A high-strength toughness deformed aluminum-lithium alloy compounded with multiple rare earth elements and its preparation method

Abstract

The invention discloses a high strength and toughness deformed aluminum-lithium alloy in compound adding of various rare earth elements and a preparation method of the alloy. The alloy comprises, by weight percentage, 0.8-3.0% of Li, 3.0-6.0% of Cu, 0.2-3.0% of Mg, 0.2-1.5% of Zn, 0.1-0.15% of Zr, 0.1-1.0% of Gd, 0.1-1.0% of Nd, 0.1-1.0% of Yb and the balance Al and inevitable impurity elements. According to the high strength and toughness deformed aluminum-lithium alloy in compound adding of the various rare earth elements and the preparation method of the alloy, compound adding of the rare earth elements of Gd, Nd and Yb is performed in the alloy, the three rare earth cooperate with one another to achieve various effects of fine grain strengthening, precipitation strengthening, substructure strengthening, solid solution strengthening and the like, so that the strength and the toughness of the alloy are both improved, the made aluminum-lithium alloy is uniform in microstructure and stable in various performances, and better strength and toughness are achieved. The alloy has broad application prospects in the fields of aerospace, high-speed rails, robots, household appliances and the like.

Description

technical field [0001] The invention belongs to the technical field of metal materials, and relates to a high-strength toughness deformed aluminum-lithium alloy compounded with various rare earth elements and a preparation method thereof, in particular to an Al-Cu-Li-X alloy compounded with various rare earth elements, A deformed aluminum-lithium alloy with low density, high elastic modulus, high strength and good toughness is obtained through certain extrusion process and heat treatment means. Background technique [0002] Aluminum-lithium alloy is a kind of aluminum-lithium alloy with low density, high elastic modulus, high specific strength and high specific stiffness. It is listed as the main material in the aerospace field along with fiber composite materials, and is gradually replacing traditional aluminum alloys. Studies have reported that every addition of 1wt.% Li element in Al alloys will reduce the alloy density by 3%, and increase the elastic modulus by 6%, which...

AI Technical Summary

Problems solved by technology

Although the transverse performance elongation of the T6 state plate of 2195 aluminum-lithium alloy reaches 12.1%, its yield strength is 551MPA and tensile strength is 592MPA, which does not reflect the ideal strength of Al-Cu-Li-X alloy

At present, there have been some research reports on adding trace rare earth elements to aluminum-lithium alloys. Li Haoran and others from Central South University studied the influence of different Ce contents on the microstructure and properties of Al-Cu-Li-X alloys during deformation heat treatment. After adding Ce The Al-4.15Cu-1.25Li-0.40Mg-0.40Ag-0.5Zn-0.12Zr-xCe alloy in the T8 peak aging state has a yield strength of 560MPA, a tensile strength of 597MPA, and an elongation of 8%; Chinese Academy of Sciences Gui Quanhong et al. from the Institute of Metal Research studied the effect of Y on the tensile properties and fracture behavior of 8090Al-Li alloy. The yield strength of the 8090 alloy after Y was extruded and rolled in the peak aging state was the highest 340MPA, and the tensile strength was 340MPA. The highest mildness is 434MPA, and the elongation is as high as 10.6%. Yin Dengfeng of Central South University and others studied the effect of Sc on the microstructure and mechanical properties of 2195 Al-Li alloy strain aging, and the elongation of 2195 with 0.15% Sc added under peak aging conditions There is 11.2%, but yield strength and tensile strength are respectively 534MPA and 565MPA, have improved elongation, but alloy strength has not significantly improved; A kind of rolling deformation high strength high toughness aluminum disclosed in Chinese patent document CN108425050A (publication number) The lithium alloy contains rare earth elements Y0.06-0.12%, the elongation of the alloy is up to 11.5%, and the highest tensile strength and yield strength are respectively 562MPA and 525MPA; The rolling deformation aluminum-lithium alloy of element, containing rare earth element La 0.4-0.6% and Sc 0.1-0.5%, its tensile strength can reach 750MPA after aging, although toughness has improved but effect is still not obvious; Chinese patent document CN103993204A ( Publication No.) discloses a low-anisotropy aluminum-lithium alloy rod containing rare earth elements La and Ce: 0.2-0.4%. Its tensile strength and yield strength are extremely high in the T6 state, but the elongation is up to 2.5%.

Judging from the existing research results, the effect of adding rare earth elements such as Ce, La, Y, and Sc to improve the strength and toughness of the alloy is still limited, and most alloys still retain or have high strength and low elongation, or high elongation. The defect of low strength has not yet achieved high strength and good toughness at the same time, and it is still not enough to make the strength and toughness of aluminum-lithium alloys reach or exceed the level of ordinary aviation aluminum alloys.

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