CN110172624A - A kind of high tough aluminum alloy forge piece and preparation method thereof - Google Patents

Abstract

The invention relates to a high-strength and tough aluminum alloy forging and a preparation method thereof. The alloy composition is: Zn10.0%-11.0%, Mg2.7%-3.2%, Cu 1.8%-2.2%, Zr0 .04%～0.20%, Sc0.10%～0.20%, Mn 0.10%～0.60%, Si≤0.08%, Fe≤0.10%, Ti≤0.10%, other impurities individually≤0.05%, total≤0.15%, The balance is Al. The ingredients are distributed according to the alloy composition, the raw materials are melted, refined in the furnace, and after standing still, the alloy ingot is made by rapid solidification and spray forming. The alloy ingot is homogenized and formed by forging. After quenching, the forgings are subjected to peak aging heat treatment, and the peak aging is 90°C/10h~24h+135°C/10h~30h. A new type of ultra-high-strength and high-toughness aluminum alloy material of the present invention has uniform microstructure and stable performance, the ultimate tensile strength can reach more than 840 MPa, and at the same time, the elongation rate is higher than 10%, and the fracture toughness in the T-L direction can reach 29 MPam ^1/2 . The material product can be used for structural elements in the fields of aerospace, nuclear industry, transportation, sporting goods, weapons and the like.

Description

A kind of high strength and toughness aluminum alloy forging and preparation method thereof

Field

The invention relates to a novel Al-Zn-Mg-Cu series high-strength aluminum alloy forging and a preparation method thereof, belonging to the field of metal material engineering. The new aluminum alloy product produced by the method has excellent strength and fracture toughness, and its ultimate tensile strength can reach more than 840MPa, while the elongation is higher than 10%, and the fracture toughness in TL direction can reach more than 29MPam ^1/2 . The material product can be used for structural elements in the fields of aerospace, nuclear industry, transportation, sporting goods, weapons and the like.

Background technique

In recent years, with the improvement of aluminum metallurgical equipment technology and basic metallurgical technology, the development trend of aluminum alloys is high purity, high performance and high alloying. 800MPa grade aluminum alloy. The invention is an ultra-high-strength and high-toughness aluminum alloy. It adopts high magnesium and high zinc ratios, and simultaneously adds Zr and Sc elements to realize composite microalloying. The precipitated phase is dispersed and uniform through a low-temperature primary pre-aging method, and multi-stage Peak aging or multi-stage overaging process, the tensile strength of the aluminum alloy of the present invention can reach more than 840MPa, and the TL direction can reach more than 29MPam ^1/2 of the high-strength and high-toughness aluminum alloy, which is used in aerospace, nuclear industry, transportation, and sporting goods , weapons and other fields have broad application prospects.

Contents of the invention

The purpose of the present invention is to provide a preparation method for a novel high-strength and high-toughness aluminum alloy. It belongs to the field of metal material engineering.

Technical scheme of the present invention is as follows:

A 7000-series high-strength and tough aluminum alloy forging, the composition weight percentage of the 7000-series aluminum alloy material is: Zn 10.0%-11.0%, Mg 2.8%-3.2%, Cu 1.8%-2.2%, Zr 0.04%-0.20 %, Sc 0.10%～0.20%, Si≤0.08%, Fe≤0.10%, Ti≤0.10%, other impurities individually≤0.05%, total impurities≤0.15%, and the balance is Al.

Preferably, the content percentage of Zn element is: Zn10.5%˜11.0%.

Preferably, the content percentage of Mg element is: Mg3.0%～3.2%.

Preferably, Zr and Sc elements are micro-alloyed by Zr and Sc composites, and the content percentages of Zr and Sc elements are: Zr 0.08%-0.20%, Sc 0.15%-0.20%.

A method for preparing a 7000-series high-strength and tough aluminum alloy forging. Homogenizing a 7000-series aluminum alloy ingot in a heating furnace includes the following steps: performing homogenization on a 7000-series aluminum alloy ingot in a heating furnace. The homogenization process It is carried out in two stages. The homogenization temperature of the first stage is 410°C-430°C, and the holding time is 6 hours; the homogenization temperature of the second stage is 460°C-480°C, and the holding time is more than 36 hours.

