High-damage tolerance type ultrahigh strength aluminum alloy and preparation method thereof

Abstract

The invention relates to a high-damage tolerance type ultrahigh strength aluminum alloy and a preparation method thereof. The high-damage tolerance type ultrahigh strength aluminum alloy comprises the following components in percentage by weight: 8.5-10.0 percent of Zn, 1.0-2.5 percent of Mg, 1.0-2.0 percent of Cu, 0.06-0.20 percent of Zr, 0.02-0.05 percent of Ti, not more than 0.08 percent of Fe, not more than 0.06 percent of Si and the balance of Al and unavoidable impurities, wherein the Fe content is larger than Si content. The method comprises the following steps: firstly, smelting and casting; then carrying out homogenization on an alloy casting blank by stages, carrying out hot rolling on the homogenized casting blank and carrying out solid dissolution on a hot rolled plate; prestretching the plate in four hours after quenching; and finally immediately carrying out double-stage ageing processing on the prestretched plate. The obtained alloy has higher strength and damage tolerance and is suitable for being applied in an airplane part exposed in the atmospheric environment for a long time.

Description

technical field [0001] The invention relates to a high-damage-tolerant ultra-high-strength aluminum alloy and a preparation process thereof, belonging to the technical field of non-ferrous metals. Background technique [0002] Ultra-high-strength aluminum alloy has the advantages of low density, high strength, and good thermal processing performance, and is an important structural material in the aerospace field. With the development of the aerospace industry, the requirements for aircraft structural materials are no longer at the initial stage of only pursuing high static strength or high corrosion resistance, but have developed to an urgent need to develop new ultra-high-strength aluminum alloy materials with excellent comprehensive properties. stage, that is, it is required that the new ultra-high-strength aluminum alloy material should not only have high strength, but also have good fracture toughness, good corrosion resistance and good fatigue performance, that is, it s...

AI Technical Summary

Problems solved by technology

Although aluminum alloys such as AA7150, AA7449, and AA7055 have high strength and good corrosion resistance, their fracture toughness is low, which affects the service life of the aircraft

Although the AA 7085 aluminum alloy has high fracture toughness and good corrosion resistance, its strength is relatively low, which also reduces the safety factor of the aircraft

The reasons are: (1) The content of Zn, Mg and other elements in the alloy is low, and the main strengthening phase MgZn 2 The amount formed is small, so the strength of the alloy is low; (2) the content of Cu, Mg and other elements in the alloy is high, and it is easy to form a high melting point, which is difficult to dissolve in the solid solution process. 2 CuMg) phase, so the damage tolerance performance of the alloy is low, especially the fracture toughness is low