JPH01259150A - Manufacture of high-strength al-cu-li-mg-zr superplastic sheet - Google Patents

Abstract

PURPOSE:To manufacture an Al alloy sheet reduced in anisotropy, having high strength, and capable of plastic deformation by subjecting an ingot of an Al alloy containing specific amounts of Li, Cu, Mg, Zr, and Ti to homogenizing treatment or further to solution heat treatment and then applying rolling to the above under specific conditions. CONSTITUTION:An ingot of an Al alloy having a composition containing, by weight, 1.7-2.3% Li, 1.8-3.0% Cu, 1.1-3.0% Mg, 0.05-0.20% Zr, and 0.01-0.10% Ti is subjected to single-stage or multistage homogenizing treatment at 450-540 deg.C for 1-50h. Subsequently, the above ingot is subjected to solution heat treatment at >=460 deg.C and then to heating at 300-450 deg.C for 1-50h to undergo precipitation treatment and successively rolled at the above temp. so as to be worked into a metal sheet. At this time, rolling is carried out while regulating the equivalent strain rate represented by equation I to <=10S<-1>. By this method, the high-strength superplastic Al alloy sheet reduced in anisotropy at high temp. in the range of strain rate where deformation rate is extremely high can be manufactured.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing an Al-Li alloy plate that is capable of superplastic deformation, and more specifically relates to a method for producing an Al-Li alloy plate that is capable of superplastic deformation, and more specifically, it relates to a method for producing an Al-Li alloy plate that is capable of superplastic deformation, and more specifically, it relates to a method for producing an Al-Li alloy plate that is capable of superplastic deformation, and more particularly, it relates to a method for producing an Al-Li alloy plate that is capable of superplastic deformation, and more specifically, it relates to a method for producing an Al-Li alloy plate that can undergo superplastic deformation, and more specifically, The present invention relates to a method of manufacturing an Al-Cu-Li-Mg-Zr based superplastic aluminum alloy plate with little anisotropy and capable of superplastic deformation by rolling.

[Prior Art] In order to reduce the weight of the aircraft, aluminum alloy plates for aircraft are made of AI-Cu-Mg-based 2024 alloy plates and A
There is a transition from I-Z n -M g-Cu based 7075 alloy plates to lower density Al-Li based alloy plates.

In addition, the forming technology has been changed from the conventional method of assembling and joining products that have been roll-formed or press-formed (sheet metal processing) to integrated processing or 11J-capable superplastic forming.

The superplastic molding method allows products with complex shapes to be molded in one go, so there are fewer joints between parts, which makes it lighter. It also reduces assembly man-hours, reducing manufacturing costs. .

For this reason, an Al-Li alloy material that is capable of superplastic deformation is required.

Conventionally, Al-Li-Cu-
Mg-Zr based 8090 alloy and Al-Cu-Li-Zr
The 2090 alloy is internationally registered. Among these, in order to obtain superplastic deformation of the Al-Li-Cu-Mg-Zr alloy, the homogenization treatment temperature, hot working temperature,
Methods have been proposed to regulate the intermediate annealing temperature and degree of cold working. (Japanese Patent Application Laid-Open No. 62-1704G2) However, there is no material that can achieve superplastic deformation in the strain rate range where the deformation rate of AI-Cu-Li-Mg-Zr alloys is extremely high, and the development of such a material is difficult. It was strongly requested.

1'6- [Problem to be solved by the invention] As mentioned above, in order to manufacture superplastic materials, various processing is performed, but if the working degree of cold rolling is high at this time, rolling The elongation differs depending on the direction, and when subjected to superplastic deformation processing, the elongation in the direction h perpendicular to the rolling direction is low.

In addition, if it is necessary to increase the degree of cold working, 1.5 mm
It has not been possible to produce superplastic material of thicker plates than this. The present invention provides superplastic deformation in an extremely high deformation rate range,
Moreover, there is little anisotropy in the rolling direction depending on the rolling direction, and 1.
A plate with a thickness of 5 mm or more is A I-Cu-L i -Mg
-Z Provides a method for manufacturing by controlled rolling of r-based alloy material.

[Means for Solving the Problems] In order to achieve the above object, the method for manufacturing a superplastic aluminum alloy plate with low anisotropy according to the present invention is configured as follows.

