 70% or more, the strength reduction due to the recrystallized structure formed in the surface layer portion of the extruded material is not a problem and is sufficient. High strength can be maintained. In addition, the corrosion resistance of the recrystallized structure formed in the surface layer part of the extruded material may be reduced and intergranular corrosion may occur. .

  In order to obtain the above subgrain structure, prior to hot extrusion, the aluminum alloy ingot is homogenized at a low temperature of 400 to 480 ° C., and a heat reduction of 30% or more at a temperature of 480 to 550 ° C. It is desirable to perform interextrusion. When the homogenization temperature is lower than 400 ° C., decomposition of crystallized substances of Mn, Cr, and Zr that promote the formation of subgrain structure becomes insufficient. As a result, dispersion as a fine compound in the matrix is also insufficient, and sufficient subgrain structure formation is not achieved. If the homogenization temperature exceeds 480 ° C., it becomes difficult to form a stable subgrain structure during hot extrusion, and if the extrusion temperature is less than 480 ° C., the amount of processing strain introduced is high. A recrystallized layer is formed on the surface layer during solution treatment or heating before forging, and it may be impossible to ensure a subcrystal ratio of 70% or more. Further, depending on the area reduction rate, hot extrusion itself may be impossible. When the extrusion temperature exceeds 550 ° C., it is difficult to form and maintain the subcrystalline structure in the surface layer, and it becomes difficult to ensure the ratio of the subcrystalline structure in the cross section to 70% or more. Moreover, since the eutectic alloy having a melting point lower than that of the original Al—Mg—Si alloy is produced by containing the additive elements in a composite manner, there is a concern about the induction of cracks due to melting of the eutectic alloy. . By this extrusion process, a subcrystalline structure having a higher degree of focusing than that obtained by hot forging the ingot is obtained, and as a result, high strength and high toughness can be achieved. If the area reduction ratio of the hot extrusion is less than 30%, the degree of focusing of the sub-crystal grains becomes low, and it is difficult to obtain the sub-grain structure depending on the conditions. The extruded shape may be either a solid material or a hollow material, and the above-described texture property can be obtained even if extruded into any shape.

  Even when hot forging is performed after hot extrusion, the above subgrain structure is obtained after forging, and high strength and high toughness can be achieved. In this case, it is desirable that the hot forging temperature is in a temperature range of 480 to 550 ° C. When the temperature is lower than 480 ° C., plastic strain is easily introduced during forging. As a result, the sub-crystal grain area ratio in the cross-sectional structure after solution treatment is less than 70%, and the crystal grain size of the sub-crystal grains is 10 μm. It is feared that When the temperature exceeds 550 ° C., considering the heat generated during hot working, there is a concern about the induction of cracking due to melting of the eutectic alloy produced by the additive element.

  In the present invention, after hot extrusion or hot forging, solution treatment is performed at 510 to 570 ° C., and aging treatment is performed at 150 to 200 ° C., whereby predetermined strength and toughness can be obtained. By these treatments, the alloy elements contributing to the strength are sufficiently infused, and the infused alloy elements are finely precipitated in the matrix to increase the strength and toughness. When the solution treatment temperature is less than 510 ° C., the infiltration is insufficient and sufficient strength cannot be obtained. When the solution treatment temperature exceeds 570 ° C., not only the sub-crystal grain area ratio in the cross-sectional structure after solution treatment is less than 70%, but also there is a concern about induction of cracking due to melting of the eutectic alloy formed by the additive element. The When the aging treatment temperature is lower than 150 ° C., precipitation is insufficient and sufficient strength cannot be obtained. On the other hand, when the aging temperature is higher than 200 ° C., the precipitate becomes coarse, and as a result, sufficient strength cannot be obtained.

  Examples of the present invention will be described below in comparison with comparative examples to demonstrate the effects of the present invention. These examples show one embodiment of the present invention, and the present invention is not limited thereto.

Example 1
An aluminum alloy having the composition shown in Table 1 was melted and formed into a billet for extrusion having a diameter of 90 mm by a semi-continuous casting method. The obtained billet was homogenized at 450 ° C. and then hot extruded into a round bar having an extrusion temperature of 520 ° C. and a surface area reduction ratio of 95% and a diameter of 20 mm. Thereafter, solution treatment and aging treatment were performed under the conditions shown in Table 2.

