JPH05179384A - High strength and high toughness aluminum alloy manufactured by spray deposition method - Google Patents

Abstract

PURPOSE:To provide an aluminum alloy manufactured by a spray deposition method, in which a 7000 series is used as a base and good in wear resistance, the coefficient of thermal expansion and mechanical strength (particularly, in tensile strength and toughness). CONSTITUTION:The objective aluminum alloy has a compsn. contg., by weight, 3 to 22% Si, 0.2 to 5% Cu, 1.2 to 6% Mg and 5 to 15% Zn and satisfying the conditions of 1.3<=Cu+Mg<=10% and 2.3<=Cu+Mg+Zn/5<=13, and the balance substantially Al with inevitable impurities. Moreover, prescribed amounts of at least one kind among Fe, Cr, Mn, Ni, Co, W, Mo, V, Ce and Y and at least one kind among Zr, B and/or Ti, Sb, Ca, K, Sr, Na and P may be incorporated therein.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high strength and high toughness aluminum alloy produced by a spray deposition method, and more particularly to a high strength and high toughness aluminum alloy having improved wear resistance and thermal expansion characteristics.

[0002]

2. Description of the Related Art Conventionally, aluminum alloys have been manufactured by casting, forging, powder metallurgy and the like. Of these, the casting method is a method of manufacturing an aluminum alloy member by injecting a molten aluminum alloy melted to a predetermined composition into a mold having a desired shape. In the forging method, an aluminum alloy member is manufactured by mechanically forging a cast aluminum alloy. In all of these methods, since the molten aluminum alloy is solidified in the mold, there is a problem that the solidification rate is slow and a fine crystal structure cannot be obtained. There is also the problem that it is difficult to improve.

The powder metallurgy method developed as a solution to the above problems of the casting method (forging method) sprays a molten aluminum alloy having a predetermined composition together with an inert gas from a nozzle to form fine particles. By forming a powder and hot working the powder into a predetermined shape, an aluminum alloy molded product is obtained. Since this powder metallurgy method can produce an aluminum alloy having a fine crystal structure, it is used to produce aluminum products having various compositions that cannot be produced by a casting method or a forging method.

However, in the powder metallurgy method, since the aluminum alloy powder is once formed, it is reheated and hot-worked to form the aluminum alloy member, so that the manufacturing cost is high. ..

Under these circumstances, it has been proposed to produce an aluminum alloy by the so-called spray deposition method.
In this spray deposition method, the atomized molten aluminum alloy is deposited in the form of fine particles, and the obtained deposit is hot-worked to obtain an aluminum alloy product. Such a spray deposition method is disclosed, for example, in JP-A-60-36631.
JP-A-2-258935, JP-A-3-2345 and the like.

Among them, the aluminum alloy called 7000 series is Si: 0.5 wt% or less, Fe:
0.5% by weight or less, Cu: 0.5 to 2% by weight, Mg: 2
~ 4 wt%, Zr: 8.5-15 wt%, Mn: 0.0
It has a composition of 5 to 1% by weight and Cr: 0.05 to 0.8% by weight, and is used as super super duralumin in various parts, but it has better wear resistance and heat resistance than Al-Si alloys. There is a problem that the expansion characteristics are inferior. Further, since it is a heat treatment type age-hardenable alloy, there is a problem that the strength decreases at a high temperature of 200 ° C. or higher. Therefore, the applicable range is limited.

Therefore, an object of the present invention is to provide an aluminum alloy produced by the spray deposition method based on the 7000 series, which has excellent mechanical strength (in particular, tensile strength and toughness at high temperature). That is.

[0008]

As a result of earnest research in view of the above object, the present inventor has found that by adding Si to an aluminum alloy containing Cu, Mg and Zn as essential components,
We have found a method by which eutectic Si and primary crystal Si crystallized in the structure can be dispersed, thereby improving wear resistance and thermal expansion characteristics, and Fe, Cr, Mn, Ni, Co,
At least one of W, Mo, V, Ce and Y, a combination of Zr and B and / or Ti, and further Sb and C
By adding at least one of a, K, Sr, Na and P in an appropriate combination, a finer crystal structure can be obtained, and as a result, good mechanical strength (tensile strength and impact resistance) is also exhibited. The present invention has been accomplished by discovering that it comes to be carried out.

