Abstract
The microstructure evolution and age-hardening response for different Sm/Sn ratios (0–2.55, in wt.%) of Mg-Sn-Sm alloys were investigated. The second phase formation in as-cast alloys and the Mg3Sm precipitates formed in aged alloys were characterized using XRD, FESEM and HAADF-STEM with EDS techniques. Results indicate that the Sm/Sn ratio has a great influence on the phase constitution, α-Mg grain size and age-hardening response. With the increment of Sm/Sn ratio, Mg41Sm5 and thermally stable MgSnSm phases precipitate. When the Sm/Sn ratio is about 1.19, the secondary dendrite arm spacing of α-Mg grains significantly decreases. Furthermore, the alloy with Sm/Sn ratio up to 2.55 exhibits the highest age-hardening response, the hardness value increases from 52 HB at solution-treated condition to 74 HB at peak-aged condition (ageing at 220 °C for a short time of 4 h). This is attributed to the large volume fraction of needle-like Mg3Sm precipitates formed in the α-Mg matrix during ageing treatment, which results in a significant precipitation strengthening effect.
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Song J F, She J, Chen D L, et al. Latest research advances on magnesium and magnesium alloys worldwide. Journal of Magnesium and Alloys, 2020, 8: 1–41.
Gavras S, Zhu S M, Nie J F, et al. On the microstructural factors affecting creep resistance of die-cast Mg-La-rare earth (Nd, Y or Gd) alloys. Materials Science and Engineering A, 2016, 675: 65–75.
Liu C Q, Chen H W, Nie J F. Interphase boundary segregation of Zn in Mg-Sn-Zn alloys. Scripta Materialia, 2016, 123: 5–8.
Pan F S, Yang M B, Chen X H. A review on casting magnesium alloys: Modification of commercial alloys and development of new alloys. Journal of Materials Science and Technology, 2016, 32: 1211–1221.
Liu C Q, Chen H W, Liu H, et al. Metastable precipitate phases in Mg-9.8 wt%Sn alloy. Acta Materialia, 2018, 144: 590–600.
Narreri G, Mahmudi R. Effects of Ca additions on the microstructural stability and mechanical properties of Mg-5%Sn alloy. Materials and Design, 2011, 32: 1571–1576.
Li W D, Huang X F, Huang W G. Effects of Ca, Ag addition on the microstructure and age-hardening behavior of a Mg-7Sn (wt.%) alloy. Materials Science and Engineering A, 2017, 692: 75–80.
Muthuraja C, Akalya A, Ahmed R R, et al. Experimental investigation and thermodynamic calculation of the phase equilibria in the Mg-rich region of Mg-Sn-Y alloys. Journal of Alloys and Compounds, 2017, 695: 3559–3572.
Yang M B, Pan F S, Cheng L, et al. Effects of cerium on as-cast microstructure and mechanical properties of Mg-3Sn-2Ca magnesium alloy. Materials Science and Engineering A, 2009, 512: 132–138.
Yang M B, Pan F S. Effects of Y addition on as-cast microstructure and mechanical properties of Mg-3Sn-2Ca (wt.%) magnesium alloy. Materials Science and Engineering A, 2009, 525: 112–120.
Yang M B, Zhu Y, Liang X F, et al. Effects of Gd addition on as-cast microstructure and mechanical properties of Mg-3Sn-2Ca magnesium alloy. Materials Science and Engineering A, 2011, 528: 1721–1726.
Chen Y A, Wang Y, Gao J J. Microstructure and mechanical properties of as-cast Mg-Sn- Zn-Y alloys. Journal of Alloys and Compounds, 2018, 740: 727–734.
Wang P Q, Guo E Y, Wang X J, et al. The influence of Sc addition on microstructure and tensile mechanical properties of Mg-4.5Sn-5Zn alloys. Journal of Magnesium and Alloys, 2019, 7: 456–465.
Xia X Y, Sun W H, Luo A A, et al. Precipitation evolution and hardening in Mg-Sm-Zn-Zr alloys. Acta Materialia, 2016, 111: 335–347.
Zhang Y, Huang X F, Li Y, et al. Effects of samarium addition on as-cast microstructure, grain refinement and mechanical properties of Mg-6Zn-0.4Zr magnesium alloy. Journal of Rare Earths, 2017, 35: 494–502.
Yu H S, Guo X F, Cui H B. Microstructures and tensile properties of as-cast Mg-5Sn-1Si magnesium alloy modified with trace elements of Y, Bi, Sb and Sr. China Foundry, 2021, 18(1): 9–17.
Ali Y, Qiu D, Jiang B, et al. Current research progress in grain refinement of cast magnesium alloys: A review article. Journal of Alloys and Compounds, 2015, 619: 639–651.
Kozlov O A, Grobner J, Schmid F R. Phase formation in Mg-Sn alloys modified by Ca and Ce. Journal of Phase Equilibria and Diffusion, 2014, 35: 502–517.
Wang Q, Chen Y G, Xiao S F, et al. Study on microstructure and mechanical properties of as-cast Mg-Sn-Nd alloys. Journal of Rare Earths, 2010, 28: 790–793.
Yang M B, Hou M D, Zhang J, et al. Effects of Ce, Y and Gd additions on as-cast microstructure and mechanical properties of Mg-3Sn-2Sr magnesium alloy. Transactions of Nonferrous Metals Society of China, 2014, 24: 2497–2506.
Sasaki T T, Ohishi K, Ohkubo T, et al. Enhanced age hardening response by the addition of Zn in Mg-Sn alloys. Scripta Materialia, 2006, 55(2): 251–254.
Mendis C L, Bettle C J, Gibson M A, et al. An enhanced age hardening response in Mg-Sn based alloys containing Zn. Materials Science and Engineering A, 2006, 435: 163–171.
Zheng J X, Zhou W M, Chen B. Precipitation in Mg-Sm binary alloy during isothermal ageing: Atomic-scale insights from scanning transmission electron microscopy. Materials Science and Engineering A, 2016, 669: 304–311.
Xie H B, Liu B S, Bai J Y, et al. Re-recognition of the aging precipitation behavior in the Mg-Sm binary alloy. Journal of Alloys and Compounds, 2020, 814: 1–6.
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This work was financially supported by the Natural Science Foundation of Inner Mongolia under Grant No. 2020MS05014, and the Science and Technology Planning of Inner Mongolia under Grant No. 2020GG0318.
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Feng Liu Male, born in 1990, Master. His research interests mainly focus on the microstructures and mechanical properties of magnesium alloys.
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Liu, F., Hu, Wx., Yang, Zh. et al. Microstructure evolution and age-hardening response in Mg-Sn-Sm alloys under a wide range of Sm/Sn ratio. China Foundry 19, 211–217 (2022). https://doi.org/10.1007/s41230-022-1120-4
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DOI: https://doi.org/10.1007/s41230-022-1120-4