Effect of aging on microstructure and bending properties of 7022 aluminum alloy

doi:10.13251/j.issn.0254-6051.2022.07.026

Abstract

Abstract: Effect of aging treatment on microstructure and mechanical properties of 7022 aluminum alloy was studied by means of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) analysis, X-ray diffraction (XRD), electron backscatter diffraction (EBSD), tensile and bending test. The results show that the 7022 aluminum alloy matrix after solution treatment still contains a large amount of black insoluble second phases and these phases are mainly composed of α-Al, MgZn₂, Al₂CuMg and Al₇Cu₂Fe phases. As the aging progresses, the Al₂CuMg and Al₇Cu₂Fe phases gradually dissolve, and the Mg(Zn, Cu, Al)₂ phase, which is similar in properties to the MgZn₂ phase, precipitates, and the grains grow gradually, resulting in an obvious precipitation strengthening effect. The bending strength of the specimen is mainly affected by the number and size of the second phase particles and grain size. Under the aging condition at 110 ℃ for 10 h, the alloy with dispersed fine second phase particles and suitable grain size has better bending strength and tensile strength, and the values are 21.7 MPa and 608 MPa, respectively.

Key words: 7022 aluminum alloy, bending properties, aging treatment, microstructure, mechanical properties

CLC Number:

TG146.2

Yin Jian, Jin Kang, Li Cheng, Dong Qi, Shen Zhi, Zhang Bo. Effect of aging on microstructure and bending properties of 7022 aluminum alloy[J]. Heat Treatment of Metals, 2022, 47(7): 144-150.

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