WO2017215104A1

WO2017215104A1 - Super-high strength non-rapidly solidified aluminum alloy and preparation method therefor

Info

Publication number: WO2017215104A1
Application number: PCT/CN2016/094819
Authority: WO
Inventors: 许晓静; 朱金鑫; 丁清; 吴瑶; 孙良省; 谈成; 张香丽; 赵建吉; 杨帆; 杜东辉
Original assignee: 江苏大学
Priority date: 2016-06-16
Filing date: 2016-08-12
Publication date: 2017-12-21
Also published as: CN105908029A; CN105908029B

Abstract

Provided is a 770 Mpa-level super-high strength non-rapidly solidified aluminum alloy, wherein same comprises zinc at 8.8-9.4 wt%, magnesium at 2.75-2.85 wt%, copper at 1.8-2.2 wt%, zirconium at 0.25-0.55 wt%, strontium at 0-0.025 wt%, and the balance is aluminum; and the ratio of the mass percent of Zn and that of Mg in the alloy elements should satisfy 3 ≤ WtZn/WtMg ≤ ４, and the mass percent of Mg, i.e. WtMg, should satisfy 2% ≤ WtMg ≤ 3%. The alloy is prepared and obtained by means of fusion casting-homogenizing annealing-hot extrusion-solid solution treatment-aging treatment.

Description

Ultra high strength non-rapid solidified aluminum alloy and preparation method thereof

Technical field

The invention belongs to the field of metal alloys, in particular to a 770MPa grade ultra high strength non-rapid solidified aluminum alloy and a preparation method thereof.

Background technique

Aluminum alloy is a typical lightweight material with low density, high strength, good toughness, corrosion resistance, easy processing, easy recycling, low manufacturing cost, strong foundational industrial strength, good military-civilian integration, etc. Or the leap-forward improvement of a certain important single item performance has played a very strong supporting role for the development of advanced equipment in different periods. For a long time, the development of aluminum alloy with higher strength level and more balanced performance has been a very important research topic. It is related to a country's aerospace, weaponry, general industry, resource conservation, environmental protection and many other fields. The level of development has always been one of the most competitive areas of science and technology in the world.

In the mid-1990s, developed countries successfully developed a 750 MPa high-strength aluminum alloy by spray forming rapid solidification technology. The typical alloy is RSA7034 (Al-11Zn-2.3Mg-1Cu), which is among the best in the world. However, the spray forming rapid solidification technique makes it difficult to prepare a large ingot aluminum alloy, and the price is high, which limits its application.

Chinese patent CN101338391 discloses a rapid solidification block aluminum alloy with high strength and high ductility and a preparation method thereof, but the rapid solidification block aluminum alloy has high strength, but the preparation process is spray forming rapid solidification technology, and the cost is high. And this technology can only prepare millimeter-scale bulk aluminum alloy, which can hardly be applied to actual production.

Chinese patent CN102127665 discloses an Al-Zn-Mg-Cu-Sc-Zr-RE alloy which can be used as an ultra-high-strength cast aluminum alloy and a preparation method thereof, wherein RE is a rare metal element such as Er or Yb. The elements are rare earth metal elements, the price is relatively expensive, and the raw material cost is high. At the same time, the maximum tensile strength of the aluminum alloy prepared by this method can reach 605 MPa, and there is no substantial breakthrough compared with the international advanced level.

Chinese patent CN103993211 discloses a 720-750MPa ultra-high strength non-rapid solidified aluminum alloy and a preparation method thereof. The strength of the aluminum alloy can reach 720-750 MPa, but the patent only gives the composition of the alloy, and the content of the main alloy element The relationship between the two is not limited, and has certain limitations, and the alloy needs to be subjected to melt casting-homogenization annealing-hot extrusion-pre-reduction annealing-solution treatment-pre-deformation-aging treatment. The process is relatively cumbersome, which is not conducive to industrial production, and some of these processes still have room for optimization.

