Abstract
The microstructure evolution and mechanical properties of Mg–10Gd–3Y–x Zn–0.6Zr ( x = 0.5, 1, and 1.5 wt%) alloys in the as-cast, solution-treated, and peak-aged conditions have been investigated systematically. The results indicate that the microstructure of the as-cast alloy with 0.5% Zn consists of α-Mg, (Mg,Zn)3RE and Mg24(RE,Zn)5 phases, while the alloy with 1.0 and 1.5% Zn consists of α-Mg, (Mg,Zn)3RE and some stacking faults. Moreover, 18R-LPSO phases are observed in the as-cast alloy with 1.5% Zn. The formation of LPSO phases involves not only stacking sequence ordered but also chemical composition ordered. After solution treatment, the Mg24(RE,Zn)5, (Mg,Zn)3RE, stacking faults, and 18R-LPSO phases transform into 14H-LPSO phases. The 14H-LPSO phase plays an important role in the improvement of mechanical properties, especially for the ductility. The β′ phase with a bco structure precipitates in the peak-aged alloys results in precipitation hardening, significantly improving the tensile strength, but it leads to poor ductility.
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ACKNOWLEDGMENTS
This work is supported by the National Natural Science Foundation of China (Nos. 51774254, 51774253, 51701187, U1610123, 51674226, 51574207, and 51574206), The Science and Technology Major Project of Shanxi Province (No. MC2016-06), and Shanxi Province Science Foundation for Youths (No. 201601D021062).
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Ding, Z., Zhao, Y., Lu, R. et al. Microstructure evolution and mechanical properties of Mg–10Gd–3Y–x Zn–0.6Zr alloys. Journal of Materials Research 33, 1797–1805 (2018). https://doi.org/10.1557/jmr.2018.100
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DOI: https://doi.org/10.1557/jmr.2018.100