Microstructure evolution and mechanical properties of a large-sized ingot of Mg-9Gd-3Y-1.5Zn-0.5Zr (wt%) alloy after a lower-temperature homogenization treatment

Zhi-yong Xue; Yue-juan Ren; Wen-bo Luo; Yu Ren; Ping Xu; Chao Xu

doi:10.1007/s12613-017-1405-6

Volume 24 Issue 3

Mar. 2017

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Article Navigation > International Journal of Minerals, Metallurgy and Materials > 2017 > 24(3): 271-279

Zhi-yong Xue, Yue-juan Ren, Wen-bo Luo, Yu Ren, Ping Xu, and Chao Xu, Microstructure evolution and mechanical properties of a large-sized ingot of Mg-9Gd-3Y-1.5Zn-0.5Zr (wt%) alloy after a lower-temperature homogenization treatment, Int. J. Miner. Metall. Mater., 24(2017), No. 3, pp. 271-279. https://doi.org/10.1007/s12613-017-1405-6

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Zhi-yong Xue, Yue-juan Ren, Wen-bo Luo, Yu Ren, Ping Xu, and Chao Xu, Microstructure evolution and mechanical properties of a large-sized ingot of Mg-9Gd-3Y-1.5Zn-0.5Zr (wt%) alloy after a lower-temperature homogenization treatment, Int. J. Miner. Metall. Mater., 24(2017), No. 3, pp. 271-279. https://doi.org/10.1007/s12613-017-1405-6

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Research Article

Microstructure evolution and mechanical properties of a large-sized ingot of Mg-9Gd-3Y-1.5Zn-0.5Zr (wt%) alloy after a lower-temperature homogenization treatment

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Corresponding author:
Zhi-yong Xue E-mail: xuezy@ncepu.edu.cn
Received: 12 July 2016; Revised: 8 November 2016; Accepted: 9 November 2016

Abstract

Abstract

In this paper, a large-sized ingot of Mg-9Gd-3Y-1.5Zn-0.5Zr (wt%) alloy with a diameter of 600 mm was successfully prepared by the semi-continuous casting method. The alloy was subsequently annealed at a relatively low temperature of 430℃ for 12 h as a homogenization treatment. The microstructure and room-temperature mechanical properties of the alloy were investigated systematically. The results show that the as-cast alloy contained a mass of discontinuous lamellar-shaped 18R long-period stacking ordered (LPSO) phases with a composition of Mg₁₀ZnY and an α-Mg matrix, along with net-shaped Mg₅(Y,Gd) eutectic compounds at the grain boundaries. Most of the eutectic compounds dissolved after the homogenization treatment. Moreover, the amount and dimensions of the lamellar-shaped LPSO phase obviously increased after the homogenization treatment. The structure of the phase transformed into 14H-type LPSO with composition Mg₁₂Zn(Y,Gd). The mechanical properties of the heat-treated large-sized alloy ingot are uniform. The ultimate tensile strength (UTS) and tensile yield strength (TYS) of the alloy reached 207.2 MPa and 134.8 MPa, respectively, and the elongation was 3.4%. The high performances of the large-sized alloy ingot after the homogenization treatment is attributed to the strengthening of the α-Mg solid solution and to the plentiful LPSO phase distributed over the α-Mg matrix.
- magnesium alloys;
- ingots;
- homogenization;
- microstructural evolution;
- mechanical properties

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