So far, there is no 770MPa grade ultra-high strength non-rapid solidified aluminum alloy with independent intellectual property rights and its preparation method, which restricts the development of China's aerospace, weaponry and other industries to some extent.

Summary of the invention

The object of the present invention is to design a 770 MPa ultra-high strength non-rapid solidified aluminum alloy and a preparation method thereof by component design and preparation technology design.

The technical solution of the present invention is:

A 770 MPa ultra-high strength non-rapid solidified aluminum alloy characterized by: aluminum alloy (Al), zinc (Zn), magnesium (Mg), copper (Cu), zirconium (Zr) and strontium (Sr) The composition, wherein the mass percentage of zinc (Zn) is 8.8 to 9.4%, the mass percentage of magnesium (Mg) is 2.75 to 2.85%, the mass percentage of copper (Cu) is 1.8 to 2.2%, and the mass of zirconium (Zr) The percentage is 0.25 to 0.55%, the mass percentage of strontium (Sr) is 0 to 0.025%, and the balance is aluminum, and only the ratio of the mass percentage of Zn and Mg in the alloying element is satisfied to satisfy 3 ≤ Wt _Zn / Wt _Mg ≤ 4, Wt _Mg Mg percentage of quality to meet the 2% ≤Wt _Mg ≤3%, in order to make major ZnMg strengthened alloy phase to achieve maximum strengthening effect.

The invention discloses a preparation method of 770MPa grade ultra high strength non-rapid solidified aluminum alloy, which is characterized in that it comprises: melting casting - homogenization annealing - hot extrusion - solution treatment - aging treatment.

The casting: the process is based on the composition design, weighing each raw material, wherein Cu, Zr, Sr three elements are added using Al-Cu, Al-Zr, Al-Sr intermediate alloy, Al, Zn, Mg are used Elemental, the specific order of smelting is to first weigh the well-prepared Al, Zn, Al-Cu, Al-Zr, Al-Sr in a melting furnace, the melting temperature is 900 ° C, after the five raw materials are melted with titanium The alloy rod is evenly stirred, allowed to stand for 3 min, and then de-evaporated by adding hexachloroethane and argon until no gas escapes. In order to reduce the burning loss of Mg during smelting, the furnace temperature is lowered to 800 ° C, and then Mg is added. Mg should be wrapped in aluminum foil. In order to prevent the low density of Mg, float on other liquid alloys, press the titanium alloy container into the bottom of the liquid alloy, let stand for 5 minutes, stir with titanium rod, then add hexachloroethane and argon. Refined degassing until no gas escapes, then raise the furnace temperature to 850 ° C, keep warm for 10 min, and finally cast into ingots.

The homogenization annealing is characterized in that the annealing mechanism is 420 ° C × 6 h + 440 ° C × 6 h + 460 ° C × 6 h + 465 ° C × 12 h, and the annealing end temperature is higher, so that the composition inside the alloy is more uniform.

The hot extrusion is characterized in that the process is to heat the alloy after homogenization annealing to 480 ° C and hold for 8 hours, and then perform extrusion with a compression ratio of 10:1, and the moderate extrusion ratio can be reduced. The generation of internal defects in the alloy.

The solution treatment is characterized in that the solid solution mechanism is 450 ° C × 2 h + 460 ° C × 2 h + 470 ° C × 2 h after the room temperature water quenching, the water quenching transfer time does not exceed 10 s.

The aging treatment is characterized in that the process is T6 aging, and the aging mechanism is 121 ° C × 24 h.

An ultra-high strength non-rapid solidified aluminum alloy of 770 MPa grade can be obtained.

