China Foundry
Title: Effect of secondary aging on microstructure and properties of cast Al-Cu-Mg alloy
Author: *Rui-ming Su1, Yong-xin Jia1, Jian Xiao2, Guang-long Li1, Ying-dong Qu1, and Rong-de Li1
Address: 1. School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870, China; 2. Guizhou Yonghong Aviation Machinery Limited Liability Company, Guiyang 550009, China
Key words: cast Al-Cu-Mg alloy; secondary aging; mechanical properties; corrosion resistance; strengthening phase
CLC Nmuber: TG146.21
Document Code: A
Article ID: 1672-6421(2023)01-071-07
Abstract:
To obtain better comprehensive properties of cast Al-Cu-Mg alloys, the secondary aging (T6I6) process (including initial aging, interrupted aging and re-aging stages) was optimized by an orthogonal method. The microstructures of the optimized Al-Cu-Mg alloy were observed by means of scanning electron microscopy and transmission electron microscopy, and the properties were investigated by hardness measurements, tensile tests, exfoliation corrosion tests, and intergranular corrosion tests. Results show that the S phase and θ' phase simultaneously exist in the T6I6 treated alloy. Appropriately increasing the temperature of the interrupted aging in the T6I6 process can improve the mechanical properties and corrosion resistance of Al-Cu-Mg alloy. The optimal comprehensive properties (tensile strength of 443.6 MPa, hardness of 161.6 HV) of the alloy are obtained by initial aging at 180 °C for 2 h, interrupted aging at 90 °C for 30 min, and re-aging at 170 °C for 4 h.