That is, the high-strength and high-toughness aluminum alloy of the present invention is manufactured by the spray deposition method.
i: 3 to 22% by weight, Cu: 0.2 to 5% by weight, M
g: 1.2 to 6% by weight and Zn: 5 to 15% by weight, 1.3 ≦ Cu + Mg ≦ 10% by weight, and 2.3 ≦
It is characterized by satisfying the condition of Cu + Mg + Zn / 5 ≦ 13 wt%, and having a composition in which the balance substantially consists of Al and unavoidable impurities.

The high strength and high toughness aluminum alloy of the present invention further comprises Fe, Cr, Mn, Ni, Co, W, Mo,
At least one of V, Ce and Y: 0.5 to 13% by weight
May be included. The high strength and high toughness aluminum alloy of the present invention further comprises Zr: 0.1 to 2% by weight, and B and T.
At least one kind of i: 0.05 to 1% by weight may be contained in combination. The high strength and high toughness aluminum alloy of the present invention may further contain at least one of Sb, Ca, K, Sr, Na and P: 10 ppm or more.

[0011]

The present invention will be described in detail below. [1] Composition of aluminum alloy

(A) Si: 3 to 22% by weight Si is an element effective for improving the thermal expansion coefficient and mechanical strength, but if it is less than 3% by weight, these effects cannot be sufficiently exhibited. On the other hand, if the Si content exceeds 22% by weight, the elongation is reduced. The preferred Si content is 5
~ 12% by weight.

(B) Cu: 0.2 to 5 wt% Cu is an element having an action of improving tensile strength,
If it is less than 0.2% by weight, the effect cannot be sufficiently exhibited. On the other hand, when the Cu content exceeds 5% by weight,
Elongation and Charpy impact strength will decrease. The preferable Cu content is 0.5 to 3% by weight.

(C) Mg: 1.2 to 6% by weight Although Mg is an element having an action of improving tensile strength,
If it is less than 1.2% by weight, the effect cannot be sufficiently exhibited. On the other hand, when the content of Mg exceeds 6% by weight,
Elongation and Charpy impact strength decrease, and as a result, fracture toughness decreases. The preferable Mg content is 2 to 4% by weight.

(D) Zn: 5 to 15% by weight Zn has the function of increasing the solid solubility of the additive element and improving the mechanical strength when an aluminum alloy preform is formed by the spray deposition method. Is an element,
If it is less than 5% by weight, the effect cannot be sufficiently exhibited. On the other hand, if the Zn content exceeds 15% by weight, the elongation and the Charpy impact strength decrease, and as a result, the fracture toughness decreases. The preferable Zn content is 5.5 to 8.5% by weight.

(E) Cu + Mg: 1.3 to 10% by weight If Cu + Mg is less than 1.3% by weight, the effect of improving the tensile strength cannot be sufficiently exhibited. On the other hand, Cu + M
When g exceeds 10% by weight, elongation and Charpy impact strength decrease. The preferable Cu + Mg is 2.5 to 7% by weight.

(F) Cu + Mg + Zn / 5: 2.3-1
If 3% by weight of Cu + Mg + Zn / 5 is less than 2.3% by weight, the effect of improving the tensile strength cannot be sufficiently exerted. On the other hand, when Cu + Mg + Zn / 5 exceeds 13% by weight, elongation and Charpy impact strength decrease. Preferred Cu + M
g + Zn / 5 is 3.6 to 8.7% by weight.