The beneficial effects of the invention:

(1) The present invention obtains a composition of a 770 MPa ultra-high strength non-rapidly solidified aluminum alloy and a preparation method thereof. Compared with the disclosed patent, the composition is clearly distinguished, and the composition interval is more precise, and the alloy is clearly given. The relationship between the content of major alloying elements is more scientific and reasonable in process, especially smelting, homogenization annealing and hot extrusion Process, more scientific component design and process optimization together improve the strength of the aluminum alloy. Moreover, the process is obviously simplified as a whole, laying the foundation for industrialization.

(2) The composition of the 770 MPa ultra-high strength non-rapidly solidified aluminum alloy obtained by the invention and the preparation method thereof, the alloy has high strength, and the elongation can still be maintained above 7%, and the existing rapid forming technology of spray forming can only Compared with the manufacture of millimeter-sized block-shaped aluminum alloys, the present technology is capable of producing larger high-strength aluminum alloy products, and is more valuable for use.

detailed description

The invention will now be further described in conjunction with specific embodiments.

Embodiment 1

Preparation of 770MPa grade ultra-high strength non-rapid solidified aluminum alloy Al-9.01Zn-2.79Mg-2.14Cu-0.52Zr-0.025Sr, Wt _Zn /Wt _Mg =3.23, and Wt _Mg =2.79%, satisfying 3≤Wt _Zn /Wt _Mg ≤ 4, ₂ % ≤ Wt _Mg ≤ 3%, the preparation process is as follows:

(1) Melting and casting: According to the above composition design, each raw material is weighed, wherein Cu, Zr and Sr are added by using Al-Cu, Al-Zr and Al-Sr intermediate alloys, and Al, Zn and Mg are used as simple substances. The specific sequence of smelting is to first weigh the well-prepared Al, Zn, Al-Cu, Al-Zr, Al-Sr in a melting furnace, and the melting temperature is 900 ° C. After the five raw materials are melted, the titanium alloy rod is used. Stir well, let stand for 3min, then add hexachloroethane and argon to refine the gas until no gas escapes. In order to reduce the burning loss of Mg during smelting, reduce the furnace temperature to 800 °C, then add Mg, and Mg Wrapped in aluminum foil, in order to prevent the low density of Mg, float on other liquid alloys, press the titanium alloy container into the bottom of the liquid alloy, let stand for 5 minutes, stir with titanium rod, then add hexachloroethane and argon to remove Gas until no gas escapes, then raise the temperature of the furnace to 850 ° C, keep warm for 10 min, and finally cast into an ingot.

(2) Homogenization annealing: The ingot obtained in the previous step is subjected to homogenization annealing, and the annealing mechanism is 420 ° C × 6 h + 440 ° C × 6 h + 460 ° C × 6 h + 465 ° C × 12 h.

(3) Hot extrusion: The alloy after homogenization annealing was heated to 480 ° C and held for 8 hours, and then extruded at a compression ratio of 10:1 to obtain an extruded bar.

(4) Solution treatment: The solution bar obtained in the previous step is solution treated, and the solution mechanism is 450 ° C × 2 h + 460 ° C × 2 h + 470 ° C × 2 h after heat preservation at room temperature, the water quenching transfer time is not More than 10s.

(5) Aging treatment: The solution treated by the solution obtained in the previous step was subjected to T6 aging treatment, and the aging mechanism was 121 ° C × 24 h.

After the above steps, the aluminum alloy was obtained, and the tensile strength of the alloy was measured to be 770.1 MPa and the elongation was 8.2%.

Embodiment 2

Preparation of 770MPa grade ultra-high strength non-rapid solidified aluminum alloy Al-9.34Zn-2.84Mg-2.17Cu-0.29Zr-0.025 Sr, Wt _Zn /Wt _Mg =3.29, and Wt _Mg =2.84%, satisfying 3≤Wt _Zn /Wt _Mg ≤ 4, ₂ % ≤ Wt _Mg ≤ 3%, the preparation process is the same as that in the first embodiment. The aluminum alloy obtained in this example has the highest tensile strength of 780.8 MPa and an elongation of 7 after strength tensile test. %.

