Preparing method for 700-MPa-level aluminum alloy extruded section

Abstract

The invention provides a preparing method for a 700-MPa-level aluminum alloy extruded section. The 700-MPa-level aluminum alloy extruded section is prepared from, by weight percentage, 7.8% to 10.3% of Zn, 1.3% to 2.0% of Mg, 1.3% to 2.0% of Cu, 0.08% to 0.15% of Zr, smaller than or equal to 0.15% of Si, smaller than or equal to 0.15% of Fe, smaller than or equal to 0.15% of other impurities and the balance Al, wherein the weight percentage of each kind of the impurities is smaller than or equal to 0.05%. The preparing method includes the steps that the raw materials are prepared according to alloy components, fused, subjected to furnace refining and standing, and then cast into an alloy ingot with the required specification; and the alloy ingot is subjected to preferred three-stage homogenizing, then formed through a preferred extrusion technology and can be used for part machining after heat treatment. The novel aluminum alloy extruded section is even in microscopic structure and stable in performance, and the ultimate tensile strength can be higher than 700 MPa; and meanwhile elongation is higher than 8%, fracture toughness is higher than 26 MPa.m<1 / 2>, the current aerospace material selecting requirement is met, and meanwhile the aluminum alloy extruded section can be widely applied to the fields of the nuclear industry, transportation, weapons and the like.

Description

technical field [0001] The invention relates to an aluminum alloy extruded profile, in particular to a preparation method for a 700MPa grade aluminum alloy extruded profile. Background technique [0002] In recent years, with the improvement of aluminum metallurgical equipment technology and metallurgical basic technology, high purification and high alloying have made it possible to manufacture 600MPa aluminum alloys through traditional melting and casting technology, and have been industrialized. Aluminum alloys include 7150 aluminum alloy (Al-7.6%Zn-1.8%Mg-2.0%Cu-0.10%Zr), 7055 aluminum alloy (Al-8%Zn-2.0%Mg-2.2%Cu-0.10%Zr) and the like. [0003] At present, the powder metallurgy method can also produce aluminum alloys above 700MPa, or even 800MPa, but it is difficult for industrial application due to various conditions. At present, some domestic patent documents can also produce aluminum alloys above 700MPa by adding high-content Zn elements and T77 three-stage aging pro...

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Problems solved by technology

[0003] At present, the powder metallurgy method can also produce aluminum alloys above 700MPa, or even 800MPa, but it is difficult for industrial application due to various conditions.

At present, some domestic patent documents can also produce aluminum alloys above 700MPa by adding high-content Zn elements and T77 three-stage aging process. If the Zn content exceeds 10%, there is a problem that the ingot is easy to crack and difficult to form. Realize industrial application

In addition to the difficulty of ingot forming in high alloying, a lot of coarse non-equilibrium eutectic phases will be formed in the grain and grain boundaries. It is difficult to completely eliminate them by traditional homogenization and solid solution processes, and it is also difficult to obtain alloy properties. big improvement

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