Using the obtained material as a test material, the average crystal grain size at the thickness center and the ratio of sub-crystal grains in the cross section (sub-crystal grain area ratio) were investigated by the following methods. In addition, mechanical properties (tensile strength: σB, proof stress: σ0.2, elongation: δ) were measured, and toughness and corrosion resistance were further evaluated. The results are shown in Table 2.
Investigation of average crystal grain size: After electrolytic polishing of the cross section of the investigation, polarization micro observation was performed, and the average crystal grain size was calculated by image analysis.
Investigation of subcrystalline grain area ratio: After caustic etching of the investigation cross section, the subcrystalline grain area ratio was calculated by image analysis.
Measurement of mechanical properties: A JIS Z 2201 No. 4 test piece (similar shape according to Remark 2) was prepared and measured according to JIS Z 2241, and a proof stress of 400 MPa or more was regarded as acceptable.
Evaluation of toughness: After processing the test material into a JIS No. 3 impact test piece, a Charpy impact test was performed at room temperature, and a Charpy impact value of 25 J / cm ² or more was accepted.

Corrosion resistance evaluation: Based on the ISO / DIS11846B method, the following intergranular corrosion test was conducted, and the maximum corrosion depth of 50 μm or less was regarded as acceptable.
ISO / DIS11846 Method B
Pretreatment A. Cleaning solution (Nitric acid 50mL / L + hydrofluoric acid 5mL / L) Immerse for 1 minute at 95 ± 2 ℃. Water washing C.I. Immerse in nitric acid (room temperature) for 2 minutes. Water washing E. Drying test A. B. Test solution (NaCl 30g / L + hydrochloric acid 10mL / L) Continuous immersion for 24 hours at room temperature Amount of liquid Sample surface area x 5 mL / cm2 or more Post-treatment Flushing (running water)
B. Immersion in concentrated nitric acid for 30 seconds C.I. Flushing

  As seen in Table 2, the test materials 1 to 5 according to the present invention were excellent in mechanical properties, toughness (impact characteristics), and corrosion resistance, and all showed acceptable values.

Comparative Example 1
Alloy No. 1 in Table 1 A billet for extrusion of A was homogenized at 450 ° C. and then hot extruded into a round bar having an extrusion temperature of 520 ° C. (however, test material 8 is 560 ° C.) and a reduction in area of 95% and a diameter of 20 mm. The solution treatment and the aging treatment were performed under the conditions shown in FIG. Using the obtained material as a test material, the average crystal grain size at the center of thickness and the ratio of sub-crystal grains in the cross section (sub-crystal grain area ratio) were investigated in the same manner as in Example 1, and the mechanical properties and toughness were investigated. The corrosion resistance was evaluated. The results are shown in Table 3. In Table 3, those outside the conditions of the present invention are underlined.

  As shown in Table 3, the test material 6 has a low solution temperature, the test material 9 has a low aging temperature, and the test material 10 has a high aging temperature. Since the test material 7 has a high solution treatment temperature, the sub-crystal grain area ratio in the cross-sectional structure after the solution treatment is less than 70%, and the crystal grain size of the sub-crystal grains exceeds 10 μm. It failed in any of the mechanical properties, corrosion resistance, and toughness (Charpy impact property). Since the test material 8 had a high extrusion temperature, cracks occurred during extrusion, and the test material 8 could not be used for the test.

Comparative Example 2
Aluminum alloys having the compositions shown in Table 4 were melted and formed into a billet for extrusion having a diameter of 90 mm by a semi-continuous casting method. The obtained billet was homogenized at 450 ° C. and then hot extruded into a round bar having an extrusion temperature of 520 ° C. and a surface area reduction ratio of 95% and a diameter of 20 mm. Thereafter, solution treatment and aging treatment were performed under the conditions shown in Table 5. Using the obtained material as a test material, the average crystal grain size at the center of thickness and the ratio of sub-crystal grains in the cross section (sub-crystal grain area ratio) were investigated in the same manner as in Example 1, and the mechanical properties and toughness were investigated. The corrosion resistance was evaluated. The results are shown in Table 5. In Tables 4 and 5, those outside the conditions of the present invention are underlined.