(G) Heat resistance improving element: 0.5 to 13% by weight In the aluminum alloy of the present invention, as a heat resistance improving element,
It contains at least one of Fe, Cr, Mn, Ni, Co, W, Mo, V, Ce and Y. These elements have the effect of improving the mechanical strength at high temperatures (about 200 ° C. or higher), but if the amount is less than 0.5% by weight, the effect cannot be sufficiently exhibited. On the other hand, if it exceeds 13% by weight, segregation of intermetallic compounds having poor ductility will be caused. The preferable content of the heat resistance improving element is 2 to 7% by weight.

(H) Zr: 0.1 to 2% by weight Zr has a function as a grain refinement element,
If it is less than 1% by weight, the effect cannot be sufficiently exhibited. On the other hand, if it exceeds 2% by weight, the crystallized product becomes coarse. The preferable Zr content is 0.5 to 1.0% by weight.
Is.

(I) B and / or Ti: 0.05 to 1% by weight B and / or Ti also has an action as a grain refinement element, but if it is less than 0.05% by weight, its effect is sufficiently exerted. It cannot be exhibited and the Charpy impact strength cannot be improved. On the other hand, if it exceeds 1% by weight, the aluminum alloy becomes brittle and the Charpy impact strength also decreases. The preferable content of B and / or Ti is 0.1 to 0.4% by weight.

(J) Inoculation element: 10 ppm or more The aluminum alloy of the present invention further contains S as an inoculation element.
You may contain at least 1 sort (s) of b, Ca, K, Sr, Na, and P. These inoculum elements ensure the precipitation of fine spherical grains. This makes it possible to obtain high elongation and high toughness while maintaining mechanical strength such as tensile strength. Further, the inoculation element can prevent the crystal grains from coarsening during heat treatment or hot working. Such effects cannot be sufficiently obtained when the inoculum element content is less than 10 ppm. On the other hand, if it exceeds 2.0% by weight, segregation will be caused. Therefore, the preferable content of the inoculating element is 10 ppm to 2.0% by weight, more preferably 10 p.
pm-1% by weight, especially 10-40 ppm.

(K) Al and unavoidable impurities: balance The unavoidable impurities include S, C, Pb, and Be. The content of these unavoidable impurities needs to be 0.03% by weight or less for the purpose of preventing a decrease in mechanical strength of the aluminum alloy.

[2] Spray Deposition Method In the spray deposition method for producing the high-strength and high-toughness aluminum alloy of the present invention, a tundish for melting the aluminum alloy and an inert gas provided directly below the nozzle of the tundish are used. An apparatus having a jetting nozzle and a means for collecting and depositing aluminum alloy fine particles provided about 5 to 30 cm below the jetting nozzle is used. The inside of this device is placed in an inert gas atmosphere to prevent oxidation of the aluminum alloy.

In order to carry out the spray deposition method with such an apparatus, first, an aluminum alloy melted at 600 to 1000 ° C. in a tundish is discharged from a nozzle, and an inert gas is jetted at a high speed from a jet nozzle directly below. To do. Nitrogen gas, argon gas, helium gas or the like is used as the inert gas. The molten metal refined by this high-speed inert gas becomes aluminum alloy fine particles,
It is deposited on the collecting means below about 5 to 30 cm. The obtained aluminum alloy fine particles are usually about 0.5 to 150 μm.
Having a particle size of.

The deposited aluminum alloy fine particles are still 5
It is at a temperature of about 00 to 750 ° C. and is not completely solidified. Therefore, the aluminum alloy fine particles that are continuously deposited are fixed to form an aluminum alloy deposit. Within this deposit, the fine particles of aluminum alloy are usually 10 ° to 10 °.
Cool at a rate of ³ ° C / sec. As described above, since the spray deposition method has a higher cooling rate than the casting method, fine crystallized particles of Si and fine crystal grains can be obtained. On the other hand, even if the cooling rate is slower than that of powder metallurgy, not only does it have sufficient mechanical strength, but it also achieves grain refinement if it contains Zr, B and / or Ti, and an inoculation element. You can That is, it is possible to prevent the formation of acicular Fe-based precipitates and coarse particles of Si.

