JPH0239580B2 - CHOSOSEIALGOKIN - Google Patents

Description

[Detailed description of the invention]

This invention is based on Al having excellent superplastic properties.
It concerns alloys. In general, superplastic Al alloys are usually heated at temperatures of 400 to 600℃.
When subjected to high-temperature tensile deformation at a selected temperature within the range of
% or more, and this superplasticity
Al alloys have been used in construction materials panels and aircraft parts in recent years because, like plastic molding, for example, by blow molding plate materials using air pressure, complex-shaped or large-sized items can be integrally molded. It is used for manufacturing such as. At present, various component systems have been proposed and put into practical use as superplastic Al alloys, but none of them yet have satisfactory superplastic properties, and therefore, they cannot be used under harsh conditions. Has superior superplastic properties that can withstand processing
The development of Al alloys is strongly desired. This invention is based on superplastic
It provides an Al alloy that has superplastic properties significantly superior to Al alloys, and contains, in weight percent, Zn: 4 to 15%, Zr: 0.03 to 0.25%, and Sb: 0.01 to 1%. , and, if necessary, contains one or two of the following: Mg: 0.03 to 3.5%, Cu: 0.03 to 0.3%, and the remainder is Al and unavoidable impurities. It is something. Next, the reason why the composition of the Al alloy of the present invention is limited as described above will be explained. (a) Zn The Zn component has the effect of making crystal grains finer, making it easier to cause dynamic recrystallization during processing deformation, and making it easier for grain boundaries to move and slip at high temperatures. The superplastic properties are ensured by the content of 4%
If the content is less than 15%, the desired excellent superplastic properties cannot be secured, while if the content exceeds 15%, the rolling workability of the alloy tends to deteriorate. %. (b) Zr The Zr component is made by refining the casting structure and
During heat treatment or hot forming, they are finely dispersed from the supersaturated solid solution and precipitated in the form of relatively stable secondary phase particles, which not only have the effect of suppressing crystal grain recovery and recrystallization, but also have the effect of suppressing crystal grain recovery and recrystallization. It has the effect of suppressing the coarsening of recrystallized grains, thereby making it possible to obtain excellent superplastic properties, but if its content is less than 0.03%, the desired effect cannot be obtained. On the other hand, if the Zr content exceeds 0.25%, it will cause deterioration of superplastic properties when large ingots are manufactured by continuous casting, for example.
Because large intermetallic compounds tend to crystallize, which requires a special casting method and is impractical, the content was set at 0.03 to 0.25%. (c) Sb The Sb component has the effect of making the precipitation of Zr in the matrix more uniform and finer, thereby further improving the above-mentioned effects of Zr and ensuring extremely excellent superplastic properties. If the content is less than 0.01%, the desired effect cannot be obtained, while if the content exceeds 1%, an intermetallic compound: SbAl will be formed and the superplastic properties will deteriorate rapidly. Therefore, its content was set at 0.01 to 1%. (d) Mg The Mg component has finer grains,
In addition, it promotes the movement and sliding of grain boundaries to further improve superplastic properties, and also combines with Zn to impart precipitation hardenability to the alloy, so even better superplastic properties and strength are required. However, if the content is less than 0.03%, the desired improvement effect on superplastic properties will not be seen, while if the content exceeds 3.5%, rolling workability will deteriorate. Therefore, its content was set at 0.03 to 3.5%. (e) Cu The Cu component not only strengthens the base material by forming a solid solution therein, but also has the effect of shifting the optimum deformation temperature to a lower temperature side, and also improves corrosion resistance and stress corrosion cracking resistance when coexisting with Zr. Since it has the effect of improving these properties, it is included as necessary when these properties are required, but the content is
If the content is less than 0.03%, the desired effect cannot be obtained in the above action, while if the content exceeds 0.3%, the above action tends to deteriorate.
Its content was set at 0.03-0.3%. Note that the Al alloy of the present invention may contain one or more of Fe, Mn, Cr, Ti, and B as unavoidable impurities, and the content thereof is Fe: 0.5%. Below, Mn: 0.2% or less, Cr: 0.2% or less, Ti: 0.3% or less, and B:
If it is 0.1% or less, it will not have any adverse effect on superplastic properties. In addition, in the Al alloy of this invention, 400~
After homogenization at a temperature of 500°C for 1 to 48 hours, reduction rate within a temperature range of 250 to 530°C: hot rolling of 50% or more and processing rate of 40% or more The final thickness of the plate material is obtained by cold rolling at , but in this case, the above homogenization treatment is preferably performed at a gradual heating rate of 10 to 200°C/min to the treatment temperature. This is because the Zr precipitation becomes extremely fine and uniform, and as a result, excellent superplastic properties are ensured. Furthermore, when the Al alloy of the present invention is subjected to superplastic deformation processing, it recrystallizes during the process of heating to a predetermined deformation temperature and acquires superplastic properties. , there is no need to perform recrystallization heat treatment. Next, the superplastic alloy of the present invention will be specifically explained with reference to Examples. Example Al alloys 1 to 15 of the present invention and comparative Al alloys 1 to 4 having the compositions shown in Table 1 were prepared by a normal melting and casting method, and after being cast into an ingot, 10 The temperature is increased at a gradual temperature increase rate of °C/min,
Homogenization treatment was carried out under the condition of holding this temperature for 16 hours, and then the ingot was subjected to inter-rolling at a rolling start temperature of 460°C to form a hot-rolled plate with a thickness of 8 mm.

[Table] Subsequently, this hot-rolled sheet was cold-rolled under normal conditions to obtain a cold-rolled sheet with a final thickness of 1.6 mm. Next, the resulting Al alloys of the present invention 1~
15 and the cold rolled sheets of comparative Al alloys 1 to 4,
For the purpose of evaluating superplastic properties, deformation temperature: 530℃,
A high temperature tensile deformation test was conducted under the conditions of heating time to deformation temperature: 10 minutes, initial strain rate: 1.7×10 ^-3 /sec, and total elongation was measured. This measurement result is the first
Shown in the table. From the results shown in Table 1, the present invention Al alloy 1
Comparative Al alloys 1 to 15 all have excellent superplastic properties with a total elongation of 380% or more, whereas comparative Al alloys 1 and 1 have contents of Zn, Zr, and Sb that are each lower than the range of this invention. ~3, and comparative Al alloy 4, which has a higher Sb content,
All of them showed a total elongation of less than 270%, and it is clear that the desired superplastic properties cannot be secured. As mentioned above, the Al alloy of the present invention has extremely excellent superplastic properties and can sufficiently handle processing under severe conditions, thus significantly expanding its application field. It brings about industrially useful effects such as.

Claims (1)

[Claims] 1 Zn: 4 to 15%, Zr: 0.03 to 0.25%, Sb: 0.01 to 1%. Characteristic superplastic Al alloy. 2 Contains Zn: 4 to 15%, Zr: 0.03 to 0.25%, Sb: 0.01 to 1%, and further contains Mg: 0.03 to 3.5%, with the remainder consisting of Al and inevitable impurities (the above % by weight). 3 Contains Zn: 4 to 15%, Zr: 0.03 to 0.25%, Sb: 0.01 to 1%, and further contains Cu: 0.03 to 0.3%, with the remainder consisting of Al and inevitable impurities (the above % by weight). 4 Contains Zn: 4 to 15%, Zr: 0.03 to 0.25%, Sb: 0.01 to 1%, and further contains Mg: 0.03 to 3.5%, Cu: 0.03 to 0.3%, and the rest is Al. A superplastic Al alloy characterized by having a composition (the above weight %) consisting of unavoidable impurities.