(1) Li 1.7-2.3%, Cu 1.8-3
．． 0%, Mg 1.1-3.0%, Zr 0.0
5-0.20%, T10, old-0. After melting and casting an aluminum alloy containing 10% and the remainder Al and unavoidable impurities by a normal casting method, a single or multi-stage homogenization treatment is performed at a temperature of 450 to 540°C for 1 to 50 hours, and then 300 High-strength Al- is rolled at a temperature of ~450°C, and adjusted so that the equivalent strain rate expressed by the following formula is 10 s-1 or less during the rolling.
A method for producing a Cu-Li-Mg-Zr superplastic plate.

However, Vll = roll circumferential speed (m/5) R- = roll radius after flattening (m) ho = plate thickness before rolling (m) r = rolling reduction ratio (2) Li 1.7 to 2. 3%, Cu 1.8-3
．． 0%, Mg1.1-3.0%, Z r O, 05-0
．． 20%, Ti0101~0.10%, balance A
An aluminum alloy consisting of l and unavoidable impurities is usually melted by a casting method of = 8-, and after casting, it is subjected to a single or multi-stage homogenization treatment for 1 to 50 hours at a temperature of 450 to 540 °C and 30 to 30 hours of homogenization.
Precipitation treatment is performed at 0 to 450°C for 1 to 50 hours, and then rolled at a humidity of 300 to 450°C, and during rolling, the equivalent strain rate shown in the above formula is adjusted to be 105-' or less, and rolled. High strength Al-Cu-Li characterized by
- A method for producing a Mg-Zr superplastic plate.

(3) Li 1.7-2.3%, Cu 1. ．． 8～
3.0%, MgL, 1-3.0%, ZrO,
An aluminum alloy containing 0.05-0.20%, Ti0101-0.10%, and the balance consisting of Al and unavoidable impurities is melted by a normal casting method, and after casting, it has a melting point of 450-540%.
After holding for 1-50 hours at a temperature of 300-450 °C
℃, held for 1 to 50 hours, rolled in the temperature range, and adjusted so that the equivalent strain rate expressed by the above formula is equal to or lower than LOs' during the rolling. High strength A I-Cu-L i-Mg-Z
A method for producing an r-based superplastic plate.

(4) Li 1.7-2.3%, C
u1. ．． 8-3.0%, Mg1. l −
3.0%, ZrO,, 05~0.20%, T
An aluminum alloy containing 10.01% to 0.10% and the remainder consisting of Al and unavoidable impurities is melted by a normal casting method, and after casting, it is subjected to single or multistage homogenization treatment at 450 to 540°C for 1 to 50 hours. After that, the material is heated to 460°C or higher again, subjected to solution treatment, and then rolled at a temperature of 300 to 450°C, and during the rolling, the equivalent strain rate shown by the above formula is adjusted to be 10 s-l or less. Rolling, precipitation treatment at 300 to 450°C for 1 to 50 hours during the rolling, and then further adjusting at 300 to 450°C so that the equivalent strain rate shown in the above formula is tos-' or less, High strength AI-Cu-L i-M characterized by rolling
Method for manufacturing g-Z r-based superplastic plate.

[Function] The Al-Li based superplastic abrasive material is similar to the conventional 7475 alloy based superplastic abrasive material, and has the property of forming fine recrystallized grains through dynamic recrystallization and superplastic deformation. This makes it possible to obtain feed that has a substructure that is stable up to high temperatures.

The present invention relates to a manufacturing method for improving the hot workability of A1-Cu-Li-Mg-Zr system and rolling it to obtain a superplastic material, and the reason for limiting the following components: Let's talk about.

Ll, it is effective in improving the strength and reducing the weight of the alloy after superplastic forming. If this effect is less than 1.7%, the strength will be insufficient and the weight reduction effect of adding Li will also be reduced. If it exceeds 2.7%, it is not preferable because it imposes restrictions during casting.

Cu, strength improvement of alloy mill after superplastic forming e.g. 45kg
It is effective for obtaining a tensile strength of /mm' or more. This effect cannot be obtained if it is less than 1.8%, and if it is more than 3.0%, the density of the effect of Cu is high and it cannot contribute to weight reduction of aircraft etc.

Mg; To obtain a tensile strength of 45 kg/mm2 or more, 1.1% or more is required, and if it exceeds 3.0%, A
It becomes easy to form lCuMg-based crystallized substances, and it is difficult to form a solid solution again.

Zr: has the effect of suppressing recrystallization of alloy slag.

