Method for improving plasticity of cast Al-Li alloy

Abstract

The invention relates to a method for improving the plasticity of cast Al-Li alloy. The method includes the steps that alloying elements capable of forming Al3M particles of the L12-type structure with Al are added in the casting process of the cast Al-Li alloy; and the alloying elements include at least two of Zr, Sc, Er and Yb. Through combined addition of the alloying elements capable of forming the Al3M particles of the L12-type structure with the Al in the cast Al-Li alloy, the alloy as-cast structure can be refined obviously, the alloy can be promoted to separate out coherency Al3M particles in the solid solution process, the precipitation density of composite particles Al3(M and Li) in the cast Al-Li alloy is increased ultimately, and thus alloy plasticity is improved. By adoption of the method, the cast Al-Li alloy can be further subjected to short-time 'preageing' treatment at a low temperature before solid solution, the number of the Al3M particles in an alloy matrix can be further increased, and the alloy plasticity is improved.

Description

technical field [0001] The invention discloses a method for improving the plasticity of cast aluminum-lithium alloys, in particular to a method for combining energy addition and aluminum to form a structure of L1 2 Type Al 3 The invention discloses an alloying method of alloying elements of M particles and a heat treatment process, belonging to the technical field of non-ferrous metals. Background technique [0002] Adding 1wt% Li to aluminum can reduce the density of the alloy by 3% and increase the stiffness by 6%. Therefore, aluminum-lithium alloys have the characteristics of low density, high specific stiffness and high specific strength, and show broad application prospects in the aerospace field. Studies have shown that in addition to the above characteristics, aluminum-lithium alloys also have good fluidity and can be used to prepare components with complex shapes. The advantage of stiffness is more obvious, and it is very suitable for the requirements of low densit...

AI Technical Summary

Problems solved by technology

However, in the actual smelting process of traditional aluminum alloys, intermediate alloys such as Al-Zr and Al-Sc are generally added to the melt last, and the diffusion rate of alloying elements such as Zr and Sc in the aluminum melt is much lower than that of Cu , Mg and other elements, which not only weakens its effect of refining aluminum alloy grains, but also tends to retain primary Al 3 Zr and Al 3 The characteristics of Sc particles are hard and brittle, which damages the plasticity of the alloy

At the same time, the study also found that the addition of Zr, Sc and other alloying elements alone does not significantly improve the plasticity of cast aluminum-lithium alloys.

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