Abstract
In this paper, the mechanical properties and microstructures of an Al-Zn-Mg-Cu alloy subject to two-step aging treatment were systematically investigated. The results indicate that the mechanical strength and tensile ductility of the alloy can be significantly improved by pre-aging treatment at 120 °C for 6 h and then by second-step aging treatment at 165 °C for 12 h. After second-step aging treatment at 165 °C for 12 h, the tensile strength and yield strength of the alloy reach 718 and 654 MPa, increased by ~ 23 and ~ 35%, respectively, compared to the alloy without aging treatment. The increment in the strength is mainly attributed to the formation of ultrafine metastable η′ phase dispersed in the matrix. The fracture mode of the aging treated alloy includes both intergranular fracture and dimpled transgranular fracture. The coarse grain boundary precipitates (MgZn2 phase) and the wide precipitation free zones are beneficial to the tensile ductility of the alloy.
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The work is supported by National Natural Science Foundation of China (51531009 and 51820105001). We would like to thank the Advanced Research Center of Central South University for TEM technical support.
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Wang, F., Gong, Y., Du, Y. et al. Microstructures and Mechanical Properties of an Al-Zn-Mg-Cu Alloy Processed by Two-Step Aging Treatment. J. of Materi Eng and Perform 29, 4404–4411 (2020). https://doi.org/10.1007/s11665-020-04980-x
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DOI: https://doi.org/10.1007/s11665-020-04980-x