The specific preparation process of the 7000 series high-strength and toughness aluminum alloy forging is as follows:

(1) According to the composition weight percentage requirements of 7000 series aluminum alloy;

(2) The preparation of 7000 series aluminum alloy ingots adopts the process of rapid solidification spray forming, and the process is carried out according to the conventional process of 7075 and other alloys;

(3) Homogenize the 7000 series aluminum alloy ingot in the heating furnace;

(4) After the homogenization treatment, the 7000 series aluminum alloy ingot is stripped and forged, and the forging process is carried out according to the conventional process of 7075 alloy;

(5) 7000 series aluminum alloy forgings are quenched after solution treatment, and the solution temperature is 470 ° C ~ 480 ° C;

(6) After quenching, the 7000 series aluminum alloy forgings are subjected to peak aging heat treatment, and then processed into required parts. The peak aging is 90°C/10h~24h+135°C/10h~30h.

Preferably, the peak aging process parameter in step (6) is: 110°C-175°C/not lower than 4h.

Preferably, the alloy overaging process parameters in step (6) are: 80°C-100°C/10h-24h+105°C-145°C/not lower than 4h+150°C-180°C/6h-30h.

The advantage of the present invention is that it is a new type of ultra-high-strength and high-toughness aluminum alloy material with uniform microstructure and stable performance. The ultimate tensile strength can reach more than 840MPa, while the elongation is higher than 10%, and the fracture toughness in the TL direction can reach ^29MPam . ^/2 . The material product can be used for structural elements in the fields of aerospace, nuclear industry, transportation, sporting goods, weapons and the like.

Detailed ways

The present invention is a 7000-series highly saturated alloy element aluminum alloy, the main alloy elements Zn and Mg form the main strengthening phase, and the other main alloy element Cu plays an auxiliary strengthening effect, and at the same time plays a role in improving the stress corrosion resistance of the alloy. The invention further improves the comprehensive performance of alloy strength and toughness by increasing the content of Zn and Mg. The study found that the increase of the Zn content to more than 9.0% will promote the damage of the alloy element Cu to the general corrosion performance of the material. For example, to maintain the high general corrosion performance of the material, the upper limit of the addition of the alloy element Cu is about 2.0%. Sc, using Sc+Zr composite microalloying technology, is to control the texture of the material, reduce anisotropy, and improve the stress corrosion performance of the material.

For the alloy of the present invention, carry out graded homogenization treatment, the first-stage homogenization temperature is 410°C-430°C, and the holding time is 6 hours, which is conducive to the dispersion and precipitation of fine Al (Sc, Zr) precipitates; the second-stage homogenization The temperature is 460°C-480°C, and the holding time is more than 36 hours, which can eliminate alloy micro-segregation.

The present invention has studied the effect of long-term aging on the type and form of the precipitated phase. The research shows that: at 90°C, the GP(I) zone is uniformly and fully precipitated, and its size increases as the temperature increases, reaching the separation between the solute atoms and the precipitated phase. equilibrium; above 105°C, the GP(II) region precipitates, and the GP(I) region precipitates rapidly, and transforms to the η' phase; above 150°C, the GP(Ⅰ) region transforms to the η' phase obviously; above 180°C, the GP The critical temperature of remelting in the zone, the behavior of the precipitated phase of the material is dominated by the transformation and remelting of the GP zone. Based on the above strengthening phase precipitation sequence, the present invention proposes a graded aging process, which can fully improve the strengthening and toughening effect of materials.

The following examples illustrate the preparation process and process control of this new type of ultra-high-strength and high-toughness aluminum alloy, so as to ensure the stability of the performance of the alloy, so that it can be better applied in the fields of aerospace, nuclear industry, transportation, sporting goods, weapons, etc. .

Example 1:

The main components of the alloy are controlled at Zn10.0%-11.0%, Mg2.8%-3.2%, Cu 1.8%-2.2%, Zr0.04%-0.20%, Sc 0.10%-0.20%. The alloy ingot was prepared by rapid solidification spray forming method, and the process was carried out according to the conventional process of 7075 and other alloys, and a φ500mm round ingot was prepared. The composition of the alloy ingot is shown in Table 1.