The aluminum alloy deposited body thus obtained is subjected to outer peripheral processing as required to obtain a preform having a predetermined shape. Then, hot working is applied to this preform. Examples of hot working include hot extrusion and swaging. In the case of hot extrusion, an aluminum alloy deposited body is removed by using an extruder having a die having a predetermined opening shape.
It is carried out by extruding at an extrusion ratio of 7 to 25 (expressed by an area ratio) at 0 to 500 ° C. In the case of upsetting, 50 to 80 at 400 to 500 ° C in the die.
The swaging ratio (expressed by the height ratio) is%.

The hot-worked aluminum alloy is usually subjected to heat treatment. The heat treatment includes T6 treatment and T7 treatment. T6 treatment is performed with aluminum alloy of 450 to 520.
Solution treatment at 1 to 50 ° C for 1 to 50 hours, then 90 to 150 ° C
Aging treatment for more than 24 hours. Also, T
The No. 7 treatment is the T6 treatment added with an aging treatment (5 to 20 hours) at 150 to 190 ° C.

The present invention will be described in more detail with reference to the following specific examples.

Examples 1 to 22 and Comparative Examples 1 to 5 Nitrogen gas (a liquidus line of each composition + temperature of 200 ° C.) of the composition shown in Table 1 was jetted from a nozzle having a diameter of 3.0 mm ( It was atomized at a gas pressure of 5 kg / cm ² ) to obtain an aluminum alloy powder having an average particle size of 40 μm, which was deposited on a collecting means at a spray distance of 150 mm. The aluminum alloy deposit thus obtained is subjected to outer peripheral processing to have a diameter of 80 mm and a length of 70 m.
A preform of m was obtained.

This preform was heated at 450 ° C. for 40 minutes and hot extruded at an extrusion ratio of 20. Next, as T6 treatment, solution treatment was performed at 470 ° C. for 1.5 hours, quenching by water administration, and aging treatment at 130 ° C. for 24 hours. Each of the heat-treated aluminum alloys was subjected to a wear resistance test, measurement of thermal expansion coefficient, a tensile test at room temperature and an impact test (Charpy test), and a tensile test at 200 ° C. The results are shown in Table 2.

Table 1 Chemical composition (wt%) Example No. Si Cu Mg Zn Fe Cr Ni Example 1 5 1.8 2.5 5.1 0.1 − − 2 12 1.8 2.5 5.1 0.1 − − 3 17 1.8 2.5 5.1 0.1 − − 4 22 1.8 2.5 5.1 0.1 − − Comparative example 1 0.2 1.8 2.5 5.1 0.1 − − 2 24 1.8 2.5 5.1 0.1 − − 35 5 <0.1 1.0 5.1 0.1 − − Example 5 5 0.2 1.2 5.1 0.1 − − 6 5 1.0 3.5 5.1 0.1 − − 7 5 2.0 4.0 5.1 0.1 − − 8 5 5.0 5.0 5.1 0.1 − − 9 5 2.0 3.5 9.2 0.1 − − 10 5 2.0 3.5 13.3 0.1 − − 11 5 2.0 3.5 14.7 0.1 − − Comparative Example 4 5 6.0 7.0 5.1 0.1 − − 55 2.0 3.5 17.2 0.1 − − Example 12 5 2.0 3.5 6.5 1.7 − − 13 5 2.0 3.5 6.5 1.2 1.8 − 14 5 2.0 3.5 6.5 1.1 1.2 0.8

Table 1 (continued) Chemical composition (% by weight) Example No. Si Cu Mg Zn Fe Cr Ni Example 15 5 2.0 3.5 6.5 1.0 1.1 − 16 5 2.0 3.5 6.5 0.7 1.0 − 17 5 2.0 3.5 6.5 1.1 1.2 0.8 18 5 2.0 3.5 6.5 1.1 1.2 0.8 19 1.2 2.0 3.5 6.5 1.1 1.2 0.8 20 1.2 2.0 3.5 6.5 1.1 1.2 0.8 21 1.2 2.0 3.5 6.5 1.1 1.2 0.8 22 1.2 2.0 3.5 6.5 1.1 1.2 0.8

