2324 aluminum alloy and homogenization heat treatment method thereof

Abstract

The invention relates to a 2324 aluminum alloy and a homogenization heat treatment method thereof, and belongs to the technical field of aluminum alloy heat treatment, and the homogenization heat treatment method of the 2324 aluminum alloy comprises the steps that an aluminum alloy ingot is heated to 494-495 DEG C and then heated to 498-500 DEG C for 25-30 h, and finally the aluminum alloy ingot is air-cooled to 20-25 DEG C. According to the method, by means of slow heating at the melting temperature of the low-melting-point eutectic phase, the influence of the temperature on eutectic phase redissolution is fully exerted, redissolution of the low-melting-point eutectic phase is accelerated under the condition that it is guaranteed that the cast ingot is not overburnt, the redissolution time of theta (Al2Cu) and S (Al2CuMg) formed through non-equilibrium solidification is greatly shortened along with temperature rising, and therefore the casting quality of the cast ingot is improved. The time for homogenizing heat treatment of the aluminum alloy cast ingot is saved to a great extent, the heat treatment cost of the aluminum alloy is saved, and the machining efficiency of the aluminum alloy is improved.

Description

technical field [0001] The invention belongs to the technical field of aluminum alloy heat treatment, and relates to a 2324 aluminum alloy and a homogenization heat treatment method thereof. Background technique [0002] 2324 aluminum alloy is an Al-Cu-Mg alloy, which is a 2xxx aluminum alloy developed on the basis of 2024 aluminum alloy by reducing the composition of impurity elements and optimizing the composition of main alloy elements; it has high specific strength and high damage tolerance. It is an important structural material in the aviation field and is widely used in high damage tolerance design parts such as the lower wing of the aircraft. [0003] During the solidification process of 2324 alloy, various precipitation phases will be formed, such as low melting point ternary eutectic phase α(Al)+θ(Al2Cu)+S(Al2CuMg), primary phases such as Fe and Si rich in impurity elements Fe and Si, As well as θ (Al2Cu), S (Al2CuMg), etc. formed by non-equilibrium solidification...

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Problems solved by technology

[0003] During the solidification process of 2324 alloy, various precipitated phases will be formed, such as the low melting point ternary eutectic phase α(Al)+θ(Al2Cu)+S(Al2CuMg), primary phases such as rich Fe and Si containing impurity elements Fe and Si, And θ(Al2Cu), S(Al2CuMg) formed by non-equilibrium solidification, etc., the primary phase is large and hard and brittle, and stress concentration is easy to occur around the phase, and cracking will occur under lower stress, which becomes the source of cracks and reduces the mechanical properties of the alloy. At the same time, the non-equilibrium phase gathers a large amount of alloying elements Mg and Cu to reduce the solid solubility of the aluminum alloy matrix, which reduces the aging precipitation kinetics, reduces the density and volume fraction of the precipitated phase, and reduces the aging strengthening effect.

Single-stage homogenization mainly refers to raising the ingot to a fixed temperature and holding it for a period of time, but it can only be held at a lower temperature, because the melting point of the eutectic phase with a low melting point is low, and continuing to increase the temperature will cause The eutectic phase with low melting point melts, resulting in overburning, and the melting back effect of the primary phase is not ideal due to the low temperature

Two-stage homogenization is to first keep warm at a lower temperature for a period of time, the purpose of which is to dissolve the eutectic phase with a low melting point, thereby increasing the temperature of the second-stage homogenization, and continue to heat to a higher temperature to continue the heat preservation, and the two-stage homogenization Although it can achieve the purpose of eliminating the eutectic structure formed by non-equilibrium solidification and the coarse θ and S phases, the holding time is longer, especially at a lower temperature for a longer time to make the eutectic phase with low melting point Fully dissolve

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