Abstract
The hot-tearing susceptibility (HTS) of Mg-6Zn-xGd (x=0.5, 1, 2, 3, 4, 6) alloys was evaluated using a constrained rod casting (CRC) method. The results show that the HTS curve follows a typical “Λ” shape with the increase of Gd content. The Mg-6Zn-2Gd alloy has the highest while Mg-6Zn-6Gd alloy has the lowest HTS value. The hot-tearing behavior characteristics of Mg-6Zn-xGd alloys were further studied through a multifunctional hot-tearing test device. According to the dendrite contact point inferred from the stress curve, the Clyne-Davies criterion was modified and found to be accurate in predicting the HTS of Mg-6Zn-xGd alloys. Microstructure observation reveals that the grain size and the volume of eutectic liquid are the two key factors affecting HTS of Mg-6Zn-xGd alloys. The large grain with columnar structure can easily promote initiation and propagation of hot-tearing due to the poor feeding and coordinating deformation capability, which have a harmful effect on HTS. A higher volume fraction of eutectic phase can refill the cracking and provide continuous feeding channels by dendrite bridge and thicker liquid film, thus increase the hot-tearing resistance.
Article PDF
Similar content being viewed by others
References
Pan F S, Yang M B, Chen X H. A review on casting magnesium alloys: Modification of commercial alloys and development of new alloys. J. Mater. Sci. Technol., 2016, 32(12): 1211–1221.
Song J F, She J, Chen D L, et al. Latest research advances on magnesium and magnesium alloys worldwide. J. Magnes. Alloy., 2020, 8(1): 1–41.
Fu P H, Peng L M, Jiang H Y. Tensile properties of high strength cast Mg alloys at room temperature: A review. China Foundry, 2014, 11(4): 277–286.
Xiao L, Yang G Y, Chen J M, et al. Microstructure, texture evolution and tensile properties of extruded Mg-4.58Zn-2.6Gd-0.16Zr alloy. Mater. Sci. Eng. A, 2019, 744: 277–289.
Gao X, Nie J F. Characterization of strengthening precipitate phases in a Mg-Zn alloy. Scr. Mater., 2007, 56(8): 645–648.
Zhang G J, Wang Y, Liu Z, et al. Influence of Al addition on solidification path and hot tearing susceptibility of Mg-2Zn-(3+0.5x)Y-xAl alloys. J. Magnes. Alloy., 2019, 7(2): 272–282.
Zhou L, Huang Y D, Mao P L, et al. Influence of composition on hot tearing in binary Mg-Zn alloys. Int. J. Cast. Metal. Res., 2011, 24(3–4): 170–176.
Clyne T W, Davies G J. The influence of composition on solidification cracking susceptibility in binary alloys. Br. Foundaryman, 1981, 74: 65–73.
Zhou L, Huang Y D, Mao P L, et al. Investigation on hot tearing of Mg-Zn-(Al) alloys. Magnesium Technology, 2011: 125–130.
Wang Z, Song J F D, Huang Y, et al. An investigation on hot tearing of Mg-4.5Zn-(0.5Zr) alloys with Y additions. Metall. Mater. Trans. A, 2015, 46(5): 2108–2118.
Gunde P, Schiffl A, Uggowitzer P J. Influence of yttrium additions on the hot tearing susceptibility of magnesium-zinc alloys. Mater. Sci. Eng. A, 2010, 527(26): 7074–7079.
Gao L, Chen R S, Han E H. Effects of rare-earth elements Gd and Y on the solid solution strengthening of Mg alloys. J. Alloys Compd., 2009, 481(1–2): 379–384.
Zhan L, Le Y Z, Feng Z J, et al. Effect of Gd addition on mechanical and microstructural properties of Mg-xGd-2.6Nd-0.5Zn-0.5Zr cast alloys. China Foundry, 2020, 17(3): 212–218.
Yin S Q, Zhang Z Q, Liu X, et al. Effects of Zn/Gd ratio on the microstructures and mechanical properties of Mg-Zn-Gd-Zr alloys. Mater. Sci. Eng. A, 2017, 695: 135–143.
Liu S J, Yang G Y, Luo S F, et al. Microstructure and mechanical properties of sand mold cast Mg-4.58Zn-2.6Gd- 0.18Zr magnesium alloy after different heat treatments. J. Alloys Compd., 2015, 644: 846–853.
Srinivasan A, Wang Z, Huang Y D, et al. Hot tearing characteristics of binary Mg-Gd alloy castings. Metall. Mater. Trans. A, 2013, 44A(5): 2285–2298.
Luo S F, Yang G Y, Zou Z, et al. Hot tearing susceptibility of binary Mg-Gd alloy castings and influence of grain refinement. Adv. Eng. Mater., 2018, 20(8): 1800139.
Cao G, Kou S. Hot cracking of binary Mg-Al alloy castings. Mater. Sci. Eng. A, 2006, 417(1–2): 230–238.
Li J L, Chen R S, Ma Y Q, et al. Hot tearing of sand cast Mg-5wt.% Y-4wt.% RE (WE54) alloy. Acta Metall. Sin-Engl., 2013, 26(6): 728–734.
Emadi D, Whiting L V, Nafisi S, et al. Applications of thermal analysis in quality control of solidification processes. J. Therm. Anal. Calorim., 2005, 81(1): 235–241.
Huang Z H, Liang S M, Chen R S, et al. Solidification pathways and constituent phases of Mg-Zn-Y-Zr alloys. J. Alloys Compd., 2009, 468(1–2): 170–178.
Suyitno, Kool W H, Katgerman L. Integrated approach for prediction of hot tearing. Metall. Mater. Trans. A, 2009, 40(10): 2388–2400.
Shankar S, Riddle Y W, Makhlouf M M. Nucleation mechanism of the eutectic phases in aluminum-silicon hypoeutectic alloys. Acta Mater., 2004, 52(15): 4447–4460.
Huang H, Fu P H, Wang Y X, et al. Effect of pouring and mold temperatures on hot tearing susceptibility of AZ91D and Mg-3Nd-0.2Zn-Zr Mg alloys. Trans. Nonferrous Met. Soc. China, 2014, 24(4): 922–929.
Caceres C H, Blake A. The strength of concentrated Mg-Zn solid solutions. Phys. Stat. Sol. A, 2002, 194(1): 147–158.
Easton M A, Wang H, Grandfield J, et al. Observation and prediction of the hot tear susceptibility of ternary Al-Si-Mg alloys. Metall. Mater. Trans. A, 2012, 43(9): 3227–3238.
Acknowledgements
This work was supported by the National Key R&D Program of China (Grant No. 2018YFB1106800), and the National Natural Science Foundation of China (Grant No. 51771152).
Author information
Authors and Affiliations
Corresponding author
Additional information
Guang-yu Yang Male, born in 1967, Ph.D., Professor. His research interests mainly focus on the development of high strength Mg and Al cast alloys, and liquid metal forming technology. To date, he has published more than 40 technical papers.
Rights and permissions
About this article
Cite this article
Qin, H., Yang, Gy., Zheng, Xw. et al. Effect of Gd content on hot-tearing susceptibility of Mg-6Zn-xGd casting alloys. China Foundry 19, 131–139 (2022). https://doi.org/10.1007/s41230-022-1117-z
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s41230-022-1117-z