JP6784962B2 - Aluminum-based alloy - Google Patents

Description

The present invention relates to an aluminum-based alloy having a high Young's modulus by dissolving a special additive element in an aluminum matrix.

The application of aluminum alloys has expanded as the demand for weight reduction of vehicles and aircraft has increased, but when replacing conventional iron-based materials with aluminum materials, the reduction in rigidity due to the decrease in Young's modulus is a major issue. It has become. In order to deal with such a problem, the rigidity has been improved by the combined effect of aluminum and ceramics (for example, Patent Documents 1 to 4).

Patent No. 4825776 Patent No. 4119357 Patent No. 4119348 Patent No. 3391636

However, a composite material containing a reinforcing material for ceramics has a problem that the manufacturing cost is high because the manufacturing process is complicated. In addition, since it contains hard particles, there is a problem that machining becomes difficult. Therefore, an object of the present invention is to provide an aluminum-based alloy that can be made highly rigid without containing hard particles such as ceramics, has a simple manufacturing process, and is easy to machine.

In order to increase the Young's modulus of the aluminum-based alloy, the present inventors have conducted intensive studies on solid solution and strengthening by aging. As a result, it was found that high rigidity can be achieved by substituting Al with an element having an atomic radius smaller than that of Al (according to the calculation result). That is, the electron density is improved by the added element and the interatomic distance (interstitial distance) is shortened, so that the binding energy can be increased and the rigidity can be increased. As a result of investigating the atomic radii of the elements from the first period to the fifth period of the periodic table, the atomic radii of Cu, Zn, Ag, and Li are -10.5, respectively, of the atomic radii of Al. %, -6.99%, + 1.05%, and + 5.70%.

In addition, the present inventors calculated the Young's modulus of the aluminum-based alloy when Al contained an additive element of 25 at% for the elements from the first cycle to the fifth cycle of the periodic table. The theoretical formula used for the calculation is the following equation 1, in which E is Young's modulus, r is the interatomic distance in the crystal lattice (face-centered cubic lattice), and A, n, and m are element-dependent constants. Then, Young's modulus was calculated by analysis software (CASTEP, supercell model) using the following mathematical formula. The analysis software was set to generalize density gradient approximation, energy cutoff to 350 eV, and K point set to 6 × 6 × 6.

Comparing the calculated Young's modulus of each aluminum-based alloy with the Young's modulus of pure aluminum, the amount of additive elements added to each aluminum-based alloy was converted to 1 wt% to obtain the Young's modulus increase rate. The rates of increase in Young's modulus of Ag and Li were 0.65%, 0.04%, 0.24%, and 0.95%, respectively.

Furthermore, the present inventors, if a large amount of additive elements can be supersaturated in solid solution in Al, an intermediate layer (intermetallic compound between Al and additive elements, intermetallic compound between additive elements, etc.) due to the difference from the solid solution limit at the aging temperature. ), We realized that further high rigidity could be achieved, and investigated the elements from the first cycle to the fifth cycle of the periodic table. As a result, the maximum solid solution amounts of Cu, Zn, Ag and Li in Al were 2.48 wt%, 49.1 wt%, 23.9 wt% and 13.9 wt%, respectively.

Since increasing the rigidity of the aluminum-based alloy is considered to be a synergistic effect of the above-mentioned increase rate of Young's modulus and the maximum solid solution amount, the product of the two is calculated as Cu: 1.612, Zn: 1.964, Ag. : 5.736 and Li: 13.205, and all other elements were less than 1.

The present invention has been made based on the above findings, and is composed of two or more types of Cu, Zn, Ag and Li, and the balance is unavoidable impurities and Al. In mass%, Cu is more than 0% and more than 4%. Zn is 10% or more and 20% or less, Ag is more than 0% and 10% or less, Li is 0.05% or more and 0.5% or less, and the total amount of Cu, Zn, Ag and Li is Is an aluminum-based alloy that is 14% or more and 30% or less .

The method for producing an aluminum-based alloy of the present invention is characterized in that the above-mentioned aluminum-based alloy is subjected to solution heat treatment and quenching, followed by aging treatment at 90 to 170 ° C. for 120 to 240 hours.

According to the present invention, it is possible to provide an aluminum-based alloy in which Young's modulus is dramatically improved and rigidity is remarkably increased due to the effect of forming a solid solution of an additive element and an intermediate phase on an aluminum matrix. Therefore, according to the present invention, it is possible to reduce the weight by increasing the wall thickness of parts such as brake calipers, which are dominated by rigidity, and to design a compact shape by reducing the wall thickness. Is possible.

It is a perspective view which shows the Young's modulus measuring apparatus. It is a graph which shows the relationship between the aging time and Young's modulus of the aluminum-based alloy in the Example of this invention.

1. 1. First Example Next, the present invention will be described in detail with reference to specific examples.
A rectangular sample having a width of 10 mm, a length of 60 mm, and a thickness of 1.5 mm was prepared from an aluminum-based alloy having the composition shown in Table 1, and a solution treatment was performed in which the sample was held at 520 ° C. for 4 hours and put into water. After that, an aging treatment was performed in which the mixture was held at 110 ° C. for 24 hours. Next, the Young's modulus of the sample is measured a plurality of times, and the maximum value thereof is also shown in Table 1.

FIG. 1 shows a Young's modulus measuring device (JE-RT manufactured by Nippon Techno Plus). In this measuring device, the sample TP is held by two suspension wires 1, and a capacitor is formed in the space between the drive pole 2 and the sample TP to generate natural vibration, which is a non-contact vibration sensor 3. Detect with and measure Young's modulus. This measuring method complies with JIS Z 2280.

As shown in Table 1, in Examples 1 to 5, Young's modulus is higher than that of the reference material made of pure aluminum. In particular, in Example 5 containing Cu, Zn, Ag, and Li, an extremely high Young's modulus could be obtained.

2. Second Example A sample was prepared under the same conditions as in the first example except that the aging treatment was carried out at 90 ° C. for 10 days, and the Young's modulus was measured. The results are shown in Table 2. In addition, the Young's modulus calculated using the above-mentioned equation 1 is also shown in Table 2.

As shown in Table 2, the Young's modulus calculated using Equation 1 is very close to the measured value, confirming the validity of selecting Cu, Zn, Ag, and Li.

3. 3. Third Example A sample of an aluminum-based alloy was prepared under the same conditions as in the first example except that the components and aging treatment conditions were as shown in FIG. As shown in FIG. 2, it was confirmed that when the aging temperature was 170 ° C., a Young's modulus of 77 GPa or more was obtained by aging for 240 hours. It was also confirmed that when the aging temperature was 110 ° C., a Young's modulus of 78 GPa or more was obtained by aging for 1500 hours.

The present invention can be used for automobile parts and the like where rigidity is required due to high rigidity.

Claims (2)

Two or more kinds of Cu, Zn, Ag and Li, and the balance is composed of unavoidable impurities and Al, and in mass%, Cu is more than 0% and 4% or less, Zn is 10% or more and 20% or less. Ag is more than 0% and 10% or less, Li is 0.05% or more and 0.5% or less, and the total amount of Cu, Zn, Ag and Li is 14% or more and 30% or less. .. A method for producing an aluminum-based alloy, which comprises subjecting the aluminum-based alloy according to claim 1 to solution heat treatment and quenching, and then performing an aging treatment at 90 to 170 ° C. for 120 to 240 hours.

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