  As shown in Table 5, since the test material 11 had a low amount of Si, the test material 13 had a low amount of Cu, and therefore all of the mechanical properties failed. Since the test material 12 had a low amount of excess Si relative to the Cu content, the test material 14 had a low Mg content and a high Cu content, so that both of them failed in corrosion resistance. Since the test material 15 has a low amount of Mn, Cr and Zr, the subcrystalline grain area ratio in the cross-sectional structure after solution treatment was less than 70%, and the crystal grain size of the subcrystalline grains exceeded 10 μm. It failed in any of properties, corrosion resistance, and toughness (Charpy impact property). Since the test material 16 had high amounts of Mn, Cr and Zr, the ductility was lowered and the Charpy impact property was rejected.

Example 2 and Comparative Example 3
The extrusion billet of alloy A in Table 1 was homogenized at 450 ° C. and then hot extruded into a round bar having an extrusion temperature of 520 ° C. and a surface area reduction ratio of 95% and a diameter of 20 mm. The obtained hot-extruded material was hot forged at temperatures of 520 ° C. and 450 ° C., both were solution treated at 535 ° C., and then aged at 180 ° C. Using the obtained material as a test material, the average crystal grain size at the center of thickness and the ratio of sub-crystal grains in the cross section (sub-crystal grain area ratio) were investigated in the same manner as in Example 1, and the mechanical properties and toughness were investigated. The corrosion resistance was evaluated. The results are shown in Table 6. In Table 6, those outside the conditions of the present invention are underlined.

  As shown in Table 6, the test material 17 according to the present invention was excellent in mechanical properties, toughness (impact characteristics), and corrosion resistance, and all showed acceptable values. On the other hand, since the test material 18 has a low forging temperature and plastic strain introduced at the time of forging, the subcrystalline grain area ratio in the cross-sectional structure after solution treatment is less than 70%, and the crystal grain size of the subcrystalline grains is small. As a result, it exceeded the mechanical properties, corrosion resistance, and toughness (Charpy impact property).

Claims (6)

Si: 0.7 to 1.4% (mass%, the same applies hereinafter), Mg: 0.55 to 0.95%, Cu: more than 0.43% and 1.0% or less, and Mn: 0 .15 to 0.43%, Cr: 0.05 to 0.23%, and Zr: 0.05 to 0.24%, and the balance is made of Al and impurities, and [ An aluminum alloy extruded material obtained by solution treatment and aging treatment of a hot extruded material of an aluminum alloy having a composition satisfying Si%] × 1.73− [Mg%]> [Cu%] × 1.03 , The thickness center part of the cross section of the extruded material has a subcrystalline structure having an average crystal grain size of 10 μm or less , the proportion of the subcrystalline structure in the cross section is 70% or more, and a proof stress of 400 MPa or more and 25 J Excellent corrosion resistance, characterized by having a Charpy impact value of at least / cm ² High strength, high toughness aluminum alloy extruded material. In the composition of the aluminum alloy, Mn is .17 to 0.43% Cr is from 0.07 to 0.23 percent, according to claim 1, wherein the Zr is characterized by a 0.10 to 0.24% High strength, high toughness aluminum alloy extruded material with excellent corrosion resistance. A method for producing an aluminum alloy extruded material according to claim 1 or 2, wherein the aluminum alloy having the composition according to claim 1 or 2 is hot-extruded and then subjected to a solution treatment at 510 to 570 ° C, 150 A method for producing a high-strength, high-toughness aluminum alloy extruded material excellent in corrosion resistance, characterized by aging treatment at ˜200 ° C. The method for producing a high-strength, high-toughness aluminum alloy extrudate excellent in corrosion resistance according to claim 3, wherein the hot extrusion is performed at a temperature of 480 to 550 ° C and an area reduction rate of 30% or more. An aluminum alloy forging material obtained by hot forging , solution treatment and aging treatment of the hot extruded material of the aluminum alloy having the composition according to claim 1 or 2, wherein the thickness center portion of the cross section of the forged material includes a mean grain size 10μm following sub grain structure, the ratio of nitrous grain structure occupying in the cross-section Ri der 70% or more and 400MPa or more strength and 25 J / cm ² or more Charpy impact value A high-strength, high-toughness aluminum alloy forging material with excellent corrosion resistance characterized by having . A method for producing the aluminum alloy forged material according to claim 5, wherein the hot extruded material of the aluminum alloy having the composition according to claim 1 or 2 is subjected to a solution treatment at 510 to 570 ° C after hot forging. A method for producing a high-strength, high-toughness aluminum alloy forging material excellent in corrosion resistance, characterized by aging treatment at 150 to 200 ° C.