If it is less than 0.05%, it will be easy to recrystallize in the final annealing, making it difficult to stabilize the dot structure. For this reason, it is difficult to obtain superplastic molding. Moreover, if it exceeds 0.20%, giant compounds tend to crystallize in normal casting methods, which causes rolling defects in the material.

Tl: Has the effect of making the casting structure finer in the Sori alloy. This effect is 0. You cannot get it if it is less than the old %, 010%
When the amount is higher, giant compounds tend to crystallize.

Next, the manufacturing conditions will be described.

Homogenization process.

The homogenization treatment has the effect of reducing grain boundary segregation of solute atoms such as CuXLi and Mg and making the components uniform. 450℃
Not yet 11. At lv4, the effect is small, and when the temperature exceeds 540°C, recrystallization inhibiting elements such as Zr or precipitates as a stable phase.
The effects of those elements will be reduced. Furthermore, if the time is less than 1 hour, the effect of homogenizing the components will be small, and if it exceeds 50 hours, the effect will be saturated, so it is economically meaningless. 4
It is best to perform step heating once at about 20°C.

Rolling temperature: The reason why the rolling temperature is 300 to 450℃ is because this temperature range is δ
, T phase (AlLiMg) and other stable phases are precipitated, and when rolled in this temperature range, a stable substructure is formed.

Precipitation treatment.

300~450℃ precipitation treatment for 1~50 hours
If rolling is carried out before or during rolling at a temperature of 450°C, the δ phase and T phase will precipitate uniformly, and multiple slips will occur near this second phase, resulting in the formation of a stable substructure. . In addition, because it precipitates uniformly within the grains, deformation within the grains becomes easy and hot rolling cracks are less likely to occur.

If the precipitation treatment time is shorter than 1 hour, hot rolling cracks may occur depending on the state of precipitation before rolling. In addition, the effect does not change if it is for 50 hours or more.

Rolling strain rate.

In order to form a stable substructure during the above rolling,
The strain rate during warm working is important; the faster the rolling speed, the higher the strain rate, which makes it easier for dislocations to accumulate and cause rolling cracks. Furthermore, if the strain rate is slow, precipitates will aggregate too much, dislocations will recover quickly, and a stable substructure will be difficult to form. There is also the problem of poor productivity. The appropriate rolling speed is converted to the equivalent strain rate,
It may be less than or equal tos-'. Note that the lower limit is approximately O,ls''.

[Example] Al-2,2%Li-2,4%Cu-1,6%Mg-
A 0.11% Zr-11.05% Ti alloy was melted and cast in an argon gas atmosphere. After the homogenization heat treatment of the ingot, controlled rolling was performed by changing the rolling temperature, rolling speed, and reduction amount. The precipitation treatment was performed before or during rolling. Table 1 shows the relationship between the manufacturing conditions and superplastic elongation of the manufactured plates. The superplastic elongation was measured in the rolling direction and the direction perpendicular to the rolling direction in order to measure the anisotropy by 91J. The rolling was carried out by heating to the rolling start temperature 14) every 1 to 3 passes.

The evaluation in the table is 1 at 500°C for the high temperature tensile test, [i
x 1O-3s-', the elongation was 3
00% or more was rated as ○, and anisotropy was rated as ○ if the ratio of the elongation in the rolling direction to the elongation in the direction perpendicular to the rolling was within 2.

Example 2 A I-L i-Cu-Mg-Zr alloy was melted and cast in an argon gas atmosphere. After homogenization heat treatment at 500° C. for 24 hours, surface side treatment is performed to remove surface segregation layers, oxides, pores, and shrinkage pores. Castings with a large amount of surface cutting were considered to have poor castability, and their castability was evaluated. Also, 400
After precipitation treatment for ℃XIO hours, rolling was started at 400℃ and 3
Reheat at 00℃ and reduce the equivalent strain rate of rolling to 2.2s-
Control rolling was performed as Step 1 to obtain a final plate with a thickness of 2+ nm.

In order to investigate the room temperature strength characteristics of this feed, 520℃ x 1
After solution treatment in a salt bath and water cooling, 1 day later, 190
It was tempered at ℃ for 16 hours. Al-Li-Cu-Mg-Zr
Table 2 shows the composition, castability, strength, high-temperature elongation, and overall evaluation of the alloys. Even with alloy No. 2.3.4, which falls outside the range of alloy components targeted by the present invention, the method of the present invention is not without its effect on high-temperature elongation.