[0033] Table 1 (Continued) Chemical composition (wt%) Example No. Zr Mn B Ti other embodiments 15 - 0.6 - - - 16 - - - - Y 0.05 17 0.8 - - - - 18 0.6 - - 0.08 - 19 0.5 − 0.005 0.06 − 20 0.6 − − 1.0 − 21 0.5 − 0.005 0.06 Sb 20ppm 22 0.5 − 0.005 0.06 P 10ppm + Ca 10ppm

Table 2 Examples of mechanical strength at room temperature No. σ _B ⁽¹⁾ σ _Y ⁽²⁾ Elongation ⁽³⁾ Charpy ⁽⁴⁾ K _IC ⁽⁵⁾ Example 1 59 57 9.4 6.1 21 2 61 57 8.7 3.2 17 3 62 58 5.1 1.9 14 4 63 58 3.1 1.0 13 Comparative Example 1 56 52 11.2 8.0 28 2 65 61 1.5 0.8 11 3 33.0 31.0 8.4 10.5 25 Example 5 48.1 46.5 7.8 8.1 23 6 53.1 48.7 7.1 5.7 20 7 60.0 58.0 6.0 4.5 18 8 63.1 59.2 4.8 2.1 15 9 54.1 48.2 6.8 5.1 19 10 55.3 48.3 6.9 5.4 17 11 55.7 49.1 7.4 5.4 18 Comparative Example 4 70.4 67.6 2.0 0.4 12 5 45.1 41.1 5.3 3.1 13 Example 12 56.9 52.1 7.2 5.7 19 13 13 63.7 55.3 7.9 5.8 19 14 64.1 56.7 8.1 5.9 20

Table 2 (continued) Example of mechanical strength at room temperature No. σ _B ⁽¹⁾ σ _Y ⁽²⁾ Elongation ⁽³⁾ Charpy ⁽⁴⁾ K _IC ⁽⁵⁾ Example 15 64.5 56.6 8.0 5.8 20 16 65.1 58.9 8.0 6.1 25 17 66.2 59.3 8.0 6.5 23 18 66.9 60.1 8.5 7.1 24 19 70.1 62.5 8.5 8.2 27 20 65.2 65.2 1.0 0.9 12 21 71.9 64.2 8.7 8.5 28 22 72.5 67.2 9.0 8.8 29

Table 2 (continued) Example of mechanical strength at 200 ° C. No. σ _B ⁽¹⁾ σ _Y ⁽²⁾ Elongation ⁽³⁾ Abrasion resistance ⁽⁶⁾ Thermal expansion coefficient ⁽⁷⁾ Example 1 24 22 16.1 ○ 20.1 2 26 22 12.5 ○ 18.2 3 27 23 9.5 ○ 18.1 4 32 27 7.4 ○ 16.3 Comparative Example 1 24 21 18.0 × 23.6 2 32 27 5.0 ○ 14.1 3 13.2 10.1 19.0 ○ 18.3 Example 5 18.2 14.2 14.2 ○ − 6 26.2 15.3 11.3 ○ -7 26.0 17.3 8.5 ○ -8 28.1 17.9 7.3 ○ -9 24.3 19.6 12.3 − -10 25.0 19.7 13.7 − -11 25.1 20.1 12.9 − − Comparative Example 4 24.0 20.5 6.2 ○ − 5 18.2 16.3 9.1 − − Example 12 29.5 25.1 10.1 − − 13 30.2 28.1 9.8 − − 14 33.7 28.9 11.4 − −

