Heat treatment method for pre-aging, re-solid-solution and re-aging of Al-Cu-Li alloy

Abstract

The invention discloses a heat treatment method for pre-aging, re-solid-solution and re-aging of an Al-Cu-Li alloy, belongs to the field of material heat treatment, and aims to perform conventional solid-solution, pre-aging, re-solid-solution and re-aging treatment on an Al-Cu-Li alloy extruded plate by controlling a heat treatment process system and parameters thereof. The conventional solid solution and re-solid solution treatment temperature is 515 +/-10 DEG C, heat preservation is performed for 60-90 min, then water quenching is performed, and the quenching transfer time is shorter than 5s. The pre-aging and re-aging treatment temperature is 160-180 DEG C, heat preservation is performed for 24-48 hours, and the product is taken out for air-cooling. The strength of the alloy can be reduced through re-solid-solution treatment, the plasticity of the alloy is improved, and correction and reprocessing processes are facilitated. The re-aging treatment can effectively regulate and control the variety, density and distribution of precipitated phases, thereby enhancing the strength of the alloy. In addition, due to coarsening of discontinuous grain boundary precipitated phases in the alloy and increasing of the copper content, on the premise that the strength of the alloy is basically not lost, the stress corrosion resistance, the intergranular corrosion resistance and the electrochemical corrosion resistance are improved, and the plasticity of the alloy is improved. The process is simple and feasible and is not limited by the thickness of the plate.

Description

technical field [0001] The invention relates to a heat treatment method for Al-Cu-Li alloy pre-aging heavy solution re-aging, which belongs to the technical field of metal material heat treatment, in particular to the technical field of aluminum alloy heat treatment. Background technique [0002] The information disclosed in this background section is only intended to increase the understanding of the general background of the present invention, and is not necessarily taken as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to those skilled in the art. [0003] As an emerging lightweight alloy material, Al-Cu-Li alloy has been favored for its high elastic modulus, high specific strength and specific stiffness, high damage tolerance, low density, and good weldability. Widely used in aviation, aerospace and military fields, it has become the main substitute material for 2xxx and 7xxx series aluminum alloys. [0004] Al-...

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Problems solved by technology

However, the inventors found that the alloy used in this research has undergone pre-stretch deformation treatment, and the alloy has been subjected to pre-stretch deformation again during the re-aging process. Although the performance of the alloy can be improved, in the actual application process, the pre-deformation will change. The initial shape of the structural parts affects the dimensional accuracy of the structural parts, which may make the structural parts unusable, so the aging treatment system is not practical for structural parts in practical applications

In addition, the aging system does not indicate its role in balancing the strength and corrosion resistance of the alloy, and does not analyze and study the stress corrosion resistance and electrochemical corrosion resistance of the alloy after the process, nor does it give information about the crystal Mechanistic Explanation of the Characteristic Evolution of Boundary Precipitated Phases

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