CN109022964B - 7000 series as-cast aluminum alloy with high hardness of 89-104mm and hardenability - Google Patents

Abstract

A high-hardness 89-104mm hardenability 7000 series cast aluminum alloy and a preparation method, characterized in that the aluminum alloy is mainly composed of aluminum (Al), zinc (Zn), magnesium (Mg), copper ( Cu) and zirconium (Zr), wherein the mass percentage of zinc (Zn) is 9.47-11.99%, the mass percentage of magnesium (Mg) is 2.93-3.05%, and the mass percentage of copper (Cu) is 1.27-2.34%, The mass percentage of zirconium (Zr) is 0.175-0.193%, and the balance is aluminum and a small amount of impurity elements. The preparation of the alloy sequentially includes: (1) melting and casting; (2) homogenization treatment; (3) solution treatment and (4) aging treatment. The actual measured hardness of the invention can reach up to 223.75HV, the maximum as-cast end quenching and hardening depth can reach 104mm, the elongation rate is 7.6%, and the electrical conductivity is 30.275% IACS.

Description

A high hardness 89-104mm hardenability 7000 series as-cast aluminum alloy

technical field

The invention belongs to the field of metal alloys, in particular to a high-hardness and high-hardenability 7000 series as-cast aluminum alloy, in particular to a high-hardness 89-104 mm hardenability 7000-series as-cast aluminum alloy.

Background technique

7000 series aluminum alloy is an indispensable key pillar material in the development of modern aerospace and weapons and equipment. Its development level not only reflects a country's comprehensive scientific and technological strength, but also is an important guarantee for a country's national defense security. For a long time, the development of aluminum alloys with more balanced and optimized comprehensive properties has been a high-tech field prioritized by countries all over the world.

In the aerospace industry, in order to achieve the goals of weight reduction, high reliability and long life, the main load-bearing components often use thick plates, extra-thick plates, large forgings and large profiles, which not only requires the strength (hardness) of 7000 series aluminum alloys In addition, higher requirements are placed on its properties such as hardenability (quenching sensitivity), so as to ensure the core performance of large load-bearing members.

So far, there is no aluminum alloy with independent intellectual property rights of as-cast end quenching and hardening depth of 100mm and hardness of more than 210HV available for use, which restricts the development of my country's aerospace, weaponry and other industries to a certain extent.

SUMMARY OF THE INVENTION

The purpose of the present invention is to invent a high-hardness 89-104mm hardenability as-cast 7000 series aluminum alloy and a preparation method thereof through component design and preparation technology design.

One of the technical solutions of the present invention is:

A high-hardness 89-104mm hardenable as-cast aluminum alloy is characterized in that: it is mainly composed of aluminum (Al), zinc (Zn), magnesium (Mg), copper (Cu) and zirconium (Zr), wherein, The mass percentage of zinc (Zn) is 9.47-11.99%, the mass percentage of magnesium (Mg) is 2.93-3.05%, the mass percentage of copper (Cu) is 1.27-2.34%, and the mass percentage of zirconium (Zr) is 0.175-0.193 %, the balance is aluminum and a small amount of impurity elements. The copper (Cu) is copper (Cu) in the master alloy Al-Cu, and the zirconium (Zr) is zirconium (Zr) in the master alloy Al-Zr.

The mass percentage of Cu in the master alloy Al-Cu is 50.12%, and the mass percentage of zirconium (Zr) in the master alloy Al-Zr is 4.11%.

The second technical solution of the present invention is:

A method for preparing a high-hardness 89-104mm hardenable as-cast aluminum alloy, characterized in that it sequentially comprises: (1) alloy melting and casting; (2) homogenization treatment; (3) solution treatment; (4) aging deal with.

The alloy melting and casting: the process is to first melt pure Al as a molten pool, then raise the furnace temperature to 850±10°C, and then add Al-Cu, Al-Zr and Al-Sr master alloys with higher melting points. After melting, cool down to 800±10°C, stir and add pure Zn with lower melting point, stir and degas it after melting, add pure Mg wrapped with aluminum foil (reduce burning loss), and cool down to 750±10°C after melting Carry out refining, use C ₂ Cl ₆ to degas and remove slag, and cast it after standing for 15 minutes. Slag skimming was performed before casting, and the mold was preheated (at a temperature of 300°C).

The homogenization treatment is characterized in that the process is 400±5℃×6h+420±5℃×6h

+440±5℃×6h+460±5℃×12h.

