Effect of secondary aging temperature on microstructure and properties of 7B04-T74 aluminum alloy sheet

doi:10.13251/j.issn.0254-6051.2021.10.014

Abstract

Abstract: Effect of secondary aging temperature on microstructure and properties of the 2 mm thickness 7B04-T74 alloy sheet was studied by means of optical microscope, transmission electron microscope, tensile test, conductivity test, exfoliation corrosion test and fatigue limit test. The results show that when the secondary aging temperature gradually increases from 165 ℃ to 175 ℃, the grain structure characteristics of the 7B04-T74 alloy have no obvious change, the number of precipitates within the grain decreases but their size increases, and the precipitates at grain boundary are coarse and intermittent distribution. Tensile strength and yield strength of the 7B04-T74 aluminum alloy sheet at room temperature are significantly reduced, the elongation has no obvious change, the conductivity is significantly increased, and the exfoliation corrosion grade has no obvious change trend. By comparing the structure and properties of the 7B04 aluminum alloy at different secondary aging temperatures, it comes to the conclusion that the optimal secondary aging temperature for 2 mm thickness 7B04 alloy sheet from annealing state to T74 state is 173 ℃.

Key words: 7B04 aluminum alloy, aging, microstructure, properties

CLC Number:

TG146.2

Yao Ze, Zhong Liwei, Lu Yingfeng, Feng Zhaohui, Chen Junzhou. Effect of secondary aging temperature on microstructure and properties of 7B04-T74 aluminum alloy sheet[J]. Heat Treatment of Metals, 2021, 46(10): 86-91.

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