Embodiment 3

Preparation of 770MPa grade ultra-high strength non-rapid solidified aluminum alloy Al-8.89Zn-2.82Mg-1.85Cu-0.31Zr-0.025Sr, Wt _Zn /Wt _Mg =3.15, and Wt _Mg =2.82%, satisfying 3≤Wt _Zn /Wt _Mg ≤ 4, ₂ % ≤ Wt _Mg ≤ 3%, the preparation process is the same as that of the first embodiment. The tensile strength of the aluminum alloy obtained in this example is 776.4 MPa and the elongation is 7.8%. .

Those skilled in the art can appropriately adjust the ratio of each component according to the above examples and manufacture according to the above steps to obtain an ideal 770 MPa grade ultra high strength non-rapid solidified aluminum alloy and a preparation method thereof.

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

Claims

An ultra-high strength non-rapidly solidified aluminum alloy having a tensile strength of not less than 770 MPa and an elongation of more than 7%, the composition of the aluminum alloy being composed of aluminum (Al), zinc (Zn) , magnesium (Mg), copper (Cu), zirconium (Zr) and strontium (Sr) composition, characterized in that the mass percentage of zinc (Zn) is 8.8 to 9.4%, and the mass percentage of magnesium (Mg) is 2.75 - 2.85%, the mass percentage of copper (Cu) is 1.8 to 2.2%, the mass percentage of zirconium (Zr) is 0.25 to 0.55%, the mass percentage of strontium (Sr) is 0 to 0.025%, and the balance is aluminum, and the alloying elements are The ratio of the mass percentage of Zn and Mg should satisfy 3 ≤ Wt Zn /Wt Mg ≤ 4, and the mass percentage of Mg Wt Mg should satisfy 2% ≤ Wt Mg ≤ 3%.
The method for preparing an ultra-high strength non-rapidly solidified aluminum alloy according to claim 1, wherein the steps include: casting-homogeneous annealing-hot extrusion-solution treatment-aging treatment, wherein:

The process of casting is as follows: according to the composition design, each raw material is weighed, wherein the three elements of Cu, Zr and Sr are added by using Al-Cu, Al-Zr, Al-Sr intermediate alloy, Al, Zn and Mg. The use of simple substances, the specific order of smelting is to first weigh the well-prepared Al, Zn, Al-Cu, Al-Zr, Al-Sr in a melting furnace, the melting temperature is 900 ° C, after the five raw materials are melted The titanium alloy rod is evenly stirred, left to stand for 3 min, and then de-evaporated by adding hexachloroethane and argon until no gas escapes. In order to reduce the burning loss of Mg during smelting, the furnace temperature is lowered to 800 ° C, and then Mg is added. And Mg is wrapped with aluminum foil. In order to prevent the low density of Mg, float on other liquid alloys, press Mg into the bottom of the liquid alloy with a titanium alloy container, let stand for 5 minutes, stir with titanium rod, and then add hexachloroethane. And argon refining degassing until no gas escapes, then raise the furnace temperature to 850 ° C, keep warm for 10 min, and finally cast into ingot;

The homogenization annealing: annealing mechanism is 420 ° C × 6h + 440 ° C × 6h + 460 ° C × 6h + 465 ° C × 12h;

The hot extrusion is carried out by heating the alloy after homogenization annealing to 480 ° C and holding it for 8 hours, and then performing extrusion with a compression ratio of 10:1.
A method for preparing an ultra-high-strength non-rapidly solidified aluminum alloy according to claim 2, wherein: said solution treatment, the solution mechanism is 450 ° C × 2 h + 460 ° C × 2 h + 470 ° C × 2 h After heat preservation, the water is quenched at room temperature, and the water quenching transfer time does not exceed 10 s.
The method for preparing an ultra-high-strength non-rapidly solidified aluminum alloy according to claim 2, wherein: said aging treatment is characterized in that the process is T6 aging, and the aging mechanism is 121 ° C × 24 h;