Table 2 (continued) Example of mechanical strength at 200 ° C. No. σ _B ⁽¹⁾ σ _Y ⁽²⁾ Elongation ⁽³⁾ Abrasion resistance ⁽⁶⁾ Thermal expansion coefficient ⁽⁷⁾ 15 32.5 27.7 11.5 − − 16 33.4 29.1 11.2 − − 17 35.0 30.0 11.9 − − 18 35.1 31.9 12.1 − − 19 37.4 30.3 11.9 − − 20 − − − − − 21 40.0 31.0 12.1 − − 22 41.2 31.5 13.5 − −

(Note): (1) Tensile strength (kgf / mm ² ). (2) Yield strength (kgf / mm ² ). (3) Growth (%). (4) Charpy impact value (kgfm / cm ² ). (5) Fracture toughness (MPa · m ⁻² ). (6) Abrasion resistance (using an Ogoshi dry abrasion tester, FC3
0 as mating material, friction speed of 1.99m / s, 600m
Was measured with a friction distance of 2.1 kg and a final load of 2.1 kg, and evaluated according to the following criteria. ) ○: 40 × 10 ^-7 mm ² / kg or less ×: 40 × 10 ^-7 mm ² / kg or more (7) Coefficient of thermal expansion (× 10 ^-6 ).

As is clear from Table 2, the aluminum alloy of the present invention has a large coefficient of thermal expansion, and has a comparative example in any of tensile strength, yield strength, elongation, impact strength, fracture toughness and wear resistance. It can be seen that it is better than the aluminum alloy of. Further, in the aluminum alloy of the present invention, it is found that the elongation and the impact strength are improved as the heat resistance improving element and the inoculating element are added.

Example 23 An aluminum alloy having the following composition was produced under the same conditions as in Example 1 except that the Si content (x) was changed. The wear amount of each aluminum alloy was measured, and the relationship between the Si content and wear resistance was determined. The results are shown in Table 3. Si: x wt% Cu: 1.8 wt% Mg: 2.5 wt% Zn: 5.1 wt% Fe: 0.1 wt%

[0041]

[0042]

As described above in detail, Zn is added to an aluminum alloy containing Si, Cu and Mg as essential components, and if necessary, heat resistance improving elements (Fe, Cr, Mn,
At least one of Ni, Co, W, Mo, V, Ce and Y
Seed), Zr and B and / or Ti, and inoculum (S
When at least one of b, Ca, K, Sr, Na and P) is added in combination, the wear resistance and the thermal expansion coefficient are increased and the heat resistance is imparted. Further, since the aluminum alloy of the present invention has a fine crystal structure, it exhibits excellent mechanical strength (not only tensile strength but also elongation and toughness). Such an aluminum alloy of the present invention can be used for various machine parts, building materials, structural materials and the like, including automobile parts such as connecting rods and valves, which are required to be lightweight and have high mechanical strength.

Front page continuation (72) Inventor Kenichiro Shiokawa 1-4-1 Chuo, Wako, Saitama Stock Company Honda R & D Co., Ltd.

Claims (4)

[Claims] 1. A high-strength and high-toughness aluminum alloy produced by the spray deposition method, wherein Si: 3 to 22% by weight.
And Cu: 0.2-5 wt%, Mg: 1.2-6 wt%
And Zn: 5 to 15 wt%, 1.3 ≦ Cu +
Mg ≦ 10 wt%, and 2.3 ≦ Cu + Mg + Zn / 5
An aluminum alloy which satisfies the condition of ≦ 13% by weight, and has a composition substantially consisting of Al and unavoidable impurities as the balance. 2. The high-strength and high-toughness aluminum alloy according to claim 1, further comprising Fe, Cr, Mn, Ni and C.
at least one of o, W, Mo, V, Ce and Y: 0.
An aluminum alloy containing 5 to 13% by weight. 3. The high-strength and high-toughness aluminum alloy according to claim 1 or 2, further containing Zr: 0.1 to 2% by weight, and at least one of B and Ti: 0.05 to 1% by weight. An aluminum alloy characterized by being. 4. The high-strength and high-toughness aluminum alloy according to claim 1, further comprising Sb and C.
at least one of a, K, Sr, Na and P: 10 pp
An aluminum alloy containing m or more.