Table 2' 45kg/mm or more is preferable***
A tensile test was conducted at 500° C. and a strain rate of t, ex IQ-1s-' in parallel to the rolling force direction.

[Effects of the Invention] According to the manufacturing method of the present invention, the following effects can be obtained.

(1) Al-C produced by the method of the present invention.

-Ll-Zr alloy plate has a non-recrystallized structure, so the deformation rate is made one order of magnitude higher than that of conventional superplastic aluminum alloy plate (for example, 7475 alloy) due to this structure. It can be transformed.

(2) According to the present invention, by performing controlled rolling or further final annealing by rapid heating, the structure at the time of casting can be destroyed and grain boundary impurities at the time of casting can be removed from the grain boundaries. As a result, the superplastic properties of the alloy can be improved, and parts with complex shapes for aircraft, vehicles, automobiles, etc. can be easily manufactured.

Patent Applicant: Sumitomo Light Metal Co., Ltd. Agent: Hide Komatsu, Attorney: Hiroshi Asahi, Attorney: Hiroshi Asahi

Claims (4)

[Claims] (1) Li1.7-2.3%, Cu1.8-3.0%,
Mg1.1-3.0%, Zr0.05-0.20%, T
An aluminum alloy containing 0.01 to 0.10% i and the balance consisting of Al and unavoidable impurities is melted and cast by a normal casting method, and then cast at a temperature of 450 to 540 °C to 1 to 5
Single or multi-stage homogenization for 0 hours, then 30 hours
High-strength Al-Cu-Li-, which is characterized by rolling at a temperature of 0 to 450°C, and adjusting the equivalent strain rate shown by the following formula to be 10 s^-^1 or less at the time of rolling.
A method for producing a Mg-Zr superplastic plate. Formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ However, V_R = Roll circumferential speed (m/s) R' = Roll radius after flattening (m) h_0 = Plate thickness before rolling (m) r = Reduction rate (2) Li1.7-2.3%, Cu1.8-3.0%,
Mg1.1-3.0%, Zr0.05-0.20%, T
An aluminum alloy containing 0.01 to 0.10% of i and the balance consisting of Al and unavoidable impurities is melted by a normal casting method, and after casting, it is heated to 1 to 0.1% at a temperature of 450 to 540°C.
Single or multi-stage homogenization treatment for 50 hours and 300-450
℃ for 1 to 50 hours, then 300 to 4
High strength Al-Cu-Li-Mg-, characterized by rolling at a temperature of 50°C and adjusting the equivalent strain rate shown in the following formula to be 10s^-^1 or less during the rolling.
A method for manufacturing a Zr-based superplastic plate. Formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ However, V_R = Roll circumferential speed (m/s) R' = Roll radius after flattening (m) h_0 = Plate thickness before rolling (m) r = Reduction rate (3) Li1.7-2.3%, Cu1.8-1.7%,
Mg1.1-30%, Zr0.05-0.20%, Ti
An aluminum alloy containing 0.01 to 0.10% and the balance consisting of Al and unavoidable impurities is melted by a normal casting method, and after casting, it is heated to 1 to 5% at a temperature of 450 to 540°C.
After holding for 0 hours, cool to a temperature of 300 to 450°C, and
After holding for ~50 hours, the high strength Al- A method for producing a Cu-Li-Mg-Zr superplastic plate. Formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ However, V_R = Roll circumferential speed (m/s) R' = Roll radius after flattening (m) h_0 = Plate thickness before rolling (m) r = Reduction rate (4) Li1.7-2.3%, Cu1.8-3.0%,
Mg1.1-3.0%, Zr0.05-0.20%, T
An aluminum alloy containing 0.01 to 0.10% i with the balance consisting of Al and unavoidable impurities is melted by a normal casting method, and after casting, it is subjected to single or multi-stage homogenization treatment at 450 to 540°C for 1 to 50 hours. After that, it is heated again to 460°C or higher, subjected to solution treatment, and then rolled at a temperature of 300 to 450°C, and in the middle of the rolling, it is heated at 300 to 450°C.
~50 hours of precipitation treatment, then an additional 300~450 hours
High strength A characterized by adjusting and rolling so that the equivalent strain rate shown by the following formula at °C is 10 s^-^1 or less
A method for manufacturing a l-Cu-Li-Mg-Zr based superplastic plate. Formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ However, V_R = Roll circumferential speed (m/s) R' = Roll radius after flattening (m) h_0 = Plate thickness before rolling (m) r = Reduction rate