Table 1 Ingot Alloy Composition

Ingot No. Zn Mg Cu Zr sc Ti Fe Si 305 10.2 2.9 2.0 0.13 - ≤0.10 ≤0.10 ≤0.08 306 10.8 2.9 2.2 0.10 - ≤0.10 ≤0.10 ≤0.08 308 10.4 2.9 1.8 0.11 - ≤0.10 ≤0.10 ≤0.08 309 10.1 3.0 1.9 0.14 - ≤0.10 ≤0.10 ≤0.08 311 10.6 3.1 1.9 0.16 - ≤0.10 ≤0.10 ≤0.08 313 10.6 3.2 1.8 0.12 0.15 ≤0.10 ≤0.10 ≤0.08 318 10.8 3.0 1.9 0.12 0.16 ≤0.10 ≤0.10 ≤0.08 319 10.3 3.2 2.0 0.11 0.16 ≤0.10 ≤0.10 ≤0.08 320 10.5 2.9 2.1 0.12 1.11 ≤0.10 ≤0.10 ≤0.08 321 10.4 2.9 2.2 0.13 0.12 ≤0.10 ≤0.10 ≤0.08 323 10.2 3.0 1.9 0.13 0.13 ≤0.10 ≤0.10 ≤0.08 324 10.5 3.0 1.8 0.12 0.14 ≤0.10 ≤0.10 ≤0.08

The alloy ingot is homogenized in the heating furnace. The homogenization process is carried out in two stages. The homogenization temperature of the first stage is 420°C, and the holding time is 6 hours; the homogenization temperature of the second stage is 470°C, and the holding time is 36 hours.

The homogenized alloy ingot is peeled off and then forged into shape, and the forging process is carried out according to the conventional process of 7075 alloy.

The forgings are quenched after solution treatment, and the solution temperature is 470°C to 480°C.

After quenching, the forgings are subjected to peak aging heat treatment, and the peak aging process 1 system is: 90°C/24h+135°C/18h.

The peak aging process 2 regime is: 135°C/16h.

The alloy overaging process system is: 85°C/24h+120°C/7h+165°C/8h.

Table 2 Invention alloy forging properties

Claims (8)

1. A high-strength and tough aluminum alloy forging, characterized in that: the composition weight percentage of the 7000 series aluminum alloy forging is: Zn 10.0%-11.0%, Mg 2.8%-3.2%, Cu 1.8%-2.2%, Zr 0.04 %～0.20%, Sc 0.10%～0.20%, Si≤0.08%, Fe≤0.10%, Ti≤0.10%, other impurities individually≤0.05%, total impurities≤0.15%, and the balance is Al. 2. The high-strength and toughness aluminum alloy forging according to claim 1, characterized in that the percentage of Zn element content is: Zn10.5%-11.0%. 3. The high-strength and toughness aluminum alloy forging according to claim 1, characterized in that: the percentage of Mg element content is: Mg3.0%-3.2%. 4. The high-strength and tough aluminum alloy forging according to claim 1, characterized in that: Zr and Sc elements are micro-alloyed by Zr and Sc composites, and the element content percentages of Zr and Sc are respectively: Zr 0.08% to 0.20%, Sc 0.15 % to 0.20%. 5. The method for preparing a high-strength and tough aluminum alloy forging as claimed in claim 1, wherein the preparation process includes the step of homogenizing the 7000 series aluminum alloy ingot in a heating furnace, and the step is specifically as follows: in the heating furnace The 7000 series aluminum alloy ingots are homogenized internally. The homogenization process is carried out in two stages. The homogenization temperature of the first stage is 410℃～430℃, and the holding time is 6 hours; the homogenization temperature of the second stage is 460℃～480℃ ℃, the holding time is more than 36 hours. 6. the preparation method of high-strength and tough aluminum alloy forging as claimed in claim 5, is characterized in that, specific preparation process is as follows: (1) According to the composition weight percentage requirements of 7000 series aluminum alloy; (2) The preparation of 7000 series aluminum alloy ingots adopts the process of rapid solidification spray forming, and the process is carried out according to the conventional process of 7075 and other alloys; (3) Homogenize the 7000 series aluminum alloy ingot in the heating furnace; (4) After the homogenization treatment, the 7000 series aluminum alloy ingot is peeled off and then forged, and the forging process is carried out according to the conventional process of 7075 alloy; (5) 7000 series aluminum alloy forgings are quenched after solution treatment, and the solution temperature is 470 ° C ~ 480 ° C; (6) After quenching, the 7000 series aluminum alloy forgings are subjected to peak aging heat treatment, and then processed into required parts. The peak aging is 90°C/10h~24h+135°C/10h~30h. 7. The method for preparing high-strength and tough aluminum alloy forgings according to claim 6, characterized in that the peak aging process parameters in step (6) are: 110°C-175°C/not less than 4h. 8. The method for preparing high-strength and tough aluminum alloy forgings according to claim 6, characterized in that the alloy overaging process parameters in step (6) are: 80°C-100°C/10h-24h+105°C-145°C/no Lower than 4h+150℃～180℃/6h～30h.