Said solution treatment: characterized in that its process is 470±10℃×2h (water quenching);

The aging treatment is characterized in that the aging process adopts T6 aging: 121℃×24h.

The high hardness 89-104mm hardenable as-cast aluminum alloy can be obtained and the preparation method thereof.

Beneficial effects of the present invention:

The aluminum alloy of the present invention has a hardenability of 89-104 mm.

The invention breaks the technical blockade of high-performance aluminum alloy in foreign countries to a certain extent, and can meet the needs of my country's aerospace, weaponry and other fields.

Description of drawings

FIG. 1 is a graph showing the change of end quenching hardness and electrical conductivity in Example 1 of the present invention.

Fig. 2 is a graph showing the change of end quenching hardness and electrical conductivity in the second embodiment of the present invention.

FIG. 3 is a graph showing the change of end quenching hardness and electrical conductivity in Example 3 of the present invention.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and embodiments.

Example 1

As shown in Figure 1.

A high-hardness 89-104mm hardenable as-cast aluminum alloy, the preparation method of which is as follows:

Take 28kg aluminum alloy as an example.

According to the composition of Al-11.99Zn-3.05Mg-1.27Cu-0.193Zr, 22.04kg of pure Al (composition: 99.79% Al, 0.14% Fe, 0.04% Si, all components in the present invention are expressed in mass percentages , the same below, where the components add up to less than 100% are impurities) melted as a molten pool, then the furnace temperature was raised to 850±10°C, and 0.71kgAl-Cu (49.62%Al, 50.12%Cu, 0.15 %Fe, 0.11%Si) master alloy (the loss rate of Cu is about 6.25%) and 1.047kg Al-Zr master alloy (95.69% Al, 4.11% Zr, 0.20% Fe, 0.10% Si) (the loss rate of Zr is about 8%), cool down to 800±10°C after melting, stir and add pure Zn with a lower melting point, the mass of Zn is 3.36kg (the loss rate of Zn is about 8%), after it is melted, stirred and degassed Add pure Mg wrapped with aluminum foil (to reduce burning loss), the mass of Mg is 0.84kg (the loss rate of Mg is about 20%), after melting, it is cooled to 750±10 ° C and refined, and C ₂ Cl ₆ is used to remove The slag was removed by gas, and the casting was carried out after standing for 15 minutes. Slag removal is carried out before casting, and the mold is preheated (temperature is 300℃) to homogenize the alloy. The process is 400±5℃×6h+420±5℃×6h+440±5℃×6h+460±5 ℃×12h; the solution process is 470±10℃×2h (water quenching), and the aging process adopts T6 aging: 121℃×24h; that is, a high hardness 89-104mm hardenable cast aluminum alloy is obtained.

The measured hardness of the aluminum alloy in this embodiment is 223.75HV, the as-cast end quenching and hardening depth is 89.14mm (Fig. 2), the elongation is 8.3%, and the electrical conductivity is 29.522% IACS.

Embodiment 2

as shown in picture 2.

A high-hardness 89-104mm hardenable as-cast aluminum alloy, the preparation method of which is as follows:

Take 28kg aluminum alloy as an example.

According to the composition of Al-11.26Zn-2.84Mg-2.34Cu-0.18Zr, 21.69kg of pure Al (composition: 99.79% Al, 0.14% Fe, 0.04% Si, all components in the present invention are expressed in mass percentages , the same below, where the components add up to less than 100% are impurities) melted as a molten pool, then the furnace temperature was raised to 850±10°C, and 1.31kg Al-Cu (49.62% Al, 50.12% Cu, 0.15 %Fe, 0.11%Si) master alloy (the loss rate of Cu is about 6.25%) and 1.06kg Al-Zr master alloy (95.69% Al, 4.11% Zr, 0.20% Fe, 0.10% Si) (the loss rate of Zr is about 8%), cool down to 800±10°C after melting, stir and add pure Zn with a lower melting point, the mass of Zn is 3.15kg (the loss rate of Zn is about 8%), after it is melted, stirred and degassed Add pure Mg wrapped with aluminum foil (to reduce burning loss), the mass of Mg is 0.80kg (the loss rate of Mg is about 20%), after melting, it is cooled to 750±10 ° C and refined, and C ₂ Cl ₆ is used to remove The slag was removed by gas, and the casting was carried out after standing for 15 minutes. Slag removal is carried out before casting, and the mold is preheated (temperature is 300℃) to homogenize the alloy. The process is 400±5℃×6h+420±5℃×6h+440±5℃×6h+460±5 ℃×12h; the solution process is 470±10℃×2h (water quenching), and the aging process adopts T6 aging: 121℃×24h; that is, a high hardness 89-104mm hardenable cast aluminum alloy is obtained.

