Effect of aging time on microstructure and properties of 7075-T6 aluminum alloy

doi:10.13251/j.issn.0254-6051.2023.07.022

Abstract

Abstract: Effect of aging time on microstructure and properties of 7075-T6 aluminum alloy were systematically studied by means of hardness test, tensile test, conductivity test, metallography microscope, X-ray diffractometer and scanning electron microscope. The results show that the microstructure of the 7075-T6 aluminum alloy changes significantly with the extension of aging time. The grain size is refined from 88.76 μm of the original state(0 h) to 35.78 μm after aging for 18 h, and then coarsened to 67.88 μm after aging for 24 h. The hardness and conductivity of the 7075-T6 aluminum alloy increase with the extension of aging time, and the maximum values appear when aging for 4 h and 24 h, respectively. It can be seen from the microstructure evolution that the increase of aging time will reduce the G.P. zone and increase the η′(MgZn₂) phase, while both the η′phase and the G.P. zone can inhibit the dislocation movement, and improve the strength and conductivity of the alloy. When the aging time is too long, the overaging occurs, the grains coarsen again, and the mechanical properties of the alloy are reduced.

Key words: 7075-T6 aluminum alloy, aging time, microstructure, mechanical properties, over aging

CLC Number:

TG161

Tang Peng, Huang Jialiang, Liu Qiannan, Deng Songyun. Effect of aging time on microstructure and properties of 7075-T6 aluminum alloy[J]. Heat Treatment of Metals, 2023, 48(7): 131-137.

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