Effect of Two-Stage Aging on Microstructure and Properties of Al-Mg-Si Alloys

Abstract:

The effects of two-stage aging on the microstructures, tensile properties and intergranular corrosion (IGC) sensitivity of Al-Mg-Si alloys were studied by tensile testing and IGC experiments and transmission electron microscope (TEM). The results show that the two-stage aging (180°C, 2h+160°C, 120h) can reduce the IGC sensitivity without decrease the tensile properties. The grain is distributed with high-density β′′ phases, and the grain boundary phases are spherical and intermittently distributed. The formation of the microstructure characteristic is due to the lower re-aging temperature, which results in a decline differences in the diffusion rate between the matrix and grain boundaries. As a result, the pre-precipitated phase can maintain a better strengthening effects due to the slower growth rate. The pre-precipitated phase of the grain boundary presents a spherical and intermittent distribution due to the fast coarsening speed.

• Periodical: Key Engineering Materials (Volume 905)
• Pages: 51-55
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.905.51
• Online since: January 2022
• Authors: Li Wang*, Ya Ya Zheng, Shi Hu Hu
• Keywords: Al-Mg-Si, Intergranular Corrosion, Microstructure, Two-Stage Aging

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