The measured hardness of the aluminum alloy in this embodiment is 219.47HV, the as-cast end quenching and hardening depth is 104 mm (Fig. 2), the elongation is 7.6%, and the electrical conductivity is 30.275% IACS.

Embodiment 3

As shown in Figure 3.

A high-hardness 89-104mm hardenable as-cast aluminum alloy, the preparation method of which is as follows:

Take 28kg aluminum alloy as an example.

According to the composition of Al-9.47Zn-2.93Mg-2.31Cu-0.175Zr, 22.25kg of pure Al (composition: 99.79% Al, 0.14% Fe, 0.04% Si, all components in the present invention are expressed in mass percentages , the same below, where the components add up to less than 100% are impurities) melted as a molten pool, then the furnace temperature was raised to 850 ± 10 ° C, and 1.29 kg Al-Cu (49.62% Al, 50.12% Cu, 0.15 %Fe, 0.11%Si) master alloy (the loss rate of Cu is about 6.25%) and 0.98kg Al-Zr master alloy (95.69% Al, 4.11% Zr, 0.20% Fe, 0.10% Si) (the loss rate of Zr is about 8%), cool down to 800±10°C after melting, stir and add pure Zn with a lower melting point, the mass of Zn is 2.65kg (the loss rate of Zn is about 8%), after it is melted, stirred and degassed Add pure Mg wrapped with aluminum foil (reduce burning loss), the mass of Mg is 0.82kg (the loss rate of Mg is about 20%), after melting, it is cooled to 750±10 ° C and refined, and C ₂ Cl ₆ is used to remove The slag was removed by gas, and the casting was carried out after standing for 15 minutes. Slag removal is carried out before casting, and the mold is preheated (temperature is 300℃) to homogenize the alloy. The process is 400±5℃×6h+420±5℃×6h+440±5℃×6h+460±5 ℃×12h; the solution process is 470±10℃×2h (water quenching), and the aging process adopts T6 aging: 121℃×24h; that is, a high hardness 89-104mm hardenable cast aluminum alloy is obtained.

The measured hardness of the aluminum alloy in this embodiment is 216.60HV, the as-cast end quenching and hardening depth is 94.81mm (Fig. 3), the elongation is 7.7%, and the electrical conductivity is 30.535% IACS.

The parts not involved in the present invention are the same as or can be implemented by using the prior art.

Claims (1)

1. A high hardness 89-104mm hardenable as-cast 7000 series aluminum alloy, which is mainly composed of aluminum (Al), zinc (Zn), magnesium (Mg), copper (Cu) and zirconium (Zr), wherein, The mass percentage of zinc (Zn) is 9.47-11.99%, the mass percentage of magnesium (Mg) is 2.93-3.05%, the mass percentage of copper (Cu) is 1.27-2.34%, and the mass percentage of zirconium (Zr) is 0.175-0.193 %, the balance is aluminum and a small amount of impurity elements, characterized in that the aluminum alloy is prepared by the following method, characterized in that it sequentially includes: (1) alloy casting; (2) homogenization treatment; (3) Solution treatment; (4) aging treatment; The alloy melting and casting: first, the raw materials are industrial pure Al, industrial pure Zn, industrial pure Mg, industrial Al-50.12%Cu, Al-4.11%Zr master alloy; Degassing and impurity removal. During the smelting process, pure Al is first melted as a molten pool, and then the furnace temperature is raised to 850±10 ^o C, and then Al-50.12%Cu and Al-4.11%Zr master alloys are added. After melting Cool down to 800 ± 10 ^o C, stir and add pure Zn with a lower melting point, after it is melted, stir and degas, add pure Mg wrapped with aluminum foil, and after melting, cool down to 750 ± 10 ^o C and carry out refining, using C ₂ Cl ₆ is degassed and slag removed, cast after standing for 15 min, slag removal is performed before casting, and the mold is preheated to 300 ^o C; The homogenization treatment: the process is 400±5℃×6h+420±5℃×6h+440±5℃×6h+460±5℃×12h; The solution treatment: the process is 470 ± 10 ^o C × 2 h, water quenching; The described aging treatment: the process is that the aging process adopts T6 aging: 121 ^o C × 24 h; After the above steps, a high hardness 89-104mm hardenability 7000 series aluminum alloy can be obtained.

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